A widely used blood pressure medication could hold the key to tackling one of the world's most dangerous antibiotic-resistant bacteria, according to new research published in the journal Nature Communications.
Scientists at the Houston Methodist Research Institute in Texas have found that a drug called Candesartan cilexetil, commonly prescribed for high blood pressure and heart failure, may be capable of fighting methicillin-resistant Staphylococcus aureus, better known as MRSA. The findings were first reported by ScienceAlert.
In laboratory and animal studies, the drug was found to disrupt the bacteria's cell membrane, interfering with its cellular function and ultimately killing it. Advanced imaging revealed that the medication effectively punched holes in the MRSA membrane, causing the cell's contents to leak out.
Researchers also discovered that Candesartan cilexetil could target dormant MRSA bacteria that lie hidden in the body and resurface later, a trait that makes the superbug particularly difficult to treat. When combined with existing antibiotics such as gentamicin, the drug produced a stronger effect at lower doses than either treatment alone.
Because Candesartan cilexetil is already approved, inexpensive and in widespread use, scientists say it could prove an especially attractive candidate if its effectiveness against MRSA is confirmed in human trials.
"I think that CC is one of the most exciting agents that we have found," senior author Eleftherios Mylokanis told ScienceAlert. Mylokanis, an infectious disease specialist at Houston Methodist Academic Institute, noted that MRSA is among the most frequently encountered resistant pathogens in his clinical practice.
MRSA causes skin, lung and bloodstream infections, resulting in more than 70,000 severe cases and around 9,000 deaths in the United States every year, according to the Centers for Disease Control and Prevention. Globally, antibiotic-resistant microbes were directly responsible for more than 1.27 million deaths in 2019 alone.
Despite the growing urgency, the development of new antibiotics has not kept pace with the threat, partly because such drugs offer limited financial returns for pharmaceutical companies.
"The market is completely upside down," Mylokanis told ScienceAlert. "The better the antibiotic, we try not to use it, because we worry it will develop resistance."
The discovery emerged from an earlier screening exercise in which the team tested more than 80,000 compounds on MRSA-infected worms. Only a small number proved effective, and Candesartan cilexetil was among them. Researchers then spent considerable time building a detailed picture of how the drug interacts with the bacteria, analysing genetic material, lipids and small molecules involved in the process.
"We started building one by one, block by block," first author Nagendran Tharmalingam told ScienceAlert. "We found how this drug is causing membrane injury."
The team is now working to develop chemically modified versions of the drug that may prove even more effective and carry fewer side effects. They are also in early discussions with pharmaceutical and biotech companies to advance human trials.
"We are trying to get this from benchside to bedside," Tharmalingam said.
The research was published in Nature Communications.
