Comparative performance evaluation of four commercial multiplex real-time PCR assays for the detection of the diarrhoea-causing protozoa Cryptosporidium hominis/parvum, Giardia duodenalis and Entamoeba histolytica

Abstract

BACKGROUND: Multiplex molecular panels are relentlessly replacing conventional methods for the detection of enteric pathogens from stool samples in clinical and research laboratories. Here we evaluated four commercial multiplex real-time PCR assays for the detection of Cryptosporidium hominis/parvum, Giardia duodenalis and Entamoeba histolytica. METHODS: The diagnostic performance of the Gastroenteritis/Parasite Panel I (Diagenode), the RIDAGENE Parasitic Stool Panel (R-Biopharm), the Allplex Gastrointestinal Parasite Panel 4 (Seegene) and the FTD Stool Parasites (Fast Track) real-time PCR methods was assessed against a reference panel of 126 well-characterized DNA samples including Cryptosporidium hominis (n = 29), Cryptosporidium parvum (n = 3), Giardia duodenalis (n = 47), Entamoeba histolytica (n = 3), other parasite species (n = 20), and apparently healthy subjects (n = 24). PRINCIPAL FINDINGS: Obtained diagnostic sensitivities ranged from 53-88% for Cryptosporidium hominis/parvum, and from 68-100% for G. duodenalis. The R-Biopharm method achieved the best performance for the detection of Cryptosporidium hominis/parvum both in terms of diagnostic sensitivity (87.5%) and detection limit (a 100-fold increase compared to other tests). The Fast Track method was particularly suited for the detection of G. duodenalis, achieving a 100% sensitivity and a detection limit at least 10-fold superior. Detection of E. histolytica was similarly achieved by all compared methods except Diagenode. CONCLUSIONS: Diagnostic performance varied largely depending on the method used and the targeted pathogen species. Factors including test sensitivity/specificity, cost, patient population surveyed, laboratory workflow, and diagnostic algorithm should be carefully considered when choosing the most appropriate multiplex PCR platform.