Emergence of Erythromycin-resistant <i>Lactococcus garvieae</i> Serotype III Carrying <i>erm</i>(B) Isolated from Striped Jack <i>Pseudocaranx dentex</i>

Lactococcus garvieae serotype III infections have been found in striped jack Pseudocaranx dentex since 2021. In the absence of a vaccine against serotype III, erythromycin (EM) is used to treat this infection. In 2024, five EM-resistant L.garvieae serotype III isolates were obtained from striped jack specimens. These isolates carried erm(B), an EM-resistance gene. The filter mating experiment confirmed that the EM-resistance trait was successfully transferred to L.formosensis as the recipient. All biased sinusoidal field gel electrophoresis (BSFGE) patterns of these strains were similar to the BSFGE type A of the previous study and coincided with each other.