The developments could eradicate the threat of antibiotic-resistant infections for many years.

1,000-fold increase in activity of existing drug, vancomycin

Researchers at The Scripps Research Institute (TSRI) have structurally modified powerful antibiotic, vancomycin, to create a far stronger version of the drug.

The developments - led by Dale Boger and Akinori Okano, senior and first authors of the study at TSRI - could eradicate the threat of antibiotic-resistant infections for many years.

Vancomycin, an antibiotic that has been used for 60 years, presents a “mechanism of action” that bacteria have found difficult to overcome, up until now. This “mechanism” involves disrupting the process through which bacteria form cell walls, presenting a platform upon which new antibiotics can be developed.

In past studies, the team of TSRI scientists recognised the possibility of adding two modifications to vancomycin, to make it even more potent. Now, scientists have made a third modification that effects the bacterium cell wall in an additional way.

The three collective modifications give vancomycin a 1,000-fold amplification in activity, meaning less would be needed to treat infections. The modifications make vancomycin the first antibiotic to have three independent mechanisms of action.

Boger commented: “This increases the durability of this antibiotic. Organisms just can’t simultaneously work to find a way around three independent mechanisms of action. Even if they found a solution to one of those, the organisms would still be killed by the other two.”

When tested against Enterococci bacteria, the new version of vancomycin killed the resistant form of Enterococci, as well as the original forms of the bacteria. Scientists now need to develop a way to synthesise the new form of the antibiotic using a shorter laboratory process. The current method contains 30 different steps, however, Boger considers this the “easy part”, following the challenge of designing an effective molecule, in the first place.

Boger stated: “Antibiotics are total cures for bacterial infections. Making this molecule is important, even by the current approach, if the failure of antibiotics continues.”

Fellow authors, Akinori Okano and Nicholas A. Isley, said: “Peripheral modifications of vancomycin with added synergistic mechanisms of action provide durable and potent antibiotics.”

The breakthrough study was supported by the National Institutes of Health.