Lower-Extremity Infections Caused by Serratia marcescens .

Serratia marcescens is a ubiquitous, facultatively anaerobic, gram-negative bacillus that has been cited to cause infection in immunocompromised populations. In the literature, S marcescens infections of the lower extremity have presented as granulomatous ulceration, abscess, bullous cellulitis, and necrotizing fasciitis. Herein we present a series of three cases of lower-extremity infections in which S marcescens was the sole or a contributing pathogen. We discuss the commonalities of these three cases as well as with those previously cited. All three patients presented with some combination of a similar set of clinical characteristics, including bullae formation, liquefactive necrosis, and black necrotic eschar. All three patients were diabetic and had peripheral vascular disease.