CHICAGO – The course of Clostridium difficile–associated colitis differs considerably among immunosuppressed patients, compared with those who are immunocompetent, results from a German study suggest.
"Besides the known risk factor of antibiotic therapy, immunosuppression must also be regarded as an independent risk factor" for C. difficile-associated infections, Dr. Christoph Lübbert said during a poster session at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
"Immunosuppressive or immmodulatory treatment results in a higher rate of asymptomatic colonization with C. difficile and a minor clinical manifestation (less diarrhea episodes), probably due to the anti-inflammatory effects of steroids in particular. An increasing proportion of symptomatic C. difficile infections, especially in immunosuppressed patients, develops without any history of prior antibiotic treatment."
Between 2005 and 2009, Dr. Lübbert, of the department of medicine at University Hospital, Martin Luther University Halle-Wittenberg, Germany, and his associates evaluated the symptoms and clinical features of 105 inpatients with demonstration of the C. difficile toxin in stool specimens by enzyme immunoassay. Of the 105 patients, 55 were immunosuppressed, which was defined as a neutrophil count of less than 1,000 leukocytes per mL and/or drug immunosuppression by cytostatic agents, glucocorticoids, azathioprine, methotrexate, monoclonal antibodies, and cyclosporin A. The remaining 50 patients in the study were immunocompetent.
Immunosuppressed patients were significantly younger than immunocompetent patients (a mean of 60 vs. 70 years of age, respectively). They were also more likely to be colonized with C. difficile without obvious clinical manifestation of illness (22% vs. 2%), and more likely to relapse (15% vs. 6%).
The researchers also reported that antibiotic use among immunosuppressed patients was 53%, compared with 84% among immunocompetent patients.
"You have to look for C. difficile-associated disease in hospitalized patients on immunosuppressive treatment, even if they don’t take antibiotics," Dr. Lübbert said in an interview at the meeting, which was sponsored by the American Society for Microbiology. "Look for fever, elevated leukocyte count, and for morphologic changes in the intestinal wall. You can have inflammation in the intestine but no significant diarrhea. That is possible."
Dr. Lübbert said that he had no relevant conflicts to disclose.