[Microbiological parameters of clinical interest in pulmonary infection in cystic fibrosis]

A 5-year study in patients with cystic fibrosis was carried out in order to gain a better understanding of the microbiological factors influencing clinical status and evolution.

Fifty-two patients were evaluated (mean age 16.6 years, range 0-36) during a 5 years-period (July 1988- July 1992). The clinical score of Shwachman and pulmonary function were evaluated at the beginning and at the end of the study period. Quantitative bacterial cultures were performed every 3 weeks recording the different colonical morphotypes of Pseudomonas aeruginosa.

Beside the expected results regarding the prevalence of P. aeruginosa (80.7%) and Staphylococcus aureus (65.5%), a low rate of chronic infection with Burkholderia cepacia (1.9%) and high with S. maltophilia (9.6%) was found and it is worth noting the presence of Salmonella spp. in 3 patients. Microbial colonization followed the classical age-related sequence with 53.8% of patients older than 10 colonized with mucoid strains of P. aeruginosa. Colonization with mucoid Pseudomonas, increase in sputum bacterial counts and high diversity in colonizing morphotypes were parameters related with reduced clinical scores.

The sequential study of the bacterial colonization in cystic fibrosis is important to follow the prognosis and evolution of the disease, and therefore, to choose the most effective therapy.