[LAB] Exercise 8B: AST: Broth Macrodilution or Macrobroth Dilution Flashcards
what type of dilution is one of the conventional testing methods used in AST?
Broth dilution
This is a technique that uses a standardized amount of test inoculum present in Mueller Hinton Broth (MHB) and a selected antimicrobial agent.
Broth dilution
What standardized test inoculum is used in Broth dilution?
Mueller Hinton Broth and Selected antimicrobial agent
T/F: The antimicrobial agent is diluted five-fold in the test.
F.
two-fold in the test only
T/F: The minimum inhibitory concentration (MIC) is expressed in mg/dl
F.
µg/mL
This is the lowest concentration of antimicrobial agent that completely inhibits visible growth
Minimum inhibitory concentration (MIC)
T/F: The MIC can be detected semi-automated
trew
MIC can be detected v_______, a_______, or s__________ method
visually
automated or semi-automated
Name three interpretative categories once MIC has been determined
Susceptible (S)
Intermediate (I)
Resistant (R)
Name two categories of broth dilution
Broth microdilution (microbroth dilution)
Broth macrodilution (macrobroth dilution)
T/F: Main difference between broth microdilution and broth microdilution is on the volume of the MIC
F.
Volume of the MHB used dapat :)
T/F: In exercise 8B, broth microdilution was used.
F.
Broth macrodilution
(check the title of the experiment for validation <3) HAHAHA
T/F: Sterile 12mm x 100mm test tubes with screw caps were used in this experiment.
F.
13mm x 100mm dapat :)
Yes/No: In this experiment 8B, do we need to standardize the inoculum to a 0.5 McFarland Standard?
Yes.
T/F: The test antibiotic used in this experiment was Amoxicillin 20 U/mL
F.
Penicillin (working solution of 20 U/mL)
T/F: The test culture must grow on BAP
T.
T/F: For other test antibiotics a 200 µg/mL should be your working solution
T.
The adjusted inoculum is then diluted to what ratio?
1:200
T/F: The adjusted inoculum is done by adding 0.1 mL of the standardized inoculum to 19.9 mL of MHB Broth.
T.
T/F: In the preparation and standardization of the Inoculum, the final bacterial concentration is approximately 4 x 10^5 CFU/mL
T.
5 x 10^5 CFU/mL
In the test proper, test tube 1-10 will be used for the ______?
a. actual test
b. control tubes
a. actual test
In the test proper, test tube 11-13 will be used for the ______?
a. actual test
b. control tubes
b. control tubes
In the test proper, control tube - test tube 11 is the ______?
a. antibiotic control (AC)
b. broth control (BC)
c. inoculum control (IC)
c. inoculum control (IC)
In the test proper, control tube - test tube 12 is the ______?
a. antibiotic control (AC)
b. broth control (BC)
c. inoculum control (IC)
b. broth control (BC)
In the test proper, control tube - test tube 13 is the ______?
a. antibiotic control (AC)
b. broth control (BC)
c. inoculum control (IC)
a. antibiotic control (AC)
In the test proper, the test tubes should be incubated at what degree Celsius?
35°C - 37°C
T/F: Mix each tube and incubate them at 35-37°C ambient air for 18-24 hrs.
T.
T/F: We observe visible growth in the form of TURBIDITY
T.
T/F: prior to interpretation, observe if the ACTUAL TEST are working properly
F.
CONTROL TUBES
T/F: Test tube 11 - must show VISIBLE GROWTH
T.
because inoculum control
Test tube 12 - must show VISIBLE GROWTH or NO VISIBLE GROWTH?
NO VISIBLE GROWTH
because broth control
Test tube 13 - must show VISIBLE GROWTH or NO VISIBLE GROWTH?
NO VISIBLE GROWTH
because antibiotic control
T/F: In determining the MIC, we determine the tube with the HIGHEST antibiotic concentration
F.
LOWEST
In determining the MIC, we determine the tube with the lowest antibiotic concentration showing _______? (visible growth or no visible growth)
no visible growth
T/F: In the determination of MBC, we pipette 0.01 mL from each test tube with no visible growth and subculture to individual CAP plates
F.
BAP plates
T/F: same with MIC, we incubate the plates for 18-24 hrs at 35-37°C ambient air
T.
MIC or MBC: It has the lowest antibiotic concentration, which results in 99% killing of organisms.
MCB (Minumum Bactericidal Concentration)
MIC or MBC: It can be determined by identifying the plate with the lowest antibiotic showing no visible growth
MCB (Minumum Bactericidal Concentration)
T/F: In broth macrodilution test, fastidious bacteria are required
T.
The breakpoint of growth inhibition is visible in what tube/s?
(choose only 2 tubes from tubes 1-10)
between tube 5 and tube 6
What is the main difference between Broth microdilution test and Broth macrodilution test?
Volume of MHB (Mueller-Hinton Broth)
MIC or MBC: Lowest concentration that prevents the in vitro growth of bacteria
MIC (Minimum Inhibitory Concentration)
MIC or MBC: Test tube that shows the lowest concentration without any colony growth
MBC (Minimum Bactericidal Concentration)
