Moldy buildings, health of their occupants and fungal prevention.

Microscopic fungi are important biological pollutants in the indoor environment, they are spread generally: on building materials, carpets, ceiling tiles, insulations, any surfaces, wallpapers, or in heating, ventilation, and air conditioning systems. Molds are able to grow on any materials, as long as moisture and oxygen are available. Exposure to fungi in indoor environments (esp. in water-damaged buildings) can cause adverse health effects, such as allergy, asthma, hypersensitivity pneumonia, mucous membrane irritation, different toxic effects, or even mycoses (in immunocompromised individuals) - alone or in combination. As serious adverse health effects could be caused antifungal prevention is an absolute need.This review article summarizes the occurrence of fungi in the indoor environment of buildings and their contribution to occupants´ health problems, and preventive measures against molds (Tab. 1, Fig. 1, Ref. 48).

The diversity of eukaryotic microbiota in the traditional Slovak sheep cheese--bryndza.

We investigated the occurrence and diversity of yeasts and filamentous fungi in bryndza an artisanal Slovak soft spreadable cheese prepared from raw sheep milk or from a mixture of sheep and cow milk. Samples collected during four months of the summer production period from two locations (northern and southern parts of central Slovakia) contained 10(5)-10(7) (cfu) yeasts and about 10(2) (cfu) of mold per gram of wet weight. Further characterization by conventional taxonomy and sequence comparison of D1/D2 region from 26S rRNA gene revealed Mucor circinelloides v. Tieghem as the predominant filamentous fungus. A novel Geotrichum sp. together with Kluyveromyces (K. lactis/K. marxianus) was identified as the most abundant yeast species. Occasionally other yeasts, such as Candida inconspicua, Candida silvae, Pichia fermentans and Trichosporon domesticum were found. Conventional taxonomy readily identified isolates to the genus level, but DNA sequence comparison was capable of discriminating them at the species level.

Antifungal activity of thyme (Thymus vulgaris L.) essential oil and thymol against moulds from damp dwellings.

AIMS: To characterize antifungal activities of essential oil of thyme (Thymus vulgaris L.) and pure thymol, as comparative substance, on different mould species isolated from damp dwellings. METHODS AND RESULTS: Fifty samples of wall scrapes were collected from damp dwellings in Zagreb, the capital of Croatia. The members of the following mould genera were recovered from the samples: Aspergillus (44%), Penicillium (18%) Alternaria, Ulocladium, Absidia and Mucor (8%) Cladosporium, Trichoderma and Rhizopus (6%), and Chaetomium (2%). Two strains of Stachybotrys chartarum were isolated from damp dwellings in Slovakia. Antifungal activities of the thyme essential oil, which contains p-cymene (36.5%), thymol (33.0%) and 1,8-cineole (11.3%) as main components, and pure thymol were determined by the dilution method and exposure to vaporous phase of the oil. Minimum inhibitory concentrations (MIC) of both thymol and essential oil were bellow 20 microg ml(-1), except for Mucor spp. (50.20 microg ml(-1)). Thymol exhibited approximately three-times stronger inhibition than essential oil of thyme. The vaporous phase of the thyme essential oil (82 microg l(-1)) in glass chambers strongly suppressed the sporulation of moulds during 60 days of exposure. CONCLUSION: The thyme essential oil possesses a wide range spectrum of fungicidal activity. The vaporous phase of the oil exhibited long-lasting suppressive activity on moulds from damp dwellings. SIGNIFICANCE AND IMPACT OF THE STUDY: Essential oil of thyme and thymol could be used for disinfection of mouldy walls in the dwellings in low concentration.

Penicillium implicatum causes a destructive rot of pomegranate fruits.

In this study Penicillium implicatum Biourge was found to be the cause of a destructive rot of stored pomegranate (Punica granata) fruits. This species has not previously been reported to cause disease of the fruit. The ability of the strain to decay pomegranates as well as some varieties of apples (Jonagold, Selena and Vanda) under laboratory conditions after inoculation with conidia into the subcutaneous layer of healthy fruits was demonstrated. The fungus was also found on mouldy stamens of pomegranates.

Isolation of fluconazole-tolerant micromycetes onto different cultivation media.

On studying the dependence of quality and/or quantity of environmental fluconazole-tolerant micromycetes on culture medium in vitro, the highest number of isolates was obtained in Sabouraud agar (SA) without fluconazole (59 CFU/mg of soil sample at 25 degrees C and 31 CFU/mg at 37 degrees C). In the case of SA, fluconazole inhibited the growth of micromycetes to 83%. Significant differences were found between the average concentration of CFU/mg for six cultivation media without and with fluconazole (70 mg/L) at 25 and 37 degrees C. The genus Aspergillus (A. flavus, A. fumigatus, aspergilli from A. glaucus and A. niger group, A. nidulans, A. versicolor, A. ustus), Scopulariopsis brevicaulis and Penicillium sp. were the most common isolates. Sabouraud agar combined with malt extract agar, dichloran-18% glycerol agar and potato-dextrose agar were the most suitable for isolation of fluconazole-tolerant fungi.

Growth modelling of heat-resistant fungi: the effect of water activity.

Growth of three strains of heat-resistant fungi, Byssochlamys fulva, Neosartorya fischeri and Talaromyces avellaneus, was studied at 25 degrees C at eight or nine water activities (a(w)) adjusted with sucrose between 0.995 and 0.85. The flexible growth model of Baranyi describing the change in colony diameter (mm) with respect to time was first fitted to measured growth data and from the fitted curves the maximum colony growth rates were estimated. These values were fitted with respect to a(w) to predict colony growth rates at any a(w) within the range tested. Optimum a(w) values of 0.986, 0.985, and 0.990 for growth, and maximum colony growth rates of 12.6, 13.2 and 20.2 mm d(-1), respectively, were calculated. The time to reach a colony diameter of 3 mm and the optimum a(w) for each strain were also calculated. The results can be applied to the prevention of spoilage of canned fruit or juices and other heat processed fruit based products.

Microscopic fungi in dwellings and their health implications in humans.

The article reviews the quantitative and qualitative incidence of microscopic filamentous fungi in dwellings, methods for their detection, mycotoxins, glucans and volatile organic compounds produced by microscopic fungi in the indoor air of homes. Characteristics and properties of the most important species of fungi in dwellings (Alternaria spp., Aspergillus spp., Cladosporium spp., Fusarium spp., Penicillium spp., Stachybotrys spp., and Wallemia spp.) and the health problems of occupants of the "moldy homes are also discussed.

Occurrence of itraconazole-tolerant micromycetes in the soil and food products.

Unexpected pathogens from the environment represent considerable risk for humans with impaired health. We examined the occurrence of itraconazole tolerant micromycetes in soil and in maize products. Five concentrations of itraconazole (2.5-12.5 micrograms/mL) selected according to known treatment schedules for human patients were incorporated into Sabouraud agar with chloramphenicol and Rose Bengal and diluted samples were inoculated onto the agar surface. After 7-d growth at 22 degrees C colonies of Alternaria sp., Aspergillus clavatus, A. glaucus group, A. flavus, A. fumigatus, A. niger group, A. ochraceus group, A. ochraceus, Chaetomium sp., Cladosporium cladosporioides, Cylindrocarpon sp., Doratomyces sp., Fusarium sp., F. moniliforme, F. oxysporum, F. solani, F. subglutinans, Marianaea elegans, Mortierella sp., Mucor sp., Myrothecium sp., Penicillium sp., Rhizopus sp., Scopulariopsis brevicaulis, Sepedonium sp., Stachybotrys chartarum, Stemphylium sp., Torula humicola and Trichoderma viride were isolated.

Antibiotic secondary metabolites of Dichotomomyces cejpii.

Nine fungal strains of Dichotomomyces cejpii were studied for their ability to produce antibiotic metabolites. It was found that they produced secondary exo- and endometabolites with antimicrobial activity against Gram-negative and Gram-positive bacteria, yeasts and moulds and with a toxic effect against animal organs in vitro. Detailed chemical characterization of these active principles need to be carried out.

Molds on house walls and the effect of their chloroform-extractable metabolites on the respiratory cilia movement of one-day-old chicks in vitro.

The ciliostatic activity of the chloroform-extractable endo- and exometabolites of 5 strains of filamentous fungi--Alternaria sp., Aspergillus glaucus group, Aspergillus versicolor, Cladosporium sphoerospermum, Penicillium sp. and Ulocladium sp.--isolated from molded walls of a dwelling--on tracheal cilia from 1-d-old chicks in vitro was evaluated. Endometabolites of Alternaria sp. and A. versicolor and exometabolites of Ulocladium sp. were the most active, these extracts stopped the ciliary movement within 1 d. The results are discussed in relation to the health status of people living in "moldy" dwellings.

Toxinogenicity of heat-resistant fungi detected by a bio-assay.

The ciliostatic activity of exo- and endometabolites of 125 (100%) heat-resistant fungal isolates was evaluated in vitro by a bioassay on tracheal tissue cultures of 1 day old chicks. For 11 (9%) of the isolates investigated chloroform-extractable secondary metabolites were detected in the medium. For 29 (23%) they were detected in mycelium and spores and for 25 (20%) they were detected in the medium, mycelium and spores at the same time. Especially Dichotomomyces cejpii and Eupenicillium baarnense strains displayed ciliostatic activity. Extracts of Gilmaniella humicola, Talaromyces avellaneus and Talaromyces bacillisporus isolates were not found ciliostatic in our experiment. The chloroform-extractable metabolites of Neosartorya fischeri ATCC 96469 and T. avellaneus ATCC 96465 strains had no ciliostatic activity, either, but G. humicola ATCC 96467 produced ciliostatic metabolites detected in the medium, the mycelia and the spores.

Ciliostatic effect of fungi on the respiratory tract ciliary movement of one-day-old chickens in vitro.

The ciliostatic activity of exo- and endometabolites of 243 filamentous fungal strains was evaluated by in vitro bioassay using tracheal organ cultures of 1-d-old chicks. Chloroform-extractable metabolites produced in the cultivation medium (25 degrees C/10 d) by 30 out of 72 (41%) investigated strains displayed the ciliostatic activity as did metabolites from the biomass of the spores and the mycelium of 46 other strains (26%). This result could contribute to the clarification of the correlation between fungi and respiratory disorders in some working places and in damp dwellings.

Filamentous microfungi in raw flax and cotton for textile industry and their ciliostatic activity on tracheal organ cultures in vitro.

In a three-year experiment we studied mycobiota of 24 samples of flax and 45 samples of cotton processed in Slovak textile factories. We isolated 12.2 x 10(6) (on average) cfu of microfungi per 1 g of flax samples and 3.3 x 10(5) (on average) cfu of micromycetes per 1 g of cotton samples. We also studied the ciliostatic activity of metabolites of isolated filamentous fungi on tracheal cultures of 1-day-old chicks in vitro. Twenty-nine percent of 116 investigated chloroform extracts of metabolites of microfungi isolated from flax samples stopped the cilia movement and 25% of 195 had ciliostatic activity during 72 h of experiment.

The effect of chloroform-extractable secondary metabolites of filamentous fungi on the movement of respiratory tract cilia of one-day-old chicks in vitro.

The ciliostatic activity of the chloroform-extractable metabolites of 72 strains of filamentous fungi growing in a liquid medium, on tracheal cilia from 1-d-old chicks in vitro was evaluated. Forty-eight of the investigated strains produced ciliostatic metabolites; 13, 11, 16, and 25% of the strains stopped the movement of cilia after 1, 2, 3, 6 d, respectively. The results are discussed in relationship with chronic bronchitis of people working with mouldy materials, living in mouldy dwellings and with the "sick-building syndrome".

Heat resistant fungi isolated from soil.

The Thermal death time values (TDT) were estimated for Dichotomomyces cejpii, Gilmaniella humicola, Talaromyces avellaneus and Talaromyces bacillisporus isolated from soil. TDT values were compared with the TDT values of the known heat-resistant species, Byssochlamys nivea, Neosartorya fischeri and Talaromyces flavus. All species studied showed considerable heat resistance. The most resistant species Talaromyces avellaneus (172 cfu, initial concentration) of the isolates with unknown heat resistance withstood 90 degrees C for 10 min. Byssochlamys nivea appeared to be the most sensitive species under our experimental conditions.

Heat resistance of fungi from soil.

The survival of fungi from soil samples has been investigated after exposure to temperatures of 60, 70, 80 and 90 degrees C in Sabouraud agar. The least resistant fungi surviving 60 degrees C for 60 min were the Aspergillus (A.) niger group, Chaetomium spp, Penicillium spp, and Scytalidium lignicola. None of these survived 70 degrees C for 10 min. The next group surviving 70 degrees C for 60 min included the A. glaucus group, Byssochlamys nivea, Dichotomomyces cejpii, Gelasinospora spp, Rhizoctonium spp, and Talaromyces flavus; they did not survive 80 degrees C for 10 min. At 80 degrees C for 60 min, survival was seen for Aspergillus fumigatus, Aspergillus nidulans, Eupenicillium baarnense and Ulocladium spp; they did not survive 10 min at 90 degrees C. Acremonium sclerotigenum, Aspergillus ochraceus, Botryotrichum piluliferum, Byssochlamys fulva, Gilmaniella humicola, Neosartorya fischeri, Nodulisporium sp. and Talaromyces avellaneus survived heat treatment at 90 degrees C for 10 min and longer time with the two last being the most resistant. The phenomen of activation of dormant spores by thermal shock was not apparent.

Heat-resistant fungi in the soil.

The occurrence of heat-resistant fungi has been demonstrated in samples of soil from the Slovak Republic. The heat-resistant species isolated were Byssochlamys nivea, Dichotomomyces cejpii, Eupenicillium baarnense, Neosartorya fischeri, Talaromyces avellaneus, Tal. bacillisporus, Tal. emersonii, Tal. flavus, Tal. trachyspermus, Tal. wortmanii, Botryotrichum piluliferum, Gilmaniella humicola and Nodulisporium sp. Some of them were isolated for the first time from Czechoslovakian soil. For the various soil samples examined, the occurrence of heat-resistant fungi varied qualitatively and quantitatively. Further research is needed to identify conditions affecting the occurrence of heat-resistant fungi in soil.