Stories about killer bacteria ravaging your child's school gym, locker rooms and nursing homes have made for grabby headlines in recent years. But the truth is that such life-threatening infections with MRSA, or methicillin-resistant Staphylococcus aureus, are still largely confined to certain hospital settings, rather than the community at large. And even in the highest-risk health-care environments, according to a new report, the threat of MRSA infection is diminishing.
According to national data from 1997 to 2007, the overall rate of MRSA infections among some of the most vulnerable patients in a hospital those in the intensive-care unit (ICU) dropped by nearly 50%. That downward trend was true of all bloodstream infections among ICU patients, including infections with strains of staph that can be controlled with antibiotics, reports Dr. Deron Burton, a lieutenant commander in the U.S. Public Health Service at the Centers for Disease Control and Prevention (CDC), in a study in the Feb. 18 issue of the Journal of the American Medical Association. (See the most common hospital mishaps.)
Despite the reduction in infections generally, the proportion of all hospital-based bacterial infections caused by MRSA increased, by 26% over the same time period. Approximately 64% of ICU staph infections can now be traced to MRSA, according to an earlier survey conducted by the CDC. That means that the risk of bacterial infection for an ICU patient who has been given a catheter or central line is smaller than it was a decade ago, but if he or she does get an infection, it's more likely to involve an antibiotic-resistant strain of MRSA. "Our message is that the percentage of MRSA [infections] is still an important measure of the burden of antibiotic resistance in the health-care setting," says Burton.
The rise of antibiotic-resistant strains of bacteria like MRSA can be attributed largely to our increasing use and misuse of antibacterial drugs. Many patients mistakenly believe these drugs can quell colds and flu, illnesses that are caused by viruses, not bacteria, and are therefore unresponsive to antibiotics. Further, doctors commonly prescribe antibiotics improperly, while many patients who do need them fail to complete their full prescribed course. The former condition pushes bacteria to mutate and develop resistance, while the latter creates ideal conditions for resistant strains to flourish. One way to reduce drug resistance, then, is to reduce the reckless use of drugs.
The current study does not detail why bacterial infections are occurring less frequently than before, but Burton speculates that it may be a result of greater vigilance on the part of both hospitals and state health departments in detecting and controlling the spread of MRSA. During the 10-year study period, improved methods of inserting catheters, shorter leave-in times for catheters, as well as improved hygiene and isolation practices have all become more routine. The goal now is to further reduce the risk of MRSA in vulnerable populations by identifying them early on: according to the Association for Professionals in Infection Control and Epidemiology, 10 states currently require screening of high-risk patients, including those in the ICU and with weaker immune systems, for MRSA, and other states may soon adopt similar screening laws.