title: Rapid discrimination between strains of beta haemolytic streptococci by intact cell mass spectrometry.
abstract: OBJECTIVE
  Beta haemolytic streptococci belonging to Lancefield group A, B, C and G cause a wide spectrum of clinical diseases. Hence there is a need for rapid and accurate typing of these strains. The present study was undertaken to evaluate the use of intact cell matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for rapid discrimination between strains of beta haemolytic streptococci.
  
  
  METHODS
  Colonies of beta haemolytic streptococci were emulsified with chemical matrix on the sample slide, dried and analyzed by MALDI-TOF-MS.
  
  
  RESULTS
  The reproducibility of results for all groups of beta haemolytic streptococci was good and spectra obtained for Lancefield group A, C and G streptococci showed discrimination between the groups on visual comparison. A finer difference in spectrum was observed among group A streptococci isolated from different locations at different periods of time.
  
  
  CONCLUSIONS
  MALDI-TOF-MS may be a potential tool in discriminating between strains of beta haemolytic streptococci, and also in the characterisation of untypable strains of group A streptococci.
authors.affiliation: Department of Microbiology, Dr ALM Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai, India.
authors.forename: M Palani
authors.initials: MP
authors.lastname: Kumar
authors.forename: M
authors.initials: M
authors.lastname: Vairamani
authors.forename: Raju Prasada
authors.initials: RP
authors.lastname: Raju
authors.forename: Charmaine
authors.initials: C
authors.lastname: Lobo
authors.forename: N
authors.initials: N
authors.lastname: Anbumani
authors.forename: C P Girish
authors.initials: CP
authors.lastname: Kumar
authors.forename: Thangam
authors.initials: T
authors.lastname: Menon
authors.forename: S
authors.initials: S
authors.lastname: Shanmugasundaram
mesh_terms: D000293:Adolescent; D002648:Child; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013290:Streptococcal Infections / Q000175:diagnosis* / Q000382:microbiology; D013291:Streptococcus / Q000235:genetics / Q000378:metabolism*