Occurrence of verotoxigenic E.coli in cow feces and antimicrobial resistance of the isolates in cattle farms in Shahrekord area

Escherichia coli is a common bacterium in the intestinal microflora of warm-blooded animals. They are routinely shed into the environment through feces and can contaminate water and soil, and, consequently fruits and vegetables .Enterohemorrhagic E. coli strains are recently emerged group of food-borne pathogens that are a significant public health threat. This group causes bloody diarrhea and hemolytic uremic syndrome (HUS), and the disease is prevalent in developed countries. The purpose of this study was to isolate and identify the E.coli O157: H7 and other verotoxigenic ones and major virulence genes (rfbE, eaeA, stx1, stx2) in fecal swab samples by PCR in Shahrekord area.
In Spring and Summer 2015, 400 cow fecal swab samples were collected from farms in Shahrekord area. Bacteriological and biochemical examinations were done for detection of E.coli. PCR assay was done for identification of O157:H7 serotype and other verotoxigenic E. coli using rfbE, eae, stx1 and stx2 genes.
E. coli O157:H7 was not detected in any strains tested. But PCR showed that out of 384 E.coli strain, 104(27/08%) isolates carried stx1 gene, 36(9/37%) carried stx2 gene and 16 (4.16%) carried both stx1 and stx2 genes. Intimin (eaeA) gene was detected in 280(72/91%) of the isolates. Among verotoxigenic strain antibiotic resistance to Tetracycline 87/1%, Ampiciline 51/62%, Cefotaxime 48/38%, Gentamycin 25/81%,, Ciprofeloxacin 3/22% and Sulfamethoxazol 3/22% were observed.
Discussion and According to the results, although the serotype O157: H7 did not isolate from the feces of cattle but other verotoxigenic strains that showed high resistance to antibiotic were isolated so it is a risk for human health.