WASHINGTON, March 9 (UPI) -- Antibiotics that no longer work against methicillin-resistant Staphylococcus aureus, or MRSA, were found to be effective in mice when paired with two synthetic compounds, according to a new study.
MRSA is resistant to a group of antibiotics call ß-lactam, which includes penicillin and methicillin, but scientists at the Merck Research Laboratory designed two compounds they found make the bacteria susceptible to the drugs.
The Merck scientists are not the first in recent months to find drugs that are effective against the infection, at least in the lab, as one study in 2015 found the breast cancer drug tamoxifen killed MRSA and another found the combination of meropenem, piperacillin and tazobactam killed it.
For the study, published in Science Translational Medicine, the researchers looked for methods of stopping the production of teichoic acid, a component in cell walls that helps the bacteria resist ß-lactam antibiotics.
After identifying the compounds tarocin A and tarocin B as blocking the enzyme key to production of teichoic acid, the researchers found the compound combined with an antibiotic was effective against MRSA. In mice, they found the compound and antibiotic were ineffective alone, but mice lived when given the compounds and antibiotics together.
While more research is needed, the researchers said if the compound works in humans the path to FDA approval is faster because it is not a new drug, adding that the approach to making the group of antibiotics effective again could potentially be used in efforts against other infections.
"It opens up more targets and new chemical space to consider," Terry Roemer, a researcher at Merck, told The Scientist. "You just have to pair it with an existing antibiotic."