Dermatology antibiotic mainstays ineffective for community-acquired MRSA infections

Dermatologists in outpatient practices should maintain an index of suspicion for infections caused by community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) and recognize the need to prescribe alternatives to the usual antibiotics that can be relied upon to effectively treat the majority of skin and skin structure infections they see, says Kenneth J. Tomecki, M.D., department of dermatology, The Cleveland Clinic Foundation.

"Ninety percent of skin and skin structure infections encountered by dermatologists in their offices or in outpatient clinics are caused by methicillin-susceptible S. aureus and beta-hemolytic streptococci, and those infections can be eradicated by treating empirically with a first-generation cephalosporin or an anti-staphylococcal penicillin. Those drugs, however, are not effective against CA-MRSA," Dr. Tomecki says.

Seventy-five percent of CA-MRSA infections involve the skin, and they typically occur in younger persons, especially in athletes who play contact sports, individuals who have been recently released from prison or in individuals who are drug abusers. Any of those findings in a patient who presents with a furuncle or cellulitis suggests that a specimen be obtained for culture and sensitivity testing.

Incision and drainage is of paramount importance in treating any furuncle/abscess, and may be curative by itself in about 75 percent of CA-MRSA infections. When an antibiotic is needed, trimethoprim/sulfamethoxazole (TMP/SMX) can be considered first-line except in geographic areas where resistance to TMP/SMX is high. Clindamycin and tetracycline represent good second-line choices in the latter situation. Other alternatives include the newer antibiotic linezolid (Zyvox), or vancomycin or daptomycin (Cubicin) if the infection is severe.

"Patients should also be advised about using antibacterial soaps or washes and other good hygiene measures, and dermatologists should also not forget about hygiene practices, including the frequent use of alcohol-based hand rubs," Dr. Tomecki says.