Methods and Compositions for the Detection of Functional Clostridium Difficile Toxins


Market and Background:

In recent years, Clostridium difficile has emerged as a new “superbug”, rivaling MRSA in both frequency and severity. C. difficile infection is now the most common definable cause of hospital-acquired and antibiotic-associated diarrhea in the United States, with over 500,000 cases reported annually. Morbidity and mortality resulting from C. difficile-associated diseases are at historically high levels, with 14,000 deaths per year occurring in the U.S. alone. Pathogenic strains of C. difficile produce two toxins, which are essential for C. difficile pathogenesis. Only strains that produce active toxin are able to cause disease. Despite the fact that disease is caused by the activity of bacterial toxin, most diagnostic assays do not test for functional toxin.


Over 2,000,000 diagnostic tests for C. difficile are performed each year in the U.S. Current clinical diagnosis of C. difficile infection is performed using one or more of the following techniques: PCR, ELISA, stool culture, or a tissue culture cytotoxicity assay.  In most cases at least two of these techniques must be performed in sequence in order to achieve an accurate diagnosis.  The most commonly used methods of diagnosis are the PCR assay and the ELISA. The ELISA is fast but has low accuracy and an additional diagnostic method must be performed for confirmation of the diagnosis. PCR is able to quickly and accurately detect the presence of the toxin genes in the bacterial genome, but is unable to detect functional toxin. Our researchers found that almost 75% of C. difficile that do not actually produce functional disease-causing toxin would test positive for toxin by PCR analysis. Currently there is no single test commercially available that can accurately detect active toxin-producing C. difficile in combination with a rapid turnaround time and low cost. 


The Technology: Dr. Herbert DuPont and colleagues at UTHealth have developed a quantitative C. difficile activity assay that enables cost-efficient, sensitive, quantitative measurement of the cleavage activities of toxin A and toxin B of C. difficile in both a culture supernatant and a selective and differential agar-based assay. The plate assay enables identification of toxin-producing C. difficile without the need for additional toxin-confirmatory tests by taking advantage of unique cleavage characteristics of the toxins to differentiate activity simultaneously with detection.


UTHealth Ref. No.: 2010-0058

Inventors: Dr. Herbert L. DuPont, Charles Darkoh, Dr. Heidi B. Kaplan

Patent Status: Patent pending

License Available: world-wide; exclusive or non-exclusive


Patent Information:

The preceding is intended to be a non-confidential and limited description of a novel technology created at the University of Texas Health Science Center at Houston (UTHealth). This promotional material is not comprehensive in scope and should not replace company’s diligence in a thorough evaluation of the technology. Please contact the Office of Technology Management for more information regarding this technology.
For Information, Contact:
Hannah Nelson
Senior Technology License Associate
University of Texas Health Science Center At Houston
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