Fig. 4. Mechanisms of resistance against ribosome-targeting antibiotics. (A) To prevent antibiotic entry, drug-resistant bacteria can alter the expression level or pore structure of porins. (B) The expression of efflux pumps facilitates drug extrusion from the cell thereby reducing intracellular drug concentrations. (C) As antibiotics reach the cytoplasm, they may be deactivated by drug-modifying enzymes or (D) degraded in their native form or after modification to enhance degradation. (E) Through the use of ribosome protection proteins (RPP), bacteria can resist inhibition by dislodging antibiotics from their ribosomal binding site. Resistant bacteria can also alter the drug target site via (F) mutation of residues critical for drug-binding or (G) chemical modification of target residues. Drug or target site chemical modification reduces binding affinity due to steric clash and/or electrostatic repulsion. Created with https://BioRender.com.