Phenotypic and genotypic characterization of Colombian clinical isolates of Sporothrix spp

Introduction. For over a century, Sporothrix schenckii was considered the sole species responsible for sporotrichosis. In 2007, scientific community confirmed the disease could be caused by various Sporothrix species. These species differed in their virulence factors and their antifungal sensitivity. Objective. This study aims to characterize 42 Colombian clinical isolates of Sporothrix spp. phenotypically and genotypically. Material and methods. Forty-two clinical isolates were characterized using phenotypic methods. It involved various culture media to determine their growth range at different temperatures and to assess the type and distribution of pigment and colony texture. Microscopic morphology was evaluated through microcultures, as well as the conidia diameter, type of sporulation, and morphology. Additionally, the assimilation of carbohydrates was selected as a physiological trait for species identification. Genotyping of 40 isolates was performed through partial amplification of the calmodulin gene, followed by sequence analysis. Results. Molecular studies enabled the identification of 32 isolates of S. schenckii and 8 isolates of S. globosa. The combination of phenotypic and genotypic methods eased these species characterizations and the recognition keys development based on parameters such as growth diameter at 25 and 30 °C, colony texture (membranous or velvety) on potato dextrose agar, and microscopic morphology with predominance of pigmented triangular, elongated oval globose, or subglobose conidia. Conclusions. Confirmation of the phenotypic characteristics and molecular analysis is crucial for identifying Sporothrix species and determining adequate treatment. This study represents the first phenotypical and genotypical characterization of clinical isolates of Sporothrix spp. reported in Colombia.

Introducción. Por más de un siglo se creyó que Sporothrix schenckii era la única especie responsable de la esporotricosis. Sin embargo, en el 2007, se consideró que podría ser causada por diferentes especies de Sporothrix, que difieren en sus factores de virulencia y su sensibilidad a los antifúngicos. Objetivo. Caracterizar fenotípica y genotípicamente 42 aislamientos clínicos colombianos de Sporothrix spp. Materiales y métodos. Se caracterizaron 42 aislamientos clínicos mediante métodos fenotípicos. Se usaron varios medios de cultivo para determinar el rango de crecimiento a diferentes temperaturas, el tipo y la distribución del pigmento, y la textura de las colonias. Se evaluó la morfología microscópica por microcultivos mediante la determinación del diámetro, el tipo de esporulación y la morfología de las conidias. La asimilación de carbohidratos se usó como una característica fisiológica para identificar las especies. La genotipificación de los 40 aislamientos se llevó a cabo mediante la amplificación parcial del gen que codifica para la calmodulina y se confirmó por secuenciación. Resultados. Mediante estudios moleculares, se identificaron 32 aislamientos de S. schenckii y ocho de S. globosa. La combinación de métodos fenotípicos y genotípicos permitió caracterizar las especies y construir claves para su reconocimiento, con base en parámetros como el diámetro de crecimiento a 25 y 30 °C, la textura de las colonias (membranosa, aterciopelada) en agar papa dextrosa y la morfología microscópica con predominio de conidias (triangulares pigmentadas, ovales globosas elongadas, subglobosas). Conclusiones. La caracterización fenotípica y los análisis moleculares son necesarios para identificar las especies de Sporothrix y, de esta forma, elegir el tratamiento indicado. Esta es la primera caracterización fenotípica y genotípica reportada de aislamientos clínicos colombianos de Sporothrix spp.

The conventional diagnosis challenge: Real-time PCR and nested PCR correlation with the scoring system for individuals at high-risk of Pneumocystis jirovecii pneumonia

Introduction. Pneumocystis jirovecii is an opportunistic fungus that affects mainly people living with HIV (CD4 cell count lower than 200 cells/ml) and other immunosuppressed patients. Since P. jirovecii does not grow on routine mycological media, diagnosis of P. jirovecii pneumonia relies on indirect evidence of its presence in respiratory samples. Objectives. To associate the results of direct immunofluorescence and two molecular methods with a score to predict P. jirovecii pneumonia in patients with AIDS. Materials and methods. A prospective study was conducted with 40 patients. A respiratory sample collected before treatment was subjected to direct immunofluorescence using the Merifluor kit, to nested PCR targeting the mitochondrial large subunit ribosomal RNA, and to the VIASURE real-time PCR kit. Results. These three techniques revealed P. jirovecii in 6, 12, and 15 samples, respectively. All positive samples by direct immunofluorescence were positive by nested PCR, and all positive samples by nested PCR amplified by real-time PCR. There was a statistically significant association between the P. jirovecii pneumonia score and the molecular methods. Two patients were early diagnosed and responded well to treatment. Conclusion. Molecular methods, especially real-time PCR, are recommended for early diagnosis of P. jirovecii pneumonia in AIDS patients.

Introducción. Pneumocystis jirovecii es un hongo oportunista que afecta principalmente a personas con HIV (recuento de CD4 menor de 200 células/ml) y a otros pacientes inmunosuprimidos. Como P. jirovecii no crece en los medios micológicos de rutina, el diagnóstico de neumonía por P. jirovecii se basa en la evidencia presente en muestras respiratorias. Objetivos. Asociar los resultados de la inmunofluorescencia directa y los de dos métodos moleculares con un puntaje para predecir la neumonía causada por P. jirovecii en pacientes con sida. Materiales y métodos. Se realizó un estudio prospectivo de 40 pacientes. Se recolectó una muestra respiratoria antes del inicio de tratamiento y se sometió a una prueba de inmunofluorescencia directa con el kit Merifluor, una PCR anidada para la amplificación de la subunidad larga del ribosoma mitocondrial y una PCR en tiempo real usando el kit VIASURE. Resultados. Estas tres técnicas evidenciaron la presencia de P. jirovecii en 6, 12 y 15 muestras, respectivamente. Todas las muestras positivas por inmunofluorescencia directa fueron positivas en la PCR anidada y todas las muestras positivas en la PCR anidada amplificaron por PCR en tiempo real. Se encontró una asociación estadística entre los valores de la neumonía causada por P. jirovecii y los métodos moleculares. Dos pacientes con diagnóstico temprano respondieron satisfactoriamente al tratamiento. Conclusión. Se recomiendan los métodos moleculares, especialmente la PCR en tiempo real, para el diagnóstico temprano de neumonía causada por P. jirovecii en pacientes con sida.

GATA2 variants in patients with non-tuberculous mycobacterial or fungal infections without known immunodeficiencies

ABSTRACT Introduction Haploinsufficiency of the hematopoietic transcription factor GATA2 is associated with a broad spectrum of diseases, including infection susceptibility and neoplasms. We aimed to investigate GATA2 variants in patients with non-tuberculous mycobacterial (NTM) and/or fungal infections (FI) without known immunodeficiencies. Method We performed GATA2 genotyping in patients with NTM and/or FI. Results Twenty-two patients were enrolled (seventeen FI, four NTM and one with both infections). The pathogenic variant NG_029334.1:g.16287C>T was found in one patient (4.5%) and two asymptomatic offsprings. We also found the likely-benign variant NG_029334.1:g.12080G>A (rs2335052), the benign variant NG_029334.1:g.16225C>T (rs11708606) and the variant of uncertain significance NG_029334.1:g.16201G>A (rs369850507) in 18.2%, 27.3%, and 4.5% of the cases, respectively. Malignant diseases were additionally diagnosed in six patients. Conclusion Although detected in 45.4% of the patients, most GATA2 variants were benign or likely benign. Identifying a pathogenic variant was essential for driving both the patient's treatment and familial counseling. Pathogenic variants carriers should receive genetic counseling, subsequent infection prevention measures and malignancies surveillance. Additionally, case-control genotyping should be carried out in Brazil to investigate whether the observed variants may be associated with susceptibility to opportunistic infections and/or concurrent neoplasms.

Chronic disseminated histoplasmosis with lesions restricted to the mouth: case report

Reportamos um caso raro de histoplasmose crônica disseminada com diversas lesões ulceradas na cavidade oral de um paciente alcoólatra, sem o vírus da imunodeficiência humana, com nenhum outro sinal detectável ou sintomas de doença sistêmica ou manifestações extra-orais. Análise histopatológica revelou processo inflamatório crônico com granulomas contendo organismos fúngicos. O isolamento do Histoplasma capsulatum forneceu o diagnóstico definitivo. Tratamento com itraconazol resultou numa remissão completa das lesões orais. De acordo com nosso conhecimento, este é o segundo caso reportado de histoplasmose oral em um paciente HIV negativo descrito no Brasil.