BACTERIAL ATTACHMENT TO OROPHARYNGEAL EPITHELIAL-CELLS IN BREAST-FED NEWBORNS

On day 2 post partum, swab samples were obtained from the oropharyngx of 20 healthy, breast-fed babies. The samples were examined for aerobe s (culture on agar plates), for bacterial coating with the immunoglobu lins SIgA, IgG and IEM (immunofluorescence assay), for bacterial attac hment to epithelial cells (fluorescence microscopy of acridine orange stained material, and scanning electron microscopy). alpha-Hemolytic s treptococci grew almost exclusively in the oropharynx, while 32% (medi an value) of the epithelial cells showed bacterial attachment in abund ance, viz. > 50 attached bacteria per cell. 66% (median value) of the bacteria showed positive reactivity when treated with anti-human SIgA serum. 72% (median value) of the bacteria were coated with IgG, but no IgM coating of the bacteria could be detected. Newborns do not posses s IgA antibodies, as only IgG is able to pass the placental barrier. T he SIgA-rich colostrum is capable of coating the oropharyngeal bacteri a of breast-fed babies during their first days after birth. However, d espite abundant SIgA-coating, bacteria still succeed in attaching to t he epithelial cells of the oropharynx. This finding hints that factors other than SIgA impede the bacterial/cellular adhesion mechanism.