VAIL, COLO. – Current broadly endorsed guidelines for outpatient management of skin and soft tissue infections in an era of rampant community-acquired methicillin-resistant Staphylococcus aureus emphasize incision and drainage without routine antibiotic coverage.
"In general, for a boil or abscess or pimple that a parent is complaining about, if you drain it, that’s good enough. Patients don’t need antibiotics unless they’re presenting with more severe systemic signs of infection," Dr. James K. Todd explained at a conference on pediatric infectious diseases, which was sponsored by Children’s Hospital Colorado in Aurora.
Dr. James K. Todd
The guidelines were jointly developed by the American Medical Association, the Centers for Disease Control and Prevention, and the Infectious Disease Society of America in 2007. The underlying strategy is to avoid unnecessary prescribing of antibiotics, with all of its attendant problems.
The effectiveness of this guideline-recommended, drainage-only approach was underscored in a recent randomized, controlled trial that was published after the guidelines release. The study involved 200 pediatric patients with uncomplicated skin infections, 69% of whom had methicillin-resistant S. aureus (MRSA) cultured from their wounds. All participants underwent drainage of their focal infection and were randomized to 7 days of clindamycin or cephalexin. Clindamycin (Cleocin) is effective against MRSA; cephalexin (Keflex) is not.
Complete resolution of the skin infection was observed by day 7 in 94% of those who received clindamycin and similarly in 97% of patients in the cephalexin arm (Pediatrics 2011;127:e573-80).
"This study shows that there’s no need for antibiotics because Keflex is not effective for MRSA," commented Dr. Todd, professor of pediatrics, microbiology, and epidemiology at the University of Colorado at Denver.
The abscess is the sine qua non or "essential element" of S. aureus infections. The organism has an affinity for injured tissue, and it likes to localize. These focal infections must be drained in order to expose S. aureus harbors.
"As Johnnie Cochran might have said, ‘Antibiotics contain, but you still have to drain.’ Keep that in mind," Dr. Todd added.
The guidelines recommend incision and drainage of purulent skin infections, with the aspirated pus sent off for culture and susceptibility testing. Supplemental antimicrobial treatment with coverage for MRSA is to be considered only in patients who have systemic or quite severe local symptoms, who are immunosuppressed, or whose infection isn’t responsive to drainage.
On the other hand, the guidelines note, in cases of possible cellulitis without abscess, then group A streptococcus infection becomes a consideration and antimicrobial coverage for that pathogen is appropriate. Clindamycin is a good choice because it is effective against both group A streptococcus and MRSA, Dr. Todd continued.
In confabbing with other pediatric infectious disease specialists, he said the shared anecdotal experience has been that the kids who develop severe MRSA infections almost never previously came in for the occasional skin infection with MRSA.
"What this implies is that when you get exposed to MRSA, even though we know that there are some more virulent strains, there are also different host responses, so if you get buttock lesions initially that’s probably all you’re going to get. You’re not going to go on to develop a necrotizing pneumonia or septic thrombophlebitis," according to Dr. Todd. "I think there’s some relief in the idea you can be patient with kids with recurrent boils, even though the mother is going crazy about it. You can recommend simple measures, and in time the problem is going to go away, and it’s not likely to be going to cause serious complications."
He’s not a fan of MRSA carriage eradication regimens. Like cockroaches, MRSA is very difficult to get rid of. Most attempts at eradication fail, with recolonization occurring by about 6 months. A Cochrane review found no evidence that any antimicrobial regimen for eradication is better than placebo (Cochrane Database Syst. Rev. 2003 [doi:10.1002/14651858.CD003340]).
Nevertheless, he’ll consider an attempt at eradication in patients who’ve had three or more episodes of skin or soft-tissue infection, those who have multiple family members with recurrent MRSA disease, and patients who have not responded to hygienic measures and bleach baths.
"Most methods really don’t work in the long term, but we might recommend considering an attempt at eradication in those situations, while recognizing that we’re really just buying time until the MRSA goes away on its own," Dr. Todd said.
Dr. Todd said that he had no relevant financial disclosures.