Characterization and in vitro properties of oral lactobacilli in breastfed infants
Authors
Nelly Romani Vestman, Niklas Timby, Pernilla Lif Holgerson, Christine A Kressirer, Rolf Claesson, Magnus Domellöf, Carina Öhman, Anne CR Tanner, Olle Hernell and Ingegerd Johansson
Institution
Umea University
Country
Sweden
Year
2013
Journal
BMC Microbiology
Abstract
Background: Lactobacillus species can contribute positively to general and oral health and are frequently acquired
by breastfeeding in infancy. The present study aimed to identify oral lactobacilli in breast and formula-fed 4 monthold
infants and to evaluate potential probiotic properties of the dominant Lactobacillus species detected. Saliva and
oral swab samples were collected from 133 infants who were enrolled in a longitudinal study (n=240) examining
the effect of a new infant formula on child growth and development. Saliva was cultured and Lactobacillus isolates
were identified from 16S rRNA gene sequences. Five L. gasseri isolates that differed in 16S rRNA sequence were
tested for their ability to inhibit growth of selected oral bacteria and for adhesion to oral tissues. Oral swab samples
were analyzed by qPCR for Lactobacillus gasseri.
Results: 43 (32.3%) infants were breastfed and 90 (67.7%) were formula-fed with either a standard formula (43 out
of 90) or formula supplemented with a milk fat globule membrane (MFGM) fraction (47 out of 90). Lactobacilli were
cultured from saliva of 34.1% breastfed infants, but only in 4.7% of the standard and 9.3% of the MFGM
supplemented formula-fed infants. L. gasseri was the most prevalent (88% of Lactobacillus positive infants) of six
Lactobacillus species detected. L. gasseri isolates inhibited Streptococcus mutans binding to saliva-coated
hydroxyapatite, and inhibited growth of S. mutans, Streptococcus sobrinus, Actinomyces naeslundii, Actinomyces oris,
Candida albicans and Fusobacterium nucleatum in a concentration dependent fashion. L. gasseri isolates bound to
parotid and submandibular saliva, salivary gp340 and MUC7, and purified MFGM, and adhered to epithelial cells.
L. gasseri was detected by qPCR in 29.7% of the oral swabs. Breastfed infants had significantly higher mean DNA
levels of L. gasseri (2.14 pg/uL) than infants fed the standard (0.363 pg/uL) or MFGM (0.697 pg/uL) formula.
Conclusions: Lactobacilli colonized the oral cavity of breastfed infants significantly more frequently than formulafed
infants. The dominant Lactobacillus was L. gasseri, which was detected at higher levels in breastfed than
formula-fed infants and displayed probiotic traits in vitro.
Keywords: Lactobacillus, L.gasseri, Growth, Adhesion, Gp340, Breastfed infants