Researchers discover new group of antibiotics

Researchers have discovered a new group of antibiotics that target the bacteria Staphylococcus aureus and the antibiotic resistant strains commonly known as MRSA (methicillin-resistant Staphylococcus aureus).

The potential new antibiotics are unlike contemporary antibiotics because they contain iridium, a silvery-white transition metal. Transition metal complexes do not easily breakdown, which is important for delivery of antibiotics to where they are needed to fight infections in the body.

Even though these compounds contain iridium, testing by the Virginia Tech researchers shows that they are nontoxic to animals and animal cells. Thus, they are likely safe for use in humans, according to the researchers.

“So far our findings show that these compounds are safer than other compounds made from transition metals,” said Joseph Merola, a professor of chemistry in the College of Science, a Fralin Life Science Institute affiliate. “One of the reasons for this is that the compounds…that target MRSA are very specific, meaning that a specific structure-function relationship must be met in order to kill the bacteria.”

Researchers showed the antibiotics effectively kill the bacteria without inhibiting mammalian cells. A version of the antibiotic was tested for toxicity in mice with no ill effects.

Researchers continue to investigate the new antibiotics

“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 in the College of Science and an affiliate of the Virginia Tech Centre for Drug Discovery. “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.”

The team is currently testing the compounds in human cell lines and, so far, the cells have remained normal and healthy.

This discovery comes at a time when antibiotic resistance is a significant health concern all over the world, for people and for livestock.

“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,” said Merola, who is also an affiliate of the Virginia Tech Centre for Drug Discovery.