• A posttraumatic exogenous endophthalmitis developed that was due to Peptostreptococcus. This Gram-positive anaerobe was isolated in pure culture from vitreous. The endophthalmitis showed a bacteriologic and clinical relapse despite conventional routes of antimicrobial treatment. A second clinical relapse occurred despite apparent vitreal sterilization with intravitreal antibiotics. The response to vitrectomy was impressive, and postoperatively the patient's visual acuity improved to 20/20.