Erythromycin-resistance mechanisms

Erythromycin-resistance mechanisms represent a suite of biological strategies employed by bacteria to neutralize the efficacy of erythromycin and other macrolide antibiotics. The most clinically significant mechanism is the modification of the drug binding site on the 50S ribosomal subunit, typically through the methylation of the A2058 residue of the 23S ribosomal RNA by Erm (Erythromycin Ribosome Methylation) enzymes (PubMed: 10547357). This modification sterically hinders the binding of macrolides, lincosamides, and streptogramin B, leading to the MLSB resistance phenotype. Other prevalent mechanisms include the active transport of the antibiotic out of the cell via efflux pumps, such as those encoded by mef or msr genes, and the direct enzymatic degradation of the drug by erythromycin esterases (Ere) or phosphotransferases (StatPearls: Macrolides). These resistance mechanisms are often localized on mobile genetic elements like plasmids or transposons, facilitating rapid dissemination across different bacterial species and contributing to the rise of multidrug-resistant pathogens like Streptococcus pneumoniae and Staphylococcus aureus (NCBI: NBK7617). Consequently, these mechanisms pose a major challenge to the treatment of respiratory and skin infections, necessitating the development of novel antibiotics like ketolides that can overcome specific resistance pathways.

Other names

Macrolide resistanceMLSB resistanceRibosomal methylationMacrolide efflux

Resistance mechanisms function by modifying the ribosomal target site to prevent drug binding, actively transporting the drug out of the cell via efflux pumps, or enzymatically inactivating the antibiotic molecule.