Screening of colicin E1 and V genes in Escherichia coli strains isolated from diarrheic calves

Introduction and Objectives: Bacteriocins which are produced by a wide range of bacteria are proteinaceous compounds and can eliminate the some pathogenic microbes. Colicins are evaluated as important bacteriocins which one-third of Escherichia coli strains are able to produce at least one type of them. Diarrhea in calves is one of the most important diseases which a wide range of microorganisms can cause it. The aim of this study was to characterization of E. coli isolates possessing colE and colV genes from diarrheic calves in Jiroft, Iran. The results of87this study can help to our knowledge about microfloral population of the gastrointestinal tract in diarrheic calves to design better treatment and control strategies.Materials and Methods: Totally 90 E. coli isolates from diarrheic calves were obtained and were confirmed by biochemical methods including IMViC tests. DNA of the isolates was extracted by boiling method and PCR test was performed to detect colE1 and colV genes. Also to determine the phylogenetic groups, we used a multiplex PCR based method.Results: Amongst 90 E. coli isolates, 6 isolates (6.67%) had E1 and 10 isolates (11.11%) had V gene. Only one isolate had both E1 and V genes. Also 57 isolates (63.33%) were assigned into the phylogenic group A, 28 isolates (31.11%) in group B1, one isolate (1.11%) in group B2 and four isolates (4.44%) in group D. There was a specific relationship between the phylogenetic groups and E1 and/or V positive strains; 68.75% of the strains which possessed E1 and/or V genes belonged to phylogenetic group A and 31.25% belonged to phylogenetic group B1.Conclusion: In this study, frequency of colicinogenic strains, which are known as probiotic microorganisms, was low in diarrheic calves. Presence of colicin in the gastrointestinal tract may be an important factor for inhibition of other pathogenic strains which needs to more researches.

کلیدواژه ها:

Calves ، diarrhea ، Escherichia coli ، colicin ، phylogenetic