Maria Del Pilar Jiménez-Alzate

Introducción: La histoplasmosis es una micosis endémica en Colombia, pero los datos sobre sus características clínicas en la era reciente son limitados, particularmente en lo que respecta a las diferencias entre personas que viven con el VIH (PVV) y aquellas que no. Este estudio tuvo como objetivo describir y comparar las características de pacientes hospitalizados con histoplasmosis según su estado serológico para el VIH. Materiales y métodos: Se realizó un estudio de cohorte retrospectivo en un hospital universitario de Medellín, Colombia. Se incluyeron todos los pacientes adultos (>18 años) hospitalizados entre el 1 de enero de 2014 y el 31 de diciembre de 2021, con un diagnóstico confirmado de histoplasmosis mediante cultivo, histopatología, biología molecular o detección de antígeno urinario. Se extrajeron y analizaron datos demográficos, clínicos, de laboratorio y de desenlaces. Resultados: Se identificaron 51 pacientes con histoplasmosis confirmada. La mediana de edad fue de 38 años (RIC 29-46) y el 86,3% (n=44) eran hombres. El 80,4% (n=41) de los pacientes eran PVV, de los cuales el 97,6% (40/41) tenía un recuento de linfocitos T CD4+ <200 células/uL. Ningún paciente con VIH estaba recibiendo terapia antirretroviral activa al momento del diagnóstico. La forma diseminada progresiva fue significativamente más frecuente en PVV (92,7% vs. 60,0%; p=0,021). La coinfección con tuberculosis se documentó en el 25,5% (13/51) de la cohorte. La mortalidad hospitalaria global fue del 9,8% (5/51), numéricamente mayor en el grupo VIH-negativo (20,0% vs. 7,3%; p=0,250). Discusión: En este centro de referencia, la histoplasmosis en pacientes hospitalizados afectó predominantemente a hombres con infección por VIH avanzada y no tratada. La alta frecuencia de coinfección con tuberculosis subraya un desafío diagnóstico crítico. La mortalidad observada fue inferior a la reportada en otras series regionales, lo que podría estar asociado al manejo en un centro especializado, aunque este hallazgo requiere validación en estudios prospectivos y multicéntricos.

The genomics of human pathogenic thermally dimorphic fungi has advanced significantly thanks to international initiatives such as the 1000 Fungal Genomes Project, which has reported a wide range of complete genomes in public repositories. This has driven the genomic characterization of genera such as Histoplasma, Paracoccidioides, and Sporothrix, including clinically relevant Colombian isolates. Genomic studies have revealed key aspects of their diversity, evolution, and host adaptation, while enabling comparative analyses based on orthologous genes that highlight both conservation and divergence among lineages. Beyond their description, the availability of complete genomes has had direct applications in diagnostics through systematic comparison algorithms that identify unique genomic regions serving as highly specific molecular targets. This has facilitated the design and validation of innovative PCR assays for the above-mentioned genera, overcoming the limitations of traditional candidate-gene approaches. In Colombia, significant challenges remain, including the limited availability of clinical isolates, biosafety requirements, and difficulties in timely diagnosis. In this context, we aimed to analyze the current state of assembled genomes of these dimorphic fungi available in public databases for Colombia and their use in the development of highly specific molecular diagnostic tools.

La paracoccidioidomicosis es una micosis sistémica endémica en Latinoamérica. La presentación más frecuente compromete crónicamente los pulmones, la piel y las mucosas. Al inicio, este paciente presentó, por varios años, una lesión única en la mucosa oral que, en ausencia de otros síntomas, se relacionó con una neoplasia maligna, específicamente con un carcinoma escamocelular.La diferenciación entre los dos diagnósticos se hace mediante un examen directo, un estudio histopatológico y cultivos iniciales y subsecuentes. Sin embargo, tales estudios no fueron concluyentes. Después de varias consultas y pruebas, con los resultados del examen directo, la inmunodifusión y la PCR en tiempo real se confirmó el diagnóstico de paracoccidioidomicosis crónica multifocal.Este caso alerta sobre la ausencia de sospecha clínica de micosis endémicas, dada la presencia de lesiones mucocutáneas que pueden ser producidas por hongos como Paracoccidioides spp, y la importancia de considerarlas entre los diagnósticos diferenciales.

Introducción. Las dermatofitosis son infecciones fúngicas superficiales de epitelios queratinizados. La tinea capitis es una de ellas y afecta a poblaciones escolares vulnerables. Carpinelo es un barrio del área periférica de Medellín con precarias condiciones socioeconómicas. Ante la sospecha de un brote de dermatofitosis, losafectados fueron evaluados.Objetivo. Evaluar clínica y microbiológicamente pacientes del barrio Carpinelo con sospecha de micosis cutáneas para determinar la presencia de un brote por dermatofitos.Materiales y métodos. Se llevó a cabo un estudio descriptivo, de corte longitudinal, con muestreo a conveniencia. Se hizo una búsqueda activa de casos en el Jardín Educativo Buen Comienzo de Carpinelo en niños de la institución y sus familiares. Se evaluaron clínicamente y se tomaron muestras de escamas y cabellos para exámenes directos y cultivos microbiológicos. Se analizó el perfil demográfico, clínico y micológico, con el programa estadístico SPSS™, versión 25.Resultados. Se estudiaron 57 pacientes, 47 eran menores de edad con una media de edad de seis años; se observó una proporción de hombres y mujeres de 2:1. Los pacientes con resultados positivos se diagnosticaron con tinea capitis (78,95 %), tinea faciei (15,79 %) y tinea corporis (10,52 %). El 75,43 % de los pacientes recibió tratamiento previo y de estos el 69,73 % fue con esteroides. El examen directo fue positivo en el 53,84 % y los cultivos en el 46,5 % de los casos. Los agentes aislados fueron: Microsporum canis (77,77 %), Trichophyton spp. (11,11 %), Trichophyton rubrum (5,55 %) y Malassezia spp. (5,55 %).Conclusión. Tinea capitis fue la presentación clínica más común y M. canis el dermatofito más frecuentemente aislado. Llamó la atención el uso de esteroides como primera y única opción del tratamiento empírico‚ lo cual resalta la importancia del diagnóstico microbiológico para proporcionar la terapia apropiada.

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 ºC, 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.

Histoplasma capsulatum is a dimorphic, thermal, and nutritional fungus. In the environment and at an average temperature of 28 °C, it develops as a mold that is composed of infecting particles. Once in the host or in cultures at 37 °C, it undergoes a transition into the parasitic form. In the present work, we performed chemical extraction and characterization using chromatography techniques of the associated lipid composition of the external surface of the cell wall of the mycelial phase of two isolates of the H. capsulatum: one clinical and one environmental. Several differences were evidenced in the fatty acids in the phospholipid composition. Surface pressure–area isotherms and compression module curves of the Amphotericin B and lipid extract monolayers, as well as (AmB)-lipid extract mixed monolayers were recorded. Results show a high affinity of AmB towards lipid extracts. The most stable monolayers were formed by AmB + environmental with a mass ratio of 1:3 and AmB + clinical with a mass ratio of 1:2. Knowledge of the AmB aggregation processes at a molecular level and the characterization of the lipid extracts allows the possibility to understand the interaction between the AmB and the lipid fractions of H. capsulatum.

: Histoplasmosis, one of the most frequent endemic mycoses in the Americas, is caused by the inhalation of airborne conidia of Histoplasma capsulatum. Better understanding of the distribution of this fungus in the environment is important for the development of appropriate public health measures to prevent human infections. Previously, we used Hc100 nested polymerase chain reaction (PCR) to identify H. capsulatum DNA in 10% of environmental samples in Colombia. Here, we validate a 100-kDa real-time PCR assay for the detection of this fungus in the environment. Using this method, we identified H. capsulatum DNA in 80% of samples of raw organic materials, such as chicken manure, soil from caves, and bird and bat guano, as well as in 62% of samples of organic fertilizer that underwent the composting process. We demonstrated that 100-KDa real-time PCR is a useful tool for environmental surveillance that can be used to identify the potential reservoirs of H. capsulatum and to prevent outbreaks, especially in people with the higher risk of exposure, such as spelunkers, farmers, poultry manure collectors, and anyone who handle organic fertilizers or bat and bird excreta.

Coccidioides is a soil-borne fungal pathogen and causative agent of a human respiratory disease (coccidioidomycosis) endemic to semi-desert regions of southwestern United States, Mexico, Central and South America. Aerosolized arthroconidia inhaled by the mammalian host first undergo conversion to large parasitic cells (spherules, 80–100 μm diameter) followed by endosporulation, a process by which the contents of spherules give rise to multiple endospores. The latter are released upon rupture of the maternal spherules and establish new foci of lung infection. A novel feature of spherule maturation prior to endosporulation is the secretion of a lipid-rich, membranous cell surface layer shed in vivo during growth of the parasitic cells and secretion into liquid culture medium during in vitro growth. Chemical analysis of the culture derived spherule outer wall (SOW) fraction showed that it is composed largely of phospholipids and is enriched with saturated fatty acids, including myristic, palmitic, elaidic, oleic, and stearic acid. NMR revealed the presence of monosaccharide- and disaccharide-linked acylglycerols and sphingolipids. The major sphingolipid components are sphingosine and ceramide. Primary neutrophils derived from healthy C57BL/6 and DBA/2 mice incubated with SOW lipids revealed a significant reduction in fungicidal activity against viable Coccidioides arthroconidia compared to incubation of neutrophils with arthroconidia alone. Host cell exposure to SOW lipids had no effect on neutrophil viability. Furthermore, C57BL/6 mice that were challenged subcutaneously with Coccidioides arthroconidia in the presence of the isolated SOW fraction developed disseminated disease, while control mice challenged with arthroconidia alone by the same route showed no dissemination of infection. We hypothesize that SOW lipids contribute to suppression of inflammatory response to Coccidioides infection. Studies are underway to characterize the immunosuppressive mechanism(s) of SOW lipids.

Histoplasma capsulatum (H. capsulatum)is a thermal-dimorphic fungus, the causal agent of histoplasmosis. Its presence in the environment is related with chicken manure due to their high nitrogen and phosphorus content. In Colombia, chicken manure is the most used raw material in the composting process; however, there is no information about the capacity ofH. capsulatumto survive and remain viable in a composted organic fertilizer. To address this question, this study shows three assays based on microbiological culture and the Hc100 nested PCR. First, a composting reactor system was designed to transform organic material under laboratory conditions, and the raw material was inoculated with the fungus. From these reactors, the fungus was not isolated, but its DNA was detected. In the second assay, samples from factories where the DNA of the fungus was previously detected by PCR were analyzed. In the raw material samples, 3 colonies ofH. capsulatumwere isolated and its DNA was detected. However, after the composting process, neither the fungus was recovered by culture nor DNA was detected. In the third assay, sterilized and nonsterilized organic composted samples were inoculated withH. capsulatumand then evaluated monthly during a year. In both types of samples, the fungus DNA was detected by Hc100 nested PCR during the whole year, but the fungus only grew from sterile samples during the first two months evaluated. In general, the results of the assays showed thatH. capsulatumis not able to survive a well-done composting process.