Distribution Features and Antimicrobial Resistance Trends of Clinical Pathogens: A Retrospective Study in a Tertiary Teaching Hospital in East China (2020−2024)

Purpose: To examine the distribution of clinical pathogens and their antimicrobial resistance trends in a hospital in East China to provide evidence for rational antibiotic use and infection control. Methods: We conducted a retrospective study of bacterial isolates from January 2020 to December 2024. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK 2 system. WHONET 5.6 and R software were used for data analysis. Statistical analyses included chi-square tests and trend tests. Results: A total of 8680 pathogenic isolates were collected. Gram-negative bacteria predominated (74.7%) over Gram-positive bacteria (25.3%). The primary specimens were urine (33.7%), sputum (25.3%), and secretions (19.4%). The leading pathogens were E. coli (28.4%), K. pneumoniae (12.8%), and P. aeruginosa (11.5%). The carbapenem resistance rate was less than 1.9% in Escherichia coli strains over five years. The rate for carbapenem resistant K. pneumoniae (CRKP) showed a significant increasing trend, rising from 9.4% in 2022 to 16.7% in 2024 (p< 0.05). CRKP rates were lower than national CHINET data. The imipenem resistance rate of Pseudomonas aeruginosa exhibited an upward trend from 2020 (24.2%) to 2023 (34.1%) (p< 0.05). A. baumannii maintained high resistance to imipenem (> 73%), exceeding national levels. The proportion of methicillin-resistant Staphylococcus aureus (MRSA) fluctuated over the course of the five years (26.9– 44.8%). No vancomycin-resistant Enterococcus (VRE) was detected. Conclusion: E. coli, K. pneumoniae , and P. aeruginosa were the predominant pathogens in this hospital. The rising and high resistance rates of CRKP and CRAB highlight the urgent need for enhanced antimicrobial stewardship. &Bgr;-lactamase, β-lactamase inhibitor combination preparations and carbapenems were recommended for susceptible strains of E. coli and K. pneumoniae . For CRKP infections and CRAB infections, tigecycline and colistin are recommended. Continuous surveillance and infection control are crucial to combat the evolving threat of multidrug-resistant organisms. Keywords: bacterial resistance surveillance, multi-drug resistant organism, rational application of antibiotics, hospital associated infection