Phenotypic characteristics of Streptococcus iniae and Streptococcus parauberis isolated from olive flounder (Paralichthys olivaceus).
The etiological agents of streptococcosis were isolated from diseased olive flounder collected on the Jeju island of Korea. A total of 151 bacterial isolates were collected between 2003 and 2006. The isolates were examined using various phenotypic and proteomic analyses, including sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, and glycoprotein assays. In addition, isolates were grown on blood agar to assess hemolytic activity, and biochemical assays were performed using the API20 Strep kit. Our results revealed that all isolates were nonmotile, Gram-positive cocci that displayed negative catalase and oxidase activities. Multiplex PCR assays revealed that 43% and 57% of the isolates were Streptococcus iniae and Streptococcus parauberis, respectively. These results were consistent with those of the SDS-PAGE and immunoblot analyses using whole-cell lysates of bacterial isolates. Significant differences were observed with respect to the Voges-Proskauer, pyrrodonyl arylamidase, alkaline phosphatase, and hemolytic activities of the S. iniae and S. parauberis isolates. Isolates of S. iniae displayed uniform profiles in the immunoblot and glycoprotein assays; however, immunoblot assays of S. parauberis isolates (using a chicken IgY antibody raised against a homologous isolate) revealed three distinct antigenic profiles. Our findings suggest that S. parauberis and S. iniae are endemic pathogens responsible for the development of streptococcosis in olive flounder.
Nho
Seong-Won
SW
Laboratory of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary medicine, Gyeongsang National University, Jinju, Gyeongnam, Korea.
Shin
Gee-Wook
GW
Park
Seong-Bin
SB
Jang
Ho-Bin
HB
Cha
In-Seok
IS
Ha
Mi-Ae
MA
Kim
Young-Rim
YR
Park
Yon-Kyoung
YK
Dalvi
Rishikesh S
RS
Kang
Bong-Jo
BJ
Joh
Seong-Joon
SJ
Jung
Tae-Sung
TS
D000818:Animals; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005393:Fish Diseases / Q000382:microbiology*; D005432:Flounder / Q000382:microbiology*; D015151:Immunoblotting; D007723:Korea; D010641:Phenotype; D016133:Polymerase Chain Reaction; D040901:Proteomics; D013290:Streptococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013291:Streptococcus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification
D004269:DNA, Bacterial