Molecular Characterization of Escherichia coli Causing Community-Acquired Urinary Tract Infections in a Suburban Area in West Bengal, India: Dispersal of Multidrug-Resistant Epidemic ST131 Clone Carrying CTX-M-1.

Antimicrobial resistance (AMR) imperils global public health overlooking the epidemiological situation of community-acquired infections, especially in low- and middle-income countries. We conducted this study in a suburban community in West Bengal, India, to comprehend the AMR and bacterial forensics of Escherichia coli causing community-acquired urinary tract infections (CAUTIs). Antibiograms, β-lactamases, plasmid-mediated quinolone resistance genes, and plasmids were investigated to explore AMR. Bacterial forensics was assessed using phylogrouping, genetic fingerprinting, and strain typing. Antibiograms revealed that > 75% of isolates had a multiple-antibiotic resistance (MAR) index of > 0.2. Fosfomycin remained 100% effective as an empiric drug, followed by nitrofurantoin (> 75%), aminoglycosides (> 65%), and co-trimoxazole (> 50%). Multidrug-resistant (MDR) was frequent (> 75%), with < 5% being extensively drug-resistant, including two colistin-resistant isolates. Piperacillin/tazobactam showed promising activity against the ESBL-producing isolates (> 70%) mostly carrying CTX-M-15 and TEM-1 (> 50%), which declined in the presence of OXA-1 (> 20%). TEM-253 and 254, two novel alleles, were assigned. Two of the thirteen NDM-5-producing carbapenem-resistant isolates co-harbored OXA-48. Among fluoroquinolone-resistant isolates (> 80%), aac(6')-lb-cr (> 20%) was the most common, followed by qnrS (> 10%). Plasmid of > 212 kb was prevalent (> 60%), especially in MDR isolates. IncF was the sole plasmid in > 85% of isolates, with > 90% having a MAR index > 0.2. Phylogroup B2 was prevalent (> 35%), primarily associated with the ESBL-producing ST131 clone (> 80%). Carbapenem-resistant isolates belonged to phylogroup A/sequence-type361, C/ST2851, D/ST405, and F/ST648. ESBL-producing isolates were largely clonally related. This maiden molecular study reveals the infiltration of MDR epidemic clones in a suburban community in eastern India, guiding genomic surveillance for strategic management of AMR at the national level.