Pathogenicity islands of Escherichia coli isolated from clinical samples

الملخص

Background:- Pathogenicity islands (PAI) are located on the chromosome; however, they can also be part of bacterial plasmid and phages . PAIs were first described in uropathogenic E. coli (UPEC). Gene encoding for hemolysin, P pili, S fimbriae have been found on
various PAIs in different E. coli strains of UTI . Objective:- The aim of this study to investigate the some of pathogenicity islands markers of E.coli isolated from clinical samples by using molecular primer. Patients and methods:- In a total, 12 E.coli strains were collected in this study. Strains were isolated from various clinical samples by standard bacteriological methods. PCR was conducted to determine the PAIs of the isolates by using primers papC, papG(I, II), sfa, hlyC/A , iucC and PAi. The PCR amplification product were visualized by electrophoresis on 1% agarose gels for 45min at 60v. the size of the
amplicons were determined by comparison to the 100 bp allelic ladder.
Results: In this study, 12 isolates of Escherichia coli were genotypically characterized by PCR assay. Among isolates studies it was found that PAi is found in only one isolates (urine). PapGI is absent from all isolates while papGII is present in ten isolates mostly in urine (n=3) and
vagina(n=3), papC is present in only one isolate include urine, sfa is present only in three isolates. Also, the gene hlyC/A is present in five isolates, mostly in urine(n=3), also, these positive isolates had the ability to produce extracellular hemolysin, and aerobactein gene iucC is present in eight isolates mostly in stool(n=3) and rectal(n=3).
Conclusion: Each steps in the infection process can be mediated by a number of alternative virulence factors and each strain may have a  unique combination of these factors.
Recommendation:- Direct molecular identification of E. coli in clinical samples.