The impact of chronic pseudomonal infection on pulmonary function testing in individuals with cystic fibrosis in Pretoria, South Africa

BACKGROUND: Colonisation of the airway by Pseudomonas spp. in cystic fibrosis has been reported to be an important determinant of decline in pulmonary function. OBJECTIVE: To assess pulmonary function decline and the presence of bacterial colonisation in patients with cystic fibrosis (CF) attending a CF clinic in a developing country. METHODS: A retrospective audit of patients attending the CF clinic at Steve Biko Academic Hospital, Pretoria, South Africa, was performed. The data included spirometric indices and organisms routinely cultured from airway secretions (Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA)). RESULTS: There were 29 study subjects. Analysis of variance for ranks (after determining that baseline pulmonary function, age, gender and period of follow-up were not contributing to pulmonary function decline) revealed a median decline in forced expiratory volume in 1 second, forced vital capacity and forced expiratory flow over 25 - 75% expiration of 12%, 6% and 3%, respectively, for individuals colonised by PA. There was no pulmonary function decline in individuals not colonised by PA, or in individuals colonised by SA. CONCLUSION: Pulmonary function decline in this South African centre is significantly influenced by chronic pseudomonal infection. Other influences on this phenomenon should be explored.