TORONTO, Oct. 12 -- Necrotizing fasciitis may be caused by methicillin-resistant Staphylococcus aureus, especially in areas where community-acquired MRSA is prevalent, researchers reported here.
Five of 30 cases (17%) of necrotizing fasciitis seen the University of Colorado Health Sciences Center over a 25-month period were caused by MRSA, reported Lisa Young, M.D., at the Infectious Diseases Society of America meeting.
Necrotizing fasciitis remains rare, said Dr. Young, but community-acquired MRSA is on the rise.
Typically, she said, physicians assume the cause is Streptococcus A, and they treat the condition with a broad-spectrum antibiotic that is ineffective against MRSA.
"What we would recommend, if a patient comes in with what looks like necrotizing fasciitis and you live in a an area of high prevalence of community-acquired MRSA, that you would initiate antibiotic therapy for MRSA as part of the empiric treatment while waiting for cultures," Dr. Young said.
Waiting for the typical treatment to fail before initiating therapy for MRSA would put patients at risk for severe tissue damage and even amputation, she said.
The recommendation makes sense, commented Michael Rybak, PharmD, of the anti-infective research laboratory at the Eugene Applebaum College of Pharmacy and Health Sciences in Detroit. "We now have an organism that is highly aggressive, highly virulent and in many patients can get into the deep layers of the skin," he said.
Using an agent active against MRSA "has to be in the back of your mind," he said. Luckily, he said, a range of agents is available, ranging from the newer drugs such as Cubicin (daptomycin) and Tygacil (tygecycline), as well as old standbys such as vancomycin and Cleocin (clindamycin).
In early 2005, researchers in Los Angeles reported that they had found 14 cases of necrotizing fasciitis among 843 patients whose wound cultures were positive for MRSA. In the wake of that report, Dr. Young said, she and colleagues at Colorado reviewed the 30 cases of the condition they had seen from January 2004 through February 2006.
In Denver, Dr. Young said, more than half of community S. aureus isolates are MRSA, so that prevalence is high.
Of the five cases of necrotizing fasciitis attributed to MSRA, she reported, all involved the extremities. Three of the five patients reported a "spider-bite lesion" two or three days before they were admitted. All were given empiric antibiotics to which their MRSA isolates were susceptible within 12 hours of admission, she said.
Patients required a median of six surgical procedures, number ranging from two to seven, she said. However, all five survived the condition and none needed an amputation.