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Chapter 24. Skin and Soft Tissue Infections

TR is a 29-year-old pregnant patient with a diagnosis of cellulitis. TR has no drug allergies and is not on any other medications. Select the most appropriate antibiotic that may be used to treat TR’s infection.

a. Cefazolin

b. Doxycycline

c. Imipenem-cilastatin

d. Levofloxacin

Answer a is correct. Cefazolin is pregnancy category B and is generally considered safe for use during pregnancy. In addition, cefazolin is active against MSSA and GAS, the two most common causes of cellulitis.

Answer b is incorrect. Doxycycline is classified as pregnancy category D due to harmful risks to the fetus. Doxycycline crosses the placenta to cause discoloration of teeth and may also deposit into long bone to inhibit growth. Other adverse effects have been described as well.

Answer c is incorrect. Imipenem-cilastatin belongs to pregnancy category C, denoting observations of adverse effects in animal studies.

Answer d is incorrect. Levofloxacin belongs to pregnancy category C, denoting observations of adverse effects in animal studies.

RD is an 18-year-old woman who presents to a clinic with cellulitis. The local antibiogram reveals that <1% of S. aureus that were isolated last year were methicillin resistant. The treating physician would like to prescribe an oral antibiotic regimen that covers both S. aureus and GAS. Which of the following regimens is the most appropriate for monotherapy?

a. Amoxicillin

b. Cephalexin

c. Ciprofloxacin

d. Trimethoprim-sulfamethoxazole

Answer b is correct. Cephalexin is a first-line antibiotic regimen for cellulitis. It is active against both methicillin-sensitive S. aureus and GAS. As the local prevalence of MRSA is low and the patient does not have specific history to suggest so, RD does not need a MRSA-active treatment.

Answer a is incorrect. Amoxicillin is active against GAS, but is inactivated by penicillinases that most S. aureus strains produce.

Answer c is incorrect. Ciprofloxacin has very unreliable activity against Gram-positive organisms such as S. aureus and GAS.

Answer d is incorrect. While TMP-SMX has excellent activity against S. aureus (including caMRSA, which is not needed for this patient), it lacks activity against GAS. Therefore, another agent would need to be added to adequately cover both S. aureus and GAS.

What is the brand name of linezolid?

a. Teflaro

b. Tygacil

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