1367. Hospitalwide Asymptomatic and Symptomatic Clostridium difficile (CD) Infection (CDI) Surveillance by Realtime PCR
Session: Poster Abstract Session: Clostridium difficile
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
  • IDWeek 2013.pdf (262.4 kB)
  • Background: CDI is the leading, definable cause of healthcare-associated diarrhea.  Molecular PCR assays for toxigenic genes are increasingly being utilized for CDI detection.

    Objective: To evaluate the prevalence of asymptomatic and symptomatic CDI at a university hospital using a realtime PCR assay.

    Methods: All adult patients present in a large, university hospital in Houston, Texas during 4 days were screened for enrollment. Subjects provided stool specimens or rectal swabs and completed a questionnaire. Fecal specimens were tested by realtime PCR for toxin A and B genes and ELISA for toxins A and B (Wampole). Confirmation of realtime PCR results by selective, anaerobic (CCFA) culture and conventional PCR for toxin genes for morphologically consistent isolates was performed.

    Results: 199 (53%) of 375 patients were enrolled from January 8-11, 2013. 103 (52%) of 199 study participants provided a stool sample or rectal swab. Overall, 12% of subjects reported diarrhea at enrollment. CD was detected by PCR in 18 (17%) of 103 subjects who provided a fecal sample, including 4 symptomatic and 14 asymptomatic subjects. Among CD-positive subjects, the one symptomatic (CDI) patient tested was positive versus 3/13 (23%) asymptomatic CDI (AsCDI) patients positive by ELISA. Previous hospitalization or residence in a healthcare facility, antibiotic or antacid receipt, or history of previous CDI was not associated with development of CDI or AsCDI. Considering detection of AsCDI as a false positive, the positive predictive value of the realtime PCR assay is 22%.

    Conclusion: The mean monthly CD detection rate at this university hospital increased significantly from 13.4 per 10,000 patient days (95% CI, 11.6 to 15.1) to 27.0 per 10,000 patient days (95% CI, 23.9 to 30.1; p<0.001) after changing from cell cytoxocity assay to realtime PCR for CDI diagnosis. However, in the setting of low diarrhea prevalence (12%), relatively frequent asymptomatic CDI (14%), and infrequent symptomatic CDI (4%), the positive predictive value of the PCR assay is poor and may be contributing to significant asymptomatic CDI detection at this hospital. An adjunct test to realtime PCR such as an ELISA for toxin production or a fecal test for inflammation may be necessary to confirm that CD is causing symptomatic disease.

    Hoonmo L. Koo, MD1, John Van, BA2, Meina Zhao, PhD2, Xunyan Ye, PhD2, Zhi-Dong Jiang3, Carolyn Grimes, DrPH, BSMT (ASCP)4, Diana C. Koo, MPA5, Todd M. Lasco, PhD6, Margaret Price, PHD7, Kevin Garey, PharmD8 and Herbert Dupont, MD, FIDSA3,9,10, (1)Baylor College of Medicine, University of Texas-Houston School of Public Health, Houston, TX, (2)Baylor College of Medicine, Houston, TX, (3)Center for Infectious Diseases, The University of Texas, School of Public Health, Houston, TX, (4)University of Texas School of Public Health, Houston, TX, (5)University of Texas-Houston School of Public Health, Houston, TX, (6)Clinical Laboratory, St Lukes Episcopal Hospital, Houston, TX, (7)St. Luke's Episcopal Hospital, Houston, TX, (8)University of Houston College of Pharmacy, Houston, TX, (9)St. Luke's Episcopal Hospital and Kelsey Research Foundation and Kelsey-Seybold Clinic, Houston, TX, (10)Section of Infectious Diseases, Baylor College of Medicine, Houston, TX


    H. L. Koo, None

    J. Van, None

    M. Zhao, None

    X. Ye, None

    Z. D. Jiang, None

    C. Grimes, None

    D. C. Koo, None

    T. M. Lasco, None

    M. Price, None

    K. Garey, None

    H. Dupont, None

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