All clinical manifestations of leishmaniasis exist in Colombia, the cutaneous form being the most frequent in the department of Sucre, where the Leishmania species associated with cutaneous leishmaniasis (CL) is unknown. This study was carried out to determine which Leishmania species was responsible for CL in Sucre, based on amplification and sequencing of the Cyt b gene. Isolates of Leishmania were obtained after CL diagnosis of eight patients who received attention in several health care centers of the study area. The nucleotide sequences obtained from patients were compared to Leishmania reference strains and six of the isolates identified as Leishmania (Viannia) braziliensis, the remaining two being identified as Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis. This represents the first report of the presence of L. (V.) guyanensis on the Caribbean coast of Colombia.

Several important antifungal drugs inhibit the synthesis of ergosterol, a lipid that modulates the thickness, fluidity and permeability of fungal cell membranes. These include the azole antifungals, which block ergosterol biosynthesis by inhibiting lanosterol demethylase (Erg11p). The resulting depletion of cellular ergosterol and the accumulation of 'toxic' sterol intermediates are both thought to cause plasma membrane dysfunction and ultimately growth arrest. However, the effects of ergosterol depletion upon the function of intracellular membranes and organelles are not well described. The purpose of this study was to characterize the effects of azole treatment upon the integrity of the Candida albicans vacuole, and determine if, in turn, vacuolar trafficking influences azole susceptibility. vii TABLE OF CONTENTS CHAPTER 1.