Detection of Some Virulence Genes in Diarrheagenic Escherichia Coli Pathotypes in Children Under Five Years in Aleppo City

Abstract

Diarrheagenic Escherichia coli (DEC) strains can be classified into six main pathotypes based on their specific virulence properties. These pathotypes are associated with certain serotypes and exhibit distinct epidemiological and clinical features. The identification of DEC cannot be based solely on cultural and biochemical criteria, as they are indistinguishable from the non-pathogenic E. coli. However, the presence of virulence genes and DNA sequences specific to DEC can be used to determine its identity. The aim of this study is to investigate the prevalence of Diarrheagenic Escherichia coli (DEC) pathotypes among infected children under 5 years living in the city of Aleppo Syria. From June 2020 to September 2021, one hundred samples of diarrheal were collected from children under five years suffering from diarrhea admitted at Aleppo University Hospital and from some private laboratories in Aleppo city. Escherichia coli pathotypes were detected by using multiplex polymerase chain reaction and Phylogenetic genes were detected by Triplex PCR. The frequency of diarrheagenic E. coli was (48%), the most frequently isolated pathotypes were atypical enteropathogenic E. coli. (42%), followed by enterotoxigenic E. coli (4%), and enteroinvasive E. coli (2%). Enterohemorrhagic E. coli, enteroaggregative E. coli and Diffusely Adherent E. coli were not detected in any sample (0%). The most prevalent phylogenetic group of E. coli was "Phylogenetic group B2" which represented (62%), followed by "Phylogenetic group D" that comprised 33%, followed by "Phylogenetic group A" strains (3%). Strains of the "Phylogenetic group B1" were rare (2%). This study revealed that DEC strains contribute to cause diarrheal diseases in children, EPEC is the most commonly identified DEC strain. B2 and D groups are the most prevalent phylogenetic groups. In addition, they are virulent because these groups are associated with the presence of several virulence factors.