Prevalence and antimicrobial resistance patterns in patients with urinary tract infections: a three-year retrospective study at a tertiary healthcare center in Lebanon

Urinary tract infections (UTIs) are among the most prevalent bacterial infections worldwide. The emergence of antibiotic resistance increasingly complicates their management. Therefore, this study aims to describe the prevalence and the resistance patterns of uropathogens isolated from patients having UTIs at a tertiary care center in Lebanon. We conducted a retrospective analysis of 39,837 urine cultures tested for UTIs, at a tertiary care center in South Lebanon, from 1st January 2022 to 31st December 2024. Data were collected from patients’ medical records. Urine cultures yielding ≥ 10⁵ CFU/mL of uropathogens were considered positive and further analyzed for antimicrobial susceptibility. The Chi-square test was used to evaluate the relationship between different categorical variables, and a p-value < 0.05 was considered statistically significant. Out of 39,837 urine cultures, only 17.09% were positive. Gram-negative bacteria were the most prevalent type (87.94%), with E. coli being the most predominant causative agent (66.67% of Gram-negative isolates). UTIs predominantly occurred in females and in adults aged 19–64 years, and both Gram-negative and Gram-positive uropathogens were found to be statistically significantly associated with gender and age groups. Over the three years, E. coli displayed a constant high resistance to ampicillin, a moderate resistance to third-generation cephalosporins, and a pronounced increase in resistance to aztreonam and amoxicillin-clavulanate. K. pneumoniae showed resistance to a wide range of antibiotics except for a few agents to which resistance was low. Other Gram-negative uropathogens exhibited species-specific resistance profiles. Among Gram-positives, Enterococcus spp. showed resistance against many antibiotics, with the highest being against ciprofloxacin, erythromycin, and tetracycline. Regarding Multi-Drug Resistant (MDR) bacteria, Extended-Spectrum Beta-Lactamase (ESBL)-producing E. coli was the only one among others that showed a marked increase in prevalence during the study period. This large, multi-year series demonstrates a high and increasing burden of Anti-Microbial Resistance (AMR) among uropathogens, which limits empiric oral treatment choices. Enhanced stewardship and updated antibiograms are urgently needed to guide therapy and limit multidrug resistance.