Respiratory microbiology of patients with cystic fibrosis in the United States, 1995 to 2005.

Background: Numerous improvements in diagnostic and therapeutic strategies for patients with cystic fibrosis (CF) have occurred during the past 2 decades. We hypothesized that these changes could impact trends in respiratory microbiology.

Methods: Data from the Cystic Fibrosis Foundation Patient Registry were used to examine trends in the incidence and prevalence of bacterial pathogens isolated from patients with CF in the United States from 1995 to 2005.

Results: The number of patients with CF in the patient registry increased from 19,735 in 1995 to 23,347 in 2005. During the study period, the reported annual prevalence of Pseudomonas aeruginosa significantly declined from 60.4% in 1995 to 56.1% in 2005 (p < 0.001). The decline was most marked in children 6 to 10 years old (48.2 to 36.1%) and adolescents 11 to 17 years old (68.9 to 55.5%). Both the incidence (21.7% in 1995 and 33.2% in 2005) and prevalence (37.0% in 1995 and 52.4% in 2005) of methicillin-susceptible Staphylococcus aureus significantly increased and the age-specific prevalence was highest in patients 6 to 17 years old. The prevalence of methicillin-resistant S aureus increased from 0.1% in 1995 to 17.2% in 2005 and from 2002 to 2005 was highest in adolescents 11 to 17 years old. Both the prevalence and incidence of Burkholderia cepacia complex declined, while the prevalence of Haemophilus influenzae, Stenotrophomonas maltophilia, and Alcaligenes xylosoxidans increased.

Conclusions: Data from the patient registry suggest that the epidemiology of bacterial pathogens in patients with CF changed during the study period. Future studies should continue to monitor changing trends and define the association between these trends and care practices in CF.