A world-first clinical trial has called into question the effectiveness of using more than one antibiotic to treat methicillin-resistant staphylococcus aureus (MRSA) bacteremia.

Researchers from the University of Queensland, in collaboration with global counterparts, have found using two antibiotics to treat MRSA infection provides no advantage over using a single antibiotic.

The three-year, multi-center study involved 352 patients at 27 hospitals in Australia, Singapore, Israel and New Zealand.

UQ professor David Paterson said researchers tested whether adding a second antibiotic for seven days to a standard antibiotic treatment would lead to improved health outcomes after 90 days.

"We found no significant difference in mortality, bacteria in the blood, infection relapse or treatment failure," Paterson said. "Furthermore, patients who received two antibiotics had a higher rate of side effects related to kidney function than those who received just one antibiotic. For many years doctors have debated whether MRSA should be treated with two antibiotics or just one antibiotic. This trial now puts that debate to rest and will have a huge impact on how antibiotics are used for MRSA infections worldwide. These findings are hugely important on a number of levels -- one of the most important implications of the research is how it can impact antibiotic use and the global issue of antibiotic resistance."

MRSA is a common and very serious cause of infection that affects more than 10,000 people in Australia every year, especially women aged 60 and over.

Treating the infection can take up to several months and requires lab testing for diagnosis.

This study was published in the journal JAMA, DOI:10.1001/jama.2020.0103

Source: University of Queensland