Epidemiology of Pseudomonas aeruginosa in cystic fibrosis and the possible role of contamination by dental equipment.

Cystic fibrosis (CF) patients often suffer from Pseudomonas aeruginosa lung infection yet the source of this organism is not known. In order to determine whether CF patients might be contaminated with P. aeruginosa from dental equipment, a total of 103 water samples from 25 dental sessions in Frederiksberg Municipal Oral Health Care Service were examined. Three samples (2.9%) were positive for P. aeruginosa. Three hundred and twenty-seven water samples from 82 dental sessions from various other Municipal Oral Health Services in Denmark, attended by CF patients, were also examined. Eighteen of 327 samples (5.5%) from nine sessions (11%) were positive for P. aeruginosa. In one case, genotypically identical (RFLP, pulsed-field gel electrophoresis) P. aeruginosa strains were found both in water from the dental equipment and in the CF patients sputum. This indicates a small risk for acquiring P. aeruginosa from dental sessions, which is however equal to the yearly 'natural background' incidence (1-2%) of acquisition of P. aeruginosa in our CF centre.