Single nucleotide polymorphism (SNP) markers for benzimidazole resistance in veterinary nematodes

Abstract

Resistance to the benzimidazole class of anthelmintics in nematodes of veterinary importance has a long history. Research into the mechanisms responsible for this resistance is subsequently at a more advanced stage than for other classes of anthelmintics. The principal mechanism of resistance to benzimidazoles is likely to involve changes in the primary structure of beta-tubulins, the building blocks of microtubules. Specifically, point mutations in the beta-tubulin isotype 1 gene leading to amino acid substitutions in codons 167, 198, and 200 of the protein have been associated with resistance in nematodes. These single nucleotide polymorphisms offer a means of detecting the presence of resistance within populations. In this mini-review, we focus on the prevalence and importance of these polymorphisms in three groups of nematodes: trichostrongylids, cyathostomins, and hookworms. A brief overview of existing strategies for genotyping single nucleotide polymorphisms is also presented. The CARS initiative hopes to exploit these known polymorphisms to further our understanding of the phenomenon of BZ resistance.

First report of multiple anthelmintic resistance in goat farm in Cuba

“…The prevalence of AR is aggravated by the complexity of the Cuban production systems for small ruminants, where no clear trends toward comprehensive strategies for parasite control have been established and where a single antiparasitic is generally used throughout the year (Delgado-Fernández, 2016). The AS-PCR assay was based on the search for mutations at codon 200 (TTC to TAC) in the gene encoding β-tubulin isotype 1 (Silvestre and Cabaret, 2002;Ghisi et al, 2007;von Samson-Himmelstjerna et al, 2007, Blackhall et al, 2011Barrère et al, 2012). The presence of these mutations in a population causes resistance of the parasites to benzimidazoles.…”

Resistência anti-helmíntica em nematoides gastrintestinais de pequenos ruminantes: avanços e limitações para seu diagnóstico

“…Para a determinação da resistência associada ao códon TAC na posição 200, técnicas de PCR--RFLP (restriction fragment length polymorphism ou polimorfismo de comprimento de fragmentos de restrição) foram desenvolvidas para H. contortus (Tiwari et al 2006) e T. circumcincta (Shayan et al 2007). A técnica de pirosequenciamento também se mostrou rápida e adequada para a detecção múltipla de SNPs (Samson-Himmelstjerna et al 2007). A quantificação dos alelos de resistência/suscetibilidade no DNA extraído de pool de larvas de nematoides pode ser feita usando as técnicas de PCR em tempo real e pirosequenciamento, permitindo uma avaliação sensível, confiável e economicamente acessível do nível de resistên-cia em populações de H. contortus no campo (Höglund et al 2009, Samson-Himmelstjerna et al 2009b.…”

Koyunlarda Haemonchus contortus’un Moleküler Prevalansı, Filogenetik Karakterizasyonu ve Benzimidazol Dirençliliği

“…The broad spectrum anthelmintic drugs including the benzimidazole (BZ) group has been widely used for several years in the control of trichostrongylid nematodes all over the world and as a result anthelmintic resistance began in these parasites [1] . Several molecular techniques especially target the intron l of the ß-tubulin gene of trichostrongylid nematodes including H. contortus have been developed to specifically detect and measure the frequency of the sensitive and resistant alleles for BZ [7,8] . The β-tubulin is highly conserved gene and is found in different trichostrongylid nematodes of small and large ruminants, horses, pigs and also dogs [9] .…”