Which statement best contrasts ESBL-producing Enterobacterales and carbapenemase producers?

• A. Carbapenemases only hydrolyze penicillins.
• B. ESBLs hydrolyze penicillins and cephalosporins; carbapenemases hydrolyze most beta-lactams; ESBLs are typically treated with carbapenems; carbapenemases may require newer agents or combinations (e.g., ceftazidime-avibactam, meropenem-vaborbactam).
• C. ESBLs are more active against carbapenems than penicillins.
• D. ESBLs are unaffected by any beta-lactam antibiotics.

Answer: (B)

The key idea is understanding how these enzymes differ in what they break down and how that shapes treatment. ESBLs expand the range of beta-lactams they hydrolyze to include penicillins and cephalosporins, which makes many common options unreliable. Carbapenemases have a broader, more dangerous activity: they can break down almost all beta-lactams, including carbapenems, which limits effective drugs and often pushes use toward newer agents or specific combinations.

That’s why the best choice correctly states that ESBLs hydrolyze penicillins and cephalosporins, while carbapenemases hydrolyze most beta-lactams. It also reflects the practical treatment implications: infections with ESBL producers are typically treated with a carbapenem, whereas carbapenemase producers may require newer agents or combinations (for example, ceftazidime-avibactam or meropenem-vaboractam) to achieve activity.

The other options misstate the scope of these enzymes: for example, one claims carbapenemases only affect penicillins, which is untrue since they inactivate a broad range including carbapenems; another suggests ESBLs are more active against carbapenems, which is the opposite of reality; and another says ESBLs are unaffected by beta-lactams, which contradicts their very definition as beta-lactamases.