The world is facing the threat of ‘superbugs’ as these bacteria dubbed as methicillin-resistant Staphylococcus aureus (MRSA) have evolved into one of the most difficult-to-treat pathogens. MRSA is a bacteria that is resistant to many antibiotics. In the external community, most MRSA infections are skin infections. In medical facilities, MRSA causes life-threatening bloodstream infections, pneumonia and surgical site infections.
A new study suggests that treatment with the wrong antibiotic could make MRSA-induced infections worse. Researchers at Cedars-Sinai Medical Center in Los Angeles say mice infected with methicillin-resistant Staphylococcus aureus (MRSA) actually became sicker when they were treated with beta-lactam antibiotics. The findings were published in the journal Cell Host & Microbe.
The researchers found that the beta-lactam antibiotics normally kill staph bacteria by inactivating the enzymes they use to strengthen and build cell walls. However, one of these enzymes called PBP2A is not turned off in MRSA when the infection is exposed to the antibiotics. In fact, the deadly superbug continues to build cell walls, and those walls are different than the ones built in normal staph infections. The Cedars-Sinai researchers said the altered cell walls have a powerful inflammatory response. That, in turn, made the mice treated with antibiotics even sicker.
What this Means for Patients
The scientists said their findings raise the possibility that prescribing beta-lactam antibiotics for humans with staph infections might be a bad idea. An additional problem is that physicians don’t always know what strain of staph a patient is infected with. It may take a day or two to determine if MRSA is indeed the culprit. That could leave doctors in a quandary over whether to prescribe these particular antibiotics.
Beta-lactam antibiotics are the most commonly used group of antibiotics. They are a first line of defense when the origin of an infection isn’t known, researchers said. The researchers did caution that their study only dealt with mice. They said more research with humans is needed before they could make any recommendations.
“Based on this research, clinical studies are warranted,” said study author Sabrina Mueller, Ph.D. “However, pending the outcome of those studies, physicians should follow current national guidelines set by the Infectious Diseases Society of America for antimicrobial treatment of staph infections.” Those guidelines list recommended treatments for each category of bacterial infection.