temperature effect on biofilm formation by lactococcus garvieae

Iran is one of the pioneers in raising rainbow trout and the current intensive farming conditions increases its sensitivity to various pathogens, which leads to significant losses. lactococcus garvieae is an emerging bacterial pathogen that causes lactococcosis, a septicemic disease that mainly affects rainbow trout in various parts of the world. the outbreak of this disease usually occurs in spring and summer, when the water temperature rises from 16 to 18 degrees celsius. the expression level of some lactococcus virulence genes increases at 37°c. biofilm formation is an ability that can promote persistent chronic infections by protecting bacteria from external damage and host immune responses. in addition, biofilm can play a role in bacterial pathogenesis by improving bacterial adhesion. the aim of this study was to investigate the biofilm formation ability of lactococcus garvieae isolates at different temperatures. for this purpose, a research was conducted using 30 lactococcus garvieae isolated from rainbow trout. polystyrene microtiter plates (96-well) were used to determine the ability of isolates to form biofilms at two different temperatures of 25 and 37°c. the results showed that there was a trend towards formation of more robust biofilm at 37°c among all the isolates. based on the results, temperature shifts can have dramatic impacts on biofilm formation and pathogenicity of lactococcus garvieae, which is important in making appropriate decisions regarding disease management and control.