Effects of segregation on an epidemic Pseudomonas aeruginosa strain in a cystic fibrosis clinic

Am J Respir Crit Care Med. 2005 May 1;171(9):1020-5. doi: 10.1164/rccm.200409-1194OC. Epub 2005 Feb 11.


The detection of a clonal Pseudomonas aeruginosa strain in 21% of children attending a cystic fibrosis clinic during 1999, which may have led to a worse prognosis, prompted strict infection control measures, including cohort segregation. We determined whether these strategies interrupted cross-infection within the clinic. Patients from 1999 were observed and a cross-sectional study of the 2002 clinic was performed. By 2002, the epidemic strain prevalence had decreased from 21 to 14% (p = 0.03), whereas the proportion of patients with nonepidemic P. aeruginosa strains was unchanged. The age- and sex-adjusted relative risk for epidemic strains among sputum producers in 2002 compared with 1999 was 0.64 (95% confidence interval, 0.47, 0.87; p = 0.004). Increased mortality or transfer to another clinic did not explain this reduction. Although children with epidemic strains may have had increased mortality (adjusted odds ratio, 2.0; 95% confidence interval, 0.6-6.8), they did not demonstrate greater morbidity than those with other P. aeruginosa isolates. Successful infection control measures provided additional indirect evidence for person-to-person transmission of an epidemic strain within the clinic. Further studies are needed to resolve whether cohort segregation completely eliminates cross-infection and if acquisition of epidemic isolates is associated with worse outcomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Bacterial Typing Techniques
  • Child
  • Cohort Studies
  • Comorbidity
  • Cross Infection
  • Cystic Fibrosis / epidemiology*
  • Disease Outbreaks / prevention & control*
  • Female
  • Humans
  • Infection Control / methods*
  • Male
  • Prevalence
  • Pseudomonas Infections / epidemiology*
  • Pseudomonas aeruginosa / classification
  • Pseudomonas aeruginosa / isolation & purification
  • Sputum / microbiology
  • Virulence