MICROBIAL GLOSSARY    

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 Memnoniella sp.

Memnoniella sp. Cellulolytic fungus very closely related to Stachybotrys. Both fungi have a worldwide distribution and often found together, and commonly found in soil. Recent studies on mycotoxins revealed that Memnoniella echinata can have toxicity similar to that of some isolates of S. chartarum. In terms of their chemical products, both S. chartarum and M echinata produce phenylspirodrimanes, but these two organisms differ in that the former produces macrocyclic and trichoverroid trichothecenes and the latter produces griseofulvins. Both produce varying amounts of simple trichothecenes. Thus, it is suggested that Memnoniella should also be considered potentially dangerous in indoor air. The conidiophores are dark, simple, bearing at apex a cluster of thick, short phialides; conidia of Memnoniella echinata are very similar to those of Stachybotrys, dark, 1-celled, globose. The major difference between the two fungi is that the conidia are in long persistent chains (aggregated in slimy heads in Stachybotrys). Also the aerodynamic diameter of Memnoniella is smaller and it would be expected to have an even greater potential to penetrate deep into lungs than the conidia of Stachybotrys. Cultivation - Corn meal agar, 24°C. 

Monilia sp.

Monilia sp. Its mycelium is white or gray, and abundant in culture. Conidiophore branched; conidia pink, gray, or tan in mass, 1-celled, short cylindric to rounded, in acropetalous chains. Cultivation - Potato dextrose agar, 24°C.

 Mucor sp.

Mucor sp. Often found in soils, dead plant material (hay), horse dung, fruits and fruit juice. It is also found in leather, meat, dairy products, animal hair, and jute. It is almost always in house dust, frequently in air samples and old dirty carpets. Wood chips and sawdust are often attacked by M. plimbeus causing "wood chips disease" and "furrier’s lung". Accumulated dust in ventilation ducts may contain high concentrations of viable Mucor spores. Asthmatic reactions to Mucor have been described. It is a Zygomecete fungus that may be allergenic (skin and bronchial tests). It is an opportunistic pathogenic organism and it may cause mucorosis in immune compromised individuals. The sites of infections are the lung, nasal sinus, brain, eye, and skin. Infection may have multiple sites. This organism and other Zygomycetes will grow rapidly on most fungal media. Conidia (aplanospores) are globose to ellipsoidal,7-8 microns in diameter, yellowish brown and slightly rough-walled, and are produced in sporangia that are developed around a piriform columella with typical projections. Identification is based on the way sporangia are formed. Cultivation - Potato dextrose agar, 24°C.

Mycotoxin - a toxin produced by a fungus

 Myxomycetes

Ubiquitous, type I allergen. Often found on decaying plant material, however occasionally found indoors. Dispersed by wind in the dry phase, while the wet amoebic phase is motile. Myxomycetes exhibit characteristics of protozoans and fungi. Indistinguishable from smuts under 600x microscopy.

 Nigrospora sp.

Nigrospora sp. Nigrospora is reported to be allergenic. Morphological characteristics include shiny black conidia, 1-celled, egg-shaped to flattened-spherical, produced singly, and often have an equatorial colorless line or germ slit. Nigrospora often appears as white wooly colonies growing fairly rapidly. This fungus can be a plant parasite or saprophytic.

 Paecilomyces sp.

Paecilomyces sp. - Commonly found in soil and dust, less frequently in air. P. variotii can cause paecilomycosis. Linked to wood-trimmers disease and humidifier associated illnesses. Some members of this genus are reported to cause pneumonia. It has also been reported as causative agent of allergic alveolitis. It may produce arsine gas if growing on arsenic substrate, this can occur on wallpapers covered with Paris green. Cultivation - Potato dextrose agar, 24°C.

Penicillium sp.

Penicillium sp. - (Aw 0.78). A wide number of organisms belong to this genus. Identification to species is difficult. Often found in aerosol samples. Commonly found in soil, food, cellulose, paint, grains, and compost piles. It is commonly found in carpet, wallpaper, and in interior fiberglass duct insulation. Although this fungus is less allergy-provoking than the other molds, Penicillium is reported to be allergenic (skin) and it may cause hypersensitivity pneumonitis and allergic alveolitis in susceptible individuals. It can cause other infections such as keratitis, penicilliosis, and otomycosis. Some species can produce mycotoxins including 1). Ochratoxin which is damaging to the kidneys and liver and is also a suspected carcinogen; there is also evidence that impairs the immune system. 2). Citrinin that can cause renal damage, vasodilatation, and bronchial constriction. 3). Gliotoxin which is an immunosuppressive toxin, and 4). Patulin that is believed to cause hemorrhaging in the brain and lungs and is usually associated with apple and grape spoilage. It can also cause extrinsic asthma. P. camemberti has been responsible for inducing occupational allergies among those who work with soft white cheeses on which the fungus grows. P. chrysogenum has been found on building materials, including paints, chip boards, and wallpaper. Cultivation - Potato dextrose agar or Malt extract agar, 24°C.

Penicillium brevicompactum

Penicillium brevicompactum Commonly found in water damaged carpet, wallpaper, and some types of insulation. Penicillium is reported to be allergenic (skin) and it may cause hypersensitivity pneumonitis and allergic alveolitis in susceptible individuals. It can cause other infections such as keratitis, penicilliosis, and otomycosis. Penicillium brevicompactum can produce the mycotoxin mycophenolic acid.

 Penicillium chrysogenum

Penicillium chrysogenum This species, formerly known as Penicillium notatum, was one of the first known producers of penicillin. It is commonly found and can act as a food source for some types of dust mites. Penicillium chrysogenum is often found growing as a dark green colony and can produce the mycotoxins roquefortine C, chrysogine, and meleagrin.

 Phoma sp.

Phoma sp. This fungus is reported to be a common indoor air allergen and it is also commonly found on various plant parts and soil. Phoma species are reported to grow extensively on painted walls, particularly in humid places such as showers. Some species can be pathogenic to humans, causing either systematic or subcutaneous diseases (phaeohyphomycosis). Morphological characteristics of this fungus include the production of dark colonies resulting from microscopic dark fruiting structures called pycnidia which harbor one-celled spores. It has been reported to produce pink or purple spots on painted walls and grow on paint, cement, and rubber. Cultivation - Potato dextrose agar or Malt extract agar, 24°C.

 Pithomyces sp.

Pithomyces sp. This fungus is found mainly growing on decaying plants, specially grasses. It produces a mycotoxin called sporidesmin (a piperazinedione) known to be pathogenic in animals causing facial eczema and liver damage. Spores are produced at the apex of short side branches of vegetative filaments, dark brown, 2- to several celled. The most common isolated species is P. chartarum and its spores have both longitudinal and transverse septa. Cultivation - Corn meal agar, 24°C.

 Rhinocladiella sp.

Rhinocladiella sp. Naturally found in soil and woody plant materials as a saprophyte. Reported among the principal fungi causing chromoblastomycosis, a disease characterized by a chronic localized infection of the skin and subcutaneous tissue that follows the traumatic implantation of the causal agent. The lesions are verrucoid, ulcerated, and crusted, and may be flat or raised 1-3 cm. The mycosis usually remains localized with extensive keloid formation. Forms of the disease include Verrucous dermatitis, Brain abscess syndrome, Single or multiple cysts, Local or systemic lesions. Morphological characteristics - Conidiophores simple, or branched in some species. Conidia apical on new growing points of conidiophore, subhyaline to dark, mostly 1-celled, ovoid to oblong-ellipsoid, dry. Cultivation - Potato dextrose agar or Malt extract agar, 24°C.

 Rhizomucor sp.

Rhizomucor sp. Belongs to the Zygomycetes (mucorales) and it is reported to be allergenic and often linked to occupational allergy. It may cause mucorosis in immune compromised individuals. It occupies a similar biological niche to Mucor sp.. The sites of infection are the lung, nasal sinus, brain, eye, and skin. Infection may be multiple sites. It may also cause zygomycosis (rhino-facial-cranial area, lungs, gastrointestinal tract, and skin). This disease is associated with the acidotic diabetes, malnourished children, severely burned patients, and other diseases such as leukemia and lymphoma, immunosuppressive therapy, or use of cytotoxins and corticosteroids. The fungi show a proclivity for vessel invasion resulting in embolization and necrosis of surrounding tissue. Morphological characteristics of this fungus are the production of sporangiospores, which are diminute, rounded thick walled bodies resistant to heat and drought. They are produced in large numbers in globular envelopes (sporangia) at the tip of special hyphae (sporangiophores). Identification is based on the way the sporangia are formed. Cultivation - Potato dextrose agar, 24°C.

 Rhizopus sp.

Rhizopus sp. Fungus found throughout the environment. It has been reported to be allergenic and it is often linked to occupational allergy. It may cause mucorosis in immune compromised individuals. It may also cause zygomycosis (rhino-facial-cranial area, lungs, gastrointestinal tract, and skin). This disease is associated with the acidotic diabetes, malnourished children, severely burned patients, and other diseases such as leukemia and lymphoma, immunosuppressive therapy, or use of cytotoxins and corticosteroids. The fungi show a propensity for vessel invasion resulting in embolization and necrosis of surrounding tissue. Cultivation - Potato dextrose agar, 24°C.

Scedosporium sp.

Scedosporium sp. This fungus is found in soils, decaying plants matter or dung. Listed among the principal fungi that cause Phaeohyphomycosis. This disease consists of a group of mycotic infections characterized by the presence of dematiaceous septate hyphae and sometimes yeast or combination of both. Species of Scedosporium mostly affect people with compromised immune systems, but healthy people may also become infected. The hyphae may be short to elongate, distorted or swollen, regularly shaped or any combination of the above. Infections of the eyes and skin by the black fungi could also be included in this disease. . Cultivation - Potato dextrose agar, 24°C.

 Scopulariopsis sp.

Scopulariopsis sp. This fungus is ubiquitous, and can be found on a wide variety of materials including old carpets and water-damaged wallpaper. Exposures from Scopulariopsis brevicaulis have been associated with cases of occupational allergy in the tobacco industry. It can decompose arsenic compounds found on building materials with an arsenic substrate, such as, some types of wallpaper and paints.

Sepedonium sp.

Sepedonium sp. This fungus is mainly found as parasite of mushrooms, but it is also isolated from soil. Most easily recognized by the spores, which are colorless to yellow, spiny, round, 1-celled, and produced singly at the ends of short filaments. Sometimes spores of Sepedonium can be very similar to those of the human pathogen Histoplasma capsulatum and species of Mortierella. . Cultivation - Potato dextrose agar, 24°C.

 Smuts

Ubiquitous, type I allergen. They are parasitic plant pathogens that require a living host. Most often found on corn, grass, weeds, flowering plants and other fungi; usually disseminated by wind. Indistinguishable from myxomycetes under 600x microscopy.

Sporothrix sp.

Sporothrix sp. It can cause sporotrichosis. Usually only in populations which are immune compromised. Morphological characteristics include conidiophores mostly simple, 1-celled or septate, hyaline, bearing a loose cluster of dry conidia at apex; conidia, hyaline, 1-celled, globose to ovoid, born on short, prominent denticles. Mostly found as saprophyte. Cultivation - Sabouraud’s agar, 24°C.

 Sporotrichum sp.

Sporotrichum sp. This fungus is reported to be allergenic. Sporotrichum is commonly found on decaying plant matter, wet and rotting wood and in landscaping mulch. It is morphologically similar to the human pathogen Sporothrix.

 Stachybotrys

Stachybotrys sp. - Considerable recent media attention has been focused on the fungi Stachybotrys chartum due to infant deaths in Cleveland from pulmonary hemosiderosis which may be associated with contamination of residences with this fungi. Stachybotrys thrives on water damaged cellulose rich materials such as sheet rock, paper, ceiling tiles, cellulose containing insulation backing and wallpaper. The presence of this fungus in buildings is significant because of the mold’s ability to produce mycotoxins, which are extremely toxic, such as Satratoxin H. Exposure to these toxins can occur through inhalation, ingestion or dermal exposure. Symptoms include dermatitis, cough, rhinitis, nose bleeds, a burning sensation in the mouth and nasal passage, cold and flu symptoms, headache, general malaise, and fever. Inhalation of conidia may also induce pathological changes (pneumomycotoxicoses). Satratoxin H has been reported to be abortogenic in animals and in high doses or chronic low doses it can be lethal. S. chartarum produces other macrocyclic and trichoverroid trichothecenes and, like Memnoniella echinata, produces phenylspirodrimanes, which are immunosuppressive. Stachybotrys typically appears as a sooty black fungus occasionally accompanied by a thick mass of white mycelia. As a general rule, air sampling for Stachybotrys yields unpredictable results mainly due to the fact that this fungus is usually accompanied by other fungi such as Aspergillus and Penicillium that normally are better aerosolized than Stachybotrys. Bulk or surface sampling of suspect materials can be analyzed in a laboratory for identification by light microscopy. Cultivation - Corn meal agar, 24°C.

 Stemphylium sp.

Stemphylium sp. - Reported to be allergenic. Isolated from dead plants and cellulose materials; it can be parasitic or saprophytic. Morphological characteristics - Dark conidia, with cross and longitudinal septa, variable in shape, frequently globose, broadly ellipsoid, or ovoid, often constricted at major septum. Cultivation - Potato dextrose agar or V-8 juice agar, 24°C.

 Syncephalastrum sp.

Syncephalastrum sp. This organism is considered to be primarily non pathogenic in humans and is usually found in soils and in dung. Morphologically it is distinct with conidiophores erect, branched, tips enlarged, bearing a head of rod shaped sporangioles, each producing a row of nearly spherical conidia.

 Torula sp.

Torula sp. Reported to be allergenic. Found as a saprophyte. Morphological characteristics - Conidiophores short, dark, simple, branched or absent; conidia 1-to several-celled, round, dark, and in chains. Cultivation - Potato dextrose agar, 24°C. 

Trichoderma sp.

Trichoderma sp. Trichoderma is most commonly found in soil. Trichoderma is often found in litter materials (polluted streams, sewage plants and driftwood). It is found on paper, and in kitchens on many common tableware materials. T. viridae is often isolated from indoor air samples and house dust. Materials such as wood construction and mineral fiber panels can be very affected by this fungus. Trichoderma sp. is reported to be allergenic but are relatively rare. Inhalation of the conidia or teh volatile organic compounds, may cause symptoms similar to those of Stachybotrys reactions. Cultivation - Potato dextrose agar, 24°C.

Tricothecium sp.

Tricothecium sp. Occurring in soil and decaying plant matter, often found as an epiparasite on black knot of plum. Spores are 2-celled, colorless to pink, bilaterally symmetrical and are produced in long chains from the unbranched conidiophores. Cultivation - Potato dextrose agar, 24°C. Produces mycotoxins, trichothecin and other trichothecenes.

 Ulocladium sp.

Ulocladium sp. - (Aw 0.89). This fungus is reported to be allergenic and considered cosmopolitan. It is commonly found as a saprophyte on plant materials and soils. Some species can be also found on dead herbaceous plants, rotten woods, paper, textiles, and other organic substrates (cellulose,)such as water-damaged building materials. Ulocladium is also found in dust and air samples. Ulocladium is known to be a common airway allergen. Cultivation - Potato dextrose agar, 26°C.

 Verticillium sp.

Verticillium sp. Commonly found in soil and decaying plant matter, known also to cause plant diseases. Characterized by whorls of phialides produced along the length of undifferentiated filaments of on conidiophores. Conidia are colorless, 1- or 2-celled, collected in small wet masses. Cultivation - Potato dextrose agar, 26°C.

 Yeast

Most species of yeast reproduce asexually through a process called budding. The daughter cell of the parent yeast cell is at first much smaller and tends to cling to the parent and often clumps or chains of cells are formed. Ascospores are formed during sexual reproduction of some yeasts.

 Yeasts-Candida sp.

Candida sp. Part of the normal flora and other mucous membranes in the body. Thrush and other diseases caused by this yeast usually occur after prolonged treatment with antibiotics or steroids. The environment is not a likely source of exposure for this fungus and cells from the organism are usually not airborne. Mucocutaneous candidiasis is one of the most common manifestations of HIV infection. While other yeasts may occasionally cause clinical disease, Candida albicans is the organism isolated from most patients. Most species of yeast reproduce asexually through a process called budding. The daughter cell is at first much smaller and tends to cling to the parent and often clumps or chains cell is at first much smaller and tends to cling to the parent and often clumps or chains of cells are formed. Cultivation - YM agar, 36°C

 Yeasts-Cryptococcus neofornans.

Cryptococcus neoformans Yeast considered an opportunistic pathogen, although it can cause a disease in an immune competent host. In its environmental state C. neoformans var. neoformans colonizes pigeon and other bird droppings and C. neoformans var. gatti the bark of the red gum tree. Both forms can cause disease in humans (cryptococcosis). Primary infection with C. neoformans follows exposure to an environmental source and inhalation of the fungus leading to an infection of the lung. A transient colonization of the bronchial tree may result, or more extensive pulmonary involvement may occur. Bronchial infection may be self-limiting or chronic and may lead to dissemination to other parts of the body. Meningoencephalitis is the most common manifestation of dissemination and the most severe. Symptoms depend upon the rapidity of onset of disseminated disease. The indolent cases begin with headache. Nausea, dizziness, decreased comprehension, impaired memory and gait ataxia follow and increase in severity as invasion of the cerebral cortex, brain stem, cerebellum and meninges progresses. Although pigeon excreta is considered a significant source of inoculum of this fungus, it is thought that alternative unknown routes of exposure exist. One possible source that is currently being studied is the sexual stage of C. neoformans var. neoformans, Filobasidiella neoformans var. neoformans. The basidiospores of this organism are dry, readily airborne, which may be more readily deposited in the alveoli. Sampling for C. neoformans should only be performed is a route of exposure is suspected. This would include bulk sampling of pigeon droppings in and around fresh air intakes and surface sampling of ductwork and work areas. Most species of yeast reproduce asexually through a process called budding. The daughter cell is at first much smaller and tends to cling to the parent and often clumps or chains of cells are formed. Cultivation - YM agar, 24°C.