Selecting a multiplex PCR panel for accurate molecular diagnosis of intestinal protists: a comparative study of Allplex® (Seegene®), G-DiaParaTrio (Diagenode®), and RIDA®GENE (R-Biopharm®) assays and microscopic examination.

Commercial multiplex PCR assay panels were developed to overcome the limitations of microscopic examination for parasitological diagnosis on stool samples. However, given the increased supply of this diagnostic approach, these assays must be evaluated to position them in a diagnostic algorithm. Analytical performances of the multiplex PCR assay G-DiaParaTrio, Allplex® GI parasite and RIDA®GENE parasitic stool panel for detecting Blastocystis sp., Entamoeba histolytica, Giardia duodenalis, Cryptosporidium spp., Dientamoeba fragilis, and Cyclospora cayetanensis, were assessed through a retrospective comparative study on 184 stool samples initially sent for parasitological investigation. The composite reference method for parasitological diagnosis was microscopic observation and Entamoeba histolytica-specific adhesion detection when necessary. Multiplex PCR assays were performed on extracted DNA from each stool, following the manufacturer's recommendations. Discrepant results with the composite reference method were investigated with species-specific PCR to approach a final parasitological diagnosis. Overall sensitivity/specificity for the multiplex PCR assays was 93.2%/100% for G-DiaParaTrio, 96.5%/98.3% for Allplex® GI parasite and 89.6%/98.3% for RIDA®GENE, whereas the composite reference method presented an overall sensitivity/specificity of 59.6%/99.8%. These results confirmed the added diagnostic value of the multiplex PCR approach for gastrointestinal protists. Nevertheless, the PCR procedure and the analytical performance for each protist of interest, variable depending on the multiplex PCR assay, must be considered when implementing a PCR-based diagnostic approach.

TITLE: Sélection d'un panel PCR multiplex pour un diagnostic moléculaire précis des protistes intestinaux : étude comparative des tests Allplex® (Seegene®), G-DiaParaTrio (Diagenode®) et RIDA®GENE (R-Biopharm®) et de l'examen microscopique. ABSTRACT: Des panels commerciaux de tests PCR multiplex ont été développés pour dépasser les limites de l'examen microscopique pour l'examen parasitologique des selles. Cependant, compte tenu de l'offre croissante de cette approche diagnostique, ces tests doivent être évalués pour les positionner dans un algorithme de diagnostic. Les performances analytiques des tests PCR multiplex G-DiaParaTrio, Allplex® GI parasite et RIDA®GENE parasitic stool panel pour la détection de Blastocystis sp., Entamoeba histolytica, Giardia duodenalis, Cryptosporidium spp., Dientamoeba fragilis et Cyclospora cayetanensis, ont été évaluées à travers une étude comparative rétrospective sur 184 échantillons de selles envoyés initialement pour un examen parasitologique. La méthode composite de référence pour le diagnostic parasitologique était l'observation microscopique et la détection d'adhérence spécifique d'Entamoeba histolytica lorsque cela était nécessaire. Des tests PCR multiplex ont été effectués sur l'ADN extrait de chaque selle conformément aux recommandations du fabricant. Les résultats discordants avec la méthode de référence composite ont été étudiés par PCR spécifique d'espèce pour approcher un diagnostic parasitologique final. La sensibilité/spécificité globale des tests PCR multiplex est respectivement de 93,2 %/100 % pour G-DiaParaTrio, 96,5 %/98,3 % pour Allplex® GI et 89,6 %/98,3 % pour RIDA® GENE alors que la méthode de référence composite présente une sensibilité/spécificité globale de 59,6 %/99,8 %. Ces résultats ont confirmé la valeur diagnostique ajoutée de l'approche PCR multiplex pour les protistes gastro-intestinaux. Néanmoins, la procédure de PCR et les performances analytiques pour chaque protiste d'intérêt, variables selon les tests PCR multiplex, doivent être prises en compte lors de la mise en œuvre d'une approche de diagnostic basée sur la PCR.

Assessment of the first commercial multiplex PCR kit (ParaGENIE Crypto-Micro Real-Time PCR) for the detection of Cryptosporidium spp., Enterocytozoon bieneusi, and Encephalitozoon intestinalis from fecal samples.

Cryptosporidium spp. Enterocytozoon bieneusi and Encephalitozoon intestinalis are opportunistic pathogens responsible for gastrointestinal diseases. We evaluated the ParaGENIE Crypto-Micro Real-Time PCR kit (Ademtech, France), the first CE-IVD compliant PCR assay available for these pathogens. This study was conducted blindly against a reference panel of 115 stool specimens including positive samples for Cryptosporidium spp. (n = 48) and E. bieneusi (n = 38) as well as negative or positive samples for other parasites to test for cross-reactivity. An additional set of samples corresponding to 8 rare Cryptosporidium species was also included. Discrepancies were evaluated with external in-house PCR tests. The ParaGENIE Crypto-Micro PCR assay displayed a sensitivity/specificity of 91.7%/100% and 97.3%/98.7% for Cryptosporidium spp. and E. bieneusi, respectively, and was able to detect all 12 Cryptosporidium species of the reference panel, including rare species. This new CE-IVD assay will facilitate the diagnosis of intestinal cryptosporidiosis and microsporidiosis, a major concern in immunocompromised patients and travelers.

Rapid diagnostic tests relying on antigen detection from stool as an efficient point of care testing strategy for giardiasis and cryptosporidiosis? Evaluation of a new immunochromatographic duplex assay.

Microscopy is the gold standard for the diagnosis of gastrointestinal parasites but is time-consuming and dependent on operator skills. Rapid diagnostic tests represent alternative methods but most evaluations have been conducted on a limited number of samples preventing their implementation in the clinical setting. We evaluated a new CE-IVD marked immunochromatographic assay (Crypto/Giardia K-SeT®, Coris Bioconcept) for the detection of G. intestinalis and Cryptosporidium spp. in 2 phases (retrospective and prospective) on a set of 482 stool samples including rare Cryptosporidium species. Besides G. intestinalis, this test could represent a rapid and reliable alternative to the modified Ziehl-Neelsen staining for the diagnosis of cryptosporidiosis (sensitivity/specificity were 89.2%/99.3% and 86.7%/100% for G. intestinalis and Cryptosporidium resp.), reducing diagnostic delays. Such strategy would also be time-saving by avoiding wet mount microscopy and concentrations steps, being particularly appropriate for laboratories having little expertise in microscopy or not able to implement molecular diagnostic methods.