The ribosome is a major bacterial target for antibiotics. Drugs inhibit ribosome function either by interfering in messenger RNA translation or by blocking the formation of peptide bonds at the peptidyl transferase centre. These effects are the consequence of the binding of drugs to the ribosomal subunits. Various mechanisms, including enzymatic detoxification, target alteration (ribosomal [r]RNAs and ribosomal proteins) and reduced accumulation (impermeability and efflux) are involved in bacterial resistance to protein synthesis inhibitors. The fact that some positions in rRNA participate in the binding of antibiotics belonging to distinct families explains why bacteria have developed mechanisms that can lead to cross-resistance.
