Relationship between increased albendazole systemic exposure and changes in single nucleotide polymorphisms on the β-tubulin isotype 1 encoding gene in Haemonchus contortus

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• 作者：Virginie Barrè ; re^a ; ^{virginie.barrere@mail.mcgill.ca} ; Luis Alvarez^b ; ^c ; ^{lalvarez@vet.unicen.edu.ar} ; Gonzalo Suarez^d ; ^{gsuarez@adinet.com.uy} ; Laura Ceballos^b ; ^c ; ^{ceballos@vet.unicen.edu.ar} ; Laura Moreno^b ; ^c ; ^{lmoreno@vet.unicen.edu.ar} ; Carlos Lanusse^b ; ^c ; ^{clanusse@vet.unicen.edu.ar} ; Roger K. Prichard^a ; ^{roger.prichard@mcgill.ca}
• 关键词：Haemonchus contortus ; Benzimidazole resistance ; Albendazole ; 尾-Tubulin ; Single nucleotide polymorphism ; Pyrosequencing
• 刊名：Veterinary Parasitology
• 出版年：2012
• 期刊代码：107_03044017
• 类别：abs
• 出版时间：25 May, 2012
• 卷：186
• 期：3-4
• 页码：344-349
• 文件大小：318 K

摘要

Resistance to benzimidazole anthelmintics in the nematode Haemonchus contortus has been correlated with single nucleotide polymorphisms (SNPs) on the β-tubulin isotype 1 gene. Three mutations can be used as markers for the detection of resistance, namely SNPs at position 200 and 167 (both TTC to TAC) or at position 198 (GAA to GCA). Harbouring a resistance genotype at any one of these codons can lead to a resistant phenotype. Our objective in this study was to analyse the frequencies of the three mutations when the albendazole dose rate and selection pressure were increased. We used adult H. contortus (males and females) collected directly from the abomasum of untreated lambs, or lambs treated with the manufacturer's recommended dose rate (5 mg/kg), three times the recommended dose rate (15 mg/kg), or nine times the recommended dose rate (45 mg/kg). Anthelmintic efficacy was determined by worm and egg count reductions. For the surviving worms of the four treatment groups, the frequencies of each resistance SNP at codons 167, 200 and 198 were measured using pyrosequencing. Our results showed a strong relationship between an increasing dose rate and an increase in the frequency of the (TAC)₂₀₀ SNP and a decrease in the (TAC)₁₆₇ SNP. All worms genotyped were GAA at codon 198.