Genetic heterogeneity and functional properties of intestinal bifidobacteria

Abstract

Aims: The aim of the present study was to compare several molecular methods for the identification and genotyping of bifidobacteria, and further to investigate genetic heterogeneity and functional properties of bifidobacterial isolates from intestinal samples of Finnish adult subjects. Methods and Results: A total of 153 intestinal bifidobacterial isolates were included in initial screening and 34 isolates were further characterized. Identification results obtained with PCR-ELISA and ribotyping were well in accordance with each other, while randomly amplified polymorphic DNA (RAPD) gave tentative identification only to Bifidobacterium bifidum and to 65% of the B. longum isolates. The most commonly detected species were B. longum biotype longum followed by B. adolescentis and B. bifidum. In addition, B. animalis (lactis), B. angulatum and B. pseudocatenulatum were found. Ribotyping and pulsed-field gel electrophoresis (PFGE) proved to be discriminatory methods for bifidobacteria, but also RAPD revealed intraspecies heterogeneity. Besides two B. animalis (lactis) isolates with very close similarity to a commercially available probiotic strain, none of the intestinal isolates showed optimal survival in all tolerance (acid, bile and oxygen) or growth performance tests. Conclusions: Several species/strains of bifidobacteria simultaneously colonize the gastrointestinal tract of healthy Finnish adults and intestinal Bifidobacterium isolates were genetically heterogeneous. Functional properties of bifidobacteria were strain-dependent. Significance and Impact of the Study: Applicability of ribotyping with the automated RiboPrinter Ò System for identification and genotyping of bifidobacteria was shown in the present study.

Innate mechanisms for Bifidobacterium lactis to activate transient pro‐inflammatory host responses in intestinal epithelial cells after the colonization of germ‐free rats

“…[8][9][10] Clinical and animal studies provide evidence that certain strains of Bifidobacterium animalis (lactis), B. longum, B. infantis and B. breve may be effective in the prevention and/or treatment of gastroenteritis, necrotizing enterocolitis and chronic intestinal inflammation. 11,12 The molecular mechanisms underlying these protective effects of probiotic bifidobacteria in the gut are completely unknown.…”

Microbiota and Allergy: From Dysbiosis to Probiotics

“…The Th1 stimulation profile induced by B. adolescentis (Karlsson et al, 2004;He et al, 2002) may intensify pathology in allergic infants (He et al, 2002). However, the properties of intestinal bifidobacteria are highly strain-dependent (Matto et al, 2004), and this is particularly true of immunostimulatory properties (Menard et al, 2008;Medina et al, 2007). Bacteroidaceae are also associated with allergic development, although, as for clostridia and bifidobacteria, findings are contradictory.…”

Application of Several Molecular Techniques to Study Numerically PredominantBifidobacteriumspp. andBacteroidalesOrder Strains in the Feces of Healthy Children

“…In addition, this study confirms a previous report regarding unexpected presence of B. animalis strains in humans. 17) This non-native to human species is heavily used in industry, so these isolates probably originated from yogurt consumption.…”