Which antibiotic is a macrolide?

Which antibiotic is a macrolide?

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

Answer: (A)

Macrolides inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit and blocking the translocation step, which stops the growing peptide chain. Erythromycin is the classic example of a macrolide, illustrating this mechanism. This class is typically effective against many Gram-positive cocci and atypical pathogens such as Mycoplasma and Legionella, making it a common choice for respiratory infections. Clindamycin also targets the 50S subunit but is a lincosamide, not a macrolide. Amoxicillin and ceftriaxone are beta-lactams that inhibit cell wall synthesis, not protein synthesis, so they are not macrolides.

Macrolides inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit and blocking the translocation step, which stops the growing peptide chain. Erythromycin is the classic example of a macrolide, illustrating this mechanism. This class is typically effective against many Gram-positive cocci and atypical pathogens such as Mycoplasma and Legionella, making it a common choice for respiratory infections. Clindamycin also targets the 50S subunit but is a lincosamide, not a macrolide. Amoxicillin and ceftriaxone are beta-lactams that inhibit cell wall synthesis, not protein synthesis, so they are not macrolides.