Leishmania infantum isolates exhibit high infectivity and reduced susceptibility to amphotericin B

Abstract

<p> <italic>L. infantum</italic> isolates from an outbreak of canine leishmaniasis were obtained. Drug sensitivity assays and infectivity studies show significant differences with reference strains.</p>

Preclinical Studies in Anti-Trypanosomatidae Drug Development

“…The in-house chemical collection was tested against L. infantum , L. amazonensis and T. brucei , and outcomes compared with the previously reported anti- T. cruzi activities [ 13 , 14 , 15 , 16 ]: Data summarizing the in vitro and in vivo activity against T. cruzi , toxicology profiles, and potential mechanism of action of the four best hits arising from the previous studies are shown in Table 1 . For the PBox library [ 17 ], we tested the growth inhibitory properties of the collection against a reference strain of L. infantum and an isolate obtained from the latest canine Leishmaniasis outbreak in the World [ 18 , 19 ]. We also collate information about commercial availability, literature reference citations, and other associated biological activity arising from promising hits following extensive literature reviews and database searches (PubChem, Scifinder ® , Reaxys ® , patents, etc).…”

“…Once established, parasites in the exponential phase were transferred and cultured at 28 °C in an axenic medium consisting of BHI-Tryptose supplemented with FBS (10% ( v/v )), hemin (2 × 10 −5 mg/mL), glucose (0.03% ( w/v )), streptomycin (2.0 × 10 −4 g/mL), ampicillin (1.3 × 10 −4 g/mL). Leishmania metacyclic parasites were harvested from promastigote cultures as described previously [ 18 ]. These were used to infect differentiated human acute monocytic leukemia (THP-1) cells at a ratio of 20 parasites per mammalian cell.…”

“…The THP-1 (ATCC ® TIB-202) human acute monocytic leukemia line was grown at 37 °C under a 5% ( v/v ) CO 2 atmosphere in RPMI-1640 medium containing 2-mercaptoethanol (50 μM) and HI-FBS (10% ( v/v )). Differentiation of THP-1 to produce macrophage-like cells was carried out using phorbol 12-myristate-13-acetate (Sigma-Aldrich, Deisenhofen, Germany) [ 18 ].…”

“…Infectivity was assessed by determining the number of infected cells and the number of parasites per infected cell. Infectivity index calculation = (% of infected cells × (amastigotes per cell))/number of total counted cells [ 18 ].…”

Antiprotozoal Compounds from Urolepis hecatantha (Asteraceae)

“…Leishmania infantum (MHOM/BR/2002/LPC-RPV) was obtained from Fiocruz (Collection of Oswaldo Cruz Foundation, Rio de Janeiro, Brazil). Promastigotes were cultured as described [ 16 ] with some modifications at 28°C in an axenic medium (BHI-Tryptose supplemented with: FBS 10%, hemine 2 × 10 −5 mg/mL, glucose 3.0 × 10 −4 g/mL, streptomycin 2.0 × 10 −4 g/mL, ampicillin 1.3 × 10 −4 g/mL) as a low-cost alternative for Leishmania spp. culture.…”