Bacterial Identification by Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry

Misidentification by Bruker Biotyper³

February 2012

There were some limitations. Four of 10 Streptococcus mitis species group isolates were misidentified as Streptococcus pneumoniae using extraction. All 10 Streptococcus pneumoniae were correctly identified. This finding was previously reported. The difficulty in distinguishing between closely related species may be due to the similar composition of ribosomal proteins, the main target for matrix-assisted laser desorption ionization time of flight mass spectrometry. Two Enterococcus casseliflavus/gallinarum were misidentified as Enterococcus phoeniculicola using extraction and one by direct colony testing. Enterococcus phoeniculicola has been isolated from birds and it is not known to cause human disease. This misidentification was previously reported. In one report, correct identification of Enterococcus casseliflavus was reached when the library was updated. We tested one of our isolates using preparatory extraction after implementing an update to our library and also confirmed Enterococcus casseliflavus.

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Jump to section:

• Introduction
• Objectives
• How Does Mass Spectrometry Work?
• Types of Mass Spectrometry
• Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry
• Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry - Bruker Biotyper
• Matrix-Assisted Laser Desorption Ionization
• Matrix-Assisted Laser Desorption Ionization
• Matrix-Assisted Laser Desorption Ionization
• Time of Flight
• Mass Spectrum Generated Compared with Library (Database)
• Commercial MALDI TOF Systems for Microbial Identification
• MALDI TOF Mass Spectrometry Preparatory Extraction*
• Bacterial Identification by Mass Spectrometry
• Bacterial Identification by MALDI TOF Mass Spectrometry¹
• Bruker Biotyper MALDI TOF Mass Spectrometry versus BD Phoenix Automated Microbiology System Identification of Gram-Negative Bacilli²
• Bruker Biotyper MALDI TOF Mass Spectrometer versus BD Phoenix Automated Microbiology System Identification of Gram-Negative Bacilli²
• Bruker Biotyper MALDI TOF Mass Spectrometer versus BD Phoenix Automated Microbiology System Identification of Gram-Negative Bacilli²
• Bruker Biotyper MALDI TOF Mass Spectrometer versus BD Phoenix Automated Microbiology System Identification of Gram-Negative Bacilli²
• Bruker Biotyper MALDI TOF Mass Spectrometer versus BD Phoenix Automated Microbiology System Identification of Gram-Negative Bacilli²
• Bruker Biotyper MALDI TOF Mass Spectrometer versus BD Phoenix Automated Microbiology System Identification of Gram-Negative Bacilli²
• Identification of Gram-Positive Cocci by Bruker Biotyper Mass Spectrometry³
• Identification of Gram-Positive Cocci by Bruker Biotyper Mass Spectrometry³
• Gram-Positive Cocci³
• Gram-Positive Cocci³
• Misidentification by Bruker Biotyper³
• MALDI TOF Mass Spectrometry: Strengths
• MALDI TOF Mass Spectrometry: Limitations
• Bacteriology Laboratory Workflow Today
• Workflow with Mass Spectrometry
• References
• Acknowledgments
• Questions