Cryptococcus gattii oder Cryptococcus neoformans var. gattii ist ein infektiöser Hefepilz, der vornehmlich in tropischen und subtropischen Klimaten vorkommt. Er ist ein Erreger der Kryptokokkose, einer opportunistischen Infektion. Während eine durch Cryptococcus neoformans verursachte Kryptokokkose fast ausschließlich bei Patienten mit massiver Immunschwäche auftritt, vermag Cryptococcus gattii auch bei Menschen mit einem intakten Immunsystem die Erkrankung auszulösen.
Im Jahr 1999 wurde er erstmals auf der west-kanadischen Insel Vancouver Island nachgewiesen. Zwischen 1999 und 2003 soll er sich an der Pazifikküste von Vancouver Island auf dem Festland in der Provinz British Columbia verbreitet haben. Ab dem Jahr 2005 wurde eine mutierte Variante, VGIIc, in den nordwestlichen US-Bundesstaaten Washington, Idaho und Oregon nachgewiesen. Im Nordwesten der USA wurde eine Variante mit erhöhter Letalität beobachtet.[1] In Süd-Kalifornien wurde bei mehreren Patienten die Variante VGIII nachgewiesen.
Der Pilz ist für immunschwache Patienten schon immer gefährlich gewesen: Die Letalitätsrate wird auch bei einer adäquaten antifungalen Therapie auf 10 bis 25 Prozent geschätzt.[2] Die im Jahr 2010 neue Variante ist noch virulenter und kann auch gesunde Menschen sowie domestizierte Tiere über die Atemwege angreifen, wobei von infizierten Bäumen – Wirtspflanzen sind üblicherweise Eucalyptus camaldulensis und andere Eukalyptus-Spezies – stammende Sporen inhaliert werden.[3][4] Die Kryptokokkose genannte Krankheit ist schwer zu diagnostizieren, lässt sich aber durch Antimykotika als Tabletten und Infusionen behandeln. Zu den Symptomen gehören wochenlanger Husten, Schmerzen in der Brust, Kurzatmigkeit, Fieberanfälle, Gewichtsverlust, Schweißausbrüche und Kopfschmerzen.[5]
Cryptococcus gattii befällt auch Haustiere wie Hunde, Katzen und Schafe, die unter Schleimbildung in der Nase sowie Atem- und Nervenschmerzen mit Beeinträchtigung der Lymphknoten leiden.
Möglicherweise durch Abholzung und Bauarbeiten gelangten die Sporen in den Pazifik, wo sie eine Bedrohung für Delfine und Seelöwen darstellen. Der erste Delfin in der Salish Sea (zwischen Vancouver Island und dem US-Bundesstaat Washington) könnte bereits 1997 dem Pilz zum Opfer gefallen sein.[6]
Cryptococcus gattii oder Cryptococcus neoformans var. gattii ist ein infektiöser Hefepilz, der vornehmlich in tropischen und subtropischen Klimaten vorkommt. Er ist ein Erreger der Kryptokokkose, einer opportunistischen Infektion. Während eine durch Cryptococcus neoformans verursachte Kryptokokkose fast ausschließlich bei Patienten mit massiver Immunschwäche auftritt, vermag Cryptococcus gattii auch bei Menschen mit einem intakten Immunsystem die Erkrankung auszulösen.
Cryptococcus gattii, formerly known as Cryptococcus neoformans var. gattii, is an encapsulated yeast found primarily in tropical and subtropical climates. Its teleomorph is Filobasidiella bacillispora, a filamentous fungus belonging to the class Tremellomycetes.
Cryptococcus gattii causes the human diseases of pulmonary cryptococcosis (lung infection), basal meningitis, and cerebral cryptococcomas. Occasionally, the fungus is associated with skin, soft tissue, lymph node, bone, and joint infections. In recent years, it has appeared in British Columbia, Canada and the Pacific Northwest.[1] It has been suggested[2][3] that global warming may have been a factor in its emergence in British Columbia. It has also been suggested that tsunamis, such as the 1964 Alaska earthquake and tsunami, might have been responsible for carrying the fungus to North America and its subsequent spread there.[4] From 1999 through to early 2008, 216 people in British Columbia have been infected with C. gattii, and eight died from complications related to it.[5] The fungus also infects animals, such as dogs, koalas, and dolphins.[3] In 2007, the fungus appeared for the first time in the United States, in Whatcom County, Washington[6] and in April 2010 had spread to Oregon.[7] The most recently identified strain, designated VGIIc, is particularly virulent, having proved fatal in 19 of 218 known cases.[8]
Cryptococcus gattii has recently been divided into five species.[9] These are C. gattii, C. bacillisporus, C. deuterogattii, C. tetragattii, and C. decagattii.
Cryptococcal disease is an uncommon disease that can affect the lungs (pneumonia) and nervous system (causing meningitis and focal brain lesions called cryptococcomas) in humans. The main complication of lung infection is respiratory failure. Central nervous system infection may lead to hydrocephalus, seizures, and focal neurological deficit.
Soil debris associated with certain tree species has been found frequently to contain C. gattii VGIII MATα and MATa, and less commonly VGI MATα, in Southern California. These isolates were fertile, were found to be indistinguishable from the human isolates by genome sequence, and were virulent in in vitro and animal tests. Isolates were found associated with Canary Island pine (Pinus canariensis), American sweetgum (Liquidambar styraciflua), and Pohutukawa tree (Metrosideros excelsa).[10] [11][12]
One study concluded "[j]ust as people who travel to South America are told to be careful about drinking the water, people who visit other areas like California, the Pacific Northwest, and Oregon need to be aware that they are at risk for developing a fungal infection, especially if their immune system is compromised."[13]
The highest incidences of C. gattii infections occur in Papua New Guinea and Northern Australia. Though cases have been reported in various other regions including Brazil, India and the Pacific Northwest of North America.
Unlike Cryptococcus neoformans, C. gattii is not particularly associated with human immunodeficiency virus infection or other forms of immunosuppression. The fungus can cause disease in healthy people, potentially due to its ability to grow extremely rapidly within white blood cells.[14]
In the United States, C. gattii serotype B, subtype VGIIa, is largely responsible for clinical cases. The VGIIa subtype was responsible for the outbreaks in Canada; it then appeared in the U.S. Pacific Northwest.
According to a CDC summary, from 2004 to 2010, 60 cases were identified in the U.S.: 43 in Oregon, 15 from Washington, and one each from Idaho and California. Slightly more than half of these case were immunocompromised; 92% of all isolates were of the VGIIa subtype. In 2007, the first case in North Carolina was reported, subtype VGI, which is identical to the isolates found in Australia and California.
The multiple clonal clusters in the Pacific Northwest likely arose independently of each other as a result of sexual reproduction occurring within the highly sexual VGII population.[15] VGII C. gattii have probably undergone either bisexual or unisexual reproduction in multiple different locales, thus giving rise to novel virulent phenotypes.
The infection is caused by inhaling yeasts or spores. The fungus is not transmitted from person to person or from animal to person. A person with cryptococcal disease is not contagious.[16]
Most people who are exposed to the fungus do not become ill. In people who become ill, symptoms appear many weeks to months after exposure. Symptoms of cryptococcal disease include:
Culture of sputum, bronchoalveolar lavage, lung biopsy, cerebrospinal fluid or brain biopsy specimens on selective agar allows differentiation between the five members of the C. gattii species complex and the two members of the C. neoformans species complex.
Molecular techniques may be used to speciate Cryptococcus from specimens that fail to culture.
Cryptococcal antigen testing from serum or cerebrospinal fluid is a useful preliminary test for cryptococcal infection, and has high sensitivity for disease. It does not distinguish between different species of Cryptococcus.
Medical treatment consists of prolonged intravenous therapy (for 6–8 weeks or longer) with the antifungal drug amphotericin B, either in its conventional or lipid formulation. The addition of oral or intravenous flucytosine improves response rates. Oral fluconazole is then administered for six months or more.
Antifungals alone are often insufficient to cure C. gattii infections, and surgery to resect infected lung (lobectomy) or brain is often required. Ventricular shunts and Ommaya reservoirs are sometimes employed in the treatment of central nervous system infection.
People who have C. gattii infection need to take prescription antifungal medication for at least 6 months; usually the type of treatment depends on the severity of the infection and the parts of the body that are affected.
Cryptococcus gattii, formerly known as Cryptococcus neoformans var. gattii, is an encapsulated yeast found primarily in tropical and subtropical climates. Its teleomorph is Filobasidiella bacillispora, a filamentous fungus belonging to the class Tremellomycetes.
Cryptococcus gattii causes the human diseases of pulmonary cryptococcosis (lung infection), basal meningitis, and cerebral cryptococcomas. Occasionally, the fungus is associated with skin, soft tissue, lymph node, bone, and joint infections. In recent years, it has appeared in British Columbia, Canada and the Pacific Northwest. It has been suggested that global warming may have been a factor in its emergence in British Columbia. It has also been suggested that tsunamis, such as the 1964 Alaska earthquake and tsunami, might have been responsible for carrying the fungus to North America and its subsequent spread there. From 1999 through to early 2008, 216 people in British Columbia have been infected with C. gattii, and eight died from complications related to it. The fungus also infects animals, such as dogs, koalas, and dolphins. In 2007, the fungus appeared for the first time in the United States, in Whatcom County, Washington and in April 2010 had spread to Oregon. The most recently identified strain, designated VGIIc, is particularly virulent, having proved fatal in 19 of 218 known cases.
Cryptococcus gattii es una levadura encapsulada que se encuentra principalmente en climas tropicales y subtropicales. Su teleomorfo es Filobasidiella bacillispora, un hongo filamentoso que pertenece a la clase Tremellomycetes.
Cryptococcus gattii causa, en seres humanos, una enfermedad pulmonar, la criptococosis (infección pulmonar), meningitis basal, y cryptococcomas cerebral. Ocasionalmente, el hongo está asociado con infecciones de la piel, tejidos blandos, nódulos linfáticos, huesos, y articulaciones. En años recientes, ha aparecido en Columbia Británica, Canadá.[1] Desde 1999 hasta comienzos de 2008, doscientas dieciséis personas se han infectado en Columbia Británica con C. Gatti, y ocho murieron de complicaciones derivadas de esto.[2] El hongo además infecta animales como perros, koalas y delfines.[3] En 2007, el hongo apareció por primera vez en los Estados Unidos, en el Condado de Whatcom, Washington[4] y en abril de 2010 ha pasado a Oregón.[5] La cepa más recientemente identificada, designada VGIIc, es particularmente virulenta, habiendo causado la muerte de 5 de 21 casos humanos identificados.[6]
C. gattii previamente ha tendido diferentes nombres incluyendo
La enfermedad Cryptocóccica es muy rara y puede afectar los pulmones (pneumonia) y sistema nervioso (causando meningitis y lesiones cerebrales focales llamadas criptococcomas) en humanos. La principal complicación de la infección pulmonar es la insuficiencia respiratoria . La infección del sistema nervioso central puede conducir a hidrocefalia, convulsiones y déficit neurológico focal.
Las más altas incidencias de infecciones por C. gattii se dan en Papua Nueva Guinea y Australia septentrional. Se han reportado también casos en India, Brasil, la isla de Vancouver, Canadá, estado de Washington, y Oregón.
A diferencia de Cryptococcus neoformans, C. gattii no está asociado particularmente con el virus de inmunodeficiencia adquirida u otras formas de inmunosupresión. El hongo puede causar la enfermedad en personas sanas.
La infección se produce al inhalar esporas. El hongo no se trasmite de persona a persona o desde animal a persona. Una persona con enfermedad criptocóccica no es contagiosa.
La mayoría de las personas expuestas al hongo no llegan a enfermarse. En aquellos que se enferman, los síntomas pueden llegar a aparecer muchas semanas o meses después de la exposición . Los síntomas son:
Cultivo de esputo, lavado broncoalveolar, biopsia de pulmón, fluido cerebrospinal o biopsia de cerebro, los especímenes en agar selectivo permite diferenciaión entre C. gattii y C. neoformans.
Se pueden usar técnicas moleculares especializadas para Cryptococcus de especímenes que fallan en cultivo.
La prueba de antígeno de Suero y CSF criptocócccica es una prueba preliminar útil para la infección criptococcica, y tiene una alta sensibilidad para detectar la enfermedad. No distingue entre diferentes especies de Cryptococcus.
El tratamiento médico consiste de prolongada terapia intravenosa (durante 6–8 semanas o más) con una droga antifúngica Anfotericina B, o en su formulación convencional o lipídica. La adición de terapia intravenosa u oral de flucitosina mejora la tasa de respuesta. Fluconazol oral se administra entonces por seis a ocho meses o más.
Los antifúngicos solos son, a menudo, insuficientes para la cura de las infecciones por C. gattii , y la cirugía para resecar pulmones infectados (lobectomía) o cerebro es a menudo requerido. shunts ventriculares y depósitos de Ommaya se emplean algunas veces en el tratamiento de las infecciones del sistema nervioso central.
Cryptococcus gattii es una levadura encapsulada que se encuentra principalmente en climas tropicales y subtropicales. Su teleomorfo es Filobasidiella bacillispora, un hongo filamentoso que pertenece a la clase Tremellomycetes.
Cryptococcus gattii causa, en seres humanos, una enfermedad pulmonar, la criptococosis (infección pulmonar), meningitis basal, y cryptococcomas cerebral. Ocasionalmente, el hongo está asociado con infecciones de la piel, tejidos blandos, nódulos linfáticos, huesos, y articulaciones. En años recientes, ha aparecido en Columbia Británica, Canadá. Desde 1999 hasta comienzos de 2008, doscientas dieciséis personas se han infectado en Columbia Británica con C. Gatti, y ocho murieron de complicaciones derivadas de esto. El hongo además infecta animales como perros, koalas y delfines. En 2007, el hongo apareció por primera vez en los Estados Unidos, en el Condado de Whatcom, Washington y en abril de 2010 ha pasado a Oregón. La cepa más recientemente identificada, designada VGIIc, es particularmente virulenta, habiendo causado la muerte de 5 de 21 casos humanos identificados.
Cryptococcus gattii (Vanbreus. & Takashio) Kwon-Chung & Boekhout, anteriormente conhecido por Cryptococcus neoformans var gattii, é uma levedura encapsulada que ocorre primariamente em regiões de clima tropical e subtropical. O seu teleomorfo é designado por Filobasidiella bacillispora, um fungo filamentoso pertencente à classe Tremellomycetes. A espécie é uma das causas de criptococose em humanos, uma infecção pulmonar frequentemente fatal. Também é considerada o agente etiológico de algumas formas de meningite basal e da afecção cerebral conhecida por criptococoma.[1]
Cryptococcus gattii (Vanbreus. & Takashio) Kwon-Chung & Boekhout, anteriormente conhecido por Cryptococcus neoformans var gattii, é uma levedura encapsulada que ocorre primariamente em regiões de clima tropical e subtropical. O seu teleomorfo é designado por Filobasidiella bacillispora, um fungo filamentoso pertencente à classe Tremellomycetes. A espécie é uma das causas de criptococose em humanos, uma infecção pulmonar frequentemente fatal. Também é considerada o agente etiológico de algumas formas de meningite basal e da afecção cerebral conhecida por criptococoma.
