Gettysburg Medical News
 The Clinical View
 by P.E. Hoffsten, M.D.
 20 July 2005

WHAT IS MRSA?

            Of the many types of infections that may occur, staphylococcal infections are one of the most notorious.  There are two major types of staphylococcal bacteria.  One of these is called staphylococcal aureus and is the most common cause of very severe infections.  The other is called staph epidermatous.  This later bacteria is on the surface of almost everybody’s skin.  While it can cause serious infections especially of the skin, the more dangerous bacteria is called staphylococcus aureus.

            In 1938, Penicillin was discovered by Sir Alexander Flemming in England.  At that time, nearly all bacteria were sensitive to Penicillin, including the staph aureus.  Over the years of use of Penicillin, this particular organism became more and more resistant to Penicillin. Today most staphylococcus aureus colonies that are isolated in our laboratories are resistant to Penicillin.  When this trend began in the 1960’s and 1970’s, pharmaceutical companies began to develop new kinds of Penicillin other than the naturally occurring one produced by the fungus that Sir Alexander Flemming worked with.  Dr. Flemming discovered “Penicillin G”.  This type of Penicillin has to be injected as stomach acid will destroy the Penicillin G if taken orally.  Penicillin V came along in the 1960’s and was the first form of Penicillin that could be taken as an oral pill. That was followed by other oral Penicillin’s, including Amoxicillin, Ampicillin and eventually Oxacillin.  Oxacillin and Methicillin were developed specifically because the staphylococcus was becoming increasing resistant to both injectable Penicillin and oral Penicillin alternatives.  Initially, virtually all staphylococci were sensitive to Methicillin which was a specific injectable type of Penicillin.  Today, we rarely use this drug because we have more effective alternatives.

            In the 1980’s, staphylococcus aureus developed resistance even to Methicillin which was originally designed to kill it.  Fortunately by this time, we had other antibiotics that would work but then a strange dilemma began to become apparent.  That was, that as staphylococcus aureus became resistant to Methicillin, it became resistant to multiple other antibiotics in addition.  The name of this type of organism was called methicillin resistant staphylococcus or MRSA.

            Fortunately, there is still at least one antibiotic that will kill staphylococci.  This antibiotic is called Vancomycin but it must be administered intravenously. This means that a person cannot simply take a bottle of pills home and effectively treat MRSA.  It usually has to be treated in a hospital setting or with daily visits to an outpatient clinic to receive intravenous infusions.

            Television, magazines, and newspapers tend to spectacularize the dangers of MRSA.  People magazine recently described a child that had an MRSA infection and died of it.  While this certainly can happen, in fact, the MRSA is really no more virulent or tissue damaging than staphylococci that are sensitive to Methicillin.  The problem is that some infections  are perceived to be relatively minor and are treated with antibiotics to which the MRSA are insensitive. If the antibiotic given is ineffective, the infection has a 3-4 day head start and worsens before it is recognized that the antibiotic given isn’t working.  By that time, very serious damage can occur from the infection.

      Staphylococcal infections with MRSA have presented multiple times in the clinic in the past year.  Examples include  a wrestler who had developed an abrasion on his elbow.  He was seen in his local clinic with the abrasion very inflamed and appearing to represent an impetigo-like sore.  He was started on an antibiotic called Keflex, which the methicillin resistant staphylococcus in this wound was resistant to. Three days later, he returned and the wound was no better.  At that point, cultures were taken of the wound and it demonstrated the MRSA.  It is noteworthy that while the arm had gotten no better in this time, it had not gotten particularly worse, and to describe the MRSA as a flesh-eating monster is really inaccurate.  He was started on local applications of an antibiotic called Silvadene and in several days time the wound on his arm had completely healed.

            Another example of an MRSA infection that was much more serious involved a lady who had an artificial heart valve.  She developed a pneumonia and was being treated in the hospital with antibiotics intravenously.  After four days in the hospital, her pneumonia was getting better but she had a temperature develop again. On this occasion, blood cultures were done demonstrating MRSA growing in her blood.  Whenever this happens in a person with an artificial heart valve, it must be assumed that the artificial heart valve itself is infected.  This lady required six weeks of continuous intravenous antibiotic treatment to completely clear the infection.  This was achieved although her ordeal of six weeks of antibiotic therapy was difficult for her.

            Lastly, there are some individuals who have severe chronic infections such as chronic lung disease, chronic urinary tract infections and severe skin infections, and those who have spinal cord injuries and paraplegia or quadriplegia. These later individuals cannot feel the pressure points in their body and tend to develop bed sores.  When these bed sores become infected with MRSA, they are extremely difficult to heal taking months of treatment.

            In summary, MRSA is something to be highly respected and is respected in the practice of medicine to day.  However, these organisms are not horribly virulent, flesh-eating bacteria, so much as they are dangerous because very frequently we give inadequate antibiotic treatment not suspecting that they are present.  The healthcare providers at your local clinics are aware of these problems and can help in arranging for appropriate treatment of various infections.