American Board of Internal Medicine (ABIM) Certification Practice Exam

Which class of antibiotics is recommended for treating bacteremia due to its excellent bioavailability?

1. Penicillins

2. Cephalosporins

3. Quinolones

4. Tetracyclines

The correct answer is: Quinolones

Quinolones, also known as fluoroquinolones, are a class of antibiotics that are particularly noted for their excellent bioavailability, which refers to the proportion of a drug that enters circulation when it is introduced into the body and is made available for use or storage. This characteristic is crucial when treating conditions like bacteremia, where effective systemic exposure is essential to combat the infection. The bioavailability of quinolones is notably high after oral administration, often surpassing that of many other antibiotic classes. This allows for effective outpatient treatment options, minimizing the need for intravenous administration in some cases. Additionally, quinolones have broad-spectrum activity against both Gram-negative and Gram-positive bacteria, making them suitable for treating a wide range of infections, including those caused by organisms commonly implicated in bacteremia. The other antibiotic classes mentioned, while effective for certain infections, do not typically match the excellent bioavailability of quinolones. For example, penicillins may have variable oral bioavailability depending on the specific drug, and cephalosporins can also show similar limitations. Tetracyclines can have reasonable bioavailability but are often not the first line in the treatment of bacteremia due to their spectrum and potential side effects. Therefore, the