The study of the diversity of repeated sequences in E. coli strains isolated from Alborz province’s water sources

Abstract

Background and Aim: E.coli is a gram-negative bacillus from the family of Enterobacteriaceae. E. coli bacteria is used as a water indicator of urban sewage pollution. The repeating sequences, are replications of the genes or parts of them that are repeated. Tandem repeats may be available for the number of iterations in a different creature than other populations, which are called as consequent replications with variable numbers. The purpose of this study was to evaluate the diversity of repeated sequences of ms06 and ms23 loci in E. coli strains isolated from water resources in Alborz province. Materials and Methods: A total of 72 E.coli isolates which obtained from water sources in Alborz, Iran, from September 2012 to October in 2013, were analyzed, then standard and biochemical tests were used to identify and isolate E. coli bacteria, after that, DNA extraction was performed by boiling method. The diversity of repeated sequences of ms06 and ms23 loci in E. coli was conducted using polymerase chain reaction. Results: The current study showed that the locus ms06 had five different alleles (1 repeat, 2 repeat, 3 repeat, 4 repeat, 5 repeat) and locus ms23 showed four alleles (1 repeat, 2 repeat, 2.5 repeat). It is also founded that ms23 loci contain a null allele. Conclusions: This is the first study on the diversity of repeated sequences in E.coli strains isolated from water resources in Alborz. In this study, the variation of repeated sequences was high.

Keywords

• Escherichia coli
• Repeated sequences
• Polymerase Chain Reaction
• Alborz province