Prevalence of Extended-Spectrum Beta-Lactamase Resistance and CTX-M-Group 1 Gene in Escherichia coli from the Water and Sediment of Urbanized Mangrove Ecosystems of Kerala

The study aimed to determine the prevalence of extended-spectrum beta-lactamase resistance and CTX-M-group 1 gene in Escherichia coli from the water and sediment of three urbanized mangrove ecosystems of Kerala. A total of 119 E. coli isolates were screened for antibiotic susceptibility to 16 antibiotics. According to the phylogenetic analysis of E. coli isolates, nonpathogenic group A and pathogenic group D (29.4% and 23.5%) were the predominant phylotypes found in water samples. The most frequent phylotypes found in sediment samples were nonpathogenic groups A and B1 (27.9% and 26.4%). The highest incidence of antibiotic resistance in E. coli was against cefotaxime and colistin (100%). A significant difference in the prevalence of CTX-M-group 1 gene was observed among E. coli isolates in water samples (p < 0.05). The results indicate a high prevalence of beta-lactamase harboring E. coli in the mangrove ecosystems that can hamper mangrove-dependent aquaculture practices and human health.