Analysis of the microbial spectrum of urinary tract infections and antibiotic resistance of UPEC in Central Inner Mongolia, China

Urinary Tract Infections (UTIs) remain a significant global health concern, with the pathogen spectrum and antibiotic resistance patterns critically influencing clinical management. This study aimed to analyze the microbial profile of UTIs from 2022 to 2024, focusing on <i>Escherichia coli</i> (<i>E. coli</i>), the predominant pathogen, by evaluating its antibiotic resistance phenotypes, biofilm formation capability, and mutations in <i>GyrA, ParC</i> and Plasmid-Mediated Quinolone Resistance (PMQR) genes prevalence. Midstream urine samples from UTI patients were collected and analyzed for microbial identification. <i>E. coli</i> isolates were tested for antibiotic susceptibility, particularly to levofloxacin, the most frequently used antibiotic in our hospital. Biofilm formation was assessed, and mutations in <i>GyrA, ParC</i> and PMQR genes were sequenced to determine resistance mechanisms.The pathogen spectrum revealed that <i>Enterobacteriaceae</i> were the most prevalent (44.42%), with <i>E. coli</i> being the dominant species. Over 70% of <i>E. coli</i> isolates exhibited resistance to levofloxacin, and 58.97% (46/78) demonstrated biofilm-forming ability. Among levofloxacin-resistant strains, 75.64% (59/78) showed high-level resistance (MIC ≥ 8μg/mL). The most common mutations in <i>GyrA</i> were Ser83Leu (89.74%) and Asp87Asn (71.79%), while Ser80Ile (74.36%) was predominant in <i>ParC</i>. PMQR genes were detected in 17.95% (14/78) of isolates. The elevated prevalence of quinolone-resistant <i>E. coli</i> in urinary tract infections within this region, combined with intricate resistance gene mutations and generally strong biofilm-forming capabilities, underscores the critical necessity for rational antibiotic stewardship.