Predominance of genetically diverse ESBL Escherichia coli identified in resistance mapping of Vembanad Lake, the largest fresh-cum-brackishwater lake of India

Abstract

Antimicrobial resistance (AMR) burden in Escherichia coli along the 90 km stretch of Vembanad Lake, Kerala, India was assessed. Seventy-seven percent of water samples drawn from 35 different stations of the Lake harbored E. coli. Antibiotic susceptibility test performed on 116 E. coli isolates revealed 81% were resistant to ≥ one antibiotic with 39 AMR profiles, 30% multidrug resistant, 32% extended spectrum  lactamase (ESBL) producers as per CLSI.The probability of isolating cefotaxime resistant E. coli was the highest 0.7 (P ≤ 0.05) in the Lake. Genetically diverse ESBL types blaTEM-116,blaCTX-M -152, blaCTX-M -27,blaCTX-M -55, blaCTX-M-205, and blaSHV-27 were identified. Molecular typing (ERIC PCR, MLST and PBRT) confirmed the diversity among E. coli between and within the stations. ST11439 and Single and Double Loci Variants of ST443, ST4533 were identified in Multi locus sequence typing (MLST) analysis. Inc plasmids (B/O, F, W, I1, FIIA, HI1, P-1, K/B and N) identified in the Lake evidences the transmission potential. Low multiple antibiotic resistance index (average < 0.2) indicating lower risk to the human population albeit, an emerging concern of ESBL resistance in the Lake. The occurrence of genetically variant ESBL E. coli in Vembanad Lake signals health hazards and necessitates pragmatizing strategic control measures.