Characterization of potentially probiotic lactic acid bacteria and bifidobacteria isolated from human colostrum

摘要

Breast milk is the main source of nutrition for infants;it contains considerable microflora that can be transmittedto the infant endogenously or by breastfeeding,and it plays an important role in the maturation anddevelopment of the immune system. In this study, weisolated and identified lactic acid bacteria (LAB) fromhuman colostrum, and screened 2 strains with probioticpotential. The LAB isolated from 40 human colostrumsamples belonged to 5 genera: Lactobacillus, Bifidobacterium,Streptococcus, Enterococcus, and Staphylococcus.We also isolated Propionibacterium and Actinomyces.We identified a total of 197 strains of LAB derivedfrom human colostrum based on their morphology and16S rRNA sequence, among them 8 strains of Bifidobacteriumand 10 strains of Lactobacillus, including 3Bifidobacterium species and 4 Lactobacillus species.The physiological and biochemical characteristics ofstrains with good probiotic characteristics were evaluated.The tolerances of some of the Bifidobacterium andLactobacillus strains to gastrointestinal fluid and bilesalts were evaluated in vitro, using the probiotic strainsBifidobacterium lactis BB12 and Lactobacillus rhamnosusGG as controls. Among them, B. lactis Probio-M8and L. rhamnosus Probio-M9 showed survival rates of97.25 and 78.33% after digestion for 11 h in artificialgastrointestinal juice, and they exhibited growth delaysof 0.95 and 1.87 h, respectively, in 0.3% bile salts.These two strains have the potential for application asprobiotics and will facilitate functional studies of probioticsin breast milk and the development of humanmilk-derived probiotics.