F10 Flashcards
The best test for the susceptibility of a microorganism to antibiotics and other chemotherapeutic agents
Tube-dilution test
Paper-disc test
Both a and b
None of these
Both a and b
The smallest amount of chemotherapeutic agents required to inhibit the growth of the organism in Vitro is known as
MIC (minimum inhibitory concentration)
Thermal death point (TDP)
MBC (Minimum Bactericidal concentration)
None of these
MIC (minimum inhibitory concentration)
In Kirby-Bauer Technique, clear-zones formation around the antibiotic disc is due to__
Growth of the bacterium surrounding the disc
Lysis of the bacterial cells surrounding the disc
The destruction of paper disc (antibiotic)
None of these
Lysis of the bacterial cells surrounding the disc
Antimicrobial agents that kill the microbe, leading to cell lysis, are categorized as
bacteriostatic
bactericidal
narrow-spectrum antibiotics
super antibiotics
bactericidal
What is the standard inoculum size for the disk diffusion method?
5 x 10^8 CFU/mL
7 x 10^8 CFU/mL
10 x 10^8 CFU/mL
3 x 10^8 CFU/mL
5 x 10^8 CFU/mL
Which of the following are used as quality control measures for Kirby-Baeur Test?
Staphylococcus aureus ATCC 25923
Escherichia coli ATCC 25922
Pseudomonas aeruginosa ATCC 27853
All of the choices are correct
All of the choices are correct
Which of the following techniques cannot be used to determine the minimum inhibitory concentration of an antimicrobial drug against a particular microbe?
Etest
Micro broth dilution test
Kirby-Bauer disk diffusion test
Macro broth dilution test
Kirby-Bauer disk diffusion test
Which of the following combination is correct?
Penicillin: inhibition of cell wall synthesis
Cephalosporin: inhibition of protein synthesis
Aminoglycoside: inhibition of cell wall synthesis
Fluoroquinolones: inhibition of cell wall synthesis
Penicillin: inhibition of cell wall synthesis
The figure below shows the results after incubation of erythromycin microdilution testing of an isolate of Escherichia coli. Filled wells denote growth, empty wells denote no growth. After incubation, the contents of each well were plated on non-selective media, and the numbers of colonies growing from each are written in the appropriate well. Which of the following is the best interpretation of these results?
The minimum inhibitory concentration is 1 mg/L and the drug is bacteriostatic
The minimum inhibitory concentration is 1 mg/L and the drug is bactericidal.
The minimum inhibitory concentration is 2 mg/L and the drug is bacteriostatic
The minimum inhibitory concentration is 2 mg/L and the drug is bactericidal.
The minimum inhibitory concentration is 2 mg/L and the drug is bacteriostatic
valuated by the disc diffusion (Kirby-Bauer) test where thin filter-paper waters impregnated with antibiotics are placed on the surface of an agar plate swabbed uniformly with bacteria. The figure below illustrates the result for this test when equal concentrations of five different antibiotics (A-E) were used. Each drug had the same diffusion characteristics. To which antibiotic is this bacterial culture most sensitive?
Antibiotic A
Antibiotic B
Antibiotic C
Antibiotic D
Antibiotic A
A researcher wanted to determine the antibacterial effect of Amoxicillin/Clavulanic Acid against Escherichia coli by measuring the MBC. Based on the image given above, which of the following tubes is the MBC?
4 ug/mL
8 ug/mL
16 ug/mL
32 ug/mL
16 ug/mL
In the Kirby-Bauer disk diffusion test, the____ of the zone of inhibition is measured and used for interpretation.
diameter
microbial population
circumference
depth
diameter
What should be the distance of the discs from the edge of the plate?
<10mm
>10mm
<30mm
>30mm
<10mm
What should be the distance of the discs from each other?
<10mm
>10mm
<30mm
>30mm
<30mm
What is the temperature at that antibiotics should be stored in the freezer?
-14 degrees Celsius or less
20 degrees Celsius or less
5 degrees Celsius or less
10 degrees Celsius or less
-14 degrees Celsius or less
Which of the following antibiotics acts as a protein synthesis inhibitor?
Erythromycin, Chloramphenicol
Vancomycin, Cephamycin
Gentamicin, Tetracycline
Options a and c
Erythromycin, Chloramphenicol
Options b and c
Which among the McFarland standards provides turbidity comparable to that of a bacterial suspension containing approximately 1.5 108 CFU/mL?
1.0
1.5
0.5
2.0
1.0
When should antimicrobial susceptibility testing be performed on a bacterial isolate from a clinical specimen?
When the isolate is determined to be a probable cause of the patient’s infection
When the susceptibility of the isolate to particular antimicrobial agents cannot be reliably predicted
a and b (chakto s quizlet)
None of the above
When the isolate is determined to be a probable cause of the patient’s infection
All of the following can lead to false susceptibility results, EXCEPT?
Too dense inoculum
Thin culture medium
Too light inoculum
None of the above
Thin culture medium
