Maria Dynowska

Mallard duck (Anas platyrhynchos) as a potential link in the epidemiological chain mycoses originating from water reservoirs

Abstract Swabs sampled from beaks and cloaca of 123 live Mallard ducks (also referred to as wild ducks) were subjected to routine mycological diagnostics. Out of 246 samples analysed, positive results were noted in 210 (85.4%) cases. The taxonomic analysis revealed 30 species of yeast and yeast-like fungi and 24 species of mould fungi, included 35 classified to BSL categories. The most frequently isolated species were: Candida albicans, C. guilliermondii, C. krusei, Cryptococcus neoformans, Cr. laurentii, Rhodotorula rubra, Saccharomyces cerevisiae, Aspergillus fumigatus, A. flavus, A. niger, and Fusarium solani. The results demonstrated that wild duck breeding in the proximate vicinity of man constitutes a rich reservoir of potentially-pathogenic fungi and a significant link in epidemiology of many mycotic diseases.

Snow in the city as a spore bank of potentially pathogenic fungi.

This study evaluates the role of snow as a specific ecological niche and a vector in fungal spreading with particular emphasis on potential pathogens in seasonally and daily changing conditions. The experimental material was fungi isolated from the atmospheric air, snow cover, and fragments of ice and soil from underneath the snow cover. The total count of microfungi in the air before snowfall, i.e. in the autumn, reached 1756.1 CFU/m(3) on average. After the first snowfalls, it dropped to 85.2 CFU/m(3). The analyzed samples of snow cover contained from 101.6 to 8500.0 CFU/m(3) of fungi. Furthermore, 26 species of yeast and yeast-like fungi were isolated from the experimental material. Amongst the analyzed species, 13 were potential anthropopathogens. Though another three species were isolated from organ ontocenoses, i.e. Candida intermedia, Saccharomyces bayanus and Zygosaccharomyces rouxii, their pathogenic potential has not yet been explicitly confirmed. The results of the presented study may be applied in predicting concentrations of fungal spores responsible for mycoses. The first snowfalls significantly reduced the number of colony-forming units of fungi in the air. Under conditions of temperate climate, snow becomes a temporary bank of yeast-like fungi spores and while it melts cells of deposited microfungi migrate to the atmosphere. Hence, individuals with impaired immunity or in the course of immunosuppression or recovery should avoid long walks during periods of snow melting. The count of fungi in urban bioaerosol during the melt may be reduced through systematic removal of snow cover, which is a significant reservoir of potential pathogens. In addition, it should be noted that even a typical psychrophilic strain, capable of surviving at a temperature of 37°C, may bear a significant pathogenic potential.

Epidemiological Importance of Yeasts Isolated from the Beak and Cloaca of Healthy Charadriiformes

Abstract The paper presents mycological studies conducted jointly with ornithologists on the epidemiology of mycoses and the taxonomic diversity and prevalence of fungi that colonise the selected onthocenoses in healthy, wild migratory birds. Aquatic ecosystem populations of healthy birds include a percentage of carriers of potential zoo- and anthropopathogens, and this studys purpose was to determine the percentage. The studies were performed on swabs sampled in vivo (during spring and autumn migrations) from the beak and cloaca of nine species of Charadriiformes in two age categories. Macro- and microcultures of fungi were prepared according to the standards for diagnostic mycological laboratories. From the 450 birds examined, fungi were isolated from 130 (26.5%) individuals. The sampling yielded 272 yeast isolates: 170 (62.5%) from the beak and 102 (37.5%) from the cloaca. The isolates represented 23 species, among which C. albicans, C. neoformans, and R. rubra were predominant. In both onthocenoses in young and adult birds, more fungi were recorded in autumn than in spring. As many as 15 species are included in the biosafety level classification, of which seven are categorised as category 2 and one as category 3.

Black-headed gulls ( Chroicocephalus ridibundus ) - a natural reservoir of potentially pathogenic microfungi?

Mycological studies of selected populations of black-headed gulls were carried out in response to the increasing interest in wild birds as reservoirs of potentially pathogenic fungi and links in the epidemiological chain of mycoses hazardous to human and animals. The biological material comprised swabs from the beaks and cloacae of adult and young birds subjected to standard mycological diagnostics. 79.5% of samples were positive, comprising 22 fungal species belonging to 10 genera, mainly Candida, Rhodotorula, Aspergillus, Fusarium, Cryptococcus, and Trichosporon. The most frequently isolated species were Candida albicans and Rhodotorula rubra, found in the beaks of females and young birds and in the cloacae of young birds with comparable frequency. Cryptococcus laurentii, Cr. neoformans, Aspergillus niger, A. flavus, and Rh. muscilaginosa were isolated relatively frequently from all birds. The results highlight the ecological importance of wild birds in the circulation of potentially pathogenic fungi in the biosphere.

Human Mycobiota-Selected Ontocenoses of Students of Natural Science andMedicine

Objectives: The aim of this study was to compare the prevalence of yeast-like fungi and yeasts on the mucous membranes of a group of students of Natural Sciences and Medicine. Materials and methods: The study involved 156 students of the Faculty of Biology and Biotechnology (FB&B) and 37 students of the Faculty of Medical Sciences (FMS). Material samples were collected with sterile cotton swab from the nose, mouth and throat. The identification of fungi was carried out by the evaluation of macrocultures and microcultures on Nickerson agar and biochemical features. Results: Yeast-like fungi and yeast were isolated from 41.97% of the subjects (81 people). The fungal colonization of the mucous membrane was observed in 59 students of the Faculty of Biology and Biotechnology (37.82%) and 22 students (56.46%) of the Faculty of Medical Sciences. The obtained fungi were classified into 31 taxonomic units. The predominant species were Candida dubliniensis and Lachancea thermotolerans (syn. Kluyveromyces thermotolerans). 14 species with defined status of BSL were recorded. Conclusions: Yeast and yeast-like fungi were more frequent among students of Biology and Biotechnology, than students of Medical Sciences. In students of FB&B greater taxonomic diversity of fungi was found than in students of FMS. The species diversity and prevalence of fungi observed in students of the Life Sciences are determined not only by lifestyle, but mainly by the possibility and frequency of contact with a variety of reservoirs and sources of potentially pathogenic fungi. The occurrence in human ontocenoses of 14 species classified to 1st and 2nd class of Biosafety Level is also very important.