Biology:Paecilomyces variotii

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Short description: Species of fungus

Paecilomyces variotii
Paecilomyces variotii culture.jpg
Scientific classification edit
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Eurotiomycetes
Order: Eurotiales
Family: Thermoascaceae
Genus: Paecilomyces
Species:
P. variotii
Binomial name
Paecilomyces variotii
Bainier

Paecilomyces variotii is a common environmental mold that is widespread in composts, soils and food products. It is known from substrates including food, indoor air, wood, soil and carpet dust.[1][2][3] Paecilomyces variotii is the asexual state of Byssochlamys spectabilis, a member of the Phylum Ascomycota (Family Trichocomaceae).[4] However, the Byssochlamys state is rarely observed in culture due to the heterothallic nature of this species (i.e., it requires culturing of positive and negative strains in co-culture to produce the teleomorph). Paecilomyces variotii is fast growing, producing powdery to suede-like colonies that are yellow-brown or sand-colored.[5] It is distinguishable from microscopically similar microfungi, such as the biverticillate members of the genus Penicillium (affiliated with the genus Talaromyces) by its broadly ellipsoidal to lemon-shaped conidia, loosely branched conidiophores and phialides with pointed tips. Ascospores of the sexual state, B. spectabilis, are strongly heat-resistant. As such, the fungus is a common contaminant of heat-treated foods and juices.[4] It is also known from decaying wood and creosote-treated wood utility poles.[4][5] Paecilomyces variotii has been associated with a number of infective diseases of humans and animals.[6] It is also an important indoor environmental contaminant.[7]

Morphology

The colonies are usually flat, powdery to suede-like and funiculose or tufted.[8] The color is initially white, and becomes yellow, yellow-brown, or sand-colored as they mature. A sweet aromatic odor may be associated with older cultures.[9] Colonies of P. variotii are fast growing and mature within 3 days. Colonies grown on Sabouraud's dextrose agar reach about 7–8 mm after one week. Colonies on CYA are flat, floccose in texture, produce brown or olive brown from conidia, and range in diameter from 30-79 mmn in one week.[10] Colonies on malt extract agar reach 70 mm diameter or more, otherwise very similar in appearance to those on CYA. Colonies on G25N media reach 8–16 mm diameter, similar to on CYA but with predominantly white mycelium. Microscopically, the spore-bearing structures of P. variotii consist of a loosely branched,[11] irregularly brush-like conidiophores with phialides at the tips.[4][8] The phialides are swollen at the base, and gradually taper to a sharp point at the tip.[11] Conidia are single-celled, hyaline, and are borne in chains with the youngest at the base.[4] Chlamydospores (thick-walled vegetative resting structures) are occasionally produced singly or in short chains.[12]

Genetics

This fungus is heterothallic, and mating experiments have shown that P. variotii can form ascomata and ascospores in culture when compatible mating types are present.[1][4] The teleomorph of P. variotii, Byssochlamys spectabilis, is rarely observed in cultures from environmental or clinical specimens, which tend to be colonized by a single mating type.[4] The genome sequences of two isolates of P. variotii of opposite mating type have been generated.[13]

Ecology

This species is thermophilic, able to grow at high temperatures as high as 50–60 °C.[4][9] It can withstand brief exposures of up to 15 min at 80–100 °C.[14] Accordingly, it typically causes spoilage of food products following pasteurization or other heat-treatments (e.g., curry sauces, fruit juices).[14][15] It also has been reported as a contaminant in salami and margarine.[7] The fungus is known from a number of non-food items including compost, rubber, glue, urea-formaldehyde foam insulation and creosote-treated wooden poles.[7][15] The combination of its ability to survive significant heat stress and its ability to break-down aromatic hydrocarbons has led to interest in P. variotii as a potential candidate organism to assist in bioremediation.

Health significance

Although frequently encountered as a contaminant in clinical specimens, P. variotii is an uncommon causative agent of human and animal infections, but is considered to be an emerging agent of opportunistic disease, particularly in immunocompromised individuals. It has been suggested that the extremotolerant nature of the fungus contributes to its pathogenic potential. Pneumonia due to P. variotii has been reported, albeit rarely, in the medical literature.[16][17] Most cases are known from diabetics or individuals subject to long-term corticosteroid treatment for other diseases.[18][19] P. variotii has also been reported as a causative agent of sinusitis,[20][21][22] endophthalmitis,[23][24][25] wound infection following tissue transplant,[26] cutaneous hyalohyphomycosis,[27][28][29] onychomycosis,[30] osteomyelitis,[31] otitis media[32] and dialysis-related peritonitis.[6][33] It has also been reported from mastitis in a goat, and as an agent of mycotic infections of dogs and horses. [citation needed] Besides clinical samples, the fungus is a common contaminant of moisture-damaged materials in the indoor environment including carpet, plaster and wood.[7] It is commonly found in indoor air samples and may contribute to indoor allergy.[7] This species produces the mycotoxin viriditoxin,[7] via the action of six enzymes encoded within a cluster of genes within the genome.[34]

References

  1. ↑ 1.0 1.1 "Sexual reproduction as the cause of heat resistance in the food spoilage fungus Byssochlamys spectabilis (anamorph Paecilomyces variotii)". Applied and Environmental Microbiology 74 (5): 1613–9. March 2008. doi:10.1128/aem.01761-07. PMID 18192427. Bibcode: 2008ApEnM..74.1613H. 
  2. ↑ Fungi and food spoilage (3rd ed.). 2009. Bibcode: 2009ffs..book.....P. 
  3. ↑ "Apophysomyces variabilis infections in humans". Emerging Infectious Diseases 17 (1): 134–5. January 2011. doi:10.3201/eid1701.101139. PMID 21192877. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 "Identification of Paecilomyces variotii in clinical samples and settings". Journal of Clinical Microbiology 48 (8): 2754–61. August 2010. doi:10.1128/jcm.00764-10. PMID 20519470. 
  5. ↑ 5.0 5.1 Ellis, David (May 2001). "Paecilomyces variotii." Mycology Online". The University of Adelaide. 
  6. ↑ 6.0 6.1 "Paecilomyces variotii peritonitis in an infant on automated peritoneal dialysis". Pediatric Nephrology 14 (5): 365–6. May 2000. doi:10.1007/s004670050775. PMID 10805461. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 "Common and important species of fungi and actinomycetes in indoor environment". Microorganisms in Home and Indoor Work Environments. 2001. pp. 285–473. ISBN 978-0-203-30293-4. 
  8. ↑ 8.0 8.1 "Paecilomyces Species.". Paecilomyces Species. Nov 2013. 
  9. ↑ 9.0 9.1 Atlas of Clinical Fungi. 1 (2nd ed.). Reus, Spain: Universitat Rovira i Virgili. 2000. ISBN 978-90-70351-43-4. 
  10. ↑ Pitt, John; Hocking, Ailsa D. (1985). "Fungi and Food Spoilage". Sydney: Academic: 186–96. 
  11. ↑ 11.0 11.1 Paecilomyces and some allied hyphomycetes. 6. 1974. 1–119. ISBN 978-94-91751-00-4. https://www.studiesinmycology.org/sim/Sim06/fulltext.htm. 
  12. ↑ "Paecilomyces and Some Allied Hyphomycetes". Transactions of the British Mycological Society 64: 174. 1975. doi:10.1016/s0007-1536(75)80098-2. 
  13. ↑ "Paecilomyces variotii (Eurotiales)". Frontiers in Microbiology 9: 3058. 2018. doi:10.3389/fmicb.2018.03058. PMID 30619145. 
  14. ↑ 14.0 14.1 "Heat Resistance of Paecilomyces variotii in Sauce and Juice". Journal of Industrial Microbiology and Biotechnology 24 (4): 227–30. 2000. doi:10.1038/sj.jim.2900794. 
  15. ↑ 15.0 15.1 Introduction to food- and airborne fungi (7th ed.). Centraalbureau voor Schimmelcultures. 2004. ISBN 978-90-70351-52-6. 
  16. ↑ "Pneumonia from Paecilomyces in a 67-year-old immunocompetent man". Chest 132 (4): 710. 2007. doi:10.1378/chest.132.4_meetingabstracts.710. 
  17. ↑ "Paecilomyces: emerging fungal pathogen". Chest 128 (4): 425S. 2005. doi:10.1378/chest.128.4_meetingabstracts.425s. 
  18. ↑ "Paecilomyces varioti pneumonia in a patient with diabetes mellitus". Journal of Diabetes and Its Complications 6 (2): 150–3. 1992. doi:10.1016/1056-8727(92)90027-i. PMID 1611140. 
  19. ↑ "Paecilomyces variotii as an Emergent Pathogenic Agent of Pneumonia". Case Reports in Infectious Diseases 2013: 1–3. 2013. doi:10.1155/2013/273848. PMID 23819077. 
  20. ↑ "Mycotic sinusitis". Acta Oto-rhino-laryngologica Belgica 51 (4): 339–52. 1997. PMID 9444380. 
  21. ↑ "Paecilomycosis of the maxillary sinus". Mykosen 27 (5): 242–51. May 1984. doi:10.1111/j.1439-0507.1984.tb02025.x. PMID 6540366. 
  22. ↑ "Paecilomyces variotii. An unusual cause of isolated sphenoid sinusitis". Archives of Otolaryngology–Head & Neck Surgery 114 (5): 567–9. May 1988. doi:10.1001/archotol.1988.01860170097028. PMID 3355698. 
  23. ↑ "Endogenous fungal endophthalmitis caused by Paecilomyces variotii". Eye 13 ( Pt 1): 113–6. 1999. doi:10.1038/eye.1999.23. PMID 10396397. 
  24. ↑ "Fungal endophthalmitis caused by Paecilomyces variotii following cataract surgery: a presumed operating room air-conditioning system contamination". Acta Ophthalmologica Scandinavica 82 (2): 232–5. April 2004. doi:10.1111/j.1600-0420.2004.00235.x. PMID 15043549. 
  25. ↑ "Fungal endophthalmitis caused by Paecilomyces variotii, in an immunocompetent patient, following intraocular lens implantation". Indian Journal of Medical Microbiology 28 (3): 253–4. 2010. doi:10.4103/0255-0857.66491. PMID 20644318. 
  26. ↑ "Delayed sternotomy wound infection due to Paecilomyces variotii in a lung transplant recipient". The Journal of Heart and Lung Transplantation 21 (10): 1131–4. October 2002. doi:10.1016/s1053-2498(02)00404-7. PMID 12398880. 
  27. ↑ "Hyalohyphomycosis caused by Paecilomyces variotii in an obstetrical patient". European Journal of Epidemiology 12 (1): 33–5. February 1996. doi:10.1007/bf00144425. PMID 8817175. 
  28. ↑ "Hyalohyphomycosis caused by Paecilomyces variotii: a case report, animal pathogenicity and 'in vitro' sensitivity". Antonie van Leeuwenhoek 62 (3): 225–30. October 1992. doi:10.1007/bf00582583. PMID 1416918. 
  29. ↑ "First reported case of subcutaneous hyalohyphomycosis caused by Paecilomyces variotii". International Journal of Dermatology 52 (6): 711–3. June 2013. doi:10.1111/j.1365-4632.2012.05761.x. PMID 23679876. 
  30. ↑ "Onychomycosis due to Paecilomyces variotii. Case report and review". Journal de Mycologie Médicale 8 (1): 32–33. 1998. 
  31. ↑ "Multifocal osteomyelitis caused by Paecilomyces varioti in a patient with chronic granulomatous disease". Infection 23 (1): 55–7. 1995. doi:10.1007/bf01710060. PMID 7744494. 
  32. ↑ "Chronic suppurative otitis media caused by Paecilomyces variotii". Journal of Medical and Veterinary Mycology 33 (1): 59–61. 1995. doi:10.1080/02681219580000121. PMID 7650580. 
  33. ↑ "Paecilomyces variotii in peritoneal dialysate". Journal of Clinical Microbiology 31 (9): 2392–5. September 1993. doi:10.1128/jcm.31.9.2392-2395.1993. PMID 8408561. 
  34. ↑ Urquhart, AS; Hu, J; Chooi, YH; Idnurm, A (2019). "The fungal gene cluster for biosynthesis of the antibacterial agent viriditoxin". Fungal Biology and Biotechnology 6: 2. doi:10.1186/s40694-019-0072-y. ISSN 2054-3085. PMID 31304040. 

Wikidata ☰ Q1776536 entry




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