131 Surveillance of Pseudomonas aeruginosa infections at the Prague CF centre

Pseudomonas aeruginosa (PA) causes chronic respiratory infections in 40−70% of adult CF patients. The infection can spread between patients as documented by identification of transmissible strains in some CF centres. The aim of this study was to set up a surveillance program for PA infections in the Prague CF centre and to map a local epidemiological situation. In 2004–2012, we collected 865 PA isolates (244 patients, 1−18 samples/patient). Three methods were compared for their suitability to be used for surveillance at the (i) intraand (ii) inter-patient level: random amplified polymorphic DNA (RAPD), multilocus sequence typing (MLST) and pulsed field gel electrophoresis (PFGE). We genotyped 350 isolates (196 pts) using RAPD; 225 of them (153 pts) were also examined by MLST and 64 isolates (42 pts) by PFGE. While all methods provided concordant results for strain carriage monitoring at the intrapatient level, RAPD failed to distinguish interpatient isolates whose unrelatedness was apparent from other two typing methods. The analysis i. was performed with RAPD in 90 patients: the replacement of one PA strain with another was observed in 19 cases (21%). The MLST-based analysis ii. revealed great heterogeneity between PA isolates (107 STs in 153 patients; single ST shared by max. 10 patients). The surveillance protocol composes of MLST for characterization of initial isolates and RAPD for subsequent isolates. If an RAPD pattern of a new isolate differs from the previous one, MLST is carried out to confirm strain replacement. An observed diversity in the PA population is indicative of accurate anti-epidemic measures set at the CF centre. Supported by IGA MZ NT12405−5.