Evaluation of nucleotide MALDI-TOF MS on bronchoalveolar lavage fluid for pulmonary Tuberculosis: experience from a tertiary hospital in southwestern China

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A retrospective study was conducted on suspected PTB patients admitted to Chongqing Public Health Medical Center between May 2021 and January 2022. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC) values of nucleotide MALDI-TOF MS as well as smear microscopy, Mycobacterium Growth Indicator Tube 960 culture (MGIT 960 culture), and Xpert MTB/RIF were calculated and compared. Total of 343 presumed PTB cases were enrolled. Overall, using the clinical diagnosis as reference, the sensitivity and NPV of nucleotide MALDI-TOF MSwas 71.5% and 43.1%, respectively, significantly higher than smear microscopy (22.6%, 23.2%), MGIT 960 culture (40.6%, 18.9%), Xpert MTB/RIF (40.8%, 27.9%). Furthermore, nucleotide MALDI-TOF MS also outperformed over Xpert MTB/RIF and MGIT 960 culture on smear-negative BALFs. Approximately 50% and 30% of patients benefited from nucleotide MALDI-TOF MS compared with smear and MGIT 960 culture or Xpert MTB/RIF, respectively. This study demonstrated that the analysis of BALF with nucleotide MALDI-TOF MS provided an accurate and promising tool for the early diagnosis of PTB. Biological sciences/Microbiology Biological sciences/Microbiology/Clinical microbiology bronchoalveolar lavage fluid nucleotide MALDI-TOF MS Xpert MTB/RIF pulmonary tuberculosis diagnosis Figures Figure 1 Figure 2 Figure 3 Introduction Tuberculosis (TB), a communicable disease mainly due to infection with Mycobacterium tuberculosis (MTB), remains a major public health problem that afflicts approximately 10 million people worldwide, of which, pulmonary tuberculosis (PTB) is the most common form 1 . Early PTB diagnosis and initial proper treatment are crucial for the prevention of disease progression 2 . Microbiological tests based on high-quality respiratory specimens are essential to enable accurate diagnosis of PTB. Sputum specimens are the most common type; however, the quality of them is difficult to ensure, especially in patients who unable to self-expectorate or have no sputum 3,4 . Alternatively, bronchoalveolar lavage fluid (BALF) is another sample type to be considered and favoured by physicians 5 . Currently, standard PTB microbiologically diagnostic methods in most hospitals usually include smear microscopy, culture, each with its own strengths and weaknesses 6 . Smear microscopy provides the advantage of speed, yet its sensitivity is insufficient nor can it differentiate MTB and nontuberculous mycobacteria (NTM). The culture method, including Mycobacterium Growth Indicator Tube 960 culture (MGIT 960 culture), remains the gold standard for the diagnosis of TB, but it demands high-level biosafety, high personnel expertise, poses risks of fragile contamination and most importantly has long turnaround time 7 , resulting the delayed diagnosis and potential drug resistance 8 . With the development of molecular technology, many methods for the rapid diagnosis of TB occur recent years, several of which have been recommended by the World Health Organization (WHO), like Xpert MTB/RIF assay, the first approved one 9 . Nucleotide MALDI-TOF MS assay, a relative novel technology, is matrix-assisted laser desorption ionization time-of-flight mass spectrometry based on nucleotide, possessing the advantages of rapidity, high throughput and high accuracy 10 . Several studies have demonstrated the promising application of this technique in TB diagnosis and its drug resistance 11,12 ; however, evaluation of this assay using BALF specimens in more real-world practices and different regions in China remains very limited. Here, we analysed the diagnostic performance of nucleotide MALDI-TOF MS assay on BALFs obtained from highly suspected PTB patients in southwestern region of China and compared the results to those of smear microscopy, MGIT 960 culture and Xpert MTB/RIF assay. Thus, we hope that the results of this study will contribute to the improvement of the clinic diagnosis of PTB. Materials and Methods Participants and Clinical Diagnosis We retrospectively reviewed the clinical and laboratory test results of patients with suspected PTB who underwent nucleotide MALDI-TOF MS assay on BALFs from May 2021 to January 2022 at Chongqing Public Health Medical Center (Chongqing, China), a tertiary TB designated hospital lacated at in Southwest China. Medical data were collected, including age, sex, previous TB treatment, clinical diagnosis, and comorbidities. We have no access to information that could identify individual participants during or after data collection. During this time, a total of 343 patients agreed to conduct nucleotide MALDI-TOF assay on BALFs. These samples were subjected to acid-fast bacilli smear microscopy, culture or the Xpert MTB/RIF assay. However, not all of these BALF samples were performed using culture or Xpert MTB/RIF assay; that is, 280 for MGIT 960 culture and 220 for Xpert MTB/RIF. Clinically diagnosed PTB cases were diagnosed based on the guidelines of ATS/CDC/IDSA and the Health Industry Standards of the People’s Republic of China Diagnosis of Tuberculosis (WS 288–2017). A patient diagnosed with confirmed PTB had one or more of the following criteria: ( 1 ) positive microbiological results based on culture or molecular tests of sputum, BALF, or puncture fluid; ( 2 ) positive results for MTB based on histopathological examination of puncture, biopsy, or surgical samples; and ( 3 ) improved symptoms after anti-TB treatment. Otherwise, cases were classified as non-PTB patients. A positive microbiological result was defined as any positive evidence of MTB detected in any sample provided by the patient admitted to our center, including BLAF, sputum, or puncture fluid samples, according to culture or Xpert MTB/RIF assay and regardless of the results of nucleotide MALDI-TOF MS assay. BALF collection Bronchoscopy was performed according to the Chinese Thoracic Society expert consensus. To collect BALF, 50 ~ 100 mL of isotonic saline was used for bronchial washing of the related sub-segment and 5–20 mL of the recovered BALFs were collected into the sterile containers and sealed. The containers were delivered immediately to the laboratory for smear microscopy, culture or Xpert MTB/RIF assay and nucleotide MALDI-TOF MS assay. Conventional test methods for BALF specimens The collected BALF samples were subjected for traditional test in our hospital as follows: ( 1 ) Acid-fast bacillus microscopy: The samples were liquefied and centrifuged to obtain a precipitate. The sediment was spread onto the front of a glass microscope slide, which was allowed to air dry and heat-fixed before staining with the Ziehl-Neelsen method. Smear results of 1 + or more acid-fast bacillus (AFB) were recorded as positive for statistical analysis. ( 2 ) MGIT 960 culture: The Mycobacteria Growth Indicator Tube (MGIT) 960 system (BD Diagnostics) was used for liquid culture. All samples were inoculated in the MGIT tubes were incubated in the corresponding instrument. ( 3 ) Xpert MTB/RIF assay: The testing was performed according to the manufacturer’s instructions (Cepheid, USA). Nucleotide MALDI-TOF MS assay The assay used Conlight TB&DR® assay, which was well-established and conducted by Shanghai Conlight Medical Co., Ltd. This assay integrates the sensitivity of PCR technology and the high throughput nature of mass spectrometry detection technology. One reaction can amplify up to 40 gene amplifications that can applied to single nucleotide polymorphism analysis, mutant detection, and other research areas. The specific procedures can be found in the literatures 11,13 . Briefly, the process includes the following six steps: extraction of nucleic acids from samples, PCR to obtain target fragments, shrimp alkaline phosphatase (SAP) reaction, extension reaction, detection on the MS instrument, and automatic analysis of results by MassARRAY analysis software. Statistical analysis All information of patients enrolled in the study were recorded in EXCEL. R 4.2.0 was used for statistical analysis. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with 95% confidence intervals (95% CI) were calculated. Chi-squared test was used for the comparison of indicators obtained from various methods. Receiver operating characteristic (ROC) curves and their areas under the curve (AUC) were used to evaluate the diagnostic accuracy. A two-tailed value of p < 0.05 was considered as statistical significance. Ethics statement The study protocol was approved by the Ethics Committee of Chongqing Public Health Medical Center of China (2023-013). This study was conducted in accordance with the principles of the Declaration of Helsinki of the World Medical Association and with Good Clinical Practice Guidelines. Results Basic information of the enrolled participants As shown in the flow chart (Fig. 1 ), we retrospectively screened suspected PTB cases who visited Chongqing Public Health Medical Center between May 2021 and January 2022 and found a total of 343 cases agreed to undergo nucleotide MALDI-TOF MS assay, which were enrolled in this study. BALF samples were obtained from all patients and subjected to nucleotide MALDI-TOF MS assay. At same time, routine laboratory tests were performed in our hospital as follows: all samples underwent smear microscopy, 280 of them were cultured on MGIT 960 system, and 220 were analyzed with Xpert MTB/RIF assay. Clinical diagnosis of PTB was finally made in 274 cases (79.9%) and the remaining (69, 20.1%) was classified as non-PTB patients. Demographic and clinical features of the study population were presented in Table 1 . Of the enrolled participants, 215 (62.7%) were males and 128 (37.3%) were females, with a median age of 46.0 years (interquartile range [IQR]: 31.0-58.5). Twenty-seven patients (7.9%) were diagnosed with diabetes mellitus (DM), 13 patients (3.8%) with hypertension, and 120 patients (35.0%) with a history of TB treatment. Table 1 Basic information of the study population Features Patients (n = 343) Age Mean (IQR) 46.0 (31.0-58.5) 14 ~ 25 60 (17.5) 26 ~ 40 73 (21.3) 41 ~ 60 130 (37.9) 61~ 80 (23.3) Gender (n, %) Male 215 (62.7) Female 128 (37.3) Previous TB treatment (n, %) Yes 120 (35.0) No 223 (65.0) Diabetes mellitus (n, %) Yes 27 (7.9) No 316 (92.1) Hypertension (n, %) Yes 13 (3.8) No 330 (96.2) Clinical diagnosis (n, %) PTB 274 (79.9) No-PTB 69 (20.1) Acid-fast bacilli (n, %) Positive 67 (19.5) Negative 276 (80.5) MGIT 960 culture (n, %) MTB positive 105 (30.6) MTB negative 175 (51.0) Xpert MTB/RIF (n, %) MTB positive 73 (21.3) MTB negative 147 (42.9) Nucleotide MALDI-TOF MS (n, %) MTB positive 206 (60.1) MTB negative 137 (39.9) We further compared the distribution of demographic and clinical characteristics between PTB and non-PTB patients in our study as shown in Table 2 . The ratio of patients with previous TB treatment in PTB group (37.6%) was significantly higher than those in non-PTB group (24.6%). Additionally, PTB group had a greater percentage of male subjects, although this result was not statistically significant (65.3% vs 52.2%, p = 0.051). Table 2 Comparisons between PTB patients and non-PTB patient Characteristics PTB non-PTB p value Gender (n, %) 0.051 Female 95 (34.7) 33 (47.8) Male 179 (65.3) 36 (52.2) Age (n, %) Mean (IQR) 45.3 (30.0, 58.0) 48.6 (33.0, 65.0) 0.185 14 ~ 25 50 (18.2) 10 (14.5) 0.538 26 ~ 40 61 (22.3) 12 (17.4) 41 ~ 60 103 (37.6) 27 (39.1) 61~ 60 (21.9) 20 (29.0) Pervious TB treatment (n, %) 0.048 No 171 (62.4) 52 (75.4) Yes 103 (37.6) 17 (24.6) DM (n, %) 0.620 No 251 (91.6) 65 (94.2) Yes 23 (8.4) 4 (5.8) Hypertension (n, %) 0.729 No 264 (96.4) 66 (95.7) Yes 10 (3.6) 3 (4.3) Clinical performance of nucleotide MALDI-TOF MS, smear microscopy, culture and Xpert MTB/RIF In the present study, nucleotide MALDI-TOF MS and smear microscopy were performed for all BALF samples, whereas 280 and 220 samples were conducted using MGIT 960 culture and Xpert MTB/RIF, respectively. A total of 67/343 (19.5%) patients had a positive acid-fast bacilli smear microscopy, 105/343 (30.6%) had a positive MGIT 960 culture, 73/343 (21.3%) had a positive Xpert MTB/RIF and 206/343 (60.1%) had a positive nucleotide MALDI-TOF MS assay (Table 1 ). Out of the 189 cases with results using the three diagnostic tools, namely MGIT 960 culture, Xpert MTB/RIF and nucleotide MALDI-TOF MS assay, 124 cases were MTB positive for either method. As Fig. 2 shown, 43 (34.7%, 43/124) cases were found positive for MTB by all the three methods, whereas 22 (17.7%, 22/124) were MTB positive by two methods. Additionally, 45 (36.3%, 45/124) patients were positive for MTB using MALDI-TOF MS assay exclusively, with seven (5.6%, 7/124) cases positive by Xpert MTB/RIF or culture only (Fig. 2 ). Analyses for diagnostic performance of nucleotide MALDI-TOF MS on BALF specimens Using finally clinical diagnosis as reference standard, the overall sensitivity of nucleotide MALDI-TOF MS assay was 71.5% (95%CI: 65.8–76.8%), significantly higher than that of smear microscopy (22.6%, 17.8–28.0%), MGIT 960 culture (40.6%, 34.3–47.1%) and Xpert MTB/RIF assay (40.8%, 33.5–48.4%). Meanwhile, the specificity of nucleotide MALDI-TOF MS assay was 85.5% (75. 0-92.8%), slightly lower than that of smear microscopy (92.8%, 83.9–97.6%) and Xpert MTB/RIF assay (100.00%, 91.4–100.0%), a little higher than that of MGIT 960 culture (80.5%, 65.1–91.2%). Nevertheless, no significant difference existed among those detection methods. The respective accuracy for smear microscopy, MGIT 960 culture, Xpert MTB/RIF and nucleotide MALDI-TOF MS assay were 36.7% (31.6–42.1%), 46.4% (40.5–52.5%), 51.8% (45.0-58.6%), and 74.3% (69.4–78.9%) (Table 3 ). The area under the curve (AUC) value for nucleotide MALDI-TOF MS assay was 0.800, larger than those obtained from smear microscopy (0.558), MGIT culture (0.614) and Xpert MTB/RIF (0.593) (Fig. 3 . a ). Table 3 Diagnostic performance of different methods, including smear microscopy, culture, Xpert MTB/RIF, and nucleotide MALDI-TOF MS assay on BALFs from the clinical susceptible PTB patients using clinical diagnosis as reference Test method Results of MTB Clinical diagnosis Sensitivity (%, 95%CI) Specificity (%, 95%CI) PPV (%, 95%CI) NPV (%, 95%CI) PTB (274) non-PTB (69) Smear microscopy (n = 343) Positive 62 5 22.6 (17.8–28.0) 92.8 (83.9–97.6) 92.5 (83.4–97.5) 23.2 (18.3–28.6) Negative 212 64 p < 0.001 p = 0.839 p = 0.971 p = 0.004 MGIT 960 culture (n = 280) Positive 97 8 40.6 (34.3–47.1) 80.5 (65.1–91.2) 92.4 (85.5–96.7) 18.9 (13.4–25.5) Negative 142 33 p < 0.001 p = 0.953 p = 0.932 p < 0.001 Xpert MTB/RIF (n = 220) Positive 73 0 40.8 (33.5–48.4) 100.0 (91.4–100.0) 100.0 (95.1–100.0) 27.9 (20.8–35.9) Negative 106 41 p < 0.001 p = 0.681 p = 0.872 p = 0.083 nucleotide MALDI-TOF MS (n = 343) Positive 196 10 71.5(65.8–76.8) 85.5 (75. 0-92.8) 95.1 (91.3–97.6) 43.1(34.6–51.8) Negative 78 59 ref ref ref ref Abbreviations: PTB: pulmonary tuberculosis; non-PTB: non-pulmonary tuberculosis; PPV: positive predictive value; NPV: negative predictive value; CI: confidence interval; Ref: reference. To investigate the diagnostic performance of nucleotide MALDI-TOF MS assay for the detection of MTB in BALFs from smear-negative patients, we have separately analyzed 276 samples with negative results using smear microscopy, with total of 212 cases diagnosed to be PTB. Using finally clinical diagnosis as reference standard, the sensitivity of nucleotide MALDI-TOF MS assay was 65.1% (95%CI: 58.3–71.5%), significantly higher than that of MGIT 960 culture (25.4%, 19.2–32.4%) and Xpert MTB/RIF assay (30.7%, 23.2–39.1%). The corresponding specificity of these methods was 84.4% (73.1–92.2%), 88.9% (73.9–96.9%) and 100.0%, (90.7–100.0%), respectively, without significantly differences (Table 4 ). The AUC values for nucleotide MALDI-TOF MS, MGIT 960 culture and Xpert MTB/RIF were 0.692, 0.525 and 0.562, respectively (Fig. 3 . b ). Collectively, our results indicated nucleotide MALDI-TOF MS assay exhibited better diagnostic performance on the smear-negative BALFs from suspected PTB patients. Table 4 Diagnostic performance of different methods, including culture, Xpert MTB/RIF, and nucleotide MALDI-TOF assay on BALFs from the clinical susceptible smear-negative PTB patients using clinical diagnosis as reference Test method Results of MTB Clinical diagnosis Sensitivity (%, 95%CI) Specificity (%, 95%CI) PPV (%, 95%CI) NPV (%, 95%CI) Accuracy (%, 95%CI) PTB (212) non-PTB (64) MGIT 960 culture (n = 217) Positive 46 4 25.4 (19.2–32.4) 88.9 (73.9–96.9) 92. 0 (80.8–97.8) 19.2 (13.5–26. 0) 35.9 (29.6–42.7) Negative 135 32 p 0.99 p = 0.002 p < 0.001 Xpert MTB/RIF (n = 178) Positive 43 0 30.7 (23.2–39.1) 100.0 (90.7–100.0) 100.0 (91.8–100.0) 28.1 (20.8–36.5) 45.5 (38.0-53.1) Negative 97 38 p < 0.001 p = 0.667 p = 0.872 p = 0.125 p = 0.012 nucleotide MALDI-TOF MS (n = 276) Positive 138 10 65.1 (58.3–71.5) 84.4 (73.1–92.2) 93.2 (87.9–96.7) 42.2 (33.5–51.2) 69.6 (63.8–74.9) Negative 74 54 ref ref ref ref ref Abbreviations: PTB: pulmonary tuberculosis; non-PTB: non-pulmonary tuberculosis; PPV: positive predictive value; NPV: negative predictive value; CI: confidence interval; Ref: reference. Analyses for rifampicin resistance detection of nucleotide MALDI-TOF MS on BALF specimens In order to evaluate the concordance of nucleotide MALDI-TOF MS assay and Xpert MTB/RIF for the rifampicin (RIF) resistance detection, those cases with positive results for MTB using both methods were included in the analyses. Of the 63 cases, six showed discordant results (Table 5 ). Four tests were RIF-sensitive by Xpert MTB/RIF but RIF-resistant by nucleotide MALDI-TOF MS, and the remaining two tests were vice versa, leading to the agreement of 90.5% of these two methods. Using the results of MGIT 960 culture as the references, three of cases identified as RIF-Resistant via nucleotide MALDI-TOF MS were RIF-sensitive confirmed by culture and the remaining cases were identical with those obtained from culture. Table 5 Inconsistency of Rifampicin susceptibility identified with different methods nucleotide MALDI-TOF MS Xpert MTB/RIF MGIT 960 culture confirmed Inconsistent Rifampicin susceptibility (n = 6, 9.5%) Resistant Sensitive Sensitive Sensitive Resistant Sensitive Resistant Sensitive Sensitive Resistant Sensitive Resistant Resistant Sensitive Sensitive Sensitive Resistant Sensitive Discussion In this study, the diagnostic capacity of nucleotide MALDI-TOF MS assay to detect MTB in BALFs from presumed PTB patients was evaluated and compared with conventional methods used in our hospital. Our results revealed that the performance of nucleotide MALDI-TOF MS assay was significantly superior to that of smear microscopy, MGIT 960 culture and Xpert MTB/RIF test not only on overall BALF samples but also smear-negative ones. In the present study, the diagnostic sensitivity of nucleotide MALDI-TOF MS was 71.5% for BALFs from PTB patients, whereas those of smear, culture and Xpert MTB/RIF were 22.6%, 40.6%, and 40.8%, respectively. Together, about 50% and 30% patients benefited from nucleotide MALDI-TOF MS compared with smear and culture or Xpert MTB/RIF, respectively. MALDI-TOF MS has been widely used in clinical microbiology detection for decades, with mature application for the identification of NTM based on proteins 14–17 . However, culture of mycobacteria was required if using protein-based MALDI-TOF MS assay, providing great advantages for fast-growing mycobacteria, while rapid detection of slow-growing mycobacteria, such as MTB, cannot be achieved. Nucleotide MALDI-TOF MS assay, using nucleic acids as substrates, can solve this above problem by targeting specific nucleotide polymorphisms. In 2017, a research study from Taiwan demonstrated that the detection limit of nucleotide MALDI-TOF MS assay on mycobacterial species identification was as low as 5 copies, with well-performed sensitivity and specificity of drug resistant detection 18 . Wu et al., have evaluated the prediction of MTB drug resistance with nucleotide MALDI-TOF MS, using phenotype drug resistance as reference and showed that it could be a promising tool for rapid detection of drug resistance 11 . Nevertheless, the evaluation was conducted on the culture samples of MTB instead of clinical samples directly. Although it is featured with high throughput, speed, sensitivity, high accuracy and low cost, investigations on the application of nucleotide MALDI-TOF MS assay for PTB diagnosis in real world are still extremely limited and more research data are needed for support. To this end, we conducted this retrospective study to evaluate the diagnostic performance of nucleotide MALDI-TOF MS assay on BALFs from suspected PTB patients in Southwestern region of China with relatively large sample size. Li et al. and Yang et al. have published similar articles with very small sample size (37 and 52 BALFs respectively), likely resulting in big bias 19,20 . The results of various methods in their study were generally higher than those obtained from our study. The influential factors among them may be various other than the sample size, such as study site, the experimental operators. BALF is the most common used respiratory sample type for the diagnosis of PTB besides sputum, which is also preferred by clinicians due to its closer proximity to the lesion. Multiple studies have reported the capability of different molecular tests to diagnose PTB in BALFs, such as Xpert MTB/RIF assay, SAT-TB, LAMP, next-generation metagenome sequencing, nanopore sequencing, etc., with sensitivities raging from 45.18–94.4% 21–26 . The comparatively lower results of the Xpert MTB/RIF assay in our study than those previously studies may be related to several factors, including study site, sample source, and the operator, suggesting that we need to improve the level of testing within our hospital. On the other hand, it is essential to emphasize the acquisition of high-quality specimens, since this often determines the final yield. Jiang et al., have demonstrated that attention to sputum quality can significantly increase bacteriological confirmation 27 . None the less, the very recent published study also showed a low sensitivity of Xpert MTB/RIF assay on BALFs to be 34.78%, lower than ours 28 . We can also assess the impact of BALF quality on bacteriological confirmation in the future. In our study, 14 cases were found to be nucleotide MALDI-TOF MS assay-negative but culture-positive. Finally, eight of them (57.1%) were clinically diagnosed with PTB and others were diagnosed with non-PTB. These false negatives may be due to insufficient nucleic acid or PCR inhibitors in BALFs 29 . On the other hand, 85 patients were found to be nucleotide MALDI-TOF MS assay-positive but culture-negative, 83 of which were diagnosed with PTB. This occurred might have several reasons. First, positive culture required live bacilli and the treatment history of patients might lead to negative cultures. Second, successful cultures require various factors including reagents, instruments, storage and expertise in operation 30 . In terms of the turnaround time of MGIT 960 culture and nucleotide MALDI-TOF MS assay, the detection time of results obtained from culture in our hospital ranged from 14 to 50 days where less than one day for nucleotide MALDI-TOF MS assay. We here also analyzed the consistency of nucleotide MALDI-TOF MS assay and Xpert MTB/RIF for rifampicin sensitivity with a good agreement between the two assays. Rifampicin susceptibility culture results using MGIT 960 system, were all available for the six discordant samples. We observed that all samples discordant with culture results were RIF-resistant using nucleotide MALDI-TOF MS assay. Several reasons might be responsible for this inconsistence. MGIT 960 drug susceptibility testing was prone to yield false sensitive results for samples with minimal inhibitory concentrations (MICs) for rifampicin close to cut-off value 31 . Heteroresistance should also be considered as a factor that might influence the outcomes since nucleotide MALDI-TOF MS assay has ability to detect low-level heterogeneous drug resistance with the limit of 0.1% 32 . Certainly, technical errors of nucleotide MALDI-TOF MS assay leading to false resistance cannot be ruled out, after all, the results of the other two methods were consistent. Our study has several limitations. First, it was a retrospectively study conducted at a single center. We couldn’t control several factors appeared in this study, such as not all of samples were conducted using culture or Xpert MTB/RIF assay. In order to obtain much more precise evaluation of performance of nucleotide MALDI-TOF MS assay, prospective and multicenter studies should be designed in future. Second, smear microscopy and nucleotide MALDI-TOF MS assay were performed on all of the samples, whereas MGIT 960 culture and Xpert MTB/RIF were not always done, thus resulting in some biases because of the missing data. Third, bronchoscopy was invasive and not acceptable to all patients, which was performed after carefully considered to be necessary to obtain BALFs, such as a high suspicion of PTB. This resulted in the majority of enrolled patients diagnosed as PTB, with bias in terms of specificity. Finally, in terms of the inconsistent samples for rifampicin susceptibility identified with nucleotide MALDI-TOF MS and Xpert MTB/RIF, we didn’t perform sequencing to further validate. Conclusion In summary, this study has shown nucleotide MALDI-TOF MS assay of BALFs is an accurate tool for the early diagnosis of PTB with high sensitivity and comparable specificity, which can provide more effective guidance for the treatment of PTB. Declarations Acknowledgments The authors acknowledged the staff at Chongqing Tuberculosis Control Institute, Chongqing Public Health Medical Center. This research was funded by Chongqing medical scientific research project, grant number 2023MSXM0321. Author Contributions Conceptualization, Ling Jiang and Tongxin Li; Data curation, Tongxin Li; Formal analysis, Lijun Liang and Mingqiang Xia; Funding acquisition, Ling Jiang; Investigation, Mingqiang Xia and Jiyao Li; Methodology, Lijun Liang, Mingqiang Xia, Jiyao Li, Junqiu Xin, Jingfeng Tong and Chengchen Huang; Resources, Tongxin Li; Software, Jingfeng Tong and Chengchen Huang; Supervision, Tongxin Li; Validation, Ling Jiang and Tongxin Li; Writing – original draft, Ling Jiang and Junqiu Xin; Writing – review & editing, Tongxin Li. All authors have read and agreed to the published version of the manuscript. Competing interests The authors have no competing interests to declare. Data availability All the data and material were true and available. The data is available from the corresponding author upon reasonable request. Ethics declarations The study protocol was approved by the Ethics Committee of Chongqing Public Health Medical Center of China (2023-013). The requirement of written informed consent was waived owing to the retrospective study design with approval from the Research Ethics Committee of the study hospital. References World Health Organization. Global tuberculosis report 2022. Geneva ： World Health Organization (2022). Van Cutsem, G. et al. Infection Control for Drug-Resistant Tuberculosis: Early Diagnosis and Treatment Is the Key. Clinical Infectious Diseases 62 , S238–S243 (2016). YOSHIDA, S., TSUYUGUCHI, K., KOBAYASHI, T., SHIMATANI, Y. & INOUE, Y. Effect of sputum quality on Mycobacterium avium-intracellulare complex lung disease diagnosis and treatment initiation according to disease type. 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Evaluation of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Nontuberculous Mycobacteria from Clinical Isolates. J Clin Microbiol 53 , 2737–2740 (2015). Su, K. Y. et al. Rapid Sputum Multiplex Detection of the M. tuberculosis Complex (MTBC) and Resistance Mutations for Eight Antibiotics by Nucleotide MALDI-TOF MS. Sci Rep 7 , 1–10 (2017). Li, B. et al. Performance evaluation and clinical validation of optimized nucleotide MALDI-TOF-MS for mycobacterial identification. Front Cell Infect Microbiol 12 , (2022). Yang, H. et al. A rapid, accurate, and low-cost method for detecting Mycobacterium tuberculosis and its drug-resistant genes in pulmonary tuberculosis: Applications of MassARRAY DNA mass spectrometry. Front Microbiol 14 , (2023). Bai, W. et al. Assessing the utility of the Xpert Mycobacterium tuberculosis/rifampin assay for analysis of bronchoalveolar lavage fluid in patients with suspected pulmonary tuberculosis. J Clin Lab Anal 36 , (2022). Fan, L. et al. A Comprehensive Evaluation of a Loop-Mediated Isothermal Amplification Assay for the Diagnosis of Pulmonary Tuberculosis in Children Using Bronchoalveolar Lavage Fluid. Infect Drug Resist 15 , 975–987 (2022). Wu, Z. et al. The Diagnostic Value of the Thermostatic Amplification of Ribonucleic Acid in Bronchoalveolar Lavage Fluid in Smear-Negative Pulmonary Tuberculosis. Front Public Health 10 , (2022). Xu, P. et al. Next-Generation Metagenome Sequencing Shows Superior Diagnostic Performance in Acid-Fast Staining Sputum Smear-Negative Pulmonary Tuberculosis and Non-tuberculous Mycobacterial Pulmonary Disease. Front Microbiol 13 , (2022). Zhu, N., Zhou, D. & Li, S. Diagnostic Accuracy of Metagenomic Next-Generation Sequencing in Sputum-Scarce or Smear-Negative Cases with Suspected Pulmonary Tuberculosis. Biomed Res Int 2021 , (2021). Liu, Z. et al. Diagnostic value of a nanopore sequencing assay of bronchoalveolar lavage fluid in pulmonary tuberculosis. BMC Pulm Med 23 , 77 (2023). Jiang, Q. et al. A randomised controlled trial of stepwise sputum collection to increase yields of confirmed tuberculosis. International Journal of Tuberculosis and Lung Disease 23 , 685–691 (2019). Cao, J. et al. EBUS-GS with the GeneXpert MTB/RIF assay for diagnosis of Mycobacterium tuberculosis infection of isolated pulmonary nodules. Eur J Med Res 28 , 370 (2023). Meyer, A. J. et al. Sputum quality and diagnostic performance of GeneXpert MTB/RIF among smear-negative adults with presumed tuberculosis in Uganda. PLoS One 12 , (2017). Luo, J. et al. Biological interpretation of the sporadic sputum smear-positive-culture-negative outcome for patients with tuberculosis undertaking treatments. Front Public Health 11 , (2023). Bokop, C., Faye, L. M. & Apalata, T. Analysis of Discordance between Genotypic and Phenotypic Assays for Rifampicin-Resistant Mycobacterium tuberculosis Isolated from Healthcare Facilities in Mthatha. Pathogens 12 , 909 (2023). Mosko, M. J. et al. Ultrasensitive Detection of Multiplexed Somatic Mutations Using MALDI-TOF Mass Spectrometry. Journal of Molecular Diagnostics 18 , 23–31 (2016). Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4014901","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":281725674,"identity":"be0247cc-7052-4a9a-b600-908f347f5d29","order_by":0,"name":"Ling Jiang","email":"","orcid":"","institution":"Chongqing Public Health Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Ling","middleName":"","lastName":"Jiang","suffix":""},{"id":281725675,"identity":"6930a355-6bc3-442f-954f-951b1f9f6f80","order_by":1,"name":"Junqiu Xin","email":"","orcid":"","institution":"Chongqing Public Health Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Junqiu","middleName":"","lastName":"Xin","suffix":""},{"id":281725676,"identity":"335c4507-74b4-4e7f-a5bc-a285dfc2a7f4","order_by":2,"name":"Lijun Liang","email":"","orcid":"","institution":"Chongqing Public Health Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Lijun","middleName":"","lastName":"Liang","suffix":""},{"id":281725677,"identity":"477ba1d2-a99c-4e93-b84f-e141ef0cd7c0","order_by":3,"name":"Mingqiang Xia","email":"","orcid":"","institution":"Chongqing Public Health Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Mingqiang","middleName":"","lastName":"Xia","suffix":""},{"id":281725678,"identity":"d018a56e-6183-4bd4-94ca-da8b86639ef2","order_by":4,"name":"Jiyao Li","email":"","orcid":"","institution":"Chongqing Public Health Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Jiyao","middleName":"","lastName":"Li","suffix":""},{"id":281725679,"identity":"67e15a2a-4221-4ca8-b6ab-f87586acdb63","order_by":5,"name":"Jingfeng Tong","email":"","orcid":"","institution":"Shanghai Conlight Medical Co., Ltd","correspondingAuthor":false,"prefix":"","firstName":"Jingfeng","middleName":"","lastName":"Tong","suffix":""},{"id":281725680,"identity":"401e1605-07ae-4793-afa4-f9a10de3c2c1","order_by":6,"name":"Chengchen Huang","email":"","orcid":"","institution":"Shanghai Conlight Medical Co., Ltd","correspondingAuthor":false,"prefix":"","firstName":"Chengchen","middleName":"","lastName":"Huang","suffix":""},{"id":281725681,"identity":"6c7353f9-2578-443f-ae13-3cb3bd020dcd","order_by":7,"name":"Li tongxin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIie3PO2rEMBCAYZkBqfFG7RiH3StICPKocpUxhq2WNGlcmERgcK6wRcgxtpYbp9EBXNoJpE4bEkJ8gMXKdin0FarmRzOMRdE/dAbzQ1UNNw1040eF600o4TA3o++FEm2p9/7KaBtKGLBkakGq1F/kq7YqmAslQvZInOeXuCVcPSMlFqbXYXkxUJSem+t96VR2wFvBuDG75SQZCXnJhi2RPuBdYlOeBxLmSMGDHXbKFU9YWBdO5l9o3s57bTv7t8Qocj1kj22Z2B6NbgK3SNm9Z58/NUiAl6/v+n69Ec30tpQcAaeNR1EURUf8AlvSRT66DdP+AAAAAElFTkSuQmCC","orcid":"","institution":"Chongqing Public Health Medical Center","correspondingAuthor":true,"prefix":"","firstName":"Li","middleName":"","lastName":"tongxin","suffix":""}],"badges":[],"createdAt":"2024-03-05 02:33:44","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4014901/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4014901/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-024-66178-8","type":"published","date":"2024-08-08T15:58:09+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":53196689,"identity":"b1c22e50-f5cb-4485-8de8-89f07ab733b8","added_by":"auto","created_at":"2024-03-21 18:34:30","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":74923,"visible":true,"origin":"","legend":"\u003cp\u003eFlow diagram of the study population\u003c/p\u003e","description":"","filename":"Figure1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4014901/v1/e3f0ed8bb241185bb3581f6d.jpeg"},{"id":53196690,"identity":"0fee9095-1b8e-44ef-82f0-537fcf517218","added_by":"auto","created_at":"2024-03-21 18:34:30","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":21767,"visible":true,"origin":"","legend":"\u003cp\u003eVenn diagram depicting the overlapping test results for MTB positive by either of the three methods, namely MGIT 960 culture, Xpert MTB/RIF, and nucleotide MALDI-TOF MS assays\u003c/p\u003e","description":"","filename":"Figure2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4014901/v1/1a8cec7dff9d92eadedb4f79.jpeg"},{"id":53196691,"identity":"01833816-3fe5-4bfa-8742-b4f0f7777517","added_by":"auto","created_at":"2024-03-21 18:34:30","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":57723,"visible":true,"origin":"","legend":"\u003cp\u003eThe diagnostic accuracy of different detection techniques on BALF samples. (\u003cstrong\u003ea\u003c/strong\u003e) The ROCs of nucleotide MALDI-TOF MS assay, Xpert MTB/RIF, Smear microscopy, and MGIT 960 culture on all of BALF samples with AUC to be 0.800, 0.687, 0.558, and 0.614, respectively. (\u003cstrong\u003eb\u003c/strong\u003e) The ROCs of nucleotide MALDI-TOF MS assay, Xpert MTB/RIF, and MGIT 960 culture on smear-negative BALF samples with AUC to be 0.776, 0.652 and 0.586, respectively\u003c/p\u003e","description":"","filename":"Figure3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4014901/v1/7b409bf7ab7a52a721024d93.jpeg"},{"id":62299272,"identity":"db946f6d-9dab-47ff-9ab9-0fb087c8d904","added_by":"auto","created_at":"2024-08-12 16:18:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1027946,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4014901/v1/5e04e756-72ce-43cd-872a-1924c561350b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Evaluation of nucleotide MALDI-TOF MS on bronchoalveolar lavage fluid for pulmonary Tuberculosis: experience from a tertiary hospital in southwestern China","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTuberculosis (TB), a communicable disease mainly due to infection with \u003cem\u003eMycobacterium tuberculosis\u003c/em\u003e (MTB), remains a major public health problem that afflicts approximately 10\u0026nbsp;million people worldwide, of which, pulmonary tuberculosis (PTB) is the most common form\u003csup\u003e1\u003c/sup\u003e. Early PTB diagnosis and initial proper treatment are crucial for the prevention of disease progression\u003csup\u003e2\u003c/sup\u003e. Microbiological tests based on high-quality respiratory specimens are essential to enable accurate diagnosis of PTB. Sputum specimens are the most common type; however, the quality of them is difficult to ensure, especially in patients who unable to self-expectorate or have no sputum\u003csup\u003e3,4\u003c/sup\u003e. Alternatively, bronchoalveolar lavage fluid (BALF) is another sample type to be considered and favoured by physicians\u003csup\u003e5\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eCurrently, standard PTB microbiologically diagnostic methods in most hospitals usually include smear microscopy, culture, each with its own strengths and weaknesses \u003csup\u003e6\u003c/sup\u003e. Smear microscopy provides the advantage of speed, yet its sensitivity is insufficient nor can it differentiate MTB and nontuberculous mycobacteria (NTM). The culture method, including Mycobacterium Growth Indicator Tube 960 culture (MGIT 960 culture), remains the gold standard for the diagnosis of TB, but it demands high-level biosafety, high personnel expertise, poses risks of fragile contamination and most importantly has long turnaround time\u003csup\u003e7\u003c/sup\u003e, resulting the delayed diagnosis and potential drug resistance\u003csup\u003e8\u003c/sup\u003e. With the development of molecular technology, many methods for the rapid diagnosis of TB occur recent years, several of which have been recommended by the World Health Organization (WHO), like Xpert MTB/RIF assay, the first approved one \u003csup\u003e9\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eNucleotide MALDI-TOF MS assay, a relative novel technology, is matrix-assisted laser desorption ionization time-of-flight mass spectrometry based on nucleotide, possessing the advantages of rapidity, high throughput and high accuracy \u003csup\u003e10\u003c/sup\u003e. Several studies have demonstrated the promising application of this technique in TB diagnosis and its drug resistance \u003csup\u003e11,12\u003c/sup\u003e; however, evaluation of this assay using BALF specimens in more real-world practices and different regions in China remains very limited. Here, we analysed the diagnostic performance of nucleotide MALDI-TOF MS assay on BALFs obtained from highly suspected PTB patients in southwestern region of China and compared the results to those of smear microscopy, MGIT 960 culture and Xpert MTB/RIF assay. Thus, we hope that the results of this study will contribute to the improvement of the clinic diagnosis of PTB.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eParticipants and Clinical Diagnosis\u003c/h2\u003e \u003cp\u003e We retrospectively reviewed the clinical and laboratory test results of patients with suspected PTB who underwent nucleotide MALDI-TOF MS assay on BALFs from May 2021 to January 2022 at Chongqing Public Health Medical Center (Chongqing, China), a tertiary TB designated hospital lacated at in Southwest China. Medical data were collected, including age, sex, previous TB treatment, clinical diagnosis, and comorbidities. We have no access to information that could identify individual participants during or after data collection. During this time, a total of 343 patients agreed to conduct nucleotide MALDI-TOF assay on BALFs. These samples were subjected to acid-fast bacilli smear microscopy, culture or the Xpert MTB/RIF assay. However, not all of these BALF samples were performed using culture or Xpert MTB/RIF assay; that is, 280 for MGIT 960 culture and 220 for Xpert MTB/RIF.\u003c/p\u003e \u003cp\u003e Clinically diagnosed PTB cases were diagnosed based on the guidelines of ATS/CDC/IDSA and the Health Industry Standards of the People\u0026rsquo;s Republic of China Diagnosis of Tuberculosis (WS 288\u0026ndash;2017). A patient diagnosed with confirmed PTB had one or more of the following criteria: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) positive microbiological results based on culture or molecular tests of sputum, BALF, or puncture fluid; (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) positive results for MTB based on histopathological examination of puncture, biopsy, or surgical samples; and (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) improved symptoms after anti-TB treatment. Otherwise, cases were classified as non-PTB patients. A positive microbiological result was defined as any positive evidence of MTB detected in any sample provided by the patient admitted to our center, including BLAF, sputum, or puncture fluid samples, according to culture or Xpert MTB/RIF assay and regardless of the results of nucleotide MALDI-TOF MS assay.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eBALF collection\u003c/h2\u003e \u003cp\u003e Bronchoscopy was performed according to the Chinese Thoracic Society expert consensus. To collect BALF, 50\u0026thinsp;~\u0026thinsp;100 mL of isotonic saline was used for bronchial washing of the related sub-segment and 5\u0026ndash;20 mL of the recovered BALFs were collected into the sterile containers and sealed. The containers were delivered immediately to the laboratory for smear microscopy, culture or Xpert MTB/RIF assay and nucleotide MALDI-TOF MS assay.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eConventional test methods for BALF specimens\u003c/h2\u003e \u003cp\u003eThe collected BALF samples were subjected for traditional test in our hospital as follows: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) Acid-fast bacillus microscopy: The samples were liquefied and centrifuged to obtain a precipitate. The sediment was spread onto the front of a glass microscope slide, which was allowed to air dry and heat-fixed before staining with the Ziehl-Neelsen method. Smear results of 1\u0026thinsp;+\u0026thinsp;or more acid-fast bacillus (AFB) were recorded as positive for statistical analysis. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) MGIT 960 culture: The Mycobacteria Growth Indicator Tube (MGIT) 960 system (BD Diagnostics) was used for liquid culture. All samples were inoculated in the MGIT tubes were incubated in the corresponding instrument. (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) Xpert MTB/RIF assay: The testing was performed according to the manufacturer\u0026rsquo;s instructions (Cepheid, USA).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eNucleotide MALDI-TOF MS assay\u003c/h2\u003e \u003cp\u003eThe assay used Conlight TB\u0026amp;DR\u0026reg; assay, which was well-established and conducted by Shanghai Conlight Medical Co., Ltd. This assay integrates the sensitivity of PCR technology and the high throughput nature of mass spectrometry detection technology. One reaction can amplify up to 40 gene amplifications that can applied to single nucleotide polymorphism analysis, mutant detection, and other research areas. The specific procedures can be found in the literatures \u003csup\u003e11,13\u003c/sup\u003e. Briefly, the process includes the following six steps: extraction of nucleic acids from samples, PCR to obtain target fragments, shrimp alkaline phosphatase (SAP) reaction, extension reaction, detection on the MS instrument, and automatic analysis of results by MassARRAY analysis software.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eAll information of patients enrolled in the study were recorded in EXCEL. R 4.2.0 was used for statistical analysis. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with 95% confidence intervals (95% CI) were calculated. Chi-squared test was used for the comparison of indicators obtained from various methods. Receiver operating characteristic (ROC) curves and their areas under the curve (AUC) were used to evaluate the diagnostic accuracy. A two-tailed value of \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered as statistical significance.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eEthics statement\u003c/h2\u003e \u003cp\u003e The study protocol was approved by the Ethics Committee of Chongqing Public Health Medical Center of China (2023-013). This study was conducted in accordance with the principles of the Declaration of Helsinki of the World Medical Association and with Good Clinical Practice Guidelines.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n\u003ch2\u003eBasic information of the enrolled participants\u003c/h2\u003e\n\u003cp\u003eAs shown in the flow chart (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e), we retrospectively screened suspected PTB cases who visited Chongqing Public Health Medical Center between May 2021 and January 2022 and found a total of 343 cases agreed to undergo nucleotide MALDI-TOF MS assay, which were enrolled in this study. BALF samples were obtained from all patients and subjected to nucleotide MALDI-TOF MS assay. At same time, routine laboratory tests were performed in our hospital as follows: all samples underwent smear microscopy, 280 of them were cultured on MGIT 960 system, and 220 were analyzed with Xpert MTB/RIF assay. Clinical diagnosis of PTB was finally made in 274 cases (79.9%) and the remaining (69, 20.1%) was classified as non-PTB patients.\u003c/p\u003e\n\u003cp\u003eDemographic and clinical features of the study population were presented in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. Of the enrolled participants, 215 (62.7%) were males and 128 (37.3%) were females, with a median age of 46.0 years (interquartile range [IQR]: 31.0-58.5). Twenty-seven patients (7.9%) were diagnosed with diabetes mellitus (DM), 13 patients (3.8%) with hypertension, and 120 patients (35.0%) with a history of TB treatment.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eBasic information of the study population\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFeatures\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePatients (n\u0026thinsp;=\u0026thinsp;343)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eAge\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMean (IQR)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e46.0 (31.0-58.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e14\u0026thinsp;~\u0026thinsp;25\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e60 (17.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26\u0026thinsp;~\u0026thinsp;40\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e73 (21.3)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e41\u0026thinsp;~\u0026thinsp;60\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e130 (37.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e61~\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e80 (23.3)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eGender (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMale\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e215 (62.7)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eFemale\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e128 (37.3)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003ePrevious TB treatment (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e120 (35.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e223 (65.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eDiabetes mellitus (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e27 (7.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e316 (92.1)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eHypertension (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e13 (3.8)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e330 (96.2)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eClinical diagnosis (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePTB\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e274 (79.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNo-PTB\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e69 (20.1)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eAcid-fast bacilli (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePositive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e67 (19.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNegative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e276 (80.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eMGIT 960 culture (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMTB positive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e105 (30.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMTB negative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e175 (51.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eXpert MTB/RIF (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMTB positive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e73 (21.3)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMTB negative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e147 (42.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eNucleotide MALDI-TOF MS (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMTB positive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e206 (60.1)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMTB negative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e137 (39.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eWe further compared the distribution of demographic and clinical characteristics between PTB and non-PTB patients in our study as shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. The ratio of patients with previous TB treatment in PTB group (37.6%) was significantly higher than those in non-PTB group (24.6%). Additionally, PTB group had a greater percentage of male subjects, although this result was not statistically significant (65.3% vs 52.2%, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.051).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eComparisons between PTB patients and non-PTB patient\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eCharacteristics\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePTB\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003enon-PTB\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eGender (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.051\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eFemale\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e95 (34.7)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e33 (47.8)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMale\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e179 (65.3)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e36 (52.2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eAge (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMean (IQR)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e45.3 (30.0, 58.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e48.6 (33.0, 65.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.185\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e14\u0026thinsp;~\u0026thinsp;25\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e50 (18.2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e10 (14.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.538\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26\u0026thinsp;~\u0026thinsp;40\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e61 (22.3)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e12 (17.4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e41\u0026thinsp;~\u0026thinsp;60\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e103 (37.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e27 (39.1)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e61~\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e60 (21.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e20 (29.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003ePervious TB treatment (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e0.048\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e171 (62.4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e52 (75.4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e103 (37.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e17 (24.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eDM (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.620\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e251 (91.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e65 (94.2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e23 (8.4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e4 (5.8)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eHypertension (n, %)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.729\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNo\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e264 (96.4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e66 (95.7)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eYes\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e10 (3.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e3 (4.3)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n\u003ch2\u003eClinical performance of nucleotide MALDI-TOF MS, smear microscopy, culture and Xpert MTB/RIF\u003c/h2\u003e\n\u003cp\u003eIn the present study, nucleotide MALDI-TOF MS and smear microscopy were performed for all BALF samples, whereas 280 and 220 samples were conducted using MGIT 960 culture and Xpert MTB/RIF, respectively. A total of 67/343 (19.5%) patients had a positive acid-fast bacilli smear microscopy, 105/343 (30.6%) had a positive MGIT 960 culture, 73/343 (21.3%) had a positive Xpert MTB/RIF and 206/343 (60.1%) had a positive nucleotide MALDI-TOF MS assay (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). Out of the 189 cases with results using the three diagnostic tools, namely MGIT 960 culture, Xpert MTB/RIF and nucleotide MALDI-TOF MS assay, 124 cases were MTB positive for either method. As Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e shown, 43 (34.7%, 43/124) cases were found positive for MTB by all the three methods, whereas 22 (17.7%, 22/124) were MTB positive by two methods. Additionally, 45 (36.3%, 45/124) patients were positive for MTB using MALDI-TOF MS assay exclusively, with seven (5.6%, 7/124) cases positive by Xpert MTB/RIF or culture only (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n\u003ch2\u003eAnalyses for diagnostic performance of nucleotide MALDI-TOF MS on BALF specimens\u003c/h2\u003e\n\u003cp\u003eUsing finally clinical diagnosis as reference standard, the overall sensitivity of nucleotide MALDI-TOF MS assay was 71.5% (95%CI: 65.8\u0026ndash;76.8%), significantly higher than that of smear microscopy (22.6%, 17.8\u0026ndash;28.0%), MGIT 960 culture (40.6%, 34.3\u0026ndash;47.1%) and Xpert MTB/RIF assay (40.8%, 33.5\u0026ndash;48.4%). Meanwhile, the specificity of nucleotide MALDI-TOF MS assay was 85.5% (75. 0-92.8%), slightly lower than that of smear microscopy (92.8%, 83.9\u0026ndash;97.6%) and Xpert MTB/RIF assay (100.00%, 91.4\u0026ndash;100.0%), a little higher than that of MGIT 960 culture (80.5%, 65.1\u0026ndash;91.2%). Nevertheless, no significant difference existed among those detection methods. The respective accuracy for smear microscopy, MGIT 960 culture, Xpert MTB/RIF and nucleotide MALDI-TOF MS assay were 36.7% (31.6\u0026ndash;42.1%), 46.4% (40.5\u0026ndash;52.5%), 51.8% (45.0-58.6%), and 74.3% (69.4\u0026ndash;78.9%) (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). The area under the curve (AUC) value for nucleotide MALDI-TOF MS assay was 0.800, larger than those obtained from smear microscopy (0.558), MGIT culture (0.614) and Xpert MTB/RIF (0.593) (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e. \u003cstrong\u003ea\u003c/strong\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab3\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eDiagnostic performance of different methods, including smear microscopy, culture, Xpert MTB/RIF, and nucleotide MALDI-TOF MS assay on BALFs from the clinical susceptible PTB patients using clinical diagnosis as reference\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eTest method\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eResults of MTB\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eClinical diagnosis\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eSensitivity (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eSpecificity (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003ePPV (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eNPV (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePTB (274)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003enon-PTB (69)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eSmear microscopy (n\u0026thinsp;=\u0026thinsp;343)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePositive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e62\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e5\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e22.6 (17.8\u0026ndash;28.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e92.8 (83.9\u0026ndash;97.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e92.5 (83.4\u0026ndash;97.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e23.2 (18.3\u0026ndash;28.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNegative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e212\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e64\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.839\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.971\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.004\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eMGIT 960 culture (n\u0026thinsp;=\u0026thinsp;280)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePositive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e97\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e8\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e40.6 (34.3\u0026ndash;47.1)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e80.5 (65.1\u0026ndash;91.2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e92.4 (85.5\u0026ndash;96.7)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e18.9 (13.4\u0026ndash;25.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNegative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e142\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e33\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.953\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.932\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eXpert MTB/RIF (n\u0026thinsp;=\u0026thinsp;220)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePositive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e73\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e40.8 (33.5\u0026ndash;48.4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e100.0 (91.4\u0026ndash;100.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e100.0 (95.1\u0026ndash;100.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e27.9 (20.8\u0026ndash;35.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNegative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e106\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e41\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.681\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.872\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.083\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003enucleotide MALDI-TOF MS (n\u0026thinsp;=\u0026thinsp;343)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePositive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e196\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e10\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e71.5(65.8\u0026ndash;76.8)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e85.5 (75. 0-92.8)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e95.1 (91.3\u0026ndash;97.6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e43.1(34.6\u0026ndash;51.8)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNegative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e78\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e59\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"8\"\u003eAbbreviations: PTB: pulmonary tuberculosis; non-PTB: non-pulmonary tuberculosis; PPV: positive predictive value; NPV: negative predictive value; CI: confidence interval; Ref: reference.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eTo investigate the diagnostic performance of nucleotide MALDI-TOF MS assay for the detection of MTB in BALFs from smear-negative patients, we have separately analyzed 276 samples with negative results using smear microscopy, with total of 212 cases diagnosed to be PTB. Using finally clinical diagnosis as reference standard, the sensitivity of nucleotide MALDI-TOF MS assay was 65.1% (95%CI: 58.3\u0026ndash;71.5%), significantly higher than that of MGIT 960 culture (25.4%, 19.2\u0026ndash;32.4%) and Xpert MTB/RIF assay (30.7%, 23.2\u0026ndash;39.1%). The corresponding specificity of these methods was 84.4% (73.1\u0026ndash;92.2%), 88.9% (73.9\u0026ndash;96.9%) and 100.0%, (90.7\u0026ndash;100.0%), respectively, without significantly differences (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). The AUC values for nucleotide MALDI-TOF MS, MGIT 960 culture and Xpert MTB/RIF were 0.692, 0.525 and 0.562, respectively (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e. \u003cstrong\u003eb\u003c/strong\u003e). Collectively, our results indicated nucleotide MALDI-TOF MS assay exhibited better diagnostic performance on the smear-negative BALFs from suspected PTB patients.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab4\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eDiagnostic performance of different methods, including culture, Xpert MTB/RIF, and nucleotide MALDI-TOF assay on BALFs from the clinical susceptible smear-negative PTB patients using clinical diagnosis as reference\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eTest method\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eResults of MTB\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eClinical diagnosis\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eSensitivity (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eSpecificity (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003ePPV (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eNPV (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eAccuracy (%, 95%CI)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePTB (212)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003enon-PTB (64)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eMGIT 960 culture (n\u0026thinsp;=\u0026thinsp;217)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePositive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e46\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e25.4 (19.2\u0026ndash;32.4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e88.9 (73.9\u0026ndash;96.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e92. 0 (80.8\u0026ndash;97.8)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e19.2 (13.5\u0026ndash;26. 0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e35.9 (29.6\u0026ndash;42.7)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNegative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e135\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e32\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.986\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.99\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eXpert MTB/RIF (n\u0026thinsp;=\u0026thinsp;178)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePositive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e43\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e30.7 (23.2\u0026ndash;39.1)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e100.0 (90.7\u0026ndash;100.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e100.0 (91.8\u0026ndash;100.0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e28.1 (20.8\u0026ndash;36.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e45.5 (38.0-53.1)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNegative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e97\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e38\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.667\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.872\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.125\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.012\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003enucleotide MALDI-TOF MS (n\u0026thinsp;=\u0026thinsp;276)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePositive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e138\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e10\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e65.1 (58.3\u0026ndash;71.5)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e84.4 (73.1\u0026ndash;92.2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e93.2 (87.9\u0026ndash;96.7)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e42.2 (33.5\u0026ndash;51.2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e69.6 (63.8\u0026ndash;74.9)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNegative\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e74\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e54\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eref\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"9\"\u003eAbbreviations: PTB: pulmonary tuberculosis; non-PTB: non-pulmonary tuberculosis; PPV: positive predictive value; NPV: negative predictive value; CI: confidence interval; Ref: reference.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n\u003ch2\u003eAnalyses for rifampicin resistance detection of nucleotide MALDI-TOF MS on BALF specimens\u003c/h2\u003e\n\u003cp\u003eIn order to evaluate the concordance of nucleotide MALDI-TOF MS assay and Xpert MTB/RIF for the rifampicin (RIF) resistance detection, those cases with positive results for MTB using both methods were included in the analyses. Of the 63 cases, six showed discordant results (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). Four tests were RIF-sensitive by Xpert MTB/RIF but RIF-resistant by nucleotide MALDI-TOF MS, and the remaining two tests were vice versa, leading to the agreement of 90.5% of these two methods. Using the results of MGIT 960 culture as the references, three of cases identified as RIF-Resistant via nucleotide MALDI-TOF MS were RIF-sensitive confirmed by culture and the remaining cases were identical with those obtained from culture.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab5\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eInconsistency of Rifampicin susceptibility identified with different methods\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003enucleotide MALDI-TOF MS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eXpert MTB/RIF\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eMGIT 960 culture confirmed\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"6\" align=\"left\"\u003e\n\u003cp\u003eInconsistent Rifampicin susceptibility (n\u0026thinsp;=\u0026thinsp;6, 9.5%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eResistant\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eResistant\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eResistant\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eResistant\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eSensitive\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eResistant\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eResistant\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eResistant\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSensitive\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, the diagnostic capacity of nucleotide MALDI-TOF MS assay to detect MTB in BALFs from presumed PTB patients was evaluated and compared with conventional methods used in our hospital. Our results revealed that the performance of nucleotide MALDI-TOF MS assay was significantly superior to that of smear microscopy, MGIT 960 culture and Xpert MTB/RIF test not only on overall BALF samples but also smear-negative ones. In the present study, the diagnostic sensitivity of nucleotide MALDI-TOF MS was 71.5% for BALFs from PTB patients, whereas those of smear, culture and Xpert MTB/RIF were 22.6%, 40.6%, and 40.8%, respectively. Together, about 50% and 30% patients benefited from nucleotide MALDI-TOF MS compared with smear and culture or Xpert MTB/RIF, respectively.\u003c/p\u003e \u003cp\u003eMALDI-TOF MS has been widely used in clinical microbiology detection for decades, with mature application for the identification of NTM based on proteins\u003csup\u003e14\u0026ndash;17\u003c/sup\u003e. However, culture of mycobacteria was required if using protein-based MALDI-TOF MS assay, providing great advantages for fast-growing mycobacteria, while rapid detection of slow-growing mycobacteria, such as MTB, cannot be achieved. Nucleotide MALDI-TOF MS assay, using nucleic acids as substrates, can solve this above problem by targeting specific nucleotide polymorphisms. In 2017, a research study from Taiwan demonstrated that the detection limit of nucleotide MALDI-TOF MS assay on mycobacterial species identification was as low as 5 copies, with well-performed sensitivity and specificity of drug resistant detection\u003csup\u003e18\u003c/sup\u003e. Wu et al., have evaluated the prediction of MTB drug resistance with nucleotide MALDI-TOF MS, using phenotype drug resistance as reference and showed that it could be a promising tool for rapid detection of drug resistance \u003csup\u003e11\u003c/sup\u003e. Nevertheless, the evaluation was conducted on the culture samples of MTB instead of clinical samples directly. Although it is featured with high throughput, speed, sensitivity, high accuracy and low cost, investigations on the application of nucleotide MALDI-TOF MS assay for PTB diagnosis in real world are still extremely limited and more research data are needed for support. To this end, we conducted this retrospective study to evaluate the diagnostic performance of nucleotide MALDI-TOF MS assay on BALFs from suspected PTB patients in Southwestern region of China with relatively large sample size. Li et al. and Yang et al. have published similar articles with very small sample size (37 and 52 BALFs respectively), likely resulting in big bias \u003csup\u003e19,20\u003c/sup\u003e. The results of various methods in their study were generally higher than those obtained from our study. The influential factors among them may be various other than the sample size, such as study site, the experimental operators.\u003c/p\u003e \u003cp\u003eBALF is the most common used respiratory sample type for the diagnosis of PTB besides sputum, which is also preferred by clinicians due to its closer proximity to the lesion. Multiple studies have reported the capability of different molecular tests to diagnose PTB in BALFs, such as Xpert MTB/RIF assay, SAT-TB, LAMP, next-generation metagenome sequencing, nanopore sequencing, etc., with sensitivities raging from 45.18\u0026ndash;94.4% \u003csup\u003e21\u0026ndash;26\u003c/sup\u003e. The comparatively lower results of the Xpert MTB/RIF assay in our study than those previously studies may be related to several factors, including study site, sample source, and the operator, suggesting that we need to improve the level of testing within our hospital. On the other hand, it is essential to emphasize the acquisition of high-quality specimens, since this often determines the final yield. Jiang et al., have demonstrated that attention to sputum quality can significantly increase bacteriological confirmation\u003csup\u003e27\u003c/sup\u003e. None the less, the very recent published study also showed a low sensitivity of Xpert MTB/RIF assay on BALFs to be 34.78%, lower than ours \u003csup\u003e28\u003c/sup\u003e. We can also assess the impact of BALF quality on bacteriological confirmation in the future.\u003c/p\u003e \u003cp\u003eIn our study, 14 cases were found to be nucleotide MALDI-TOF MS assay-negative but culture-positive. Finally, eight of them (57.1%) were clinically diagnosed with PTB and others were diagnosed with non-PTB. These false negatives may be due to insufficient nucleic acid or PCR inhibitors in BALFs\u003csup\u003e29\u003c/sup\u003e. On the other hand, 85 patients were found to be nucleotide MALDI-TOF MS assay-positive but culture-negative, 83 of which were diagnosed with PTB. This occurred might have several reasons. First, positive culture required live bacilli and the treatment history of patients might lead to negative cultures. Second, successful cultures require various factors including reagents, instruments, storage and expertise in operation\u003csup\u003e30\u003c/sup\u003e. In terms of the turnaround time of MGIT 960 culture and nucleotide MALDI-TOF MS assay, the detection time of results obtained from culture in our hospital ranged from 14 to 50 days where less than one day for nucleotide MALDI-TOF MS assay.\u003c/p\u003e \u003cp\u003eWe here also analyzed the consistency of nucleotide MALDI-TOF MS assay and Xpert MTB/RIF for rifampicin sensitivity with a good agreement between the two assays. Rifampicin susceptibility culture results using MGIT 960 system, were all available for the six discordant samples. We observed that all samples discordant with culture results were RIF-resistant using nucleotide MALDI-TOF MS assay. Several reasons might be responsible for this inconsistence. MGIT 960 drug susceptibility testing was prone to yield false sensitive results for samples with minimal inhibitory concentrations (MICs) for rifampicin close to cut-off value\u003csup\u003e31\u003c/sup\u003e. Heteroresistance should also be considered as a factor that might influence the outcomes since nucleotide MALDI-TOF MS assay has ability to detect low-level heterogeneous drug resistance with the limit of 0.1%\u003csup\u003e32\u003c/sup\u003e. Certainly, technical errors of nucleotide MALDI-TOF MS assay leading to false resistance cannot be ruled out, after all, the results of the other two methods were consistent.\u003c/p\u003e \u003cp\u003eOur study has several limitations. First, it was a retrospectively study conducted at a single center. We couldn\u0026rsquo;t control several factors appeared in this study, such as not all of samples were conducted using culture or Xpert MTB/RIF assay. In order to obtain much more precise evaluation of performance of nucleotide MALDI-TOF MS assay, prospective and multicenter studies should be designed in future. Second, smear microscopy and nucleotide MALDI-TOF MS assay were performed on all of the samples, whereas MGIT 960 culture and Xpert MTB/RIF were not always done, thus resulting in some biases because of the missing data. Third, bronchoscopy was invasive and not acceptable to all patients, which was performed after carefully considered to be necessary to obtain BALFs, such as a high suspicion of PTB. This resulted in the majority of enrolled patients diagnosed as PTB, with bias in terms of specificity. Finally, in terms of the inconsistent samples for rifampicin susceptibility identified with nucleotide MALDI-TOF MS and Xpert MTB/RIF, we didn\u0026rsquo;t perform sequencing to further validate.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, this study has shown nucleotide MALDI-TOF MS assay of BALFs is an accurate tool for the early diagnosis of PTB with high sensitivity and comparable specificity, which can provide more effective guidance for the treatment of PTB.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgments\u003c/p\u003e\n\u003cp\u003eThe authors acknowledged the staff at Chongqing Tuberculosis Control Institute, Chongqing Public Health Medical Center. This research was funded by Chongqing medical scientific research project, grant number 2023MSXM0321.\u003c/p\u003e\n\u003cp\u003eAuthor Contributions\u003c/p\u003e\n\u003cp\u003eConceptualization, Ling Jiang and Tongxin Li; Data curation, Tongxin Li; Formal analysis, Lijun Liang and Mingqiang Xia; Funding acquisition, Ling Jiang; Investigation, Mingqiang Xia and Jiyao Li; Methodology, Lijun Liang, Mingqiang Xia, Jiyao Li, Junqiu Xin, Jingfeng Tong and Chengchen Huang; Resources, Tongxin Li; Software, Jingfeng Tong and Chengchen Huang; Supervision, Tongxin Li; Validation, Ling Jiang and Tongxin Li; Writing \u0026ndash; original draft, Ling Jiang and Junqiu Xin; Writing \u0026ndash; review \u0026amp; editing, Tongxin Li. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors have no competing interests to declare.\u003c/p\u003e\n\u003cp\u003eData availability\u003c/p\u003e\n\u003cp\u003eAll the data and material were true and available. The data is available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003eEthics declarations\u003c/p\u003e\n\u003cp\u003eThe study protocol was approved by the Ethics Committee of Chongqing Public Health Medical Center of China (2023-013). The requirement of written informed consent was waived owing to the retrospective study design with approval from the Research Ethics Committee of the study hospital.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eWorld Health Organization. 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J. \u003cem\u003eet al.\u003c/em\u003e Ultrasensitive Detection of Multiplexed Somatic Mutations Using MALDI-TOF Mass Spectrometry. \u003cem\u003eJournal of Molecular Diagnostics\u003c/em\u003e \u003cstrong\u003e18\u003c/strong\u003e, 23\u0026ndash;31 (2016).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"bronchoalveolar lavage fluid, nucleotide MALDI-TOF MS, Xpert MTB/RIF, pulmonary tuberculosis, diagnosis","lastPublishedDoi":"10.21203/rs.3.rs-4014901/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4014901/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTo evaluate the diagnostic accuracy of matrix-assisted laser desorption ionization time-of-flight mass spectrometry based on nucleotide (nucleotide MALDI-TOF MS) on bronchoalveolar lavage fluid (BALF) from suspected pulmonary tuberculosis (PTB) patients. A retrospective study was conducted on suspected PTB patients admitted to Chongqing Public Health Medical Center between May 2021 and January 2022. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC) values of nucleotide MALDI-TOF MS as well as smear microscopy, Mycobacterium Growth Indicator Tube 960 culture (MGIT 960 culture), and Xpert MTB/RIF were calculated and compared. Total of 343 presumed PTB cases were enrolled. Overall, using the clinical diagnosis as reference, the sensitivity and NPV of nucleotide MALDI-TOF MSwas 71.5% and 43.1%, respectively, significantly higher than smear microscopy (22.6%, 23.2%), MGIT 960 culture (40.6%, 18.9%), Xpert MTB/RIF (40.8%, 27.9%). Furthermore, nucleotide MALDI-TOF MS also outperformed over Xpert MTB/RIF and MGIT 960 culture on smear-negative BALFs. Approximately 50% and 30% of patients benefited from nucleotide MALDI-TOF MS compared with smear and MGIT 960 culture or Xpert MTB/RIF, respectively. This study demonstrated that the analysis of BALF with nucleotide MALDI-TOF MS provided an accurate and promising tool for the early diagnosis of PTB.\u003c/p\u003e","manuscriptTitle":"Evaluation of nucleotide MALDI-TOF MS on bronchoalveolar lavage fluid for pulmonary Tuberculosis: experience from a tertiary hospital in southwestern China","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-03-21 18:34:25","doi":"10.21203/rs.3.rs-4014901/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-04-26T03:23:56+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-04-24T17:28:03+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-04-08T16:15:25+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-03-29T14:32:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"05a1e9f0-ae2b-44c3-972b-6d45475dc1f7","date":"2024-03-27T02:41:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"24bff2fa-0a2c-4b55-acd3-8c4b1c3caa0d","date":"2024-03-26T14:49:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"f386dab0-ff72-4d16-98c1-12c9f3bcd5e1","date":"2024-03-25T14:59:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"4d60ae33-889e-4137-8f78-1076f63e1f0e","date":"2024-03-24T08:49:16+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-03-24T04:54:28+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-03-24T04:44:11+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-03-18T18:25:06+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-03-18T18:10:06+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-03-05T02:31:22+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c3cf93a0-081f-4871-9794-23df202b6a01","owner":[],"postedDate":"March 21st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":29664334,"name":"Biological sciences/Microbiology"},{"id":29664335,"name":"Biological sciences/Microbiology/Clinical microbiology"}],"tags":[],"updatedAt":"2024-08-12T16:15:56+00:00","versionOfRecord":{"articleIdentity":"rs-4014901","link":"https://doi.org/10.1038/s41598-024-66178-8","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2024-08-08 15:58:09","publishedOnDateReadable":"August 8th, 2024"},"versionCreatedAt":"2024-03-21 18:34:25","video":"","vorDoi":"10.1038/s41598-024-66178-8","vorDoiUrl":"https://doi.org/10.1038/s41598-024-66178-8","workflowStages":[]},"version":"v1","identity":"rs-4014901","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4014901","identity":"rs-4014901","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}