Evaluation of genetic diversity among aquatic and fecal isolates of Escherichia coli using multilocus variable number of tandem repeat analysis

Abstract

In developing countries like India, fecal pollution of surface waters is a major threat to public and environmental health. The aim of the study was to assess serological, phylogenetic and molecular diversity among aquatic Escherichia coli isolates from Yamuna river and their comparison with the animal fecal isolates. A total of 97 E. coli isolates from Yamuna river and domesticated animals were characterized by multilocus variable number tandem repeat analysis (MLVA) using four VNTR loci. The pathogenicity of these strains by serological and phylogenetic analysis was also determined. E. coli strains were differentiated into 53 distinct MLVA types with high discriminatory power, Simpson's index of 0.95 (95% CI 0.923-0.978). Cluster analysis and population modeling using minimum spanning tree suggested a possible epidemiological linkage among aquatic and fecal isolates. The study also reported the presence of highly diverse and pathogenic serotypes belonging to STEC and EPEC strains, particularly O157 and high prevalence of pathogenic phylogroups (phylogroup, B2 and D). The presence of such a high molecular heterogeneity among aquatic and fecal E. coli isolates emphasizes upon the need to develop proper fecal pollution abatement strategies for Indian natural bodies.

Genetic Characterization Among Carbapenem-resistant Escherichia coli Strains Using Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) Fingerprinting in South Africa

“…Studies by Yasir et al [74] and Sun et al [75] reported the genetic diversities in multidrug resistant ESBLproducing E. coli although, our study did not screen for ESBL in the E. coli strains nevertheless provides an opportunity for further analysis. EPEC strains were predominantly isolated from river water samples and our study corroborates with another report by Khare et al [76]. Our current study used ERIC-PCR to identify the various sources and this is supported by Ibekwe et al [77] who reported E. coli isolated from swine wastewater samples in the United States.…”