USMLE Step 2 Antibiotics and Treatments Practice Exam 2025 - Free Practice Questions and Study Guide

Carbapenems are a class of antibiotics that are primarily effective against Gram-negative bacteria. They are known for their broad spectrum of activity, including coverage of many pathogens that are resistant to other classes of antibiotics. This includes organisms such as Enterobacteriaceae, Pseudomonas aeruginosa, and various other clinically significant pathogens.

The mechanism of action for carbapenems involves inhibiting bacterial cell wall synthesis, similar to other β-lactam antibiotics. Their robust activity against Gram-negative bacteria is particularly noteworthy, especially for strains that produce β-lactamases, as carbapenems are generally resistant to most of these enzymes. This trait makes them valuable in treating serious infections caused by multidrug-resistant Gram-negative organisms.

While carbapenems also have some activity against certain Gram-positive bacteria and anaerobes, their primary and most critical role in clinical practice is as a treatment option for challenging Gram-negative infections. Thus, their spectrum of activity places them chiefly in the realm of treating infections caused by Gram-negative pathogens.