EPIDEMIOLOGICAL MONITORING OF PSEUDOMONAS AERUGINOSA ISOLATES BY PULSED FIELD GEL ELECTROPHORESIS IN CYSTIC FIBROSIS PATIENTS

Bacterial infections are the principal cause of morbidity and mortality in cystic fibrosis (CF) patients. The main pathogen is Pseudomonas aeruginosa (Pa), which, after chronic colonization of the respiratory tract, causes progressive pulmonary damage. Chronic colonization by this pathogen is the most important unfavorable prognostic event for CF patients. Until now Burkholderia cepacia was considered the only Gram-negative bacterial strain responsible for epidemics in CF centers but the diffusion of Pa epidemic strains among patients has been recently described, with different degrees of virulence, transmissibility and antibiotic resistance. The epidemiology of bacterial pathogens is important in CF management and molecular techniques as pulsed field gel electrophoresis(PFGE)have recently been described for the genotyping of the isolated bacteria. The principal objectives of the present study are: * epidemiologic study of Pa isolates using PFGE, to evaluate the phenomenon of cross infection among patients and the presence of epidemic Pa clones; * study of genetic factors of the patient which may precondition him/her to the propensity of Pa colonization; * study of the efficacy of eradicating therapy for the first Pa colonization; * study of successive Pa colonizations to clarify whether the bacterial isolates are newly acquired strains or regrowth of strains which were not completely eradicated; * longitudinal study of Pa strains in chronically colonized patients by Pa to evaluate whether colonization is due to the presence of a single strain or multiple; The present study allows us: - to improve our knowledge of the biology of Pa colonizations - to furnish indications of the necessity of precise microbiological surveillance of CF patients - to assess the efficacy of eradication therapy for initial Pa colonization