Terminal ileitis secondary to Mycobacterium gordonae in a renal transplant

In recent years, solid-organ transplantation has witnessed enhanced patient and graft survival secondary to the development of new immunosuppressive agents. Therefore, infectious complications, including atypical infections (e.g., nontuberculous mycobacteria [NTM]), remain problematic in this population (1). The following report is of a renal transplant recipient who developed symptomatic terminal ileitis secondary to infection by Mycobacteriumgordonae. A 35-year-old man with renal failure secondary to hypertensive nephropathy underwent a living-related kidney transplant. His postoperative course was uneventful, and his immunosuppressive regimen at discharge consisted of tacrolimus, mycophenolate mofetil, and prednisone. Seven months posttransplant, he presented with complaints of low-grade fevers and postprandial abdominal pain. He denied nausea, vomiting, or diarrhea. His renal function remained at baseline. An abdominal computed tomography scan demonstrated an abnormal, thickened segment of terminal ileum. Colonoscopy revealed multiple nodules, exudate, erythema, and edema without ulceration in the distal terminal ileum. Histopathologic examination revealed ulceration with acute and chronically inflamed granulation tissue. Gram staining, acid-fast staining, and viral immunohistology were negative. Stool cultures demonstrated M.gordonae. The patient was empirically treated with 300 mg per day of isoniazid, 600 mg per day of rifampin, 900 mg per day of ethambutol, and 50 mg per day of vitamin B-6 for 6 weeks. He was maintained on his current immunosuppressive regimen. The patient showed complete resolution of symptoms on this antibiotic regimen. Three months after completion of the antibiotic course, the patient demonstrated a return of mild postprandial discomfort. Stool cultures and colonoscopy were repeated. Biopsies of the terminal ileum did not show any pathologic condition. Although cultures of the stool remained positive for mycobacterium, his symptoms resolved without another course of antimycobacterial agents. In recent years, NTM have been increasingly identified as pathogens in the immunocompromised patient (1). Because many of the NTM are ubiquitous, distinguishing between colonization and active infection is difficult. Treatment is often begun empirically while waiting for cultures or histopathologic specimens. Clinical infections typically respond to standard antimycobacterial therapy, although the duration of treatment has not been well defined (2). Intestinal involvement by NTM is a rare entity in solid-organ transplantation. Our review of the literature demonstrates only four cases of intestinal NTM infections (one heart, one liver, and two kidney transplants) (1,3–5), none involving the terminal ileum. In three of these cases, the diagnosis was performed on the basis of the presence of acid-fast bacilli on staining alone. In the fourth case, Mycobacterium avium was isolated. Two of the four cases responded to antimycobacterial therapy with resolution of their symptoms; two patients died from unrelated illnesses before receiving treatment. This case of terminal ileitis secondary to M. gordonae infection represents an unusual presentation of an NTM infection in a renal transplant recipient. Although systemic NTM infections occur relatively infrequently, they are associated with significant morbidity. Fortunately, case reports indicate a good clinical response to standard antimycobacterial therapy (2). This experience with M. gordonae as an intestinal pathogen emphasizes the need for the transplant specialist to consider atypical mycobacterium as the cause of nonspecific systemic complaints. Heather B. Neuman, MD Ken A. Andreoni, MD Mark W. Johnson, MD Jeff H. Fair, MD David A.