New drug approach could overcome antibiotic resistance

Researchers have discovered a new group of antibiotics that may provide relief to those affected by antibiotic resistance.
The new antibiotics target the bacteria Staphylococcus aureus, or staph, and the antibiotic resistant strains commonly known as MRSA, short for methicillin-resistant Staphylococcus aureus.
In 2013, invasive MRSA infections were responsible for an estimated 9,937 deaths in the US, researchers said.
Although current infection rates are declining, the majority of these deaths, about 8,150, were associated with inpatient stays in health care facilities, according to the Active Bacterial Core surveillance report by the Centres for Disease Control and Prevention in US.
The discovery shows that the potential new antibiotics are unlike contemporary antibiotics because they contain iridium, a silvery-white transition metal.

New 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, further testing by the researchers shows that they are nontoxic to animals and animal cells.
"So far our findings show that these compounds are safer than other compounds made from transition metals," said corresponding author Joseph Merola, a professor at the Virginia Institute of Technology.
"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," Merola said.

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.
"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," said Joseph Falkinham, a professor of microbiology in the College of Science and an affiliate of the Virginia Tech Centre for Drug Discovery.
The team is currently testing the compounds in human cell lines and, so far, the cells have remained normal and healthy.

The study was published in the journal Medicinal Chemistry Communications.