Staphylococcus aureus adheres to human intestinal mucus but can be displaced by certain lactic acid bacteria

Abstract

There is increasing evidence thatStaphylococcus aureusmay colonize the intestinal tract, especially among hospitalized patients. AsStaph. aureushas been found to be associated with certain gastrointestinal diseases, it has become important to study whether this bacterium can colonize the intestinal tract and if so, whether it is possible to prevent colonization. Adhesion is the first step in colonization; this study shows thatStaph. aureusadheres to mucus from resected human intestinal tissue. Certain lactic acid bacteria (LAB), mainly commercial probiotics, were able to reduce adhesion and viability of adherentStaph. aureus. In displacement assays the amount of adherentStaph. aureusin human intestinal mucus was reduced 39–44 % byLactobacillus rhamnosusGG,Lactococcus lactissubsp.lactisandPropionibacterium freudenreichiisubsp.shermanii. Moreover, adherentLactobacillus reuteri,Lc. lactisandP. freudenreichiireduced viability of adherentStaph. aureusby 27–36 %, depending on the strain, after 2 h incubation. This was probably due to the production of organic acids and hydrogen peroxide and possibly in the case ofL. reuterito the production of reuterin. This study shows for the first time thatStaph. aureuscan adhere to human intestinal mucus and adherent bacteria can be displaced and killed by certain LAB strains viain situproduction of antimicrobial substances.