A Study of the Variation of E. coli Sequence Types Moderated by Bacteriophages in Environmental Sewage Samples from City of Islamabad

Abstract

E coli is one of the most variable organisms present in the environment as its genomic variations are numerous. Among many ways to study genomic variations, one is the method of sequence typing which can identify different types of an organism present in the environment. In this study, a total of 54 E. coli strains were isolated from sewage samples and identified and then sequenced by the two locus sequence typing method. Different frequencies offimH andfumC gene alleles were also indicated. These sequence types were associated with the antibiotic resistance gene, blacTx-M- 15 where 33.3% of the total population of the bacterial strains was positive for this antimicrobial resistant gene. Phage assay was done to check the effect of bacteriophages present in the sewage sample on the bacterial strains which showed the positive activity of phages from different sites against three bacterial strains. In summary, different sequence types of E. coli were found in the sewage samples and results suggest that the bacteriophages present in the enviro1U11ent may have a role to modulate the specific bacterial type in the environment.