Principles of antimicrobial therapy

Question 1

H. influenzae’s primary mechanism of antimicrobial resistance is via:

Answer 1

Beta-lactamase production.

Question 2

The decision-making process where a clinician chooses an agent based on patient characteristics and site of infection is called:

Answer 2

Empiric therapy.

Question 3

Which of the following best describes the mechanism of action of beta-lactams?

Answer 3

Disrupt synthesis of the peptidoglycan layer of bacterial cell walls

Question 4

The use of which of the following agents should be avoided in children and pregnant women due to the possibility of teeth staining?

Answer 4

Tetracycline

Question 5

Which of the following characteristics apply to the macrolides?

Answer 5

Effective against atypical pathogens

Question 6

Which of the following best describes the mechanism of action of the macrolides?

Answer 6

Inhibition of bacterial protein biosynthesis

Question 7

Which of the following best describes the mechanism of action of sulfonamides?

Answer 7

Inhibiting folate synthesis

Question 8

An antibiotic described as having bacteriostatic action is capable of:

Answer 8

Inhibiting growth or reproduction of an organism.

Question 9

Which of the following antibiotics exhibits time-dependent pathogen-killing activity?

Answer 9

Penicillin

Question 10

For the minority (<10%) of acute bronchitis cases not caused by virus, the likely causative pathogens include all of the following except:

Answer 10

Haemophilus influenzae.

Question 11

A 35-year-old woman with a sulfa allergy presents with an uncomplicated UTI. She has not received any systemic antimicrobials in more than 6 months. She is currently not pregnant and is using norelgestromin/ethinyl estradiol patch (Ortho Evra®). You recommend treatment with:

Answer 11

Nitrofurantoin.

Question 12

The recommended regimen of fosfomycin for the treatment of uncomplicated UTI in a non-pregnant woman is:

Answer 12

One dose of 3 g.

Question 13

In geographic areas where E. coli resistance to TMP/SMX is >20%, alternative treatments include phenazopyridine plus all of the following except:

Answer 13

Amoxicillin.

Question 14

Which of the following is a first-line therapy for the treatment of acute bacterial rhinosinusitis in a 9-year-old boy with no risk for antimicrobial resistance?

Answer 14

Amoxicillin-clavulanate

Question 15

A 46-year-old man who is currently smoking 1 PPD and has a 30 pack-year cigarette smoking history with penicillin allergy presents with acute bacterial rhinosinusitis. Three weeks ago, he was treated with a macrolide for “bronchitis.” You now prescribe:

Answer 15

Levofloxacin.

Question 16

A 35-year-old woman who is not pregnant was initiated on high-dose amoxicillin 4 days ago to treat acute bacterial rhinosinusitis. She returns complaining of no change in symptoms. You recommend switching her treatment to:

Answer 16

Levofloxacin.

Question 17

A 26-year-old woman presents with uncomplicated UTI. She is otherwise healthy, has not received any systemic antimicrobials in the past year, does not have a sulfa allergy, and is not taking any medications other than Ortho-Cyclen® (ethinyl estradiol and norgestimate) for birth control. Her last menstrual period began 10 days ago. The local E. coli resistance rate to TMP/SMX is about 10%. The preferred therapy for this patient is:

Answer 17

Trimethoprim-sulfamethoxazole.

Question 18

A 13-year-old boy presents with acute bacterial rhinosinusitis. He has a beta-lactam allergy and had taken clarithromycin 2 months ago for a “bad cold.” You recommend treatment with:

Answer 18

Levofloxacin.

Question 19

Risk factors for developing fluoroquinolone-associated tendinitis and tendon rupture include all of the following except:

Answer 19

Recent use of a systemic beta-lactam antimicrobial.

Question 20

All of the following antimicrobials would be expected to exhibit in vitro activity against beta-lactamase-producing Moraxella catarrhalis except:

Answer 20

Amoxicillin