The race to find new treatments against deadly MRSA has a new contestant in the form of an experimental drug that successfully treated the infections of the drug-resistant bacteria in animals. The compound, called TXA709, also restored the effectiveness of cefdinir - an antibiotic in use for nearly 20 years that had lost its ability to deal with MRSA.
This was the result of a new study led by Rutgers University in Piscataway, NJ, and published in the journal Antimicrobial Agents and Chemotherapy.
Senior author Daniel Pilch, associate professor in pharmacology at Rutgers Robert Wood Johnson Medical School, explains the significance of the finding:
"This is important because even though TXA709 is effective on its own in treating MRSA, combining it with cefdinir - used to treat a wide range of bacterial infections like strep throat, pneumonia, bronchitis and middle ear and sinus infections - makes it even more efficacious, while also significantly reducing the potential for the MRSA bacteria to become resistant in the future."
Methicillin-resistant Staphylococcus aureus (MRSA) infections are responsible for thousands of deaths in American hospitals every year, and they cost the economy billions of dollars.
The threat of these and other drug-resistant pathogens is so great that the World Health Organization (WHO) predicts common infections and minor injuries could become life-threatening because of lack of effective treatments.
According to the WHO, people with MRSA are
Kills MRSA in a way not seen before
In their study, where they test the new compound in infected mice, Prof. Pilch and colleagues find that TXA709 "retains potent bactericidal activity against S. aureus strains resistant to the current standard-of-care drugs vancomycin, daptomycin, and linezolid."
They note that the new drug kills MRSA bacteria in a way not seen in currently used antibiotics. It blocks a protein called FtsZ, without which the bacterium cannot divide and survive.
Other tests showed that the drug demonstrates minimal toxicity to mammal cells, they add.
By combining the new drug with cefdinir, a cephalosporin antibiotic that acts in a similar way to penicillin, the researchers were able to lower the dose of TXA709 needed to eradicate the MRSA infection.
The combination effect is an important finding, they say, because it reduces the potential for adverse side effects that might occur at higher doses.
The team also notes that as both drugs can be taken orally, they could be given in an outpatient setting. This is an advantage as most current treatments against MRSA have to be given intravenously.
"Current standard-of-care drugs for the treatment of MRSA infections are limited. Furthermore, resistance to these drugs is on the rise, and their clinical effectiveness is likely to diminish in the future."
Prof. Daniel Pilch
Phase I trials of the experimental antibiotic are planned for next spring, says the team. These will assess and evaluate its effectiveness in humans.