Isolation And Characterization Of Bifidobacteria Populations In Infants In The Khomas Region, Namibia

ABSTRACT

Bacteria belonging to the genus bifidobacteria are reported to be the most abundant gut endosymbiotic flora in the intestinal tract of new-born infants, particularly those that have been exclusively breast-fed. This high concentration of this gram-positive anaerobic bacteria has been attributed to the prebiotic and bifidogenic factors present in human breast milk. Currently, there is limited information on the presence of bifidobacteri aspecies in Namibia. The aims of this study were to identify and characterize bifidobacteria, to profile their antimicrobial activity, test few of their probiotic characteristics such as bile, lysozyme, acid and H2O2 tolerance capabilities and to assess their diversity in infant faeces detected by genus specific PCR and presence of the caseinolytic protease C (ClpC) gene.A total of 25 faecal samples collected from Khomas region showed total plate counts ranging from 32.00 × 105 to 204 × 107 colony forming units (CFU)/mL, with mean bifidobacteria plate count ranging from 1.4 × 104 CFU/mL to 3.6 × 108 CFU/mL. Bifidobacteria genus was confirmed by F6PPk assay further identified by 16S rDNA sequencing. Fourteen (14) of the 25bifidobacterial isolates demonstrated the ability to withstand the antimicrobial effects of extremes pH (pH 3.2 and 9.2), with 52 % isolates demonstrating the ability to grow at 0.7% bile concentration. Furthermore, fourteen isolates demonstrated ability to withstand the inhibitory effects of lysozyme and H2O2. These isolates demonstrated antagonistic activity against indicator strains.