Australian epidemic strain pseudomonas (AES-1) declines further in a cohort segregated cystic fibrosis clinic

Abstract

AimTo evaluate changes in prevalence of an epidemic strain of Pseudomonas aeruginosa (AES-1, Australian epidemic strain, type 1) in a paediatric cystic fibrosis (CF) centre practising cohort segregation, to describe the patients' clinical characteristics at acquisition and observe mortality rates. MethodsCohort segregation was introduced in our paediatric CF clinic January 2000. The prevalence of AES-1 was analysed in 1999, 2002 and 2007. Age at acquisition, lung function, presence of bronchiectasis, hospitalisations, prior P. aeruginosa infection and mortality rates were collected. AES-1 infection was determined by pulse-field-gel-electrophoresis (PFGE) on airway specimen cultures taken three monthly. ResultsThe prevalence of AES-1 declined from 21% in 1999 to 14% in 2002 (risk difference 7% (95% CI 1,13) p=0.0256) and to 6% in 2007 (risk difference 8% (95% CI 3,13) p=0.0018). New acquisitions after the introduction of cohort segregation were uncommon (10 by 2002 and another 7 by 2007) with a declining incidence of 3.3cases/year (1999 to 2002) compared to 1.4cases/year (2002 to 2007). Twenty-two of 32 (69%) deaths between 1999 and 2007 occurred in patients infected with AES-1. ConclusionCohort segregation has been associated with reductions in the prevalence of AES-1 in our CF clinic. Mortality was higher in patients infected with AES-1 than other organisms.