The potential use of Enterococcus faecalis in the food industry is a controversial question because several strains belonging to this species may be potential dangerous for the human health. The interest of E. faecalis in fermented food industry depend on its lypolitic and proteolytic activities and on its ability to produce bacteriocins active towards bacterial food contaminants. On the contrary other strains of this same species are potentially pathogens being often involved in nosocomial infections. The extracellular proteomes of E. faecalis DISAV 1022 and E. faecalis H1,isolated from a Piedmont cheese and from an open surgical wound exudate, espectively, were analyzed. With this approach we would like to analyze differences among strains belonging to the same species but with different habitat origins. Supernatants of culture of both the strains were recovered in the exponential phase and proteins were precipitated with TCA. Proteomic analyses, performed by two-dimensional electrophoresis coupled with MALDI TOF/TOF mass spectrometry, highlighted the presence of proteins linked to pathogenicity only in E. faecalis H1: in particular this strain was able to produce an extracellular serine protease and the coccolysin which are among the main known virulence factors of this species. Furthermore i expresses also superoxide dismutase and some glycolytic enzymes probably present in extracellular broth as moonlighting proteins, potential virulence factors. On the contrary the food strain didn't produce potentially dangerous extracellular proteins but rather pheromones and other cross-comunication molecules. The expression of serine protease and coccolysin only in E. faecalis H1 were confirmed also by phenotypical assays. To understand if phenotypical differences depend on differential expression of virulence characters or to genetical acquisition of pathogenicity island, PCR analyses were performed: extracellular serine protease and superoxide dismutase genetical determinats revealed to be present in both the strains while coccolysin one was present only in E. faecalis H1.
Food starters: absence of virulence characters detected by extracellular proteomics
Lamberti C;
2010
Abstract
The potential use of Enterococcus faecalis in the food industry is a controversial question because several strains belonging to this species may be potential dangerous for the human health. The interest of E. faecalis in fermented food industry depend on its lypolitic and proteolytic activities and on its ability to produce bacteriocins active towards bacterial food contaminants. On the contrary other strains of this same species are potentially pathogens being often involved in nosocomial infections. The extracellular proteomes of E. faecalis DISAV 1022 and E. faecalis H1,isolated from a Piedmont cheese and from an open surgical wound exudate, espectively, were analyzed. With this approach we would like to analyze differences among strains belonging to the same species but with different habitat origins. Supernatants of culture of both the strains were recovered in the exponential phase and proteins were precipitated with TCA. Proteomic analyses, performed by two-dimensional electrophoresis coupled with MALDI TOF/TOF mass spectrometry, highlighted the presence of proteins linked to pathogenicity only in E. faecalis H1: in particular this strain was able to produce an extracellular serine protease and the coccolysin which are among the main known virulence factors of this species. Furthermore i expresses also superoxide dismutase and some glycolytic enzymes probably present in extracellular broth as moonlighting proteins, potential virulence factors. On the contrary the food strain didn't produce potentially dangerous extracellular proteins but rather pheromones and other cross-comunication molecules. The expression of serine protease and coccolysin only in E. faecalis H1 were confirmed also by phenotypical assays. To understand if phenotypical differences depend on differential expression of virulence characters or to genetical acquisition of pathogenicity island, PCR analyses were performed: extracellular serine protease and superoxide dismutase genetical determinats revealed to be present in both the strains while coccolysin one was present only in E. faecalis H1.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
