1218. Is Clostridium difficile Strain Type a Predictor of Disease Outcomes?
Session: Oral Abstract Session: New Insights into C. difficile Transmission and Reporting
Saturday, October 5, 2013: 9:45 AM
Room: The Moscone Center: 200-212
Background: Increases in morbidity and mortality of Clostridium difficile infection (CDI) have been attributed to the emergence of the fluoroquinolone-resistant North American pulsed-field gel electrophoresis type 1 (NAP1) strain, but some recent studies have not supported this hypothesis.  We describe strain types causing CDI and evaluate their association with outcomes.

Methods: We analyzed data from 8 geographic areas in the United States participating in active population-based CDI surveillance.  A case was defined as a C. difficile-positive stool by either toxin or molecular assay during 2009–2011 in a surveillance area resident at least one year of age without a positive test in the prior eight weeks.  A convenience sample of case isolates underwent strain typing.  We performed logistic regression to calculate adjusted odds ratios (aOR) and confidence intervals (CI) to assess associations of strain type with three separate outcomes of interest: severe disease (defined as ileus, toxic megacolon, or pseudomembranous colitis after positive test; or white blood cell count ≥15,000/mm3 within one day of positive test), severe outcome (intensive care unit admission after positive test, colectomy for C. difficile infection, or death within 30 days of positive test), and death within 14 days of positive test.

Results: Strain typing results were available for 2,149 cases.  Severe disease occurred in 372 (17.3%) cases, severe outcome in 108 (5.0%), and death within 14 days in 58 (2.7%).  The most common strain type was NAP1 (28.2%), followed by NAP4 (9.6%) and NAP11 (8.8%).  NAP1 was associated with greater odds of severe disease compared to other strains; CDI from the NAP1 strain was also associated with older age, healthcare exposures, prior antibiotic use, and patient comorbidities in unadjusted analysis.  After controlling for these risk factors, NAP1 remained associated with severe disease (aOR 1.81, 95% CI, 1.42-2.31), severe outcome (aOR 1.58, 95% CI, 1.05-2.37), and death within 14 days (aOR 1.94, 95% CI, 1.13-3.33).

Conclusion: From a large, geographically diverse dataset, the NAP1 strain accounted for over one quarter of cases and was a predictor of severe disease, severe outcome, and death.  Strain-specific strategies, such as antibiotic stewardship to reduce fluoroquinolone use, may be needed to reduce NAP1 prevalence.

Isaac See, MD1, Yi Mu, PhD1, Jessica Cohen, MPH1,2, Zintars G. Beldavs, MS3, Lisa G Winston, MD4, Ghinwa Dumyati, MD, FSHEA5, John Dunn, DVM, PhD6, Monica M. Farley, MD7, Stacy Holzbauer, DVM, MPH, DACVPM8, Carol Lyons, MPH9, Helen Johnston, MPH10, Erin Phipps, DVM11, Rebecca Perlmutter, MPH12, Lydia Anderson, BS1 and Fernanda Lessa, MD1, (1)Centers for Disease Control and Prevention, Atlanta, GA, (2)Atlanta Research and Education Foundation, Atlanta, GA, (3)Oregon Health Authority, Portland, OR, (4)University of California, San Francisco/San Francisco General Hospital, San Francisco, CA, (5)University of Rochester, Rochester, NY, (6)Tennessee Department of Health, Nashville, TN, (7)Emory University and Atlanta Veterans Administration Medical Center, Atlanta, GA, (8)CDC, St. Paul, MN, (9)Connecticut EIP, New Haven, CT, (10)Colorado Department of Public Health and Environment, Denver, CO, (11)New Mexico Emerging Infections Program, Albuquerque, NM, (12)Maryland Dept. of Health and Mental Hygiene, Baltimore, MD

Disclosures:

I. See, None

Y. Mu, None

J. Cohen, None

Z. G. Beldavs, None

L. G. Winston, None

G. Dumyati, None

J. Dunn, None

M. M. Farley, None

S. Holzbauer, None

C. Lyons, None

H. Johnston, None

E. Phipps, None

R. Perlmutter, None

L. Anderson, None

F. Lessa, None

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