MRSA Enteritis

Abstract

Purpose: Case:An 83 year old retired dentist presented to the Emergency Room from a nursing facility with a 3 day history of left lower quadrant abdominal crampy non-radiating pain, anorexia and diarrhea. He was hospitalized for a hip fracture complicated by a pneumonia three weeks prior to the presentation. His past medical history was significant for Diabetes Mellitus, Atrial fibrillation, Hypertension and Gout. The patient was on Lipitor, Propranolol, Insulin, Warfarin and Colchicine. On exam, patient was an ill appearing elderly male who was afebrile but tachycardic with an irregular rhythm. The abdominal exam revealed moderate tenderness to palpation in the left lower quadrant without signs of peritonitis. On laboratory data was a leucocytosis of 22,000/ul, a creatinine of 1.3 mg/ml, an INR of 5.7 and urinalysis revealed 8-10 Leucocytes. A CT scan of the abdomen with intravenous contrast was obtained to rule out diverticulitis, which showed a long segment of circumferential mural thickening involving the distal duodenum and proximal jejunum with adjacent stranding. The patient was started on intravenous Metronidazole and Levofloxacin without any improvement by day 4. It was decided to perform an enteroscopy and a colonoscopy as soon as the INR level was acceptable. On day 5, stool cultures grew large numbers of Methicillin Resistant Staphylococcus aureus (MRSA). The patient was started on Vancomycin with complete resolution of pain and diarrhea by day 7 of hospitalization. Discussion: Humans are a natural reservoir of SA. 30-50% of healthy adults are colonized intermittently with the organism. The respiratory tract is the major harbor being involved in up to 15-44% of cases. 5.3% of the patients who are admitted for surgeries and 9% of health care workers have been found to carry MRSA. MRSA enteritis is a very unusual cause of diarrhea which has not been widely studied. Patients present with fever, profuse watery diarrhea and evidence of systemic inflammatory response which may progress to multi-organ failure. The diarrhea typically presents 2-3 days post-operatively and lasts for 5 or more days. Recent surgical operation, antibiotic and/or gastric acid suppressing drugs are usually associated with its occurrence. Post-operative MRSA enteritis can be fatal unless treated with antimicrobial therapy. A Japanese multicentric study assessed the efficacy and safety of Vancomycin in the treatment of MRSA enteritis. 49 patients with diagnosed or strongly suspected MRSA enteritis were given Vancomycin 500 mg four times a day with a 100% clinical response rate. Lately there has been a considerable interest in the specific phenotypic and genotypic characteristic of the organisms causing MRSA enteritis.