Scientists are constantly looking for new weapons in the battle against antibiotic-resistant bacteria, and a team of researcher from Virginia Tech has announced the discovery of a new group of antibiotics shown to be effective against methicillin-resistant Staphylococcus aureus, or MRSA.
According to the team’s report, published in Medicinal Chemistry Communications, the prospective new antibiotics are not like current antibiotics because they include iridium, a silvery-white transition metal. New transition metal complexes do not quickly degrade, which is critical for transport of antibiotics to infected locations in the body.
In the study, testing revealed that the iridium compounds are not toxic to animals and animal cells, which led researchers to say they are probably safe for human use.
“So far our findings show that these compounds are safer than other compounds made from transition metals,” said Joseph Merola, a professor of chemistry at Virginia Tech. “One of the reasons for this is that the compounds in this paper that target MRSA are very specific, meaning that a specific structure-function relationship must be met in order to kill the bacteria.”
The antibiotics efficiently kill the bacteria without suppressing mammalian cells, and a form of the antibiotic was tested for toxicity in mice with no observed harmful effects.
“We are still at the beginning of developing and testing these antibiotics but, so far, our preliminary results show a new group of antibiotics that are effective and safe,” said Joseph Falkinham, a professor of microbiology at Virginia Tech. “Within the next few years, we hope to identify various characteristics of these antibiotics, such as their stability, their distribution and concentration in animal tissue, their penetration into white blood cells, and their metabolism in animals.”
Bacteria have not evolved to resist these
“The biggest question scientists have to ask to tackle antibiotic resistance is, how can we stay on top of the bacteria? Fortunately, these new organometallic antibiotics are coming at a time when bacteria have not evolved to resist them,” Merola added.
In another development, a team of American researchers has just announced the successful testing of a three antibiotics in combination against MRSA that aren’t successful individually against the resistant bacterium.
According to the team’s report, published in the journal Nature Chemical Biology, a combination of meropenem, piperacillin, and tazobactam was shown to be effective against MRSA.
“Without treatment, these MRSA-infected mice tend to live less than a day, but the three-drug combination cured the mice,” study author Gautam Dantas, an associate professor of pathology and immunology, said in a news release. “After the treatment, the mice were thriving.”
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