PRE LAB 4.2 KIRBY BAUER Flashcards
disk diffusion test was developed in the
1950s
it is refined by
william kirby
alfred bauer
which orgnization standardize this and when
world health organization in 1961
In this method, ______ are used by diffusing them in the agar medium
antibiotic discs
When the sample is in liquid form, some may use ______ wherein ___ or ______ is used to submerge the material
sterilized filter paper (whatman no.2)
oil or crude extract
On 1 agar media, ______ and _____ should be included. why?
positive and negative control
control and experimental variable cannot be separated to avoid bias
If the bacteria is sensitive to the antibiotic a ______ or a _____ is seen around the disk indicating poor growth
clear ring
zone of inhibition
However, despite the presence of zone of inhibition, its is not always considered as sensitive why?
standard diameters that classifies microoganisms as resistant, intermediate, or sensitive
the standard agar used in AST is
Mueller-Hinton agar
Pseudomonas aeruginosa exhibits a ____ pigment in MHA
green
In this shown illustration P. aeruginosa exhibited zones of inhibition on: (3) but according to CLSI it is sensitive to
Amikacin (Ak), Cefotaxime (Ce), Imipenem (I)
Amikacin, Imipenem
the standard used in comparing turbidity of bacterial suspensions
McFarland standard
1) different standards used in McFarland
2) what standard is used in AST
3) the card used to compare the turbidity of the standard from the bacterial suspension prepared
1) 0.5, 1.0, 2.0, 3.0
2) 0.5
3) wickerham card
how to prepare mcfarland standard?
1.175% barium chloride dihydrate (0.5)
1% sulfuric acid (95 mL)
storage and handling of McFarland standard
storage: room temperature 25
handling: agitate via vortex before use
