Community Acquired MRSA

Dr. Terry Murphy

ED Medical Director

Samaritan Hospital

MRSA is medical shorthand for Methicillin Resistant Staph Aureas. Community Acquired MRSA implies that this Staph bacteria is common and can be “caught” at many places in our community. Staph bacteria are commonly carried on the skin or in the nostrils of healthy people. Some Staph bacteria, like CA-MRSA are resistant to antibiotics like methicillin, a type of penicillin. CA-MRSA is not all that new.  What is new is that infections caused by this germ are occurring much more frequently in the community, not in the hospital, and are showing up in doctor’s offices.  As of 2004, 12 million skin infections cultured from outpatient settings in the U. S. were found to be caused by Staph Aureas, and almost 60 percent of those were from CA-MRSA. These infections do not get better with the standard antibiotics used to treat skin infections and sometimes are recurrent or keep coming back. MRSA can be present on, or in, certain areas of the body such as the nostrils, without causing infection, a situation known as colonization.  Persons who are colonized with MRSA can be a source of the infection for themselves and others.

Healthy persons of all ages are at risk for CA-MRSA. The bacteria are transmitted by skin-to-skin contact with a colonized or infected person or from material they have contaminated (towels, clothing, tissues, etc…). Outbreaks can occur, but most infections do not occur in outbreaks.  Factors associated with the spread of MRSA include crowded living conditions, less than optimum hygiene and skin- to-skin contact. Organized athletics participants, gym users and active children are at risk because skin injuries such as scrapes and cuts can allow the germ to gain access to deeper skin layers. Family members of infected persons are also at some risk. 

CA-MRSA most commonly shows up as a skin infection, which at first may not look very threatening. The infection often occurs after an injury that at first may not seem all that bad; but does not heal as expected or gets worse.  A small, hard, red painful sore may resemble a spider bite or large pimple, boil or abscess with pus or drainage. The skin surrounding the infection is often red, tender & swollen. If untreated, a more serious infection, such as infections of bones and joints. CA-MRSA can also cause pneumonia that may develop after a case of the bronchial flu or influenza.

CA-MRSA infections should be considered as the cause of any skin infection until laboratory tests like a culture show otherwise.  A culture taken from any drainage from the wound can usually identify the germ and the most appropriate antibiotic to use to treat the infection.  If there is no drainage to culture, an antibiotic (often more than one antibiotic is needed) that is generally known to be effective against CA-MRSA, should be started.

Prevention includes:

- frequent thorough hand washing with soap and water or an alcohol-based disinfectant.

- avoid sharing personal hygiene items like wash clothes & towels, razors, or bars of soap

- properly dispose of tissues and any material possibly contaminated by an infection

- keep an infected area covered with a dry dressing

- if you or someone in your family is found to be colonized with CA-MRSA, then expect to have to apply a topical antibiotic inside your nose and use an antiseptic body-wash for a week or so. 

Treatment of CA-MRSA caused skin infections may require a procedure to drain any fluid buildup and, usually an oral antibiotic. Mild superficial skin infections, like impetigo, can be often be treated with a topical antibiotic such as mupirocin (Bactroban).  However, as mentioned earlier, more significant CA-MRSA infections are resistant to the usual antibiotics historically prescribed for skin infections. Common antibiotics used to treat CA-MRSA include trimethoprim-sulfa (Bactrim), doxycycline (Vibramycin), clindamycin (Cleocin) and, for more serious infections, vancomycin (Vancocin). Clindamycin is useful because it is also effective against strep bacteria, another cause of skin infections. Unfortunately, some CA-MRSA is developing clindamycin resistance.

Persons who are determined to be colonized with CA-MRSA, commonly need to have Bactroban ointment applied inside the nostrils for 5 to 7 days and whole-body antiseptic showers with an antiseptic like chlorhexidrine (Peridex, Periogard).

Anyone who thinks they may have a CA-MRSA infection should see a physician.

This article is intended to provide useful information, not medical advice. This information cannot, and is not meant to, replace consultation with your physician regarding your individual circumstances.