Preterm infants are especially vulnerable to intestinal infections. Consequently, the establishment of a balanced microflora that may protect against infection is desirable in such infants. One external factor that is important for the quality of intestinal colonisation is the diet.
In a previous study on formula-fed preterm infants (Boehm et al. 2002), we were able to demonstrate that dietary OS (a mixture of 90% Galacto-oligosaccharides and 10% Fructo-oligosaccharides in a concentration of 1g/100ml) stimulate the growth of faecal bifidobacteria. In the present explorative analysis of this study, we focus on the effect of the dominance of bifidobacteria on the presence of clinically relevant pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Pseudomonas aeruginosa, Enterobacter, Klebsiella, Proteus, Streptococcus group B, Clostridium difficile, Bacillus subtilis and Acinetobacter).
The study involved 25 preterm infants with a maximum gestational age of 32 weeks.
All infants started with pasteurised breast milk. When the neonatologist decided to start formula feeding, the infants were randomised to one of two groups: preterm formula supplemented with 1g/100ml prebiotic OS (90% GOS, 10% FOS) or a non-prebiotic-containing preterm formula (control).
Faecal pathogens were recorded on days 1 and 28. The formulas were identical except for the addition of OS.
At the start of the study the sum of the studied pathogens was not significantly different between the two groups (log CFU/g stool: 7.34±0.62 vs 7.24±0.31; p=0.87). At the end of the study period the sum of the studied pathogens was significantly lower in the group fed the preterm formula supplemented with prebiotic OS compared to the control group (7.24±0.31 log CFU/g stool vs 7.67±0.58; p=0.039). When expressed as a percentage of total bacteria, the sum of the studied pathogens in the prebiotic group was also significantly lower than in the control group (0.52±0.66 vs 2.58±3.07%; p=0.011).
Boehm G et al. Arch Dis Child Fetal Neonatal Ed 2002;86:F176-F181.
The data demonstrate that stimulation of bifidobacteria by prebiotic OS reduces the presence of clinically relevant pathogens in the faecal flora, indicating that prebiotic substances might have the capacity to protect against enteral infections.