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

PURPOSE: 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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.