Epidemiological Study on Newly Emerging <i>Lactococcus garvieae</i> Serotype II Isolated from Marine Fish Species in Japan

Abstract

Lactococcus garvieae serotype II, a newly emerging causal pathogen of lactococcal infection, has spread to fish farms since 2012, and its damage to aquaculture has increased. A total of 161 strains were isolated from four fish species, yellowtail Seriola quinqueradiata, amberjack S. dumerili, kingfish S. lalandi, and striped jack Pseudocaranx dentex, in eight prefectures between 2012 and 2017. This is the first epidemiological study on L. garvieae serotype II, by using agglutination titers against antisera for diagnosis, biased sinusoidal field gel electrophoresis (BSFGE) analysis, and antimicrobial susceptibility test. Almost none of these strains were agglutinated with anti-Ia serum (anti-KG − serum), except for two strains agglutinated with both anti-Ia and II sera. BSFGE analysis revealed that genetically homogeneous L. garvieae serotype II has spread to fish farms since the first outbreak in 2012, and the strains resistant to lincomycin were already found in 2015.

Resistance and genomic characterization of a plasmid pkh2101 harbouring erm(B) isolated from emerging fish pathogen Lactococcus garvieae serotype II in Japan

“…A few studies have been conducted to determine the antibiotic resistance pattern of L. garvieae serotype II (Shi et al, 2019(Shi et al, , 2021.…”

“…Total genomic DNA was extracted from EM-resistant strains using a DNA extraction kit (Sigma Aldrich Co., LLC) according to the manufacturer's instructions. PCR amplification was performed to detect the presence of the erm (B) gene using a forward primer (3′-ATGAA CAA AAA TAT AAAATA-5′) and reverse primer (5′-TTATC TCC ATT CCC TTTAGT-3′) with an expected product size of 737 bp against the NCBI accession number MK784777.1 (Maki et al, 2008;Shi et al, 2019).…”

“…A previous study reported drug resistance of L. garvieae serotype II (Shi et al, 2019). Genomic analysis of the transfer of antibiotic resistance determinants from L. garvieae serotype II to other strains has not yet been performed.…”

Complete Genome Sequence of Lactococcus garvieae MS210922A, Isolated from Farmed Greater Amberjack (Seriola dumerili) in Japan

“…A vaccine containing formalin-inactivated cells dramatically ameliorated the damage caused by serotype I infection. Serotype II was identified in 2012 and has also caused economic losses ( 3 ). L. garvieae serotypes I and II can be differentiated using a slide agglutination test with rabbit antiserum and PCR-mediated identification methods ( 4 ).…”

Comparative genome analyses of three serotypes of Lactococcus bacteria isolated from diseased cultured striped jack (Pseudocaranx dentex)

“…Subsequently, L. garvieae serotype II infection has spread to many fish farms, causing severe losses. Since its first outbreak in 2012, serotype II infections have been known as a major problem in Japanese aquaculture (Shi et al, 2019). Recently, another new serotype of L. garvieae , isolated from greater amberjack ( Seriola dumerili ) in Japan has been reported.…”