Co-culture with potentially probiotic microorganisms antagonizes virulence factors of Clostridium difficile in vitro.

TREJO F. M., PÉREZ P. F. Y DE ANTONI G. L

ANTON LEEUW INT. J. G.

SPRINGER

Año: 2010 vol. 98 p. 19 - 29

0003-6072

Toxigenic strains of Clostridium difficile were co-cultured with different strains of bifidobacteria and lactobacilli. After centrifugation, spent culture supernatants were tested for biological activity on cultured Vero cells. Co-culture of Clostridium difficile with some potentially probiotic strains leads to diminution of the biological activity of spent culture supernatants. Observed effect cannot be ascribed neither to secreted factors from probiotics nor to toxin adsorption by bacterial cells. Immunological assays showed that there was significant diminution of both clostridial toxins (TcdA and TcdB) in spent culture supernatants of co-cultures as compared with pure clostridial cultures. Even though co-cultured clostridial cells showed a slight increase of intracellular toxins, this increase did not completely explains the diminution of toxin concentration in  culture supernatants. Evidence suggests that the antagonism could be due to the diminution of the synthesis/secretion of both clostridial toxins and it could be also related to a decrease  of  toxin release from the bacteria. Our findings provide new insight on the mechanisms involved in the protective effect of probiotics against Clostridium difficile.