A comparative study of two different methods of sample preparation for positive blood cultures for the rapid identification of bacteria using MALDI-TOF MS.
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has lately been implemented as a solid technology for rapid microorganism identification in microbiology laboratories. This study compares two methods for bacterial separation from 85 positive blood culture before MALDI-TOF MS: (1) a conventional method that we used in our laboratory to prepare bacteria for susceptibility testing and (2) a new commercialized technique (Sepsityper). There were no significant differences in the identification of Gram-negative bacilli regardless of the bacterial separation method used. However, identification was greater for Gram-positive cocci when the Sepsityper method was used (84.15% vs. 100% in the identification to a genus level in staphylococci and 57.14% vs. 85.71% in the identification to a genus level of enterococci with the in-house and Sepsityper methods, respectively). Therefore, the Sepsityper method to prepare bacteria from a positive blood culture is more adequate for the further identification of Gram-positive cocci by MALDI-TOF MS.
Department of Clinical Microbiology, Hospital Clinic, CRESIB/IDIBAPS, School of Medicine, University of Barcelona, and Servei de Microbiologia, Hospital Clinic de Barcelona, Barcelona, Spain.
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Juiz
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Almela
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Melción
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Campo
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Esteban
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Pitart
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Marco
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Vila
D016470:Bacteremia / Q000175:diagnosis*; D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification*; D001431:Bacteriological Techniques / Q000379:methods*; D001769:Blood / Q000382:microbiology*; D006801:Humans; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*