American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the preferred treatment for meningitis in patients with allergies to β-lactams?

1. IV vancomycin plus cefepime

2. IV trimethoprim-sulfamethoxazole instead of ampicillin

3. IV amoxicillin

4. IV ceftriaxone

The correct answer is: IV trimethoprim-sulfamethoxazole instead of ampicillin

In cases of bacterial meningitis, especially in patients who have allergies to β-lactam antibiotics, selecting appropriate treatment is crucial. The correct choice is IV trimethoprim-sulfamethoxazole, which serves as an alternative when ampicillin is needed to cover specific pathogens such as Listeria monocytogenes, particularly in immunocompromised patients or those over 50 years old. Trimethoprim-sulfamethoxazole provides effective coverage against Listeria and can be an appropriate substitute for ampicillin in this context. This is significant for patients with β-lactam allergies since ampicillin is usually part of the standard treatment regimen for meningitis in those populations at risk for infections with Listeria. While options like vancomycin plus cefepime, amoxicillin, and ceftriaxone have their uses in treating meningitis, they may not adequately address the coverage needed against Listeria in patients with β-lactam allergies. Vancomycin is effective against methicillin-resistant Staphylococcus aureus (MRSA), and cefepime provides coverage for gram-negative organisms, but neither addresses the risk of Listeria if the patient cannot tolerate ampicillin. Similarly