Question 1

Which generation of penicillins has shown beta-lactamase resistance?

Accepted Answer

A subgroup of first-generation penicillins is resistant to penicillinase and is indicated primarily for the treatment of resistant staphylococcal (staph) infections. Staph infections are often difficult to treat because there is a high incidence of bacterial resistance due to penicillinase production among staph bacteria.

Question 2

Which one of the following reactions requires emergency medical attention?

Accepted Answer

A very serious type of skin condition, Stevens-Johnson syndrome, produces a skin reaction that can be fatal. Patients who develop any rash after ingestion of the sulfonamides must receive medical evaluation.

Question 3

Certain bacteria are resistant to the antibiotic penicillin.This can be attributed to:

Accepted Answer

Certain bacteria have the ability to produce enzymes that inactivate penicillin and cephalosporin antibiotics. These enzymes are referred to generally as beta-lactamases. Resistant bacteria are able to produce enzymes, beta-lactamases, that break open the beta-lactam ring.

Question 4

An antibiotic will have no effect on an infection if:

Accepted Answer

Each antibacterial drug is generally effective for only a limited number of pathogenic bacteria. These susceptible bacteria make up the antibacterial spectrum for that particular drug.

Question 5

Identify the antibiotics/families of antibiotics in which nephrotoxicity is a major concern.

Accepted Answer

The first-generation cephalosporins may cause nephrotoxicity, especially in patients with renal impairment or in patients who are dehydrated. When administered parenterally, the two most serious adverse effects of the aminoglycosides are nephrotoxicity and ototoxicity.

Question 6

Why is methicillin no longer used for treating patients with resistant staphylococcal infections?

Accepted Answer

Methicillin is a penicillin that in the past was the most effective penicillin against resistant staphylococcal infections. Because of its toxicity, methicillin is no longer available.

Question 7

A person experiencing a delayed allergic reaction to a penicillin would most likely be switched to a(n)_____.

Accepted Answer

Cephalosporins can be used in patients who are allergic to penicillins.

Question 8

Which of the following are two of the simplest methods used to determine antibiotic susceptibility?

Accepted Answer

Identification of the antibiotics that are effective against specific bacteria is referred to as antibiotic susceptibility. Two of the simplest methods to determine antibiotic susceptibility are the disk test and serial dilution.

Question 9

Meningitis can be effectively treated with:

Accepted Answer

Third-generation cephalosporins are more lipid soluble and cross the blood-brain barrier more readily than most other penicillins and cephalosporins. Consequently, they are often used for both gram-positive and gram-negative infections involving the brain (meningitis).

Question 10

Which of the following are the two dyes that the gram stain contains?

Accepted Answer

One of the most important bacteriological stains is the gram stain, which contains two dyes: crystal violet (purple) and safranin (red). Bacteria that retain only the purple stain are classified as gram positive, whereas bacteria that retain only the red stain are gram negative.

Question 11

A person taking a diuretic and rifampin together should be aware of:

Accepted Answer

Rifampin is taken orally, undergoes enterohepatic cycling, and induces drug-metabolizing enzymes. Rifampin also stains urine, tears (contact lens), and other body fluids orange-red.

Question 12

What type of antibiotic action inhibits the reproduction of bacteria?

Accepted Answer

Antibacterial agents are divided into two main types: bactericidal and bacteriostatic. Bactericidal drugs are lethal; that is, they actually kill the bacteria. Bacteriostatic drugs inhibit the reproduction (growth) of bacteria.

Question 13

Which antibiotics can be used for bowel sterilization prior to surgery?

Accepted Answer

The aminoglycosides are poorly absorbed from the GI tract, and this effect is used to advantage before intestinal surgery. Large doses are given orally before abdominal surgery to reduce the number of intestinal bacteria and sterilize the bowel. In addition, because of their poor oral absorption, some sulfonamides are used to reduce intestinal bacteria before intestinal surgery.

Question 14

A decrease in rifampin effectiveness when taken with other medications may be due to:

Accepted Answer

Rifampin is taken orally, undergoes enterohepatic cycling, and induces drug-metabolizing enzymes. This leads to a decrease in the duration of action of both itself and other drugs and may require an increase in drug dosage.

Question 15

With which antibiotics should alcohol consumption be avoided?

Accepted Answer

Cephalosporins that possess the N-methylthiotetrazone side chain (cefamandole, cefoperazone, cefotetan, others) may interfere with blood coagulation and cause bleeding problems. In addition, these same drugs can cause a disulfiram reaction when combined with alcohol, and patients must be warned to avoid any alcohol consumption when taking these drugs. When mixed with alcohol, metronidazole may cause a disulfiram-like reaction.

Question 16

Which antibiotics can cause photosensitivity as a reaction?

Accepted Answer

The tetracyclines produce photosensitivity in some individuals. The sulfonamides also may produce allergic reactions, which usually are limited to the skin and mucous membranes. The most common reactions include rashes, pruritis, and photosensitivity.

Question 17

What should be done if a patient on vancomycin exhibits a flushing redness of the neck and upper body?

Accepted Answer

A condition known as "red man syndrome" may occur when IV administration of vancomycin is too rapid. There is a flushing redness of the neck and upper body due to histamine release.

Question 18

Which of the following is an ideal candidate for chemoprophylaxis?

Accepted Answer

Chemoprophylaxis refers to the use of antibiotics before bacterial infection has developed in order to prevent infection. Individuals who have had rheumatic fever, heart valve replacement, knee and hip replacement, and other conditions are particularly susceptible to infections that can cause endocarditis and heart valve damage. These individuals should receive chemoprophylaxis before dental, respiratory, urinary, and other invasive medical procedures.

Question 19

Aminoglycosides can produce a synergistic bactericidal action when combined with _____.

Accepted Answer

Aminoglycosides have some gram-positive activity and are often administered in combination with one of the penicillins or cephalosporins in the treatment of serious gram-positive and gram-negative infections. The combination produces a synergistic bactericidal action.

Question 20

Which of the following first-line drugs used to treat tuberculosis must be given by injection?

Accepted Answer

The first-line drugs for treating tuberculosis are isoniazid, rifampin, ethambutol, pyrazinamide, and streptomycin. Streptomycin is one of the aminoglycosides; it is sometimes used in initial therapy for the first few weeks. The major disadvantage is that it requires parenteral administration.

Quiz 41: End of Chapter Questions