Peritonitis, as a Result of a Retrograde Postoperative Incisional Infection

An 8-year-old Quarter Horse × walking horse cross mare was referred for treatment of septic pedal osteitis and subsequently developed a cecal impaction which was resolved surgically. Postoperative enteritis and incisional drainage developed in the short-term postoperative period. One month postoperatively, the mare developed an acute septic peritonitis with Streptococcus equi zooepidemicus that was likely a sequela to the incisional infection. Systemic antibiotic therapy and peritoneal lavage were instituted; however, repeated culture and sensitivity of the abdominal fluid revealed a multidrug resistant Escherichia coli. In the face of antibiotic treatment failure, medical grade Phaenicia sericata larvae were placed into the abdomen to be used as a biological debriding agent. Clinical improvement was seen for 6 weeks, until the mare was euthanized due to a small intestinal strangulating lesion. Additionally, this case report is a description of the novel use of medical maggots in the treatment of a multidrug resistant peritonitis in a horse.