Distribution and Antibiotic Resistance Analysis of Bloodstream Infection Pathogens in Yibin, Sichuan

To determine the distribution and antimicrobial resistance patterns of bloodstream infection (BSI) pathogens in Yibin, China, and to provide evidence for optimizing local empirical therapy and infection-control strategies.

A retrospective study was performed on 4431 non-duplicate bloodstream isolates recovered from 32569 patients at Yibin Second People's Hospital between January 2017 and December 2024. Organisms were identified and tested for antimicrobial susceptibility by Kirby-Bauer disk diffusion or VITEK-2 Compact. Antibiotic resistance to selected agents (eg polymyxins, vancomycin) were evaluated by broth micro-dilution and analysed based on CLSI M100-S34.

Gram-negative bacteria became the dominant isolates (51.4%), with their proportion significantly increasing during the study period. The main pathogens were Escherichia coli (27.4%), coagulase-negative Staphylococci (CoNS, 20.4% combined), and Klebsiella pneumoniae (9.7%). Among Enterobacteriaceae, ESBL-producing E. coli was highly prevalent (63.6%), and carbapenem-resistant K. pneumoniae (CRKP) emerged at 8.7%. Critically, Acinetobacter baumannii showed extensive drug resistance, with carbapenem resistance at 62.1-65.3% and carbapenem-resistant isolates (CRAB) exhibiting >70% resistance to most tested agents. Among Gram-positive pathogens, while methicillin resistance in CoNS was high (78%), no resistance to vancomycin or linezolid was detected in any Staphylococcus or Enterococcus isolate.

Bloodstream infections in Yibin are increasingly dominated by Gram-negative organisms, with ESBL-producing E. coli and multidrug-resistant A. baumannii posing critical therapeutic challenges. Continuous local surveillance and antimicrobial stewardship are imperative to optimize empirical therapy and improve patient outcomes.