Nor do clinical features reliably distinguish CA-MRSA from MSSA infections. Cutaneous abscesses, often with necrosis an_d surrounding cellulitis, appear most often with CA-MRSA infections. A clinical review of available data on these infections² demonstrates that the absence of ran_domized, controlled trials keeps us ignorant about virtually every important aspect of their management. Only one nearly unanimous verdict emerges from the review: Incision an_d drainage are critical in the therapy of purulent lesions. The role, if any, of antimicrobial agents in decreasing the duration of infection, complication rates, or recurrence rates is unknown. Although CA-MRSA is usually susceptible to trimethoprim-sulfamethoxazole, tetracyclines, an_d clindamycin, most of the studies failed to demonstrate a convincing benefit from systemic antimicrobial therapy. The recommendation, repeated in this review, to use such therapy in patients with abscesses &gt5 cm in diameter comes from a single study in children an_d was not confirmed in another retrospective report. If systemic antimicrobial therapy proves beneficial, an important issue involves the use of clindamycin: Some strains susceptible to this antibiotic but not to erythromycin can potentially develop clindamycin resistance during therapy. How frequently this occurs — an_d whether there are any attendant therapeutic implications — remains uncertain.

Comment: The origin of these infections is also unclear: We don’t know how often they arise from organisms colonizing the nose, skin, an_d other sites in a patient’s body, as&nbspcompared with recent acquisition from other people, from objects in the environment (fomites), from pets. Nor do we know whether topical antimicrobials or antiseptics applied to the nares or the skin are useful in reducing recurrences or the spread to close contacts. Such profound uncertainties in managing an increasingly common an_d serious infection man_date prompt but careful prospective studies