Molecular Identification of the colicin types in Escherichia coli in the Yasuj city

colicins are a group of bacteriocins produce by Escherichia coli and act against pathogenic bacteria Escherichia coli. Today, the use of colicinogenic strains as probiotic microorganisms and replace them instead of the combination of antibiotics are taken into consideration. Therefore, this study was conducted to identify the different types of colicins in commensal Escherichia coli. This research was a descriptive - analytic study was performed on 120 stool samples that randomly was isolated from the commensal Escherichia coli in children referred to health centers in the Yasuj city. Firstly, E. coli isolates were determined by common biochemical tests. Then colicin gene existence was analyzed using specific primers 9. Data were analyzed by chi-square test. Of the 120 commensal E. coli in 85 cases (71%) colicin gene has been identified, so that 34/11% of samples containing a gene, 45/89% contain two genes and 20% of the samples had more than two genes. A strain was observed with six different colicin. The highest and lowest frequencies were related to colicin-coding genes IaIb and ANS4. the strains with more than one colicin gene showed a high frequency. These strains have a selective advantage for inhibition sensitive strains. The presence of colicin in the gastrointestinal tract, an important factor is to inhibit other pathogenic Escherichia coli.