Activity of the streptogramin antibiotic etamycin against methicillin-resistant Staphylococcus aureus.

Abstract

The alarming rise of hospital- and community-associated methicillin-resistant Staphylococcus aureus (HA- and CA-MRSA) infections has prompted a desperate search for novel antibiotics. We discovered the streptogramin etamycin produced by an actinomycete species isolated from the coast of Fiji, the first time this antibiotic has been identified from a marine microbe. Etamycin was extracted and purified from this strain (CNS-575) and identified as a three-rotamer species by 2D NMR spectroscopy. Etamycin demonstrated potent activity against HA- and CA-MRSA in microbroth dilution assays, with minimum inhibitory concentrations (MIC) as low as 1-2 mg l(-1) against HA- and CA-MRSA strains. Furthermore, etamycin was also active against other Gram-positive and several Gram-negative pathogens and was found to be non-cytotoxic at concentrations more than 20-fold above MIC. Etamycin displayed favorable time-kill kinetics compared with the first-line MRSA antibiotic, vancomycin, and also conferred significant protection from mortality in a murine model of systemic lethal MRSA infection. These data emphasize the utility of the marine environment as a relatively untapped source of antibiotics against major drug-resistant human pathogens. These studies will also guide future isolation and preclinical development of depsipeptide anti-MRSA compounds from marine-derived actinomycetes.

• Authors: Nina M Haste, Varahenage R Perera, Katherine N Maloney, Dan N Tran, Paul Jensen, William Fenical, Victor Nizet, Mary E Hensler
• Journal: The Journal of antibiotics (J Antibiot (Tokyo)) Vol. 63 Issue 5 Pg. 219-24 (May 2010) ISSN: 1881-1469 [Electronic] England
• PMID: 20339399 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Anti-Bacterial Agents
• Macrolides
• etamycin

Topics

• Actinobacteria (metabolism)
• Animals
• Anti-Bacterial Agents (chemistry, isolation & purification, pharmacology, therapeutic use)
• Female
• Macrolides (chemistry, isolation & purification, pharmacology, therapeutic use)
• Magnetic Resonance Spectroscopy
• Methicillin-Resistant Staphylococcus aureus (drug effects)
• Mice
• Microbial Sensitivity Tests
• Staphylococcal Infections (drug therapy)