A drug-resistant strain of “superbug” called MRSA (methicillin-resistant Staphylococcus aureus) has been in the news recently. MRSA is transmitted by skin-to-skin contact or by sharing infected items such as towels or sports equipment. It generally enters the skin through cuts and abrasions, causing boils and painful abscesses in the skin. However, if it enters the bloodstream it can attack internal organs and kill the patient.
MRSA was a rare hospital-based infection until the 1990s. Then it began to show up in prisons, locker rooms and gyms, and poor urban communities. It is now the most common cause of soft tissue and skin infections seen in hospital emergency rooms (“Methicillin-resistant S. aureus infections among patients in the emergency department”, N. Engl. J. Med. 355:666-674, 2006). It is often misdiagnosed and is very difficult to treat; more than half of all patients who come to emergency rooms with MRSA infections are treated with antibiotics that don’t kill it.
Last week, scientists at the Centers for Disease Control and Prevention reported that MRSA may be even more prevalent and more dangerous than previously thought. They estimate that MRSA may contribute to more deaths per year in this country than AIDS (“Invasive Methicillin-Resistant Staphylococcus aureus Infections in the United States”, JAMA 298:1763-1771, Oct. 17, 2007).
Also last week, the news media reported the death of Ashton Bonds, a 17-year-old high-school senior, due to a MRSA infection that had spread to his liver, kidneys, and lungs. As a result of his death, all 21 public schools in Bedford County, Virginia were shut down briefly for cleaning and disinfection.
Epidemiologists worry that the rise of MRSA is the natural outcome of the over-use of antibiotics, which only encourages bacteria to evolve toward antibiotic resistance (for more on the subject of antibiotic resistance, see p. 18 of Human Biology, 5th ed.) This bug will be hard to kill. Keep an eye on it.
