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Localized erythema with induration and purulent drainage
Abscess formation
Folliculitis commonly observed
Gram stain of pus shows gram-positive cocci in clusters; cultures usually positive
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May begin around one or more hair follicles, causing folliculitis
May become localized to form boils (or furuncles)
May spread to adjacent skin and deeper subcutaneous tissue (ie, a carbuncle)
Deep abscesses involving muscle or fascia may occur, often in association with a deep wound or other inoculation or injection
Necrotizing fasciitis has been reported with community strains of methicillin-resistant S aureus (MRSA)
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Cultures of the wound or abscess material almost always yields the organism
In patients with systemic signs of infection, blood cultures should be obtained because of potential bacteremia, endocarditis, osteomyelitis, or metastatic seeding of other sites
Patients who are bacteremic should have blood cultures repeated every 24–48 hours during therapy to exclude persistent bacteremia, an indicator of severe or complicated infection
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Proper drainage of abscess fluid or other focal infections is the mainstay of therapy
Incision and drainage alone is highly effective for the treatment of most uncomplicated cutaneous abscesses
A small benefit can be obtained from the addition of antimicrobials following incision and drainage (Table 33–1)
In areas where methicillin-resistance among community S aureus isolates is high, recommended oral antimicrobial agents include clindamycin, trimethoprim-sulfamethoxazole, doxycycline, or minocycline
When the risk of methicillin resistance is low or methicillin susceptibility has been confirmed by testing of the isolate, consider dicloxacillin or cephalexin
Treatment for 5–7 days is sufficient in most cases
For complicated infections with extensive cutaneous or deep tissue involvement or fever, initial parenteral therapy is often indicated
When methicillin resistance rates are high (> 10%), empiric therapy with vancomycin is a drug of choice
For infections caused by methicillin-susceptible isolates
Cefazolin, 1 g intravenously or intramuscularly or
A penicillinase-resistant penicillin such as nafcillin or oxacillin in a dosage of 1.5 g intravenously every 6 hours
For treatment of skin and skin-structure infections
Linezolid, 600 mg orally or intravenously twice a day for 10–14 days
Other alternatives see Table 33–1
Duration of therapy
Total duration of therapy for soft tissues infections will depend on clinical response and effectiveness of drainage/debridement
Courses of 7 days with early transition to oral therapy are effective in many cases