title: Evaluation of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry in Identification of Nontuberculous Mycobacteria.
abstract: OBJECTIVE
  Species-level identification of nontuberculous mycobacteria (NTM) is important in making decisions about the necessity and choice of antimicrobial treatment. The reason is predictable clinical significance and the susceptibility profile of specific NTM species. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is recognized as a diagnostic tool for routine identification of bacteria and yeasts in the clinical laboratory based on protein fingerprint analysis. The aim of the study was to evaluate MALDI-TOF MS in the identification of NTM.
  
  
  METHODS
  A total of 25 NTM isolates from liquid cultures were identified with both polymerase chain reaction (PCR)-based hybridization assay and MALDI-TOF MS at the University Hospital Center Zagreb.
  
  
  RESULTS
  PCR-based hybridization assay identified 96% (24/25) and MALDI-TOF MS 80% (20/25) of tested NTM isolates. Five isolates with no reliable MALDI-TOF MS identification belonged to the Mycobacterium avium-intracellulare complex. Seventy percent (14/20) of NTM isolates successfully identified with MALDI-TOF MS had a score higher than 2.0, indicating reliable species identification.
  
  
  CONCLUSIONS
  MALDI-TOF MS is a promising tool for the identification of NTM. With a further improvement of the protein extraction protocol, especially regarding the M. avium-intracellulare complex, MALDI-TOF MS could be an additional standard method for identification of NTM.
authors.forename: Ivana
authors.initials: I
authors.lastname: Mareković
authors.forename: Zrinka
authors.initials: Z
authors.lastname: Bošnjak
authors.forename: Marko
authors.initials: M
authors.lastname: Jakopović
authors.forename: Zagorka
authors.initials: Z
authors.lastname: Boras
authors.forename: Mateja
authors.initials: M
authors.lastname: Janković
authors.forename: Sanja
authors.initials: S
authors.lastname: Popović-Grle
mesh_terms: D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D015269:Mycobacterium avium Complex / Q000235:genetics / Q000302:isolation & purification; D009170:Nontuberculous Mycobacteria / Q000235:genetics* / Q000302:isolation & purification; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004269:DNA, Bacterial