title: Performance of the Vitek MS matrix-assisted laser desorption ionization time-of-flight mass spectrometry system for identification of Gram-positive cocci routinely isolated in clinical microbiology laboratories.
abstract: We evaluated the performance of the Vitek MS for identification of Gram-positive cocci routinely isolated in clinical microbiology laboratories. With a total of 424 well-characterized isolates, the results of the Vitek MS were compared to those of conventional methods and 16S rRNA gene sequencing. The Vitek MS correctly identified 97.9 % of the isolates tested to species level. The Vitek MS correctly identified the species of 97.2 % of the staphylococci (95.9 % of coagulase-negative staphylococci), 97.8 % of the streptococci, and 100 % of the enterococci. For the identification of Gram-positive cocci isolates, the overall concordance rate between conventional identification and the Vitek MS was 94.5 %. The Vitek MS matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) system can be a reliable and rapid method for the identification of most relevant Gram-positive cocci. In addition, expanding the database of the Vitek MS, especially for coagulase-negative staphylococci, is needed to enhance the performance of the Vitek MS.
authors.affiliation: Department of Laboratory Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea.
authors.forename: Hee-Won
authors.initials: HW
authors.lastname: Moon
authors.affiliation: Neodin Medical Institute, Seoul, Republic of Korea.
authors.forename: Sun Hwa
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, Ewha Womans University School of Medicine, Seoul, Republic of Korea.
authors.forename: Hae-Sun
authors.initials: HS
authors.lastname: Chung
authors.affiliation: Department of Laboratory Medicine, Ewha Womans University School of Medicine, Seoul, Republic of Korea.
authors.forename: Miae
authors.initials: M
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Kyungwon
authors.initials: K
authors.lastname: Lee
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods; D013293:Enterococcus faecalis / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007753:Laboratories / Q000592:standards; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*; D013292:Streptococcus agalactiae / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S