A multiplex PCR for the simultaneous detection and genotyping of the Echinococcus granulosus complex

PLoS Negl Trop Dis. 2013;7(1):e2017. doi: 10.1371/journal.pntd.0002017. Epub 2013 Jan 17.

Abstract

Echinococcus granulosus is characterized by high intra-specific variability (genotypes G1-G10) and according to the new molecular phylogeny of the genus Echinococcus, the E. granulosus complex has been divided into E. granulosus sensu stricto (G1-G3), E. equinus (G4), E. ortleppi (G5), and E. canadensis (G6-G10). The molecular characterization of E. granulosus isolates is fundamental to understand the spatio-temporal epidemiology of this complex in many endemic areas with the simultaneous occurrence of different Echinococcus species and genotypes. To simplify the genotyping of the E. granulosus complex we developed a single-tube multiplex PCR (mPCR) allowing three levels of discrimination: (i) Echinococcus genus, (ii) E. granulosus complex in common, and (iii) the specific genotype within the E. granulosus complex. The methodology was established with known DNA samples of the different strains/genotypes, confirmed on 42 already genotyped samples (Spain: 22 and Bulgaria: 20) and then successfully applied on 153 unknown samples (Tunisia: 114, Algeria: 26 and Argentina: 13). The sensitivity threshold of the mPCR was found to be 5 ng Echinoccoccus DNA in a mixture of up to 1 µg of foreign DNA and the specificity was 100% when template DNA from closely related members of the genus Taenia was used. Additionally to DNA samples, the mPCR can be carried out directly on boiled hydatid fluid or on alkaline-lysed frozen or fixed protoscoleces, thus avoiding classical DNA extractions. However, when using Echinococcus eggs obtained from fecal samples of infected dogs, the sensitivity of the mPCR was low (<40%). Thus, except for copro analysis, the mPCR described here has a high potential for a worldwide application in large-scale molecular epidemiological studies on the Echinococcus genus.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Animals
  • Child
  • Child, Preschool
  • Dogs
  • Echinococcosis / epidemiology*
  • Echinococcosis / parasitology
  • Echinococcosis / veterinary*
  • Echinococcus granulosus / classification*
  • Echinococcus granulosus / genetics
  • Echinococcus granulosus / isolation & purification*
  • Humans
  • Molecular Diagnostic Techniques / methods*
  • Molecular Epidemiology / methods
  • Multiplex Polymerase Chain Reaction / methods*
  • Parasitology / methods*

Grants and funding

This work was supported by the UNESCO-L'OREAL international “For women in science” Fellowships (http://www.unesco.org/), the Swiss National Science Foundation, grant no. NF1003A-12590-1 (http://www.snf.ch/), the SCOPES program of the Swiss National Scientific Foundation, grant no. IB74BO-110928 (http://www.snf.ch/E/international/europe/scopes/Pages/default.aspx), the Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), Argentina, grant: PICT 2010 N° 2252 (http://www.agencia.mincyt.gov.ar/), the Estonian Ministry of Education and Sciences, target financing project SF0180122s08 (www.hm.ee/), the Estonian Science Foundation, grant 8525 (www.etf.ee/) and the European Union through the European Regional Development Fund, Centre of Excellence FIBIR (http://moritz.botany.ut.ee/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.