Identification and Characterization of Enteropathogenic Escherichia Coli (EPEC) Variant and Screening of Their Antigenic Proteins

Abstract

Diarrhoea is the second most common cause of deaths in young children. Escherichia coli and its different pathotypes are generally associated as one of the major etiologic factors. Enteropathogenic E.coli (EPEC) pathotype have been explored extensively as major contributor among all pathotypes of diarrhoeagenic Escherichia coli. However, novel and unusual strains of EPEC have also been reported by several groups. One of the unusual patterns producing EPEC is Escherichia albertii which shows the new emergence, associated with gastrointestinal disorders in various parts of world. In the present study an attempt was made to answer the questions that arose during the analysis of Next Generation Sequencing (MiSeq). 16sRNA genes analysis through MiSeq from diarrhoea stool samples of paediatric patients revealed the presence of E.albertii in our region. Therefore, EPEC strains of diarrhoeagenic Escherichia coli were further taken forward for the biochemical and molecular characterization. 45 EPEC strains (eae gene +ve) were targeted by multiplex PCR for lysp (lysine-specific permease) and mdh (malate dehydrogenase) genes. Among them, total 11 strains were positive and marked the presence of lysp and mdh along with eae gene confirming these as EPEC-variant strains. Their biochemical and molecular profiles were similar as with the reported Escherichia albertii profile. The lysp and mdh amplified genes also confirmed by Sanger sequencing and results overlapped with the genome of Escherichia coli. SDS-PAGE technique was done to observe comparative membrane proteins profiling of pathogenic and non-pathogenic strains so that the novel membrane proteins may be further processed as antigenic proteins. SDS-PAGE profile revealed the differences in the banding patterns of pathogenic (EPEC and EPEC-variant) and non-pathogenic (E.coli- DH5α) Escherichia coli. Remarkable biochemical, molecular and proteomic assets were observed in these atypical EPEC strains which correspond to mysterious clades in phylogeny of Escherichia genus, which further needs to be explored.