Extended-spectrum beta-lactamases confer resistance to which antibiotic among the following?

Extended-spectrum beta-lactamases confer resistance to which antibiotic among the following?

• A. Rifampin
• B. Amoxicillin
• C. Erythromycin
• D. Ceftriaxone

Answer: (D)

Extended-spectrum beta-lactamases break down beta-lactam antibiotics, especially the expanded-spectrum cephalosporins. Ceftriaxone is a third-generation cephalosporin, so bacteria producing ESBLs commonly show resistance to it. Rifampin and erythromycin aren’t beta-lactams, so ESBLs don’t explain resistance to those. Amoxicillin is a beta-lactam penicillin, which can be inactivated by beta-lactamases as well, but the hallmark and most clinically relevant resistance pattern for ESBL producers is failure of third-generation cephalosporins like ceftriaxone, making it the best answer.

Extended-spectrum beta-lactamases break down beta-lactam antibiotics, especially the expanded-spectrum cephalosporins. Ceftriaxone is a third-generation cephalosporin, so bacteria producing ESBLs commonly show resistance to it. Rifampin and erythromycin aren’t beta-lactams, so ESBLs don’t explain resistance to those. Amoxicillin is a beta-lactam penicillin, which can be inactivated by beta-lactamases as well, but the hallmark and most clinically relevant resistance pattern for ESBL producers is failure of third-generation cephalosporins like ceftriaxone, making it the best answer.