Phylogenetic study, distribution of virulence genes and antibiotic resistance profiles of Escherichia coli isolated from Bushehr coastal water

Objective: Microbial pollution of coastal water continues to rise human health concerns, following the consecutive population growth, especially in urban communities along beaches. Bushehr coastal water was evaluated to understand the intensity of human health risks. In this study, E. coli strains isolated from Bushehr coastal water samples were characterized for their pathotypes, phylogenetic groups, and antibiotic resistance pattern. Methods: A total of 120 E. coli environmental isolates obtained from coastal water samples were analyzed for susceptibility to 22 different antibiotics by using the agar disc diffusion method. The polymerase chain reaction was performed to detect the distribution of virulence-associated genes and phylogenetic groups among selected isolates. Results: Among the isolates, the prevalence of multidrug resistance (MDR) and non- multidrug resistance (NonMDR) phenotypes were 60% and 34.17%, respectively. Moreover, the rate of resistance was highest to cotrimoxazole (24.17%) followed by ampicillin (22.50%) and nalidixic acid (18.33%). While the rate of resistance was lowest to cefepime, imipenem, and meropenem at the same rate of 0.83%. The pathogenic isolates contrived 10% of the population study and included EPEC, EIEC, and ETEC. The Clermont phylogenic analysis revealed phylogroup B1 (20.00%) was most prevalence followed A (19.17%), C (17.50%), E (13.33%), Clade I/II (3.33%), and B2 (2.50%). Moreover, 24.17% of isolates were not classified in the defined Clermont phylogroups. Conclusions: Any recreational use or food exploitation of the polluted areas of Bushehr beaches may cause transmission of multidrug-resistant and pathogenic E. coli strains to individuals and threaten human health.