Influence of breastmilk on the development of resistance to intestinal colonization in infants born at the Atma Jaya Hospital, Jakarta.
A study of intestinal colonization resistance (CR) in breastfed versus formula-fed newborns at 4 intervals after birth in Jakarta, Indonesia, is described. To measure the intestinal CR for gram-negative enterobacilli, mean values of Enterobacteriaceae concentrations and mean numbers of Enterobacteriaceae biotypes were determined. The CR values found in this study show, that in all 4 sampling periods, at < 1, 2, 4 and 6 months, the mean concentration of Enterobacteriaceae was somewhat lower in the breastfed group than in the formula-fed group (only significant at 6 months). This means that the intestinal CR of the breastfed group may have been slightly higher than that in the formula-fed group. In both study groups, the CR was lower in the second and fourth month than soon after birth and at 6 months. For epidemiological reasons, comparison was performed of the Enterobacteriaceae biotypes found in samples from mother and child. The data show that, in the first sampling period, regardless of the theoretical possibility of a 'more intense (skin) contact' during breastfeeding (which might promote transfer of also microorganisms), the breastfed infants had a significantly lower percentage of identical Enterobacteriaceae biotypes than did the formula-fed group. This could possibly be ascribed to a higher CR in the breastfed group. Determination of the concentration of Enterococcus species was found applicable to reproducibly measure the CR in the newborns at 6 months and in the mother-group.