Phylogenetic Analysis Of Clinical Ochrobactrum Isolates And Methodological Comparison Of Strain Characterization

ObjectiveIn order to determine the phylogenetic position of58clinical isolates from Hunan, Guangdong and Beijing, which have been identified as Ochrobactrum anthropi by Commercial Viteck system, we performed a series of phenotypic and molecular analyses. We were gonging to establish a rapid and accurate method for the identification of Ochrobactrum, and furthermore, to study their mechanism of resistance between different species.MethodDuring the period from2012.2to2013.5,58clinical isolates, which have been identified as Ochrobactrum anthropi by Commercial Viteck system, were collected from some regions of China. By taking use of systematics of prokaryote, a series of phenotypic and molecular analyses were performed, such as biochemical and enzymatic activities, gene analysis(16S gene, recA gene,16-23S internal transcribed spacer), Pulsed Field Gel Electrophoresis, Random amplified polymorphic DNA PCR et al. Based on our results and a comprehensive analysis of the data, the phylogenetic tree can be constructed, and the potential novel species may be confirmed by DNA-DNA hybridization.ResultThe58clinical strains, which were initially identified as Ochrobactrum anthropi, were ultimately to be17strains of Ochrobactrum anthropi,9intermediate Ochrobactrum,4Ochrobactrum pseudogrignonense, one Ochrobactrum haematophilum and one potential novel species by DNA sequencing. There are also26isolates confirmed to be Pseudochrobactrum saccharolyticum by16S DNA sequencing, and furthermore, PFGE and RAPD analysis resembled a coincident result. Moreover, Ochrobactrum anthropi and intermediate Ochrobactrum revealed different resistance to the aminoglycosides. Conclusion Based on all the results we came to the conclusion that,1Ochrobactrum genus can accurately be identified to species level by gene sequencing.2Phylogenetic analysis reveals that the58clinical strains, initially identified as Ochrobactrum anthropic by Viteck, ultimately to be consist of17Ochrobactrum anthropi,9intermediateOchrobactrum,4Ochrobactrum pseudogrignonense,one Ochrobactrum haematophilum, one potential novel species and26Pseudochrobactrum saccharolyticum.3Pulsed field gel electrophoresis and random amplified polymorphic DNA PCR play an important role in monitoring the outbreak of nosocomial infections.4The commercial kit for the identification of Ochrobactrum genus may be not accurately enough, and further analysis of mechanism of resistance between different species can be of great value for clinical research.