A survey of nasal Streptococcus pneumoniae in children.

Nasal swabs were taken from 369 four-year-old children in two South Wales towns and cultured for Streptococcus pneumoniae. The organism was isolated in 34% of the specimens, similar rates being found in boys and girls in the two towns. The children were swabbed again a year later, when the prevalence of nasal pneumococci had fallen to 25%. There was no association between the presence of the organism on the two occasions. Types 6 and 23 were most often isolated. After excluding children who had received an antibiotic, the proportion carrying a pneumococcus was higher in those who had recently had a respiratory infection than in the rest, although the difference was not quite statistically significant. There was a significant negative association between the presence of Staphylococcus aureus and Strep. pneumoniae.