Differences in survival, virulence and biofilm formation between sialidase-deficient and W83 wild-type Porphyromonas gingivalis strains under stressful environmental conditions.

Porphyromonas gingivalis is a major causative pathogen of chronic periodontitis. Within the inflammatory microenvironment, there exists extreme pH values, elevated temperatures and oxidative stress. Pathogens adapt to these stressful environmental conditions by regulating the transcription of virulence genes, modifying themselves with macromolecules and by aggregating and entering into a biofilm growth phase. Our previous study showed that the P. gingivalis sialidase can help cells obtain sialic acid from the environment, which is used to modify macromolecules on the surface of P. gingivalis cells. In this study, we compared the survival, virulence factors and biofilm formation of a sialidase-deficient strain (ΔPG0352) and the wild-type P. gingivalis W83 strain under various pH values, temperatures and oxidative stress conditions to identify the roles of sialidase in the adaptation of P. gingivalis to stressful conditions. Compared to the growth of the P. gingivalis W83 strain, the growth of the △PG0352 was more inhibited by oxidative stress (0.25 and 0.5 mM H Compared to the P. gingivalis W83 strain, the survival, virulence and biofilm formation of the ΔPG0352 were decreased under stressful environmental conditions.