Genotyping of Pseudomonas aeruginosa reveals high diversity, stability over time and good outcome of eradication

BackgroundGenotyping of Pseudomonas aeruginosa (P.a) is used for surveillance at our CF clinic.MethodsP.a from 1999 to 2012 were analysed, using pulsed-field gel electrophoresis (PFGE) and multiple-locus variable number of tandem repeats analysis (MLVA).ResultsAmong 232 isolates from 104 patients, we identified 78 unique strains, of which 56 were isolated from individual patients. The B-clone was isolated from 13 patients and the camp transmission clone J-strains from 8 patients at the start of the study. There was no indication of transmission within the clinic. PFGE and MLVA clone identification was in 91% agreement. For patients who provided more than 2 P.a isolates, similar strains were identified over time for 45/49 chronically- and for 6/16 intermittently-colonized patients despite, periods of no detectable P.a after eradication therapy.ConclusionsAnalyses revealed high genotypic diversity, acceptable outcome of eradication therapy and no indication of cross-infection at the CF centre.