2081. Tests for Inflammation (Stool and Blood) and Stool Spore Density Correlate Better with C. difficile Infection (CDI) (tcdB and Toxin Positive Samples) than the Number of Stools per Day
Session: Poster Abstract Session: Clostridium difficile: Outcomes, Testing, Prevention
Saturday, October 29, 2016
Room: Poster Hall
Posters
  • IDweek2016 poster-JB-10 12 16LP.pdf (468.8 kB)
  • Background: Distinguishing between C. difficile colonization vs. infection (CDI) is difficult and requires a combination of laboratory tests and clinical criteria. PCR is a highly sensitive test that is commonly used to diagnose toxigenic CDI. However, results from several recent studies raise the question of whether PCR is overly sensitive. Our hypothesis was that selected laboratory tests could be used to distinguish between colonized and infected patients who were PCR positive for toxigenic C. difficile.

    Methods: Patients that submitted an unformed stool sample for CDI testing between 10/1/12 and 9/30/13 and had a positive test by PCR (Cepheid) were included in the study. Interviews were conducted for the number of stools per day (BM/D) and charts were reviewed for relevant clinical data. Stool samples were sent frozen to TechLab for additional testing including cell cytotoxicity for TcdB, quantitative toxigenic bacterial culture, PCR-ribotyping, and quantitative fecal lactoferrin and glutamate dehydrogenase (GDH) by immunoassay.

    Results:  A total of 215 PCR-positive patients were included with a mean age of 71 years. Stools per day separated patients into groups with <3 BM/D (26%), 3 to 10 BM/D (57%), and >10 BM/D (17%). Further testing showed that 55% of patients were cell cytotoxicity positive and 90% were toxigenic culture positive. Spore counts ranged from 102 to 108 CFU/g stool. Ribotype 027 was detected in 23% of patients. Stool toxin-positive patients had lower Ct (p=1x10-19), higher WBC (p=1x10-6), higher counts (p=1.8x10-16), more lactoferrin (p=1x10-6), and higher GDH concentrations (p=4.6x10-18). Interestingly, the number of stools per day did not correlate with microbiological or clinical indicators of CDI even when patients on a laxative and antidiarrheal (50%) agents were removed.

    Conclusion: Patients who had lower Ct, higher spore counts, and positive stool toxin by cell cytotoxicity were associated with significantly increased levels of fecal lactoferrin and blood WBC; however, the number of stools per day did not correlate with worse inflammatory markers. Additional studies are needed to both determine the utility of stools per day as a criteria in diagnosing CDI and also determine if these markers can help define clinical CDI.

    James Boone, MS, TechLab, Inc., Blacksburg, VA, Becky Smith, MD, Infectious Diseases, Pritzker School of Medicine, University of Chicago, Chicago, IL, Robert Carman, PhD, Techlab, Inc., Blacksburg, VA, David Persing, MD, PhD, Cepheid, Sunnyvale, CA and Lance Peterson, MD, FIDSA, FSHEA, Pritzker School of Medicine, University of Chicago, Chicago, IL

    Disclosures:

    J. Boone, TechLab: Employee , Salary

    B. Smith, None

    R. Carman, TechLab: Employee , Salary

    D. Persing, Cepheid: Employee , Salary

    L. Peterson, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.