If injection sites are not rotated regularly, the patient with diabetes mellitus may suffer from which of the following?

A. The patient uses OTC drugs prophylactically: OTC (over-the-counter) medications used appropriately shouldn't directly cause microbial repopulation.
B. The patient stops taking the drug when he or she begins to feel better: This is the most concerning habit. Stopping antibiotics early allows susceptible microbes to survive and multiply, potentially leading to a recurrent infection.
C. The patient switches to multiple drug therapy from single drug therapy: This might be done under a doctor's supervision for complex infections, and wouldn't necessarily promote repopulation.
D. The patient increases the drug dosage when he or she perceives that the therapeutic effect is slowing down: Increasing the dosage without consulting a doctor is not recommended, but it wouldn't necessarily cause repopulation if the original dose was effective.

A. Yeast: Yeast allergies are unrelated to cefazolin or other beta-lactam antibiotics.
B. Penicillins: Cefazolin is a cephalosporin antibiotic, and there is a potential for cross-reactivity with penicillins due to their similar beta-lactam ring structure. Checking for a penicillin allergy is essential before administering cefazolin.
C. Macrolides: Macrolides have a different structure and do not cross-react with cephalosporins, so a history of macrolide allergy is not directly relevant.
D. Sulfonamides: Sulfonamides have a different chemical structure, and there is no significant cross-reactivity with cephalosporins.