65 Clinical outcomes of chronic “Prairie Epidemic Strain” Pseudomonas aeruginosa infection in adults with cystic fibrosis

Objectives Transmissible Pseudomonas aeruginosa (PA) strains have been described in CF and may be associated with a poorer prognosis. The "Prairie Epidemic Strain" (PES) has been recently identified in up to 30% of patients at prairie-based CF centres, however, its clinical impact remains to be determined. Methods A cohort study of adults with cystic fibrosis from 1981–2014 was conducted and all PA isolates from clinical visits were prospectively collected. PA strain typing at clinic enrolment, and most recent was conducted by PFGE. Patients were divided into one of four cohorts: no PA, transient PA, unique chronic PA, and chronic PES. Random effects and proportional Cox hazard models were conducted for outcome of death, transplantation and FEV1% decline. Results 204 patients (54% male) with CF were analysed: 38 no PA, 20 transient PA, 103 unique PA, 43 PES. Baseline FEV1% was lowest in the chronic PES group (p = 0.002). Overall rate of FEV1% decline was –1.19%/year (95% CI: –1.41 to –0.97, p Conclusion Chronic PES infection is significantly associated with a greater rate of FEV1% decline and risk of lung transplantation but not with increased risk of death compared to no PA infection.