Tetracycline resistance of Escherichia coli isolated from water, human stool, and fish gills from the Lake Sevan basin.

This article focuses on assessing the bacteriological water quality and tetracycline-resistant bacteria in the rivers of the Lake Sevan basin in Armenia, a critical freshwater resource for the South Caucasus. The study, conducted in autumn 2019 and spring 2020, found no significant differences in tetracycline resistance among Escherichia coli isolates from human gut microbiota, fish, and river water, with plasmid analysis suggesting possible horizontal gene transfer of resistance genes across these sources. Besides E. coli, other Enterobacteriaceae such as Edwardsiella, Morganella, and Proteus species were detected in the water, though coliform levels remained within standard limits. The findings underscore the importance of multidisciplinary investigations of microbial antibiotic resistance as an emerging indicator of water pollution, with implications for public health and environmental management in the Lake Sevan region.