Background: Lactobacillus species can contribute positively to general and oral health and are frequently acquired\r\nby breastfeeding in infancy. The present study aimed to identify oral lactobacilli in breast and formula-fed 4 monthold\r\ninfants and to evaluate potential probiotic properties of the dominant Lactobacillus species detected. Saliva and\r\noral swab samples were collected from 133 infants who were enrolled in a longitudinal study (n=240) examining\r\nthe effect of a new infant formula on child growth and development. Saliva was cultured and Lactobacillus isolates\r\nwere identified from 16S rRNA gene sequences. Five L. gasseri isolates that differed in 16S rRNA sequence were\r\ntested for their ability to inhibit growth of selected oral bacteria and for adhesion to oral tissues. Oral swab samples\r\nwere analyzed by qPCR for Lactobacillus gasseri.\r\nResults: 43 (32.3%) infants were breastfed and 90 (67.7%) were formula-fed with either a standard formula (43 out\r\nof 90) or formula supplemented with a milk fat globule membrane (MFGM) fraction (47 out of 90). Lactobacilli were\r\ncultured from saliva of 34.1% breastfed infants, but only in 4.7% of the standard and 9.3% of the MFGM\r\nsupplemented formula-fed infants. L. gasseri was the most prevalent (88% of Lactobacillus positive infants) of six\r\nLactobacillus species detected. L. gasseri isolates inhibited Streptococcus mutans binding to saliva-coated\r\nhydroxyapatite, and inhibited growth of S. mutans, Streptococcus sobrinus, Actinomyces naeslundii, Actinomyces oris,\r\nCandida albicans and Fusobacterium nucleatum in a concentration dependent fashion. L. gasseri isolates bound to\r\nparotid and submandibular saliva, salivary gp340 and MUC7, and purified MFGM, and adhered to epithelial cells.\r\nL. gasseri was detected by qPCR in 29.7% of the oral swabs. Breastfed infants had significantly higher mean DNA\r\nlevels of L. gasseri (2.14 pg/uL) than infants fed the standard (0.363 pg/uL) or MFGM (0.697 pg/uL) formula.\r\nConclusions: Lactobacilli colonized the oral cavity of breastfed infants significantly more frequently than formulafed\r\ninfants. The dominant Lactobacillus was L. gasseri, which was detected at higher levels in breastfed than\r\nformula-fed infants and displayed probiotic traits in vitro.
Loading....