Dados do Trabalho

Título

Assessing β-tubulin genetic polymorphisms related to benzimidazole derivatives resistance in nematodes infecting livestock

Introdução

Large-scale use of benzimidazole derivatives (BZs) as anthelminthics in livestock and humans is associated with increased resistance. BZs act in the colchicine-sensitive site of β-tubulin in the nematode cytoskeleton, thus inhibiting its polymerization into microtubules. Three single-nucleotide polymorphisms (SNPs) in the β-tubulin gene have been proposed to be associated with resistance of nematodes to BZs. These SNPs generate mutations F167Y, E198A, and F200Y.

Objetivo (s)

To assess the frequency of SNPs related to BZ resistance in different species of nematodes infecting livestock.

Material e Métodos

We performed an in silico analysis in order to detect the mentioned SNPs. β-tubulin locus sequences were recovered from GenBank without restriction of nematode or host species, from 32 regions in Europe, Americas, Asia and Oceania. The BioEdit software v.7.0.5.3 was used to align the sequences and detect the SNPs. Wild- and mutant-types were defined by: i) TTC to TAC in codons 167 and 200, or ii) GAA or GAG to GCA or GCG in codon 198.

Resultados e Conclusão

Seventeen distinct nematode species (Cooperia pectinata, C. punctata, C. oncophora, C. spatulata, Cyathostomum catinatum, Cy. coronatum, Cy. pateratum, Cylicucyclus nassatus, Cyl. radiatus, Cyl. insigne, Cyl. elongatus, Haemonchus placei, H. contortus, Oesophagostomum columbianum, Teladorsagia circumcincta, Trichostrongylus colubriformis, and T. tenuis) were assessed,recovered fromseven differenthost species, which represented sheep, goat, deer, cattle, and horses. For codon 167, 712 sequences were analyzed with the following distribution by genus: Cooperia (n=3), Cyathostomum (n=23), Cylicocyclus (n=16), Haemonchus (n=659), Oesophagostomum (n=1), and Trichostrongylus (n=10). In 52 (7.3%) specimens, the SNP TAC was observed. For codon 200, 872 specimens were analyzed [Cooperia (n=32), Cyathostomum (n=23), Cylicocyclus (n=16), Haemonchus (n=666), Oesophagostomum (n=2), Trichostrongylus (n=52) and Teladorsagia (n=81)], in 247 (28.3%) the SNP TAC was observed. For codon 198, 864 sequences [Cooperia (n=32), Cyathostomum (n=23), Cylicocyclus (n=16), Haemonchus (n=663), Oesophagostomum (n=2), Trichostrongylus (n=52) and Teladorsagia (n=76)] were analyzed. The SNPs GAA or GAG had a frequency of 31 (3.6%). BZ resistance genotypes are frequent in nematodes infecting cattle. The potential spread of BZs resistance should be considered to improve control strategies for livestock parasitic nematodes.

Palavras-chave

BZ-resistance; nematodes; β-tubulin.

Agradecimentos

Faculdade de Farmácia UFJF e PPGCF UFJF