Molecular Techniques for the Identification of Clinical and Environmental Achromobacter strains

• Background: The genus Achromobacter (βetaproteobacteria) comprises six species isolated from different sources, most from clinical samples. The ability to detect and correctly identify A. xylosoxidans and related Gram-negative, non-fermenting species is essential for patients with cystic fibrosis, as well as in nosocomial infections. Traditional phenotyping is not adequate for reliable, definitive identifications of Achromobacter species. Furthermore, sequence analyses of 16S rRNA gene sequences are also not able insure accurate identification of Achromobacter species, due to the limited resolution of the rRNA genes (greater than 98.5% to each other). Objectives: The objective of this study has been to establish a genotypic, multi-locus sequence analysis (MLSA), analysis for the reliable, definitive and cost-effective identification of Achromobacter species, and to apply the molecular tools for typing and identification of clinical isolates. Methods: 1) Selection of phenotypically well-described strains of Achromobacter species isolated from different sources (clinical and environmental). 2) Development of a MLSA strategy based on sequences of 16S rRNA, inter-genic spacer regions (IGS1), DNA gyrase subunit B (gyrB), and RNA polymerase subunit B (rpoB). 3) Comparison and correlation of MLSA data with other methodologies: DNA-DNA hybridisation; fingerprinting analysis; cellular fatty acids analysis; and MALDI-TOF mass spectrometry analyses. Results: Individual phylogenetic trees, as well as combined datasets were compared. The combined analysis of the MLSA data provided differentiation at the intra- and the interspecies levels and reliable identifications of isolates of Achromobacter spp. Conclusions: The MLSA methodology described allows for the rapid and reliable identification of the Achromobacter species, distinguished from related Gram-negative non-fermenting organisms, and is also useful for strain differentiation and typing in molecular epidemiological studies.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biologisk systematik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biological Systematics (hsv//eng)

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