Few studies, however, have examined lactobacilli in infants and probiotic activity of strains. Breast milk provides nutrition for the infant, bacteria that can impact the microbial composition of the gastro-intestinal tract [15, 16], and components that can influence bacterial attachment and growth in the mouth, stomach and intestine [17–19]. The dominant constituents in milk
are lipids, lactose, oligosaccharides and proteins [20], and the major energy source in milk is triglycerides and other fats. Fats are extruded from the epithelial cell as globules that are enveloped by the epithelial cell membrane, known as the “milk fat globule membrane” (MFGM) [21]. MFGM is rich HDAC phosphorylation in phospholipids, gangliosides, cholesterol and many biologically active proteins [21]. The MFGM fraction participates in cellular processes and defense
mechanisms in the newborn, including those involved in microbial acquisition [22, 23]. MFGM proteins comprise 1-4% of the total milk protein [22], and includes seven major protein components: alpha-lactalbumin, lysozyme precursor, beta-casein, clusterin, lactotransferrin, polymeric immunoglobulin HSP990 cost receptor precursor, and human milk fat globule EGF-factor 8 protein [23, 24]. Many of these proteins are glycosylated [23]. MFGM adheres to Lactobacillus reuteri[25], but does not affect L. acidophilus or L. gasseri[26]. The aim of the present study was (i) to quantitate total lactobacilli in saliva from 4 month-old breastfed and formula-fed infants, (ii) to identify the
dominant Lactobacillus species and (iii) evaluate possible probiotic traits of the most prevalent Lactobacillus species by analyzing NU7026 molecular weight their adhesion to host exocrine secretions and tissues Tenoxicam (saliva, milk, purified human MFGM fraction, and epithelial cells), and their effect on growth of selected oral species in vitro. Here we report that oral lactobacilli are detected more frequently in breastfed than formula-fed infants, and that L. gasseri, the dominant species detected, has probiotic traits. Methods Study group Four month-old infants were recruited from an ongoing study evaluating a novel infant formula (NCT00624689, total n=240, PI M. Domellöf, Umeå University, Sweden). Details of the parent study will be reported elsewhere (unpublished data, Timby N, Hernell O, Lönnerdal B, Domellöf M). Infants entering the parent study between September 2009 and June 2012 were invited to participate in the current study that added oral microbial sampling (saliva and oral mucosal swabs). Inclusion criteria were: 0–2 months old, birth weight 2,500-4,500 g, full term, and exclusively breast or formula-fed at the time of recruitment. The exclusion criterion was chronic illness. The parent study population aimed to recruit twice as many formula- as breastfed infants. Formula-fed infants received either a standard infant formula (Semper AB, Sundbyberg, Sweden) or an infant formula containing MFGM fraction (LACPRODAN® MFGM-10, Arla Foods Ingredients, Viby, Denmark).