Understanding Bacteroides fragilis and Antibiotic Combinations

Which of the following antibiotics is NOT a beta-lactam/beta-lactamase inhibitor combination used for Bacteroides fragilis?

• A. Metronidazole
• B. Beta-lactam/Beta-lactamase inhibitor
• C. Ceftaz/avibactam
• D. Cefotetan

Answer: (C)

Ceftazidime/avibactam is not a beta-lactam/beta-lactamase inhibitor combination used for Bacteroides fragilis. It is a combination of a beta-lactam (ceftazidime) and a beta-lactamase inhibitor (avibactam), but it is not effective against Bacteroides fragilis. Metronidazole, on the other hand, is an effective antibiotic for Bacteroides fragilis and is not a beta-lactam or beta-lactamase inhibitor. Similarly, cefotetan is a standalone beta-lactam antibiotic and does not contain a beta-lactamase inhibitor. Therefore, neither of these options are the correct answer to the question. Only ceftazidime/avibactam is not a beta-lactam/beta-lactamase inhibitor combination used for Bacteroides fragilis.

When you’re knee-deep in your studies for the NAPLEX, it’s crucial to get your head wrapped around the specifics of antibiotics. Take, for instance, a common question: Which antibiotic isn’t a beta-lactam/beta-lactamase inhibitor combination effective against Bacteroides fragilis? The answer to that is Ceftazidime/avibactam. Now, don't worry if that sounds a bit dense; stick with me as we flesh this out.