Kirby bauer test Flashcards
purpose of AST
To test the effectiveness of antibiotics
To give information to physicians on the proper antibiotics that will give to the
patient
most common diffusion method of AST
Kirby- Bauer Diffusion Method
diffusion method of AST where in antibiotics is in liquid form
Agar Cup Diffusion Method
diffusion method of AST where in metal cylinder is incorporated and there, liquid antibiotic will be added
Agar Cylinder Diffusion Method
antibiotics in strips
Gradient Diffusion Method
2 types of dilution method
micro dilution
macro dilution
Zone of inhibition is being measured using
vernier caliper
Standardized Pure Inoculum
0.5 mcfarland
It has a calibration, with a green light indicating that a 0.5 suspension is
already achieved. If the light is red, we will add demineralized water or NSS
Densitometer
Mueller Hinton Agar pH
7.2 to 7.4
Mueller Hinton Agar depth
5 mm
Staphylococcus spp. & MRSA
MHA + 5% Sodium chloride
Haemophilus spp., Streptococci spp.
MHA + 5% defibrinated blood sheep
Proper spacing in MHA
18 mm or more than 15mm
number of disk in big MHA (150mm)
12
number of disk in small MHA (100mm)
6
Indicates an organism may require a higher dose of antibiotic for longer period of time to be inhibited
Intermediate
Indicates an organism is inhibited by recommended dose
Susceptible
Indicates an organism is not inhibited by recommended dose
Resistance
Zone of inhibition is reported in
millimeters (mm)
For microorganisms with unpredictable susceptibilities, determine what is the lowest concentration of antibiotic
in which the bacteria will be inhibited.
Minumum Inhibitory Concentration
Set up for Macrobroth/ Tube Dilution method
Mueller Hinton broth + Antibiotics + Inoculums of uniform volume.
Set up for alamar system
Mueller Hinton broth + organism + Alamar blue indicator
This system uses a traythat would contain the antibiotics
Alamar System
