Heterogeneity of Molecular Resistance Patterns in Antimony-Resistant Field Isolates of Leishmania Species from the Western Mediterranean Area

Abstract

h Antimonials remain the first-line treatment for the various manifestations of leishmaniasis in most areas where the disease is endemic, and increasing cases of therapeutic failure associated with parasite resistance have been reported. In this study, we assessed the molecular status of 47 clinical isolates of Leishmania causing visceral and cutaneous leishmaniasis from Algeria, Tunisia, and southern France. In total, we examined 14 genes that have been shown to exhibit significant variations in DNA amplification, mRNA levels, or protein expression with respect to resistance to antimonials. The gene status of each clinical isolate was assessed via qPCR and qRT-PCR. We then compared the molecular pattern against the phenotype determined via an in vitro sensitivity test of the clinical isolates against meglumine antimoniate, which is considered the reference technique. Our results demonstrate significant DNA amplification and/or RNA overexpression in 56% of the clinical isolates with the resistant phenotype. All clinical isolates that exhibited significant overexpression of at least 2 genes displayed a resistant phenotype. Among the 14 genes investigated, 10 genes displayed either significant amplification or overexpression in at least 1 clinical isolate; these genes are involved in several metabolic pathways. Moreover, various gene associations were observed depending on the clinical isolates, supporting the multifactorial nature of Leishmania resistance. Molecular resistance features were found in the 3 Leishmania species investigated (Leishmania infantum, Leishmania major, and Leishmania killicki). To our knowledge, this is the first report of the involvement of molecular resistance genes in field isolates of Leishmania major and Leishmania killicki with the resistance phenotype.

Multilocus microsatellite typing ofLeishmaniaand clinical applications: a review

“…Drug resistance has become a major issue to control leishmaniases in some countries. The mechanisms by which drug resistance emerges and spreads are not completely known [ 30 , 64 ]. MLMT has been used to study strains from patients with treatment failure in order to analyze whether a specific genotype is associated with treatment failure.…”

Species-Specific Antimonial Sensitivity in Leishmania Is Driven by Post-Transcriptional Regulation of AQP1

“…It is interesting to note that when some L . infantum clinical isolates from the Middle East showed CL phenotype, they produced 3–4 fold more AQP1 mRNA [ 42 ]. Therefore, the results of our study can be utilized for a larger study with clinical isolates and strains, but outside the scope of the work presented here.…”

Profils épidémiologique, clinique et biologique de la leishmaniose viscérale infantile à l’hôpital de Kairouan (Tunisie) : à propos de 240 cas

“…Elles présentent également l'avantage d'estimer la charge parasitaire sanguine chez les patients infectés mettant à disposition du clinicien un critère objectif de suivi de la réponse au traitement et donc de la guérison [5]. Il est à signaler que les résistances et les récidives ne sont pas exceptionnelles sous antimoniate de méglumine qui reste le médicament de première intention en Tunisie [5,22]. L'identification iso-enzymatique des parasites en cause présente un intérêt principalement épidémiologique.…”