Recurrent Cystoisospora belli in a patient with HTLV-1 infection

A 31 year old Haitian female presented with acute worsening of chronic diarrhea and weight loss of one year duration. CT of the abdomen showed diffuse mesenteric, pelvic and groin lymphadenopathy. HTLV-1 serology was positive and patient was diagnosed with adult T cell leukemia (ATL) by bone marrow biopsy and flow cytometry. Stool Clostridium difficile (C. difficile) PCR was positive and oral vancomycin was started. Although patient denied any recent antimicrobial exposure, a partial response to treatment suggested that C. difficile was not a colonizer. However after 7 days of treatment the patient continued having more than 10 episodes of watery diarrhea per day. Stool for ova and parasites were initially negative, but subsequent 3 specimens were found to be positive for Cystoisospora belli (Fig. 1). The patient was started on oral trimethoprim/sulfamethoxazole (TMP/SMX) BID and within 2 days the diarrhea resolved. The patient completed 10 days of treatment. Chemotherapy was initiated and after completing the second cycle patient was discharged. Two months after discharge the patient presented again with worsening diarrhea for 2 days. Stool was negative for C. difficile but was positive again for Cystoisospora belli. Patient was restarted on TMP/ SMX. Symptoms resolved completely within a day. The patient was discharged on TMP/SMX prophylaxis 3 times / week as a secondary prophylaxis for Cystoisosporiasis. To our knowledge this case is the first case of a patient with HTLV1 associated leukemia who presented with C. difficile colitis and Cystoisospora belli infection. This case highlights the importance of looking for co-pathogen especially in patients who are immunocompromised who do not respond to treatment of C. difficile colitis. The case raises a question about the need for secondary prophylaxis after an initial episode of infection with Cystoisospora belli in patients with HTLV-1 associated leukemia as these patients are likely to have a recurrence without continuous antimicrobial prophylaxis.