Standardisation and validation of an in-house quantitative real-time polymerase chain reaction (qPCR) assay for the diagnosis of Clostridioides difficile infection

Objectives: Clostridioides difficile is an emerging enteric pathogen that causes nosocomial diarrhoea in adults. The excessive cost of commercial molecular tests restricts the access of developing countries to its diagnosis. This study aimed to develop and validate in-house quantitative polymerase chain reaction (qPCR) targeting the C. difficile toxin B gene (tcdB) using two detection methodologies-SYBR Green and hydrolysis probes-for the diagnosis of C. difficile infection (CDI).Methods: Glutamate dehydrogenase (GDH) plus toxigenic culture was the standard reference diagnostic method. The SYBR Green method and hydrolysis probes were used to study 392 samples simultaneously to assess the diagnostic value of these real-time PCR assays in detecting CDI from clinical samples.Results: The SYBR Green and hydrolysis probe assays showed 97.9% and 87.5% sensitivity; 99.1% and 100.0% specificity; 94.0% and 100.0% positive predictive value; 99.7% and 98.3% negative predictive value; and 99.0% and 98.5% accuracy, respectively. Conclusions: The two qPCR methodologies evaluated could offer an adequate tool as part of an algorithm in the laboratory diagnosis of CDI.