Leishmania spp. genetic factors associated with cutaneous leishmaniasis antimony pentavalent drug resistance: a systematic review.

Background: Leishmaniasis is a neglected zoonosis caused by parasites of Leishmania spp. The main drug used to treat cutaneous leishmaniasis (CL) is the antimoniate of meglumine. This drug, which has strong adverse and toxic effects, is usually administered intravenously, further complicating the difficult treatment. Factors such as Leishmania gene expression and genomic mutations appear to play a role in the development of drug resistance.

Objectives: This systematic review summarises the results of the literature evaluating parasite genetic markers possibly associated with resistance to pentavalent antimony in CL.

Methods: This study followed PRISMA guidelines and included articles from PubMed, SciELO, and LILACS databases. Inclusion criteria were studies that (i) investigated mutations in the genome and/or changes in gene expression of Leishmania associated with treatment resistance; (ii) used antimony drugs in the therapy of CL; (iii) used naturally resistant strains isolated from patients. The Joanna Briggs Institute Critical Appraisal Checklist was used to assess article quality and risk of bias.

Findings: A total of 23 articles were selected, of which 18 investigated gene expression and nine genomic mutations. Of these 23 articles, four examined gene expression and genomic mutations in the same samples. Regarding gene expression, genes from the ABC transporter protein family, AQP1, MRPA, TDR1 and TRYR were most frequently associated with drug resistance. In one of the articles in which mutations were investigated, a mutation was found in HSP70 (T579A) and in three articles mutations were found in AQP1 (A516C, G562A and G700A). A limitation of this review is that in most of the included studies, parasites were isolated from cultured lesion samples and drug resistance was assessed using in vitro drug susceptibility testing. These approaches may not be ideal for accurate genetic evaluation and detection of treatment failure.

Main conclusions: The development of further studies to evaluate the genetic resistance factors of Leishmania spp. is necessary to elucidate the mechanisms of the parasite and improve patient treatment and infection control.