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. Β-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.