Molecular Characterization of E. coli Isolated from Raw Vegetable

Abstract

Vegetables that are commonly consumed in raw form, collected from retail shops viz. coriander leaves, radish, green chilies, cucumber and tomato were tested for contamination with E. coli. Out of 80 samples processed, 43 (53.75) percent samples yielded E. coli. The highest prevalence of E . coli i.e. 86.66 percent was observed in coriander samples followed by 60.00 % in tomato, 53.33 % in reddish, 50.00 %in green chili and 20 % in cucumber samples. The isolates belonged to serogroups O4, O5, O11, O17, O20, O60, O63, O65, O69, O71, O116, O132, O138, O147, three rough strains and 10 untypable. The isolates were subjected to PCR for detection of mdh, elt, est, stx1 and stx2 genes. The mdh gene was amplified in all 43 isolates while elt gene was detected in 30 isolates belonging to six different serogroups viz. O17, O60, O69, O138 and O147 and 7 untypable E. coli. The est gene was exhibited by 20 isolates belonging to five different serogroups viz. O17, O 60, O69, O138 and 3 rough strain and 5 untypable isolates. Amplification of stx1 gene was detected in only two isolates, both of O65 serogroup whereas, stx2 gene was observed in 9 isolates belonging to serogroup O69 and 3 rough strains.