Geotrichum | |
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Geotrichum candidum | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Saccharomycetes |
Order: | Saccharomycetales |
Family: | Dipodascaceae |
Genus: | Geotrichum Link, 1809 |
Species | |
See text |
Geotrichum is a genus of fungi found worldwide in soil, water, air, and sewage, as well as in plants, cereals, and dairy products; it is also commonly found in normal human flora and is isolated from sputum and feces. It was first described in 1809 by Johann Heinrich Friedrich Link. [1]
The genus Geotrichum includes over 100 species. Some are welcome and even considered desirable. For example, skilled cheesemakers create conditions favorable for the formation of a Geotrichum candidum rind on certain goat's milk and cow's milk cheeses, proudly declaring the rind to be the most flavorful part of such cheeses. Another example is the presence of some Geotrichum species in fermented poi.
The most clinically relevant species is Saprochaeta capitata , formerly known as Geotrichum capitatum, with most cases occurring in Europe. [2] [3]
Saprochaete clavata , formerly known as Geotrichum clavatum , is an uncommon infection that has been associated with sporadic outbreaks. [4] Geotrichum candidum is closely related to Saprochaeta sp., rarely isolated but may cause invasive and disseminated disease with high mortality yeast-like and mold-like strains have been identified. [5]
The most important risk factor for invasive fungal infection related to Geotrichum is severe immunosuppression, especially in hematological malignancies as acute leukemia, associated with profound and prolonged neutropenia. [2] [6]
Fungemia is very common, often with deep organ involvement (lung, liver, spleen, and central nervous system) and also skin and mucous membranes lesions. [7] There is no optimal treatment for Geotrichum infections but based on existing data guidelines recommend amphotericin B with or without co-administered flucytosine or with voriconazole showing good in vitro susceptibility.
Mortality associated with Geotrichum-related infections is high, ranging from 57% to 80%. [8]
Increasing the knowledge on Geotrichum related invasive fungal infections may improve early diagnosis and adequate treatment of these severe infections.
The genus Geotrichum was described by Johann Heinrich Friedrich Link in 1809 to accommodate the species G. candidum found on decaying leaves. Since then, over 130 taxa have been described in the genus, and hundreds of synonyms have been generated. [9] For example G. candidum was misclassified as the Oidium lactis in much early literature. [10] Species of Geotrichum resemble the genera Trichosporon and Protendomycopsis; however, Geotrichum is of ascomycetous affiliation whereas the latter are members of the Basidiomycota. Species of Geotrichum are occasionally mistaken for fast growing members of the genus Dipodascus , which are characterized by irregularly branched, 10–14 μm wide hyphae and the production of single-spored asci. However, unlike Geotrichum, members of the genus Dipodascus lack dichotomous branching of the peripheral hyphae and their growth rates are generally less than 3 mm per day. [11]
Species in this genus include the following: [12]
Cryptococcus neoformans is an encapsulated yeast belonging to the class Tremellomycetes and an obligate aerobe that can live in both plants and animals. Its teleomorph is a filamentous fungus, formerly referred to Filobasidiella neoformans. In its yeast state, it is often found in bird excrement. Cryptococcus neoformans can cause disease in apparently immunocompetent, as well as immunocompromised, hosts.
Candida is a genus of yeasts. It is the most common cause of fungal infections worldwide and the largest genus of medically important yeast.
Malassezia is a genus of fungi. It is the sole genus in family Malasseziaceae, which is the only family in order Malasseziales, itself the single member of class Malasseziomycetes. Malassezia species are naturally found on the skin surfaces of many animals, including humans. In occasional opportunistic infections, some species can cause hypopigmentation or hyperpigmentation on the trunk and other locations in humans. Allergy tests for these fungi are available. It is believed French revolutionary Jean-Paul Marat suffered from a fungal infection from Malassezia restricta, which lead to his frequent bathing in a medicinal substance.
Bartonellosis is an infectious disease produced by bacteria of the genus Bartonella. Bartonella species cause diseases such as Carrión's disease, trench fever, cat-scratch disease, bacillary angiomatosis, peliosis hepatis, chronic bacteremia, endocarditis, chronic lymphadenopathy, and neurological disorders.
Pichia kudriavzevii is a budding yeast involved in chocolate production. P. kudriavzevii is an emerging fungal nosocomial pathogen primarily found in the immunocompromised and those with hematological malignancies. It has natural resistance to fluconazole, a standard antifungal agent. It is most often found in patients who have had prior fluconazole exposure, sparking debate and conflicting evidence as to whether fluconazole should be used prophylactically. Mortality due to P. kudriavzevii fungemia is much higher than the more common C. albicans. Other Candida species that also fit this profile are C. parapsilosis, C. glabrata, C. tropicalis, C. guillermondii and C. rugosa.
Pneumocystis jirovecii is a yeast-like fungus of the genus Pneumocystis. The causative organism of Pneumocystis pneumonia, it is an important human pathogen, particularly among immunocompromised hosts. Prior to its discovery as a human-specific pathogen, P. jirovecii was known as P. carinii.
Sporothrix schenckii, a fungus that can be found worldwide in the environment, is named for medical student Benjamin Schenck, who in 1896 was the first to isolate it from a human specimen. The species is present in soil as well as in and on living and decomposing plant material such as peat moss. It can infect humans as well as animals and is the causative agent of sporotrichosis, commonly known as "rose handler's disease." The most common route of infection is the introduction of spores to the body through a cut or puncture wound in the skin. Infection commonly occurs in otherwise healthy individuals but is rarely life-threatening and can be treated with antifungals. In the environment it is found growing as filamentous hyphae. In host tissue it is found as a yeast. The transition between the hyphal and yeast forms is temperature dependent making S. schenckii a thermally dimorphic fungus.
A rickettsiosis is a disease caused by intracellular bacteria.
Geotrichum candidum is a fungus which is a member of the human microbiome, notably associated with skin, sputum, and faeces where it occurs in 25–30% of specimens. It is common in soil and has been isolated from soil collected around the world, in all continents.
Blastocystosis refers to a medical condition caused by infection with Blastocystis. Blastocystis is a protozoal, single-celled parasite that inhabits the gastrointestinal tracts of humans and other animals. Many different types of Blastocystis exist, and they can infect humans, farm animals, birds, rodents, amphibians, reptiles, fish, and even cockroaches. Blastocystosis has been found to be a possible risk factor for development of irritable bowel syndrome.
Geotrichosis is a mycosis caused by Geotrichum candidum.
Rhizomucor pusillus is a species of Rhizomucor. It can cause disease in humans. R. pusillus is a grey mycelium fungi most commonly found in compost piles. Yellow-brown spores grow on a stalk to reproduce more fungal cells.
Trichosporonosis is a systemic disease associated with fungi in the genus Trichosporon.
Phaeoacremonium is a fungus genus associated with wilt and decline diseases of woody hosts and human infections.
Proteus penneri is a Gram-negative, facultatively anaerobic, rod-shaped bacterium. It is an invasive pathogen and a cause of nosocomial infections of the urinary tract or open wounds. Pathogens have been isolated mainly from the urine of patients with abnormalities in the urinary tract, and from stool. P. penneri strains are naturally resistant to numerous antibiotics, including penicillin G, amoxicillin, cephalosporins, oxacillin, and most macrolides, but are naturally sensitive to aminoglycosides, carbapenems, aztreonam, quinolones, sulphamethoxazole, and co-trimoxazole. Isolates of P. penneri have been found to be multiple drug-resistant (MDR) with resistance to six to eight drugs. β-lactamase production has also been identified in some isolates.
Myceliophthora thermophila is an ascomycete fungus that grows optimally at 45–50 °C (113–122 °F). It efficiently degrades cellulose and is of interest in the production of biofuels. The genome has recently been sequenced, revealing the full range of enzymes used by this organism for the degradation of plant cell wall material.
Legionella anisa is a Gram-negative bacterium, one of more than 40 species in the family Legionellaceae. After Legionella pneumophila, this species has been isolated most frequently from water samples. This species is also one of the several pathogenic forms of Legionella having been associated with rare clinical cases of illness including Pontiac fever and Legionnaires' disease.
Methylorubrum zatmanii is a bacterium.
Streptococcus tigurinus is a novel member of the genus Streptococcus that was first discovered in 2012 by Swedish researchers.
Arthrographis kalrae is an ascomycetous fungus responsible for human nail infections described in 1938 by Cochet as A. langeronii. A. kalrae is considered a weak pathogen of animals including human restricted to the outermost keratinized layers of tissue. Infections caused by this species are normally responsive to commonly used antifungal drugs with only very rare exceptions.
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