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Genome-wide mutagenesis and multi-drug resistance in American trypanosomes induced by the front-line drug benznidazole.

ABSTRACT: Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects 5-8 million people in Latin America. Although the nitroheterocyclic compound benznidazole has been the front-line drug for several decades, treatment failures are common. Benznidazole is a pro-drug and is bio-activated within the parasite by the mitochondrial nitroreductase TcNTR-1, leading to the generation of reactive metabolites that have trypanocidal activity. To better assess drug action and resistance, we sequenced the genomes of T. cruzi Y strain (35.5?Mb) and three benznidazole-resistant clones derived from a single drug-selected population. This revealed the genome-wide accumulation of mutations in the resistant parasites, in addition to variations in DNA copy-number. We observed mutations in DNA repair genes, linked with increased susceptibility to DNA alkylating and inter-strand cross-linking agents. Stop-codon-generating mutations in TcNTR-1 were associated with cross-resistance to other nitroheterocyclic drugs. Unexpectedly, the clones were also highly resistant to the ergosterol biosynthesis inhibitor posaconazole, a drug proposed for use against T. cruzi infections, in combination with benznidazole. Our findings therefore identify the highly mutagenic activity of benznidazole metabolites in T. cruzi, demonstrate that this can result in multi-drug resistance, and indicate that vigilance will be required if benznidazole is used in combination therapy.

SUBMITTER: Campos MC

PROVIDER: S-EPMC5663738 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

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Genome-wide mutagenesis and multi-drug resistance in American trypanosomes induced by the front-line drug benznidazole.

Campos Mônica C MC Phelan Jody J Francisco Amanda F AF Taylor Martin C MC Lewis Michael D MD Pain Arnab A Clark Taane G TG Kelly John M JM

Scientific reports 20171031 1

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects 5-8 million people in Latin America. Although the nitroheterocyclic compound benznidazole has been the front-line drug for several decades, treatment failures are common. Benznidazole is a pro-drug and is bio-activated within the parasite by the mitochondrial nitroreductase TcNTR-1, leading to the generation of reactive metabolites that have trypanocidal activity. To better assess drug action and resistance, we sequ ...[more]

PMID: 29089615

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Project description:First-line antiretroviral therapy (ART) failure often results from the development of resistance-associated mutations (RAMs). Three patterns, including thymidine analogue mutations (TAMs), 69 Insertion (69Ins) and the Q151M complex, are associated with resistance to multiple-nucleoside reverse transcriptase inhibitors (NRTIs) and may compromise treatment options for second-line ART.We investigated patterns and factors associated with multi-NRTI RAMs at first-line failure in patients from The TREAT Asia Studies to Evaluate Resistance - Monitoring study (TASER-M), and evaluated their impact on virological responses at 12 months after switching to second-line ART. RAMs were compared with the IAS-USA 2013 mutations list. We defined multi-NRTI RAMs as the presence of either Q151M; 69Ins; ? 2 TAMs; or M184V+? 1 TAM. Virological suppression was defined as viral load (VL) <400 copies/ml at 12 months from switch to second-line. Logistic regression was used to analyze (1) factors associated with multi-NRTI RAMs at first-line failure and (2) factors associated with virological suppression after 12 months on second-line.A total of 105 patients from 10 sites in Thailand, Hong Kong, Indonesia, Malaysia and Philippines were included. There were 97/105 (92%) patients harbouring ? 1 RAMs at first-line failure, 39/105 with multi-NRTI RAMs: six with Q151M; 24 with ? 2 TAMs; and 32 with M184V+? 1 TAM. Factors associated with multi-NRTI RAMs were CD4 ? 200 cells/µL at genotyping (OR=4.43, 95% CI [1.59-12.37], p=0.004) and ART duration >2 years (OR=6.25, 95% CI [2.39-16.36], p<0.001). Among 87/105 patients with available VL at 12 months after switch to second-line ART, virological suppression was achieved in 85%. The median genotypic susceptibility score (GSS) for the second-line regimen was 2.00. Patients with ART adherence ? 95% were more likely to be virologically suppressed (OR=9.33, 95% CI (2.43-35.81), p=0.001). Measures of patient resistance to second-line ART, including the GSS, were not significantly associated with virological outcome.Multi-NRTI RAMs at first-line failure were associated with low CD4 level and longer duration of ART. With many patients switching to highly susceptible regimens, good adherence was still crucial in achieving virological response. This emphasizes the importance of continued adherence counselling well into second-line therapy.

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Dataset Information

Genome-wide mutagenesis and multi-drug resistance in American trypanosomes induced by the front-line drug benznidazole.

Publications

Genome-wide mutagenesis and multi-drug resistance in American trypanosomes induced by the front-line drug benznidazole.

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