by Elise Wachspress
Staphylococcus aureus (commonly called Staph) is found on the skin and in the nose, throat, and gastrointestinal tract of about a third of the human population. Staph is one of the many “commensal” bacteria that routinely make their homes in our bodies, usually without incident.
But if Staph grows unchecked, it can cause problems. Staph infections on skin and other soft tissues account for about 14 million outpatient or emergency visits in the U.S. each year, and some populations, especially those in military training, experience significantly greater risks.
Staph can also become more invasive, infecting deep tissues, the lungs, blood stream, skeletal structures and joints, urinary tract, or heart lining. It can even cause sepsis, an especially dangerous systemic condition. Low-birth-weight babies, nursing homes residents, surgical patients, diabetics, cancer patients, or anyone with “foreign” appliances in their bodies (like implants, catheters, or ventilators) are more vulnerable to these kinds of Staph infections.
Generally, our bodies are quite adept at building weaponry—antibodies—against bacteria and viruses. Once the body produces these defenders, they tend to become part of a lifelong arsenal, effective deterrents against future infection by that specific interloper. But although healthy people from infant to adults carry Staph antibodies, these often fail to keep this particular bacteria from re-establishing itself. In fact, once you’ve had a Staph infection, you are more likely to get the infection again, even if you’ve been effectively treated with surgery or antibiotics.
The rise of antibiotic-resistant strains—namely methicillin-resistant Staph aureus, commonly known as MRSA—makes this problem especially worrisome. We are running out of antibacterial armaments to stop MRSA infections, and the cost of the fight is astronomical, estimated at over $10 billion per year in the U.S. alone. Finding a new way to reduce MRSA infections is critical.
University of Chicago microbiologists Olaf Schneewind, MD, PhD, and Dominique Missiakas, PhD, have found that a protein, SpA, which rides on the surface of the Staph bacterium blocks the development of effective antibodies. The Schneewind/Missiakas team cleverly generated mutant proteins, with new chemical groups at the binding sites of SpA, disordering the bacterium’s ability to block the development of antibodies. Early studies show these new proteins are effective in helping the immune system respond much more effectively to Staph colonization, and now the team is tweaking the molecules to find the most powerful version.
With the support of the Polsky Center for Entrepreneurship and Innovation, they have now launched a new company, ImmunArtes, to move their discovery toward commercialization. In December, the team won a $175,000 investment from the University of Chicago Innovation Fund.
In theory, the modified molecule could be a twofer: the basis for a vaccine against MRSA and a potential treatment for those already infected. The team recognizes the problem implicit in the latter strategy: MRSA can become lethal so quickly that the patient might die before the body can make enough antibodies.
The vaccine strategy also presents challenges. Several pharmaceutical companies (Merck, GlaxoSmithKline, and Novartis) have tried in vain to develop Staph vaccines or immune therapeutics; others (Pfizer and MedImmune), are still trying. What makes the prospect of a successful vaccine or antibody therapy so daunting is the multitude of evasive mechanisms deployed by Staph. Nevertheless, Schneewind and Missiakas are confident their vaccine strategy can overcome these obstacles, help decolonize Staph in humans, and reduce the risk of new Staph infection. The team is launching an aggressive development plan, producing clinical grade vaccine, generating preclinical data, and launching a human trial within the next three years.
The value of an effective vaccine would be tremendous. The nursing home industry is already taking note, and gyms, schools, and daycare centers will certainly be important beneficiaries of a MRSA vaccine.
Success will put the world one tool closer in the battle against antibiotic-resistant superbugs.
Elise Wachspress is a senior communications strategist for the University of Chicago Medicine & Biological Sciences Development office