Nasal staphylococci in children--a follow-up study.

Nasal carriage of Staphylococcus aureus was studied in a cohort of infants born to the residents of two towns in South Wales. The children were followed up to the ge of 5 years, nasal swabs being taken annually after a more detailed survey during the first year. The carriage-rate of S. aureus reached a minimum of 10-15% at one year and then rose steadily to 41% at five years. From the age of two years about 90% of the organisms isolated were resistant to penicillin. There was a marked tendency for children to carry the same strains from year to year, but carriage during the first year of life did not predict carriage at the age of five.