Doctor On Call
Staph Scare

by Jeffrey Rehm, M.D.

One topic that seems to be cropping up more frequently is methacillin-resistant staphylococcus aureus (MRSA) . Schools have recently been vigilantly watching for open wounds and skin lesions on students and very carefully using disinfectant on all surfaces. What is MRSA? Where did it come from? Why is it in our schools?

Staph Aurei are bacteria that have lived on our skin for since humans have been on this earth. It can cause serious infections among other places in the lung and in the skin. Prior to antibiotics, staph infections carried a high mortality. Penicillin was introduced in the early 1940 and was able to effectively treat staph skin, lung and blood infections. Penicillin resistence was first noted in 1942 and by 1960, most staph strains were resistant to penicillin (therefore, penicillin was not longer an effective antibiotic for treatment of staph aureus). The mechanism of staph resistence was through a protein or enzyme elicited by the staph bacteria. The enzyme would break down the penicillin before reaching the penicillin-binding protein used to disrupt bacterial cell replication.

In 1959, a semi-synthetic penicillin, methacillin, was introduced which was resistant to the staph-producing enzyme. However, within a few years, staph developed resistance to methacillin, thus methacillin resistant staphylococcus aureus (MRSA) was born.

MRSA has been with us for a while, but mostly confined to the hospital, nursing or group homes and dialysis units. At Mary Washington Hospital, our staph is about 50% MRSA. So what is the big deal? In the early 1980's, MRSA began to be seen in the community, mostly with IV drug users. However, in the 1990's, MRSA began to show up in people without prior known risk factors or exposures. This was termed community acquired MRSA or CA-MRSA. It appears that genetically, hospital acquired MRSA (HA-MRSA) is different than CA-MRSA.

CA-MRSA usually is seen as a skin infection in children and adults (ie., Furuncles, abscesses and boils- basically "pus" pockets). Factors believed to be associated with CA-MRSA are crowded living conditions, frequent skin-to-skin contacts, compromised skin, sharing contaminated personal items such as towels and razors and lack of cleanliness. Thus in the schools there is a push to try to decontaminate surfaces, which may or may not help.

The treatment for CA-MRSA is different than HA-MRSA. Although CA-MRSA is resistant to methacillin as the name implies, it is susceptible to trimethoprim-sulfamathoxazole (Bactrim- used for bladder infections) and tetracycline. Resistence to clindamycin, quinolones and cephalosporins varies as to regions. Treatment should include draining on any pus pocket, followed by a culture of the pus, followed by antibiotics. Sharing of towels, razors or other personal items should be discouraged.

Although antibiotic resistence can be frightening, it will always be with us. Attending to personal hygiene is probably the best way to avoid CA-MRSA infections. After reading this, my children say they can't share "personal" Halloween candy, for fear of MRSA. I guess I can't win.

Dr. Jeffrey Rehm is the father of three in Fredericksburg, and a pulmonologist at both Mary Washington Hospital and 521 Park Hill Drive, (540)899-1615.