Antimicrobial Drugs & Resistance – Chapter 14 OpenStax

26 question-and-answer flashcards covering antimicrobial classifications, mechanisms, resistance, testing, and clinical considerations.

How would you classify a natural antibiotic that has been chemically modified?

Semisynthetic

Which antimicrobial drug is fully synthetic rather than naturally produced?

Sulfanilamide

Which clinical situation most commonly leads to a superinfection?

Long-term use of broad-spectrum antimicrobials

What is the most appropriate and convenient route for at-home antimicrobial administration?

Oral

When is using a narrow-spectrum drug most appropriate?

Treating strep throat caused by culture-identified Streptococcus pyogenes

What term describes a drug’s ability to harm microbes without harming the host?

Selective toxicity

Which group of antibiotics is NOT a β-lactam?

Glycopeptides (e.g., vancomycin)

Which antibiotic does NOT bind to the 50S ribosomal subunit?

Tetracyclines

Which antimicrobial drug inhibits the bacterial enzyme DNA gyrase?

Nalidixic acid

Which molecule would be an inappropriate target for an antifungal drug?

Cholesterol

Which drug class inhibits neuronal transmission in helminths?

Avermectins

Which antiviral medication is a reverse transcriptase inhibitor used against HIV?

Azidothymidine (AZT)

Which antimalarial drug works by increasing reactive oxygen species in parasite cells?

Artemisinin

What is the function of the enzyme β-lactamase in resistant bacteria?

Drug inactivation of β-lactam antibiotics

Which resistance mechanism can protect a bacterium from many unrelated drug classes?

Efflux pump

Which bacterial resistance mechanism is considered the most nonspecific?

Efflux pump

Which drug-resistant bacterium is usually NOT part of the normal gut microbiota?

MRSA (Methicillin-resistant Staphylococcus aureus)

In the Kirby–Bauer disk diffusion assay, what measurement is taken to assess susceptibility?

Diameter of the zone of inhibition

Which common susceptibility test cannot determine the minimum inhibitory concentration (MIC)?

Kirby–Bauer disk diffusion test

For what purpose is an antibiogram most useful?

Guiding empirical therapy in a localized population

From which natural source are most antibiotic compounds originally obtained?

Soil microorganisms (e.g., Streptomyces)

True or False: Narrow-spectrum antimicrobials are commonly used for prophylaxis after surgery.

False – broad-spectrum drugs are more commonly used

True or False: β-lactamases can degrade vancomycin.

False – β-lactamases target β-lactam antibiotics, not glycopeptides like vancomycin

True or False: Echinocandins target β(1→3) glucan in fungal cell walls and are nicknamed “penicillin for fungi.”

True

True or False: A larger zone of inhibition in a Kirby–Bauer test automatically means the drug should be prescribed.

False – other clinical factors and break-point charts must be considered

True or False: The rate of discovery of new antimicrobial drugs has significantly decreased in recent decades.

True