Multilocus characterization and phylogenetic analysis of Leishmania siamensis isolated from autochthonous visceral leishmaniasis cases, southern Thailand

Abstract

BackgroundVisceral leishmaniasis (VL) caused by Leishmania siamensis is an emerging disease continuously reported in six southern provinces of Thailand. To date, the phylogenetic relationships among Leishmania isolates from Thai patients and other Leishmania species are still unclear and the taxonomic diversity needs to be established. In this study, the phylogenetic inference trees were constructed based on four genetic loci (i.e., SSU-rRNA, ITS1, hsp70, and cyt b), using DNA sequences obtained from autochthonous VL patients from southern Thailand and reference sequences of reported Leishmania isolates from other studies deposited in GenBank.ResultsPhylogenetic analyses of hsp70 and cyt b loci supported a clade comprised of L. siamensis isolates, which is independent to the other members in the genus Leishmania. In combination with genetic distance analysis, sequence polymorphisms were observed among L. siamensis isolates and two different lineages could be differentiated, lineages PG and TR. Phylogenetic analysis of the cyt b gene further showed that L. siamensis lineage TR is closely related to L. enrietti, a parasite of guinea pigs.ConclusionThe finding of this study sheds further light on the relationships of L. siamensis, both in intra- and inter-species aspects. This information would be useful for further in-depth studies on the biological properties of this important parasite.

Disseminated Autochthonous Dermal Leishmaniasis Caused by Leishmania siamensis (PCM2 Trang) in a Patient from Central Thailand Infected with Human Immunodeficiency Virus

“…In 2013, Leelayoova and others discovered that the so-called L. siamensis has indeed two separate lineages: the TR lineage and PG lineage. 9 Further works by Pothirat and others clarified using sequence analysis that a novel isolate from northern Thailand LSCM1 (accession no. JX898938) and all other strains except PCM2 Trang were L. martiniquensis (PG lineage), as previously stated from the Martinique island.…”

“…[10][11][12][13] ITS-1 region is the most variable marker that can be used to analyze the genetic difference among Leishmania species. 9 The clinical manifestations of novel leishmaniasis in Thailand can be categorized into three clinical forms: visceral, diffused cutaneous, and diffused cutaneous combined with visceral. 14 The infection has been mostly reported in immunocompromised patients, particularly those with HIV infection.…”

“…Therefore, another PCR and DNA sequencing were performed using primer specific to Leishmania for its identification. 6,9 Sequences from two independent loci were examined: the ITS-1 region of the 18S ribosomal RNA gene and the large subunit of RNAPolII. The large subunit of RNAPolII sequences of our parasite appeared to be 1,181/1,184 base pairs (99%) identical to L. siamensis previously reported (GenBank accession no.…”

Leishmaniasis in Thailand: A Review of Causative Agents and Situations

“…These isolates were reported as two lineages of L. siamensis: lineage PG and TR. 10 The results of 15 isoenzyme analyses revealed two distinct species. The first lineage, L. siamensis lineage PG (MHOM/TH/2011/PG), was identical to the zymodeme MON-229 of L. martiniquensis (MHOM/MQ/92/MAR1).…”

“…MARTINIQUENSIS AND LEISHMANIA (LEISHMANIA) SIAMENSIS With regard to species identification, two axenic cultured promastigote isolates from two VL patients 10 were sent for isoenzyme analysis at the French Reference Center on Leishmaniasis, Montpellier, France. These isolates were reported as two lineages of L. siamensis: lineage PG and TR.…”