Inhibition effect of aerobic respiratory Lactococcus lactis on Salmonella enterica subsp. enterica serovar Typhimurium SL 1344 and its intestinal colonization ability

Lactococcus lactis undergoing aerobic respiration can consume oxygen and form an anaerobic environment. Salmonella, as a facultative anaerobic foodborne pathogen, multiply better under aerobic conditions. The purpose of this study was to explore aerobic respiration of Lactococcus lactis subsp. lactis (L. lactis) KLDS 4.0325 inhibitory effect on Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) SL 1344 in vitro and its colonization ability in vivo. Results indicate that L. lactis KLDS 4.0325 could inhibit the growth of S. Typhimurium SL1344 by producing bacteriocin. And L. lactis KLDS 4.0325 undergoing aerobic respiration could enhance this inhibitory effect, while reducing the expression levels of virulence genes sipB, sipC, and sopE2 in S. Typhimurium SL1344. L. lactis KLDS 4.0325 could be successfully labeled by CFDA-SE fluorescent probe, and the labeling rate was more than 97%. Murine experiments showed that L. lactis KLDS 4.0325 could adhere and colonize in the cecum and colon. Thus, L. lactis KLDS 4.0325 is a promising probiotic strain for the potential inhibition of Salmonella infection via its oxygen-scavenging in host gut.