Study Design: We will study 50 postoperative and traumatic wound infections and 50 closed soft tissue abscesses in intravenous drug abusers annually, from a general surgical service at Olive View County Hospital, affiliated with UCLA and the VA Medical Center West Los Angeles, in collaboration with Dr. Robert Bennion. Whenever possible, we will obtain tissue biopsies from the active edge of the wound for processing, along with pus from the wound.