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International Journal of Microbiology
Volume 2012, Article ID 728276, 7 pages
http://dx.doi.org/10.1155/2012/728276
Research Article

Comparative Genomic Analysis of Lactococcus garvieae Strains Isolated from Different Sources Reveals Candidate Virulence Genes

1Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
2Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
3School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5201, Japan

Received 6 October 2011; Revised 22 January 2012; Accepted 5 February 2012

Academic Editor: Arsenio M. Fialho

Copyright © 2012 Eiji Miyauchi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Lactococcus garvieae is a major pathogen for fish. Two complete (ATCC 49156 and Lg2) and three draft (UNIUD074, 8831, and 21881) genome sequences of L. garvieae have recently been released. We here present the results of a comparative genomic analysis of these fish and human isolates of L. garvieae. The pangenome comprised 1,542 core and 1,378 dispensable genes. The sequenced L. garvieae strains shared most of the possible virulence genes, but the capsule gene cluster was found only in fish-pathogenic strain Lg2. The absence of the capsule gene cluster in other nonpathogenic strains isolated from mastitis and vegetable was also confirmed by PCR. The fish and human isolates of L. garvieae contained the specific two and four adhesin genes, respectively, indicating that these adhesion proteins may be involved in the host specificity differences of L. garvieae. The discoveries revealed by the pangenomic analysis may provide significant insights into the biology of L. garvieae.