VITEK 2 (AUTOMATION)

• VITEK® 2 (AUTOMATION)

  • Fast, accurate microbial identification, and antibiotic susceptibility testing
  • Difference with BACTEC and BACT/ALERT: VITEK 2 has the antibiotic susceptibility option.
  • Fully automated system that performs bacterial identification by biochemical analysis using colorimetry.
  • Imagine using an API method but automated.
  • We wanted automation to limit human interventions and human errors.
  • It focuses on the clinical microbiology laboratory and provides increased levels of automation and capacity for higher volume laboratories.
  • Rampant in tertiary laboratories
• VITEK® 2 (AUTOMATION)

  • ITEK 2 system can accurately identify some bacterial strains in as little as two hours.
  • In contrast, BACT/ALERT which can only indicate whether the result is positive or negative.
  • In addition to being able to identify bacteria, the VITEK 2 compact system is able to identify multiple species of yeast.
  • They also provide an option of automatic pipetting and dilution for antimicrobial susceptibility testing.
• Advantages

  • Versatile
  • Eliminated the subjectivity of reading test reactions
  • May offer automatic pipetting and dilution for antimicrobial testing
  • Provides increased levels of automation and capacity for higher volume laboratories
• Disadvantage

  • Some microorganisms that lead to correct MIC reports or yield unreliably (e.g., Pseudomonas)
• VITEK 2 Cards

  • The reagent cards have 64 wells (64 tests) that can each contain an individual test substrate.
  • More detection of various metabolic activities than API
  • Substrates measure various metabolic activities such as acidification, alkalinization, enzyme hydrolysis, and growth in the presence of inhibitory substances.
• Collab: BACTECTM and VITEK® 2 Workflow

  1. BD BACTEC FX blood culture flags positive
  2. Transfer 1 mL blood culture fluid to a 1.5 mL microcentrifuge tube.
  3. Add 200 microliter (μl) of Lysis buffer.
  4. Vortex for 10 seconds.
  5. Centrifuge for 2 min at 13000 rpm.
  6. Discard the supernatant and wash the pellet in 1 mL of wash buffer.

  Centrifuge for 2 min at 13000 rpm.
• Collab: BACTECTM and VITEK® 2 Workflow

  • 7. Centrifuge for 2 min at 13000 rpm
  • 8. Discard the supernatant then suspend the pellet in 500 microliters of sterile 0.45% normal saline and let it settle.
  • 9. Transfer bacterial suspension to make 0.50 to 0.63 McFarland standard solution.
  • 10. Set-up VITEK 2 as per manufacturer recommendations.
  • Can go directly; no need to prepare for culture plates or tubes.
• VITEK 2 Compact || Microbial Identification || AST || Automation in Microbiology Used for microbial identification and antibiotic sensitivity

  • In the machine, identification occurs in various biochemical tests.
  • Antibiotic sensitivity is done by MIC (Minimum Inhibitory Concentration) method for three different concentrations for each drop. The sensitivity is detected by the colorimetric method.
• VITEK 2 Compact || Microbial Identification || AST || Automation in Microbiology

  After the preparation of microorganism suspension, reagent cards and the suspension in the test tube are placed into their designated slots in a cassette or special rack. The cassette is loaded in the chamber

  • Once the start button is pressed, it creates a negative pressure inside the filling chamber that sucks all the air inside the chamber, including the air from the tube and card.
• VITEK 2 Compact || Microbial Identification || AST || Automation in Microbiology (

  • Air returns into the chamber; causing the organic suspension to move through the transfer tube and into the micro-channels. This fills all the test wells (Batch 2025). The dehydrated reagents are dissolved in this suspension. 
• VITEK 2 Compact || Microbial Identification || AST || Automation in Microbiology

  Once the filling is complete, as indicated by the blue light, open the filling chamber. Transfer the reagent cards into the incubator chamber. 

  • Close both the incubator chamber and filling chamber
• VITEK 2 Compact || Microbial Identification || AST || Automation in Microbiology

  • Inside the incubator chamber, barcodes are scanned in each reagent card. The tube in each card is also sealed.
  • All cards are pushed into the incubator rotator one by one.
• VITEK 2 Compact || Microbial Identification || AST || Automation in Microbiology

  • Every 15 minutes, each card undergoes scanning in the colorimetric scanner to detect color development that occurs due to biochemical reaction or sensitivity within the card.
  • After identification and sensitivity are finalized, the reagent card is pushed into the base tray.
  • Once the tray is full, all cards are discarded into the yellow bin.