A novel non-antibiotic treatment approach for chronic and nosocomial infections caused by Staphylococcus aureus biofilms shows promise in offering a way to combat these increasingly difficult-to-treat infections.
A recent study by investigators from the University of Adelaide in Australia showed the efficacy of treating S. aureus biofilms in vitro with two compounds that target the essential iron metabolism for bacterial growth, pathogenesis, and survival. The data was presented at the American Rhinologic Society’s annual meeting in Dallas in September, 2015. [PDF].
“The first compound deferiprone (Def) diverts essential nutrients from bacteria, leaving them vulnerable, while the second compound gallium-protoporphyrin (GaPP) kills them,” said lead investigator of the study, Katharina Richter, a PhD student in the ear, nose, and throat surgery department at The Queen Elizabeth Hospital and Basil Hetzel Institute for Translational Health Research at the University of Adelaide’s, Australia. “The bacteria starve and die,” she said.
The efficacy of this treatment approach was significantly enhanced by delivering the two compounds consecutively versus individually. The study found a 95% efficacy in removing biofilms with consecutive treatment that consisted of two hours of Def (20 mM) followed by two hours of GaPP (200 µg/mL). When delivered individually, biofilm removal was achieved in 35% after DEF monotherapy and 74% after GaPP monotherapy. When delivered together, 55% achieved biofilm removal.
In addition to efficacy, the study found no toxicity to the two cell lines.
According to Richter, additional in vitro studies, including an animal study, not yet published, confirm the efficacy of this treatment approach against MRSA and other bacteria.
A clinical trial is expected to begin later this year that will test a novel drug-delivery-system for clinical use that incorporates this treatment approach.
“This smart medicine approach is envisaged to aid wound healing after sinus surgery and treat biofilm-associated chronic rhinosinusitis topically at the site of infection,” she said, adding that the benefits of this approach are fewer side effects, systemic effects, and interactions with other drugs and food.