Whole genome sequencing of multiple Leishmania donovani clinical isolates provides insights into population structure and mechanisms of drug resistance

Leishmania species are protozoan parasites that are transmitted by a bite from a sandfly. These parasites are found in 88 countries and infect an estimated 12 million people worldwide. Genome sequencing of certain Leishmania species has been, but not on Leishmania donovani even though it is considered the most important Leishmania species in public health. Attempts to eliminate L. donovani from India have become a more difficult task due to drug resistant strains of L. donovani emerging. This study done by Downing et al. (2011) was performed to better understand L. donovani genome to enhance public health intervention strategies.

A high-quality draft of Leishmania donovani genome was created based off of isolates of             L. donovani collected from 17 infected patients. The reference genome was used to map out natural variation data. After generating the genome sequences for each of the 17 parasite sample, genome-wide single-nucleotide polymorphisms (SNPs) and structural variation (SV) were revealed and genes with differential patterns in antimonial resistant and susceptible samples were recognized. The variation of SNPs was limited in parasite strains that were antimonial resistant (Downing et al. 2011).

This study showed that there is a correlation between genome-wide single-nucleotide polymorphisms and drug-resistant strains of Leishmania donovani. More sensitive and powerful approaches to observing genomic diversity should be performed in order to further research L. donovani and other Leishmania species’ drug resistance and how genomes are correlated (Downing et al. 2011).

This article relates to the study by Guevara et al. (1994) “Presence of Leishmania braziliensis in blood samples from cured patients or at different stages of immunotherapy” because Guevara et al (1994) studied the presence of a Leishmania species in humans after being treated for the infection and Downing et al. (2011) researched how drug resistance in Leishmania species is correlated with genome.

Citation

T. Downing, H. Imamura, S. Decuypere, T. Clark, G. Coombs, J. Cotton, J. Hilley, S. Doncker, I. Maes, J. Mottram, M. Quail, S. Rijal, M. Sanders, G. Schonian, O. Stark, S. Sundar, M. Vanaerschot, C. Hertz-Fowler, J. Dujardin, M. Berriman, 2011, Whole genome sequencing of multiple Leishmania donovani clinical isolates provides insights into population structure and mechanisms of drug resistance, Genome Research, 21: 2143-2156

-Kaitlin Smith