Susceptibility testing of Leishmania spp. against amphotericin B and fluconazole using the Sensititre™ YeastOne™ YO9 platform

Abstract

Background: Current drug regimens for cutaneous leishmaniasis (CL) include toxic systemic therapies such as amphotericin B (AB) and pentavalent antimonials. Fluconazole (FZ) is a well-tolerated potential oral alternative for the management CL. To date, few objective data exist to guide clinical decision-making when selecting a therapeutic agent a priori, and standardized, clinically-approved drug susceptibility testing platforms for Leishmania spp. have yet to be established. The Sensititre™ YeastOne™ YO9 plate is a commercialized drug susceptibility plate including AB and FZ used for routine testing of non-fastidious yeast. Our objective was to adapt the readily available Sensititre™ YeastOne™ YO9 plate, to determine drug susceptibility profiles of AB and FZ in cultured isolates of Old World and New World Leishmania spp. for the treatment of CL. Methods: Promastigotes were cultured in Tobie's medium with Locke's overlay until log phase growth was achieved, inoculated into the Sensititre™ system, and incubated over 96 H. minimum inhibitory concentrations (MICs) were determined colorimetrically, and promastigote death was assessed by conventional microscopy out to 96-h. Colour change correlated to MIC values. Results: All strains tested exhibited MIC values for FZ that were ≥ 256 μg/mL. New World strains demonstrated reduced susceptibility to AB (0.25 μg/mL-0.50 μg/mL AB) compared to Old World strains at 0.12 μg/mL AB (p = 0.02). Seventeen (61%) of 28 Viannia isolates versus 82% (27/33) of non-Viannia isolates were resistant at 0.12 μg/mL AB (p = 0.09). For L. V. braziliensis isolates, mean MIC for AB was 0.375 ± 0.14 μg/mL (range 0.25-0.50 μg/mL), while for isolates of L. V. panamensis it was 0.314 ± 0.26 μg/mL (range 0.12-1.0 μg/mL). Conclusions: We adapted the Sensititre™ YeastOne™ YO9 plate for testing of Leishmania spp. susceptibility profiles for commonly used antifungals in the treatment of CL, including AB and FZ. Given its current utility in mycology, optimization of the system for potential clinical implementation in parasitology should be pursued. However evaluation of clinically relevant amastigote-stage stages, and higher concentrations of FZ beyond the upper limit concentration of the Sensititre™ YeastOne™ Y09 plate would be required.

Lipid Systems for the Delivery of Amphotericin B in Antifungal Therapy

“…AmB is effective in the treatment of aspergillosis [26], candidiasis [27], blastomycosis [28], paracoccidioidomycosis [29], coccidioidomycosis [28], cryptococcosis [30], histoplasmosis [28], mucormycosis [31], some hyalohyphomycosis [32] and phaeohyphomycosis [33], dermatophytosis [34] and other dermatomycosis [35], sporotrichosis [36], talaromycosis (formerly penicilliosis) [37], and trichosporonosis [38]. The drug is also active against some parasitic diseases, namely leishmaniasis (cutaneous, mucocutaneous, and visceral) [22,39] and primary amebic meningoencephalitis [22,40].…”

“…However, the high molecular weight of the drug (M r 924.08) and its reduced solubility and permeability contribute to its poor pharmacokinetic profile [25,41,42]. AmB is also unstable in acid media, sensitive to light and temperature [25,42], requiring storage between 2-8 • C. some parasitic diseases, namely leishmaniasis (cutaneous, mucocutaneous, and visceral) [22,39] and primary amebic meningoencephalitis [22,40].…”

An overview of the treatment of cutaneous leishmaniasis

“…Amphotericin B (AmB) is a macrolide polyene antibiotic with potent antifungal and anti-leishmanial activity that targets ergosterol, the principal membrane component of Leishmania spp. 37 , 38 . It is considered a second-line treatment for CL.…”

“…It is considered a second-line treatment for CL. There are four formulations of AmB: one is amphotericin B deoxycholate, and the rest are lipid formulations of the drug, liposomal amphotericin, cholesterol dispersion amphotericin, and lipid complex amphotericin 2 , 8 , 37 . The three lipid formulations were made to minimize adverse events such as nephrotoxicity reported with amphotericin B deoxycholate; however, the only drug of this type approved by the US Food and Drug Administration (FDA) is liposomal amphotericin B (L-AmB) 8 .…”

Effectiveness of Core-Shell Nanofibers Incorporating Amphotericin B by Solution Blow Spinning Against Leishmania and Candida Species

“…For granulomatous and invasive forms of candidosis, AmpB and other antifungals such triazoles, allylamines (terbinafine), and echinocandins (caspofungin), are elective drugs with good clinical outcomes (López-Martínez, 2010). However, unwanted characteristics of AmpB, including high cost, toxicity, and necessity of parenteral administration, may limit its use (Mattos et al, 2015;Turner et al, 2015;Kariyawasam et al, 2019). For this reason, other vehicles have been developed with the aim of developing new strategies for the administration of this drug, such as films, nanofibers, nanoformulations, as well as systems focused on delivery to the oral mucosa (Hodiamont et al, 2015;Sarwar et al, 2018;Souza et al, 2018;Edmans et al, 2020).…”