Final answer:
The main mechanism of ribosomal resistance to macrolides is mutations in the components of the 50S ribosomal subunit.
Step-by-step explanation:
The main mechanism of ribosomal resistance to macrolides is mutations in the components of the 50S ribosomal subunit.
Erythromycin, a macrolide antibiotic, inhibits protein synthesis by binding to the 50S ribosomal subunit of sensitive microorganisms. Certain resistant microorganisms have mutational changes in components of this subunit, which prevent the drug from binding.