Cefixime is the chemical structure associated with which antibiotic class?

• A. Cephalosporin
• B. Macrolides
• C. Penicillin
• D. Quinolones

Answer: (A)

Antibiotics are grouped by their chemical scaffold, and cefixime is a cephalosporin because its structure contains the cephem nucleus—a beta-lactam ring fused to a dihydrothiazine ring. This cephem framework is the defining feature of cephalosporins, setting them apart from other classes. Macrolides are built around a large macrocyclic lactone, penicillins have a penam nucleus, and quinolones have a quinolone core with fluorination. So the structure of cefixime aligns with cephalosporins, making that the correct class.