2021~2026년 기간 제주 양식 넙치(Paralichthys olivaceus)에서 분리되는 Streptococcus parauberis의 혈청형 변화 분석 = Serotype dynamics of Streptococcus parauberis isolated from cultured olive flounder (Paralichthys olivaceus) in Jeju, 2021~2026

다국어 초록 (Multilingual Abstract)

Among the bacterial pathogens of cultured olive flounder (Paralichthys olivaceus) on Jeju Island, the leading flounder-producing region of South Korea, streptococcosis continues to cause substantial mortality and economic losses. The long-term serotype dynamics of Streptococcus parauberis in Jeju have been previously characterized for the period 2003~2020, and a subsequent report described the serotype composition and antimicrobial resistance gene carriage of 296 S. parauberis isolates collected from Jeju between 2019 and 2022; however, year-by-year monitoring data covering the most recent period have not been reported. In this study, Gram-positive cocci isolated from diseased olive flounder collected on Jeju Island between 2021 and April 2026 were identified to species level by multiplex PCR, and S. parauberis isolates were further serotyped using the multiplex PCR primers for subserotype Ia, Ib/Ic, and serotype II along with the SP3-130F/R primer pair for serotype III. A total of 129 streptococcal isolates were recovered, all of which were assigned to S. parauberis (100.0%, 129/129); neither S. iniae nor Lactococcus garvieae was isolated throughout the surveillance window. Among S. parauberis isolates, subserotype Ia was the dominant serotype (82.9%), followed by serotype II (12.4%) and Ib/Ic (4.7%); no serotype III isolate was recovered in any of the surveyed years. By extending the previously published 2003~2020 monitoring, this study provides a comprehensive year-by-year description of the serotype dynamics of S. parauberis in Jeju olive flounder farms over a continuous 24-year period (2003~2026).