Bacterial identification and automation Flashcards
Phenotypic and genotypic laboratory tests are used to identify the microorganism causing disease. A PURE CULTURE is required for proper identification and susceptibility testing.
Work up/Identification
Use of slides for smear preparation, special staining, and manual biochemical testing.
Manual/Conventional Method
Spot indole, ONPG, Oxidase, Catalase, Bile solubility, PYR, MUG, LAP, Rapid urease, and rapid Hippurate hydrolysis.
Rapid tests (within 10 minutes)
API (Analytical Profile Index) used for identifying fermentative gram-negative bacteria using a 20 cupule strip. Bacteria are suspended in saline, incubated, and results are read after 18-24 hours with a 7-digit code profile number.
Manual Multitest System
Colorimetry, Fluorometry, or Turbidimetry detect bacterial growth using lyophilized reagents and bacterial suspension, incubated for 16-24 hours.
Automated Methods
Uses 96-well microtiter trays with substrates for identification and sensitivity testing, requiring 16-20 hours. Rapid fluorescence method identifies in 2.5 hours and sensitivity testing in 7 hours.
MicroScan System
Uses Sensititre Autoreader and Sensititre ARIS2x to identify 3 organisms on a 96-well plate with fluorescence within 5 hours or more.
TREK Diagnostic System
Uses 64-well cards for identification, sensitivity testing, and detection of multi-drug resistant isolates. Results in 16-24 hours, including anaerobic organisms. AST results are interpreted using Advance Expert System (AES) in 6-8 hours.
Vitek 2 System
Uses colorimetric and fluorometric systems with 136-well combination panels to identify bacteria in 2-12 hours and yeasts in 4-15 hours. Redox indicator panels are used for growth monitoring, AST uses manual inoculation and epicenter software for interpretation.
BD Phoenix System
Identification based on the organism’s ability to utilize 95 carbon sources in a 96-well plate with tetrazolium violet as an indicator. Available for aerobic and anaerobic gram-positive/negative bacteria and yeasts.
Biolog OmniLog System
Based on 9-20 carbon fatty acid composition of microorganisms. Identification time is 1.5-2 hours. Fatty acids are extracted and analyzed using gas chromatography after TSA-grown bacteria are incubated and treated with methanol.
Sherlock Microbial Identification System
HPLC (High-Performance Liquid Chromatography) is used for Mycobacterial identification.
Test for Mycobacterial identification
Chromatography is useful for identifying anaerobic organisms.
Useful test for anaerobic organisms
bioMerieux manual (API) and automated (Vitek 2) detects
GP, GN, Neisseria, yeast, anaerobes
Becton Dickinson (BD) Crystal E/NF BD Phoenix
GP cocci & bacilli, GN cocci & bacilli
