Estudio comparativo de medición entre lecturas visuales y espectrofotométricas en pruebas de susceptibilidad in vitrode aislamientos de candida

Se realizó un estudio de susceptibilidad in vitrofrente a itraconazol, ketoconazol y clotrimazol de 144 cepas de Candida, conservadas y previamente identificadas, aisladas de la cavidad oral de pacientes infectados por elvirus de inmunodeficiencia humana (VIH) con cuadros clínicos de candidiasis orofaríngea (COF). El estudio se llevó a cabo mediante dos metodologías; la primera, utilizando los requerimientos del Clinical and Laboratory Standard Institute (CLSI), en el cual está establecida la lectura visual para determinar los patrones de susceptibilidad; y la segunda, mediante la propuesta de la European Committee on Antibiotic Susceptibility Testing, el cual tiene fijado la lectura espectrofotométrica para eliminar las posibles subjetividades de la metodología del CLSI. Los resultados obtenidos mediante ambas lecturas no mostraron diferencias mayores a dos diluciones en los valores de concentración mínima inhibitoria, y demostraron que ambos métodos se correlacionan y es importante para aquellos laboratorios de pocos recursos económicos.Palabras clave: Susceptibilidad in vitr,; Candida, lectura visual, CLSI, lectura espectrofotométrica, EUCAST azoles, VIH/sida.</p

Sensibilidad in vitro de cepas cubanas de Aspergillus spp. de origen clínico y ambiental

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.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

Microsatellite typing and susceptibilities of serial Cryptococcus neoformans isolates from Cuban patients with recurrent cryptococcal meningitis

Contains fulltext : 124337.pdf (publisher's version ) (Open Access)BACKGROUND: Cryptococcus neoformans is commonly associated with meningoencephalitis in immunocompromised patients and occasionally in apparently healthy individuals. Recurrence of infection after initial treatment is not uncommon. We studied C. neoformans isolates from 7 Cuban patients with recurrent cryptococcal meningitis. Antifungal susceptibility and genotyping with microsatellite molecular typing were carried out. METHODS: Isolates (n = 19) were recovered from cerebrospinal fluid, blood, urine and semen. Antifungal susceptibilities for amphotericin B, fluconazole, flucytosine, itraconazole, voriconazole, posaconazole and isavuconazole were tested by CLSI M27A3 broth microdilution method. Genotyping was done using a panel of 9 microsatellite (STR) markers: (CT)n, (TG)n, (TA)n, (CTA)n, (TCT)n, (CCA)n, (TTAT)n, (ATCC)n and (TATT)n. RESULTS: The average number of isolates/patient was 2.71. The mean time interval between the collection of any two isolates was 52.5 days. All strains were identified as C. neoformans var. grubii (serotype Aalpha). Although none of the strains were resistant to the studied drugs, in serial isolates from two patients, MICs values of triazoles increased 4-5 log2 dilutions over time. STR patterns showed 14 distinctive profiles. In three patients the recurrent infection was associated with genotypically identical isolates. The four other patients had relapse isolates which were genotypically different from the initial infecting strain. CONCLUSION: Recurrences of cryptococcal meningitis in our series of patients was not associated with development of drug resistance of the original strain but by an initial infection with different strains or a reinfection with a new strain

Estudio comparativo de medición entre lecturas visuales y espectrofotométricas en pruebas de susceptibilidad in vitro de aislamientos de candida Comparative study of measure visual and spectrophotometer lectures in a in vitro antifungal susceptibility testing in candida isolates

Se realizó un estudio de susceptibilidad in vitro frente a itraconazol, ketoconazol y clotrimazol de 144 cepas de Candida, conservadas y previamente identificadas, aisladas de la cavidad oral de pacientes infectados por el virus de inmunodeficiencia humana (VIH) con cuadros clínicos de candidiasis orofaríngea (COF). El estudio se llevó a cabo mediante dos metodologías; la primera, utilizando los requerimientos del Clinical and Laboratory Standard Institute (CLSI), en el cual está establecida la lectura visual para determinar los patrones de susceptibilidad; y la segunda, mediante la propuesta de la European Committee on Antibiotic Susceptibility Testing, el cual tiene fijado la lectura espectrofotométrica para eliminar las posibles subjetividades de la metodología del CLSI. Los resultados obtenidos mediante ambas lecturas no mostraron diferencias mayores a dos diluciones en los valores de concentración mínima inhibitoria, y demostraron que ambos métodos se correlacionan y es importante para aquellos laboratorios de pocos recursos económicos.<br>A study of in vitro susceptibility was realized opposite to itraconazol, ketoconazol and clotrimazol of 144 strains of Candida, conserved and previously identified, isolated of the oral cavity of patients infected by the virus of human immunodeficiency (VIH) with clinical pictures of oropharingeal candidiasis (COF). The study was realized by means of two methodologies; the first one, using the requests of the Clinical and Laboratory Standard Institute (CLSI), in which the visual reading is established to determine the patterns of susceptibility; and the second one, by means of the proposal of the European Committee on Antibiotic Susceptibility Testing, which has fixed the spectrophotometric to eliminate the possible subjectivities of the methodology of the CLSI. The results obtained by means of both readings did not show differences bigger than two dilutions in the values of minimal inhibitory concentration, demonstrating that both methods are correlated and it is important for those laboratories of few economic resources

In vitro susceptibility of Cuban Aspergillus spp. strains of clinical and environmental origin

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