MRSA in the Blood From MRSA in the Gut: A Rare Presentation of MRSA Bacteremia From a Gastrointestinal Source

Abstract

MRSA causes a wide variety of diseases in humans ranging from benign skin infections to life-threatening sepsis. Blood stream infections (BSI) secondary to MRSA have high mortality rates of 20-40%. Immunocompromised patients are at risk of acquiring health care associated MRSA BSI. Most common sources for MRSA BSI are intravascular inoculation, urinary tract infection and pneumonia. We report a case of MRSA BSI originated from gastrointestinal tract. A 23-year-old African-American male with a history of HIV presented with odynophagia, weight loss and hematochezia. Subsequently, he developed septic shock due to MRSA bacteremia. The initial physical examination was significant for cachexia, oral thrush, grade III systolic murmur in mitral area, perianal ulcers, painful digital rectal exam with few stains of blood on the gloved finger. Laboratory data was significant for CD4 count of 21 cell/mm3, hemoglobin of 9.9 g/dl, creatinine of 1.53 mg/dl. Bactrim and Azithromycin was started for HIV prophylaxis. Upper GI Endoscopy was positive for severe candida esophagitis. Colonoscopy showed multiple superficial ulcers in the transverse colon and terminal ileum with the biopsy negative for IBD. Subsequently he developed fever and watery diarrhea. Stool cultures were positive for MRSA. Blood cultures were obtained which grew MRSA with similar sensitivity pattern as of the gut MRSA. He was successfully treated with IV Vancomycin for MRSA bacteremia. TEE did not show any evidence of endocarditis. Repeat blood and stool cultures were negative. The patient was subsequently discharged with initiation of HAART therapy. HIV/AIDS patients are at increased risk for infections and MRSA is one of the most common pathogens in hospital settings. The common sites of MRSA carriage are nose, throat and rectum. There have not been convincing case reports of gastrointestinal origin of MRSA BSI in the past. However, it has been demonstrated in an immunocompromised mice model that MRSA BSI could be originated from the gut derived bacteria and the proposed mechanism was the migration of bacteria from the intestinal lumen to blood stream. MRSA in the blood from MRSA in the gut could account for a portion of 10-20% of cases when the sources remain unidentified. Early diagnosis and treatment of MRSA infection of GI tract may prevent serious complications including MRSA bacteremia and septic shock in severely immunocompromised patients.