S1833 A Rare Case of MRSA Enterocolitis Treated With Oral Vancomycin

Introduction: Nosocomial diarrhea affects up to one third of hospitalized patients. In the 1950’s MRSA was thought to be the primary pathogen in pseudomembranous enterocolitis associated with antibiotic use or recent abdominal surgery. By the late 1970’s Clostridium difficile was identified as another pathogen causing pseudomembranous colitis. Managing diarrhea in hospitalized patients requires multiple investigations in order to treat appropriately without causing further nosocomial infection. Since the eclipse of C. diff clinicians have stopped investigating for other less common pathogens. Consequently, the diagnosis of MRSA enterocolitis has become only a historical cause. It is imperative to consider historical, but more sinister pathogens not routinely covered in laboratory testing as MRSA enterocolitis infections have been known to progress to severe systemic infections and thus the delay or misdiagnosis can result in inappropriate treatment, prolonged hospitalizations, sepsis and/or death. Herein we present a case of MRSA enterocolitis in the absence of recent abdominal surgery or antibiotic use and was successfully treated with oral Vancomycin. Case Description/Methods: A 71 yo F with extensive PMH, presented with acute watery diarrhea, fecal incontinence and abdominal cramping. She was hospitalized a few months prior for surgical mesh repair for abdominal hernia and had not been on any antibiotics. On arrival the patient was hemodynamically stable and afebrile. Labs were remarkable for AKI. Initial CT of the abdomen and pelvis revealed large anterior abdominal wall hernia without signs of obstruction or colitis. Stool C.diff toxin and PCR were negative. Stool cultures grew MRSA. The diarrhea significantly improved with oral vancomycin 125 mg and IV hydration. The patient was discharged on hospital day 12, with two more days of antibiotics to complete a 14-day course. On follow up, the patient’s diarrhea had completely resolved. Discussion: In the absence of C. diff toxin or PCR positivity, one should investigate for other pathogens of nosocomial diarrhea. MRSA colitis is a distinct clinical entity from C.diff, including the pathogenesis, gross and microscopic pathology, investigations, and management. Although the fatality rates have declined since 1950, MRSA colitis is still more sinister and one should proceed with caution and treat accordingly if diagnosed. Early diagnosis of this disease requires high clinical suspicion and early treatment to prevent its progress to severe systemic infections.