A-286 Performance Evaluation of Molecular Clostridium Difficile Assay using BD MaxTM System

Abstract

Abstract Background Clostridium difficile (C.Diff) is a gram positive anaerobe producing Enterotoxin and Cytotoxin (toxin A and B respectively); toxin B has been reported to be essential for its virulence. It is estimated that C. Diff will cause over half a million infection yearly and one in 11 people over the age of 65 diagnosed with healthcare-associated C.Diff infection die within one month. It is the most common cause of acute diarrhea; residents in Long-Term Care Facilities (LTCF) are more prone to have C. Diff infection (CDI) because of their age, the frequent use of antibiotics, fragilities, co-morbidity, and living environment. Diagnosing CDI is based on clinical signs and symptoms as well as laboratory tests. Several tests available for diagnosing the infection which include: enzyme immunoassays, tissue culture cytotoxicity, anaerobic culture, glutamate dehydrogenase antigen and nucleic acid amplification. The BD MAX™ System is a PCR based assay that provides the sensitivity, specificity and faster turnaround. Methods The MAX™ System is an automated in vitro diagnostic test for the direct qualitative detection of the 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 performed directly on the specimen, utilizing real-time polymerase chain reaction (PCR) for the amplification of C. difficile toxin B gene (tcdB). The test utilizes fluorogenic sequence-specific hybridization probes for detection of the amplified DNA. The test was validated for accuracy, precision, and patient correlation to enzyme-immunoassay using Premier Toxins A & B is an enzyme immunoassay for the direct detection of Clostridium difficile toxin A and toxin B in stool samples. Statistical analyses were done using Analyse-it. Results The percentage agreement for precision, reproducibility, and accuracy were 100%. We had 100% agreement for positive patients on EIA and 85% for negative patients on EIA; however, upon investigation we found the discrepancies were due to false negative EIA results. Conclusion The BD Max gave the benefit of a fully automated with high sensitivity and specificity for the presence of toxin B producing C. Diff. The faster turnaround gives the physician the ability to diagnose CDI and prevent spreading of the disease to other patients. It is very important to remember that C.diff infection can be prevented with appropriate use of antibiotics and implementing antibiotic stewardship and infection control plan to prevent and stop spreading of the infection.