Prognostic implications of initial oropharyngeal bacterial flora in patients with cystic fibrosis diagnosed before the age of two years.

To evaluate the significance of early bacteriologic findings in infants and younger children with cystic fibrosis, we divided patients identified at < or = 2 years of age into groups by initial oropharyngeal culture: group NF, normal respiratory flora (n = 17); group SA, Staphylococcus aureus without Pseudomonas aeruginosa (n = 20); group PA, P. aeruginosa without S. aureus (n = 6); group PA/SA, P. aeruginosa and S. aureus (n = 7); and group O, other potentially pathogenic bacteria (n = 31). Follow-up of patients ranged in age from 5.4 to 13 years. At diagnosis, group PA/SA had lower Brasfield scores (p < 0.02) and higher gamma-globulin levels (p < 0.03) than the other groups. Five years after diagnosis, Brasfield scores were significantly lower in groups PA and PA/SA compared with the other groups; mean gamma-globulin levels did not differ significantly among the groups. Groups PA and PA/SA also had evidence of significantly greater obstructive pulmonary disease by spirometry than groups NF and O. Group PA/SA had a 10-year survival estimate of 57%, significantly lower than the 92% to 100% estimates of the other four groups (p < 0.0001). Thus P. aeruginosa in initial oropharyngeal cultures from patients < or = 2 years of age with cystic fibrosis was associated with significantly increased morbidity, and the finding of P. aeruginosa and S. aureus together in initial oropharyngeal cultures with a significantly increased mortality rate during the first 10 years after diagnosis.