Comparación del examen directo, el cultivo y el blanco de calcoflúor para el diagnóstico de onicomicosis / Comparison of direct microscopy, culture and calcofluor white for the diagnosis of onychomycosis

Antecedentes. El diagnóstico micológico de onicomicosis puede establecerse mediante el examen microscópico directo (KOH) de una muestra clínica, el cultivo y la adición de blanco de calcoflúor. Objetivos. Comparar el porcentaje de positividad y el grado de correlación entre la adición de KOH, el cultivo y la tinción con blanco de calcoflúor en el diagnóstico de onicomicosis. Métodos. Estudio descriptivo, transversal y comparativo. Se utilizaron muestras de fragmentos ungueales de los pies para la adición de KOH, cultivo y adición de blanco de calcoflúor para examen bajo fluorescencia. Se calculó el porcentaje de positividad de las diferentes técnicas y se determinó el grado de correlación entre ellas (Programa Epi Info v 3.4.3©). Resultados. La adición de KOH dio un resultado positivo en el 66,67% de los casos, el cultivo en el 33,33% y la tinción con blanco de calcoflúor en el 57,58%. El KOH y el blanco de calcoflúor se asociaron a un mayor porcentaje de positividad que el cultivo (p < 0,01 y p < 0,05, respectivamente). El grado de correlación entre el KOH y el blanco de calcoflúor fue excelente (κ = 0,8085; p < 0,0001), mientras que fue débil entre el KOH y el cultivo y entre el blanco de calcoflúor y el cultivo. Conclusiones. No se recomienda el uso sistemático de blanco de calcoflúor en los laboratorios porque no parece conferir beneficios adicionales cuando se compara con el KOH. Esto reviste especial importancia cuando los recursos son limitados(AU)

Background. Mycological diagnosis of onychomycosis can be performed by direct microcopy (KOH), cultures and calcofluor white. Aims. To compare the percentage of positivity and the degree of correlation of KOH, cultures and calcofluor white for the diagnosis of onychomycosis. Methods. Descriptive, transversal and comparative study. Samples of toenails with onychomycosis were used for KOH, cultures and calcofluor white under fluorescence. The percentage of positivity of the different techniques was calculated and the degree of correlation between them was determined (Epi Info v 3.4.3©). Results. KOH was positive in 66.67% of the cases, cultures in 33.33% and calcofluor white in 57.58%. KOH and calcofluor white had a higher percentage of positivity than culture (p<0.01 and p<0.05 respectively). The degree of correlation between KOH and calcofluor white was excellent (κ=0.8085; p<0.0001); however, the degree of correlation between KOH and culture and between calcofluor white and culture was poor. Conclusions. The use of calcofluor white is not recommended in routine laboratories because it does not seem to bring any additional benefits when comparing with KOH. This is especially important when funding is a great problem(AU)

Comparison of direct microscopy, culture and calcofluor white for the diagnosis of onychomycosis.

BACKGROUND: Mycological diagnosis of onychomycosis can be performed by direct microcopy (KOH), cultures and calcofluor white. AIMS: To compare the percentage of positivity and the degree of correlation of KOH, cultures and calcofluor white for the diagnosis of onychomycosis. METHODS: Descriptive, transversal and comparative study. Samples of toenails with onychomycosis were used for KOH, cultures and calcofluor white under fluorescence. The percentage of positivity of the different techniques was calculated and the degree of correlation between them was determined (Epi Info v 3.4.3(©)). RESULTS: KOH was positive in 66.67% of the cases, cultures in 33.33% and calcofluor white in 57.58%. KOH and calcofluor white had a higher percentage of positivity than culture (p<0.01 and p<0.05 respectively). The degree of correlation between KOH and calcofluor white was excellent (κ=0.8085; p<0.0001); however, the degree of correlation between KOH and culture and between calcofluor white and culture was poor. CONCLUSIONS: The use of calcofluor white is not recommended in routine laboratories because it does not seem to bring any additional benefits when comparing with KOH. This is especially important when funding is a great problem.

Aeromycological study at the intensive care unit of the "Dr. Manuel Gea Gonzalez" General Hospital

INTRODUCTION: An aeromycological study verifies the presence and quantifies the concentration of fungal propagules in the air. It is very important in the hospital setting because of the increasing numbers of immunosuppressed and severely ill patients. The objective of this study was to determine the concentration of fungi in the air of the intensive care unit (ICU) of "Dr. Manuel Gea González" General Hospital. METHODS: This is a descriptive, observational cross-sectional study. Air samples were obtained with a single stage Thermo-Andersen Viable Particle Sampler (Thermo Electron Corporation -Massachusetts, U.S.A.) in a Petri dish with potato dextrose agar for 15 minutes at two different times (morning and afternoon) and heights (1 and 1.5 meters). The Petri dishes were incubated for five to seven days at 27ºC, the number of colonies was counted, and the total CFU/m³ was determined. The isolated fungal genera were identified by morphological features. Epi Info v. 3.4.3 © was used for statistical analysis. RESULTS: The mean concentration of fungi in the air of the ICU was 85.08 ± 29.19 CFU/m³; while in the outside air it was 84.3 ± 17.23 CFU/m³ (p = 0.96). The fungi isolated were: Cladosporium spp., Penicillium spp., Aspergillus spp. (non-fumigatus), Fusarium spp., Exophiala spp., Syncephalastrum spp., and Acremonium spp. DISCUSSION: Fungal spores were found in the air of the ICU and Cladosporium spp. was the most frequently isolated fungi. There was no difference according to sampling time or height.

Aeromycological study at the intensive care unit of the "Dr. Manuel Gea Gonzalez" General Hospital.

INTRODUCTION: An aeromycological study verifies the presence and quantifies the concentration of fungal propagules in the air. It is very important in the hospital setting because of the increasing numbers of immunosuppressed and severely ill patients. The objective of this study was to determine the concentration of fungi in the air of the intensive care unit (ICU) of "Dr. Manuel Gea González" General Hospital. METHODS: This is a descriptive, observational cross-sectional study. Air samples were obtained with a single stage Thermo-Andersen Viable Particle Sampler (Thermo Electron Corporation - Massachusetts, U.S.A.) in a Petri dish with potato dextrose agar for 15 minutes at two different times (morning and afternoon) and heights (1 and 1.5 meters). The Petri dishes were incubated for five to seven days at 27° C, the number of colonies was counted, and the total CFU/m(3) was determined. The isolated fungal genera were identified by morphological features. Epi Info v. 3.4.3 © was used for statistical analysis. RESULTS: The mean concentration of fungi in the air of the ICU was 85.08 ± 29.19 CFU/m(3); while in the outside air it was 84.3 ± 17.23 CFU/m(3) (p = 0.96). The fungi isolated were: Cladosporium spp., Penicillium spp., Aspergillus spp. (non-fumigatus), Fusarium spp., Exophiala spp., Syncephalastrum spp., and Acremonium spp. DISCUSSION: Fungal spores were found in the air of the ICU and Cladosporium spp. was the most frequently isolated fungi. There was no difference according to sampling time or height.