Molecular Characterization and Antimicrobial Resistance of E. coli Isolated from Fresh Water Market Fish

Escherichia coli are among the most widely prevalent organisms in the environment and have been isolated from many food animals. In this study a total of 134 market fish samples comprising 25 each of Catla, Rohu, Mrigal, Grass carp and Common Carp, and 9 Silver Carp were screened for the presence of E. coli. Among these samples, E. coli could be isolated and characterized biochemically as well as by PCR from 25 (18.66%) samples. Virulence genes detection by PCR study revealed the presence of stx1 and stx2 genes in 12% and 8% of isolates, respectively. Antimicrobial testing revealed the presence of multidrug resistant pathogenic E. coli. The presence of E. coli in market fish is considered a sanitary case and may represent a risk to the consumers. However, the presence of non-pathogenic E. coli in fish should be viewed as a public health concern since this bacterium is recognized as an indicator of fecal contamination. The present study supports the finding that fresh water fish can be regarded as critical source of pathogenic E. coli. This explains the need of strict monitoring and surveillance for effective measures of hygiene and sanitary practice during selling of fresh water fish.