title: Multicenter evaluation of the Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry system for identification of Gram-positive aerobic bacteria.
abstract: Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) is gaining momentum as a tool for bacterial identification in the clinical microbiology laboratory. Compared with conventional methods, this technology can more readily and conveniently identify a wide range of organisms. Here, we report the findings from a multicenter study to evaluate the Vitek MS v2.0 system (bioMérieux, Inc.) for the identification of aerobic Gram-positive bacteria. A total of 1,146 unique isolates, representing 13 genera and 42 species, were analyzed, and results were compared to those obtained by nucleic acid sequence-based identification as the reference method. For 1,063 of 1,146 isolates (92.8%), the Vitek MS provided a single identification that was accurate to the species level. For an additional 31 isolates (2.7%), multiple possible identifications were provided, all correct at the genus level. Mixed-genus or single-choice incorrect identifications were provided for 18 isolates (1.6%). Although no identification was obtained for 33 isolates (2.9%), there was no specific bacterial species for which the Vitek MS consistently failed to provide identification. In a subset of 463 isolates representing commonly encountered important pathogens, 95% were accurately identified to the species level and there were no misidentifications. Also, in all but one instance, the Vitek MS correctly differentiated Streptococcus pneumoniae from other viridans group streptococci. The findings demonstrate that the Vitek MS system is highly accurate for the identification of Gram-positive aerobic bacteria in the clinical laboratory setting.
authors: Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. jrychert@partners.org
authors: Jenna
authors: J
authors: Rychert
authors: Carey-Ann D
authors: CA
authors: Burnham
authors: Maureen
authors: M
authors: Bythrow
authors: Omai B
authors: OB
authors: Garner
authors: Christine C
authors: CC
authors: Ginocchio
authors: Rebecca
authors: R
authors: Jennemann
authors: Michael A
authors: MA
authors: Lewinski
authors: Ryhana
authors: R
authors: Manji
authors: A Brian
authors: AB
authors: Mochon
authors: Gary W
authors: GW
authors: Procop
authors: Sandra S
authors: SS
authors: Richter
authors: Linda
authors: L
authors: Sercia
authors: Lars F
authors: LF
authors: Westblade
authors: Mary Jane
authors: MJ
authors: Ferraro
authors: John A
authors: JA
authors: Branda
mesh_terms: D001420:Bacteria, Aerobic / Q000737:chemistry / Q000145:classification* / Q000302:isolation & purification*; D001431:Bacteriological Techniques / Q000379:methods*; D003951:Diagnostic Errors / Q000706:statistics & numerical data; D006094:Gram-Positive Bacteria / Q000737:chemistry / Q000145:classification* / Q000302:isolation & purification*; D006801:Humans; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
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