<i>Bifidobacterium</i> <i>longum</i> subsp. <i>infantis</i> CECT7210 (<i>B. infantis</i> IM-1^®) Displays In Vitro Activity against Some Intestinal Pathogens

Abstract

Certain non-digestible oligosaccharides (NDO) are specifically fermented by bifidobacteria along the human gastrointestinal tract, selectively favoring their growth and the production of health-promoting metabolites. In the present study, the ability of the probiotic strain Bifidobacterium longum subsp. infantis CECT7210 (herein referred to as B. infantis IM-1®) to utilize a large range of oligosaccharides, or a mixture of oligosaccharides, was investigated. The strain was able to utilize all prebiotics screened. However, galactooligosaccharides (GOS), and GOS-containing mixtures, effectively increased its growth to a higher extent than the other prebiotics. The best synbiotic combination was used to examine the antimicrobial activity against Escherichia coli, Cronobacter sakazakii, Listeria monocytogenes and Clostridium difficile in co-culture experiments. C. difficile was inhibited by the synbiotic, but it failed to inhibit E. coli. Moreover, Cr. sakazakii growth decreased during co-culture with B. infantis IM-1®. Furthermore, adhesion experiments using the intestinal cell line HT29 showed that the strain IM-1® was able to displace some pathogens from the enterocyte layer, especially Cr. sakazakii and Salmonella enterica, and prevented the adhesion of Cr. sakazakii and Shigella sonnei. In conclusion, a new synbiotic (probiotic strain B. infantis IM-1® and GOS) appears to be a potential effective supplement for maintaining infant health. However, further studies are needed to go more deeply into the mechanisms that allow B.infantis IM-1® to compete with enteropathogens.

Keywords

• probiotics
• prebiotics
• synbiotic
• <i>Bifidobacterium longum</i>
• enteropathogens