P82 EFFECT OF A RATIONAL CROSS-INFECTION CONTROL POLICY ON THE SPREAD OF A TRANSMISSIBLE PSEUDOMONAS AERUGINOSA STRAIN

A. Ashish, M. Shaw, T. S. Jordan, E. Spencer, H. G. Tan, A. Collins, B. Govin, M. Ledson, M. J. Walshaw. Liverpool Heart and Chest Hospital, Liverpool, UK

Background Strategies to prevent chronic lung infection with Pseudomonas aeruginosa (Psa) in cystic fibrosis (CF) include early eradication and the prevention of cross-infection by patient segregation. However, cohorting patients into those with and without Psa infection does prevent superinfection by transmissible strains and is illogical since, by definition, unique strains pose no threat to non-Psa infected patients. We have a large cohort of patients infected with the Liverpool Epidemic Strain (LES), inherited from the paediatric sector, but no cohorts of other transmissible strains. In 2003 we introduced a rational cross-infection policy where those infected with transmissible strains are segregated from those with unique strains who are not separated from patients without chronic Psa infection. To ensure that cross-infection/superinfection does not occur, Psa genotypes are regularly analysed. We now report 6 years’ experience of this cross-infection policy.

Methods Individual Psa genotypes are identified using PCR (polymerase chain reaction) from sputum samples obtained from all our patients with CF (every 3 months for LES negative and yearly for LES positive). We looked at the prevalence and cross-infection/superinfection rates between LES-infected patients and the remainder between 2003 and 2008.

Results There was a decline in the proportion of patients with LES infection (from 71% to 56%) and an increase in those with unique strains (from 23% to 27%) and without Psa infection (from 8% to 33%), all due to a decrease in the proportion of Psa-infected patients from the paediatric sector (table 1). Superinfection is rare, all due to contact outside the healthcare environment, and there have been no new cases of chronic Psa infection in those who were previously uninfected.

Conclusions This study demonstrates …