Detection of Edwardsiella tarda by the specific amplification of a 450 bp fragment of 16S rRNA gene and its sequencing

Abstract

Edwardsiella tarda is agram-negative, motile,rod shaped bacterium, which causes low chronic mortality in farmed finfishes. In India, E. tarda infections occur frequently in fry, fingerlings and adults of many cultured species (Sahoo et al. 2000).E. tardawererecovered from muscle andkidney samples of live ulcerative Ophiocephalus punctatus and biochemically confmned (Kumar et al. 2006). Different serological tests, viz. indirect ELISA, competitive ELISA, dot blot ELISA and serum agglutination tests have beenused for rapid and confirmatory identification of E. tarda in infected and dead fish (Swain and Nayak 2003). The genetic relationship of E. tarda isolates from different habitats in India had been assessed by PCR-RFLP of 16S rDNA (Acharya et al. 2007). During recent years this approach has proven its usefulness for identification of bacterial isolates. The objectives of the study were to design, check the sensitivity and specificity of the polymerase chain reaction (PCR)primersbased on 16SrRNA gene sequence toE. Tarda for the rapid detection of the Indian isolates.