The Superbug

By Dr. Brian Irwin

Methicillin-Resistant Staphylococcus Aureus (MRSA) has been getting a lot of coverage in the media recently. This antibiotic-resistant bacterium has been implicated in a number of deaths in the last few months, and is becoming a major public health concern. However, its important to understand this strain of bacteria in order to know if you are at risk for MRSA infections, what they mean and how to react not if, but when, someone you know is infected with MRSA.MRSA is not a new strain of bacteria. It was reported as early as the 1970s. However, with the dramatic increase in the use of antibiotics over the last few decades this form of staph is on the rise. Because it can cause infections that may not respond to antibiotics, this rise is rightfully concerning.Perhaps more important than understanding MRSA infections is understanding MRSA colonization. At any given time, around 25 percent of the U.S. population has a colony of staph bacteria living in their nose. This colonization is very different from an infection; these bacteria reside here in harmony with the other good bacteria that live on our skin and in our airways. This colony may fade away and come back. Over their lifetimes, 70 to 90 percent of the people in this country will have been colonized with staph. While most of that staph is not resistant to antibiotics, an increasing number of people (1 percent, according to the Centers for Disease Control and Prevention) are colonized with bacteria that are resistant. Historically, MRSA was considered a very aggressive bacterium that only afflicted those with weak immune systems. This form of MRSA still exists; its what is now referred to as HA-MRSA (hospital-acquired MRSA), as it was born from health-care settings, nursing homes, etc. CA-MRSA is the strain thats been receiving most of the attention in the press recently. CA-(community-acquired) MRSA infects otherwise healthy people with good immune systems who have not been in a hospital setting. This strain tends to be less aggressive than HA-MRSA, but nonetheless can lead to serious conditions, like pneumonia or meningitis.So whats a person to do to protect against this Superbug? First, we all need to realize its not the only Superbug out there. Bacteria of all types have been developing resistance to antibiotics over the years. Its scary to treat a patient with their third urinary tract infection, and by the time theyve been treated twice successfully the third urine culture shows that the bacteria has become resistant to 90 percent of all antibiotics, simply by cycling through the community for a few years. That strain of bacteria was exposed to kids on amoxicillin for ear infections, adults on z-packs for bronchitis and elders on cephalexin for a skin infection. In a very short period of time it evolved to survive in the presence of all those antibiotics; it became resistant. If were going to beat the Superbug we need to stop generating drug-resistant organisms faster that we can develop new antibiotics. We need to use antibiotics sparingly and only when they are absolutely needed, not for the common cold.The best way to prevent transmission of MRSA is through vigilant hand-washing. Alcohol-based hand cleaners are very effective for MRSA. Avoid anti-bacteria soaps unless youre in a health-care setting, as these can actually promote the growth of drug-resistant bugs.Realize that you may be colonized someday and that this is almost inevitable. Because of this fact, decontamination of entire school systems is somewhat ridiculous. MRSA is in the community. Its everywhere, so unless we screen every person who enters that school and deny them entry if they test positive for MRSA colonization, a decontaminated school will be contaminated again in a matter of weeks after reopening.It is true, however, that it is possible to eradicate MRSA from a persons nares or skin. Its possible to wipe out the colonization. A complex regimen of ointments and oral antibiotics has been effective at achieving high decolonization success rates, although long-term data on how effective this policy is remains to be thoroughly studied. So why dont we screen and decolonize everyone? First, if we did that, our CA-MRSA would likely become resistant to all the drugs we use for decolonization in essence the same situation that got us here in the first place. Second, MRSA colonization isnt usually a problem unless that person is, or is in close contact with, a patient with a weak immune system. In some people even those with normal immune systems MRSA skin infections (usually presenting as boils) do occur. In these patients recurrent infections may call for decolonization; however, this is not needed in every person in the community. We made MRSA, now we have to live with it. Until there is a risk-free way to decolonize the world, which will not likely happen, we have to look at each case individually and determine if it warrants treatment, decolonization and, in some cases, isolation until an infection resolves. Lets all do our part to fight what is not a single Superbug, but is actually evolution of an organism. Check out www.cdc.gov for more information.Dr. Brian Irwin is a family physician at Tamworth Family Medicine and Ossipee Family Medicine, divisions of Huggins Hospital.