Bacterial colonization of newborn infants and subsequent acquisition of hospital bacteria

Infants aged 3 to 24 hours were inoculated in the nose and throat with Staphylococcus epidermidis , or in the nose alone with diphtheroids or broth. Hospital acquisition of pneumococci or streptococci was similar in each group, but enteric bacilli were found less frequently in diphtheroid-colonized infants. This could not be attributed to bacterial interference, since it occurred in uncolonized throats as well as in colonized noses. Only one baby acquired S. aureus naturally. Some artificially colonized and uncolonized subjects were challenged intranasally with 10 1 or 10 2 S. aureus 502A at 27 to 48 hours; no protection against S. aureus was observed.