MRSA is the description of a strain of the bacteria named Staph Aureus that is characterized by resistance or non-responsiveness to the strong antibiotic methicillin. This is determined by placing the bacteria on a culture plate with a “dose” of methicillin and watching to see if the bacteria’s growth is halted. When the bacteria continue to grow in spite of a particular antibiotic it is labeled resistant to that antibiotic. If the bacteria stop growing it is sensitive or responsive to the antibiotic it was tested against. The bacteria for this type of test is usually obtained from a sample obtained from a nasal swab or skin wound culture. Occasionally it can be a culture taken from fluid obtained from the lungs in more serious conditions.
MRSA has evolved over the last several years from a strain of bacteria rarely seen to one that is common. It has now even been termed a community acquired (CA) strain of bacteria. In the past MRSA was typically described in severely immune compromised or hospitalized patients. This, however, is no longer the case. In fact, this type of bacteria has become the top suspect for rapidly changing “bumps” or abscesses that occur in infants, toddlers, and adolescents. It also is a frequent culprit in complicated pneumonias.
It is important to be aware of MRSA in order to correctly choose an antibiotic that will treat this type of infection. This is necessary in order that it does not continue to grow or become more invasive infecting the blood stream. However, it is also important not to over treat an infection in fear of MRSA. This would be a mistake which would likely create more strains of resistant bacteria. These type decisions are increasingly important as more “super bugs” emerge that do not respond to the antibiotics we currently have available. Currently, the majority of MRSA infections can be effectively treated with oral antibiotics such as bactrim or clindamycin as long as they are recognized in a timely manner. Therefore it is crucial to obtain a culture whenever possible to provide the best treatment options and identify MRSA.
Next month we will discuss how MRSA can be transmitted and what type of physical findings might make you suspicious of an MRSA infection.