Impact of microbiology practice on cumulative prevalence of respiratory tract bacteria in patients with cystic fibrosis

Investigators participating in the Epidemiologic Study of Cystic Fibrosis p roject began to collect microbiological, pulmonary, and nutritional data on cystic fibrosis (CF) patients at 180 North American sites in 1994, Part of this study was a survey undertaken in August 1995 to determine microbiolog y laboratory practices,vith regard to pulmonary specimens from CF patients. The survey included a section on test ordering, completed by a site clinic ian, and a section on test performance and reporting, completed by each sit e's clinical microbiology laboratory staff. Seventy-nine percent of the sur veys were returned. There was intersite consistency of microbiology laborat ory practices in most cases. The majority of sites follow most of the CF Fo undation consensus conference recommendations. There were differences in th e frequency at which specimens for culture were obtained, in the use of sel ective media for Staphylococcus aureus and Haemophilus influenzae, and in t he use of a prolonged incubation for Burkholderia cepacia, These variations in practice contribute to prevalence differences among sites and may resul t in differences in clinical care.