Sensibilidad in vitro de cepas cubanas de Aspergillus spp. de origen clínico y ambiental / In vitro susceptibility of Cuban Aspergillus spp. strains of clinical and environmental origin

Introducción. En Cuba se desconoce el comportamiento de la sensibilidad de Aspergillus spp. a los antifúngicos recomendados para el tratamiento de la aspergilosis: la anfotericina B, el itraconazol, el voriconazol y las equinocandinas. La influencia del ambiente puede condicionar la aparición de resistencia en estos microorganismos. Objetivo. Evaluar la sensibilidad in vitro de cepas de Aspergillus spp. a la anfotericina B, el itraconazol y el voriconazol, y la relación de los patrones de sensibilidad con su origen. Materiales y métodos. Se determinaron las concentraciones inhibitorias mínimas de la anfotericina B, el itraconazol y el voriconazol para 60 cepas de Aspergillus spp. de origen clínico y ambiental mediante el método M38-A2 del Clinical and Laboratory Standard Institute. Resultados. Se encontraron 21 cepas resistentes a la anfotericina B (principalmente en muestras clínicas y ambientes hospitalarios) y tres cepas resistentes al itraconazol (en ambientes interiores y exteriores no hospitalarios). No se hallaron cepas resistentes al voriconazol. No se encontró relación entre el origen de las cepas y su sensibilidad. Conclusiones. Se sugiere la posible existencia de factores ambientales o interacciones con genotipos resistentes que pueden dar origen a fenotipos resistentes en Cuba. Este es el primer reporte del país de cepas de Aspergillus spp. resistentes in vitro. Los resultados ameritan ampliar el estudio para incluir análisis moleculares y filogenéticos.

Introduction: The behavior of antifungal susceptibility of Aspergillus spp. in Cuba remains unknown. The antifungals recommended to treat aspergillosis are amphotericin B, itraconazole, voriconazole and echinocandins. The influence of the environment may set off the emergence of drug-resistance in these microorganisms. Objective: To evaluate in vitro susceptibility of Aspergillus spp. strains to amphotericin B, itraconazole and voriconazol, and the relationship between susceptibility patterns and their origin. Materials and methods: Minimum inhibitory concentrations of amphotericin B, itraconazole and voriconazole were determined for 60 Aspergillus spp. strains of clinical and environmental origin using the M38-A2 method of the Clinical and Laboratory Standards Institute. Results: We found 21 amphotericin B resistant strains (mainly from clinical samples and hospital environments), as well as three itraconazole resistant strains (from non-hospital outdoor and indoor environments). No voriconazole resistance was found. No relationship was found between strain origin and susceptibility. Conclusions: Results suggest the possible existence of environmental factors or interactions with resistant genotypes which may give rise to resistant phenotypes in our country. This is the first report of in vitro Aspergillus spp. resistant strains in Cuba. These studies should be broadened and include molecular and phylogenetic analyses.

Enzyme-linked immunosorbent assay for detection and quantification of Cryptococcus neoformans antigen

An enzyme-linked immunosorbent assay was standardized for the detection of cryptococcal antigen in serum and cerebrospinal fluid. The system was evaluated in clinical samples from patients infected by human immunodeficiency virus with and without previous cryptococcosis diagnosis. The evaluated system is highly sensitive and specific, and when it was compared with latex agglutination there were not significant differences. A standard curve with purified Cryptococcus neoformans antigen was settled down for the antigen quantification in positive samples