Real-time multiplex PCR for human echinococcosis and differential diagnosis

Abstract

Molecular identification of rare human infectious pathogens appears to be one of the most relevant current methods for rapid diagnosis and management of patients. PCR techniques, in particular real-time quantitative PCR, are best suited for the detection of DNA from the pathogens, even at low concentrations. Echinococcosis infections are due to helminths of the Echinococcus genus, with closely related species involved in parasitic lesions affecting animals and, accidentally, humans. We developed a multiplex qPCR (MLX qPCR) assay allowing for the detection of four Echinococcus species involved in Europe in alveolar echinococcosis (AE) and cystic echinococcosis (CE) (Echinococcus multilocularis, E. granulosus sensu stricto, E. ortleppi, and E. canadensis), based on short mitochondrial targets. A collection of 81 fresh and formalin-fixed paraffin-embedded tissues (FFPE) of AE and CE lesions was assembled. The qPCR assays were performed in triplex for Echinococcus spp. detection, associated with a qPCR inhibitor control. A duplex qPCR was also designed to enable diagnosis of two other dead-end helminthiases (cysticercosis (Taenia solium), and toxocariasis (Toxocara cati and T. canis)). The sensitivity of the qPCR was assessed and ranged from 1 to 5 × 10−4 ng/μL (seven PCR assays positive), corresponding to 37–42 cycles for quantifiable DNA. The specificity was 100% for all the targets. This multiplex qPCR, adapted to low amounts of DNA can be implemented in the laboratory for the rapid molecular diagnosis of Echinococcosis species.