Tue . 19 Oct 2019
TR | RU | UK | KK | BE |

Pseudallescheria boydii

pseudallescheria boydii, pseudallescheria boydii infection
Pseudallescheria boydii is a species of fungus classified in the Ascomycota It is associated with some forms of eumycetoma, maduromycosis and pseudallescheriasis Typically found in stagnant and polluted water, it has been implicated in the infection of immunocompromised and near-drowned pneumonia patients Its asexual anamorphic form is Scedosporium apiospermum Treatment of infections with P boydii is complicated by its resistance to many of the standard antifungal agents normally used to treat infections by filamentous fungi

Pseudallescheria boydii fungal infection killed three athletes injured in the 1997 Maccabiah Games when, at the opening ceremony, a bridge collapsed into the Yarkon River


  • 1 Taxonomy
  • 2 Ecology
  • 3 Growth and morphology
  • 4 Pathogenicity
  • 5 Diagnosis
  • 6 Treatment
  • 7 Epidemiology
  • 8 References


The fungus was originally described by American mycologist Cornelius Lott Shear in 1922 as a species of Allescheria Shear obtained cultures from a patient of the Medical Department of the University of Texas The microbe was apparently associated with a penetrating thorn the patient had incurred in his ankle while running barefoot 12 years before The diseased area was found to contain hyphae-containing granules that, when cultured, led to the growth of the organism Shear considered the fungus most closely related to Eurotiopsis gayoni now called Allescheria gayoni The specific epithet boydii refers to Dr Mark F Boyd, who sent Lott the specimen David Malloch moved the species to the newly created genus Petriellidium in 1970 The species was transferred to the genus Pseudallescheria in 1982 when examination of the type specimens of Petriellidium and Pseudallescheria revealed that they were the same genus


An ability to tolerate minimal aeration and high osmotic pressure enables P boydii to grow on soil, polluted and stagnant water and manure Although this fungus is commonly found in temperate climates, it is thermotolerant and can survive in tropical climates and in environments with low oxygen pressure Growth of P boydii can be seen in environments where nitrogen-containing compounds are common, usually due to human pollution Its ability to use natural gas and other aromatic compounds suggest a capacity for bioremediation

Growth and morphology

Pseudallescheria boydii is a saprotrophic fungus with broad hyphae growing up to 2–5 µm in width Colonies change in colour from white to pale brown and develop a cottony texture with maturity After a 2–3 week incubation period, cleistothecia may form containing asci filled with eight fusiform, one-celled ascospores measuring 12–18 × 9–13 µm in diameter This fungus grows on most standard media, maturing in 7 days Its primary nutrients are the sugars xylose, arabinose, glucose, sucrose, ribitol, xylitol and L-arabinitol It cannot assimilate maltose or lactose; however, it is able to assimilate urea, asparagine, potassium nitrate and ammonium nitrate The optimal temperature for growth is 25 °C 77 °F and the fungus is generally considered to be mesophilic, although it can grow at higher temperatures up to 37 °C 99 °F as well Asexual reproduction manifests in one of two forms: the Scedosporium type the most common type and the Graphium type Scedosporium apiospermum forms greyish-white colonies with a grey-black reverse The conidia are single-celled, pale brown and oval in form Their size ranges from 4–9 x 6–10 µm and their development is annellidic


Pseudallescheria boydii is an emerging opportunist Immune response is characterized by TLR2 recognition of P boydii derived α-glucans, while TLR4 mediates the recognition of P boydii derived rhamnomannans Human infection takes one of two forms: mycetoma 99% of infections, a chronic, subcutaneous disease, and pseudallescheriasis, which includes all other forms of the disease commonly presented in the central nervous system, lungs, joints and bone The former can also be distinguished by the presence of sclerotia, or granules, which are typically absent in pseudallescheriasis-type infections Infection is initiated via inhalation or traumatic implantation in the skin Infection can lead to arthritis, otitis, endocarditis, sinusitis, and other manifestations Masses of hyphae can form "fungus balls" in the lungs While "fungus balls" can also form in other organs, they are commonly derived from host necrotic tissue resulting from nodular infarction and thrombosis of lung vessels following infection

This species is second in prevalence after Aspergillus fumigatus as a fungal pathogen in cystic fibrosis lung It causes allergic bronchopulmonary disease and chronic lung lesions that resemble aspergillosis Infections can also occur in immunocompetent individuals, usually in the lungs and upper respiratory tract Infections in the CNS, which are rare, present as neutrophilic meningitis or multiple brain abscesses and have a mortality rate of up to 75% Infections have also been observed in animals, notably corneal infection, abdominal mycetoma and disseminated infections in dogs and horses Transient colonization is more likely than disease However, invasive pseudoallescheriasis can be found in patients with prolonged neutropenia, high-dose corticosteroid therapy and allotransplantation of bone marrow Pseudallescheria boydii has also been implicated in pneumonia subsequent to near-drowning events with infection developing anywhere between a few weeks to several months after exposure yielding high mortality Dissemination of the organism to the central nervous system has been observed in some cases This species is also known as a non-invasive colonist of the external ear and airways of patients with poor lung or sinus clearance, and the first documented case of human pseudallescheriasis involved the ear canal It has also been implicated in infection of joints following traumatic injury, and these infections can progress to osteomyelitis Infections of the skin and cornea have also been reported Typical host-related risk factors for infection include lymphopenia, steroid treatment, serum albumin levels of < 3 mg/dL and neutropenia


Detection and diagnosis of S apiospermum is possible through isolation of the fungus in culture or through cytology and histopathology in the tissues of diseased individuals In mycetoma-type infections, a confluence of symptoms is necessary for diagnosis, including tumefaction, draining sinuses and extrusion of grains Furthermore, P boydii grains and hyphae should be cultured and observed microscopically after staining with H&E, PAS stain, Tissue Gram or Grogott-Gomori methenamine silver A radiological diagnosis may be helpful in elucidating the extent of the disease in terms of bone and soft tissue involvement Scedosporium-caused eumycetomas have been found to have thick-walled cavities and grains appearing as hyperreflective echoes on scans, while actinomycetomas show fine echoes at the bottom of cavities

Direct detection is possible in samples histochemically stained in 20% KOH followed by fluorescence microscopy with antibody The characteristic shape, texture and colour of tissues can help identify S apiospermum grains, which are often surrounded by an eosinophilic zone Histopathologically, hyalohyphomycotic fungi like Scedosporium spp, Aspergillus spp, Fusarium spp and Petriella spp are similar in that they show septation of hyphae at regular intervals, have dichotomous branching and invade blood vessels However, Scedosporium presents more irregular branching, sometimes with terminal or intercalary chlamydospores In serum, Scedosporium infections can be detected by counterimmunoelectrophoresis Molecular diagnostics appear to be promising in complementing current conventional diagnostic methods

Culture detection is accomplished by rinsing "grains" in 70% ethanol and sterile saline solution to avoid bacterial contamination prior to inoculation on growth medium Selection of Scedosporium growth can be achieved on Leonian's agar supplemented with 10 g/mL benomyl, or on media containing cycloheximide or amphotericin B Optimal incubation is at a temperature of 25–35 °C 77–95 °F


Pseudallescheria boydii is resistant to amphotericin B and nearly all other antifungal drugs Consequently, there is currently no consistently effective antifungal therapy for this agent Miconazole has shown the best in vivo activity; however, itraconazole, fluconazole, ketoconazole and voriconazole have also been used in treatment, albeit with less success In an in vitro environment, terbinafine has been found to work in synergy with azoles against P boydii Echinocandins, such as caspofungin and sordarins, have shown promise in in vitro assays CMT-3, a chemically modified tetracycline, has also shown to be active in vitro against P boydii


In the United States, P boydii is the most common causal agent of eumycetoma, and tends to be more common in men than in women, particularly in the 20- to 45-year-old age group In the United States, the incidence of infection by S apiospermum between 1993 and 1998 was 082; this figure increased to 133 by 2005 Pseudallescheria boydii infection was implicated in the deaths of three athletes injured during the opening ceremony of the 1997 Maccabiah Games when the Maccabiah bridge collapsed in the Yarkon River


  1. ^ "Pseudallescheria boydii Shear McGinnis, AA Padhye & Ajello, Mycotaxon 14 1: 97 1982" MycoBank International Mycological Association Retrieved 2014-11-23 
  2. ^ Pseudallescheria at the US National Library of Medicine Medical Subject Headings MeSH
  3. ^ Janda-Ulfig K, Ulfig K, Cano J, Guarro J; Ulfig; Cano; Guarro June 2008 "A study of the growth of Pseudallescheria boydii isolates from sewage sludge and clinical sources on tributyrin, rapeseed oil, biodiesel oil and diesel oil" Ann Agric Environ Med 15 1: 45–9 PMID 18581978 CS1 maint: Multiple names: authors list link
  4. ^ Guarro J, Kantarcioglu AS, Horré R, et al June 2006 "Scedosporium apiospermum: changing clinical spectrum of a therapy-refractory opportunist" Med Mycol 44 4: 295–327 doi:101080/13693780600752507 PMID 16772225 
  5. ^ Wiederhold, NP; Lewis, RE June 2009 "Antifungal activity against Scedosporium species and novel assays to assess antifungal pharmacodynamics against filamentous fungi" Medical mycology 47 4: 422–32 doi:101080/13693780802510224 PMID 19058049 
  6. ^ a b Tal, Alon 2002 Pollution in a Promised Land: An Environmental History of Israel University of California Press ISBN 0-520-23428-6 
  7. ^ Shear, CL 1922 "Life history of an undescribed ascomycete isolated from a granular mycetoma of man" Mycologia 14 5: 239–43 doi:102307/3753469 
  8. ^ Malloch, D 1970 "New concepts in the Microascaceae illustrated by two species" Mycologia 62 4: 727–740 doi:102307/3757662 
  9. ^ McGinnis, MR; Padhye, AA; Ajello, L 1982 "Pseudallescheria Negroni et Fischer, 1943 and its later synonym Petrielldium Malloch, 1970" Mycotaxon 14 1: 94–102 
  10. ^ a b c d e f g h i j k l m n o p q Cortez, K J; Roilides, E; Quiroz-Telles, F; Meletiadis, J; Antachopoulos, C; Knudsen, T; Buchanan, W; Milanovich, J; Sutton, D A; Fothergill, A; Rinaldi, M G; Shea, Y R; Zaoutis, T; Kottilil, S; Walsh, T J 17 January 2008 "Infections Caused by Scedosporium spp" Clinical Microbiology Reviews 21 1: 157–197 doi:101128/CMR00039-07 PMC 2223844  PMID 18202441 
  11. ^ a b c d e f g h i j k l de Hoog, G S; Guarro, J; Gené, J; Figueras, M J 2000 Atlas of Clinical Fungi Second ed American Society for Microbiology ISBN 90-70351-43-9 
  12. ^ Liscano, K Salfelder ; assisted by TR de; Sauerteig, E 1990 Atlas of fungal pathology Dordrecht: Kluwer Academic Publishers ISBN 0792389352 
  13. ^ a b c d e Patterson, Thomas F; McGinnis, Michael R "Pseudallescheria spp" www doctorfungusorg Retrieved 28 October 2014 
  14. ^ Gilgado, F; Cano, J; Gené, J; Guarro, J 2005 "Molecular phylogeny of the Pseudallescheria boydii species complex: proposal of two new species" Journal of Clinical Microbiology 43 10: 4930–42 doi:101128/jcm43104930-49422005 PMC 1248451  PMID 16207945 
  15. ^ a b c d e f g Prober, editor, Sarah Long ; associate editors, Larry K Pickering, Charles G 2012 Principles and practice of pediatric infectious disease 4th ed Edinburgh: Elsevier/Saunders ISBN 9781437727029 CS1 maint: Extra text: authors list link
  16. ^ a b c d de Hoog, GS; Marvin-Sikkema, FD; Lahpoor, GA; Gottschall, JC; Prins, RA; Guého, E 1994 "Ecology and physiology of the emerging opportunistic fungi Pseudallescheria boydii and Scedosporium prolificans" Mycoses 37 3–4: 71–8 doi:101111/j1439-05071994tb00780x PMID 7845423 
  17. ^ Figueiredo, Rodrigo Tinoco; Bittencourt, Vera Carolina B; Lopes, Lívia Cristina L; Sassaki, Guilherme; Barreto-Bergter, Eliana 2012 "Toll-like receptors TLR2 and TLR4 recognize polysaccharides of Pseudallescheria boydii cell wall" Carbohydrate Research 356: 260–264 doi:101016/jcarres201202028 PMID 22507831 
  18. ^ a b c d e Dolin, edited by Gerald L Mandell, John E Bennett, Raphael 2000 Mandell, Douglas, and Bennett's principles and practice of infectious diseases 5th ed Philadelphia: Churchill Livingstone ISBN 0-443-07593-X CS1 maint: Extra text: authors list link
  19. ^ Kershaw, P; Freeman, R; Templeton, D; DeGirolami, P C; DeGirolami, U; Tarsy, D; Hoffmann, S; Eliopoulos, G; Karchmer, A W 1 April 1990 "Pseudallescheria boydii Infection of the Central Nervous System" Archives of Neurology 47 4: 468–472 doi:101001/archneur199000530040126029 PMID 2181980 
  20. ^ a b Ender, Peter T; Dolan, Matthew J 1997 "Pneumonia Associated with Near‐Drowning" Clinical Infectious Diseases 25 4: 896–907 doi:101086/515532 PMID 9356805 
  21. ^ Rippon, John Willard 1988 Medical mycology : the pathogenic fungi and the pathogenic actinomycetes 3rd ed Philadelphia, PA: Saunders ISBN 0721624448 
  22. ^ Ajello, L; Hay, R J 1997 Medical Mycology Vol 4 Topley & Wilson's Microbiology and Infectious Infections 9th ed London: Arnold 
  23. ^ Thornton, C R 25 March 2009 "Tracking the Emerging Human Pathogen Pseudallescheria boydii by Using Highly Specific Monoclonal Antibodies" Clinical and Vaccine Immunology 16 5: 756–764 doi:101128/CVI00061-09 PMC 2681584  PMID 19321690 

pseudallescheria boydii, pseudallescheria boydii colony morphology, pseudallescheria boydii complex, pseudallescheria boydii drowning, pseudallescheria boydii image, pseudallescheria boydii infection, pseudallescheria boydii life cycle, pseudallescheria boydii mycetoma, pseudallescheria boydii pronunciation, pseudallescheria boydii treatment

Pseudallescheria boydii Information about

Pseudallescheria boydii

  • user icon

    Pseudallescheria boydii beatiful post thanks!


Pseudallescheria boydii
Pseudallescheria boydii
Pseudallescheria boydii viewing the topic.
Pseudallescheria boydii what, Pseudallescheria boydii who, Pseudallescheria boydii explanation

There are excerpts from wikipedia on this article and video

Random Posts

La Porte, Indiana

La Porte, Indiana

La Porte French for "The Door" is a city in LaPorte County, Indiana, United States, of which it is t...
Fernando Montes de Oca Fencing Hall

Fernando Montes de Oca Fencing Hall

The Fernando Montes de Oca Fencing Hall is an indoor sports venue located in the Magdalena Mixhuca S...
My Everything (The Grace song)

My Everything (The Grace song)

"My Everything" was Grace's 3rd single under the SM Entertainment, released on November 6, 2006 Unli...
Turkish Straits

Turkish Straits

The Turkish Straits Turkish: Türk Boğazları are a series of internationally significant waterways in...