Using penicillin along with modern antibiotics may help weaken methicillin-resistant Staphylococcus aureus and make it easier to cure, a new study shows.

A team of investigators at the National University of Ireland – Galway and the University of Liverpool tested the treatment on 60 patients with MRSA. They found that doubling up the drugs helped reduce the duration of the infection from 3 days to 1.9 days.

They believe the success is due to penicillin’s ability to reduce the virulence of MRSA, which has developed a resistance to many modern-day antibiotics. Once MRSA is weakened, the body’s immune system can “take advantage of this compromised state to destroy the bacteria,” said lead researcher James O’Gara, Ph.D.

“Now we have the key laboratory data that help explain why the combination of two antibiotics is better than one,” O’Gara said. “The beauty of this approach is that penicillin-type antibiotics are not only widely available and safe, but can potentially and more easily be included in clinical practice without the need for long and expensive clinical trials needed for new drugs.”

Findings were published in the Journal of Infectious Diseases on Tuesday.