Methods: We enrolled 50 subjects, 23 immunocompetent (NH) and 27 immunocompromised (IC) patients with acute symptoms of CDI and a positive stool C. diff PCR test (first episode or first recurrence). IC patients were neutropenic (11; 6 with hematologic or lymphoreticular CA), stem cell (5; 3 were also neutropenic) or solid organ transplant recipients (10), and patients on immunosuppressives (6; 2 were also neutropenic), including concomitant chemotherapy and high-dose corticosteroids. Aliquots of positive stool specimens are collected and filtrates prepared. Stool filtrates are serially diluted and the amount of cytotoxic activity determined using a tissue-culture cytotoxin assay. Age, WBC count, Cr, albumin, and number of bowel movements (BM) per day were also recorded.
Results: A higher proportion of patients in the IC group had C. difficile toxin titers > 1:1,280 compared to NH patients (63 % vs 30 %, p = 0.02). We did post hoc analysis of the differences between groups by LSD showed that, the only IC group that contributed to the differences between groups were patients with neutropenia (mean titer 3,785 +/- 1,984 vs 1,598 +/- 2,371 for the NH group). Patients with neutropenia were more likely to be on concomitant antibiotics.
Conclusion: The C. difficile cytotoxin titers in stool of IC patients were significantly higher compared to NH patients, but this was driven by higher titers in patients with neutropenia and not other immunocompromised groups. Patients with neutropenia were more likely to be receiving concomitant antibiotics than NH patients, solid organ transplant recipients, and other IC patients. This indicates the severity of disease in neutropenic patients is due to antibiotic pressure rather than a poor host response to C. difficile colitis.
R. Estes, None
N. Pettit, None
L. Petty, None
K. Mullane, MERCK: Consultant and Investigator , Consulting fee and Research support
Rebiotics: Investigator , Research support
Summit: Investigator , Research support
Seres: Investigator , Research support
Viropharma -Shire: Investigator , Research support
Novartis: Investigator , Research support
Actelion: Investigator , Research support
D. Pitrak, Gilead: Grant Investigator , Grant recipient
ViroPharma: Grant Investigator , Grant recipient and Research grant
Merck: Grant Investigator , Grant recipient and Research grant