Temperature Influences Phenotypic and Biofilm Changes in Mono- and Co-cultures of Streptococcus suis and Glaesserella parasuis
Streptococcus suis and Glaesserella parasuis are common commensals of the tonsils in healthy swine but can also be responsible for outbreaks of severe disease. The purpose of this study was to characterize phenotypic changes in S. suis and G. parasuis in mono- and co-culture in vitro. Planktonic and biofilm co-culture experiments indicated that the clinical S. suis serovar 9 had a fitness advantage over G. parasuis. It was also found that increased temperature could induce drastic changes in colony morphology and significant increases in biofilm biomass of all S. suis strains tested. It was also shown that extracellular matrix components were variable between S. suis strains. Our results suggest that S. suis may have morphological changes at increased temperatures that may promote polymicrobial interactions. Furthermore, clinical S. suis serovar 9 strains have unique biofilm characteristics that may be important for virulence potential that is not seen in serovar 2.