Naturally occurring fatty acid may help in the fight in common MRSA bacterial infections
Every year, antibiotic-resistant Staphylococcus aureus, commonly known as “staph,” causes serious infections and outbreaks in hospitals and community settings, disproportionately affecting vulnerable populations, including the elderly and those with weakened immune systems. Methicillin-resistant strains, known as MRSA, are a leading contributor to deaths associated with antimicrobial resistance globally.
Rather than searching for antibiotics that inhibit the growth of bacteria such as MRSA, researchers from the Department of Molecular and Cellular Biology at the University of Guelph, took a different approach, detailed in a new paper in Nature Communications.
The team led by Dr. Georgina Cox, Canada Research Chair in Antimicrobial Resistance, and recent PhD graduate Dr. Allison Leonard, looked for “anti-adhesives,” compounds that can disarm the bacteria by preventing them from sticking to and spreading within our bodies.
“Antibiotics exert strong killing pressure, selecting for resistant bacteria,” says Cox. “But anti-adhesives aim to disarm the bacteria instead of killing them. And because they would be expected to exert little to no selective pressure outside of the host, they may be especially effective at limiting resistance development in the environment, compared to traditional antibiotics. Nevertheless, we need to delve deeper into this phenomenon.”
“Bacteria are so innovative in the ways in which they resist that we have to also be innovative in the strategies to control them.”
Anti-adhesives have potential to stop MRSA
Using a new high-throughput screening technique developed in Cox’s lab and facilities at McMaster University’s Centre for Microbial Chemical Biology, researchers were able to efficiently test nearly 4,000 bioactive compounds, including drugs and natural products, for their ability to prevent staph from binding.
They discovered that geranylgeranoic acid (GGA) – a naturally occurring fatty acid found in plants like ginger and turmeric – interferes with the bacteria’s virulence, its ability to infect, spread, defend itself, and cause disease.
GGA not only made it harder for the bacteria to stick to human molecules—such as proteins found on our skin and in the bloodstream—but also interfered with the bugs’ “sensing” system. By disrupting this sensory ability, the compound effectively disarmed the bacteria, preventing them from detecting and responding to their environment.
“Staph has a diverse arsenal of surface proteins that make it sticky,” says Cox, “but this compound interferes with several of them.”
With researchers at Western University, they then tested the compound on mice, finding that it both prevented the development of skin lesions caused by staph and reduced the severity of existing infections.
Fatty acid found in ginger, turmeric
Anti-adhesives are a bourgeoning research area in the search for potential treatment options for antibiotic-resistant bacterial infections. Similar research from the U.S., now undergoing clinical trials, is exploring the use of mannoside-type blockers — compounds that mimic the binding process E. coli relies on to cling to the urinary tract, preventing infection without antibiotics.”
“Anti-adhesives have a lot of potential, and we really must start thinking of more unusual approaches to control bacteria than just simply going after growth,” says Cox. “I don’t think they would ever replace classic antibiotics, but it’s only a good thing to have alternatives to help as well.”
Future research will further evaluate the efficacy of GGA in animal models, but Cox is also interested in studying other fatty acids, such as oleic acid, found in olive oil, which has similar properties to GGA, and the role of diet more generally in potentially fighting or preventing bacterial infections.
“GGA is a naturally occurring fatty acid from turmeric and ginger, which you already think of when you’re sick, like when you drink hot ginger lemon tea or eat curry to clear your sinuses,” says Ruina Bao, a PhD student in Cox’s lab who contributed to the research.
Researchers caution that eating ginger and turmeric is not a substitute for medical treatment, and more research is needed to determine the effectiveness of GGA and the therapeutic dose.
This study was funded in part by a Canadian Institutes of Health Research grant and the Canadian Foundation for Innovation.