Susceptibility to paromomycin in clinical isolates and reference strains of Leishmania species responsible for tegumentary leishmaniasis in Brazil.

• Clinical isolates were typed as Leishmania (Viannia) braziliensis, L. (Leishmania) amazonensis and L. (V.) guyanensis. • Strains and clinical isolates responsible for tegumentary leishmaniasis presented variation in in vitro susceptibility to paromomycin in both stages of parasite. • Intracellular amastigotes were more susceptible to paromomycin than promastigotes. Treatment of tegumentary leishmaniasis in Brazil is limited to pentavalent antimonial, amphotericin B and pentamidine. These drugs, administered parenterally, cause several side effects and have a varied clinical response, depending on the species of Leishmania. Urgent expansion of the therapeutic arsenal against the disease is therefore necessary. Paromomycin is an aminoglycoside antibiotic that has already been approved for the treatment of visceral leishmaniasis in Southeast Asia. Here, we provide an in vitro evaluation of the activity of paromomycin in fifteen clinical isolates from patients with tegumentary leishmaniasis at a reference center for the treatment of the disease. Furthermore, the in vitro susceptibility to this drug in reference strains of Leishmania species that are endemic in Brazil has also been evaluated. Among the clinical isolates, nine were typed as Leishmania (Viannia) braziliensis , five as L. (Leishmania) amazonensis and one as L. (V.) guyanensis. Although never exposed to paromomycin, we found variable susceptibility among these isolates and reference strains in promastigotes and intracellular amastigotes, with the drug being more active in the amastigote form of the parasite. This study provides a preclinical dataset that is useful for the evaluation of paromomycin in the treatment of tegumentary leishmaniasis caused by species that are endemic in Brazil. Image, graphical abstract [ABSTRACT FROM AUTHOR]