NBRC Pharmacology Practice Exam

The correct choice for the treatment of patients who are resistant to penicillin involves using Nafcillin, Oxacillin, or Methicillin. These antibiotics belong to the class of penicillinase-resistant penicillins, specifically designed to combat bacterial strains that produce the enzyme penicillinase, which can inactivate standard penicillins.

When infections are caused by Staphylococcus aureus or other bacteria that have developed resistance to regular penicillin, these penicillinase-resistant options are effective because they are less susceptible to being broken down by the antibiotic resistance mechanism of the bacteria.

In contrast, the other options involve antibiotics that are not specifically aimed at addressing penicillin resistance. Erythromycin and Keflex, for instance, are not as effective against all penicillase-producing organisms. Similarly, the fluoroquinolones Ciprofloxacin and Levofloxacin, while broad-spectrum, are not the first choice for treating infections where penicillin resistance is a major concern. Tetracycline and Doxycycline are also broad-spectrum antibiotics but do not have the necessary potency against specific resistant strains that the penicillinase-resistant penicillins can target effectively.

Thus, when treating penicillin-resistant infections, using Nafc