Clostridium difficile dehydrogenase and toxin as a biomarker for monitoring infection in patients with clostridium difficile disease and differentiating carrier state from active disease
Inventors
Boone, James Hunter • Lyerly, David M. • Carman, Robert J.
Assignees
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Publication Number
US-10295535-B2
Publication Date
2019-05-21
Expiration Date
Abstract
Clostridium difficile disease involves a range of clinical presentations ranging from carrier status with other causes of symptoms to mild and self-limiting diarrhea to life-threatening pseudomembranous colitis and megacolon. Cases of C. difficile are treated differently depending on the presence and then the severity of disease. Patients that are carriers may not receive treatment with concern of causing the disease. Mild to moderate cases may be treated with metronidazole while severe and relapsing cases are often treated with vancomycin or fidaxomicin. Current molecular assays are highly sensitive for detecting toxigenic C. difficile and cannot rule out carrier status. Utilization of a biomarker panel that includes C. difficile antigen (GDH), toxins A and B, and fecal lactoferrin allows clinicians to differentiate between a carrier state and active state of C. difficile and allows for monitoring to evaluate the effectiveness of treatment.
Core Innovation
The disclosed invention relates to a method of measuring a quantity of C. difficile in a fecal sample and stratifying C. difficile infection severity while distinguishing carrier status from active C. difficile disease. The method obtains a fecal sample from a patient infected with C. difficile, dilutes the fecal sample, and quantitatively measures the level of C. difficile glutamate dehydrogenase (GDH). Predetermined GDH levels are used to classify whether the patient has a low subclinical quantity indicating a carrier status or a high GDH level indicating active disease.
The invention further uses biomarker patterns to link intestinal inflammation with clinical severity and to support interpretation of outcomes during and after antibiotic treatment. The approach combines quantitative C. difficile antigen (GDH), toxins A/B, and fecal lactoferrin as an indicator of intestinal inflammation. Lactoferrin levels are associated with disease severity, with lactoferrin near baseline used to support carrier state and higher lactoferrin associated with more severe clinical disease.
The disclosed method also supports serial monitoring by describing how biomarker dynamics can indicate cure, reinfection, relapse, and treatment effectiveness. In the reported correlations, lactoferrin returns toward baseline with clinical response, while the presence of GDH and toxins A/B and the relative lactoferrin level are used to differentiate clinical states.
Claims Coverage
The claim set centers on quantitative fecal GDH measurement with predefined GDH thresholds to classify carrier status versus active C. difficile disease and to guide whether antibiotic treatment is withheld or provided. Additional inventive features refine classification by incorporating toxin A/toxin B and fecal lactoferrin, along with assay readouts and antibody contacting/immobilization.
Quantitative fecal GDH threshold-based stratification
A method that obtains a fecal sample, dilutes the sample, and quantitatively measures a level of C. difficile glutamate dehydrogenase (GDH), wherein a low level indicates a low subclinical quantity for carrier status and a high level indicates active disease classification.
Carrier status decision to withhold antibiotics
Determining a patient has a low subclinical quantity of C. difficile indicating a carrier status when the fecal sample has the low level of C. difficile GDH, and withholding antibiotic treatment from the patient determined to have the low subclinical quantity indicating the carrier status.
Active C. difficile disease decision to treat with antibiotics
Determining a patient has active C. difficile disease when the fecal sample has the high level of C. difficile GDH, and treating the patient determined to have active C. difficile disease with antibiotics.
Toxin presence and fecal lactoferrin refinement for classification
Detecting whether toxin A or toxin B is present in a fecal sample and measuring the level of fecal lactoferrin in the same fecal sample.
Withholding antibiotics for carrier status with lactoferrin cutoff and toxin absence
For carrier-status determination, withholding antibiotic treatment when the fecal sample has a low subclinical quantity indicated by low GDH and further comprises a fecal lactoferrin level of about 7.25 µg/ng or less and no toxin A or toxin B present.
Active disease determination requiring lactoferrin elevation and toxin presence
For active-disease determination from a fecal sample with a high level of C. difficile GDH, requiring fecal lactoferrin greater than 7.25 µg/ng and toxin A or toxin B present.
GDH quantification by optical density readout
Determining that the optical density of a readable enzyme-linked antibody bound sample at a specified wavelength corresponds to the level of C. difficile GDH in the sample.
GDH antibody contacting using immobilized antibodies
Contacting a fecal sample with immobilized polyclonal or monoclonal antibodies to C. difficile GDH to form an antibody-bound sample.
The inventive coverage centers on quantitative fecal GDH measurement with predefined GDH thresholds to classify carrier status versus active C. difficile disease and to guide whether antibiotic treatment is withheld or provided. Dependent features refine classification by incorporating toxin A/toxin B presence or absence and fecal lactoferrin levels, and by specifying assay readouts and antibody-based contacting/immobilization for GDH measurement.
Stated Advantages
Stratifies C. difficile infection severity and distinguishes carrier status from active C. difficile disease.
Supports determining whether to withhold antibiotic treatment or to treat with antibiotics based on measured biomarker levels.
Improves clinical state interpretation by combining GDH with toxin A/toxin B and fecal lactoferrin linked to intestinal inflammation and disease severity.
Enables monitoring of biomarker dynamics during and after antibiotic treatment to indicate cure, reinfection, relapse, and treatment effectiveness.
Documented Applications
Risk stratification of Clostridium difficile infection severity to distinguish carrier state from active C. difficile disease.
Clinical interpretation during and after antibiotics, including determining outcomes such as clinical cure, reinfection, relapse/clinical recurrence, and treatment effectiveness.
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