Distribution and Antimicrobial Resistance Analysis of Blood Culture Isolates at a Chinese National Cardiovascular Regional Medical Center: A 7-Year Retrospective Study

Abstract

Purpose: This study aimed to characterize the epidemiological patterns and antimicrobial resistance profiles of bloodstream infections (BSIs) in a cardiovascular specialty hospital and to identify region-specific pathogen distributions, resistance risks, and clinical implications for optimizing empirical therapy and infection control strategies. Patients and Methods: A retrospective analysis (2018–2024) evaluated 1,055 non-duplicate BSI isolates from 37,576 blood cultures at the Fuwai Central China Cardiovascular Hospital. Researchers investigated both bacterial classification and associated drug resistance through comprehensive analysis. Results: The study revealed that a total of 1,055 bacterial strains were isolated from blood cultures, with Gram-negative bacteria accounting for 31.5% (332 strains), Gram-positive bacteria for 62.7% (662 strains), and fungi for 5.8% (61 strains). The most frequently isolated pathogens were Staphylococcus epidermidis (13.7%), Staphylococcus hominis (8.0%), Klebsiella pneumoniae (7.4%), Escherichia coli (7.1%), and Staphylococcus haemolyticus (6.7%). These pathogens were predominantly isolated from intensive care units (ICUs), with the Coronary Heart Disease ICU (24.7%), General ICU (18.0%), and Adult Cardiac Surgery ICU (8.1%) representing the top three departments for bacterial detection. Among Staphylococcus isolates, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococci (MRCNS) were identified at rates of 51.6% and 88.7%, respectively. The carbapenem resistance rates of K. pneumoniae and E. coli were 28.8% and 4.0%, respectively. Non-fermenting Gram-negative bacilli, such as Acinetobacter baumannii, showed alarming resistance rates to carbapenems (60.0%) and other β-lactams (≥52%), while Burkholderia cepacia and Stenotrophomonas maltophilia remained highly susceptible to first-line agents. Conclusion: Blood culture isolates in our hospital demonstrated a predominance of Gram-positive organisms, with high detection rates of MRSA, MRCNS, and carbapenem-resistant Gram-negative bacilli. Continuous antimicrobial resistance surveillance of bloodstream isolates should be maintained in clinical practice to provide evidence-based data for rational antibiotic use and mitigate the emergence of resistant pathogens.