GENEOHM

BD GeneOhm™ Line of Products

BD GeneOhm™ Cdiff Assay

The BD GeneOhm™ Cdiff assay is a qualitative in vitro diagnostic test for the rapid detection of C. difficile toxin B gene (tcdB) in human liquid or soft stool specimens from patients suspected of having Clostridium difficile infection (CDI). The test is based on real-time PCR and is intended for use as an aid in diagnosis of CDI. The BD GeneOhm™ Cdiff assay is the first diagnostic method to combine speed, sensitivity and specificity in a single method and provides definitive results that can be trusted for the detection of the C. difficile toxin B gene (tcdB) direct from patient samples. Quickly reaching a definitive diagnosis can ensure that CDI patients get the proper treatment without delay.(1) CDI patients can be placed in isolation sooner to reduce transmission and prevent outbreaks.(1,2) Definitive results can help reduce inappropriate antimicrobial use in negative patients, which is consistent with antimicrobial stewardship guidelines.(3)

CDI: Increasing Problem for Healthcare Institutions
Clostridium difficile is a gram-positive, spore-forming anaerobic bacillus, first linked to disease in 1978, when it was identified as the causative agent of pseudomembranous colitis. Transmission occurs primarily in healthcare facilities.(4) It is the most common cause of antimicrobial-associated diarrhea(5) and it is the first organism suspected when a hospitalized patient develops diarrhea.(6) C. difficile is also the most common infectious cause of acute diarrheal illness in long-term care facilities.(4)

There are an estimated 500,000 cases of CDI per year. In 2005, the number of deaths in U.S. hospitalized patients exceeded 28,000 and 9.5% of patients with CDI died during their hospital stay.(7) The financial and clinical burden of diarrhea due to C. difficile is significant, with estimated hospital costs in excess of $1 billion annually.(8) The epidemiology of CDI has been changing with increases in both disease incidence and severity. Patients with CDI had an increased length of stay in the hospital of nearly three fold and increased mortality in the hospital of approximately 4.5 fold.(4) Transmission to patients occurs primarily via the hands of healthcare personnel or from contact with a contaminated environment.

Diagnosis of CDI
A case of CDI is diagnosed with a combination of clinical, physical and laboratory findings. Current laboratory testing for detection of toxigenic C. difficile lacks a single method that is sensitive, specific and rapid. This leads to missed CDI cases and delayed diagnosis. Repeat testing is often performed in patients whose symptoms continue despite a negative test result. These patients are treated empirically in the absence of a definitive diagnosis, which can lead to unnecessary use of antibiotics in patients who are actually not infected with C. difficile.

Diagnosis of CDI also impacts infection control and Antimicrobial Stewardship programs. Preemptive isolation of patients based on clinical suspicion (i.e. diarrhea) leads to isolation of patients who do not have CDI. Since physicians may not trust a negative EIA result, these patients may remain in isolation unnecessarily. Institutions that isolate only laboratory-confirmed cases of CDI may be missing positive patients (due to low sensitivity of current EIA test methods) that should be isolated. Lack of trust in negative results can also lead to empiric treatment being continued despite negative test results, and therefore overuse of antimicrobials.

Improving Patient Management
Real-time PCR is a new solution because it combines speed and accuracy in a single test. Detection of the toxin B gene (tcdB), found only in toxigenic C. difficile, has good correlation with clinical disease in symptomatic patients.(9)

The BD GeneOhm™ Cdiff assay(10) is a real-time PCR method for the rapid detection of toxin B gene (tcdB) direct from stool samples. It is more sensitive than cytotoxicity and can be performed in the same time frame as an immunoassay, which can help physicians quickly reach a definitive diagnosis with one rapid, same-day test result. Use of this new PCR method may help avoid repeat testing, multi-method algorithms and complicated reporting of results.

Definitive diagnosis of CDI eliminates delays in the treatment of infected patients aimed at reducing the potentially severe outcomes of CDI.(11) CDI-confirmed patients can be placed in isolation sooner to reduce transmission and prevent outbreaks of CDI.(12) Definitively ruling out CDI can help avoid empiric treatment and unnecessary exposure to antibiotics in negative patients. This allows the physician to focus on other causes of patient symptoms and avoid unnecessary isolation of negative patients.

Let us show you how BD GeneOhm™ Cdiff can help improve diagnosis of CDI in your facility.

Cdiff Assay Performance

References

1. Kuijpers et al., Clin Microbiol Infect 2006; 12(Suppl. 6):2-18
2. McFarland et al., AJIC 2007; 35:237-253
3. Dellit et al., Clinical Infectious Diseases 2007; 44:159-77
4. Sunenshine RH and McDonald LC., Cleveland Clin J Med 2006; 73:187-97
5. Blossom and McDonald, Clin Infect Dis 2007; 45:222-7
6. Wilkins TD and Lyerly DM., J Clin Microbiol 2003; 41:531-4
7. Elixhauser and Jhung, AHRQ Statistical Brief #50 April 2008
8. Dubberke ER et al., Clin Infect Dis 2008; 46:497-504
9. Peterson et al., Clin Infect Dis 2007; 45:1152-60
10. BD GeneOhm™ Cdiff Package Insert
11. Kuijpers et al., Clin Microbiol Infect 2006; 12 (Suppl. 6): 2-18
12. McFarland et al., AJIC 2007; 35:237-253