关键词: 母乳, 双歧杆菌, 16S rRNA, 筛选与鉴定, 益生特性

Abstract: In this study, bifidobacterial strains isolated from the breast milk of Uygur women in Kashi, Xinjiang were identified at the species level and then their genetic variations were analyzed by using a combination of repetitive polymerase chain reaction (rep-PCR) fingerprinting and sequence analysis of the 16S rRNA gene. Meanwhile, routine physiological and biochemical parameters and phenotypic characteristics of sugar metabolism were examined, and the antibacterial activity of these isolates against 6 common pathogens and 3 conditional pathogens from breast milk was investigated along with their gastrointestinal tolerance. Our results showed that a total of 15 bifidobacterial strains including Bifidobacterium pseudocatenulatum (8 strains), B. breve (2 strains), B. longum subsp. longum (2 strains) and B. longum subsp. infantis (3 strains) were isolated from 15 breast milk samples. Among these strains, four B. pseudocatenulatum stains, namely MY92, MY75-1, MY72 and MY81, had a more potent and?broader-spectrum antibacterial activity, and strain MY92 showed the highest survival rate (20.37% and 0.302%) after challenge with simulated gastric and intestinal juices. Based on the above data, B. pseudocatenulatum MY92 is promising for application as a potent probiotic strain and shows great potential for the development of adjuvant preparations for preventing diarrhea in infants and young children.

Key words: breast milk, Bifidobacteria, 16S rRNA gene sequence, screening and identification, probiotic characteristics