Visceral leishmaniasis unresponsive to pentostam caused by Leishmania tropica in Kenya.

We report the characterization of 6 Leishmania tropica isolates from 2 patients with visceral leishmaniasis who were unresponsive to treatment with sodium stibogluconate. The Leishmania isolates, MHOM/KE/81/NLB-029A, -029XIB, and -029XIC and MHOM/KE/81/NLB-030I, -030B, and -030XXA, all from splenic aspirates, were characterized by cellulose acetate electrophoresis using 11 enzymes: malate dehydrogenase, malic enzyme, phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, superoxide dismutase, glutamate-oxaloacetate transaminase, adenylate kinase, nucleoside hydrolase, mannose phosphate isomerase, glucose phosphate isomerase, and phosphoglucomutase. Isozyme migration patterns were indistinguishable from those of 2 WHO reference strains of Leishmania tropica (MHOM/SU/60/LRC-L39, NLB-305 and MHOM/IQ/OO/LRC-L36, NLB-067). These are the first reported cases of visceral leishmaniasis (kala-azar) caused by L. tropica in Africa; these cases were refractory to sodium stibogluconate.