2026-04-13T16:54:56Zhttps://recercat.cat/oai/requestoai:recercat.cat:2445/1836132025-12-05T00:50:11Zcom_2072_1057col_2072_478917
RECERCAT
author
Martínez Valladares, María
author
Valderas García, Elora
author
Gandasegui, Javier
author
Skuce, Philip
author
Morrison, Alison
author
Castilla Gómez de Agüero, Verónica
author
Cambra Pellejà, Maria
author
Balaña Fouce, Rafael
author
Rojo Vázquez, Francisco A.
2022-03-01T08:24:28Z2022-03-01T08:24:28Z20202022-02-25T19:00:39Z
BACKGROUND NlmCategory: BACKGROUND content:
"Benzimidazole resistance is associated with isotype-1
\xCE\xB2-tubulin gene F200Y, E198A and F167Y SNPs. In this
study, the recently described polymorphism E198L was reported
and analysed in Teladorsagia circumcincta." - Label: METHODS
NlmCategory: METHODS content: "The benzimidazole phenotypic
resistance was measured by the faecal egg count reduction test
(FECRT) and the egg hatch test (EHT) using a discriminating dose
(DD) in 39 sheep flocks. Around 1000 larvae collected before and
after treatment were used for DNA extraction. The resistant
species identified in all flocks was T. circumcincta. The
resistance alleles frequencies were measured for F200Y and
E198A. A 371-bp fragment of the isotype-1 \xCE\xB2-tubulin gene
was analysed, including the three codons of interest, and a new
pyrosequencing assay was designed for testing E198L." - Label:
RESULTS NlmCategory: RESULTS content: "The percentage of
resistant flocks was 35% by FECRT or 26% by EHT; however, F200Y
and E198A SNPs were absent in T. circumcincta. The amplification
of a 371-bp fragment confirmed the absence of F167Y and F200Y in
6 resistant flocks. Regarding codon 198, all samples after
treatment carried a leucine (CTA). A pyrosequencing assay
analysed the allele frequencies for the first two bases at codon
198 independently, G/C and A/T. The correlation between C and T
frequencies was almost 1 (r\xE2\x80\x89=\xE2\x80\x890.929,
P\xE2\x80\x89<\xE2\x80\x890.0001) and the mean value of both
was calculated to measure the leucine frequency; this value
ranged between 10.4-80.7% before treatment, and 82.3-92.8% after
treatment. High and similar correlations were reported between
the genotypic variables (C frequency, T frequency or mean of
both frequencies) and phenotypic resistance
(r\xE2\x80\x89>\xE2\x80\x890.720,
P\xE2\x80\x89<\xE2\x80\x890.0001), although negatively
associated with the FECRT and positively with the EHT. According
to multivariate linear regression analysis, the T frequency was
the most significant variable influencing the phenotypic
resistance (FECRT or EHT; P\xE2\x80\x89<\xE2\x80\x890.0001).
In the EHT, 67.1% of the phenotypic variability is associated
with the T frequency but in the FECRT only 33.4%; therefore, the
EHT using a DD seems to detect the genotypic resistance more
accurately than the FECRT." - Label: CONCLUSIONS NlmCategory:
CONCLUSIONS content: The E198L polymorphism can confer BZ
resistance on its own in T. circumcincta.
cc by (c) Martínez Valladares, María et al, 2020 http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess
Benzimidazoles
Resistència als medicaments
Benzimidazoles
Drug resistance
Teladorsagia circumcincta beta tubulin: the presence of the
E198L polymorphism on its own is associated with benzimidazole
resistance.
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion