PREVALENCE, PHYLOGENETIC DIVERSITY, AND ANTIMICROBIAL RESISTANCE OF UROPATHOGENIC ESCHERICHIA COLI IN GEORGIA.

BACKGROUND: Uropathogenic Escherichia coli (UPEC) represents the leading cause of urinary tract infections (UTIs) worldwide and remains a growing clinical concern due to increasing antimicrobial resistance. Data describing the molecular epidemiology of UPEC in Georgia are limited.

METHODS: Ninety E. coli isolates obtained from patients with genitourinary infections were analyzed. Species identification was confirmed by 16S rRNA gene sequencing. UPEC strains were identified by PCR detection of virulence-associated genes (c3509, c3686 (yrbH), and chuA). Phylogenetic grouping was performed using the Clermont multiplex PCR method. Antimicrobial susceptibility testing was carried out by disk diffusion in accordance with EUCAST guidelines.

RESULTS: Eighty-one isolates (90%) were classified as UPEC based on the presence of at least one virulence marker. Twenty-nine strains carried all three genes, whereas 22 harbored a single marker. Phylogenetic analysis demonstrated a predominance of group B2, with additional representation from groups A, B1, F, and clade I/II; several isolates remained unclassified. Resistance rates among UPEC strains were highest for trimethoprim (55%), ciprofloxacin (47%), and ceftriaxone (42%). Nitrofurantoin (5% resistance) and fosfomycin (3% resistance) remained highly effective. Notably, B2 strains exhibited higher frequencies of trimethoprim and ciprofloxacin resistance compared with non-B2 strains.

CONCLUSION: UPEC strains circulating in Georgia exhibit marked phylogenetic diversity but relatively low levels of multidrug resistance. Continued surveillance is warranted to support evidence-based antimicrobial therapy and stewardship.