Molecular phylogeny of Escherichia coli isolated from clinical samples in Hilla, Iraq

Abstract

Escherichia coli strains can be assigned to one of the main phylogenetic groups (A, B1, B2 and D). Strains of these groups differ in their phenotypic characteristics, including the ability to use certain sugars, antibiotic resistance profiles and growth rate-temperature relationships. A total of 45 E. coli isolates were obtained from different clinical samples by standard bacteriological methods. PCR was conducted to determine the phylogenetic grouping of these isolates by targeting two genes, chuA, yjaA and anonymous DNA fragment TspE4.C2. Three phylogeny genetic markers (chuA, yjaA and TspE4.C2) were used. Results found that the most isolates of E. coli belong to the phylogeny group A (44.4%) which includes: urine (3 samples), stool (8 samples), rectal (6 samples), and vagina (3 samples), followed by group B1 (22.2%) which included urine (4 samples), stool (2 samples), rectal (3 samples) and vagina (1 samples), group B2 (17.7%) which included urine (5 samples), and vagina (3 samples), while group D (15.5%) which included urine (3 samples), rectal (1 sample) and 3 vagina samples. Phylogeny pedigree was done according to the data recovered previously. This study explains that the distributions of E. coli isolates in phylogenetic groups (A, B1, B2 and D) varied depending on the characteristics of host population and also on the variation in bacterial sources.

Key words: Phylogeny, Escherichia coli, polymerase chain reaction.