VITEK MS (mass spectrometry)

VITEK MS (mass spectrometry)

VITEK MS

Background

The Vitek mass spectrometry machine works by the MALDI-TOF principle, which is, matrix assisted laser desorption ionization time of flight. This machine identifies bacteria by determining the mass/charge ratio of the proteins (proteomics) present in the bacterium cell.

Mass spectrometry is an analytical technique for determining the elemental composition of a sample by sorting and counting molecules.

A special slide with 48 spots is used for isolate identification

Cellular components detected for bacterial identification, are:-

• Proteins, lipids and polysaccharides
• Proteins detected are those that are extractable, soluble, moderately hydrophilic, stable, and abundant.
• 20-30 proteins directly match with the theoretical masses of ribosomal proteins in the sequence database.
• It is efficient, short turnaround time and safe.

           The Vitek-MS consists of three modules: -

• The source – Extracts ions from sample
• The analyzer – Separates ions by mass/ charge
• The detector – Detects the ions from the bacterial proteins

    With the Vitek MS machine, pure bacterial isolates can be identified to species level within 5-10 minutes

VITEK 2 COMPACT

Background

The VITEK® 2 System is intended for the automated identification and antimicrobial susceptibility testing of most clinically and/or industry significant organisms (bacteria and yeast) routinely isolated in a microbiology laboratory. The VITEK® 2 System is only intended to be used with the proprietary VITEK® 2 identification (ID) and antimicrobial susceptibility (AST) test cards. Each ID card has 64 wells of biochemical substrates for bacterial growth while the AST cards are abbreviated automated form of the conventional double dilution of antibiotics for minimum inhibition concentration (MIC) using the CLSI method of interpretation. The system benefits the microbiology laboratory, prescribing clinicians, as well as patients due to its unique capability for rapid testing and result reporting.

The system uses fluorescence technology for bacterial identification and Turbidimetric method for AST.

Bacterial identification with the Vitek 2 compact machine, takes about 6 hours while AST take 16-18 hours.