The world is battling an antibiotic resistance crisis but medical researchers might have just found a potent weapon against the problem. A new iteration of the drug vancomyin that is being called vancomycin 3.0 has been developed that might be 25,000 stronger than its predecessors. Vancomycin has been used to treat infections of caused by common and dangerous bacteria like enterococci and Staphylococcus aureus.

Vancomycin has been used as a drug of last resort since the late 1950s. It defeats bacteria by binding to protein units called peptides that make up the bacterial wall and prevent the cell wall from getting built.The drug binds especially to those peptides that end with the amino acid D-alanine. The bacterial mechanism to overcome this antibiotic action was to replace its peptides ending with D-alanine with peptides ending with D-lactic acid. This reduced vancomycin’s ability to bind to the peptide and rendered the drug ineffective.

Researchers at the Scripps Research Institute in San Diego, California, then improved on the original vancomycin to allow it to bind to peptides ending with both D-alanine and D-lactic acid and developed vancomycin 2.0 in 2011. Now the research team has gone a step further and improved the drug to not only prevent bacterial cell wall building but to also cause leaks in the membrane that lead to cell death. The researchers, work was published in the journal Proceedings of the National Academy of Sciences, report that the antibiotic retains it potency even after being administered for 50 rounds. Most antibiotics become ineffective as bacteria develop resistance to them after only a few rounds.

The researchers told Science that vancomycin 3.0 is not ready for human trials yet. The team would like to cut down on the number of steps used to make the drug and test it on animals first.