ArticlesBackground: Specific probiotic bacteria have proven to be effective in the prevention and treatment of infectious diseases in early life in at-risk populations. The impact of administration of Bifidobacterium animalis subsp. lactis BB-12 (BB-12) on the risk of acute infectious diseases was studied in healthy children. Methods: In this double-blind, placebo-controlled study, 109 1-mo-old infants were assigned randomly to a probiotic group receiving a BB-12-containing tablet (n = 55) or a placebo (n = 54). Test tablets were administered to the infants twice a day (daily dose of BB-12 10 billion colony-forming units) until the age of 2 y with a novel slow-release pacifier or a spoon. Breastfeeding habits, pacifier use, dietary habits, medications, and all signs and symptoms of acute infections were registered in diaries by parents and in questionnaires by trained professionals. results: The infants receiving BB-12 were reported to have experienced fewer respiratory tract infections (RTIs; 87 vs. 100%; risk ratio: 0.87; 95% confidence interval: 0.76, 1.00; P = 0.033) than the controls. No significant differences between the groups were observed in reported gastrointestinal symptoms, otitis media, or fever. The baseline characteristics of the two groups were similar, as was the duration of breastfeeding. conclusion: Administration of BB-12 in early childhood may reduce RTIs.

The impact of controlled administration of Bifidobacterium animalis subsp. lactis BB-12 (BB-12) on the risk of acute infectious diseases was studied in healthy newborn infants. In this double-blind, placebo-controlled study, 109 newborn 1-month-old infants were assigned randomly to a probiotic group receiving a BB-12-containing tablet (n 55) or to a control group receiving a control tablet (n 54). Test tablets were administered to the infants twice a day (daily dose of BB-12 10 billion colony-forming units) from the age of 1 -2 months to 8 months with a novel slow-release pacifier or a spoon. Breastfeeding habits, pacifier use, dietary habits, medications and all signs and symptoms of acute infections were registered. At the age of 8 months, faecal samples were collected for BB-12 determination (quantitative PCR method). The baseline characteristics of the two groups were similar, as was the duration of exclusive breastfeeding. BB-12 was recovered (detection limit log 5) in the faeces of 62 % of the infants receiving the BB-12 tablet. The daily duration of pacifier sucking was not associated with the occurrence of acute otitis media. No significant differences between the groups were observed in reported gastrointestinal symptoms, otitis media or use of antibiotics. However, the infants receiving BB-12 were reported to have experienced fewer respiratory infections (65 v. 94 %; risk ratio 0·69; 95 % CI 0·53, 0·89; P¼ 0·014) than the control infants. Controlled administration of BB-12 in early childhood may reduce respiratory infections.

Probiotic bifidobacteria are widely used in the prevention of childhood diseases. These bacteria are also associated with caries occurrence. The present secondary analysis in a low-caries population evaluated the effect of early administration of Bifidobacterium animalis subsp. lactis BB-12 (BB-12) on caries occurrence and identified markers of dental decay in early childhood. In the original randomized, double-blind, placebo-controlled study (NCT00638677, http://www.clinicaltrials.gov), infants (n = 106) received BB-12, xylitol or sorbitol tablets from the age of 1-2 months to 2 years with a slow-release pacifier or a spoon (daily dose of BB-12 10¹⁰ colony-forming units, polyol 200-600 mg). The present data were collected using clinical examinations and questionnaires at the age of 4 years. The occurrence of dental caries was assessed using the International Caries Detection and Assessment System. Oral hygiene status and mutans streptococci (MS) levels were also determined. No differences were detected between the study groups in the occurrence of enamel caries (p = 0.268) or obvious dentinal caries (p = 0.201). The occurrence of caries was associated with daily consumption of sweet drinks (p = 0.028), visible plaque observed (p = 0.002) and MS detected in the dental plaque (p = 0.002). Administration of BB-12 in infancy does not seem to increase or decrease the occurrence of caries by 4 years of age in a low-caries population.

A randomized clinical trial studied the effects of early ad-ministration of Bifidobacterium animalis subsp. lactis BB-12 (BB-12) on oral colonization of (1) mutans streptococci (MS), and (2) BB-12. In this double-blind, placebo-controlled study, infants (n = 106) received probiotic bacteria (BB-12 group), xylitol (X group), or sorbitol (S group). Test tablets were administered twice a day (from the age of 1-2 months) with a novel slow-release pacifier or a spoon (daily dose of BB-12 10¹⁰ CFU, polyol 200-600 mg). Samples were collected from mucosa/teeth at the age of 8 months and 2 years for BB- 12 determination (qPCR) and plate culturing of MS (MSB, TYCSB), lactobacilli (Rogosa) and yeasts (Sabouraud). The MS levels of the mothers were determined (Dentocult SM Strip Mutans). The baseline characteristics of the three groups were similar. Mean duration of tablet delivery was 14.9 ± 6.7 months. In all groups, >90% of the mothers showed high MS counts (log CFU ≧5). MS colonization percentages of the children at the age of 2 years were rather low (BB-12 group: 6%; X group: 31%; S group: 10%; p < 0.05). The levels of lactobacilli and yeasts did not differ between the groups. BB-12 cell counts barely exceeding the detection limit were found in three of the oral samples of the 8-month-old children; however, the 2-year samples did not contain BB-12. The early administration of BB-12 did not result in permanent oral colonization of this probiotic or significantly affect MS colonization in the children.

No studies on the concentration dependency of the inhibition of Streptococcus mutans with xylitol are available. We studied xylitol-induced growth inhibition of two type strains, S. mutans NCTC 10449 and Ingbritt, and three clinical isolates of S. mutans. The strains were grown in Brain Hearth Infusion Medium in the presence of 0.001% (0.066 mM), 0.005% (0.33 mM), 0.01% (0.66 mM), 0.1% (6.6 mM), and 1% (66 mM) xylitol. Growth was followed by measuring the absorbance at a wavelength of 660 nm. The highest xylitol concentration tested in this study, 1%, showed mean inhibition percentages ranging from 61% to 76% when the growth inhibition of the five strains was compared to the control without xylitol at log-phase. For 0.1% xylitol, the inhibition percentages ranged from 22% to 59%. A concentration dependency was seen in the growth inhibition, with 0.01% xylitol being the lowest xylitol concentration inhibiting all five strains significantly (p < 0.001). The growth inhibition percentages determined for 0.01% xylitol, however, were low, and the inhibition was significantly weaker as compared to 0.1% and 1% xylitol. Our results suggest that low xylitol concentrations of 0.1% (6.6 mM) could inhibit mutans streptococci in vivo but even lower xylitol concentrations may be inhibitory.

Xylitol released from the food supplement, delivered with the novel pacifier, may result in salivary xylitol concentrations high enough to inhibit mutans streptococci in vivo.