Bio 2421 Chapter 9 Quiz

Choose the statement that correctly explains how an antibiotic that inhibits protein synthesis can be selective.

Antibiotics bind to the 70S bacterial ribosomes but not to the 80S eukaryotic ribosomes.

Identify all the ways that could help slow the emergence and spread of antimicrobial resistance.

Educate patients on the proper use of prescribed drugs (don't skip a dose), Have healthcare workers observe patients taking their antibiotic dose, to ensure compliance with the antibiotic regimen, Administer 2 or 3 drugs simultaneously to prevent the emergence of resistance to one drug, Encourage appropriate administration of drugs (don't over prescribe).

Why are there far fewer antifungal agents than there are antibacterial agents?

Fungal cells are much more similar to human cells than are bacterial cells.

This term is used to describe the lowest concentration of a drug effective at preventing growth of particular microbes.

MIC

Sulfonamides inhibit an enzyme necessary for production of purines and pyrimidines. What long-term impact would it have on a microbe if it were grown in the presence of sulfonamides?

The cell would cease to divide

Identify all possible adverse effects of using antibiotic drugs correctly

allergic reaction, toxic effects at high concentrations, suppression of the normal flora

The class of antimicrobials that would have the most selective toxicity is

antimicrobials that inhibit cell wall synthesis

A key feature of penicillin is the ______ ring.

beta-lactam

Penicillins are a group of antibiotics known for inhibiting _______ synthesis in ______.

cell wall; bacteria

Because of widespread resistance to penicillin, structurally related classes of antibiotics, the ______, were developed.

cephalosporins

Chemotherapeutic agents have different levels of activity and effectiveness, with some being ____ or strong enough to kill microbes while others are only ____, inhibiting microbial growth.

cidal; static

The mechanism of this type of antibiotic is to block the formation of _______ in the complex polymer ______.

cross-links; peptidoglycan

There are several ways to measure these concentrations, including _____ ______ tests where a series of drug concentrations is tested.

dilution susceptibility

Another important method is the ____ ______ assay, where a ring of inhibition is seen around a piece of filter paper containing the antibiotic.

disk diffusion

Finally, the _____ uses a convenient test strip impregnated with increasing concentrations of the antibiotic.

etest

This test is also known as the ____-____ method.

kirby-bauer

The lowest concentration that prevents microbial growth is the _____ _______ concentration, while the lowest level that can kill microbes is the ______ _______ concentration.

minimal inhibitory; minimal lethal

This term is used to describe drugs that are effect against only a limited variety of microbes.

narrow-spectrum drug

This is also its weak point, as penicillin-resistant pathogens contain the enzyme ______ that destroys this ring.

penicillinase

This term is used to describe compounds that cause greater harm to microbes than to the human host.

selective toxicity

The distribution and metabolism of some antimicrobial drugs can be adversely affected by

the inability of specific tissue to absorb the drug, a low speed of uptake by the patient's body, the ability of the host to metabolize the drug quickly