Distribution and Antimicrobial Resistance Trends of Bloodstream Bacterial Isolates: A 10-year Single-Center Study in...

To analyze the changing distribution and drug resistance of pathogenic bacteria in patients with bloodstream infections (BSIs), thereby providing reference for hospital anti-infection treatment.

The clinical data, distribution of pathogenic bacteria and antimicrobial susceptibility profiles of patients with positive blood cultures at the First Affiliated Hospital of Xi'an Jiaotong University from January 1, 2015 to December 31, 2024 were collected retrospectively. WHONET 5.6 software was used for data analysis. The χ² test and Fisher exact test were used for statistical analysis.

A total of 9372 bacterial strains were isolated from blood cultures. Gram-negative bacterial predominated (66.8%), markedly surpassing Gram-positive bacterial (33.2%). The top five pathogens were Escherichia coli (30.1%), Klebsiella pneumoniae (15.8%), Enterococcus faecium (6.9%), coagulase-negative Staphylococci (6.3%) and Staphylococcus aureus (6.1%). The detection rate of methicillin-resistant Staphylococcus aureus ranged from 25.8% to 38.4%, and it remained susceptible to vancomycin, linezolid, and teicoplanin. The detection rate of methicillin-resistant coagulase-negative Staphylococci peaked at 77.7% to 82.4%. Enterococcus faecium showed resistance to ampicillin exceeding 75%, with resistance rates to vancomycin and linezolid increasing from 0% to 5.8% and 1.2%, respectively. Escherichia coli demonstrated high susceptibility to Carbapenems, with imipenem resistance remaining low (1.6-2.2%). The resistance rates of Klebsiella pneumoniae to imipenem rose from 3.2% to 25.6%.The resistance rate of carbapenem-resistant Pseudomonas aeruginosa decreased from 36.4% in 2015-2016 to 16.5% in 2023-2024. However, the resistance rate of carbapenem-resistant Acinetobacter baumannii significantly increased from 47.2% to 75.7% during the same period.

The pathogenic bacteria in blood cultures isolates at this hospital are predominantly Gram-negative, with Escherichia coli and Klebsiella pneumoniae being the most common pathogens. The increasing trends of carbapenem-resistant Klebsiella pneumoniae, Acinetobacter baumannii and methicillin-resistant coagulase-negative Staphylococci underscore the urgent need for enhanced surveillance of pathogen distribution and antimicrobial resistance in bloodstream infections to guide rational antimicrobial use.