The new antibiotics are synthetic forms of cephalosporin, a broad-spectrum antibiotic closely related to penicillin. They appear to kill bacteria by masquerading as components of the bacterial cell wall in order to deactivate an enzyme that functions as a key bacterial defense mechanism, the researchers say. In preliminary lab tests, the new antibiotics - the first to exhibit this mimicry mechanism - were effective against vancomycin-resistant MRSA, a rare but extremely deadly staph strain for which treatment options are extremely limited, they say.

“We are the first to demonstrate this unique strategy, which could provide a new line of defense against the growing problem of antibiotic resistance,” says study leader Shahriar Mobashery, Ph.D., a chemist at the university. “As scientists, we’re trying to stay one step ahead of the bacteria. The more strategies there are to fight resistance, the better.”

Besides fighting staph bacteria, the compounds have the potential to work against a wide range of other types of infectious bacterial strains that appear in health-care and community settings, he says. At least one of the cephalosporin compounds identified has entered Phase I clinical trials, but results are not yet available. More studies are needed before it can be marketed, Mobashery and his associates say.

Based on lab studies, Mobashery believes that the novel antibiotics gained access to the enzyme’s active site by mimicking chemical components of the bacterial cell wall, which is largely composed of a polymer called peptidoglycan. Upon contact with the cell wall components, the antibiotics appear to trigger the enzyme to open. Once open, the antibiotics deactivate the enzyme, setting in motion a chain of events that eventually kills the bacteria, the researcher says.

MEDICA.de; Source: American Chemical Society (ACS)