Effective prevention of Pseudomonas aeruginosa cross-infection at a cystic fibrosis centre - results of a 10-year prospective study.

Pseudomonas aeruginosa is the major pathogen in chronic lung infections of individuals with cystic fibrosis (CF). Unrelated CF patients may acquire P. aeruginosa from the environment or by cross-infection in the CF setting. We tested the efficacy of measures to prevent nosocomial acquisition of P. aeruginosa at a Paediatric CF centre in a prospective 10-year study. P. aeruginosa-positive and P. aeruginosa-negative patients were seen in alternating weeks at the outpatient clinic. Faucets were equipped with filters to prevent bacterial contamination of tap water. Serial isolates were collected since the first documentation of a P. aeruginosa-positive culture and genotyped with a multimarker microarray. During the 10-year study, the annual prevalence of patients with at least one P. aeruginosa-positive culture was 39±6% in a population of 149±12 patients. P. aeruginosa was detected for the first time in 54 patients of whom 11 patients became chronically colonised with P. aeruginosa. Transient colonisations were recorded 97 times. A nosocomial acquisition of P. aeruginosa at the CF centre probably happened in one case. The worldwide dominant clones in the global P. aeruginosa population were also the most abundant clones in the panel of 324 early CF isolates. No rare clone had expanded by nosocomial transmission. It can be concluded that cross-infection with P. aeruginosa was prevented with simple hygienic measures at a CF centre that had experienced local outbreaks of nosocomial spread among unrelated patients in the past.