Incidence of allergenically significant fungal aerosol in a rural bakery of West Bengal,India

The frequency of fungal spores in the air of three different sections of a rural bakery was analyzed using a Burkard personal slide sampler and Andersen two stage viable sampler. In average concentration of spores (No./m³) was 228–26770/m³ and concentration of viable colony forming units (CFU/m³) was 65-2061 CFU/m³. Dominant fungus species both culturable and nonculturable, were species of Aspergillus and Penicillium, Cladosporiumsp., Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Cladosporium cladosporioides, Penicillium citrinum and Alternaria alternata. Seasonal variations in the spore concentrations were clearly observed in case of some fungi. Total culturable mould concentration of different bakery sections sometimes exceeded the acceptable limit for a healthy indoor environment. Antigenic extracts prepared from some dominant culturable fungi showed high level of allergenicity in skin prick tests indicating that they could be responsible for allergic respiratory dysfunction of bakery workers.This revised version was published online in October 2005 with corrections to the Cover Date.     

Airborne concentrations of bacteria and fungi in Thailand border market

Thailand border market is where the local Thais, Cambodians, Laotians, and Burmeses exchange their goods and culture at the border checkpoints. It is considered to be the source of aerial disease transmission especially for foreigners because it is always very crowded with people from all walks of life. Unhealthy air quality makes this area high risk of spread of airborne diseases. This study assessed airborne concentrations of bacteria and fungi in a border market to improve exposure estimates and develop efficient control strategies to reduce health risk. The density and distribution of airborne bacteria and fungi were investigated in the Chong Chom border market in Surin Province, Thailand. Eighteen air sampling sites were taken from outdoors and various work environments including indoor footpaths, wooden handicraft shops, electronic shops, the secondhand clothing shops, and fruit market areas. Exposed Petri plate method and liquid impinger sampler were used for sampling at the breathing zone, 1.5 m above the floor level, during weekend and holiday. Meteorological factors such as relative humidity, temperature, and light intensity were collected by portable data logger. The relative humidity was 67–73%, and temperature 29–33°C, and light varied between 18 and 270 Lux m⁻². Gram-positive and Gram-negative bacteria were found at a mean value of 10⁴ CFU m⁻³, and airborne fungi of 10³ CFU m⁻³ were recorded. The highest concentration of culturable airborne microorganisms was found along the indoor footpath (9.62 × 10⁴ CFU m⁻³ and 750.00 CFU/plate/h for impingement and sedimentation methods, respectively), the fruit market area (7.86 × 10⁴ CFU m⁻³ and 592.42 CFU/plate/h for impingement and sedimentation methods, respectively), and the secondhand clothing shop (4.59 × 10³ CFU m⁻³ and 335.42 CFU/plate/h for impingement and sedimentation methods, respectively) for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The lowest concentration of Gram-positive bacteria, Gram-negative bacteria, and fungi was found only at the outdoor area at 1.53 × 10⁴ CFU m⁻³, 0.93 × 10⁴ CFU m⁻³ and 0.80 × 10³ CFU m⁻³ by means of impingement method and 136.67 CFU/plate/h, 69.25 CFU/plate/h, and 62.00 CFU/plate/h by means of sedimentation methods for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The most frequently present airborne bacteria were identified as Bacillus, Corynebacteria, Diplococcus, Micrococcus, Acinetobacter, Alcaligenes, Enterobacter, and spore former rods. Acremonium, Aspergillus, Cladosporium, Penicillium, and Sporotrichum were the most frequently found aerosol fungi genera. The distribution of airborne microorganisms correlated with relative humidity and light factors based on principal component analysis. In conclusion, the border market is a potential source of aerial disease transmission and a various hazards of bioaerosols for workers, consumers, sellers, and tourists. The bioaerosol concentration exceeded the standard of occupational exposure limit. Many major indicators of allergenic and toxigenic airborne bacteria and fungi, Acinetobacter, Enterobacter, Pseudomonas, Cladosporium, Alternaria, Aspergillus, and Penicillium, were found in the various market environments.     

Assessment of bioaerosols at a concentrated dairy operation

Increased bioaerosol loadings in downwind plumes from concentrated animal feeding operations (CAFOs) may increase the risk for allergy and infection in humans. In this study, we monitored airborne concentrations of culturable bacteria and fungi at upwind (background) and downwind sites at a 10,000 milking cow dairy over the course of a year. The average bacterial concentrations at the upwind site were 8.4 × 10³ colony forming units (CFU) m⁻³ and increased to 9.9 × 10⁵ CFU m⁻³ at the downwind edge of the cattle lots, decreasing to 6.3 × 10⁴ CFU m⁻³ 200 m farther downwind. At the same sites, the average fungal concentrations were 515, 945, and 1,010 CFU m⁻³, respectively. Significant correlations between the ambient weather conditions and airborne fungal and bacterial concentrations were identified. Sequence analysis of PCR-amplified DNA from bacterial clones and fungal isolates revealed genus and species level differences between upwind and downwind sites. Although we could not cultivate gram-negative bacteria, bacterial clones at downwind sites identified as being gram-negative matched with the following genera: Acinetobacter, Bradyrhizobium, Escherichia, Idiomarina, Methylobacterium, Ralstonia, and Novosphingobium. Fungal isolates from downwind matched with the following genera: Acremonium, Alternaria, Ascomycte, Aspergillus, Basidiomycete, Cladosporium, Davidiella, Doratomyces, Emericella, Lewia, Onygenales, Penicillium, Rhizopus, and Ulocladium. None of the bacterial and fungal sequence matches were affiliated with genera and species known to be pathogenic to humans. Overall, the data suggest that exposure to bioaerosols in the downwind environment decreases with increasing distance from the open-lot dairy.     

Aerobiological,biochemical and immunological studies on some of the dominant <Emphasis Type="Italic">Aspergillus</Emphasis> species of South Assam (India)

Two years atmospheric survey of air-borne Aspergillus was carried out in the environmental conditions of South Assam. The survey revealed a total of 16 different species of Aspergillus with marked seasonal and annual variations. Aspergillus fumigatus was found to be the dominant atmospheric fungal species followed by Aspergillus flavus, Aspergillus niger, etc. Among the sample extracts tested, highest quantity of soluble protein was recorded in Aspergillus fumigatus (95.0 mg/g) whereas highest quantity of soluble carbohydrate (40.8 mg/g) and free amino acid (135.0 mg/g) was recorded in the sample extract of Aspergillus niger per gram of dry weight, respectively. The highest numbers of protein polypeptide bands were detected in the sample extract of Aspergillus fumigatus followed by Aspergillus flavus and lowest in Aspergillus niger. The maximum numbers of immunoglobulin E binding protein fractions were found in Aspergillus fumigatus, followed by Aspergillus flavus, Aspergillus clavatus, etc.     

Air biocontamination in a variety of agricultural industry environments in Egypt: a pilot study

Inhalation of airborne microorganisms and organic dust is an occupational concern among workers in agricultural industries. Airborne microorganisms and particulate matter samples were collected from poultry house, flourmill, textile, and food industry sites by use of liquid impinger and gravimetric samplers. Particulate matter concentrations were recorded at median concentrations of 1.56, 1.92, 4.39, and 0.7 mg/m³ in the occupied poultry house, textile, flourmill, and food indoor working environments, respectively. The highest median particulate matter concentration (27.9 mg/m³) was detected at the flourmill’s stack site. The highest median indoor concentration of culturable airborne bacteria (6.23 × 10⁵ CFU/m³) was found at the occupied poultry-house site and the lowest concentration (4.6 × 10³ CFU/m³) was found at the food industry site. The highest median indoor concentration of culturable airborne fungi (3.15 × 10⁴ CFU/m³) was found at the flourmill site whereas the lowest (1.24 × 10³ CFU/m³) was found at the textile industry site. Bacillus and Staphylococcus were the predominant Gram-positive bacteria whereas Acinetobacter and Klebsiella were the predominant Gram-negative bacteria. Escherichia coli and Salmonella were only detected in the indoor air at the poultry house site. Aspergillus flavus, Aspergillus niger, Penicillium, and yeast were the predominant fungal types at flourmill, textile, food industry, and poultry house, respectively. Workers were continuously exposed to airborne microorganisms at a median value of 10⁴ CFU/m³ in all the industries studied.     

Especies de Aspergillus en ambientes hospitalarios con pacientes pediátricos en estado crítico

BackgroundAspergillus is a group of opportunistic fungi that cause infections, with high morbimortality in immunosuppressed patients. Aspergillus fumigatus is the most frequent species in these infections, although the incidence of other species has increased in the last few years.AimsTo evaluate the air fungal load and the diversity of Aspergillus species in hospitals with pediatric patients in critical condition.MethodsThe Intensive Care Unit and Burns Unit of a pediatric hospital were sampled every 15 days during the autumn and spring seasons. The air samples were collected with SAS Super 100^® and the surface samples were collected by swab method.ResultsThe UFC/m³ counts found exceeded the acceptable levels. The UFC/m³ and the diversity of Aspergillus species found in the Intensive Care Unit were higher than those found in the Burns Unit. The fungal load and the diversity of species within the units were higher than those in control environments. The use of both methods –SAS and swab– allowed the detection of a higher diversity of species, with 96 strains of Aspergillus being isolated and 12 species identified. The outstanding findings were Aspergillus sydowii, Aspergillus niger, Aspergillus flavus, Aspergillus terreus and Aspergillus parasiticus, due to their high frequency. Aspergillus fumigatus, considered unacceptable in indoor environments, was isolated in both units.ConclusionsAspergillus was present with high frequency in these units. Several species are of interest in public health for being potential pathogenic agents. Air control and monitoring are essential in the prevention of these infections.     

Indoor and outdoor airborne fungal propagule concentrations in Mexico City

Thirty homes of asthmatic adults located in Mexico City were examined to determine the predominant culturable fungi and the changes in their airborne concentrations. Fungi were cultured and identified microscopically from air samples collected in naturally ventilated homes, during both wet (July–August) and cool dry (November–December) seasons, and from settled dust from the same homes. Airborne dust from indoor yielded 99–4950 cfu m⁻³, and settled dust 10²–10⁶ cfu g⁻¹ on DG18 agar. The indoor geometric mean concentration of airborne fungi during the cool dry season was 460 cfu m⁻³ while in the wet season it was 141 cfu m⁻³. Similarly, numbers of airborne fungal propagules out of doors decreased 60% between the dry and wet season. In general, the total fungal concentrations in indoor air were less than 10³ cfu m⁻³ and a large proportion of them was collected in Stage-2 of the Andersen sampler. Moreover, the ratio between indoor and outdoor concentrations was <3:1. Five of the 30 sampled homes yielded >500 cfu m⁻³ of one genus, with up to 1493Cladosporium cfu m⁻³ or 2549Penicillium cfu m⁻³. Also, these two genera were predominant in both airborne and settled dust, and their concentrations were greater indoors than out, indicating a possible indoor source of fungal propagules. The predominant species wereCladosporium herbarum, Penicillium aurantiogriseum andP. chrysogenum. These results suggest that exposure to large concentrations of fungi occurs indoors and is associated with both seasons of the year and with particular home characteristics.     

Airborne fungi associated with ornamental plant propagation in greenhouses

The objective was to determine potential exposure to airborne fungi in greenhouses and to characterize the temporal patterns of airborne fungi in relation to environmental conditions. We analyzed air samples collected in two greenhouses. Results showed that the top 5 fungi in greenhouse 1 were Trichoderma, hyphal fragments, Aspergillus/Penicillium-like, Cladosporium, and Botrytis in a descending order. Those in greenhouse 2 were Aspergillus/Penicillium-like, Cladosporium, Botrytis, yeast-like, and hyphal fragments. Maximum concentrations of Trichoderma and total spores in greenhouse 1 were 36,426 and 49,729 spores/m³, respectively. Maximum concentrations of Aspergillus/Penicillium and total spores in greenhouse 2 were 46,961 and 71,037 spores/m³, respectively. Airborne fungal populations fluctuated dramatically within 2 h during work hours, tenfold for Aspergillus/Penicillium, 66-fold for Trichoderma, and sevenfold for total spores. QPCR detected Trichoderma harzianum ranging from 7 to 3,500 conidia E/m³. Aspergillus/Penicillium and Botrytis showed diurnal patterns, but not Trichoderma. Aspergillus/Penicillium and Cladosporium were positively correlated with temperature, relative humidity, dew point, heat index, and light and negatively with air movement and air pressure. Botrytis and Trichoderma were not correlated with the environmental factors. Greenhouse workers were potentially exposed up to 71,037 spores/m³ of airborne fungi.     

Quantification of airborne Aspergillus fumigatus spores in rabbit houses by real-time polymerase chain reaction

To accurately quantify airborne Aspergillus fumigatus (A. fumigatus) spores in rabbit houses, the real-time polymerase chain reaction (real-time PCR) and culture-based counting method (CCM) were employed to determine the airborne A. fumigatus spore concentrations. The results showed that, of the three rabbit houses (A, B, and C), the average concentrations of airborne A. fumigatus spores determined by real-time PCR were 3.0 × 10³, 3.3 × 10³, and 1.5 × 10³ spores/m³ air, respectively, while those determined by CCM were 2.5 × 10², 2.8 × 10², and 1.1 × 10² colony-forming unit/m³ air (CFU/m³ air), respectively, i.e., the former concentration was 12–14 times higher than the latter one. Therefore, the conventional CCM underestimated the concentrations of airborne fungal spores, and it is insufficient to determine the microbial aerosol concentration and evaluate the health risk only using CCM.     

Airborne dust,bacteria, actinomycetes and fungi at a flourmill

A study was carried out on suspended dust, bacterial and fungal aerosols in a four-storey flourmill building located in Giza, Egypt. Airborne microorganisms were quantitatively isolated using liquid impinger and gravimetric samplers during the period from March 2004 to February 2005. Suspended dust varied from 1.96 to 16.3 mg m⁻³ and 0.69 to 1.8 mg m⁻³ in the indoor and outdoor environments, respectively. Suspended dust was significantly greater (P < 0.05) at bran package, double roller, purifiers and flour storage units in comparison to the outdoor reference site. The dust levels exceed the occupational exposure limit (OEL) of 0.5 mg m⁻³ for flour dust. Airborne microbial counts were found at median values, between sampling locations, ranged from 0 to >10⁴ CFU m⁻³. Gram-negative bacteria were found in small numbers (0–10² CFU m⁻³). The highest concentration of actinomycetes (>10³ CFU m⁻³) was detected in the storage unit. Airborne fungal counts were found at the median values, between sampling locations, varied from 10³ to 10⁴ CFU m⁻³. The counts of airborne bacteria and fungi were significantly greater (P < 0.05) at the purifiers and double roller mill units in comparison to the outdoor reference site using the liquid impinger sampler. Microbial levels associated with bulk deposited dust averaged between 10⁵ and 10⁶ CFU g⁻¹. Alcaligenes (5.4%) Pseudomonas (3.87%) and Enterobacter (3.1%) were the predominant Gram-negative species while Bacillus (29.4%) and Micrococci (13.9%) were the major components of Gram-positive bacteria. Aspergillus and Penicillium were the predominant fungal types indoor whereas Cladosporium (35.2%) and Aspergillus species (22.2%) were the predominant fungal types outdoor. A number of allergenic and toxigenic bioaerosols were found in the flourmill workplace.     

Aspergillus and other moulds in the air of Kuwait

A one-year survey was carried out to study the aerial prevalence of Aspergillus species and other moulds in the outdoor and indoor environments of Kuwait. Petri plates containing rose-Bengal medium were exposed for 20 minutes twice a month using a six-stage Andersen air sampler at the pre-determined sites. The exposed plates were incubated at 28 °C ± 1 °C up to 5 days and colonies were enumerated and identified by colonial and microscopic morphology. The data revealed that Aspergillus species were the predominant component (27.7%) of the outdoor aerospora of Kuwait and A. fumigatus alone accounted for 21.3% of the total aspergilli. In contrast, Cladosporium species formed the major component of the indoor aerospora (22.8%), followed by Aspergillus species (20.9%), Penicillium species (14.6%), and Bipolaris species (10.6%). A comparison of the fungi recorded in the outdoor and in the indoor air revealed that Aspergillus, Alternaria and Fusarium were significantly higher in the outdoor environment, whereas Cladosporium, Penicillium, and Bipolaris were significantly higher in the indoor environment. The relative prevalence of Aspergillus species and other moulds in the outdoor and indoor air of Kuwait was as follows: A. fumigatus 5.9 and 9.8%, A. flavus 4.9 and 3.9%, other aspergilli 16.8 and 7.0%, Alternaria species 19.8 and 7.9%, Cladosporium species 13.7 and 22.8%, Penicillium species 7.6 and 14.6%, and other moulds 31.2 and 34.1%, respectively. During the study, 25 different genera were identified, indicating a wide diversity in the spectrum of local fungal aerospora. The study provides useful information on the prevalence of allergenic fungi in the outdoor and indoor environments of Kuwait. This revised version was published online in June 2006 with corrections to the Cover Date.     

Aerobiological monitoring of Aspergillus/Penicillium spores during the potato storage

Aerobiological studies are widely used to determine the fungal spectrum in the air. These studies have revealed that Aspergillus/Penicillium spores are the most abundant spores in both outdoor and indoor environments. In this study, we have presented the variations in the concentration of these spores in an indoor environment (a potato store). Aerobiological sampling was conducted during five storage period (from 2002 to 2008 year) using a Hirst-type spore trap. The maximum spore concentrations were counted during the second fortnight of January and in the months of February and March, with values higher than 6,000 spores/m³ per day. A correlation analysis between the Aspergillus/Penicillium spores and the main environmental parameters was performed; significant coefficients were obtained for spores present in the store previous days and mean temperature of the same day and previous days (P < 0.001). Moreover, a regression model was established and predicted 53% variability of the data included in the analysis. The best obtained model took into account the Aspergillus/Penicillium spore type levels of 1 previous day and the mean temperature in the preceding 2 days.     

Status of airborne spores and pollen in a coir factory in Kerala,India

The prevalence of airborne fungal spores and pollen grains in the indoor and outdoor environments of a coir factory in Thiruvananthapuram district of Kerala state, India was studied using the Burkard Personal Sampler and the Andersen 2-stage Sampler for 2 years (September 1997 to August 1999). The concentration of pollen grains was remarkably lower than that of fungal spores (ratio of 1:28). There was no large difference in the concentrations and types of fungal spores between the indoor and outdoor environments, with 26 spore types found to be present indoors and 27 types outdoors; of these, 22 were common to both the environments. Aspergillus/Penicillium, Cladosporium, ‘other basidiospores’ and ascospores were the dominant spore types. The total spore concentration was highest in February and lowest in September, and it was significantly higher in 1998–1999 than in 1997–1998. Twenty viable colony-forming types were isolated from inside the coir factory. The most dominant viable fungi isolated were Penicillium citrinum, Aspergillus flavus and Aspergillus niger. The total pollen concentration was higher in the outdoor environment of the coir factory than indoors, with 15 and 17 pollen types, respectively. Grass and Cocos nucifera pollen types were dominant. The dominant spore and pollen types trapped in the two environments of the coir factory are reportedly allergenic and, consequently, workers are at risk of catching respiratory/allergic diseases.     

Continually Measured Fungal Profiles in Sick Building Syndrome

Buildings with indoor air quality (IAQ) complaints frequently have high airborne concentrations of Penicillium species, while buildings with few IAQ complaints have an indoor air (IDA) fungal ecology similar to outdoor air (ODA), where Cladosporium species is usually the dominant microorganism. These studies compared fungal air profiles, measured continually over 6 h in a documented sick building, in IDA in a room experiencing IAQ problems with fungal profiles measured concurrently in ODA. The dominant species collected at both sites were Penicillium species, Cladosporium species, and Alternaria species. In the IDA, Penicillium species were always the dominant organisms, ranging from 150 to 567 cfu/m³ (89.8–100% of the total fungi). In the ODA, Cladosporium species were dominant in four samples (40.0–70.6%), while Penicillium species were dominant (52.7–79.6%) in two. These data demonstrate that, even though ODA fungal profiles are changing continuously, IDA fungal profiles in “sick” buildings tend to remain unchanged. Received: 6 July 1998 / Accepted: 12 August 1998     

Composition and variability of airborne fungi in an enclosed rabbit house in China

Sampling was conducted from June 2007 to May 2008 in an enclosed rabbit house to investigate composition and variability of airborne fungi. Samples were collected using an Andersen-6 sampler, with Sabouraud culture medium as sampling medium. The results showed that monthly mean concentration was 2.79–5.46 × 10³ colony forming unit/m³ air (CFU/m³ air), with the maximum level in October, and the minimum level in January. Within a day, the maximum level occurred at 09:00, followed by 17:00 and then 13:00. A total of 6,523 fungal colonies, belonging to 17 genera and 36 species, were obtained. The predominant genera included Cladosporium, Penicillium, Aspergillus and Altemaria, comprising 71.45% of the colony count. The obtained fungi of the year were mainly centralized in the stage D of the sampler (2.0–3.0 μm), accounting for 37.8% of the colonies. The minimum value occurred at stage F (<0.65 μm), accounting for 1.10% of the colonies.     

Exposure to airborne microorganisms,hyphal fragments,and pollen in a field of organically grown strawberries

Many working environments are predisposed for larger than average amounts of fungi and other microorganisms often due to organic material being handled. From 2003 to 2007, the area used for strawberry production in Denmark increased by 62%. The purpose of this study was to determine the levels of exposure to microorganisms, endotoxin, (1→3)-β-d-glucan (β-glucan), and pollen in a field of strawberries. The study was carried out in eastern Denmark from the middle of June to the beginning of August 2008. The strawberries were grown organically, and microbiological pest control agents (MPCAs) were applied during this and former growth seasons. In order to measure exposure to inhalable bioaerosol components, we used stationary filter samplers. Bioaerosol sampling was performed during 4 working days, and a total of 57 samplings were performed. The filters were analysed for contents of fungi, MPCAs, endotoxin, β-glucan, and pollen. The mean exposure was 6,154 CFU Cladosporium sp. m⁻³, 1.0 × 10⁵ fungal spores m⁻³, 4.1 × 10⁴ hyphal fragments m⁻³, 5.8 × 10³ pollen m⁻³, 57.3 ng β-glucan m⁻³, and 8.9 endotoxin units (EU) m⁻³. A significant and positive correlation was found between β-glucan and fungal spores and between CFU of Cladosporium sp. and CFU of fungi. We selected specifically for Metarhizium anisopliae, Beauveria bassiana, and the applied MPCAs Trichoderma harzianum, T. polysporum, and Bacillus thuringiensis but found none of these species. In conclusion, our study shows that berry pickers in this organic strawberry field were potentially subjected to higher levels of fungal spores, Cladosporium sp., hyphal fragments, pollen, and thus also β-glucan than is usually seen in outdoor air. Exposure to MPCAs was not seen. The exposure to endotoxin was only slightly higher than e.g. in a town.     

Possible cause of allergy for the librarians: books manipulation and ventilation as sources of fungus spores spreading

The objective of this study was to investigate the airborne viable spore concentrations and identify the fungal species in all indoor spaces from the lending library at the Technical University “Gheorghe Asachi” Iaşi, Romania. Samples were collected using the settle plate method and swab samples from PC cooler fan grids as well as from the wall in it’s vicinity and from paper/wood fragments. There were no air conditioning systems in the library rooms. The heating systems were standard with an environmental temperature of 20°C in winter, except for the storage area of old/rare books stacks II, where the temperature was below 15°C and the humidity was very high due to water infiltrations in the walls and poor maintenance. More than 296 fungal colonies from over 78 samples were identified, enumerated, and reported. Indoor airborne fungal spore deposition rates were within the range of 419–1,677 CFU/m², with the predominance of genera being Aspergillus spp., Penicillium spp., Cladosporium spp., Alternaria spp. and Chaetomium spp. Approximately ten fungal colonies could not be identified. The PC fans move particles from the low levels (floor) to the air, and are thus responsible for maintaining a constant air velocity and contribute to fungal-spore aerosolization, transport, deposition and resuspension. Book paper and wood furniture are known to be suitable substrates for cellulose degrading fungi.     

Indoor and outdoor atmospheric fungal spores in the São Paulo metropolitan area (Brazil): species and numeric concentrations

The aim of this study was to estimate the indoor and outdoor concentrations of fungal spores in the Metropolitan Area of Sao Paulo (MASP), collected at different sites in winter/spring and summer seasons. The techniques adopted included cultivation (samples collected with impactors) and microscopic enumeration (samples collected with impingers). The overall results showed total concentrations of fungal spores as high as 36,000 per cubic meter, with a large proportion of non culturable spores (around 91% of the total). Penicillium sp. and Aspergillus sp. were the dominant species both indoors and outdoors, in all seasons tested, occurring in more than 30% of homes at very high concentrations of culturable airborne fungi [colony forming units(CFU) m⁻³]. There was no significant difference between indoor and outdoor concentrations. The total fungal spore concentration found in winter was 19% higher than that in summer. Heat and humidity were the main factors affecting fungal growth; however, a non-linear response to these factors was found. Thus, temperatures below 16°C and above 25°C caused a reduction in the concentration (CFU m⁻³) of airborne fungi, which fits with MASP climatalogy. The same pattern was observed for humidity, although not as clearly as with temperature given the usual high relative humidity (above 70%) in the study area. These results are relevant for public health interventions that aim to reduce respiratory morbidity among susceptible populations.     

Prevalence of airborne Aspergillus flavus in Khartoum (Sudan) Airspora with reference to dusty weather and inoculum survival in simulated summer conditions

Khartoum air was scanned for airborne Aspergillus flavus for 12 months using the horizontal gravitational settling method. Frequency of occurrence was related to total fungal catch and dusty weather. The Aspergilli were prevalent (68% of total isolated/plate/month) and A. flavus constituted 31% of the total Aspergilli. In June (hot, dry & dusty) Aspergilli constituted 79% of the total isolates, whilst A. flavus represented 30% from amongst the other Aspergilli. A. flavus, A. niger, A. nidulans (conidial & ascosporic states), A. terreus, Eurotium amstelodami and A. fumigatus, in descending order of prevalence were isolated in June. Other pathogenic or potentially pathogenic forms, isolated, were Cladosporium, Curvularia and Penicillium. Amongst winter isolations A. flavus was sporadic to absent in occurrence. A. flavus spore inocula that underwent hourly intermitted exposure to 45 °C, showed a decrease in spore germinability as well as reduced germ length.     

Reduction of phenolics content and COD in olive oil mill wastewaters by indigenous yeasts and fungi

Olive oil mill wastewaters (OOMW) cause a recurrent environmental pollution problem. The large concentration of phenolic compounds in the organic fraction of OOMW is principally responsible for the phytotoxicity and microbial growth inhibitory effects of the effluent. Candida boidinii, Geotrichum candidum, a Penicillium sp. and Aspergillus niger HA37 were isolated from OOMW. When cultivated directly on an undiluted OOMW-based medium containing 82 g l⁻¹ COD, these strains removed only 4–8% of chemical oxygen demand (COD) and phenolics. In contrast, reduction values attaining respectively 40–73% for phenolics and 45–78% for COD removal in the undiluted OOMW-based medium were obtained when using the strains gradually acclimated to high concentration of OOMW by successive stepwise transfer from media containing COD of 20.5 up to 82 g l⁻¹. Possibly, a sufficient production level of degradation and/or detoxification enzymes has to be attained to overcome the toxic effects of the phenolic fraction of concentrated OOMW. The present investigation calls attention to the necessity of acclimation for certain fungal and yeasts strains potentially useful for treating highly polluted effluents.