Mutation Characteristics and Phylogenetic Analysis of Five Leishmania Clinical Isolates

Simple Summary Leishmaniasis, a neglected tropical disease, is caused by infection with the Leishmania species, threatening millions of people in approximately 100 endemic countries. The emergence of antimony-resistant Leishmania strains have brought difficulties to the treatment and elimination of leishmaniasis. This study performed genome-wide resequencing and phylogenetic analysis of five isolates from the Leishmania donovani complex, focusing on finding mutations related to antimony resistance and virulence of the newly isolated Leishmania strain L_HCZ in 2016. By combining whole-genome sequencing and whole-genome phylogenetic analysis, Leishmania isolates L_801, L_9044 and L_Liu were identified as Leishmania donovani, and L_HCZ as Leishmania infantum. By discovering genome-wide single-nucleotide polymorphisms and structural variations, we identified mutations of drug resistance-related genes in the antimony-resistant Leishmania isolate L_HCZ. The new Leishmania isolate L_HCZ has strong virulence and strong drug resistance, which should be taken seriously by the relevant health departments and scientific researchers. Leishmaniasis is a neglected tropical disease threatening millions of people worldwide. The emergence of antimony-resistant Leishmania strains have brought difficulties to the treatment and elimination of leishmaniasis. This study performed genome sequencing, phylogenetic analysis and mutation analysis of five Leishmania clinical isolates, especially the Leishmania strain L_HCZ isolated in 2016, which shows strong virulence and antimony resistance. By phylogenetic analysis, four isolates (L_DD8, L_801, L_Liu and L_9044) were identified as Leishmania donovani, the isolate L_HCZ was identified as Leishmania infantum and the isolate L_DD8 as a standard strain of L.donovani. Genome-wide mutation analysis was applied to identify mutations related to the drug resistance and virulence of the newly isolated L_HCZ. Compared with the other four Leishmania isolates, L_HCZ had the most mutations in genes associated with antimony resistance, including the ABC transporter, ascorbate-dependent peroxidase, gamma-glutamylcysteine synthetase, glucose-6-phosphate 1-dehydrogenase, ATP-binding cassette protein subfamily A and multi-drug resistance protein-like genes. Among the genes associated with virulence, L_HCZ had the most mutations in cysteine peptidase A, cysteine peptidase B, cysteine peptidase C, heat-shock protein 70, gp63, acid phosphatase, kinesin k39, kinesin, phosphoglycan beta 1, amastin-like surface protein and amastin-like proteins. The mutations in L_HCZ might possibly contribute to its antimony resistance and strong virulence in clinical patients. Whole-genome resequencing has exhibited broad application prospects and may be put into clinical use in the future for parasite identifying and epidemiological investigations.

Automated summary

Leishmaniasis is a neglected tropical disease that threatens millions of people worldwide. The emergence of antimony-resistant Leishmania strains has posed challenges to the treatment and elimination of leishmaniasis. In this study, genome sequencing, phylogenetic analysis, and mutation analysis were performed on five clinical isolates of Leishmania, with a focus on the newly isolated L_HCZ strain in 2016, which showed strong virulence and antimony resistance.