Genomic analysis of Isometamidium Chloride resistance in Trypanosoma congolense

Abstract

Isometamidium Chloride (ISM) is one of the principal drugs used to counteract Trypanosoma congolense infection in livestock, both as a prophylactic as well as a curative treatment. However, numerous cases of ISM resistance have been reported in different African regions, representing a significant constraint in the battle against Animal African Trypanosomiasis.In order to identify genetic signatures associated with ISM resistance in T. congolense, the sensitive strain MSOROM7 was selected for induction of ISM resistance in a murine host. Administered ISM concentrations in immune-suppressed mice were gradually increased from 0.001 mg/kg to 1 mg/kg, the maximal dose used in livestock. As a result, three independent MSOROM7 lines acquired full resistance to this concentration after five months of induction, and retained this full resistant phenotype following a six months period without drug pressure. In contrast, parasites did not acquire ISM resistance in immune-competent animals, even after more than two years under ISM pressure, suggesting that the development of full ISM resistance is strongly enhanced when the host immune response is compromised. Genomic analyses comparing the ISM resistant lines with the parental sensitive line identified shifts in read depth at heterozygous loci in genes coding for different transporters and transmembrane products, and several of these shifts were also found within natural ISM resistant isolates. These findings suggested that the transport and accumulation of ISM inside the resistant parasites may be modified, which was confirmed by flow cytometry and ex vivo ISM uptake assays that showed a decrease in the accumulation of ISM in the resistant parasites.

Integrated genomic and metabolomic profiling of ISC1, an emerging Leishmania donovani population in the Indian subcontinent

“…Variants were annotated with SnpEff v4.1 ( Cingolani et al, 2012 ). SNPs and small indels were considered significantly different between CG and ISC1, when the allele shift difference was at least 0.25 ( Tihon et al, 2017 ) and Mann–Whitney U test p -value <0.05. Allele shifts larger than 0.80 were considered homozygous variants ( Tihon et al, 2017 ).…”

“…SNPs and small indels were considered significantly different between CG and ISC1, when the allele shift difference was at least 0.25 ( Tihon et al, 2017 ) and Mann–Whitney U test p -value <0.05. Allele shifts larger than 0.80 were considered homozygous variants ( Tihon et al, 2017 ). Local copy number variation and chromosomal somy were determined according to Downing et al (2011) .…”

An African Canine Trypanosomosis Case Import: Is There a Possibility of Creating a Secondary Focus of Trypanosoma congolense Infection in France?

“…It occurs especially when the dog is naive for the parasite. Any individual, human or animal, regularly exposed to trypanosomes, seems to develop a trypanotolerance [ 22 , 23 ]. The first signs could be just abatement with anorexia and hyperthermia.…”

Intraspecific Genomic Divergence and Minor Structural Variations in Leishmania (Viannia) panamensis

“…Once the SNPs were identified along the genomes, the allele frequency per chromosome was determined in each sample. Homozygous and heterozygous variant SNPs were determined from allele frequency estimation data, considering as homozygous variants to allele shift of < 0.2 or > 0.80 and as heterozygous variants to allele shifts between 0.2 and 0.8 [40]. Additionally, the SNPs shared between and within the three clades were included in a matrix Excel, which was used to perform the Venn diagram and to represent graphically the SNPs shared in a circular bar plot using an R script.…”

“…The SnpEff program (version v4.1) [25] was used to classify all SNPs based on their functional impact. The SNPs were considered significantly different when the allele shift difference was at least 0.25 [40], with a Mann-Whitney U test p-value of <0.05.…”