The Frequency of PAI, aer and traT Genes in Escherichia coli Commensal and Urinary Pathogenic E. coli Isolates in Shahrekord and the Relationship Between the Two Groups by Multiplex PCR

Background: Nosocomial infections are acquired during hospital treatment or in a hospital environment. One such infecting agent is uropathogenic Escherichia coli and many virulence genes enable it to become pathogenic, thereby causing damage to the host. Objectives: This study aimed to identify aer, traT, and PAI genes in E. coli isolates collected from fecal and urinary tract infection (UTI) specimens and determine the relationship between them in both populations studied in a center in Iran by multiplex polymerase chain reaction (PCR) assay. Methods: Seventy-five isolates of E. coli from the urine of inpatients and 75 isolates from commensal fecal without UTI and diar-rhea were collected. The E. coli bacteria were detected and isolated, using biochemical techniques and supplementary tests in the Microbiology Laboratory of Shahrekord University of Medical Sciences. Antibiotic susceptibility pattern for14 antibiotics was done utilizing the disc diffusion method. The existence of aer, traT, and PAI virulence genes among all isolates was investigated by multiplex PCR. Results: Among the urinary pathogenic E. coli isolates, the highest antibiotic resistance was observed in cefazolin, ampicillin, and cotrimoxazole antibiotics. The prevalence rates of aer, traT, and PAI genes in the fecal isolates were 92%, 90.6%, and 46.6%, respectively. Further, their prevalence rates in urine isolates were 96%, 97.3%, and 41.3%, in that order. Conclusions: The presence of the high frequency of pathogenic islands (PAIs), especially in fecal samples, is important because these genes are easily transmitted and convert a commensal bacterium into a pathogen. Because only the genome of pathogenic bacteria has been unwrapped, little attention has been paid to PAIs in commensal bacteria.