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Phenotypic traits, virulence‐associated gene profile and genetic relatedness of E dwardsiella tarda isolates from J apanese eel A nguilla japonica in K orea
Author(s) -
Kim K.I.,
Kang J.Y.,
Park J.Y.,
Joh S.J.,
Lee H.S.,
Kwon Y.K.
Publication year - 2014
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12172
Subject(s) - edwardsiella tarda , biology , virulence , pulsed field gel electrophoresis , microbiology and biotechnology , japanese eel , intraspecific competition , 16s ribosomal rna , genotype , genetics , gene , japonica , zoology , botany
Edwardsiella tarda is the predominant bacterium in farm‐cultured eel in K orea. Here, we evaluated the heterogeneity of 37 E . tarda isolates derived from Japanese eel with various origins (olive flounder, common carp and ornamental fish) between 2003 and 2010. Regardless of origins, the biochemical characteristics of E . tarda isolates were homogenous except hydrogen sulfide production, citrate utilization and mannitol fermentation. Based on the phylogenetic analysis of 16S r RNA , E . tarda isolates could be classified into two subgroups and displayed a close relation with E dwardsiella ictaluri and E dwardsiella hosinae lineages, suggesting that the subgroup I has been a predominant type in the J eonnam and J eonbuk provinces. I ‐ C eu I‐based pulsed‐field gel electrophoresis ( PFGE ) typing showed that the isolates from J apanese eels belonged to 11 pulsotypes, indicating that the presence of highly genomic diversity. Additionally, two isolates, ET‐060 and ET ‐191, showed a high frequency of virulence genes (100%) and caused 90% and 60% mortality in Japanese eel, respectively. This finding suggests a substantial congruence of virulence gene profiles and pathogenicity. Our results demonstrate that the intraspecific diversity within E . tarda strains from Japanese eel has been in prior existence. Significance and Impact of the Study Based on the biochemical characteristics, the phylogenetic property of the 16S r RNA gene and PFGE types of E dwardsiella tarda , we could identify the intraspecific diversity of isolates from Japanese eel, A nguilla japonica in K orea. In addition, this study describes the strong congruence of virulence‐related genes and pathogenicity, suggesting that the virulence profile may be useful tool for prediction of pathogenicity.