Methicillin-resistant Staphylococcus aureus, or MRSA, is often called a “superbug” by the media, bringing to mind an extremely infectious and deadly disease, like a modern black plague. The reality of MRSA is not that simple, however. MRSA is indeed infectious, difficult to treat sometimes and can cause death, but we still have tools in our arsenal to fight the drug-resistant bacterium.
MRSA: The Background
Methicillin-resistant Staph aureus is not a new disease. Staphylococcus aureus is a gram-positive bacterium that is present on the skin of many healthy people. S. aureus does not usually cause problems, but if the bacterium infects a cut or wound, or if someone is seriously ill with another disease or has an impaired immune system, it is possible for S. aureus to cause an infection. Such an infection can remain localized to the skin, and it usually does, but there is the potential of an untreated infection to spread to other parts of the body. This is a life-threatening situation and it can cause death if not treated because the vital organs can be affected. Staph aureus is easily wiped out with simple antibiotics, such as penicillin– except when it’s MRSA.
MRSA is often used as the name of the disease caused by methicillin-reistant Staphylococcus aureus, as well as the name of the organism itself. MRSA is the same as regular Staph aureus, except it has a chemical defense mechanism against certain types of antibiotics and is therefore resistant to them. MRSA produces an enzyme that cuts part of the chemical structure of certain antibiotics apart and renders them ineffective. MRSA is resistant to multiple antibiotics of the beta lactam class for that reason, including amoxicillin, penicillin and cephalosporin. MRSA is of course resistant to methicillin, but methicillin is not used clinically anymore; it is mostly useful for determining drug resistance of cultures in the laboratory.
MRSA usually causes a skin infection, so symptoms may include a wound that doesn’t heal, redness, rash and inflammation of the skin. More severe potential symptoms of MRSA include fever, a general feeling of illness, fatigue and other nonspecific symptoms of infection. If MRSA gets into the body and affects vital organs, complications such as pneumonia, endocarditis, a drastic drop in blood pressure, cardiac arrest and death can occur.
MRSA remains susceptible to certain antibiotics, but these antibiotics may have more severe side effects than antibiotics such as penicillin. Antibiotics may be given orally or intravenously. If MRSA invades the bloodstream, intravenous antibiotics are required to fight off the infection.
Some strains of MRSA are becoming resistant to other types of antibiotics, as well. For instance, some MRSA strains are resistant to vancomycin, which belongs to an entirely different class of antibiotics. The real danger of MRSA lies not in its virulence, but in its increasing difficulty to treat.