AST Flashcards
Performed on bacteria isolated from clinical specimens
AST
AST stands for
Antibiotic Susceptibility Testing
AST provides in-vitro testing of a bacterial pathogen to a setof available antibiotics to determine it’s
antibiogram
antibogram is also knows as
susceptibility profile
TRUE OR FALSE
AST is performed on a bacterial isolate that is not the probable cause of infection
FALSE
should be the probable cause of infection
TRUE OR FALSE
AST is not performed on bacterial isolates that are predictably susceptible to a certain agent
TRUE
increase or decrease
AST provides information on the _______ of the antimicrobial susceptibility
decrease
Body Site
do not perform AST on bacteria isolated from it’s
natural habitat
fill in the blanks
isolation from a ________ is less likely to be contaminated
pure culture
indicator in urine that’s possibly due to contamination
> 2 species at > 10⁵ CFU/mL
Host Status
Normal Flora might be the cause of the cause of the infection in cases of
immunocompromised patients
Standardization of AST
3 important purposes:
1.** To optimize bacterial growth conditions **to ensure that the inhibition of growth can be attributed to the antimicrobial agent
2. To optimize conditions for maintaining antimicrobial integrity and activity, attributing the failure to inhibit bacterial growth to organism-associated resitance
3. To maintain reproducibility and consistency in the resistance profile of an organism, regardless of what laboratory performs the test
Standardization of AST
Standardized Components
- Bacterial inoculum size
- Growth medium
- pH
- Cation concentration
- Blood and serum supplements
- Thymidine content - incubation atmosphere
- incubation temperature
- incubation duration ‘antimicrobial concentrations
Standards are updated and published by
CLSI
CLSI stands for
Clinical and Laboratory Standards Institute
