A new culture medium for recovering the agents of Cryptococcosis from environmental sources

Silva, Dulcilena de Matos Castro e; Santos, Dayane Cristina Silva; Pukinskas, S. R. B. S.; Oshida, Julia T.U.; Oliveira, Lilian J.; Carvallho, Anderson F.; Melhem, Márcia de Souza Carvalho

doi:10.1590/s1517-838246220130726

Cited by 13 publications

(8 citation statements)

References 28 publications

(28 reference statements)

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“…A representative image (prepared using sample 17 from location 8) depicting cryptococcal brown colonies is shown ( Figure-5 ). These colonies were generated due to interactions between cryptococcal phenoloxidase and caffeic acid (melanin-producing substrate) in Niger seeds (one of the ingredients found in bird food) [ 21 ]. According to the literature, C. neoformans or C. gattii colonies are best characterized and visualized on bird seed agar [ 25 ].…”

Section: Resultsmentioning

confidence: 99%

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The first survey of cryptococcal cells in bird droppings across Bloemfontein, South Africa

et al. 2021

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Background and Aim: Cryptococcal yeast cells are spread across different ecosystems through bird movement and are deposited in bird guano. These cells may be inhaled by humans and lead to cryptococcal pneumonia. In individuals with reduced immune T-cell populations, cells may disseminate to the brain and cause the often-deadly cryptococcal meningitis. In this study, we surveyed cryptococcal cells in bird droppings across the city of Bloemfontein, South Africa. Materials and Methods: We aseptically collected 120 bird dropping samples from 15 representative city sites. In the laboratory, samples were assessed with regards to location, weighed, and standardized to a mass of 1 g before suspension in 10 mL phosphate buffer saline. Samples were first screened using Calcofluor-white stain as it is a rapid technique for the detection of fungi via binding to cell wall components such as chitin. After this, positive Calcofluor samples were serologically assayed for the cryptococcal antigen (CrAg). To confirm assay data, CrAg positive samples were then cultured on bird seed agar and resulting colonies were assessed using Indian ink. Results: We determined that 10/15 locations were positive for the CrAg. Pathogenic cells were identified on bird seed agar as brown colonies. When examined using microscopy, brown colony cells exhibited characteristic thick capsules representative of cryptococcal cells. Conclusion: This is the first proximate analysis showing the ecological distribution of cryptococcal cells in Bloemfontein. This is important as associated infections are acquired from the environment. Similarly, given the threat posed by cryptococcal cells to immunocompromised individuals, local authorities must initiate measures curbing the spread of these cells.

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Section: Resultsmentioning

confidence: 99%

“…We next recovered cells from positive samples in the CrAg immunoassay by cultivation on bird seed agar [ 21 ]. Media were prepared according to Atlas and Snyder [ 22 ].…”

Section: Methodsmentioning

confidence: 99%

The first survey of cryptococcal cells in bird droppings across Bloemfontein, South Africa

et al. 2021

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“…Sampling was executed using the M air T sampler (Millipore®, Merck KGaA, Germany) and Mas sampler (model 100, Merck®, Merck KGaA, Germany) ( Moura et al., 2015 ). The samples for fungi and bacteria were collected in clean, sterile plastic petri dishes with 20 mL of two different media: modified Dichloran Rose-Bengal Chloramphenicol Agar Medium (DRBCm) for fungal isolation, and Trypticase Soy Agar (TSB) for bacteria cultivation ( Castro e Silva et al., 2015 ), placed in each sampler for one hour (from 11 am, 12 pm and 1 pm for both devices), with a flow rate of 100 L min −1 , reaching a total air volume of 250 L. After sampling, the plates with DRBCm were incubated at 30° ± 2 °C for up to seven days for isolation and phenotypic identification ( Hoog et al., 2014 ). Each viable organism developed a colony, and after identification the number of colony-forming units (CFU) are expressed as concentration (CFU m −3 ).…”

Section: Methodsmentioning

confidence: 99%

Air pollution and its impact on the concentration of airborne fungi in the megacity of São Paulo, Brazil

Silva

Marcusso

Barbosa

et al. 2020

Heliyon

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In the context of megacities in an urban environment, air quality is an important issue, due to the direct correlation to population's health. The biomonitoring of pollutants can indicate subtle environmental alterations, for that, anemophilous fungi can be monitored for changes in atmospheric conditions related to pollution. In the present study, the concentration of fungi and bacteria in the atmosphere was measured during a specific vehicle fleet reduction in the city of São Paulo, Brazil, from May 24 to 30, 2018, using impactor air samplers. The number of isolated developed colonies was related to atmospheric conditions and the concentration of other air pollutants constantly monitored. Aspergillus, Curvularia, Penicillium, Neurospora, Rhizopus and Trichoderm a were identified. The number of colony-forming units increased by approximately 80% during the sampling period in response to environmental changes favored by the fleet reduction. This result implies the relation between fuel emissions, concentration of atmospheric pollutants, and the presence of viable fungal spores in the urban environment, which highlights the importance of combined public policies for air quality in large cities.

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“… 2014 ; de Matos Castro e Silva et al . 2015 ). Surveying and subsequent culturing can thus be labour and time-intensive and results in limited recovery rates (Vilcins et al .…”

Section: Challenges In Environmental Surveying and Modelling Cryptococcal Distributionsmentioning

confidence: 99%

The need for environmental surveillance to understand the ecology, epidemiology and impact of Cryptococcus infection in Africa

Edwards

Cogliati

Kwenda

et al. 2021

FEMS Microbiology Ecology

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Our understanding of the pathogenic yeasts Cryptococcus neoformans and Cryptococcus gattii has been greatly enhanced by use of genome sequencing technologies. Found ubiquitously as saprotrophs in the environment, inhalation of infectious spores from these pathogens can lead to the disease cryptococcosis. Individuals with compromised immune systems are at particular risk, most notably those living with HIV/AIDS. Genome sequencing in combination with laboratory and clinical studies has revealed diverse lineages with important differences in their observed frequency, virulence and clinical outcomes. However, to date, genomic analyses have focused primarily on clinical isolates that represent only a subset of the diversity in the environment. Enhanced genomic surveillance of these yeasts in their native environments is needed in order to understand their ecology, biology and evolution and how these influence the epidemiology and pathophysiology of clinical disease. This is particularly relevant on the African continent from where global cryptococcal diversity may have originated, yet where environmental sampling and sequencing has been sparse despite harbouring the largest population at risk from cryptococcosis. Here, we review what scientifically and clinically relevant insights have been provided by analysis of environmental Cryptococcus isolates to date and argue that with further sampling, particularly in Africa, many more important discoveries await.

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A new culture medium for recovering the agents of Cryptococcosis from environmental sources

Cited by 13 publications

References 28 publications

The first survey of cryptococcal cells in bird droppings across Bloemfontein, South Africa

The first survey of cryptococcal cells in bird droppings across Bloemfontein, South Africa

Air pollution and its impact on the concentration of airborne fungi in the megacity of São Paulo, Brazil

The need for environmental surveillance to understand the ecology, epidemiology and impact of Cryptococcus infection in Africa

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