'Central Marine Fisheries Research Institute, Kochi'
Abstract
Vibrio parahaemolyticus is one of the most reported food-borne pathogen along the south-west coast of India, commonly
occurring in marine fish. For epidemiological purposes, this pathogen is confirmed by various molecular typing methods,
such as pulsed-field gel electrophoresis (PFGE) or ribotyping.These methods are labor intensive and time consuming. In the
present study, rapid typing methods with specific sequences viz., conserved ribosomal gene spacer sequence (RS), repetitive
extragenic palindromic sequence (REP), and enterobacterial repetitive intergenic consensus sequence (ERIC) and RAPD
(random amplified polymorphic DNA) were used. Marine fish / shellfish were collected from major landing centers located
along the south-west coast of India and screened for V. parahaemolyticus. Following phenotypic characterisation, fingerprinting
of bacterial strains was carried out by various typing methods viz., RAPD, ERIC, REP, and RS PCR. Cluster analyses
revealed the conglomeration of bacterial isolates into three and four groups using RAPD and RS respectively while it
revealed two major groups in each of the ERIC and REP PCR methods. ERIC-PCR method generated two major clusters,
one with the finfish and cephalopod isolates and the other with the strains isolated from shellfish samples suggesting that the
strains isolated from finfish samples showed higher genetic similarity with the strains from cephalopods than that of shellfish
isolates. However, RS PCR generated fewer amplified bands (eight) as compared to other typing methods, thus giving scope
for higher discrimination of various V. parahaemolyticus strains, suggesting it as a reliable practical method for routine use