81. Etiology of Infectious Diarrhea in Patients Tested for Clostridium difficile: If It Isn’t Clostridium difficile, What Is It?
Session: Oral Abstract Session: CDI Prevention
Thursday, October 5, 2017: 9:45 AM
Room: 07AB
Background: The objective of the study was to assay for alternative infectious causes of diarrhea in patients with negative EIA tests for Clostridium difficile.

Methods: A hard-stop alert was implemented at a tertiary care hospital to limit repeat testing for C. difficile within 96 hours of an initial negative EIA. Stool samples from patients with a negative (-) repeat EIA test for C. difficile within 96 hours in the 3 months pre- and post-intervention underwent further evaluation: C. difficile toxigenic culture, GeneXpert C. difficile PCR, Biofire Gastrointestinal (GI) Panel, and culture on a blood agar plate.

Results: Of the 84 C. difficile EIA stool specimens evaluated, 8% were toxigenic culture positive (+), 8% tested + for C. difficile via the Biofire GI panel, and 5 (7%) + with the GenXpert C. difficile PCR (Table 1). 3 of these patients were diagnosed with CDI within 30 days of a + test . 5 patients were + for Norovirus via Biofire GI panel; none were tested for or diagnosed with Norovirus. 2 patients were + for Enteropathogenic E. coli and 1 for Enteroaggregative E. coli via Biofire GI panel; none were tested for or diagnosed with E. coli infection.1 patient was positive for Salmonella and Salmonella was isolated by stool culture.

Conclusion: Patients tested for C. difficile may have alternate causes of diarrhea. When evaluating hospitalized patients with diarrhea, C. difficile, along with alternate causes of diarrhea can be considered.

Table 1: Alternate Infectious Causes of Diarrhea







Biofire GI results


57 (78)

10 (91)


5 (7)a


C. difficile toxin A/B gene

5 (7)

1 (9)

Enteropathogenic E. coli

2 (3)b



1 (1)c


C. difficile tox A/B gene and Rotavirus

1 (1)


Enteroaggregative E. coli

1 (1)b



1 (1)d


C. difficile culture positive

Non-toxigenic C. difficile

2 (3)

2 (18)

Toxigenic C. difficile

5 (7)

2 (18)

GenXpert C.difficile PCR positive

5 (7)


Blood agar plates

Klebsiella oxytoca

1 (1)


Staphylococcus aureus

3 (4)


aNone received clinical diagnosis of Norovirus

bNo clinical enteric culture performed or diagnosis received

cClinical enteric culture performed >30 days post-index stool collection (negative)

dClinical enteric culture in hospital positive for Salmonella

Jennie H. Kwon, DO, MSCI1, Tiffany Hink, BS2, Kimberly Reske, MPH1, Erik R. Dubberke, MD, MSPH3 and Carey-Ann D. Burnham, PhD4, (1)Infectious Diseases, Washington University School of Medicine, St. Louis, MO, (2)Infectious Diseases, Washington University School of Medicine, St Louis, MO, (3)Washington University, St Louis, MO, (4)Pathology and Immunology, Washington University School of Medicine, St. Louis, MO


J. H. Kwon, None

T. Hink, None

K. Reske, None

E. R. Dubberke, Merck: Consultant , Consulting fee
Biofire: one time talk , Speaker honorarium
Alere: one time talk , Speaker honorarium
Sanofi Pasteur: Grant Investigator , Grant recipient
Pfizer: Consultant , Consulting fee
Rebiotix: Investigator , Research support
Rebiotix: Consultant , Consulting fee
valneva: Consultant , Consulting fee

C. A. D. Burnham, bioMerieux: Grant Investigator , Research grant
ThermoFisher: Consultant , Salary
Cepheid: Grant Investigator , Research grant

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