Community-acquired MRSA incidence increasing

September 1, 2006

According to the Centers for Disease Control (CDC), methicillin-resistant staphylococcus aureus (MRSA) has been recognized as a health problem for more than 20 years.

Dermatology Times asked editorial adviser Norman Levine, M.D., professor of medicine (dermatology), University of Arizona College of Medicine, and Moise Levy, M.D., chief, dermatology service, Texas Children's Hospital, and professor of dermatology and pediatrics, Baylor College of Medicine, to discuss the impact of the increasing incidence of community MRSA on dermatologists.

Dr. Levy: MRSA stands for methicillin-resistant Staphylococcus aureus. Resistance is conferred by a particular gene called the mecA gene; that governs the production of penicillin-binding protein. That is what prevents beta-lactam antibiotics from affecting cell wall synthesis.

Now, the problem is, while methicillin resistance has certainly been around for many, many years, at least as a hospital-or healthcare-associated form, within the past several years the community-acquired emergence of methicillin resistance has presented large clinical issues for those of us seeing patients in ambulatory settings.

Q Dr. Levine:
What is the magnitude of the problem now?

Dr. Levy: In Houston, about 70 percent to 75 percent of all the community-acquired staff isolates are methicillin resistant.

So it's huge in our area, and it certainly varies throughout the country and throughout the world. But clearly, once it gains hold within a community it spreads very rapidly.

Q Dr. Levine:
Are there differences between the hospital-or healthcare-acquired MRSA and the community-acquired MRSA?

Dr. Levy: That's an important question. The healthcare-associated MRSA, which was identified back in the 1960s, epidemiologically is distinguished by virtue of having a history of prolonged or recurring antibiotic exposures, chronic illness, indwelling percutaneous devices and the like. The healthcare-associated has very broad antibiotic resistance. In community-acquired infection, we're really looking at a very narrow pattern of antibiotic resistance and certainly with none of the risk factors that I outlined in the other setting.

Q Dr. Levine:
Do you think that's going to change over time in terms of antibiotic resistance?

Dr. Levy: I think certainly antibiotic resistance is the major threat with which we're all dealing at this point. It has been really consistent since the early reports of this problem.

Q Dr. Levine:
Are there differences between children acquiring these infections and adults?

Dr. Levy: Generally speaking the answer is "no" in terms of the condition itself. This tends to be more of a problem seen in kids than in adults but it certainly does not respect patient ages.

Q Dr. Levine:
What is the clinical import? Is this just another skin infection that we can deal with or is there something special about this issue?