Virtual Labs

Determination of minimal inhibitory concentration (MIC) of an antibiotic

1. Which of the following factors can influence the determination of the minimal inhibitory concentration (MIC)?

a: Temperature and humidity of the testing environment Explanation

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b: Size of the culture dish used for testing Explanation

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c: Genetic makeup of the host organism Explanation

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d: pH of the growth media Explanation

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2. Which of the following statements is true regarding the minimal inhibitory concentration (MIC)?

a: A lower MIC value indicates higher susceptibility of bacteria to the antibiotic. Explanation

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b: The MIC value is inversely proportional to the antibiotic's effectiveness. Explanation

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c: The MIC value is only relevant for gram-negative bacteria. Explanation

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d: The MIC value is independent of the bacterial species being tested. Explanation

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3. Which method employs gradient strips to determine the minimal inhibitory concentration(MIC) of an antibiotic?

a: Agar dilution method Explanation

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b: Broth dilution method Explanation

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c: E-test method Explanation

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d: Disc diffusion method Explanation

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4. In the disc diffusion test, the size of the zone of inhibition is directly proportional to:

a: The concentration of the antibiotic in the disc Explanation

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b: The bacterial resistance to the antibiotic Explanation

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c: The bacterial growth rate Explanation

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d: The minimal inhibitory concentration (MIC) Explanation

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5. In the broth dilution method, what is the primary purpose of using a series of test tubes or well plates with different concentrations of antibiotics?

a: To measure the optical density of bacterial cultures Explanation

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b: To determine the nutrient requirements for bacterial growth Explanation

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c: To identify the lowest concentration of antibiotic that inhibits bacterial growth Explanation

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d: To compare the effectiveness of different antibiotics Explanation

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6. At what temperature are the test tubes or well plates typically incubated overnight in the broth dilution method?

a: 25 degrees Celsius Explanation

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b: 30 degrees Celsius Explanation

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c: 37 degrees Celsius Explanation

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d: 45 degrees Celsius Explanation

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7. Which of the following best describes the E-strips used in the antimicrobial gradient method?

a: Strips with a uniform concentration of antibiotic Explanation

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b: Strips with a predefined gradient of antibiotic concentrations Explanation

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c: Strips that change color based on bacterial growth Explanation

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d: Strips that are saturated with nutrients for bacterial growth Explanation

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8. How are paper disks prepared for the disk diffusion test?

a: By soaking them in a nutrient broth Explanation

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b: By saturating them with different concentrations of antibiotics Explanation

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c: By sterilizing them with UV light Explanation

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d: By coating them with bacterial cultures Explanation

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9. What is the main advantage of using the broth dilution method?

a: It is the fastest method available Explanation

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b: It allows for high-throughput testing Explanation

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c: It provides precise quantification of the MIC Explanation

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d: It requires the least amount of reagents Explanation

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10. What is a key advantage of the antimicrobial gradient method compared to the broth dilution method?

a: It does not require incubation. Explanation

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b: It provides a quantitative result with a single test. Explanation

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c: It is more suitable for anaerobic bacteria. Explanation

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d: It can be used for fungi as well as bacteria. Explanation

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