Molecular surveillance and genetic diversity of Enterohemorrhagic Escherichia coli O157:H7 Pathotypes using MLVA method.

Abstract

BACKGROUND: Escherichia coli O157 is a major foodborne pathogen associated with severe human disease, with cattle serving as its primary reservoir, and in this study multilocus variable-number tandem-repeat analysis (MLVA) was applied to investigate the genetic diversity, distribution, and population structure of isolates collected in Fars Province, Iran. METHOD: This study was performed on 150 swab samples were collected from rectum and carcasses of cattle, sheep and goats and fruit juice in Fars province. Samples were processed following standard bacteriological procedures. MLVA method was performed based on polymerase chain reaction (PCR) by using four variable-number tandem repeat (VNTR). RESULTS: 22 isolates were identified as E. coli O157:H7 that 15, 6 and 1 were from cattle, sheep and fruit juice, respectively. By using MLVA technique, 22 isolates were separated into 15 distinct MLVA types. MST algorithm showed five genetically related clusters and by UPGMA method isolates were classified in 3 main cluster and 8 sub clusters. CONCLUSION: This study showed that MLVA can be used as a valid, inexpensive and rapid method to trace and analyze the phylogenetic relationships between E. coli strains in epidemiological research.