Stenotrophomonas interspecies differentiation and identification by gyrB sequence analysis

Authors

  • Liselott A. Svensson-Stadler,

    Corresponding author
    • Culture Collection University of Gothenburg (CCUG), Department of Infectious Disease, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden
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  • Sashka A. Mihaylova,

    1. Department of Microbiology, Virology and Medical Genetics, Medical University, Pleven, Bulgaria
    2. Microbiology and Virology Laboratory, Pleven University Hospital, Pleven, Bulgaria
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  • Edward R.B. Moore

    1. Culture Collection University of Gothenburg (CCUG), Department of Infectious Disease, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden
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Correspondence: Liselott A. Svensson-Stadler, Culture Collection University of Gothenburg (CCUG), Department of Infectious Disease, University of Gothenburg, PO Box 7193, SE-40234 Gothenburg, Sweden. Tel.: +46 31 342 4696; fax: +46 31 829617; e-mail: liselott@ccug.se

Abstract

Stenotrophomonas species are found commonly in environmental and clinical samples; Stenotrophomonas maltophilia is an important opportunistic pathogen of humans. Traditional phenotyping protocols, as well as genotyping by 16S rRNA gene sequence analysis, do not reliably distinguish the species of Stenotrophomonas. Sequence analyses of two targeted PCR-amplified regions of the gyrB gene, which encodes the β-subunit of DNA gyrase, enabled resolution and identification of these species. Most type strains of the different species of Stenotrophomonas exhibited more than 7% dissimilarity in the gyrB gene sequences. Among these, strains identified as the same species exhibited sequence dissimilarities up to 4.6% and 5.9% for the two regions, respectively. Strains identified as S. maltophilia, with 16S rRNA gene sequence similarities > 99.0%, were grouped within a ‘S. maltophilia complex’; these organisms exhibited gyrB similarities as low as 93%. Many of these strains possessed genomic DNA similarities with the type strain of S. maltophilia CCUG 5866T below 70%. These data, including gyrB sequence comparisons, indicate that strains identified as S. maltophilia may comprise distinct, new species.

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