Background: Clostridium difficile (CD) is one of the most common healthcare associated infections (HAIs). While the gold standard for diagnosis of CD is cytotoxicity assay and toxigenic culture, there are a number of molecular assays for rapid CD detection. This study evaluated the performance of an in-house TEM-PCR GI panel with the Cepheid Xpert C. difficile/Epi assay using clinical samples collected in hospital setting.
Methods: Stool samples of patients with suspected CD infections were tested by TEM-PCR GI panel and with Cepheid Xpert assay. CD detection is the part of the Diatherix multiplex GI panel which can simultaneously detect 3 viral, 7 bacterial, 2 protozoan, and 3 toxins in a single specimen. The Cepheid assay detects the toxin B gene and the O27/NAP1/B1 strain. Two TaqMan assays targeting the toxin B and tpi gene were developed as an alternative approach for confirmation of discrepant results. Demographics data, risk factors, and other clinically relevant information was obtained for this study.
Results: We enrolled 36 patients with mean age of 67 years (TaqMan assays done in 31). 53% females. Known risk factors included: recurrent CD infection (17%), recent antibiotic use (56%), recent hospitalization (53%), proton pump inhibitor use (44%), gastrointestinal disorders (31%) and immunosuppression (19%). 22% of specimens were not tested by Cepheid PCR as stool was formed. There was 100% concordance between TEM-PCR CD toxin B, Taqman tpi gene, and Cepheid Xpert. Cepheid NAP1/B1 was positive in 8% of patients. TEM-PCR detected positive binary toxin in 38% of patients. All NAP1/B1 positive specimens were positive for binary toxin with TEM-PCR. 13% of patients with positive CD by TEM-PCR had co-detection of other targets (25% Norovirus, 50% Rotavirus and 25% EPEC). Those patients with co-detection, 80% were female and more than 55 years old. Other stool studies done in 67% of patients, 42% had occult blood with 87% positive, 42% had cultures with 7% positive for Gram positive cocci and 22% had O&P (All were negative)
Conclusion: The performance of TEM-PCR GI panel was comparable to Cepheid assay for CD detection. Further studies are needed to asses the clinical utility of TEM-PCR GI panel to detect multiple pathogens and how this information can be used to improve patient care.
F. Ibrahim, None
E. Grigorenko, Diatherix lab: Investigator , Salary
S. Brzezinski, Diatherix lab: Employee , Salary
D. Stalons, Diatherix Lab: Investigator , Salary
A. Hassoun, None
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