In order to identify the source of infection by Pseudomonas aeruginosa and Staphylococcus aureus in patients with cystic fibrosis (CF), systematic genotyping of isolates is necessary.
Multiple-locus variable-number tandem repeat analysis (MLVA / VNTR) is used to survey bacterial infection in all the patients of two paediatric CF centres in Paris. Patients, regularly followed up at the centres, provide sputum for bacterial culture. MLVA allows the identification of lineages composed of indistinguishable or closely related isolates. Our first results on P. aeruginosa show that common lineages are observed in several patients. One of them corresponds to “clone C” widely distributed in Europe. The study suggests that a limited number of pathogenic clones are responsible for chronic infection in CF patients. In addition it demonstrates that MLVA is an efficient, easy and rapid molecular method of epidemiological surveillance for bacterial infection. The longitudinal survey will be continued and the method will be now applied to the genotyping of S. aureus isolates from the same patients.
