Effect of bacterial flora on staphylococcal colonisation of the newborn.

The umbilical and nasopharyngeal flora of newborn infants was examined on days 3, 14, and 42 of life. An analysis of the bacteriological findings suggests that colonisation by either Staphylococcus aureus or Staph. epidermidis prevents colonisation by the other staphylococcus. Similarly, colonisation by Gram-negative bacteria prevents colonisation by staphylococci. Further, this bacterial interference lasts for as long as 42 days, which suggests the possibility of artificially colonising newborns with nonpathogens to prevent subsequent colonisation and disease by virulent microorganisms.