When Mr. Wilson (name changed to protect confidentiality) arrived at the emergency department at the James A. Haley Veterans Hospital in Tampa, Fla., one night in October, he had a common complaint.
"I think I've gotten bitten by a spider," he said. On his thigh, several large raised skin lesions were visible.
"These aren't spider bites," his physician, Dr. Yvonne Dunn, remarked. "You have a skin infection called community-acquired MRSA. Your boils will need to be opened and drained, but with proper care, you should be OK."
The patient listened intently. "Just my luck," he said.
Staphylococcus aureus is one of the most common germs we encounter each day. It is a normal (and usually harmless) germ on our skin and in our nose.
Infections may occur when the organisms get into the body through breaks in the skin (such as cuts, scrapes, open wounds, surgical incisions or catheters in a person's vein) and multiply rapidly. MRSA stands for methicillin-resistant Staphylococcus aureus. MRSA is a more resistant form of the germ that has become a serious cause of human infections in the hospital, and recently, in the community.
MRSA has been a serious problem in hospitals since the early 1960s, when increasing use of powerful antibiotics led to germ resistance.
In health care settings, MRSA causes tens of thousands of surgical infections, bloodstream infections, pneumonias and infections of medical devices each year. Concern over the spread of MRSA between patients in the hospital is so great, that many hospitals isolate patients who have MRSA so that other patients are not exposed.
Over the past decade, there has been a substantial increase in the number of MRSA infections in people who have never been hospitalized. Experts believe these are due to a new strain of MRSA that originated outside of the hospital. This germ, called "USA 300," is spreading across the country and producing hundreds of thousands of new infections each year. These infections can range from simple skin boils or abscesses to pneumonia and even to life-threatening infections.
Because USA 300 has become so widespread, the strain is now commonly found in hospitals, where MRSA made its first appearance decades ago.
"We've really come full circle with MRSA," Dunn said. "Now the community strain of staph is the predominant strain in the hospital, and it's far more aggressive in many ways."
Outside the hospital, most MRSA infections cause simple skin infections.
"If it is on your skin and has lumps, bumps or pus, then there's a good chance it's due to Staphylococcus aureus," said Dr. John Toney, an infectious diseases specialist at the Tampa VA Hospital.
In many cases, these lesions are initially misdiagnosed as brown recluse spider bites or other insect bites.
"Brown recluse spiders tend to be indigenous to the central and Southwestern U.S.," Toney said. "They are much rarer in places such as Florida and the Atlantic and Pacific coastal states. In fact, many of these 'spider bites' are being misdiagnosed and are really MRSA skin infections."
Though there is a tendency for physicians to prescribe antibiotics for infections, an antibiotic pill may not be the answer for MRSA.
"With the community strains," Toney asserted, "the most common class of antibiotics, which include penicillin, are usually not effective. Although we have other antibiotics we can prescribe, the best therapy is to drain the pus."