Bacteriocin Production by during Biofilm Development.

is a highly versatile bacterium ranging from commensal to intestinal pathogen, and is an important foodborne pathogen. species are able to prosper in multispecies biofilms and secrete bacteriocins that are only toxic to species/strains closely related to the producer strain. In this study, 20 distinct strains were characterized for several properties that confer competitive advantages against closer microorganisms by assessing the biofilm-forming capacity, the production of antimicrobial molecules, and the production of siderophores. Furthermore, primer sets for bacteriocins-colicins were designed and genes were amplified, allowing us to observe that colicins were widely distributed among the pathogenic strains. Their production in the planktonic phase or single-species biofilms was uncommon. Only two strains out of nine biofilm-forming were able to inhibit the growth of other strains. There is evidence of larger amounts of colicin being produced in the late stages of biofilm growth. The decrease in bacterial biomass after 12 h of incubation indicates active type I colicin production, whose release normally requires cell lysis. Almost all strains were siderophore-producing, which may be related to the resistance to colicin as these two molecules may use the same transporter system. Moreover, CECT 504 was able to coexist with in dual-species biofilms, but was selectively excluded, correlating with high expression levels of colicin (E, B, and M) genes observed by real-time PCR.