The PTS Components in Affect Bacterial Capsular Polysaccharide Production and Macrophage Phagocytosis Resistance.

Capsular polysaccharide (CPS) is a crucial virulence factor for infection. We demonstrated an association of CPS production with two phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTSs). Deficiency of , encoding enzyme IIA of PTS, in enhanced the transcriptional activities of , and , which are in the gene cluster, leading to high CPS production. A mutant exhibited a higher survival rate in 1% hydrogen peroxide than the wild-type. The mutant showed less sensitivity to engulfment by macrophage (RAW 264.7) than the wild-type by observing the intracellular bacteria using confocal laser scanning microscopy (CLSM) and by calculating the colony-forming units (CFU) of intracellular bacteria. After long-term incubation, the survival rate of the intracellular mutant was higher than that of the wild-type. Deficiency of enhanced the transcriptional activities of which encodes another putative enzyme II complex of a PTS. Deletion of in the mutant reduced CPS production and the transcriptional activities of compared to those of the mutant. These results indicated that one PTS component, Crr, represses CPS production by repressing another PTS component, EtcABC, in . In addition, PTS plays a role in bacterial resistance to macrophage phagocytosis.