CDC group IV c-2: a new Ralstonia species close to Ralstonia eutropha

CDC group IV c-2, an environmental gram-negative bacillus recently proposed for inclusion in the genus Ralstonia, has been isolated in several human i nfections. Biochemical characterization and 16S ribosomal DNA (rDNA) sequen cing with phylogenetic analysis were used to characterize eight clinical is olates and four type strains. Other typing tools, such as pulsed-field gel electrophoresis (PFGE) and randomly amplified polymorphic DNA (RAPD) analys is, were also used. PFGE typing of clinical isolates was unsuccessful becau se the DNA was degraded, and RAPD analysis was poorly discriminatory. In co ntrast, the type strains were clearly distinguished with both PFGE and RAPD analysis. All of the 16S rDNA sequences were identical. Comparison of the 16S rDNA sequences to the GenBank sequences showed that they were consisten t with CDC group IV c-2 belonging to the genus Ralstonia, The closest match es were obtained with Ralstonia eutropha. However, four differences in 32 b iochemical tests separated R. eutropha from CDC group TV c-2, which suggest s that CDC group IV c-2 is a new species of the genus Ralstonia.