Necrotizing fasciitis caused by Serratia marcescens in two patients receiving corticosteroid therapy

Necrotizing fasciitis (NF), a devastating soft tissue infection, is rarely attributed to Serratia marcescens. We here report two patients with S. marcescens NF, both of whom had underlying renal disease and had been receiving corticosteroid therapy. The first patient, a 40-year-old man with systemic lupus erythematosus and uremia on prednisolone therapy, developed fulminant cellulitis and septic shock 1 month after a skin biopsy for cutaneous vasculitis of the left foot. The cellulitis evolved to NF, and blood and necrotic tissue cultures both grew S. marcescens. The patient completely recovered after debridement and ceftazidime therapy. The second patient, a 73-year-old man receiving prednisolone therapy for nephrotic syndrome, developed right leg cellulitis that evolved to NF. Blood and necrotic tissue cultures both grew S. marcescens. After aggressive debridement and ciprofloxacin therapy, the NF improved. However, the patient died of aspiration pneumonia and massive gastrointestinal bleeding 1 month later. These findings illustrate that S. marcescens should be considered as a potential pathogen causing NF in susceptible hosts.