Title: Stress responses in pathogenic Yersinia enterocolitica with reference to the stability of the virulence plasmid in food Authors
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: September 1, 2010
Publication Date: N/A
Technical Abstract: Yersinia enterocolitica has been associated with food-borne illness, most often due the ingestion of pork products. The pathogenic effects induced by a Y. enterocolitica infection are caused by the interplay of chromosomal genes and a virulence plasmid, pYV. Generally, the plasmid is lost during growth of the organism at greater than 32 C, resulting in avirulence. Prior exposure of Y. enterocolitica to sublethal temperatures (heat-shocking) leads to cells that are resistant to subsequent exposure at higher temperatures. Exposure of heat-shocked cells to 55C did not result in loss of pYV. There was no loss of pYV induced by freezing during storage, and freezing had no effect on enrichment and isolation of Y. enterocolitica. Growth of Y. enterocoliltica under vacuum or in atmospheres containing CO2 at 28C did not lead to plasmid loss. Y. enterocolitica can grow at pH values greater than or equal to 4.4, but the effect of acidification on the stability of the virulence plasmid is not known. Thus stressful conditions do not necessarily lead to the loss of pYV, and a food product containing the stressed pathogen may be capable of inducing food poisoning.