Performance of the Vitek MS v2.0 System in Distinguishing Streptococcus pneumoniaefrom Nonpneumococcal Species of the Streptococcus mitisGroup

ABSTRACTThe Vitek MS v2.0 matrix-assisted laser desorption ionization–time of flight mass spectrometry system accurately distinguished Streptococcus pneumoniaefrom nonpneumococcal S. mitisgroup species. Only 1 of 116 nonpneumococcal isolates (<1%) was misidentified as S. pneumoniae. None of 95 pneumococcal isolates was misidentified. This method provides a rapid, simple means of discriminating among these challenging organisms.