916. Risk Factors for Community-Associated Clostridium Difficile Infection: a Case Control Study
Session: Poster Abstract Session: Clostridium difficile Infections: Epidemiology and Diagnostics
Friday, October 9, 2015
Room: Poster Hall
Background: Community-associated Clostridium difficile infection (CA-CDI) represents 35% of all CDI cases based on U.S. population-based data, but risk factors are poorly described. We conducted a matched case-control study to identify CA-CDI risk factors.

Methods: We used population-based CA-CDI surveillance data from 10 Emerging Infection Program (EIP) sites to identify eligible case-patients ≥18 years of age with a positive C. difficile specimen (toxin or molecular assay) collected as an outpatient or within 3 days of hospitalization who did not have a prior positive specimen or a documented overnight stay in a healthcare facility in the 12 weeks prior to specimen collection. For each case-patient, one control was randomly selected from a commercial database of landline telephone numbers in EIP catchment areas after matching on 10-year age bands and gender. Data were obtained from a telephone interview for cases and controls to assess exposures in the 12 weeks prior to the illness onset in the case-patient. Conditional logistic regression with stepwise selection was used to identify independent CA-CDI predictors.

Results: A total of 226 matched pairs were enrolled. Seventy percent were female, and 52.2% were >60 years of age.  Results of the multivariable model are shown in the table. Among cases, the most common reasons for taking antibiotics (n=158) were reported to be: ear/upper respiratory infection (19.6%), skin/soft tissue infection (17.1%), and dental surgery (13.9%). Of 191 antibiotics reported by cases, 47.1% were taken within 2 weeks of illness onset.

Conclusion:  Antibiotics remain a large driver of CA-CDI, and stewardship should focus on outpatient prescribing. Prescribing practices in dental settings should also be examined. Proton pump inhibitors and trazodone should be examined for potential adverse impacts on the microbiome. Outpatient medical settings are a potentially important understudied environmental source of CA-CDI.    

Table:Independent Risk factors within 12 weeks of CA-CDI

Independent Risk Factor

Adjusted OR

95% Confidence Limit


White race


1.7 - 14.0


Chronic renal failure


1.7 - 549.2


Antibiotic use


6.8 - 34.1


Received outpatient medical care


1.2 - 5.1


Proton pump inhibitor use


1.1 - 4.2


Trazodone use


3.1 - 482.1


Susan N. Hocevar, MD1, Sandra N. Bulens, MPH1, Monica Farley, MD, FIDSA2, Stacy Holzbauer, DVM, MPH, DACVPM3, Emily B. Hancock, MS4, Ghinwa Dumyati, MD, FSHEA5, Corinne M. Davis, MPH6, Carol Lyons, MPH7, Rebecca Perlmutter, MPH8, Erin Parker, MPH9, Claire Reisenauer, DVM10, Valerie L.S. Ocampo, RN, MIPH11, Yi Mu, PhD1 and L. Clifford Mcdonald, MD, FSHEA1, (1)Centers for Disease Control and Prevention, Atlanta, GA, (2)4Atlanta Veteran Affairs Medical Center, Atlanta, GA, (3)Minnesota Department of Health, St. Paul, MN, (4)Emerging Infections Program, University of New Mexico, Albuquerque, NM, (5)University of Rochester Medical Center, Rochester, NY, (6)Tennessee Department of Health, Nashville, TN, (7)Connecticut Emerging Infections Program, New Haven, CT, (8)Maryland Department of Health and Mental Hygiene, Baltimore, MD, (9)California Emerging Infections Program, Oakland, CA, (10)Colorado Department of Public Health and Environment, Denver, CO, (11)Oregon Health Authority, Portland, OR


S. N. Hocevar, None

S. N. Bulens, None

M. Farley, None

S. Holzbauer, None

E. B. Hancock, None

G. Dumyati, None

C. M. Davis, None

C. Lyons, None

R. Perlmutter, None

E. Parker, None

C. Reisenauer, None

V. L. S. Ocampo, None

Y. Mu, None

L. C. Mcdonald, None

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