Identification of Staphylococcus aureus and Determination of Its Methicillin Resistance by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

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• 作者：Zongmin Du ; Ruifu Yang ; Zhaobiao Guo ; Yajun Song ; and Jin Wang
• 刊名：Analytical Chemistry
• 出版年：2002
• 出版时间：November 1, 2002
• 年：2002
• 卷：74
• 期：21
• 页码：5487 - 5491
• 全文大小：179K
• 年卷期：v.74,no.21(November 1, 2002)
• ISSN：1520-6882

文摘

To evaluate the performance of matrix-assisted laserdesorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS) in identifying Staphylococcus aureusand in determining its methicillin resistance, we analyzed76 S. aureus clinical isolates using a linear MALDI-TOFMS. Spectral profile data obtained were compared withthe database provided with the instrument, and 74% ofthe isolates were identified as S. aureus, as confirmedby a nuc-based PCR test. The determination of themethicillin resistance in S. aureus is based on the factthat the spectral profiles of methicillin-susceptible S.aureus (MSSA) and methicillin-resistant S. aureus(MRSA) differ greatly from each other. Replicate spectralprofiles obtained from each isolate were combined to bea representative spectrum of it, and representative spectral profiles from all the isolates constitute a user's self-established database. All the spectral profiles in thedatabase were classified into two groups based on clustering analysis, and one is for MSSA and another MRSA.There was a little discrepancy between the results fromMALDI-TOF MS and from PCR. Seven isolates that arenegative for the mecA gene by PCR were identified asMRSA by MALDI-TOF MS. The discrepancy may bepartially explained by the heterogeneous nature of methicillin resistance in S. aureus. Our results suggested thatcomparison of MALDI-TOF MS spectral profiles of microorganism could serve as a simple and rapid methodfor bacterial identification and antibiotic susceptibilityanalysis.