Distribution and antimicrobial resistance of uropathogens: a 6-year retrospective single-center study (2019-2024)

This study aimed to characterize the distribution of uropathogens in positive urine cultures, their antimicrobial resistance patterns, and epidemiological features from 2019 to 2024, providing evidence for rational empirical antimicrobial therapy. We retrospectively analyzed clinical urine specimens for pathogen identification using the VITEK MS system and conducted antimicrobial susceptibility testing with the VITEK-2 system and Kirby-Bauer method. Among 1,978 positive specimens, 70.3% were bacterial and 29.7% were fungal. The predominant bacterial pathogens were E. coli (35.1%) and K. pneumoniae (24.2%), while fungal isolates were dominated by C. albicans (64.9%). We also observed a notable increase in the intrinsically fluconazole-resistant C. krusei over the study period. E. coli showed low resistance to nitrofurantoin, amikacin, and piperacillin/tazobactam, but high resistance to ampicillin and fluoroquinolones. Over the six years, carbapenem resistance in E. coli declined steadily, while resistance in K. pneumoniae fluctuated, peaking at 59.4% in 2020, highlighting the need for ongoing surveillance. Our findings indicate that fluoroquinolones and ampicillin should be avoided as first-line agents, while nitrofurantoin, amikacin, and piperacillin/tazobactam are viable options for treating E. coli-associated positive urine cultures. Furthermore, the high and fluctuating carbapenem resistance in K. pneumoniae underscores the need for strengthened antimicrobial stewardship, including enhanced surveillance and tailored prescribing, to optimize empirical therapy, curb resistance, and improve clinical outcomes.