The genus Mycobacterium includes the important pathogens of the Mycobacterium tuberculosis complex (MTC) and the nontuberculous mycobacteria (NTM). NTM are increasingly the cause of opportunistic infections. This trend and the rise of antibiotic resistance in this genus demand improved differentiation among mycobacterium species.
The difference in antimicrobial susceptibility among different mycobacteria species makes identification down to the species level crucial for microbiology laboratories. Traditional methods for mycobacteria identification, primarily culture-based phenotypic methods, may take weeks and are often inaccurate. Development of commercially available molecular methods, such as nucleic acid hybridization probes, improved turnaround times significantly, but can lack specificity. Sequencing of target genes like 16S rDNA is very fast and highly accurate, but expensive and not widely available.
The recent emergence of advanced mass spectrometry (MS) technology, specifically Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight (MALDI-TOF) MS, enables microbiology laboratories to master the challenge of mycobacteria identification. The unparalleled speed of instruments, such as Bruker’s MALDI Biotyper® (MBT) system, in addition to enhanced ease-of-use, high specificity and significantly reduced cost per test, sees MALDI-TOF MS emerging as a go-to technique for mycobacteria identification.
The optional MBT Mycobacteria RUO Module for the MALDI Biotyper® is composed of a specific reference spectrum library and a software module.
The MBT compares the mass spectrum of an unknown organism with the dedicated library of reference mass spectra, which covers 182 of the currently known 201 mycobacteria. This MBT Mycobacteria Library can conveniently be applied for samples independently from growth on liquid or solid medium.
The MBT Mycobacteria RUO software Module allows processing of more challenging mass spectra than those obtained from most other bacteria. Samples flagged as mycobacteria will undergo an optimized acquisition method and spectra are automatically compared to the MBT Mycobacteria RUO Library, for sensitive and specific identification.
Mycobacteria are more challenging for MALDI-TOF MS analysis than most other bacteria. Their rigid cell wall requires a harsh method to liberate the ribosomal proteins, which moreover are not so abundantly present due to a typical lower metabolism. As identification by MALDI-TOF MS is mainly based on analysis of ribosomal proteins, a dedicated sample preparation method is needed to render high-quality spectra.
Another essential step of mycobacteria sample preparation is secure inactivation of the bacteria, which should be treated as biosafety level 3 organisms until the identification result is known.
Different to other procedures, the inactivation method of the new MBT Mycobacteria Kit does not involve boiling. The mycobacteria are conveniently inactivated by incubation with an Inactivation Reagent, at room temperature, with mechanical disruption of cell aggregates supporting the inactivation process.
The MBT Mycobacteria Kit is suitable for sample preparation for Mycobacterium spp. cultivated in liquid as well as on solid media and decreases the overall hands-on time from more than 1 hour to less than 45 minutes.
For Research Use Only. Not for use in clinical diagnostic procedures.
Please contact your local representative for availability in your country.
As of May 2021, Bruker Daltonik GmbH is now Bruker Daltonics GmbH & Co. KG.