[Pathogen distribution and antimicrobial resistance in severe community-acquired bacterial pneumonia in the pediatric intensive care unit].
Objective: To analyze the pathogen distribution and antimicrobial resistance profiles of severe community-acquired bacterial pneumonia (SCABP) in children admitted to the pediatric intensive care unit (PICU). Methods: This retrospective cohort study included 308 children with SCABP treated at the PICU of Children's Hospital of Shanghai Jiao Tong University between January 2018 and December 2024. A total of 426 non-duplicate pathogenic bacteria were isolated from bronchoalveolar lavage fluid and sputum specimens. Antimicrobial susceptibility testing was performed for all isolates. Patients were stratified by admission year and the trends in isolation rates were tested using the Cochran-Armitage trend test. Results: A total of 426 non-duplicate pathogens were isolated from the 308 pediatric patients (178 males, 130 females), comprising 330 strains (77.5%) Gram-negative and 96 strains (22.5%) Gram-positive bacteria. The 5 most common organisms were: Acinetobacter baumannii (AB, 84 strains, 19.7%), Haemophilus influenzae (HI, 76 strains, 17.8%), Streptococcus pneumoniae (SP, 49 strains, 11.5%), Staphylococcus aureus (SA, 47 strains, 11.0%), and Pseudomonas aeruginosa (PA, 39 strains, 9.2%). Over the study period, HI emerged as the leading pathogen in 2024, with its isolation rate rising significantly from 8.3% (6/72) in 2018 to 36.1% (22/61) in 2024. In contrast, the isolation rates of AB and SP declined significantly from 33.3% (24/72) and 16.7% (12/72) in 2018 to 4.9% (3/61) and 1.6% (1/61) in 2024, respectively (χ2 for trend=18.75, 27.50, 9.50, all P<0.05). The overall resistance rates of HI to ampicillin, trimethoprim-sulfamethoxazole (TMP-SMZ), azithromycin, and cefuroxime were 72.4% (55/76), 71.1% (54/76), 63.2% (48/76), and 60.5% (46/76), respectively, while it remained fully susceptible to ceftriaxone. No PA isolates exhibited resistance to amikacin or piperacillin-tazobactam throughout the study. SP was universally resistant to erythromycin and clindamycin, with 71.4% (35/49) resistance to TMP-SMZ, while remaining fully susceptible to amoxicillin-clavulanate. SA had an 85.1% (40/47) resistance rate to penicillin, but retained complete susceptibility to vancomycin, linezolid, minocycline, tigecycline, TMP-SMZ, and rifampicin. Conclusions: Gram-negative bacteria predominate in SCABP among PICU patients. The pathogen spectrum has shifted significantly over time, with HI emerging as the predominant causative agent and exhibiting high resistance to multiple antibiotics. Ongoing surveillance and susceptibility-guided antibiotics selection are essential in clinical management.