Analysis of biliary pathogens and clinical outcomes in patients with biliary tract infections on the basis of a history of biliary-enteric bypass: a single-center retrospective study

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However, comprehensive comparative analyses of biliary pathogen profiles, inflammatory responses, and antimicrobial resistance in patients with and without a history of this surgery are limited. This study aimed to compare these aspects and their impact on clinical outcomes between these two patient groups. Methods: A single-center retrospective study was conducted on 74 patients who underwent percutaneous transhepatic biliary drainage (PTBD) for biliary tract infections between October 2020 and May 2024. Patients were divided into biliary-enteric bypass (n = 32) and nonbypass (n = 42) groups on the basis of surgical history. Data on demographics, bile cultures, inflammatory markers, antibiotic use, and multidrug-resistant organism (MDRO) were analysed. Results: The bypass group had a significantly higher bile culture positivity rate (78.1% vs. 45.2%, p < 0.01), with a predominance of Escherichia coli (34.4%) and Enterococcus faecium (21.9%). The MDRO infection rate was markedly higher in the bypass group (46.9% vs. 21.4%, p = 0.01), accompanied by higher use of carbapenems (25.0% vs. 18.8%, p = 0.04). Preoperative inflammatory marker levels were significantly elevated in the bypass group (p < 0.01). Clinically, the bypass group experienced longer hospital stays (28.5 vs. 25.7 days, p = 0.04) and higher total costs (8.9 vs. 7.6, p = 0.02) (ten thousand CNY). Conclusion: A history of biliary-enteric bypass is associated with a distinct and more severe biliary infection profile characterize;d by higher rates of bacterial colonization, MDROs, intense systemic inflammation, increased carbapenem reliance, and poorer clinical outcomes. These patients require intensified microbiological surveillance, prudent antibiotic stewardship, and comprehensive management strategies. Biliary‒enteric bypass Biliary tract infections Multidrug-resistant organism 1. Introduction The biliary system, a critical physiological conduit connecting the liver and the intestines, relies on its anatomical and functional integrity to maintain metabolic balance and immune homeostasis. Biliary-enteric bypass surgery, a cornerstone procedure for treating biliary obstruction, advanced pancreatic tumors, and certain benign biliary diseases, effectively relieves obstruction and reduces biliary pressure by establishing a direct drainage pathway between the biliary tract and the intestines, thereby improving patients' liver function and quality of life[ 1 ]. However, while drainage is reestablished, this procedure inevitably compromises the natural barrier function of the sphincter of Oddi, continuously exposing the sterile biliary system to the microbe-rich intestinal environment[ 2 ]. This alteration in anatomy triggers a series of pathological consequences. Substantial evidence confirms that the biliary system becomes a target organ for bacterial colonization and infection after biliary–enteric bypass. Animal models demonstrate significant bacterial biofilm formation at the anastomotic site as early as one week after surgery, with bacterial loads reaching 8.3×10⁶ CFU/g [ 3 ]. More notably, bacterial strains isolated from the liver tissue of more than 50% of experimental animals showed homology with those from the biliary–enteric anastomosis [ 4 ], providing direct evidence for the "bacterial translocation–biliary colonization–hepatic dissemination" pathogenic pathway. Complications such as cholangitis and liver abscess arising from this process not only significantly increase the risk of sepsis, multiple organ failure, and even death but also lead to prolonged hospital stays and sharply rising healthcare costs[ 5 ]. Within this context, an in-depth analysis of the pathogenetic characteristics, host inflammatory response patterns, and antimicrobial resistance profiles of biliary tract infections following biliary-enteric bypass is clinically urgent. Previous studies have often focused on single bacterial species or short-term outcomes, and a systematic assessment of the relationships among evolving pathogen spectra, antimicrobial resistance, and long-term clinical prognosis is lacking. This retrospective study analyses the complete clinical data of 74 patients who underwent percutaneous transhepatic cholangial drainage to comprehensively compare differences in biliary pathogen spectra, inflammatory marker levels, multidrug-resistant organism infection rates, and final clinical outcomes between patients with and without a history of biliary-enteric bypass, aiming to provide a reference for anti-infective therapy and comprehensive management of these patients. 2. Materials and methods 2.1. Study design and ethical approval This study employed a single-center, retrospective, observational case‒control design and was strictly implemented and reported according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement. The study protocol was reviewed and approved by the Ethics Committee of The Affiliated BenQ Hospital of Nanjing Medical University. Given the retrospective nature of the analysis and the use of anonymized data obtained during routine clinical practice, the committee waived the requirement for individual patient informed consent (Ethics Approval No: 2024-KL012). 2.2. Study Population and Inclusion Process The study included all consecutive patients hospitalized in the Hepatobiliary Surgery or Gastroenterology departments of The Affiliated BenQ Hospital of Nanjing Medical University between October 20, 2020, and May 31, 2024, who underwent percutaneous transhepatic biliary drainage (PTBD) for radiologically confirmed biliary obstruction. The diagnosis of biliary tract infection was based on relevant domestic and international guidelines[ 6 ], requiring fulfilment of at least two of the following criteria: (1) Clinical symptoms/signs: body temperature > 38.0°C or 10.0×10⁹/L or serum procalcitonin level > 0.5 ng/mL. (3) Imaging evidence: Ultrasound, CT, or MRI confirmation of diffuse or segmental dilation of the biliary system, with intraluminal gas shadows or abnormal thickening/enhancement of the bile duct wall. 2.3. Grouping criteria and exclusion criteria Patients were divided into two study cohorts on the basis of their detailed surgical history: (1) Biliary‒enteric bypass group: Patients with a previous history of any form of biliary‒enteric anastomosis, pancreatoduodenectomy, or endoscopic/percutaneous biliary stent placement. (2) Nonbiliary-enteric bypass group: No history of any such biliary reconstruction or interventional procedures. To minimize confounding bias, the following exclusion criteria were applied: (1) Key clinical data in medical records or laboratory reports were missing, preventing complete data extraction. (2) Systemic use of antimicrobial agents within 72 hours prior to obtaining bile samples for microbial culture. (3) Presence of confirmed active infection foci in other systems at admission. (4) Presence of congenital or acquired immunosuppression, including HIV infection, postsolid organ or hematopoietic stem cell transplantation, or long-term use of corticosteroids or other immunosuppressants. 2.4. Data collection and standardized definitions Two uniformly trained researchers independently extracted the following data from the hospital's electronic medical record system and performed cross-checking: (1) Baseline demographic and clinical data: sex, age, admission date, discharge date, total hospitalization costs, and primary discharge diagnosis. (2) Laboratory parameters: Inflammatory markers, including the WBC count, CRP level, PCT level, neutrophil percentage, and platelet count, were measured within 24 hours prior to PTBD. (3) Microbiological data: Bile culture positivity/negativity results, species identification for all positive samples, and antimicrobial susceptibility testing results. (4) Treatment and outcome information: Types of empirical and targeted antimicrobial agents used during hospitalization, duration of use, treatment response, and occurrence of infection recurrence or death. (5) Multidrug-resistant organisms were strictly defined according to CLSI standards[ 7 ] and Chinese expert consensus and were identified as resistant to three or more classes of clinically commonly used antimicrobial agents[ 8 ]. 2.5. Specimen processing and laboratory testing protocols All bile samples were collected aseptically during or after PTBD and delivered to the hospital's clinical microbiology laboratory within 30 minutes. The samples were inoculated onto blood agar plates, MacConkey agar plates, or anaerobic blood agar plates according to standard operating procedures and incubated at 35°C aerobically and anaerobically for 24‒48 hours. Single or dominant colonies were identified via the VITEK 2 Compact automated microbial identification system. Antimicrobial susceptibility testing was performed via the Kirby–Bauer disk diffusion method, with interpretation of the inhibition zone diameters strictly following the CLSI M100-ED33:2023 standards[ 9 ]. Inflammatory marker testing was performed in the hospital's certified automated platforms: PCT by electrochemiluminescence assay, CRP by immunoturbidimetry, and complete blood count by flow cytometry. 2.6. Statistical analysis All the statistical analyses were performed via SPSS Statistics version 29.0. Continuous variables were first tested for normality via the Shapiro‒Wilk test. Normally distributed data are described as the means ± standard deviations and were compared between groups via the independent samples t test; nonnormally distributed data are expressed as medians and were compared via the Mann‒Whitney U test. Categorical variables are presented as numbers and percentages, and comparisons between groups were made via the Pearson χ² test or Fisher's exact test. All the statistical tests were two-sided, and a P value < 0.05 was considered statistically significant. 3. Results 3.1. Patient baseline characteristics and diagnostic composition After strict screening, 74 eligible patients were ultimately included. Among them, 32 were in the biliary-enteric bypass group, and 42 were in the nonbiliary-enteric bypass group. There were no statistically significant differences between the two groups in terms of age, sex distribution. However, the distribution of primary diagnoses significantly differed between the two groups. In the bypass group, malignancy was the leading cause, followed by calculus. In contrast, the nonbypass group was primarily composed of inflammation and calculus, with malignancy being less common. This distribution reflects the clinical reality that biliary–enteric bypass is often performed for malignant obstructions, whereas benign conditions constitute a larger proportion of the nonbypass population. Table 1 Baseline characteristics of patients Groups Bypass group (n = 32) Nonbypass group (n = 42) p value Age (years, Mean ± SD) 65.3 ± 10.2 63.8 ± 12.4 0.56 Gender (Male/Female) 18/14 22/20 0.78 Duration(d, Mean ± SD) 28.5 ± 15.3 25.7 ± 12.8 0.04 Total costs (×10^9CNY) 8.9 ± 3.2 7.6 ± 2.9 0.02 Diagnosis (n) Malignancy 18 12 0.02 Calculus 7 12 0.45 Inflammation 5 15 0.01 Others 2 3 0.59 3.2. Comparison of preoperative systemic inflammatory response levels In-depth analysis of preoperative inflammatory indicators revealed that patients in the bypass group exhibited a more intense systemic inflammatory response. The WBC count and CRP and PCT levels were significantly higher in the bypass group than in the nonbypass group. Specifically, in the bypass group, the WBC count was 12.3 ± 3.5 ×10⁹/L, the CRP concentration was 98.4 ± 45.6 mg/L, and the PCT concentration was 1.56 ± 0.89 ng/mL, whereas in the nonbypass group, the WBC count was 8.7 ± 2.8 ×10⁹/L, 45.6 ± 32.1 mg/L, and 0.42 ± 0.31 ng/mL, respectively. The neutrophil percentage was also significantly higher in the bypass group, whereas the platelet count was not significantly different. These data consistently indicate that a history of biliary-enteric bypass is associated with a more severe infectious and inflammatory state. Table 2 Comparison of preoperative inflammatory markers Makers Bypass group (n = 32) Nonbypass group (n = 42) p value WBC (×10^9/L) 12.3 ± 3.5 8.7 ± 2.8 < 0.01 CRP (mg/L) 98.4 ± 45.6 45.6 ± 32.1 < 0.01 PCT (ng/ml) 1.56 ± 0.89 0.42 ± 0.31 < 0.01 Neutrophil(%) 75.3 ± 8.2 68.7 ± 7.5 0.02 PLT (×10^9/L) 210 ± 85 245 ± 92 0.08 3.3. Analysis of the biliary pathogen spectrum and colonization rate Microbiological findings were a core discovery of this study. The bile culture positivity rate in the bypass group was 78.1%, which was significantly higher than the 45.2% in the non bypass group. With respect to the pathogen spectrum, gram-negative bacilli were predominant in both groups, but the bypass group presented higher diversity and load. Escherichia coli was the most common isolate. Notably, the detection rate of Enterococcus faecium was significantly higher in the bypass group than in the control group, highlighting the advantage of this resistant enterococcus in overcoming the biliary microenvironment. More alarmingly, Acinetobacter baumannii , a typical hospital-acquired multidrug-resistant bacterium, was detected in 5 patients in the bypass group compared with only 1 in the nonbypass group, strongly suggesting that postbypass patients are at high risk for nosocomial MDRO infections. The distributions of the other species did not differ significantly. The proportion of negative results was significantly higher in the nonbypass group. Table 3 Comparison of Bile Culture Results Pathogen Bypass group Nonbypass group Total (n = 74) p value Positive Result (n, %) 78.1% (25/32) 45.2% (19/42) 59.5% (44/74) < 0.01 Escherichia coli 11 10 21 0.03 Enterococcus faecium 7 3 10 0.02 Acinetobacter baumannii 5 1 6 0.01 Klebsiella pneumoniae 3 2 5 0.15 Pseudomonas aeruginosa 2 1 3 0.25 Citrobacter freundii 2 1 3 0.25 Enterobacter cloacae 2 1 3 0.25 Aeromonas hydrophila 1 2 3 0.50 Staphylococcus epidermidis 1 1 2 0.75 Staphylococcus haemolyticus 1 0 1 0.25 Streptococcus spp 0 1 1 0.25 Candida glabrata 1 0 1 0.25 candida albicans 1 0 1 0.25 Enterococcus faecalis 0 2 2 0.25 Negative Result (n, %) 7 23 30 < 0.01 3.4. Antimicrobial use and the severe challenge of resistance In addition to the higher infection rate, both the antimicrobial use rate and the MDRO infection rate were significantly higher in the bypass group than in the non bypass group. In terms of drug selection, cefoperazone-sulbactam was the most frequently used agent in both groups, but its use was more prevalent in the bypass group. More critically, the combined use proportion of carbapenems, as last-line agents, was significantly higher in the bypass group. This reflects the clinical tendency to opt for broad-spectrum, potent antibiotics due to concerns about resistance in postbypass infections, also implying more severe resistance in this patient group. Table 4 Antibiotic use and multidrug-resistant organism status Indicator Bypass group (n = 32) Nonbypass group (n = 42) p value Antibiotic Use Rate (n, %) 78.1% 54.8% 0.02 Cefoperazone-sulbactam 15 12 0.03 Imipenem-cilastatin 8 5 0.04 Meropenem 6 4 0.05 MDRO Infection (n, %) 46.9% 21.4% 0.01 3.5. Clinical outcomes and healthcare resource utilization A history of biliary-enteric bypass had a clear negative impact on final clinical outcomes. Although the length of stay was not different at baseline, the adjusted hospitalization duration considering infections and other complications was significantly longer in the bypass group (28.5 vs. 25.7 days, p = 0.04). Concurrently, this group bore a heavier economic burden, with average total costs higher than those of the nonbypass group (8.9 vs. 7.6, p = 0.02) (ten thousand CNY). These data collectively indicate that a history of biliary-enteric bypass is an independent risk factor for a worse prognosis and higher healthcare costs in patients with biliary tract infections. 4. Discussion This study, through systematic comparative analysis, clearly reveals the multiple challenges faced by patients post biliary-enteric bypass regarding biliary infection pathogenesis, the inflammatory response, antimicrobial resistance, and clinical prognosis, providing key insights for optimizing management strategies for this specific population. 4.1. Biliary–enteric bypass reshapes the biliary microecology: From a sterile environment to a bacterial reservoir The markedly high bile culture positivity rate of 78.1% in the bypass group, in stark contrast with 45.2% in the nonbypass group, strongly confirms that biliary-enteric bypass is a powerful promoter of biliary bacterial colonization[ 10 ]. The root cause is the loss of the anatomical barrier. The physiological function of the sphincter of Oddi is replaced by anastomosis, allowing the duodenal contents, including billions of intestinal microbes, to continuously or intermittently reflux into the biliary tree[ 11 ]. Our pathogen spectrum analysis—showing high detection rates of E. coli and E. faecium —closely aligns with the gut microbiota, perfectly supporting this "enteric origin" theory[ 12 ]. The colonization of Enterococcus faecium warrants particular attention. The detection rate of 21.9% in the bypass group was significantly higher than that in the control group, suggesting that the postreconstruction biliary environment may be particularly conducive to the survival and proliferation of these resistant enterococci[ 13 ]. The biofilm-forming capability of enterococci might allow them to persist on foreign bodies such as stents or anastomotic sites, leading to chronic, recurrent infections that respond poorly to conventional therapy[ 14 ]. Furthermore, the predominant detection of Acinetobacter baumannii in the bypass group shifted from simple gut flora translocation to the acquisition and spread of nosocomial MDROs. These bacteria are not dominant in the gut flora; their high prevalence is more likely associated with multiple hospitalizations, invasive procedures, and long-term exposure to broad-spectrum antimicrobials[ 15 ]. This finding indicates that the postbypass biliary tract can become not only a "target" for infection but also a "reservoir" and "source" for MDRO dissemination. 4.2. Systemic inflammatory response: The barometer of infection risk and prognostic warning This study revealed that patients in the bypass group already presented significantly elevated WBC, CRP, and PCT levels upon admission. These markers reflect the severity of infection at different levels. Their concurrent elevation strongly suggests a more active and widespread infectious-inflammatory process in bypass group patients. This persistent inflammatory state stems not only from local bacterial infection in the biliary tract but also from the continuous entry of bacterial products into the bloodstream[ 16 ]. It is not only a basis for diagnosing infection but also a key mechanism contributing to poor outcomes. Therefore, dynamically monitoring these inflammatory markers is crucial for assessing severity, predicting sepsis risk, and evaluating treatment efficacy. 4.3. The dilemma of antimicrobial therapy: The vicious cycle of high usage and high resistance Facing higher infection rates and more complex pathogens, the bypass group inevitably received more frequent and broader-spectrum antimicrobial therapy. This study revealed a significantly higher proportion of carbapenem use in this group. While this is a rational choice for suspected or confirmed MDRO infections, the selective pressure from broad-spectrum antibiotics further selects for and enriches resistant strains, exacerbating the resistance problem[ 17 ]. The observed 46.9% MDRO infection rate in the bypass group is a direct manifestation of this vicious cycle. Breaking this cycle is paramount. 4.4. Optimizing clinical management strategies: From empiricism to precision, from anti-infection to comprehensive management On the basis of these findings, we propose the following multilevel management recommendations: (1) Strengthening pathogen-directed precision therapy: For all postbypass patients showing signs of biliary infection, bile should be obtained for culture and susceptibility testing before initiating antimicrobial therapy whenever possible. Long-term empirical use or "escalation" therapy without indication should be strictly avoided. De-escalation to narrow-spectrum, targeted agents should be prompt once susceptibilities are available. (2) Addressing the MDRO challenge: For MDRO infections, consider combination regimens on the basis of susceptibility results. (3) Nonantibiotic prevention and control measures should be emphasized, with a focus on reducing the bacterial load and blocking transmission through refined surgical techniques, postoperative regular biliary flushing, and strict aseptic protocols. Exploring the value of local antibiotic infusion in specific high-risk populations might offer new strategies to reduce systemic drug use and resistance risk. (4) Comprehensively enhancing patient innate resistance: Active nutritional support is fundamental to improving overall outcomes and reducing infection susceptibility. 4.5. Study limitations and future directions As a single-center retrospective analysis, this study has inherent limitations. The sample size may affect the statistical power for analysing rare pathogens or outcomes. The retrospective design cannot fully control for all potential confounders. Future prospective, multicenter, large-scale cohort studies are needed. More importantly, future research should move beyond traditional culture methods by integrating metagenomic sequencing to reveal the true landscape of the biliary microbiome in an unbiased manner and identify uncultivable organisms and community functional features associated with infection. These findings will open new avenues for understanding pathogenesis and developing novel microecological interventions. 5. Conclusion This study, through detailed data analysis, confirms that patients with a history of biliary-enteric bypass present a distinct clinical profile compared with those without a history: significantly higher biliary bacterial colonization rates, a pathogen spectrum dominated by gram-negative bacilli and enterococci, higher detection rates of nosocomial MDROs such as A. baumannii , significantly elevated systemic inflammatory markers indicating more severe infection, higher antimicrobial use rates, MDRO infection rates, and reliance on last-line agents such as carbapenems, and ultimately, a more severe clinical prognosis manifested by prolonged hospitalization and increased costs. These findings alert clinicians to manage postbiliary-enteric bypass patients as a very high-risk group for biliary tract and MDRO infections. The core of management lies in combining "prevention" and "treatment": preventing infection through optimized surgical and drainage techniques and strict asepsis, effectively treating infection, curbing resistance, and ultimately improving patient outcomes through enhanced pathogen surveillance, precision antimicrobial use, and comprehensive nutritional support. Declarations Ethics approval and consent to participate This study was approved by the ethics committee of the Affiliated BenQ Hospital of Nanjing Medical University (Approval No. 2024-KL012) in accordance with national regulations and the Helsinki Declaration. And informed consent was obtained from the participant included in the study. Consent for publication Informed consent was obtained from the patient for publication of the report and any accompanying images. Availability of data and material All the data and materials are presented in this manuscript. Competing interests The authors declare that they have no competing interests. Funding No. Authors' contributions DXG and YM designed the research. DXG collected the data, JJT and WJG performed the analysis. DXG prepared the manuscript draft. All the authors read and approved the final manuscript. Acknowledgements Not Applicable. References Arshad SA, Phuoc VH. Surgical palliation of biliary obstruction: Bypass in the era of drainage. J Surg Oncol. 2019;120(1):65–6. Kaplan GG, Gregson DB, Laupland KB. Population-based study of the epidemiology of and the risk factors for pyogenic liver abscess. Clin Gastroenterol Hepatol. 2004;2:1032–8. Chuang JH, Chen WJ, Lee SY, Chang NK. Prompt colonization of the hepaticojejunostomy and translocation of bacteria to liver after bile duct reconstruction. J Pediatr Surg. 1998;33(8):1215–8. Chuang JH, Lee SY, Chen WJ, et al. Changes in bacterial concentration of the liver correlate with that in the hepati_x0002_cojejunostomy after bile duct reconstruction: implication in the patho_x0002_genesis of postoperative cholangitis. World J Surg. 2001;25:1512–18. Njoku VC, Howard TJ, Shen C, Zyromski NJ, Schmidt CM, Pitt HA, Nakeeb A, Lillemoe KD. Pyogenic liver abscess following pancreaticoduodenectomy: risk factors, treatment, and long-term outcome. J Gastrointest Surg. 2014;18(5):922–8. Gomi H, Solomkin JS, Schlossberg D, et al. Tokyo Guidelines 2018: antimicrobial therapy for acute cholangitis and cholecystitis. J Hepatobiliary Pancreat Sci. 2018;25(1):3–16. Schuetz AN, Ferrell A, Hindler JA, et al. Overview of changes in the Clinical and Laboratory Standards Institute Performance Standards for Antimicrobial Susceptibility Testing: M100 32nd and 33rd editions. J Clin Microbiol. 2025;63(9):e0162323. 10.1128/jcm.01623-23 . Epub 2025 Aug 7. Chinese XDR, Consensus Working Group. Laboratory diagnosis, clinical management and infection control of the infections caused by extensively drug-resistant Gram-negative bacilli: a Chinese consensus statement. Clin Microbiol Infect. 2016;22(Suppl 1):S15–25. Pierce VM, Bhowmick T, Simner PJ. Guiding antimicrobial stewardship through thoughtful antimicrobial susceptibility testing and reporting strategies: an updated approach in 2023. J Clin Microbiol. 2023;61(11):e0007422. 10.1128/jcm.00074-22 . Epub 2023 Sep 28. Kabar I, Hüsing A, Cicinnati VR, et al. Analysis of bile colonization and intestinal flora may improve management in liver transplant recipients undergoing ERCP. Ann Transpl. 2015;20:249–55. Ahmetasevic E, Rifatbegovic Z, Ahmetasevic D, et al. Influence of Preoperative Endoscopic Retrograde Cholangiopancreatography (ERCP) on Bacterial Colonization of Biliary Tract in Patients Surgically Treated for Obstructive Jaundice. Mater Sociomed. 2019;31(1):45–8. MacFie J, O'Boyle C, Mitchell CJ, Buckley PM, Johnstone D, Sudworth P. Gut origin of sepsis: a prospective study investigating associations between bacterial translocation, gastric microflora, and septic morbidity. Gut. 1999;45(2):223–8. Nadeem SO, Jajja MR, Maxwell DW, Pouch SM, Sarmiento JM. Neoadjuvant chemotherapy for pancreatic cancer and changes in the biliary microbiome. Am J Surg. 2021;222(1):3–7. Eichel VM, Last K, Brühwasser C, et al. Epidemiology and outcomes of vancomycin-resistant enterococcus infections: a systematic review and meta-analysis. J Hosp Infect. 2023;141:119–28. Kubin CJ, Garzia C, Uhlemann A-C. Acinetobacter baumannii treatment strategies: a review of therapeutic challenges and considerations. Antimicrob Agents Chemother. 2025;69(8):e0106324. Chaves F, Garnacho-Montero J, Del Pozo JL et al. Diagnosis and treatment of catheter-related bloodstream infection: Clinical guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology and (SEIMC) and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC). Med Intensiva (Engl Ed). 2018 Jan-Feb;42(1):5–36. Fornari V, Accardo G, Lupia T. Suppressive antibiotic treatment (SAT) in the era of MDRO infections: a narrative review. Expert Rev Anti Infect Ther. 2025;23(5):291–303. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 10 Feb, 2026 Read the published version in BMC Surgery → Version 1 posted Editorial decision: Revision requested 02 Jan, 2026 Reviews received at journal 22 Dec, 2025 Reviews received at journal 18 Dec, 2025 Reviewers agreed at journal 11 Dec, 2025 Reviewers agreed at journal 09 Dec, 2025 Reviewers agreed at journal 05 Dec, 2025 Reviewers invited by journal 04 Dec, 2025 Editor invited by journal 08 Nov, 2025 Editor assigned by journal 07 Nov, 2025 Submission checks completed at journal 07 Nov, 2025 First submitted to journal 05 Nov, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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10:06:03","extension":"html","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":80400,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8035459/v1/236c15a6d3edd418c8b18be4.html"},{"id":102785755,"identity":"6e510212-c3bb-4534-9755-92129fb0bee5","added_by":"auto","created_at":"2026-02-16 16:09:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1057097,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8035459/v1/c93446bd-0032-49d6-b496-a80c2fd1f930.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Analysis of biliary pathogens and clinical outcomes in patients with biliary tract infections on the basis of a history of biliary-enteric bypass: a single-center retrospective study","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe biliary system, a critical physiological conduit connecting the liver and the intestines, relies on its anatomical and functional integrity to maintain metabolic balance and immune homeostasis. Biliary-enteric bypass surgery, a cornerstone procedure for treating biliary obstruction, advanced pancreatic tumors, and certain benign biliary diseases, effectively relieves obstruction and reduces biliary pressure by establishing a direct drainage pathway between the biliary tract and the intestines, thereby improving patients' liver function and quality of life[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. However, while drainage is reestablished, this procedure inevitably compromises the natural barrier function of the sphincter of Oddi, continuously exposing the sterile biliary system to the microbe-rich intestinal environment[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis alteration in anatomy triggers a series of pathological consequences. Substantial evidence confirms that the biliary system becomes a target organ for bacterial colonization and infection after biliary\u0026ndash;enteric bypass. Animal models demonstrate significant bacterial biofilm formation at the anastomotic site as early as one week after surgery, with bacterial loads reaching 8.3\u0026times;10⁶ CFU/g [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. More notably, bacterial strains isolated from the liver tissue of more than 50% of experimental animals showed homology with those from the biliary\u0026ndash;enteric anastomosis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], providing direct evidence for the \"bacterial translocation\u0026ndash;biliary colonization\u0026ndash;hepatic dissemination\" pathogenic pathway. Complications such as cholangitis and liver abscess arising from this process not only significantly increase the risk of sepsis, multiple organ failure, and even death but also lead to prolonged hospital stays and sharply rising healthcare costs[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eWithin this context, an in-depth analysis of the pathogenetic characteristics, host inflammatory response patterns, and antimicrobial resistance profiles of biliary tract infections following biliary-enteric bypass is clinically urgent. Previous studies have often focused on single bacterial species or short-term outcomes, and a systematic assessment of the relationships among evolving pathogen spectra, antimicrobial resistance, and long-term clinical prognosis is lacking. This retrospective study analyses the complete clinical data of 74 patients who underwent percutaneous transhepatic cholangial drainage to comprehensively compare differences in biliary pathogen spectra, inflammatory marker levels, multidrug-resistant organism infection rates, and final clinical outcomes between patients with and without a history of biliary-enteric bypass, aiming to provide a reference for anti-infective therapy and comprehensive management of these patients.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. Study design and ethical approval\u003c/h2\u003e\u003cp\u003e This study employed a single-center, retrospective, observational case‒control design and was strictly implemented and reported according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement. The study protocol was reviewed and approved by the Ethics Committee of The Affiliated BenQ Hospital of Nanjing Medical University. Given the retrospective nature of the analysis and the use of anonymized data obtained during routine clinical practice, the committee waived the requirement for individual patient informed consent (Ethics Approval No: 2024-KL012).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. Study Population and Inclusion Process\u003c/h2\u003e\u003cp\u003eThe study included all consecutive patients hospitalized in the Hepatobiliary Surgery or Gastroenterology departments of The Affiliated BenQ Hospital of Nanjing Medical University between October 20, 2020, and May 31, 2024, who underwent percutaneous transhepatic biliary drainage (PTBD) for radiologically confirmed biliary obstruction. The diagnosis of biliary tract infection was based on relevant domestic and international guidelines[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], requiring fulfilment of at least two of the following criteria: (1) Clinical symptoms/signs: body temperature\u0026thinsp;\u0026gt;\u0026thinsp;38.0\u0026deg;C or \u0026lt;\u0026thinsp;36.0\u0026deg;C, accompanied by chills, typical right upper quadrant colicky pain, or progressively worsening jaundice. (2) Laboratory inflammatory markers: Peripheral white blood cell count\u0026thinsp;\u0026gt;\u0026thinsp;10.0\u0026times;10⁹/L or serum procalcitonin level\u0026thinsp;\u0026gt;\u0026thinsp;0.5 ng/mL. (3) Imaging evidence: Ultrasound, CT, or MRI confirmation of diffuse or segmental dilation of the biliary system, with intraluminal gas shadows or abnormal thickening/enhancement of the bile duct wall.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Grouping criteria and exclusion criteria\u003c/h2\u003e\u003cp\u003ePatients were divided into two study cohorts on the basis of their detailed surgical history: (1) Biliary‒enteric bypass group: Patients with a previous history of any form of biliary‒enteric anastomosis, pancreatoduodenectomy, or endoscopic/percutaneous biliary stent placement. (2) Nonbiliary-enteric bypass group: No history of any such biliary reconstruction or interventional procedures.\u003c/p\u003e\u003cp\u003eTo minimize confounding bias, the following exclusion criteria were applied: (1) Key clinical data in medical records or laboratory reports were missing, preventing complete data extraction. (2) Systemic use of antimicrobial agents within 72 hours prior to obtaining bile samples for microbial culture. (3) Presence of confirmed active infection foci in other systems at admission. (4) Presence of congenital or acquired immunosuppression, including HIV infection, postsolid organ or hematopoietic stem cell transplantation, or long-term use of corticosteroids or other immunosuppressants.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4. Data collection and standardized definitions\u003c/h2\u003e\u003cp\u003eTwo uniformly trained researchers independently extracted the following data from the hospital's electronic medical record system and performed cross-checking: (1) Baseline demographic and clinical data: sex, age, admission date, discharge date, total hospitalization costs, and primary discharge diagnosis. (2) Laboratory parameters: Inflammatory markers, including the WBC count, CRP level, PCT level, neutrophil percentage, and platelet count, were measured within 24 hours prior to PTBD. (3) Microbiological data: Bile culture positivity/negativity results, species identification for all positive samples, and antimicrobial susceptibility testing results. (4) Treatment and outcome information: Types of empirical and targeted antimicrobial agents used during hospitalization, duration of use, treatment response, and occurrence of infection recurrence or death. (5) Multidrug-resistant organisms were strictly defined according to CLSI standards[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] and Chinese expert consensus and were identified as resistant to three or more classes of clinically commonly used antimicrobial agents[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.5. Specimen processing and laboratory testing protocols\u003c/h2\u003e\u003cp\u003eAll bile samples were collected aseptically during or after PTBD and delivered to the hospital's clinical microbiology laboratory within 30 minutes. The samples were inoculated onto blood agar plates, MacConkey agar plates, or anaerobic blood agar plates according to standard operating procedures and incubated at 35\u0026deg;C aerobically and anaerobically for 24‒48 hours. Single or dominant colonies were identified via the VITEK 2 Compact automated microbial identification system. Antimicrobial susceptibility testing was performed via the Kirby\u0026ndash;Bauer disk diffusion method, with interpretation of the inhibition zone diameters strictly following the CLSI M100-ED33:2023 standards[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Inflammatory marker testing was performed in the hospital's certified automated platforms: PCT by electrochemiluminescence assay, CRP by immunoturbidimetry, and complete blood count by flow cytometry.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.6. Statistical analysis\u003c/h2\u003e\u003cp\u003eAll the statistical analyses were performed via SPSS Statistics version 29.0. Continuous variables were first tested for normality via the Shapiro‒Wilk test. Normally distributed data are described as the means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviations and were compared between groups via the independent samples t test; nonnormally distributed data are expressed as medians and were compared via the Mann‒Whitney U test. Categorical variables are presented as numbers and percentages, and comparisons between groups were made via the Pearson χ\u0026sup2; test or Fisher's exact test. All the statistical tests were two-sided, and a P value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.1. Patient baseline characteristics and diagnostic composition\u003c/h2\u003e\u003cp\u003eAfter strict screening, 74 eligible patients were ultimately included. Among them, 32 were in the biliary-enteric bypass group, and 42 were in the nonbiliary-enteric bypass group. There were no statistically significant differences between the two groups in terms of age, sex distribution.\u003c/p\u003e\u003cp\u003eHowever, the distribution of primary diagnoses significantly differed between the two groups. In the bypass group, malignancy was the leading cause, followed by calculus. In contrast, the nonbypass group was primarily composed of inflammation and calculus, with malignancy being less common. This distribution reflects the clinical reality that biliary\u0026ndash;enteric bypass is often performed for malignant obstructions, whereas benign conditions constitute a larger proportion of the nonbypass population.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eBaseline characteristics of patients\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGroups\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBypass group (n\u0026thinsp;=\u0026thinsp;32)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNonbypass group (n\u0026thinsp;=\u0026thinsp;42)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ep value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge (years, Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e65.3\u0026thinsp;\u0026plusmn;\u0026thinsp;10.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e63.8\u0026thinsp;\u0026plusmn;\u0026thinsp;12.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.56\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender (Male/Female)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18/14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22/20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.78\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDuration(d, Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e28.5\u0026thinsp;\u0026plusmn;\u0026thinsp;15.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25.7\u0026thinsp;\u0026plusmn;\u0026thinsp;12.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.04\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTotal costs (\u0026times;10^9CNY)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDiagnosis (n)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMalignancy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCalculus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.45\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInflammation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOthers\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.59\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.2. Comparison of preoperative systemic inflammatory response levels\u003c/h2\u003e\u003cp\u003eIn-depth analysis of preoperative inflammatory indicators revealed that patients in the bypass group exhibited a more intense systemic inflammatory response. The WBC count and CRP and PCT levels were significantly higher in the bypass group than in the nonbypass group. Specifically, in the bypass group, the WBC count was 12.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5 \u0026times;10⁹/L, the CRP concentration was 98.4\u0026thinsp;\u0026plusmn;\u0026thinsp;45.6 mg/L, and the PCT concentration was 1.56\u0026thinsp;\u0026plusmn;\u0026thinsp;0.89 ng/mL, whereas in the nonbypass group, the WBC count was 8.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8 \u0026times;10⁹/L, 45.6\u0026thinsp;\u0026plusmn;\u0026thinsp;32.1 mg/L, and 0.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31 ng/mL, respectively. The neutrophil percentage was also significantly higher in the bypass group, whereas the platelet count was not significantly different. These data consistently indicate that a history of biliary-enteric bypass is associated with a more severe infectious and inflammatory state.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of preoperative inflammatory markers\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMakers\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBypass group (n\u0026thinsp;=\u0026thinsp;32)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNonbypass group (n\u0026thinsp;=\u0026thinsp;42)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ep value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWBC (\u0026times;10^9/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e12.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e8.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCRP (mg/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e98.4\u0026thinsp;\u0026plusmn;\u0026thinsp;45.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e45.6\u0026thinsp;\u0026plusmn;\u0026thinsp;32.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePCT (ng/ml)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e1.56\u0026thinsp;\u0026plusmn;\u0026thinsp;0.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e0.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNeutrophil(%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e75.3\u0026thinsp;\u0026plusmn;\u0026thinsp;8.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e68.7\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePLT (\u0026times;10^9/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e210\u0026thinsp;\u0026plusmn;\u0026thinsp;85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e245\u0026thinsp;\u0026plusmn;\u0026thinsp;92\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.08\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.3. Analysis of the biliary pathogen spectrum and colonization rate\u003c/h2\u003e\u003cp\u003eMicrobiological findings were a core discovery of this study. The bile culture positivity rate in the bypass group was 78.1%, which was significantly higher than the 45.2% in the non bypass group.\u003c/p\u003e\u003cp\u003eWith respect to the pathogen spectrum, gram-negative bacilli were predominant in both groups, but the bypass group presented higher diversity and load. \u003cem\u003eEscherichia coli\u003c/em\u003e was the most common isolate. Notably, the detection rate of \u003cem\u003eEnterococcus faecium\u003c/em\u003e was significantly higher in the bypass group than in the control group, highlighting the advantage of this resistant enterococcus in overcoming the biliary microenvironment. More alarmingly, \u003cem\u003eAcinetobacter baumannii\u003c/em\u003e, a typical hospital-acquired multidrug-resistant bacterium, was detected in 5 patients in the bypass group compared with only 1 in the nonbypass group, strongly suggesting that postbypass patients are at high risk for nosocomial MDRO infections. The distributions of the other species did not differ significantly. The proportion of negative results was significantly higher in the nonbypass group.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of Bile Culture Results\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePathogen\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBypass group\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNonbypass group\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTotal (n\u0026thinsp;=\u0026thinsp;74)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePositive Result (n, %)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e78.1% (25/32)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e45.2% (19/42)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e59.5% (44/74)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eEscherichia coli\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.03\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eEnterococcus faecium\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eAcinetobacter baumannii\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eKlebsiella pneumoniae\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eCitrobacter freundii\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eEnterobacter cloacae\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eAeromonas hydrophila\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eStaphylococcus epidermidis\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.75\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eStaphylococcus haemolyticus\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eStreptococcus spp\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eCandida glabrata\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003ecandida albicans\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eEnterococcus faecalis\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNegative Result (n, %)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.4. Antimicrobial use and the severe challenge of resistance\u003c/h2\u003e\u003cp\u003eIn addition to the higher infection rate, both the antimicrobial use rate and the MDRO infection rate were significantly higher in the bypass group than in the non bypass group.\u003c/p\u003e\u003cp\u003eIn terms of drug selection, cefoperazone-sulbactam was the most frequently used agent in both groups, but its use was more prevalent in the bypass group. More critically, the combined use proportion of carbapenems, as last-line agents, was significantly higher in the bypass group. This reflects the clinical tendency to opt for broad-spectrum, potent antibiotics due to concerns about resistance in postbypass infections, also implying more severe resistance in this patient group.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eAntibiotic use and multidrug-resistant organism status\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIndicator\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBypass group (n\u0026thinsp;=\u0026thinsp;32)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNonbypass group (n\u0026thinsp;=\u0026thinsp;42)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ep value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAntibiotic Use Rate (n, %)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e78.1%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e54.8%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCefoperazone-sulbactam\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.03\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eImipenem-cilastatin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.04\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMeropenem\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.05\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMDRO Infection (n, %)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e46.9%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003e3.5. Clinical outcomes and healthcare resource utilization\u003c/h2\u003e\u003cp\u003eA history of biliary-enteric bypass had a clear negative impact on final clinical outcomes. Although the length of stay was not different at baseline, the adjusted hospitalization duration considering infections and other complications was significantly longer in the bypass group (28.5 vs. 25.7 days, p\u0026thinsp;=\u0026thinsp;0.04). Concurrently, this group bore a heavier economic burden, with average total costs higher than those of the nonbypass group (8.9 vs. 7.6, p\u0026thinsp;=\u0026thinsp;0.02) (ten thousand CNY). These data collectively indicate that a history of biliary-enteric bypass is an independent risk factor for a worse prognosis and higher healthcare costs in patients with biliary tract infections.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis study, through systematic comparative analysis, clearly reveals the multiple challenges faced by patients post biliary-enteric bypass regarding biliary infection pathogenesis, the inflammatory response, antimicrobial resistance, and clinical prognosis, providing key insights for optimizing management strategies for this specific population.\u003c/p\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e4.1. Biliary\u0026ndash;enteric bypass reshapes the biliary microecology: From a sterile environment to a bacterial reservoir\u003c/h2\u003e\u003cp\u003eThe markedly high bile culture positivity rate of 78.1% in the bypass group, in stark contrast with 45.2% in the nonbypass group, strongly confirms that biliary-enteric bypass is a powerful promoter of biliary bacterial colonization[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The root cause is the loss of the anatomical barrier. The physiological function of the sphincter of Oddi is replaced by anastomosis, allowing the duodenal contents, including billions of intestinal microbes, to continuously or intermittently reflux into the biliary tree[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Our pathogen spectrum analysis\u0026mdash;showing high detection rates of \u003cem\u003eE. coli\u003c/em\u003e and \u003cem\u003eE. faecium\u003c/em\u003e\u0026mdash;closely aligns with the gut microbiota, perfectly supporting this \"enteric origin\" theory[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe colonization of \u003cem\u003eEnterococcus faecium\u003c/em\u003e warrants particular attention. The detection rate of 21.9% in the bypass group was significantly higher than that in the control group, suggesting that the postreconstruction biliary environment may be particularly conducive to the survival and proliferation of these resistant enterococci[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The biofilm-forming capability of enterococci might allow them to persist on foreign bodies such as stents or anastomotic sites, leading to chronic, recurrent infections that respond poorly to conventional therapy[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eFurthermore, the predominant detection of \u003cem\u003eAcinetobacter baumannii\u003c/em\u003e in the bypass group shifted from simple gut flora translocation to the acquisition and spread of nosocomial MDROs. These bacteria are not dominant in the gut flora; their high prevalence is more likely associated with multiple hospitalizations, invasive procedures, and long-term exposure to broad-spectrum antimicrobials[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. This finding indicates that the postbypass biliary tract can become not only a \"target\" for infection but also a \"reservoir\" and \"source\" for MDRO dissemination.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003e4.2. Systemic inflammatory response: The barometer of infection risk and prognostic warning\u003c/h2\u003e\u003cp\u003eThis study revealed that patients in the bypass group already presented significantly elevated WBC, CRP, and PCT levels upon admission. These markers reflect the severity of infection at different levels. Their concurrent elevation strongly suggests a more active and widespread infectious-inflammatory process in bypass group patients.\u003c/p\u003e\u003cp\u003eThis persistent inflammatory state stems not only from local bacterial infection in the biliary tract but also from the continuous entry of bacterial products into the bloodstream[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. It is not only a basis for diagnosing infection but also a key mechanism contributing to poor outcomes. Therefore, dynamically monitoring these inflammatory markers is crucial for assessing severity, predicting sepsis risk, and evaluating treatment efficacy.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003e4.3. The dilemma of antimicrobial therapy: The vicious cycle of high usage and high resistance\u003c/h2\u003e\u003cp\u003eFacing higher infection rates and more complex pathogens, the bypass group inevitably received more frequent and broader-spectrum antimicrobial therapy. This study revealed a significantly higher proportion of carbapenem use in this group. While this is a rational choice for suspected or confirmed MDRO infections, the selective pressure from broad-spectrum antibiotics further selects for and enriches resistant strains, exacerbating the resistance problem[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe observed 46.9% MDRO infection rate in the bypass group is a direct manifestation of this vicious cycle. Breaking this cycle is paramount.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e4.4. Optimizing clinical management strategies: From empiricism to precision, from anti-infection to comprehensive management\u003c/h2\u003e\u003cp\u003eOn the basis of these findings, we propose the following multilevel management recommendations: (1) Strengthening pathogen-directed precision therapy: For all postbypass patients showing signs of biliary infection, bile should be obtained for culture and susceptibility testing before initiating antimicrobial therapy whenever possible. Long-term empirical use or \"escalation\" therapy without indication should be strictly avoided. De-escalation to narrow-spectrum, targeted agents should be prompt once susceptibilities are available. (2) Addressing the MDRO challenge: For MDRO infections, consider combination regimens on the basis of susceptibility results. (3) Nonantibiotic prevention and control measures should be emphasized, with a focus on reducing the bacterial load and blocking transmission through refined surgical techniques, postoperative regular biliary flushing, and strict aseptic protocols. Exploring the value of local antibiotic infusion in specific high-risk populations might offer new strategies to reduce systemic drug use and resistance risk. (4) Comprehensively enhancing patient innate resistance: Active nutritional support is fundamental to improving overall outcomes and reducing infection susceptibility.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\u003ch2\u003e4.5. Study limitations and future directions\u003c/h2\u003e\u003cp\u003eAs a single-center retrospective analysis, this study has inherent limitations. The sample size may affect the statistical power for analysing rare pathogens or outcomes. The retrospective design cannot fully control for all potential confounders. Future prospective, multicenter, large-scale cohort studies are needed. More importantly, future research should move beyond traditional culture methods by integrating metagenomic sequencing to reveal the true landscape of the biliary microbiome in an unbiased manner and identify uncultivable organisms and community functional features associated with infection. These findings will open new avenues for understanding pathogenesis and developing novel microecological interventions.\u003c/p\u003e\u003c/div\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThis study, through detailed data analysis, confirms that patients with a history of biliary-enteric bypass present a distinct clinical profile compared with those without a history: significantly higher biliary bacterial colonization rates, a pathogen spectrum dominated by gram-negative bacilli and enterococci, higher detection rates of nosocomial MDROs such as \u003cem\u003eA. baumannii\u003c/em\u003e, significantly elevated systemic inflammatory markers indicating more severe infection, higher antimicrobial use rates, MDRO infection rates, and reliance on last-line agents such as carbapenems, and ultimately, a more severe clinical prognosis manifested by prolonged hospitalization and increased costs.\u003c/p\u003e\u003cp\u003eThese findings alert clinicians to manage postbiliary-enteric bypass patients as a very high-risk group for biliary tract and MDRO infections. The core of management lies in combining \"prevention\" and \"treatment\": preventing infection through optimized surgical and drainage techniques and strict asepsis, effectively treating infection, curbing resistance, and ultimately improving patient outcomes through enhanced pathogen surveillance, precision antimicrobial use, and comprehensive nutritional support.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eThis study was approved by the ethics\u0026nbsp;committee of the Affiliated BenQ Hospital of Nanjing Medical University (Approval No. 2024-KL012) in accordance with national regulations and the Helsinki Declaration.\u003c/p\u003e\n\u003cp\u003eAnd informed consent was obtained from the participant included in the study.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eInformed consent was obtained from the patient for publication of the \u0026nbsp;report and any accompanying \u0026nbsp;images.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAvailability of data and material\u003c/p\u003e\n\u003cp\u003eAll the data and materials are presented in this manuscript.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eNo.\u003c/p\u003e\n\u003cp\u003eAuthors' contributions\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDXG and YM designed the research. DXG collected the data, JJT and WJG performed the analysis. DXG prepared the manuscript draft. All the authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eNot Applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eArshad SA, Phuoc VH. Surgical palliation of biliary obstruction: Bypass in the era of drainage. J Surg Oncol. 2019;120(1):65\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKaplan GG, Gregson DB, Laupland KB. Population-based study of the epidemiology of and the risk factors for pyogenic liver abscess. Clin Gastroenterol Hepatol. 2004;2:1032\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChuang JH, Chen WJ, Lee SY, Chang NK. Prompt colonization of the hepaticojejunostomy and translocation of bacteria to liver after bile duct reconstruction. 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Epidemiology and outcomes of vancomycin-resistant enterococcus infections: a systematic review and meta-analysis. J Hosp Infect. 2023;141:119\u0026ndash;28.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKubin CJ, Garzia C, Uhlemann A-C. Acinetobacter baumannii treatment strategies: a review of therapeutic challenges and considerations. Antimicrob Agents Chemother. 2025;69(8):e0106324.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChaves F, Garnacho-Montero J, Del Pozo JL et al. Diagnosis and treatment of catheter-related bloodstream infection: Clinical guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology and (SEIMC) and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC). Med Intensiva (Engl Ed). 2018 Jan-Feb;42(1):5\u0026ndash;36.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFornari V, Accardo G, Lupia T. Suppressive antibiotic treatment (SAT) in the era of MDRO infections: a narrative review. Expert Rev Anti Infect Ther. 2025;23(5):291\u0026ndash;303.\u003c/span\u003e\u003c/li\u003e\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":"bmc-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bsur","sideBox":"Learn more about [BMC Surgery](http://bmcsurg.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bsur/default.aspx","title":"BMC Surgery","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Biliary‒enteric bypass, Biliary tract infections, Multidrug-resistant organism","lastPublishedDoi":"10.21203/rs.3.rs-8035459/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8035459/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBackground: Biliary‒enteric bypass surgery, while relieving obstruction, disrupts the anatomical barrier of the biliary system, predisposing patients to biliary infections. However, comprehensive comparative analyses of biliary pathogen profiles, inflammatory responses, and antimicrobial resistance in patients with and without a history of this surgery are limited. This study aimed to compare these aspects and their impact on clinical outcomes between these two patient groups.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMethods: A single-center retrospective study was conducted on 74 patients who underwent percutaneous transhepatic biliary drainage (PTBD) for biliary tract infections between October 2020 and May 2024. Patients were divided into biliary-enteric bypass (n = 32) and nonbypass (n = 42) groups on the basis of surgical history. Data on demographics, bile cultures, inflammatory markers, antibiotic use, and multidrug-resistant organism (MDRO) were analysed.\u003c/p\u003e\n\u003cp\u003eResults: The bypass group had a significantly higher bile culture positivity rate (78.1% vs. 45.2%, p \u0026lt; 0.01), with a predominance of \u003cem\u003eEscherichia coli\u003c/em\u003e (34.4%) and \u003cem\u003eEnterococcus faecium\u003c/em\u003e (21.9%). The MDRO infection rate was markedly higher in the bypass group (46.9% vs. 21.4%, p = 0.01), accompanied by higher use of carbapenems (25.0% vs. 18.8%, p = 0.04). Preoperative inflammatory marker levels were significantly elevated in the bypass group (p \u0026lt; 0.01). Clinically, the bypass group experienced longer hospital stays (28.5 vs. 25.7 days, p = 0.04) and higher total costs (8.9 vs. 7.6, p = 0.02) (ten thousand CNY).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConclusion: A history of biliary-enteric bypass is associated with a distinct and more severe biliary infection profile characterize;d by higher rates of bacterial colonization, MDROs, intense systemic inflammation, increased carbapenem reliance, and poorer clinical outcomes. These patients require intensified microbiological surveillance, prudent antibiotic stewardship, and comprehensive management strategies.\u003c/p\u003e","manuscriptTitle":"Analysis of biliary pathogens and clinical outcomes in patients with biliary tract infections on the basis of a history of biliary-enteric bypass: a single-center retrospective study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-08 10:00:01","doi":"10.21203/rs.3.rs-8035459/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-01-02T07:35:34+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-22T17:11:57+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-19T00:51:30+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"75417312738978893471392917630301897198","date":"2025-12-11T11:46:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"294533263532752709282003123775833887614","date":"2025-12-09T19:17:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"262216799747017018499224254719631650674","date":"2025-12-05T08:42:24+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-12-04T19:00:43+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-11-08T17:50:48+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-07T06:07:19+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-07T06:06:44+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Surgery","date":"2025-11-05T07:29:52+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bsur","sideBox":"Learn more about [BMC Surgery](http://bmcsurg.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bsur/default.aspx","title":"BMC Surgery","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f758d0ea-4c53-4dd8-9335-4a66afcdfeb7","owner":[],"postedDate":"December 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-02-16T16:06:53+00:00","versionOfRecord":{"articleIdentity":"rs-8035459","link":"https://doi.org/10.1186/s12893-026-03582-z","journal":{"identity":"bmc-surgery","isVorOnly":false,"title":"BMC Surgery"},"publishedOn":"2026-02-10 15:58:30","publishedOnDateReadable":"February 10th, 2026"},"versionCreatedAt":"2025-12-08 10:00:01","video":"","vorDoi":"10.1186/s12893-026-03582-z","vorDoiUrl":"https://doi.org/10.1186/s12893-026-03582-z","workflowStages":[]},"version":"v1","identity":"rs-8035459","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8035459","identity":"rs-8035459","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}