Reuterin and other anti-pathogenic

factors may be important for maintaining a healthy gut microbiota by preventing intestinal overgrowth by other commensal and pathogenic microorganisms. Recently, the addition of L. reuteri ATCC 55730 or reuterin to the intestinal microbiota was shown to reduce the E. coli population in an in vitro fermentation model [40]. Thus, antimicrobial compounds like reuterin may have a fundamental role in shaping and modeling the composition and spatial architecture of the gastrointestinal microbiota. L. reuteri biofilms produced reuterin, indicating that probiotic VE-822 mouse L. reuteri may be protective against Tideglusib price pathogens in either the planktonic or biofilm State. Interestingly, strains that produce relatively high

quantities of reuterin are immunostimulatory when cultured as planktonic cells. In vivo, immunostimulation by L. reuteri may promote colonization and biofilm formation of commensal lactobacilli, and reuterin could prevent opportunistic bacteria from establishing a niche. Hypothetically, once see more the immunostimulatory strains are established on the mucosal surface, TNF stimulation is diminished, and higher quantities of reuterin are produced. Elevated quantities of reuterin adjacent to the mucosa may effectively alter surrounding commensal microbial populations and prevent colonization and adherence by pathogenic bacteria. Biofilms are relatively resistant to several antimicrobial agents when compared to planktonic cultures [41]. The enhanced resistance of biofilms to antimicrobial compounds may explain, in part, the resistance of L. reuteri biofilms to reuterin and elevated amounts of reuterin produced by these biofilms, as described in this study. While the growth conditions used for the flow cell and planktonic cultures mafosfamide differed, similar probiotic activities by each L. reuteri strain were observed. TNF inhibitory activities and reuterin production of L. reuteri were also consistent when biofilms (in multiwell plates) and planktonic cells were cultured using the same growth

conditions. Although these experiments were conducted with biofilms grown in vitro on abiotic surfaces, biofilms with probiotic function may be important for delivery of beneficial effects in the mammalian host. A mutant strain of L. crispatus, unable to bind mucus and adhere to the colonic mucosa, did not have a protective effect in a murine colitis model compared to the wild type aggregating strain even when the bacteria were continuously supplied to mice [42]. Mucus-binding ability may be important for probiotics to adhere to the mucosal surface and form biofilms within the intestine. Defects in cell surface features may affect biofilm formation and the abilities of probiotics to persist and colonize the intestine in vivo. L.