The patient is a 45-year-old Native-American woman with severe insulin dependent diabetes and a long history of peripheral vascular disease. She is status post right above the knee amputation and a left femoral popliteal bypass graft 3 months prior to this admission. She had problems with a draining wound from her left thigh which was initially thought to be due to a stitch abscess and she underwent excision and drainage. Her wound had essentially healed when she developed recurrent cellulitis and swelling of her leg. She presents now, appearing ill, in the Emergency room on 7-31-02.

1. What is your differential diagnosis?