Added value of multiplex Luminex Gastrointestinal Pathogen Panel (xTAG® GPP) testing in the diagnosis of infectious gastroenteritis.

The Luminex Gastrointestinal Pathogen Panel (xTAG(®) GPP) detects in one assay the most common gastroenteritis-causing pathogens and toxins, namely adenovirus 40/41, norovirus genogroup (NG) I/II, rotavirus A, Clostridium difficile toxin A/B, Campylobacter sp., Escherichia coli O157, Enterotoxigenic E. coli heat-labile enterotoxin/heat-stable enterotoxin, Salmonella sp., Shiga-toxin producing E. coli, Shiga-like toxin (Stx)1/2, Shigella sp., Vibrio cholerae, Yersinia enterocolitica, Cryptosporidium sp., Entamoeba histolytica and Giardia sp. In this study, we compared the results that were obtained by testing 393 faecal samples, collected during November and December 2011 at our laboratory, using the xTAG(®) GPP assay with the results of the routine diagnostic procedure. This procedure includes culture for bacteria and real-time PCR for viruses and parasites, but only if the test was requested by the clinician. If the clinician did not request the test for an xTAG(®) GPP-positive target, real-time PCR assays were used to confirm xTAG(®) GPP positivity. Discrepant results were also tested with real-time PCR assays. A total of 83 targets were detected in 76 samples using xTAG(®) GPP. The xTAG(®) GPP assay detected 43 additional positives compared with the routine diagnostic procedure, of which 11 targets could not be confirmed by real-time PCR. The non-confirmed targets were Campylobacter (one sample), Salmonella (four samples), Shigella (one sample) and E. histolytica (five samples). The xTAG(®) GPP was shown to be a convenient and sensitive assay for detection of 15 major gastrointestinal pathogens in a single molecular test, but for detection of E. histolytica and Salmonella, a confirmatory assay is indicated.