title: Rapid identification of clinical mycobacterial isolates by protein profiling using matrix assisted laser desorption ionization-time of flight mass spectrometry.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the identification of Mycobacterium tuberculosis which is often plagued with ambiguity. It is a time consuming process requiring 4-8 weeks after culture positivity, thereby delaying therapeutic intervention. For a successful treatment and disease management, timely diagnosis is imperative. We evaluated a rapid, proteomic based technique for identification of clinical mycobacterial isolates by protein profiling using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS).
  
  
  METHODS
  Freshly grown mycobacterial isolates were used. Acetonitrile/trifluoroacetic acid extraction procedure was carried out, following which cinnamic acid charged plates were subjected to identification by MALDI-TOF MS.
  
  
  RESULTS
  A comparative analysis of 42 clinical mycobacterial isolates using the MALDI-TOF MS and conventional techniques was carried out. Among these, 97.61% were found to corroborate with the standard methods at genus level and 85.36% were accurate till the species level. One out of 42 was not in accord with the conventional assays because MALDI-TOF MS established it as Mycobacterium tuberculosis (log (score)>2.0) and conventional methods established it to be non-tuberculous Mycobacterium.
  
  
  CONCLUSIONS
  MALDI-TOF MS was found to be an accurate, rapid, cost effective and robust system for identification of mycobacterial species. This innovative approach holds promise for early therapeutic intervention leading to better patient care.
authors.affiliation: Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: A
authors.initials: A
authors.lastname: Panda
authors.forename: S
authors.initials: S
authors.lastname: Kurapati
authors.forename: J C
authors.initials: JC
authors.lastname: Samantaray
authors.forename: V P
authors.initials: VP
authors.lastname: Myneedu
authors.forename: A
authors.initials: A
authors.lastname: Verma
authors.forename: A
authors.initials: A
authors.lastname: Srinivasan
authors.forename: H
authors.initials: H
authors.lastname: Ahmad
authors.forename: D
authors.initials: D
authors.lastname: Behera
authors.forename: U B
authors.initials: UB
authors.lastname: Singh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001426:Bacterial Proteins / Q000032:analysis* / Q000302:isolation & purification; D001431:Bacteriological Techniques / Q000191:economics / Q000379:methods*; D002648:Child; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000737:chemistry* / Q000302:isolation & purification*; D020543:Proteome / Q000032:analysis* / Q000302:isolation & purification; D013048:Specimen Handling / Q000191:economics / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000191:economics / Q000379:methods*; D013997:Time Factors; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D001426:Bacterial Proteins; D020543:Proteome