Phylogenetic group distribution and antibiotic resistance of Escherichia coli isolates in aquatic environments of a highly populated area

Extended-spectrum beta-lactamase (ESBL)-producing including ( ), are recognized as a global public health threat due to their multidrug-resistant (MDR) phenotypes and their rapid dissemination in aquatic environments. Nevertheless, studies investigating the prevalence and antimicrobial resistance (AMR) profile of ESBL-producing in Lebanese surface water are limited. This study aimed to assess the physicochemical properties and microbial contamination load and to determine the distribution of AMR patterns of ESBL-producing in surface water samples from different sites in the North Governorate of Lebanon. Water samples were collected from 25 major sites in North Lebanon. These samples were analyzed for the presence of total coliforms, , and fecal enterococci. Phenotypic and genetic characterizations were then performed for isolates to determine their resistance patterns and phylogenetic groups. Fifty-six samples out of 100 samples were positive for ESBL-producing , mostly harboring bla (40/56, 71%) including bla (33/40, 82%), bla gene (36/56, 64%), bla (20/56, 36%), and bla (16/56, 29%) including bla gene (11/16, 69%). Most ESBL-producing isolates belonged to the extra-intestinal pathogenic phylogroup B2 (40/56, 71.4%) while 10/56 (17.9%) belonged to the commensal phylogroup A. Our results highlight the need to implement effective water monitoring strategies to control transmission of ESBL-producing in surface water and thus reduce the burden on human and animal health.