MALDI-typing of bacteria and animal tissue cultures
Identification and taxonomic classification of bacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has become increasingly popular in bacteriological laboratories as ‘intact cell mass spectrometry’ (ICMS). In addition to the low cost and high speed of analysis, MALDI-typing in some cases can be a valuable complementation to classical bacteriological procedures, e.g. in cases where sub-species differentiation of bacteria is required.
MALDI-typing relies on the comparison of the sample spectrum with reference spectra from a commercial or an in-house database. Except for an authentic reference spectrum, no additional data (e.g. sequence data) of the organism to be identified is required. For bacteriological routine, our laboratory offers the identification of bacterial samples with a database containing over 3500 reference spectra, part of which is dedicated to veterinary medicine. Intact cell MALDI-spectra can also be used for phylogenetic or epidemiological studies.
Together with the FLI’s cell culture repository (Collection of Cell Lines in Veterinary Medicine, CCLV) a protocol for the characterization of cultured animal cells by ICMS was developed (Karger et al., 2010) which allows the species determination of cell cultures of unknown or doubtable origin. This technology is also applicable for characterization of ticks, which was shown in cooperation with the NRL for tick-borne diseases (Karger et al., 2012a).
- Karger A, Kampen H, Bettin B, Dautel H, Ziller M, Hoffmann B, Süss J, Klaus C. 2012a. Species determination and characterization of developmental stages of ticks by whole-animal matrix-assisted laser desorption/ionization mass spectrometry.
Ticks Tick-Borne Dis 3:78-89.
- Karger A, Stock R, Ziller M, Elschner MC, Bettin B, Melzer F, Maier T, Kostrzewa M, Scholz HC, Neubauer H, Tomaso H. 2012b. Rapid identification of Burkholderia mallei and Burkholderia pseudomallei by intact cell Matrix-assisted Laser Desorption/Ionisation mass spectrometric typing.
BMC Microbiol 12:229.
- LLöhr CV, Polster U, Kuhnert P, Karger A, Rurangirwa FR, Teifke JP. 2012. Mesenteric Lymphangitis and Sepsis Due to RTX Toxin-Producing Actinobacillus spp in 2 Foals With Hypothyroidism-Dysmaturity Syndrome.
Vet Pathol 49:592-601.
- Karger, A., M. Ziller, B. Bettin, B. Mintel, S. Schares, and L. Geue. (2011). Determination of Serotypes of Shiga Toxin-Producing Escherichia coli Isolates by Intact Cell Matrix-Assisted Laser Desorption Ionization – Time of Flight Mass Spectrometry.
Appl Environ Microbiol 77:896-905.
- Karger A, Bettin B, Lenk M, Mettenleiter TC. (2010). Rapid characterisation of cell cultures by matrix-assisted laser desorption/ionisation mass spectrometric typing.
J Virol Methods 164:116-21.