Clinical Microbiological Testing Methods Flashcards
Understand the need for identification and susceptibility testing in bacterial infections. Differentiate the types of identification methods/systems – Pros and Cons. Differentiate the types of susceptibility testing methods/systems – Pros and Cons. Understand the clinical importance and implications of identification and susceptibility testing for both the physician and patient.
What is a antibiotic sensitivity test?
A laboratory test which determines how effective antibiotic therapy MIGHT BE against a bacterial infection.
What are the biochemical ways to detect a bacteria?
- Catalase
- Oxidase
- Coagulase
- Analytical Profile Index kit
- VITEK 2
What does the catalase test do?
Differentiates between Staph and Strep
What does the oxidase test do?
Differentiates between Pseudomonas and E. coli
What does the coagulase test do?
Differentiates between S. aureus and S. epidermidis
When gram staining, what component attaches to the G+ organisms?
Purple crystal stain
When gram staining, what component attaches to the G- organisms?
Pink safranin counterstain
What is the order of gram staining?
Purple stain, iodine, alcohol, then pink safranin
What is the purpose of iodine in gram staining?
Acts as an morbant
What is the purpose of alcohol in gram staining?
Decolorization
What is the purpose of the Eosin-methylene blue (EMB)
test?
Differentiates lactose fermenters (E. coli) from non-fermenters
What is the purpose of the MacConkey agar test?
Used for the isolation of gram-negative enteric bacteria and the differentiation of lactose fermenting from lactose non-fermenting gram-negative bacteria
The use of MALDI-TOF MS identifies bacteria in what way?
Phenotypically
The use of DNA capillary electrophoresis identifies bacteria in what way?
Genotypically
What does the zone of inhibition reflect?
Susceptibility of bacterium to the antibiotic
