3/13/2016 yersinia enterocolitica yersinia enterocolitica virulence determinants virulence determinants Chromosomal virulence determinants Other virulence determinants Most strains secrete a heat-stable Iron overload in patients increases the risk for yersiniosis enterotoxin called yst -availability of iron in tissues Contribution of yst to diarrhea is Phospholipase A (yp/A)hydrolyzes unknown phospholipids in membranes and lyses red Ingestion of the preformed toxin in food blood cells is unlikely as the temperature required Urease increases acid tolerance to produce the toxin would result in -catalyzes release of ammonia from urea severe food spoilage contributes to survival in host tissues but the mechanism is unknown Yersinia enterocolitica virulence determinants Other virulence determinants ·pyV plasmid -highly invasive strains carry pyv -aids resistance to phagocytosis and lysis Type III secretion system -inject proteins into the host cytosol that aid pathogenicity 3/13/2016 9 Yersinia enterocolitica virulence determinants Chromosomal virulence determinants • Most strains secrete a heat-stable enterotoxin called Yst • Contribution of Yst to diarrhea is unknown • Ingestion of the preformed toxin in food is unlikely as the temperature required to produce the toxin would result in severe food spoilage Yersinia enterocolitica virulence determinants Other virulence determinants • Iron overload in patients increases the risk for yersiniosis - availability of iron in tissues • Phospholipase A (yplA) hydrolyzes phospholipids in membranes and lyses red blood cells • Urease increases acid tolerance - catalyzes release of ammonia from urea - contributes to survival in host tissues but the mechanism is unknown Yersinia enterocolitica virulence determinants Other virulence determinants • pYV plasmid - highly invasive strains carry pYV - aids resistance to phagocytosis and lysis • Type III secretion system - inject proteins into the host cytosol that aid pathogenicity