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Macrolide resistance mechanisms in Gram-positive cocci

J C Pechère1

  • 1Department of Microbiology and Genetics, University Medical Centre, 1 Rue Michel Servet, CH-1211, Geneva, Switzerland. pechere@cmu.unige.ch

International Journal of Antimicrobial Agents
|September 28, 2001
PubMed

Insights

Two main antibiotic resistance mechanisms exist in Gram-positive bacteria: erm genes causing high-level resistance and mefE genes enabling low-level macrolide efflux. Azithromycin effectively targets strains with mefE genes.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Pharmacology

Background:

  • Gram-positive bacteria exhibit resistance to macrolide antibiotics through identified genetic mechanisms.
  • Two primary resistance pathways involve ribosomal RNA modification and active antibiotic efflux.

Purpose of the Study:

  • To elucidate the principal mechanisms of macrolide resistance in Gram-positive bacteria.
  • To differentiate the clinical significance and resistance levels associated with specific macrolide resistance genes.

Main Methods:

  • Analysis of genetic determinants of macrolide resistance, specifically erm and mefE genes.
  • Evaluation of bacterial protein synthesis inhibition and antibiotic efflux mechanisms.
  • Assessment of azithromycin efficacy against bacteria harboring mefE genes.

Main Results:

  • The erm gene confers high-level macrolide resistance by altering ribosomal RNA structure, preventing antibiotic binding.
  • The mefE gene mediates low-level macrolide resistance through an efflux mechanism.
  • Azithromycin demonstrated efficacy in eradicating mefE-carrying bacterial strains due to its concentration at infection sites.

Conclusions:

  • Erm-mediated ribosomal modification and mefE-mediated efflux are key macrolide resistance mechanisms in Gram-positive bacteria.
  • Resistance levels vary significantly between these two mechanisms.
  • Azithromycin holds therapeutic potential against specific macrolide-resistant bacterial infections.

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