Leg ulcers and abscesses caused by Serratia marcescens

Cutaneous infections caused by S. marcescens, a gram-negative bacillus belonging to the family of Enterobacteriaceae, are uncommon but may be predisposed by immunocompromised conditions or pre-damaged skin. A 73-year-old man presented with multiple ulcers and painful nodules on the lower right leg as well as abscesses on the right malleolus lateralis. He had been treated with oral penicillin without success. Due to chronic obstructive pulmonary disease, he was receiving a systemic therapy with corticosteroids. In addition, he had a post-thrombotic syndrome of the lower right leg. Serratia marcescens was the only microorganism isolated from all cultures performed. After a microbial sensitivity test, ertapenem 1 g/day was given intravenously for 10 days, followed by oral administration of ciprofloxacin 500 mg 1-0-1 for a further 7 days. This therapy resulted in the resolution of all lesions. This rare skin infection with S. marcescens needs specific microbiological diagnosis and adapted antibiosis.