Staphylococcus aureus in patients with cystic fibrosis: an epidemiological analysis using a combination of traditional and molecular methods.

An epidemiological analysis of Staphylococcus aureus was conducted in a study group of 157 cystic fibrosis patients cultured over a 30-month period. The resulting S. aureus isolates were categorized by bacteriophage type, plasmid profile, and (in some instances) chromosomal restriction fragment pattern of the culture-positive patients with S. aureus (34 of 157) 44% only were sporadically infected while 68% shared identical strains with one or more other patients. Six patients exhibited persistent infection (for up to ten months) which, in three individuals, occurred as cycles of carriage and reappearance. By contributing toward our understanding of the persistence and spread of S. aureus in cystic fibrosis patients these data should aid in clarifying the role this organism may play in the course of the disease.