Old and new antibiotics joining forces against vancomycin-resistant enterococci

What is it about?

Vancomycin-resistant Enterococcus faecium (VRE) is a hospital superbug listed by the WHO as a high priority, and treatment options are few. Linezolid, the main oral option, can be toxic and resistance is emerging. New drugs of the same family (oxazolidinones) - contezolid, delpazolid and sutezolid - may be safer. We tested in the laboratory whether combining them with fosfomycin, an old antibiotic, works better than each drug alone against 10 VRE strains from bloodstream infections. All combinations showed synergy (the drugs boosted each other), most consistently fosfomycin plus delpazolid. The combinations lowered the amount of fosfomycin needed to stop bacterial growth by up to 16 times, and time-kill experiments confirmed a stronger killing effect after 24 hours.

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Photo by Trnava University on Unsplash

Photo by Trnava University on Unsplash

Why is it important?

This is the first study to test fosfomycin together with the newer oxazolidinones against VRE. Since these new drugs appear less toxic than linezolid, pairing them with fosfomycin could become a safer and more effective strategy for difficult VRE infections. The results provide the preclinical rationale for animal studies and clinical trials.

Perspectives