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

Xiangtian Zhou,* Rong Hu,* Yuehua Xia, Xu Li, Shuangquan Nie, Tindong Li, Chao Chen, Bangdong Qi, Wenquan Li Department of Infectious Diseases, Second People’s Hospital of Yibin City, Yibin, Sichuan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Wenquan Li, Department of Infectious Diseases, Second People’s Hospital of Yibin City, Yibin, Sichuan Province, 644000, People’s Republic of China, Email [email protected]: 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.Keywords: blood flow infection, pathogenic bacteria, antibacterial, drug resistance