مقالات پذیرفته شده در نهمین کنگره بین المللی زیست پزشکی
Frequency of Virulence Factors and stx1 and stx2 Genes in Fecal and Raw Food Isolates of Shigatoxigenic Escherichia coli
Frequency of Virulence Factors and stx1 and stx2 Genes in Fecal and Raw Food Isolates of Shigatoxigenic Escherichia coli
Fatemeh Bahrami Chegeni,1,*
1. Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
Introduction: Shiga toxin-producing bacteria are an important pathogen in foodborne diseases, and several foodborne outbreaks around the world have been linked to this bacterium.Infectious diarrheal diseases are a major problem and cause significant
mortality in the world. Escherichia coli, which produces Shiga toxin, is a pathotype of intestinal
Escherichia coli that causes diarrhea in humans. This pathotype can also cause hemolytic uremic
syndrome, especially in children. The present study was conducted to investigate the frequency of
contamination of raw foods with this bacterium and its role in the incidence of acute diarrhea in
society.
Methods: According to the results of our study, out of 80 samples of chicken meat 11%, out of
75samples of fresh vegetables 15% and out of 120 samples of human feces 5% of the samples
contained Shigatoxygenic Escherichia coli.Among chicken STEC samples 2% eae and 3% ExhA,
among STEC samples vegetables 4% eae and 3% ExhA and among STEC samples feces 1% eae
and 2.3% ExhA were identified. Among stool samples, the highest incidence of STEC was between
the ages of 12 and 25 years. In all samples, resistance above 85% to the antibiotic sulfamethoxazole
was observed and the lowest resistance to the boutique was meropenem. Among all STEC samples,
33% of the samples were AmpC and 11% of the ESBL samples.
Results: In this study, 75 fresh vegetable samples and 80 fresh chicken samples were collected from fruit and vegetable centers, and 120 stool samples from outpatients visiting medical centers were examined before taking any antibiotics.
Pre-enrichment and culture of the samples were performed according to ISO protocols, and the screened colonies were identified after DNA purification with a special kit for the identification of stx1, stx2, eae and ExhA genes. To determine antibiotic resistance by the disk diffusion method, all isolates were subjected to antibiogram testing.
Conclusion: The results of this study confirmed the presence of STEC strains in raw foods and their
role in the development of acute diarrhea. The presence of eaeandstx2 coding strains among these
isolates poses a risk of HUS among consumers. This study demonstrates the need for quality control
of raw food products for STEC contamination before distribution.