Discriminatory power and usefulness of pulsed- field gel electrophoresis in epidemiological studies of Pseudomonas aeruginosa

Abstract We assessed the discriminatory power of pulsed-field gel electrophoresis (PFGE) for the analysis of DNA restriction fragment length polymorphism (RFLP) in Pseudomonas aeruginosa . We determined Dra I PFGE-RFLP of DNA of unrelated clinical and environmental strains, and clinical strains isolated from two intensive care units of the Besancon University Hospital. The typeability and reproducibility was 100%. The discriminatory index was 0·998, and the DNA patterns were stable in vitro and in vivo . There was a very low correlation between PFGE-RFLP and traditional typing methods. The typeability, reproducibility, the high discriminatory power and the stability of PFGE-RFLP make this a valuable method to be used in conjunction with serotyping. Further standardization and quantitative interpretation are possible and should lead to this technique becoming a library typing system.