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Genotyping of S treptococcus dysgalactiae strains isolated from N ile tilapia, O reochromis niloticus ( L .)
Author(s) -
Costa F A A,
Leal C A G,
Leite R C,
Figueiredo H C P
Publication year - 2014
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/jfd.12125
Subject(s) - pulsed field gel electrophoresis , genotyping , streptococcus dysgalactiae , biology , typing , genotype , oreochromis , microbiology and biotechnology , outbreak , tilapia , genetic diversity , pathogen , population , virology , genetics , gene , fish <actinopterygii> , streptococcus , fishery , bacteria , streptococcus agalactiae , demography , sociology
Abstract Streptococcus dysgalactiae is an emerging fish pathogen that is responsible for outbreaks of disease on fish farms around the world. Recently, this bacterium was associated with an outbreak at a N ile tilapia, Oreochromis niloticus (L.), farm in Brazil. The aim of this study was to evaluate the genetic diversity, best genotyping method and aspects of molecular epidemiology of S . dysgalactiae infections in N ile tilapia farms in B razil. Twenty‐one isolates from four farms located in different B razilian states were characterized genetically using pulsed‐field gel electrophoresis ( PFGE ), ERIC ‐ PCR , REP ‐ PCR and sod A gene sequencing. The discriminatory power of the different typing methods was compared using Simpson's index of diversity. Identical sod A gene sequences were obtained from all isolates, and ERIC ‐ PCR and REP ‐ PCR were unable to discriminate among the isolates. PFGE typing detected three different genetic patterns between the 21 strains evaluated; thus, it was the best genotyping method for use with this pathogen. The strains from C eará S tate were genetically divergent from those from A lagoas S tate. The S . dysgalactiae isolates analysed in this study constituted a genetically diverse population with a clear association between geographical origin and genotype.