RAPD-eaeA marker for detection of Enteropathogenic Escherichia coli from stool samples of north Indian patients

Enteropathogenic Escherichia coli (EPEC) are among the most important causes of acute enteritis and subsequent morbidity and mortality in children. This study aims to check the practicability of making use of Random Amplified Polymorphic DNA (RAPD) technique for the differentiation of various serotypes/ strains of EPEC by targeting eaeA gene. RAPD was used to fingerprint EPEC isolates and eaeA detection was done to confirm that the selected isolates harbored the "locus of enterocyte effacement" pathogenicity island. Using specific primers, we were able to get the band of 300-bp of eaeA gene coding for an outer membrane protein, intimin, and the presence of intimin among isolates was endorsed by immunoblotting. A consistent profile of RAPD was obtained with 90% polymorphism observed among the isolates. From this data, 6 unique strains of E. coli were identified and similarly, the constructed phylogenetic tree demonstrated the variation between the pathogenic and the non-pathogenic strains, suggesting genetic drift of these strains from each other. However, one pathogenic strain ZQA5 demonstrated close similarity with the non-pathogenic ZQA6 strain and suggesting the former to be a modem version of the ZQA6 by recently acquiring its virulent nature. Hence, it might be suggested that RAPD-eaeA marker can be utilized as a potential molecular tool for the identification of EPEC isolates.