Rapid identification of <it>Burkholderia mallei</it> and <it>Burkholderia pseudomallei</it> by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing
<p>Abstract</p> <p>Background</p> <p><it>Burkholderia (B.) pseudomallei</it> and <it>B. mallei</it> are genetically closely related species. <it>B. pseudomallei</it> causes melioidosis in humans and animals, whereas <it>B. malle...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2012-10-01
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| Series: | BMC Microbiology |
| Online Access: | http://www.biomedcentral.com/1471-2180/12/229 |
| _version_ | 1811247023659155456 |
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| author | Karger Axel Stock Rüdiger Ziller Mario Elschner Mandy C Bettin Barbara Melzer Falk Maier Thomas Kostrzewa Markus Scholz Holger C Neubauer Heinrich Tomaso Herbert |
| author_facet | Karger Axel Stock Rüdiger Ziller Mario Elschner Mandy C Bettin Barbara Melzer Falk Maier Thomas Kostrzewa Markus Scholz Holger C Neubauer Heinrich Tomaso Herbert |
| author_sort | Karger Axel |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p><it>Burkholderia (B.) pseudomallei</it> and <it>B. mallei</it> are genetically closely related species. <it>B. pseudomallei</it> causes melioidosis in humans and animals, whereas <it>B. mallei</it> is the causative agent of glanders in equines and rarely also in humans. Both agents have been classified by the CDC as priority category B biological agents. Rapid identification is crucial, because both agents are intrinsically resistant to many antibiotics. Matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-TOF MS) has the potential of rapid and reliable identification of pathogens, but is limited by the availability of a database containing validated reference spectra. The aim of this study was to evaluate the use of MALDI-TOF MS for the rapid and reliable identification and differentiation of <it>B. pseudomallei</it> and <it>B. mallei</it> and to build up a reliable reference database for both organisms.</p> <p>Results</p> <p>A collection of ten <it>B. pseudomallei</it> and seventeen <it>B. mallei</it> strains was used to generate a library of reference spectra. Samples of both species could be identified by MALDI-TOF MS, if a dedicated subset of the reference spectra library was used. In comparison with samples representing <it>B. mallei</it>, higher genetic diversity among <it>B. pseudomallei</it> was reflected in the higher average Eucledian distances between the mass spectra and a broader range of identification score values obtained with commercial software for the identification of microorganisms. The type strain of <it>B. pseudomallei</it> (ATCC 23343) was isolated decades ago and is outstanding in the spectrum-based dendrograms probably due to massive methylations as indicated by two intensive series of mass increments of 14 Da specifically and reproducibly found in the spectra of this strain.</p> <p>Conclusions</p> <p>Handling of pathogens under BSL 3 conditions is dangerous and cumbersome but can be minimized by inactivation of bacteria with ethanol, subsequent protein extraction under BSL 1 conditions and MALDI-TOF MS analysis being faster than nucleic amplification methods. Our spectra demonstrated a higher homogeneity in <it>B. mallei</it> than in <it>B. pseudomallei</it> isolates. As expected for closely related species, the identification process with MALDI Biotyper software (Bruker Daltonik GmbH, Bremen, Germany) requires the careful selection of spectra from reference strains. When a dedicated reference set is used and spectra of high quality are acquired, it is possible to distinguish both species unambiguously. The need for a careful curation of reference spectra databases is stressed.</p> |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-04-12T15:03:21Z |
| publishDate | 2012-10-01 |
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| series | BMC Microbiology |
| spelling | doaj.art-7449cc835c654340b688bd7d0adefbc42022-12-22T03:28:02ZengBMCBMC Microbiology1471-21802012-10-0112122910.1186/1471-2180-12-229Rapid identification of <it>Burkholderia mallei</it> and <it>Burkholderia pseudomallei</it> by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typingKarger AxelStock RüdigerZiller MarioElschner Mandy CBettin BarbaraMelzer FalkMaier ThomasKostrzewa MarkusScholz Holger CNeubauer HeinrichTomaso Herbert<p>Abstract</p> <p>Background</p> <p><it>Burkholderia (B.) pseudomallei</it> and <it>B. mallei</it> are genetically closely related species. <it>B. pseudomallei</it> causes melioidosis in humans and animals, whereas <it>B. mallei</it> is the causative agent of glanders in equines and rarely also in humans. Both agents have been classified by the CDC as priority category B biological agents. Rapid identification is crucial, because both agents are intrinsically resistant to many antibiotics. Matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-TOF MS) has the potential of rapid and reliable identification of pathogens, but is limited by the availability of a database containing validated reference spectra. The aim of this study was to evaluate the use of MALDI-TOF MS for the rapid and reliable identification and differentiation of <it>B. pseudomallei</it> and <it>B. mallei</it> and to build up a reliable reference database for both organisms.</p> <p>Results</p> <p>A collection of ten <it>B. pseudomallei</it> and seventeen <it>B. mallei</it> strains was used to generate a library of reference spectra. Samples of both species could be identified by MALDI-TOF MS, if a dedicated subset of the reference spectra library was used. In comparison with samples representing <it>B. mallei</it>, higher genetic diversity among <it>B. pseudomallei</it> was reflected in the higher average Eucledian distances between the mass spectra and a broader range of identification score values obtained with commercial software for the identification of microorganisms. The type strain of <it>B. pseudomallei</it> (ATCC 23343) was isolated decades ago and is outstanding in the spectrum-based dendrograms probably due to massive methylations as indicated by two intensive series of mass increments of 14 Da specifically and reproducibly found in the spectra of this strain.</p> <p>Conclusions</p> <p>Handling of pathogens under BSL 3 conditions is dangerous and cumbersome but can be minimized by inactivation of bacteria with ethanol, subsequent protein extraction under BSL 1 conditions and MALDI-TOF MS analysis being faster than nucleic amplification methods. Our spectra demonstrated a higher homogeneity in <it>B. mallei</it> than in <it>B. pseudomallei</it> isolates. As expected for closely related species, the identification process with MALDI Biotyper software (Bruker Daltonik GmbH, Bremen, Germany) requires the careful selection of spectra from reference strains. When a dedicated reference set is used and spectra of high quality are acquired, it is possible to distinguish both species unambiguously. The need for a careful curation of reference spectra databases is stressed.</p>http://www.biomedcentral.com/1471-2180/12/229 |
| spellingShingle | Karger Axel Stock Rüdiger Ziller Mario Elschner Mandy C Bettin Barbara Melzer Falk Maier Thomas Kostrzewa Markus Scholz Holger C Neubauer Heinrich Tomaso Herbert Rapid identification of <it>Burkholderia mallei</it> and <it>Burkholderia pseudomallei</it> by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing BMC Microbiology |
| title | Rapid identification of <it>Burkholderia mallei</it> and <it>Burkholderia pseudomallei</it> by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing |
| title_full | Rapid identification of <it>Burkholderia mallei</it> and <it>Burkholderia pseudomallei</it> by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing |
| title_fullStr | Rapid identification of <it>Burkholderia mallei</it> and <it>Burkholderia pseudomallei</it> by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing |
| title_full_unstemmed | Rapid identification of <it>Burkholderia mallei</it> and <it>Burkholderia pseudomallei</it> by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing |
| title_short | Rapid identification of <it>Burkholderia mallei</it> and <it>Burkholderia pseudomallei</it> by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing |
| title_sort | rapid identification of it burkholderia mallei it and it burkholderia pseudomallei it by intact cell matrix assisted laser desorption ionisation mass spectrometric typing |
| url | http://www.biomedcentral.com/1471-2180/12/229 |
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