RT info:eu-repo/semantics/article
T1 Quantification of resistant alleles in the β-tubulin gene of field strains of gastrointestinal nematodes and their relation with the faecal egg count reduction test
A1 Esteban Ballesteros, Myriam
A1 Rojo Vázquez, Francisco Antonio
A1 Skuce, Philip
A1 Melville, Lynsey
A1 González Lanza, María del Camino
A1 Martínez Valladares, María
A2 Sanidad Animal
K1 Veterinaria
K1 Sheep
K1 Teladorsagia circumcincta
K1 Trichostrongylus colubriformis
K1 Anthelmintic resistance
K1 FECRT
K1 Single nucleotide polymorphism
K1 Beta-tubulin
K1 Pyrosequencing
K1 3109 Ciencias Veterinarias
K1 2401.12 Parasitología Animal
K1 3104.07 Ovinos
AB [EN]Background: Benzimidazole (BZ) resistance in gastrointestinal nematodes is associated with a single nucleotide polymorphism (SNP) at codons 167, 198 and 200 in the isotype 1 of beta-tubulin gene although in some species these SNPs have also been associated with resistance to macrocyclic lactones. In the present study we compared the levels of resistance in Teladorsagia circumcincta and Trichostrongylus colubriformis by means of the faecal egg reduction test (FECRT) and the percentage of resistant alleles obtained after pyrosequencing. The study was conducted in 10 naturally infected sheep flocks. Each flock was divided into three groups: i) group treated with albendazole (ABZ); ii) group treated with ivermectin (IVM); iii) untreated group. The number of eggs excreted per gram of faeces was estimated at day 0 and 14 post-treatment. Results: Resistance to ABZ was observed in 12.5% (1/8) of the flocks and to IVM in 44.4% (4/9) of them. One flock was resistant to both drugs according to FECRT. Coprocultures were performed at the same dates to collect L3 for DNA extraction from pooled larvae and to determine the resistant allele frequencies by pyrosequencing analysis. In T. circumcincta, SNPs were not found at any of the three codons before treatment; after the administration of ABZ, SNPs were present only in two different flocks, one of them with a frequency of 23.8% at SNP 167, and the other 13.2% % at SNP 198. In relation to T. colubriformis, we found the SNP200 before treatment in 33.3% (3/9) of the flocks with values between 48.5 and 87.8%. After treatment with ABZ and IVM, the prevalence of this SNP increased to 75 and 100% of the flocks, with a mean frequency of 95.1% and 82.6%, respectively. Conclusion: The frequencies observed for SNP200 in T. colubriformis indicate that the presence of resistance is more common than revealed by the FECRT.
PB BMC
LK https://hdl.handle.net/10612/19863
UL https://hdl.handle.net/10612/19863
NO Esteban Ballesteros, M., Rojo-Vázquez, F. A., Skuce, P. J., Melville, L., González Lanza, C., & Martínez Valladares, M. (2017). Quantification of resistant alleles in the β-tubulin gene of field strains of gastrointestinal nematodes and their relation with the faecal egg count reduction test. BMC Veterinary Research, 13, Article e71. https://doi.org/10.1186/S12917-017-0992-9
NO © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
DS BULERIA. Repositorio Institucional de la Universidad de León
RD 21-may-2024