In Vaccine News...

Perhaps news about vaccines and immunology stand out from the crowd more than they did before I read "The Panic Virus", or perhaps my fear of MRSA is palpable enough to create a cognitive bias toward any news in which that four letter acronym appears. In any case, the news I ran across today is heartening for those of us who know about MRSA, and timely considering my recent interview with Seth Mnookin.

What is MRSA?
Methicillin-resistant Staphylococcus aureus, or MRSA, is a drug-resistant bacteria that causes serious infections in humans. S. aureus is a very common bacteria, found on the skin and sometimes the nasal passages of healthy adults. Once it enters the body through a cut, puncture wound, or breathing tube the infection can either be minor and local (skin abrasion) or effect more serious internal structures such as bone or heart.

Penicillin was first used to treat S.aureus, but within fifteen years of widespread use the bacterium had outsmarted the treatment, with 80% resistance. Scientists discovered the mechanism of resistance, where the bacteria produces an enzyme (penicillinase) that renders the drug ineffective, i.e. the penicillin molecule can no longer bind to initiate cytolysis. Since then, the pharmaceutical industry has developed a line of penicillin antibiotics that are resistant to the enzyme produced by many strains of S. aureus, one of which is methicillin. As it happens, bacteria rapidly evolve and S.aureus has figured out resistance to methicillin...hence MRSA. This doesn't mean that we are stuck without treatment for resistant S.aureus infections, but the options are limited; particularly for children.

A Possible Vaccine.
Headlines from the University of Chicago Medical Center (UCMC) last July detailed the journey of one young doctor's quest to find a way to help children infected with pneumonia caused by MRSA in the lungs. Her perseverance and ingenuity coupled with the amazing resources provided by the research community at the University have resulted in the development of human antibodies to fight S. aureus lung infections. These antibodies protect the lung tissue from alpha toxin, a potent toxin released from S. aureus necessary to produce deadly infections. Injection of these antibodies could occur in children already infected with the bacteria in an attempt to assist the natural immune response and prevent the spread of infection.

The implications.
S. aureus causes infections that kill an estimated 80,000 people annually. MRSA infections are responsible for huge numbers of hospital stays by children and the incidence is growing exponentially, with a ten-fold increase between 1999 and 2008. Research such as that performed at large R1 institutions nationwide is critical in the effort to reduce health care costs and improve worldwide health outcomes.