A medium for inducing conversion of Histoplasma capsulatum var. capsulatum into its yeast-like form

Fressatti, R.; Dias-Siqueira, V. L.; Svidzinski, Terezinha Inez Estivalet; Herrero, Francisco Sanz; Kemmelmeier, Carlos

doi:10.1590/s0074-02761992000100010

Cited by 6 publications

(5 citation statements)

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“…Two slant tubes of each medium were used to improve the odds of H. capsulatum isolation. If putative Histoplasma colonies grew, they would be subcultured in ML-Gema agar medium [ 11 ], for 7 to 14 days at 37 °C for dimorphism confirmation.…”

Section: Methodsmentioning

confidence: 99%

Acute Pulmonary Histoplasmosis Following COVID-19: Novel Laboratorial Methods Aiding Diagnosis

Macedo¹,

Freitas²,

Bártholo

et al. 2021

JoF

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The acute form of histoplasmosis usually occurs after the exposition of more than one individual to a common environmental source harboring Histoplasma capsulatum. Here, we present two cases of acute pulmonary histoplasmosis seen within two weeks at a reference center for infectious diseases at Rio de Janeiro, Brazil. The patients did not present a common epidemiologic history for histoplasmosis, however both presented COVID-19 before the onset of histoplasmosis symptoms. Due to the difficulties in the diagnosis of acute histoplasmosis, novel laboratory methods such as Western Blot and PCR were included in the investigation of these cases. Both patients presented negative cultures for H. capsulatum and negative urinary galactomannan. However, they presented H and M bands in the Western blot as well as a positive H. capsulatum DNA detection in sputum. These results were available approximately 36 h after sample collection, fastening the beginning of treatment of one patient. Both patients progressed well with itraconazole treatment. These cases suggest that COVID-19 may facilitate the development of acute pulmonary histoplasmosis and, therefore, clinicians must be aware of this differential diagnosis in patients from endemic areas with fever and coughing after recovery from COVID-19.

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Section: Methodsmentioning

confidence: 99%

Acute Pulmonary Histoplasmosis Following COVID-19: Novel Laboratorial Methods Aiding Diagnosis

Macedo¹,

Freitas²,

Bártholo

et al. 2021

JoF

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“…A total of 500 µl of YP/MP liquid cultures were used for DNA extraction. Briefly, the cells were harvested by centrifugation, washed three times with distilled deionized water, and kept at −4 °C for DNA extraction as previously described 43 . DNA was quantified by spectrophotometry using the Epoch™ Multi-Volume Spectrophotometer System (Biotek Instruments, Inc., USA).…”

Section: Methodsmentioning

confidence: 99%

“…Micromorphological characteristics of MP were observed by optical microscopy (Zeiss PrimoStar, Oberkochen, Germany) by sampling 10 fields randomly with a magnification of 400X, after Lactophenol Cotton Blue (Fluka Analyted, France) staining. Dimorphism was demonstrated by MP-YP conversion in the ML-Gema Agar at 37 °C, for 7 to 14 days 43 .…”

Section: Methodsmentioning

confidence: 99%

Novel clinical and dual infection by Histoplasma capsulatum genotypes in HIV patients from Northeastern, Brazil

Damasceno¹,

Teixeira

Barker

et al. 2019

Sci Rep

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Histoplasmosis is a worldwide-distributed deep mycosis that affects healthy and immunocompromised hosts. Severe and disseminated disease is especially common in HIV-infected patients. At least 11 phylogenetic species are recognized and the majority of diversity is found in Latin America. The northeastern region of Brazil has one of the highest HIV/AIDS prevalence in Latin America and Ceará State has one of the highest death rates due to histoplasmosis in the world, where the mortality rate varies between 33–42%. The phylogenetic distribution and population genetic structure of 51 clinical isolates from Northeast Brazil was studied. For that morphological characteristics, exoantigens profile, and fungal mating types were evaluated. The genotypes were deduced by a MSLT in order to define local population structure of this fungal pathogen. In addition, the relationships of H . capsulatum genotypes with clinically relevant phenotypes and clinical aspects were investigated. The results suggest two cryptic species, herein named population Northeast BR1 and population Northeast BR2. These populations are recombining, exhibit a high level of haplotype diversity, and contain different ratios of mating types MAT1-1 and MAT1-2 . However, differences in phenotypes or clinical aspects were not observed within these new cryptic species. A HIV patient can be co-infected by two or more genotypes from Northeast BR1 and/or Northeast BR2, which may have significant impact on disease progression due to the impaired immune response. We hypothesize that co-infections could be the result of multiple exposure events and may indicate higher risk of disseminated histoplasmosis, especially in HIV infected patients.

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“…All isolates are maintained at the INI/Fiocruz fungal collection. Fungal strains were kept in the mycelial form on Potato Dextrose Agar (PDA) (Becton, Dickinson and Company, Sparks, MD, USA) at 25 °C, and the dimorphism was demonstrated by conversion to the yeast-like form on ML-Gema agar medium [ 25 ] at 37 °C.…”

Section: Methodsmentioning

confidence: 99%

Mebendazole Inhibits Histoplasma capsulatum In Vitro Growth and Decreases Mitochondrion and Cytoskeleton Protein Levels

Almeida

Bernardes-Engemann

Coelho

et al. 2023

JoF

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Histoplasmosis is a frequent mycosis in people living with HIV/AIDS and other immunocompromised hosts. Histoplasmosis has high rates of mortality in these patients if treatment is unsuccessful. Itraconazole and amphotericin B are used to treat histoplasmosis; however, both antifungals have potentially severe pharmacokinetic drug interactions and toxicity. The present study determined the minimal inhibitory and fungicidal concentrations of mebendazole, a drug present in the NIH Clinical Collection, to establish whether it has fungicidal or fungistatic activity against Histoplasma capsulatum. Protein extracts from H. capsulatum yeasts, treated or not with mebendazole, were analyzed by proteomics to understand the metabolic changes driven by this benzimidazole. Mebendazole inhibited the growth of 10 H. capsulatum strains, presenting minimal inhibitory concentrations ranging from 5.0 to 0.08 µM. Proteomics revealed 30 and 18 proteins exclusively detected in untreated and mebendazole-treated H. capsulatum yeast cells, respectively. Proteins related to the tricarboxylic acid cycle, cytoskeleton, and ribosomes were highly abundant in untreated cells. Proteins related to the nitrogen, sulfur, and pyrimidine metabolisms were enriched in mebendazole-treated cells. Furthermore, mebendazole was able to inhibit the oxidative metabolism, disrupt the cytoskeleton, and decrease ribosomal proteins in H. capsulatum. These results suggest mebendazole as a drug to be repurposed for histoplasmosis treatment.

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A medium for inducing conversion of Histoplasma capsulatum var. capsulatum into its yeast-like form

Cited by 6 publications

References 0 publications

Acute Pulmonary Histoplasmosis Following COVID-19: Novel Laboratorial Methods Aiding Diagnosis

Acute Pulmonary Histoplasmosis Following COVID-19: Novel Laboratorial Methods Aiding Diagnosis

Novel clinical and dual infection by Histoplasma capsulatum genotypes in HIV patients from Northeastern, Brazil

Mebendazole Inhibits Histoplasma capsulatum In Vitro Growth and Decreases Mitochondrion and Cytoskeleton Protein Levels

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