MALDI-TOF MS (matrix-assisted laser desorption ionisation — time of flight mass spectrometry) has revolutionised bacterial identification in clinical microbiology. Its primary principle of identification is:
- A Comparison of ribosomal protein spectral fingerprint of the unknown organism to a reference database ✓
- B Detection of specific antibiotic resistance genes by hybridisation probes
- C Biochemical substrate fermentation pattern matched to API database
- D Whole genome sequencing compared to NCBI database in real time
Correct answer: A. Comparison of ribosomal protein spectral fingerprint of the unknown organism to a reference database
Explanation
MALDI-TOF MS ionises proteins (predominantly ribosomal proteins) from intact bacterial cells. The resulting mass spectrum of protein peaks serves as a unique fingerprint that is compared to a reference database (Bruker Biotyper, Vitek MS bioMérieux). Identification to species level is achieved in <10 minutes from a single colony. This has replaced conventional biochemical identification systems (API strips) for routine bacteria, mycobacteria (with modifications), and yeasts. It does not directly detect resistance genes or perform WGS.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.