Community-acquired Pseudomonas aeruginosa pneumonia in immunocompetent children: a study of 7 cases

Community-acquired Pseudomonas aeruginosa pneumonia in immunocompetent children: a study of 7 cases | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Community-acquired Pseudomonas aeruginosa pneumonia in immunocompetent children: a study of 7 cases Fuce Lu, Yan Li, Xun Chen, Yiyu Chen, Chunyan Li, Guangmin Nong, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8846164/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Background To characterize the clinical features and outcomes of community-acquired Pseudomonas aeruginosa (PA) pneumonia in immunocompetent children. Methods A retrospective analysis was conducted of the detailed clinical data from seven cases of community-acquired PA pneumonia in immunocompetent children, who were hospitalized in the Department of Pediatrics at the First Affiliated Hospital of Guangxi Medical University between January 2015 to June 2025. Results All patients were male (n = 7). Age distribution was as follows: 1–12 months (n = 3), 13–36 months (n = 1), 37–60 months (n = 1), and ≥ 61 months (n = 2). Median age at onset was 18.0 months (IQR: 8.0–123.0). All patients presented acutely with fever and cough; two developed respiratory failure within 72 hours. Additional clinical features included dyspnea (n = 4), lung rales (n = 4), hemoptysis (n = 3), chest pain (n = 2), and wheezing (n = 1). Chest imaging showed lobar consolidation (n = 5) or mass-like consolidation (n = 2). PA was cultured from five patients. All isolates were susceptible to anti-pseudomonal β-lactam antibiotics except aztreonam. Complications included definite or suspected empyema (n = 5), pyopneumothorax (n = 3), and bacteremia (n = 2). Three patients required pediatric intensive care, two received invasive mechanical ventilation, two underwent closed thoracic drainage, and one required decortication. There were no deaths, but four patients sustained significant pulmonary damage. Conclusion Although rare, community-acquired PA pneumonia in immunocompetent children is associated with severe disease and pulmonary complications. Initial therapy with anti-pseudomonal β-lactam antibiotics appears effective in improving outcomes. community-acquired pseudomonas aeruginosa immunocompetent lobar consolidation empyema Figures Figure 1 Introdution Community-acquired pneumonia (CAP) is defined as an infectious pneumonia that is acquired in the community setting. It is a prevalent condition worldwide and is one of the most common causes of hospitalization in children. A variety of pathogens can result in CAP in children. Viruses like respiratory syncytial virus (RSV) are the common pathogens of CAP in children, especially in infants and toddlers.[ 1 ] Unlike viruses, atypical pathogens such as Mycoplasma pneumoniae (MP) usually cause CAP in children above 5 years of age.[ 1 ] Whereas bacteria can cause CAP in children of all ages.[ 1 ] The common bacteria resulting in CAP in children are Streptococcus pneumoniae and Haemophilus influenzae.[ 2 ] Pseudomonas aeruginosa (PA) is widespread in the environment and is recognized as an opportunistic human pathogen.[ 3 ] It readily infects hospital and immunocompromised patients and is known to cause chronic airway infections in patients with bronchiectasis, particularly those with cystic fibrosis (CF).[ 3 ] Although rare, it can also lead to CAP in immunocompetent children.[ 4 ] To date, only individual case reports have been published and comprehensive studies exploring this disease in detail remain limited. In this report, we present seven cases of community-acquired PA pneumonia in immunocompetent children to extend clinicians’ awareness and improve the diagnostic and therapeutic accuracy regarding this condition. Subjects and Methods Subjects In this study, the cases of community-acquired PA pneumonia were screened from our pediatric pneumonia database between January 2015 and June 2025. Cases with an immunocompromised state, structural lung diseases, tracheobronchial abnormalities, gene-variant-related diseases such as primary ciliary dyskinesia (PCD) and CF, or mixed infections were excluded. Finally, a total of seven cases were included. Study design The detailed clinical data of the included seven cases were collected by the medical record review, including the general information (gender and the age of onset), clinical manifestations, the performance of chest imaging, laboratory findings, complications, treatments and outcomes. Additionally, a follow-up of the cases was performed telephonically or through outpatient visits. Etiological diagnosis of Pseudomonas aeruginosa infection The etiological diagnosis of PA infection was confirmed by identification of the pathogens from qualified specimens of deep sputum, bronchoalveolar lavage fluid (BALF), pleural effusion or lung tissue using bacterial culture, metagenomics next-generation sequencing (mNGS) or targeted next-generation sequencing (tNGS). Ethics approval The Ethics Committee of the First Affiliated Hospital of Guangxi Medical University (2025-E0885) reviewed and approved this study. Statistical analysis SPSS 25.0 software was used to perform statistical analysis. Measurement data were presented as medians (25th-75th percentile), while counting data were expressed as counts (percentages). Results General information All the included patients (n = 7) were male. The age of onset varied with three cases between 1 to 12 months, one case between 13 to 36 months, one case between 37 to 60 months and two cases older than or equal to 61 months. The median age at onset was 18.0 (8.0, 123.0) months. Five cases experienced prodromal respiratory infections within 3 months before the community-acquired PA pneumonia (Table 1 ). Table 1 Clinical data of community-acquired pseudomonas aeruginosa pneumonia in immunocompetent children No. Gender Age of onset (months) Chest image Peripheral WBC CRP (mg/L) PCT (ng/ml) Pleural involement Bacteremia PICU IMV Destroyed lung Anti-infective strategy Prodromal respiratory virus infection 1 M 8 lobar consolidation in the right lower lobe leukocytosis 184.7 3.55 suspected empyema N N N Y CFP-SUL Y 2 M 178 mass-like consolidation in the left upper and lower lobes Normal 39.8 0.06 Pleural effusion N N N Y CFP-SUL N 3 M 123 mass-like consolidation in the right lower lobe leukocytosis 16.8 0.08 N N N N Y CFP-SUL Y 4 M 62 lobar consolidation in the right lobe leucopenia 187.2 8.73 pyopneumothorax Y Y Y Y MEM (initial), changed to CAZ + LEV, CAZ + AMK, CAZ-AVI + FOS successively Y 5 M 18 lobar consolidation in the left lower lobe leukocytosis > 192.0 10.30 definite empyema Y N N N CFP-SUL (initial), changed to TZP + AMK Y 6 M 3 lobar consolidation in the right lower lobe leukocytosis > 200.0 19.44 pyopneumothorax N Y N N CFP-SUL (initial), changed to MEM, TZP successively N 7 M 8 lobar consolidation in the bilateral upper lobes and left lower lobe leucopenia 224 100.00 pyopneumothorax N Y Y N MEM (initial), changed to CFP-SUL Y CFP-SUL: cefoperazone-sulbactam; MEM: meropenem; TZP: piperacillin-tazobactam; AMK: amikacin; CAZ: ceftazidime; LEV: levofloxacin; CAZ-AVI: ceftazidime-avibactam; FOS: fosfomycin; IMV: invasive mechanical ventilation; WBC: white blood cells Clinical manifestations and complications All cases (n = 7) presented with an acute onset characterized by fever and cough, with 2 cases rapidly progressing to respiratory failure within 3 days of symptom onset. Additional clinical manifestations included dyspnea (n = 4), lung rales (n = 4), hemoptysis (n = 3), chest pain (n = 2) and wheezing (n = 1). Intrathoracic complications were prevalent, comprising definite or suspected empyema (n = 5) and pyopneumothorax (n = 3). In addition, pulmonary-origin PA bacteremia was found in two cases (Table 1 ). Complementary examinations Chest imaging revealed two types of radiological appearances, namely lobar (n = 5) and mass-like consolidation (n = 2). All cases (n = 7) presented with a predominance of the involvement of the lower lobe. In addition, pleural involvement (n = 6) was common. Both leukocytosis (n = 4) and leucopenia (n = 2) were observed. All cases (n = 7) exhibited increased C-reactive protein (CRP) levels and 5 cases revealed increased procalcitonin (PCT) levels (Table 1 and Fig. 1 ). Etiological diagnosis and drug-susceptibility test (DST) results A total of 5 cases were culture positive for PA. According to the initial DST results, all were susceptible to the anti-PA β-lactam agents (except aztreonam), aminoglycoside and fluoroquinolone. During the treatment, four cases had repeated DST results. Of these, antimicrobial resistance was induced in three cases: carbapenem resistance, induced by carbapenem resistance to traditional non-carbapenem anti-PA β-lactam agents, in two cases; and resistance to fluoroquinolones, in one case. Notably, no resistance to aminoglycosides was induced (Table 2 ). Table 2 The results of drug sensitivity tests in this study NO. Detection time Specimens Ttraditional noncarbapenem anti-PA β-lactam agents Carbapenem Fluoroquinolone Aminoglycoside Polymycin CAZ CP CFP-SUL ATM TZP MEM IMP CIP LEV AMK TL PMB 1 initial deep sputum S S S S S S S S S S S I 4 initial deep sputum S S S I S S S S S S S R repeated deep sputum R R I S S R R R R S S I 5 initial blood S S S S S S S S S S S S repeated pleural effusion S S S S S S S S S S S S 6 initial deep sputum S S S S S S S S S S S S repeated pleural effusion S S S S S I R S S S S S 7 initial deep sputum S S S I S S S S S S S S repeated pleural effusion I S S I I R R S S S S S PA: pseudomonas aeruginosa; CAZ: ceftazidime; CP: cefepime; CFP-SUL: cefoperazone-sulbactam; ATM: aztreonam; TZP: piperacillin-tazobactam; MEM: meropenem; IMP: imipenem; CIP: ciprofloxacin; LEV: levofloxacin; AMK: amikacin; TL:tobramycin; PMB: polymycin B Treatments and prognosis All the cases (n = 7) were initially treated using anti-PA β-lactam agents. Of these, four cases were initially treated with traditional non-carbapenem anti-PA β-lactam agents, in which three cases were resolved without a change of anti-infective strategy and one case needed a change of anti-infective strategy. The remaining three cases were initially treated with intravenous meropenem. In contrast, all the cases needed a change in anti-infective strategy (Table 1 ). Of these, three cases were admitted to the intensive care unit, and two cases required invasive mechanical ventilation. Among the cases with a definite or likely diagnosis of empyema (n = 6), three received drainage in the acute stage and one received empyemectomy in the chronic stage (Table 1 ). The median length of hospital stay was 29 (22, 60) days. None cases died, but 4 cases had significantly destroyed lungs on chest imaging (Table 1 ). Discussion Incidence and risk factors PA is a common nosocomial pathogen and typically infects children with underlying medical conditions, such as immunodeficiency or structural lung diseases. In contrast, community-acquired PA pneumonia in immunocompetent children is relatively rare. To the best of our knowledge, the first report in English literature on community-acquired PA pneumonia in immunocompetent children was published in 2022.[ 4 ] Since then, only a few cases have been reported. The risk factors for PA infection in immunocompetent children remain largely unknown; however, prodromal respiratory infections, particularly those caused by viruses, appear to be a potential risk factor for PA infection. This is supported by reports of PA co-infection with respiratory viruses.[ 5 , 6 ] In this study, 71.4% (5/7) of the cases experienced a prodromal respiratory infection within 3 months before the community-acquired PA pneumonia. Viral infections can compromise the airway mucosal barrier,[ 7 ] which may facilitate PA infection. Additionally, several studies have indicated that the onset of community-acquired PA pneumonia in adult patients is associated with the use of household humidifiers and hydrotherapy equipment.[ 8 ] However, nebulizer and environmental samples could not be obtained from the subjects in this study. Clinical manifestations and complications In this study, all cases showed an acute onset, with the disease progressing rapidly, leading to respiratory failure in two cases within 3 days of the disease onset. The observation indicates that PA-CAP in immunocompetent children is marked by an acute onset and could progress rapidly, similar to findings in adult cases. From 2010 to 2022, a total 12 cases of PA-CAP in immunocompetent adults have been reported.[ 9 ] Of these, 75.0% (9/12) needed intensive care and 33.0% (4/12) died in a short period.[ 9 ] The clinical symptoms of PA-CAP in immunocompetent children appeared non-specific compared to the typical causes of CAP in children; However, PA-CAP was more likely to have hemoptysis linked to lung tissue destruction. In this study, 42.6% (3/7) of the cases demonstrated hemoptysis. Of these adult cases, 50.0% (6/12) had hemoptysis.[ 9 ] In addition, the first pediatric case reported in 2022 exhibited hemoptysis.[ 4 ] Intrathoracic complications were prevalent in PA-CAP in immunocompetent children, with 85.7% (6/7) of the cases experiencing intrathoracic complications. In addition, pulmonary-originated PA bacteremia was found in 28.6% (2/7) of the cases. Notably, it was more common in adult cases. Of these adult cases, 58.3% (7/12) also had PA bacteremia.[ 9 ] Complementary examinations In this study, two types of radiological appearance (lobar and mass-like consolidation) were observed in the PA-CAP in immunocompetent children. Lobar consolidation was more common and found in 71.4% (5/7) of the cases compared to mass-like consolidation. The majority of the cases (4/5) with lobar consolidation were at a younger age (less than 24 months), which was different from the common bacterial cause of CAP in children. In the latter, the development of lobar consolidation primarily relied on the diffusion along the alveolar pores, which was completely developed by 8 years of age.[ 10 ] Therefore, lobar consolidation is more common in cases at an older age, and cases at a younger age usually present as lobular pneumonia.[ 11 ] PA might cause lobular pneumonia owing to high invasiveness in pediatric cases, rather than diffusion along the alveolar pores, which results in lobar consolidation. Both leukocytosis and leucopenia were observed in the PA-CAP in immunocompetent children in this study. It was in accordance with the literature on adult cases.[ 9 ] Of the reported 12 adult cases, 41.7% (5/12) presented with leukocytosis, while 41.7% (5/12) presented with leucopenia. The first pediatric case reported in 2022 also presented leukocytosis.[ 4 ] Leukocytosis with a left shift usually suggests bacterial infection and is considered a response to bacterial infection, contributing to rapid inherent immunological defense. Leucopenia post-infection has been linked to an excessive inflammatory response, even overwhelming septic shock.[ 12 , 13 ] It was in accordance with our study. In this study, the disease in both cases with leucopenia progressed rapidly, resulting in respiratory failure and the necessity for invasive mechanical ventilation in a short period of time. However, the detailed mechanisms underlying leucopenia post-infection remain ambiguous. Drug sensitivity analysis In this study, a total of five cases were culture-positive for PA. According to the initial drug-susceptibility-test results, all were susceptible to the anti-PA β-lactam agents (except aztreonam), aminoglycoside and fluoroquinolone. This was in accordance with the drug sensitivity characteristic of community-acquired infection. PA is resistant to many classes of antibiotics due to the intrinsic, acquired, and genetic factors. Of these, antibiotic applications are the primary driver of the emergence of antimicrobial-resistant PA.[ 14 ] Antibiotics can cause enormous selective pressure by killing PA or inhibiting its growth, leading to the development of drug resistance. The results of the study by Philippe et al. indicated that the median time from exposure to effective antibiotics to isolation of MDR strains of PA was 11 days.[ 15 ] In this study, four cases were culture-positive for PA repeatedly after antibiotic application. Of these, antimicrobial resistance was induced in 3 cases. Carbapenem resistance was induced in all three cases with carbapenem treatment. In the first pediatric case reported in 2022, carbapenem resistance was also induced after carbapenem treatment.[ 4 ] In addition, resistance to the traditional non-carbapenem anti-PA β-lactam agents was induced in two cases, and fluoroquinolone resistance was induced in one case. Therefore, repeated culture and drug sensitivity analysis should be performed during the anti-PA treatment. The antimicrobial treatment strategy might be adjusted according to the drug sensitivity test if the infection is recurrent or uncontrolled. Treatments In children, anti-PA β-lactam agents, including penicillin, cephalosporins, and carbapenems, are commonly used against PA, in which penicillin and cephalosporins are referred to as the traditional non-carbapenem anti-PA β-lactam agents.[ 16 ] Fluoroquinolones, aminoglycosides, or polymyxins are not routinely used in children against PA due to the potential adverse drug effects. In this study, all cases were initially treated with anti-PA β-lactam agents. Among the 4 cases initially treated with the traditional non-carbapenem anti-PA β-lactam agents, three achieved resolution without a change in anti-infective strategy, while one required a modification in treatment. All the cases initially treated with carbapenems needed a change in anti-infective strategy. The traditional non-carbapenem anti-PA β-lactam agents against PA were more effective than carbapenems. However, it may also be because the doctors were more willing to choose carbapenems as an initial treatment in severe cases. The anti-infective strategy might need to be adjusted due to the high risk of carbapenem resistance after carbapenem treatment. Empyema was common in the PA-CAP in immunocompetent children. In this study, 71.4% (5/7) of the cases were definitely or most likely diagnosed as empyema. The treatment of empyema primarily aims to drain the pleural cavity to provide re-expansion of the compressed lung, to control the infection with appropriate antibiotic therapy, and to prevent complications.[ 17 ] Drainage by thoracentesis, tube thoracostomy or decortication (thoracoscopy or open thoracotomy) is sometimes necessary.[ 18 ] In this study, 60.0% (3/5) of the cases with a definite or likely diagnosis of empyema received drainage in the acute stage, and 1 case received empyemectomy in the chronic stage. The antibiotic course was long and required a long time to recover in patients with PA-CAP. In this study, the median length of hospital stay was approximately 1 month. The adult cases were discharged after a median recovery of 24 days and the median recovery of patients discharged after intensive care was 30 days.[ 9 ] In addition, the first pediatric case reported needed 32 days of hospitalization.[ 4 ] Prognosis of the PA-CAP in immunocompetent children Although PA-CAP was rare, it was usually severe, even fatal, in immunocompetent subjects. Of the reported adult cases, 75.0% (7/12) needed intensive care and 33.0% (4/12) died.[ 9 ] In this study, 42.9% (3/7) of the cases needed intensive care, and 25.6% (2/7) required invasive mechanical ventilation. Fortunately, no case died in this study. Pulmonary sequelae due to the PA-CAP should be given attention, as 57.1% (4/7) of the cases had significantly destroyed lungs on chest imaging in this study. Therefore, regular follow-up is required. Limitations The interpretation of our findings should consider several limitations: (1) the retrospective design may introduce selection and information bias; (2) the small sample size, while reflecting the disease's rarity, limits statistical power; (3) being a single-center study affects generalizability; and (4) the lack of environmental sampling limits etiological insights into exposure sources. Conclusion Community-acquired PA pneumonia is uncommon, but usually severe in children. Initial treatment using anti-PA β-lactam antibiotics seems to be effective. Abbreviations PA：Pseudomonas aeruginosa；CAP：Community-acquired pneumonia ；RSV：respiratory syncytial virus ；MP：mycoplasma pneumoniae ；CF：cystic fibrosis ；PCD：primary ciliary dyskinesia ; BALF: bronchoalveolar lavage fluid ; mNGS:metagenomics next-generation sequencing ; tNGS: targeted next-generation sequencing ; CRP: C-reactive protein ; PCT:procalcitonin ；DST：drug-susceptibilty-test Declarations Acknowledgements This study would like to thank the participants who gave their time to contribute to this study. Funding All phases of this study were supported by Guangxi Clinical Research Center for Pediatric disease (NO: AD22035219), the National Natural Science Foundation of Guangxi (2025GXNSFAA069702) and Key Laboratory of Children's Disease Research in Guangxi’s Colleges and Universities, Education Department of Guangxi Zhuang Autonomous Region. Author contributions Drs Qing Wei and Jing Liu conceptualized and designed the study, drafted the initial manuscript, and critically reviewed and revised the manuscript. Drs Fuce Lu and Yan Li designed the data collection instruments, collected data, carried out the initial analyses, drafted the initial manuscript,and critically reviewed and revised the manuscript. Yiyu Chen designed the data collection instruments, collected data, carried out the initial analyses, and critically reviewed and revised the manuscript. Chunyan Li and Guangmin Nong designed the study, coordinated and supervised data collection, and critically reviewed and revised the manuscript for important intellectual content. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work. Data availability No datasets were generated or analysed during the current study. Ethics approval and consent to participate This study was approved by the Ethics Committee of The First Affiliated Hospital of Guangxi Medical University and was conducted in accordance with the Declaration of Helsinki. Given the retrospective and anonymized nature of this study, the requirement for informed consent was waived by the aforementioned ethics committee. Competing interests The authors declare no competing interests. References Meyer Sauteur PM. Childhood community-acquired pneumonia. Eur J Pediatrics. 2023;183(3):1129–36. Yun KW. Community-acquired pneumonia in children: updated perspectives on its etiology, diagnosis, and treatment. Clin Experimental Pediatr. 2024;67(2):80–9. Jurado-Martín I, Sainz-Mejías M, McClean S. Pseudomonas aeruginosa: An audacious pathogen with an adaptable arsenal of virulence factors. Int J Mol Sci. 2021;22(6):3128. Dong C, Shen F, Dong H, Dong L, Fu Y, Xu Y, Ning J. 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Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 05 May, 2026 Reviews received at journal 02 May, 2026 Reviewers agreed at journal 28 Apr, 2026 Reviews received at journal 26 Apr, 2026 Reviewers agreed at journal 23 Apr, 2026 Reviewers agreed at journal 09 Apr, 2026 Reviewers invited by journal 17 Mar, 2026 Editor invited by journal 10 Mar, 2026 Editor assigned by journal 15 Feb, 2026 Submission checks completed at journal 15 Feb, 2026 First submitted to journal 10 Feb, 2026 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. We do this by developing innovative software and high quality services for the global research community. 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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-8846164","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":607422855,"identity":"5621aca6-dcea-4c11-8d79-1332c2f14b63","order_by":0,"name":"Fuce Lu","email":"","orcid":"","institution":"First Affiliated Hospital of GuangXi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Fuce","middleName":"","lastName":"Lu","suffix":""},{"id":607422856,"identity":"2eb752b0-85c8-4e65-a536-be5d4282bcf9","order_by":1,"name":"Yan Li","email":"","orcid":"","institution":"First Affiliated Hospital of GuangXi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yan","middleName":"","lastName":"Li","suffix":""},{"id":607422858,"identity":"e0dd04a9-e1f1-4a51-9a9c-e70372807485","order_by":2,"name":"Xun Chen","email":"","orcid":"","institution":"First Affiliated Hospital of GuangXi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xun","middleName":"","lastName":"Chen","suffix":""},{"id":607422860,"identity":"fac68e92-0ee0-4802-9fc4-0e55580eb0b0","order_by":3,"name":"Yiyu Chen","email":"","orcid":"","institution":"First Affiliated Hospital of GuangXi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yiyu","middleName":"","lastName":"Chen","suffix":""},{"id":607422863,"identity":"4b87f9db-2267-4a65-98b4-1020b2594a04","order_by":4,"name":"Chunyan Li","email":"","orcid":"","institution":"the First Affiliated Hospital of Guangxi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Chunyan","middleName":"","lastName":"Li","suffix":""},{"id":607422864,"identity":"03aa4cef-36ba-462a-b892-7c8fa63bb94a","order_by":5,"name":"Guangmin Nong","email":"","orcid":"","institution":"First Affiliated Hospital of GuangXi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Guangmin","middleName":"","lastName":"Nong","suffix":""},{"id":607422866,"identity":"b449a55c-bd68-4473-8b98-e374aa8b1628","order_by":6,"name":"Jing Liu","email":"","orcid":"","institution":"First Affiliated Hospital of GuangXi Medical University","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Liu","suffix":""},{"id":607422870,"identity":"071d107b-288f-45b2-9055-ac722107e762","order_by":7,"name":"Qing Wei","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7ElEQVRIiWNgGAWjYFACxgaGBAYGHjb+5oMPEiok5PiJ1SLHL3Es2eDDGQtjyQYi7QKqzDGTnNlWkbiBkBaD482NNx7uqE3ccOCMmTTvPAnGDQzMDx/dwKflzMFmi8QzxxM3HG4rtubdJsFszsBmbJyDR4vZjcQ2icS2Y0BbDm+8DdTCZtnAwyaNV8v9hzAtCQbSvHMkeAwOENJygxGkpQbo/RQjyZkNEhIEtdifSQT6pe0ANJCPSRhINhPwi2T78Yc3f7bVQaOypq6+n7354WN8WkBAgoHhMBKXmYByqJY6IpSNglEwCkbBiAUA5/5U0DDit4cAAAAASUVORK5CYII=","orcid":"","institution":"First Affiliated Hospital of GuangXi Medical University","correspondingAuthor":true,"prefix":"","firstName":"Qing","middleName":"","lastName":"Wei","suffix":""}],"badges":[],"createdAt":"2026-02-11 02:08:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8846164/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8846164/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104998312,"identity":"3ef6a3ba-2ab9-4f20-a295-5b141b802ce4","added_by":"auto","created_at":"2026-03-19 16:26:20","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":364792,"visible":true,"origin":"","legend":"\u003cp\u003eChest image of community-acquired pseudomonas aeruginosa pneumonia in immunocompetent children. A: showed mass-like consolidation in the right lower lobe in case 3. B: showed cystic changes 8 months later in the same case to A. C: showed lobar consolidation in the left lower lobe in case 5. D: showed absorption of the lesions 2 months later in the same case to C.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8846164/v1/ab22a0355b22c5b84113b636.png"},{"id":104998323,"identity":"0d4f41f0-87fc-49cd-90e2-fe4beb358745","added_by":"auto","created_at":"2026-03-19 16:26:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1342722,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8846164/v1/62832ff2-0d28-4f08-b4a0-246795120cc1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Community-acquired Pseudomonas aeruginosa pneumonia in immunocompetent children: a study of 7 cases","fulltext":[{"header":"Introdution","content":"\u003cp\u003eCommunity-acquired pneumonia (CAP) is defined as an infectious pneumonia that is acquired in the community setting. It is a prevalent condition worldwide and is one of the most common causes of hospitalization in children. A variety of pathogens can result in CAP in children. Viruses like respiratory syncytial virus (RSV) are the common pathogens of CAP in children, especially in infants and toddlers.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] Unlike viruses, atypical pathogens such as Mycoplasma pneumoniae (MP) usually cause CAP in children above 5 years of age.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] Whereas bacteria can cause CAP in children of all ages.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] The common bacteria resulting in CAP in children are Streptococcus pneumoniae and Haemophilus influenzae.[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] Pseudomonas aeruginosa (PA) is widespread in the environment and is recognized as an opportunistic human pathogen.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] It readily infects hospital and immunocompromised patients and is known to cause chronic airway infections in patients with bronchiectasis, particularly those with cystic fibrosis (CF).[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] Although rare, it can also lead to CAP in immunocompetent children.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] To date, only individual case reports have been published and comprehensive studies exploring this disease in detail remain limited. In this report, we present seven cases of community-acquired PA pneumonia in immunocompetent children to extend clinicians\u0026rsquo; awareness and improve the diagnostic and therapeutic accuracy regarding this condition.\u003c/p\u003e"},{"header":"Subjects and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSubjects\u003c/h2\u003e \u003cp\u003eIn this study, the cases of community-acquired PA pneumonia were screened from our pediatric pneumonia database between January 2015 and June 2025. Cases with an immunocompromised state, structural lung diseases, tracheobronchial abnormalities, gene-variant-related diseases such as primary ciliary dyskinesia (PCD) and CF, or mixed infections were excluded. Finally, a total of seven cases were included.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStudy design\u003c/h3\u003e\n\u003cp\u003eThe detailed clinical data of the included seven cases were collected by the medical record review, including the general information (gender and the age of onset), clinical manifestations, the performance of chest imaging, laboratory findings, complications, treatments and outcomes. Additionally, a follow-up of the cases was performed telephonically or through outpatient visits.\u003c/p\u003e\n\u003ch3\u003eEtiological diagnosis of Pseudomonas aeruginosa infection\u003c/h3\u003e\n\u003cp\u003eThe etiological diagnosis of PA infection was confirmed by identification of the pathogens from qualified specimens of deep sputum, bronchoalveolar lavage fluid (BALF), pleural effusion or lung tissue using bacterial culture, metagenomics next-generation sequencing (mNGS) or targeted next-generation sequencing (tNGS).\u003c/p\u003e\n\u003ch3\u003eEthics approval\u003c/h3\u003e\n\u003cp\u003e The Ethics Committee of the First Affiliated Hospital of Guangxi Medical University (2025-E0885) reviewed and approved this study.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eSPSS 25.0 software was used to perform statistical analysis. Measurement data were presented as medians (25th-75th percentile), while counting data were expressed as counts (percentages).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eGeneral information\u003c/h2\u003e \u003cp\u003eAll the included patients (n\u0026thinsp;=\u0026thinsp;7) were male. The age of onset varied with three cases between 1 to 12 months, one case between 13 to 36 months, one case between 37 to 60 months and two cases older than or equal to 61 months. The median age at onset was 18.0 (8.0, 123.0) months. Five cases experienced prodromal respiratory infections within 3 months before the community-acquired PA pneumonia (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\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\u003eClinical data of community-acquired pseudomonas aeruginosa pneumonia in immunocompetent children\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"14\"\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=\"char\" char=\".\" 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=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAge of onset\u003c/p\u003e \u003cp\u003e(months)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChest image\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePeripheral WBC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCRP\u003c/p\u003e \u003cp\u003e(mg/L)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003ePCT\u003c/p\u003e \u003cp\u003e(ng/ml)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003ePleural involement\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eBacteremia\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003ePICU\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003eIMV\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003eDestroyed lung\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e \u003cp\u003eAnti-infective strategy\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c14\"\u003e \u003cp\u003eProdromal respiratory virus infection\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003elobar consolidation in the right lower lobe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eleukocytosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e184.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003esuspected empyema\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eCFP-SUL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e178\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003emass-like consolidation in the left upper and lower lobes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNormal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e39.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003ePleural effusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eCFP-SUL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e123\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003emass-like consolidation in the right lower lobe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eleukocytosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e16.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eCFP-SUL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003elobar consolidation in the right lobe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eleucopenia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e187.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e8.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003epyopneumothorax\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eMEM (initial), changed to CAZ\u0026thinsp;+\u0026thinsp;LEV, CAZ\u0026thinsp;+\u0026thinsp;AMK, CAZ-AVI\u0026thinsp;+\u0026thinsp;FOS successively\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003elobar consolidation in the left lower lobe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eleukocytosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;192.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003edefinite empyema\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eCFP-SUL (initial), changed to TZP\u0026thinsp;+\u0026thinsp;AMK\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003elobar consolidation in the right lower lobe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eleukocytosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;200.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e19.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003epyopneumothorax\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eCFP-SUL (initial), changed to MEM, TZP successively\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003elobar consolidation in the bilateral upper lobes and left lower lobe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eleucopenia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e224\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e100.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003epyopneumothorax\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eMEM (initial), changed to CFP-SUL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eY\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"14\"\u003eCFP-SUL: cefoperazone-sulbactam; MEM: meropenem; TZP: piperacillin-tazobactam; AMK: amikacin; CAZ: ceftazidime; LEV: levofloxacin; CAZ-AVI: ceftazidime-avibactam; FOS: fosfomycin; IMV: invasive mechanical ventilation; WBC: white blood cells\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eClinical manifestations and complications\u003c/h3\u003e\n\u003cp\u003eAll cases (n\u0026thinsp;=\u0026thinsp;7) presented with an acute onset characterized by fever and cough, with 2 cases rapidly progressing to respiratory failure within 3 days of symptom onset. Additional clinical manifestations included dyspnea (n\u0026thinsp;=\u0026thinsp;4), lung rales (n\u0026thinsp;=\u0026thinsp;4), hemoptysis (n\u0026thinsp;=\u0026thinsp;3), chest pain (n\u0026thinsp;=\u0026thinsp;2) and wheezing (n\u0026thinsp;=\u0026thinsp;1). Intrathoracic complications were prevalent, comprising definite or suspected empyema (n\u0026thinsp;=\u0026thinsp;5) and pyopneumothorax (n\u0026thinsp;=\u0026thinsp;3). In addition, pulmonary-origin PA bacteremia was found in two cases (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eComplementary examinations\u003c/h2\u003e \u003cp\u003eChest imaging revealed two types of radiological appearances, namely lobar (n\u0026thinsp;=\u0026thinsp;5) and mass-like consolidation (n\u0026thinsp;=\u0026thinsp;2). All cases (n\u0026thinsp;=\u0026thinsp;7) presented with a predominance of the involvement of the lower lobe. In addition, pleural involvement (n\u0026thinsp;=\u0026thinsp;6) was common. Both leukocytosis (n\u0026thinsp;=\u0026thinsp;4) and leucopenia (n\u0026thinsp;=\u0026thinsp;2) were observed. All cases (n\u0026thinsp;=\u0026thinsp;7) exhibited increased C-reactive protein (CRP) levels and 5 cases revealed increased procalcitonin (PCT) levels (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eEtiological diagnosis and drug-susceptibility test (DST) results\u003c/h2\u003e \u003cp\u003eA total of 5 cases were culture positive for PA. According to the initial DST results, all were susceptible to the anti-PA β-lactam agents (except aztreonam), aminoglycoside and fluoroquinolone. During the treatment, four cases had repeated DST results. Of these, antimicrobial resistance was induced in three cases: carbapenem resistance, induced by carbapenem resistance to traditional non-carbapenem anti-PA β-lactam agents, in two cases; and resistance to fluoroquinolones, in one case. Notably, no resistance to aminoglycosides was induced (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\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\u003eThe results of drug sensitivity tests in this study\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"15\"\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=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNO.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDetection time\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSpecimens\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c8\" namest=\"c4\"\u003e \u003cp\u003eTtraditional noncarbapenem anti-PA β-lactam agents\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003eCarbapenem\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c12\" namest=\"c11\"\u003e \u003cp\u003eFluoroquinolone\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003eAminoglycoside\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c15\"\u003e \u003cp\u003ePolymycin\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCAZ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCFP-SUL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eATM\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eTZP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eMEM\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eIMP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003eCIP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003eLEV\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e \u003cp\u003eAMK\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c14\"\u003e \u003cp\u003eTL\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c15\"\u003e \u003cp\u003ePMB\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003einitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003edeep sputum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003einitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003edeep sputum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003erepeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003edeep sputum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003einitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eblood\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003erepeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003epleural effusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003einitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003edeep sputum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003erepeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003epleural effusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003einitial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003edeep sputum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003erepeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003epleural effusion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"15\"\u003ePA: pseudomonas aeruginosa; CAZ: ceftazidime; CP: cefepime; CFP-SUL: cefoperazone-sulbactam; ATM: aztreonam; TZP: piperacillin-tazobactam; MEM: meropenem; IMP: imipenem; CIP: ciprofloxacin; LEV: levofloxacin; AMK: amikacin; TL:tobramycin; PMB: polymycin B\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eTreatments and prognosis\u003c/h2\u003e \u003cp\u003eAll the cases (n\u0026thinsp;=\u0026thinsp;7) were initially treated using anti-PA β-lactam agents. Of these, four cases were initially treated with traditional non-carbapenem anti-PA β-lactam agents, in which three cases were resolved without a change of anti-infective strategy and one case needed a change of anti-infective strategy. The remaining three cases were initially treated with intravenous meropenem. In contrast, all the cases needed a change in anti-infective strategy (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOf these, three cases were admitted to the intensive care unit, and two cases required invasive mechanical ventilation. Among the cases with a definite or likely diagnosis of empyema (n\u0026thinsp;=\u0026thinsp;6), three received drainage in the acute stage and one received empyemectomy in the chronic stage (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe median length of hospital stay was 29 (22, 60) days. None cases died, but 4 cases had significantly destroyed lungs on chest imaging (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eIncidence and risk factors\u003c/h2\u003e \u003cp\u003ePA is a common nosocomial pathogen and typically infects children with underlying medical conditions, such as immunodeficiency or structural lung diseases. In contrast, community-acquired PA pneumonia in immunocompetent children is relatively rare. To the best of our knowledge, the first report in English literature on community-acquired PA pneumonia in immunocompetent children was published in 2022.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] Since then, only a few cases have been reported. The risk factors for PA infection in immunocompetent children remain largely unknown; however, prodromal respiratory infections, particularly those caused by viruses, appear to be a potential risk factor for PA infection. This is supported by reports of PA co-infection with respiratory viruses.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] In this study, 71.4% (5/7) of the cases experienced a prodromal respiratory infection within 3 months before the community-acquired PA pneumonia. Viral infections can compromise the airway mucosal barrier,[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] which may facilitate PA infection. Additionally, several studies have indicated that the onset of community-acquired PA pneumonia in adult patients is associated with the use of household humidifiers and hydrotherapy equipment.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] However, nebulizer and environmental samples could not be obtained from the subjects in this study.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eClinical manifestations and complications\u003c/h2\u003e \u003cp\u003eIn this study, all cases showed an acute onset, with the disease progressing rapidly, leading to respiratory failure in two cases within 3 days of the disease onset. The observation indicates that PA-CAP in immunocompetent children is marked by an acute onset and could progress rapidly, similar to findings in adult cases. From 2010 to 2022, a total 12 cases of PA-CAP in immunocompetent adults have been reported.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] Of these, 75.0% (9/12) needed intensive care and 33.0% (4/12) died in a short period.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] The clinical symptoms of PA-CAP in immunocompetent children appeared non-specific compared to the typical causes of CAP in children; However, PA-CAP was more likely to have hemoptysis linked to lung tissue destruction. In this study, 42.6% (3/7) of the cases demonstrated hemoptysis. Of these adult cases, 50.0% (6/12) had hemoptysis.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] In addition, the first pediatric case reported in 2022 exhibited hemoptysis.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] Intrathoracic complications were prevalent in PA-CAP in immunocompetent children, with 85.7% (6/7) of the cases experiencing intrathoracic complications. In addition, pulmonary-originated PA bacteremia was found in 28.6% (2/7) of the cases. Notably, it was more common in adult cases. Of these adult cases, 58.3% (7/12) also had PA bacteremia.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eComplementary examinations\u003c/h2\u003e \u003cp\u003eIn this study, two types of radiological appearance (lobar and mass-like consolidation) were observed in the PA-CAP in immunocompetent children. Lobar consolidation was more common and found in 71.4% (5/7) of the cases compared to mass-like consolidation. The majority of the cases (4/5) with lobar consolidation were at a younger age (less than 24 months), which was different from the common bacterial cause of CAP in children. In the latter, the development of lobar consolidation primarily relied on the diffusion along the alveolar pores, which was completely developed by 8 years of age.[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] Therefore, lobar consolidation is more common in cases at an older age, and cases at a younger age usually present as lobular pneumonia.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] PA might cause lobular pneumonia owing to high invasiveness in pediatric cases, rather than diffusion along the alveolar pores, which results in lobar consolidation.\u003c/p\u003e \u003cp\u003eBoth leukocytosis and leucopenia were observed in the PA-CAP in immunocompetent children in this study. It was in accordance with the literature on adult cases.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] Of the reported 12 adult cases, 41.7% (5/12) presented with leukocytosis, while 41.7% (5/12) presented with leucopenia. The first pediatric case reported in 2022 also presented leukocytosis.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] Leukocytosis with a left shift usually suggests bacterial infection and is considered a response to bacterial infection, contributing to rapid inherent immunological defense. Leucopenia post-infection has been linked to an excessive inflammatory response, even overwhelming septic shock.[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] It was in accordance with our study. In this study, the disease in both cases with leucopenia progressed rapidly, resulting in respiratory failure and the necessity for invasive mechanical ventilation in a short period of time. However, the detailed mechanisms underlying leucopenia post-infection remain ambiguous.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eDrug sensitivity analysis\u003c/h2\u003e \u003cp\u003eIn this study, a total of five cases were culture-positive for PA. According to the initial drug-susceptibility-test results, all were susceptible to the anti-PA β-lactam agents (except aztreonam), aminoglycoside and fluoroquinolone. This was in accordance with the drug sensitivity characteristic of community-acquired infection. PA is resistant to many classes of antibiotics due to the intrinsic, acquired, and genetic factors. Of these, antibiotic applications are the primary driver of the emergence of antimicrobial-resistant PA.[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] Antibiotics can cause enormous selective pressure by killing PA or inhibiting its growth, leading to the development of drug resistance. The results of the study by Philippe et al. indicated that the median time from exposure to effective antibiotics to isolation of MDR strains of PA was 11 days.[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] In this study, four cases were culture-positive for PA repeatedly after antibiotic application. Of these, antimicrobial resistance was induced in 3 cases. Carbapenem resistance was induced in all three cases with carbapenem treatment. In the first pediatric case reported in 2022, carbapenem resistance was also induced after carbapenem treatment.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] In addition, resistance to the traditional non-carbapenem anti-PA β-lactam agents was induced in two cases, and fluoroquinolone resistance was induced in one case. Therefore, repeated culture and drug sensitivity analysis should be performed during the anti-PA treatment. The antimicrobial treatment strategy might be adjusted according to the drug sensitivity test if the infection is recurrent or uncontrolled.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eTreatments\u003c/h2\u003e \u003cp\u003eIn children, anti-PA β-lactam agents, including penicillin, cephalosporins, and carbapenems, are commonly used against PA, in which penicillin and cephalosporins are referred to as the traditional non-carbapenem anti-PA β-lactam agents.[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] Fluoroquinolones, aminoglycosides, or polymyxins are not routinely used in children against PA due to the potential adverse drug effects. In this study, all cases were initially treated with anti-PA β-lactam agents. Among the 4 cases initially treated with the traditional non-carbapenem anti-PA β-lactam agents, three achieved resolution without a change in anti-infective strategy, while one required a modification in treatment. All the cases initially treated with carbapenems needed a change in anti-infective strategy. The traditional non-carbapenem anti-PA β-lactam agents against PA were more effective than carbapenems. However, it may also be because the doctors were more willing to choose carbapenems as an initial treatment in severe cases. The anti-infective strategy might need to be adjusted due to the high risk of carbapenem resistance after carbapenem treatment.\u003c/p\u003e \u003cp\u003eEmpyema was common in the PA-CAP in immunocompetent children. In this study, 71.4% (5/7) of the cases were definitely or most likely diagnosed as empyema. The treatment of empyema primarily aims to drain the pleural cavity to provide re-expansion of the compressed lung, to control the infection with appropriate antibiotic therapy, and to prevent complications.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] Drainage by thoracentesis, tube thoracostomy or decortication (thoracoscopy or open thoracotomy) is sometimes necessary.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] In this study, 60.0% (3/5) of the cases with a definite or likely diagnosis of empyema received drainage in the acute stage, and 1 case received empyemectomy in the chronic stage.\u003c/p\u003e \u003cp\u003eThe antibiotic course was long and required a long time to recover in patients with PA-CAP. In this study, the median length of hospital stay was approximately 1 month. The adult cases were discharged after a median recovery of 24 days and the median recovery of patients discharged after intensive care was 30 days.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] In addition, the first pediatric case reported needed 32 days of hospitalization.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003ePrognosis of the PA-CAP in immunocompetent children\u003c/h2\u003e \u003cp\u003eAlthough PA-CAP was rare, it was usually severe, even fatal, in immunocompetent subjects. Of the reported adult cases, 75.0% (7/12) needed intensive care and 33.0% (4/12) died.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] In this study, 42.9% (3/7) of the cases needed intensive care, and 25.6% (2/7) required invasive mechanical ventilation. Fortunately, no case died in this study. Pulmonary sequelae due to the PA-CAP should be given attention, as 57.1% (4/7) of the cases had significantly destroyed lungs on chest imaging in this study. Therefore, regular follow-up is required.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eThe interpretation of our findings should consider several limitations: (1) the retrospective design may introduce selection and information bias; (2) the small sample size, while reflecting the disease's rarity, limits statistical power; (3) being a single-center study affects generalizability; and (4) the lack of environmental sampling limits etiological insights into exposure sources.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eCommunity-acquired PA pneumonia is uncommon, but usually severe in children. Initial treatment using anti-PA β-lactam antibiotics seems to be effective.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003ePA：Pseudomonas aeruginosa；CAP：Community-acquired pneumonia\u0026nbsp;；RSV：respiratory syncytial virus\u0026nbsp;；MP：mycoplasma pneumoniae\u0026nbsp;；CF：cystic fibrosis\u0026nbsp;；PCD：primary ciliary dyskinesia ;\u0026nbsp;BALF: bronchoalveolar lavage fluid ; mNGS:metagenomics next-generation sequencing ; tNGS: targeted next-generation sequencing ; CRP: C-reactive protein ; PCT:procalcitonin ；DST：drug-susceptibilty-test\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study would like to thank the participants who gave their time to contribute to this study.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll phases of this study were supported by Guangxi Clinical Research Center for Pediatric disease (NO: AD22035219), the National Natural Science Foundation of Guangxi (2025GXNSFAA069702) and Key Laboratory of Children\u0026apos;s Disease Research in Guangxi\u0026rsquo;s Colleges and Universities, Education Department of Guangxi Zhuang Autonomous Region. \u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDrs Qing Wei and Jing Liu conceptualized and designed the study, drafted the initial manuscript, and critically reviewed and revised the manuscript.\u003c/p\u003e\n\u003cp\u003eDrs Fuce Lu and Yan Li designed the data collection instruments, collected data, carried out the initial analyses, drafted the initial manuscript,and critically reviewed and revised the manuscript.\u003c/p\u003e\n\u003cp\u003eYiyu Chen designed the data collection instruments, collected data, carried out the initial analyses, and critically reviewed and revised the manuscript.\u003c/p\u003e\n\u003cp\u003eChunyan Li and Guangmin Nong designed the study, coordinated and supervised data collection, and critically reviewed and revised the manuscript for important intellectual content.\u003c/p\u003e\n\u003cp\u003eAll authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.\u003c/p\u003e\n\n\u003cp\u003eData availability\u003c/p\u003e\n\n\u003cp\u003eNo datasets were generated or analysed during the current study.\u003c/p\u003e\n\n\n\n\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethics Committee of The First Affiliated Hospital of Guangxi Medical University and was conducted in accordance with the Declaration of Helsinki. Given the retrospective and anonymized nature of this study, the requirement for informed consent was waived by the aforementioned ethics committee.\u003c/p\u003e\n\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eMeyer Sauteur PM. Childhood community-acquired pneumonia. Eur J Pediatrics. 2023;183(3):1129\u0026ndash;36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYun KW. Community-acquired pneumonia in children: updated perspectives on its etiology, diagnosis, and treatment. Clin Experimental Pediatr. 2024;67(2):80\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJurado-Mart\u0026iacute;n I, Sainz-Mej\u0026iacute;as M, McClean S. Pseudomonas aeruginosa: An audacious pathogen with an adaptable arsenal of virulence factors. Int J Mol Sci. 2021;22(6):3128.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDong C, Shen F, Dong H, Dong L, Fu Y, Xu Y, Ning J. Community-acquired Pseudomonas aeruginosa pneumonia manifested by bloody pleural effusion in a previously healthy infant: A case report. J Clin Lab Anal. 2022;36(6):e24466.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJie F, Wu X, Zhang F, Li J, Liu Z, He Y, Li C, Zhang H, Lin Y, Zhu X. Influenza virus infection increases host susceptibility to secondary infection with pseudomonas aeruginosa, and this is attributed to neutrophil dysfunction through reduced myeloperoxidase activity. Microbiol Spectr. 2023;11(1):e03655\u0026ndash;03622.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCorreia LF, de Oliveira T, Anselmo CA, Gervasoni LF, Pereira VC, Winkelstroter LK. Clinical aspects and characterization of Pseudomonas aeruginosa isolated from patients infected with SARS-CoV-2. Microb Pathog. 2025;199:107273.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVilleret B, Solhonne B, Straube M, Lemaire F, Cazes A, Garcia-Verdugo I, Sallenave J-M. Influenza a virus pre-infection exacerbates Pseudomonas aeruginosa-mediated lung damage through increased MMP-9 expression, decreased elafin production and tissue resilience. Front Immunol. 2020;11:117.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWoods E, Cohen G, Bressman E, Lin D, Zeitouni NE, Beckford C, Hamula C, van Bakel H, Sullivan M, Altman DR. Community-acquired cavitary pseudomonas pneumonia linked to use of a home humidifier. Case Rep Infect Dis 2017, 2017(1):5474916.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarp N, Marcacci M, Biagioni E, Serio L, Busani S, Ventura P, Franceschini E, Orlando G, Venturelli C, Menozzi I. A fatal case of Pseudomonas aeruginosa community-acquired pneumonia in an immunocompetent patient: clinical and molecular characterization and literature review. Microorganisms. 2023;11(5):1112.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZinserling VA, Swistunov VV, Botvinkin AD, Stepanenko LA, Makarova AE. Lobar (croupous) pneumonia: old and new data. Infection. 2021;50(1):235\u0026ndash;42.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi Y, Han F, Yang Y, Chu J. Principles of antibiotic application in children with lobar pneumonia: Step-up or step-down. Experimental Therapeutic Med. 2017;13(6):2681\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChawla S, Jose T, Paul M. Critical care in obstetrics: Where are we. J Obstet Gynecol India. 2018;68(3):155\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu C, Muhataer X, Wang W, Deng M, Jin R, Lian Z, Luo D, Li Y, Yang X. Abnormal DNA methylation patterns in patients with infection\u0026ndash;caused leukocytopenia based on methylation microarrays. Mol Med Rep. 2020;21(6):2335\u0026ndash;48.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCill\u0026oacute;niz C, Gabarr\u0026uacute;s A, Ferrer M, de la Bellacasa JP, Rinaudo M, Mensa J, Niederman MS, Torres A. Community-acquired pneumonia due to multidrug-and non\u0026ndash;multidrug-resistant Pseudomonas aeruginosa. Chest. 2016;150(2):415\u0026ndash;25.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePhilippe E, Weiss M, Shultz JM, Yeomans F, Ehrenkranz NJ. Emergence of highly antibiotic-resistant Pseudomonas aeruginosa in relation to duration of empirical antipseudomonal antibiotic treatment. Clin Perform Qual health care. 1999;7(2):83\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTamma PD, Heil EL, Justo JA, Mathers AJ, Satlin MJ, Bonomo RA. Infectious Diseases Society of America 2024 guidance on the treatment of antimicrobial-resistant gram-negative infections. Clin Infect Dis 2024:ciae403.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKuru M. Empyema in children. Turkish J Thorac Cardiovasc Surg. 2024;32(Supplementum 1):29\u0026ndash;36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShiraishi Y, Omasa M, Yamashita S, Hyung-Eun Y, Tanahashi M, Fukami T, Tokyooka S, Ode Y, Okamoto T, Shiraishi T. Guidelines for the treatment of empyema (The Japanese Association for Chest Surgery). Gen Thorac Cardiovasc Surg. 2025;73(5):312\u0026ndash;27.\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":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-infectious-diseases","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"infd","sideBox":"Learn more about [BMC Infectious Diseases](http://bmcinfectdis.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/infd","title":"BMC Infectious Diseases","twitterHandle":"#bmcinfectdis","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"community-acquired, pseudomonas aeruginosa, immunocompetent, lobar consolidation, empyema","lastPublishedDoi":"10.21203/rs.3.rs-8846164/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8846164/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eTo characterize the clinical features and outcomes of community-acquired Pseudomonas aeruginosa (PA) pneumonia in immunocompetent children.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective analysis was conducted of the detailed clinical data from seven cases of community-acquired PA pneumonia in immunocompetent children, who were hospitalized in the Department of Pediatrics at the First Affiliated Hospital of Guangxi Medical University between January 2015 to June 2025.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAll patients were male (n\u0026thinsp;=\u0026thinsp;7). Age distribution was as follows: 1\u0026ndash;12 months (n\u0026thinsp;=\u0026thinsp;3), 13\u0026ndash;36 months (n\u0026thinsp;=\u0026thinsp;1), 37\u0026ndash;60 months (n\u0026thinsp;=\u0026thinsp;1), and \u0026ge;\u0026thinsp;61 months (n\u0026thinsp;=\u0026thinsp;2). Median age at onset was 18.0 months (IQR: 8.0\u0026ndash;123.0). All patients presented acutely with fever and cough; two developed respiratory failure within 72 hours. Additional clinical features included dyspnea (n\u0026thinsp;=\u0026thinsp;4), lung rales (n\u0026thinsp;=\u0026thinsp;4), hemoptysis (n\u0026thinsp;=\u0026thinsp;3), chest pain (n\u0026thinsp;=\u0026thinsp;2), and wheezing (n\u0026thinsp;=\u0026thinsp;1). Chest imaging showed lobar consolidation (n\u0026thinsp;=\u0026thinsp;5) or mass-like consolidation (n\u0026thinsp;=\u0026thinsp;2). PA was cultured from five patients. All isolates were susceptible to anti-pseudomonal β-lactam antibiotics except aztreonam. Complications included definite or suspected empyema (n\u0026thinsp;=\u0026thinsp;5), pyopneumothorax (n\u0026thinsp;=\u0026thinsp;3), and bacteremia (n\u0026thinsp;=\u0026thinsp;2). Three patients required pediatric intensive care, two received invasive mechanical ventilation, two underwent closed thoracic drainage, and one required decortication. There were no deaths, but four patients sustained significant pulmonary damage.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eAlthough rare, community-acquired PA pneumonia in immunocompetent children is associated with severe disease and pulmonary complications. Initial therapy with anti-pseudomonal β-lactam antibiotics appears effective in improving outcomes.\u003c/p\u003e","manuscriptTitle":"Community-acquired Pseudomonas aeruginosa pneumonia in immunocompetent children: a study of 7 cases","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-19 16:25:21","doi":"10.21203/rs.3.rs-8846164/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-05-05T12:32:57+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-02T18:04:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"293021713602480579010669188322029871141","date":"2026-04-28T09:44:46+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-26T11:36:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"170987171212727856584295885463642728434","date":"2026-04-23T10:05:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"15225533195960651407837055115918974070","date":"2026-04-09T09:04:36+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-17T07:59:01+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-03-10T20:59:01+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-16T01:03:54+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-16T01:02:31+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Infectious Diseases","date":"2026-02-11T01:56:12+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-infectious-diseases","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"infd","sideBox":"Learn more about [BMC Infectious Diseases](http://bmcinfectdis.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/infd","title":"BMC Infectious Diseases","twitterHandle":"#bmcinfectdis","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5b9e3bfd-9b40-4d7d-9c1a-4b03c25a0d32","owner":[],"postedDate":"March 19th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Revision requested","date":"2026-05-05T12:32:57+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-02T18:04:55+00:00","index":52,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-18T17:08:15+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-19 16:25:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8846164","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8846164","identity":"rs-8846164","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}