Probiotic Activity ofEnterococcus faeciumandLactococcus lactisIsolated from Thai Fermented Sausages and Their Protective Effect AgainstClostridium difficile

Lactic acid bacteria,Enterococcus faeciumandLactococcus lactis, previously isolated from Thai fermented sausages were elucidated their probiotic properties especially in the control ofClostridium difficile630. Both isolates survived in simulated gastric solution at pH 3 followed in simulated intestinal solution at pH 8. The presence of skimmed milk also helped the bacteria to survive through acidic and alkaline in gastrointestinal conditions. The adhesion properties of both isolates were tested using a human colon adenocarcinoma cell line. The result showed that both isolates exhibited desirable probiotic properties which adhered to Caco-2 cells. The neutralized cell-free supernatant of both isolates demonstrated that no cytotoxicity toward Caco-2 cells vice versa cell-free supernatant ofC. difficile630 toward Caco-2 cell demonstrated high toxicity. The immunomodulation effect in response to bacterial neutralized cell-free supernatant and cell-free supernatant was also studied. The expression level of pro-inflammatory cytokine of Caco-2 cell which are tumor necrosis factor-alpha and interleukin-8 was evaluated using quantitative reverse transcriptase PCR. Both isolates were able to diminish the expression level of TNF-alpha and IL-8 induced by the cell-free supernatant ofC. difficile630. Hence, these isolates would be able to improve the gut health through counteracting theC. difficile-associated intestinal inflammation in human cell lines. These results may contribute to the development of the isolates using as probiotics.