Drug Resistance Patterns and Pathogen Distribution in Patients with Urinary Tract Infection in Suzhou, China: A Five-Year Retrospective Study (2020–2024)

Objective: To investigate the distribution of pathogens and their antimicrobial resistance profiles in urine cultures from patients with urinary tract infections (UTIs) in Suzhou, China, and to guide empirical treatment decisions. Methods: We analyzed 9,249 non-duplicate, positive midstream urine cultures collected from January 2020 to December 2024. Bacterial and fungal identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing (AST) was conducted following Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: Female patients (60.1%) and those aged > 65 years (64.3%) accounted for the majority of cases. Escherichia coli (33.3%) was the predominant pathogen followed by Enterococcus faecalis (8.6%), Klebsiella pneumoniae (8.4%), and Enterococcus faecium (8.0%). Its resistance to third/fourth-generation cephalosporins (eg, cefotaxime from 50.4% to 38.8%) decreased significantly ( P < 0.05), while resistance to fluoroquinolones remained high (> 60%). Carbapenem resistance in Klebsiella pneumoniae exhibited alarming fluctuations, peaking at 40.6% in 2023. The prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli decreased significantly. Enterococcus faecium displayed extreme resistance to ampicillin and fluoroquinolones (> 94%), whereas Enterococcus faecalis was more susceptible. Azole resistance in Candida albicans markedly declined but remained high in Candida tropicalis . Conclusion: Escherichia coli was the main bacterial urinary pathogen in the Suzhou region. The dynamically high carbapenem resistance in Klebsiella pneumoniae and the severe, species-specific resistance profile of Enterococcus faecium critically limited treatment options. Significant temporal changes in pathogen distribution and resistance patterns underscored the necessity for ongoing local surveillance, tailored empirical therapy, and reinforced antimicrobial stewardship programs to guide effective UTI management in the region. Keywords: urinary tract infection, pathogen distribution, antimicrobial resistance, carbapenem-resistant Klebsiella pneumoniae , empirical therapy