Background: Clostridium difficile infection (CDI) impacts significantly on the management of cancer patients by delaying treatment or by increasing morbidity and mortality. Early and reliable test results are important for the diagnosis and treatment of CDI. We aim to examine and compare the results of our C.difficile testing algorithm with the results from the reference laboratory to determine whether our results are giving the clinicians an accurate indication of the presence of toxigenic C.difficile.
Methods: At Peter MacCallum Cancer Centre in Melbourne, Victoria, a glutamate dehydrogenase (GDH) antigen screening assay (Immunocard® C. difficile GDH, Meridian Bioscience, Inc.) is performed on all semi-formed and liquid stool samples. All positive GDH antigen samples are then tested for toxin A and B genes (tcdA and tcdB) by loop-mediated isothermal DNA amplification (LAMP) testing (Illumigene, Meridian Bioscience, Inc) and also cultured (Chrom ID C.difficile agar, bioMerieux). The faeces sample or C.difficile isolate (if grown) are then sent to the reference laboratory for molecular testing, regardless of the toxin gene LAMP result.
Results: Over a seven month period (May –November 2013), a total of 24 positive GDH antigen samples were detected. Of these, 21 (88%) were concordant and 3 (12%) were non-concordant with reference laboratory results.
Conclusion: Preliminary data indicates that early and reliable results are available for clinicians at our cancer centre. Long term observation and more data are required to determine if results remain consistent.