Journal of North Khorasan

Background and Objectives: Pathotypes of Escherichia coli, including EHEC (Enterohemorragic Escherichia coli) are an important cause of enteric disease and extra-intestinal. Shiga toxin E.coli (STEC), along with EHEC strains are known as the most common cause of diarrhea in developing countries. The purpose of this study was to evaluate the virulence genes in E.coli strain by Multiplex-PCR method isolated from diarrhea and determine antibiotic resistance.

Materials and Methods: In this cross-sectional study, after collecting 100 samples of human diarrhea of outpatient treatment centers in Tehran, culture and biochemical tests and 55 strains of Escherichia coli strains isolated and at the same time was extracted DNA. Antimicrobial susceptibility testing was performed by disk diffusion and E-test method based on CLSI guidelines with antibiotics from various groups. Statistical data were analyzed with SPSS version 19, using descriptive statistics.

Results: Most E.coli isolates resistant to antibiotics Erythromycin (100%) and Ampicillin (94%) and were sensitive to Nitrofurantoin (96%) Amikacin (100%). The test E-Test greatest Resistance to antibiotics erythromycin (100%) and the most sensitivity was observed to antibiotics Gentamycin and Amikacin (100%). According to the results of molecular analysis of 55 human samples, was identified in 12 samples (21/8%) Stx₂ gene and 4 sample (7/2%) Stx₁ gene.

Conclusion: The results obtained in this study compared to other studies showed that involved age, sample type, geographic location, type of diet, personal hygiene, seasons, identification and isolation procedures.

Keywords: Escherichia coli, STEC, virulence genes