Detection of a Widespread Clone of Pseudomonas aeruginosa in a Pediatric Cystic Fibrosis Clinic

Abstract

Unrelated children with CF dying from severe lung disease, we A mucoid strain of P. aeruginosa had been newly identified determined its prevalence within a large CF clinic using pulsed-field in all five patients within 0.5-16 months of their deaths. Subse- gel electrophoresis and random amplified polymorphic DNA assays. quently, pulsed-field gel electrophoresis (PFGE) testing of The clinical status of P. aeruginosa-infected patients was also deter- these and other P. aeruginosa isolates from this cohort re- mined. Between September and December 1999, 152 patients, aged vealed an identical macrorestriction pattern among 8 of 27 3.9-20.7 years, provided sputum for culture. P. aeruginosa was de- infected subjects, including all five who had died. tected in 118 children of mean (SD) age 13.5 (3.8) years. The geno- The cluster of deaths in these young patients sharing a typing techniques were concordant, showing that 65 (55%) in- genotypically identical strain of P. aeruginosa was unex- fected patients carried an indistinguishable or closely related strain. pected. To investigate the possibility of an outbreak and to No distinctive antibiogram or environmental reservoir was found. help guide infection-control policies, we performed a cross- Patients with the clonal strain were more likely than those with sectional study to identify the distribution of the clonal strain unrelated isolates to have been hospitalized in the preceding 12 within the CF clinic population, using two independent geno- months for respiratory exacerbations. This study demonstrates ex- mic fingerprinting methods. The clinical status of children tensive spread of a single, clonal strain of P. aeruginosa in a large pediatric CF clinic. Whether this strain is also more virulent than with P. aeruginosa was also determined. sporadic isolates remains to be determined. As transmissible strains could emerge elsewhere, other CF clinics may also need to consider METHODS molecular methods of surveillance for cross-infection. The CF Clinic