Assessment of three DNA extraction kits for the absolute quantification of strongyle nematode eggs in faecal samples

BACKGROUND: Haemonchus contortus is one of the most pathogenic gastrointestinal nematodes of small ruminants. The current diagnostic approach for the detection of this species relies on coproscopic methods, which both have low sensitivity and are time consuming. Methods employing detection through DNA amplification, such as droplet digital polymerase chain reaction (ddPCR), offer an advantageous approach to the diagnosis of H. contortus. However, DNA extraction protocols need to be constantly updated for the optimal retrieval of diagnostically usable template. Here, we describe the evaluation of three genomic DNA extraction kits for the detection and quantification of H. contortus ITS2 amplicon DNA from faecal samples, using droplet digital PCR. RESULTS: DNA samples, extracted from faecal material with the Nucleospin DNA Stool kit, produced the highest amounts of ITS2 amplicon copies and had the lowest coefficient of variation across different dilutions and sample types (fresh or frozen) out of the tested kits (Nucleospin DNA Stool, E.Z.N.A.(®) Stool DNA Kit and QIAamp Fast DNA Stool Mini Kit). Furthermore, the protocol of this kit has the fewest number of steps and the price of DNA extraction per sample is reasonable (2.77 €). CONCLUSIONS: The Nucleospin DNA Stool kit is an attractive option for the detection and quantification of H. contortus DNA in faecal samples of small ruminants in a diagnostic setting.