Saksenaea vasiformis

Last updated

Saksenaea vasiformis
Scientific classification
Kingdom:
Fungi
Division:
Zygomycota
Class:
Mucoromycotina
Order:
Mucorales
Family:
Saksenaeaceae
Genus:
Saksenaea
Species:
S. vasiformis

S.B.Saksena (1953)
Binomial name
Saksenaea vasiformis
S.B.Saksena (1953)

Saksenaea vasiformis is an infectious fungus associated with cutaneous or subcutaneous lesions following trauma. [1] [2] It causes opportunistic infections as the entry of the fungus is through open spaces of cutaneous barrier [3] ranging in severity from mild to severe or fatal. [1] It lives in soils worldwide, [3] but is considered as a rare human pathogen since only 38 cases were reported as of 2012. [4] Saksenaea vasiformis usually fails to sporulate on the routine culture media, [3] creating a challenge for early diagnosis, which is essential for a good prognosis. [4] Infections are usually treated using a combination of amphotericin B and surgery. [4] Saksenaea vasiformis is one of the few fungi known to cause necrotizing fasciitis or "flesh-eating disease". [5]

Contents

Description

Saksenaea vasiformis was initially described as a new mucoraceous fungus in a new genus Saksenaea in 1953 by Dr. S. B. Saksena. [6] It was isolated from Patharia forest soil in India and distinguishably different from other species in morphology of sporangia (flask-shaped) and the method of spore discharge. [6] The name "vasiformis" came from the flask-shape of sporangiophore. [7] Since 1953, it has been isolated from various countries including Panama, Israel, Honduras, and the southern United States. [3] This species is the only species belong to genus Saksenaea, [3] although two new species, which are Saksenaea oblongispora and Saksenaea erythrospora, were proposed in 2010. [8] Detailed microscopic observation displayed similar flask shape of sporangiophores and the phylogenic analysis indicated that these isolates (S. vasiformis, S. oblongispora and S. erythrospora) belong to the same genus Saksenaea. [8]

This species is associated with Apophysomyces elegans, a member of family Mucoraceae. Despite the significant differences of morphological characteristics of sporangia and the manner of sporangium formation, these two species are associated, usually in medical literature, due to similar disease manifestation in human: cutaneous or subcutaneous infections. [3] [7] Infections involving these two species (S. vasiformis and A. elegans) cause rapid necrotizing vasculitis that leads to thrombosis and tissue necrosis in organisms’ vascular lumen. [9]

Cultural characteristics

Saksenaea vasiformis very rapidly grows in growth media, producing sterile hyphae. [3] [8] Induction of sporulation is difficult with routine fungal media used in the most of clinical laboratories, but it can be stimulated to sporulate rapidly (5 to 7 days) by incubating the yeast-malt-dextrose agar at 32 °C. [10] The identification of this species is not problematic after sporulation event because of its characteristic flask-shaped sporangium with spherical venter and a distinct dome-shped columella and dichotomously branched rhizoid complex. [3] [6] On top of the venter, there is a neck with closed apex with a mucilaginous plug. [6] Inside of the neck are the sporangiophores, which are liberated by the dissolution of the mucilaginous plug. [6]

Pathogenesis

Saksenaea vasiformis is normally present in soil and does not cause human infection unless it is introduced to the open site where the cutaneous barrier no longer exists. [11] This is why this species causes an opportunistic infection following a traumatic event that breaks the cutaneous barrier. Infections were reported in the United States, Australia, Norway, New Zealand, Spain, India, French Guiana, France, India and Greece. [1] [4] The first human infection by S. vasiformis was reported in 1976 in a 19-year-old male with cranial and facial wounds incurred during an automobile accident. [12]

Saksenaea vasiformis usually causes cutaneous or subcutaneous zygomycosis, but can also cause primary sinusitis and rhinocerebral disease. [1] Cutaneous diseases by S. vasiformis present red blisters. [13] with necrotic ulcers [14] or raised red to purple lesions. [15] Infections by S. vasiformis are normally localized and indolent, but in some cases infection is disseminated or becomes highly invasive, and these cases were all fatal. [3]

Early diagnosis is the key to survival of the patients, but the diagnosis of the disease is hard due to difficulties in stimulating sporulation. Furthermore, there has been only 38 cases of infections reported as of 2012 [4] and the author of the paper suggested that low number of cases reported can be due to lack of awareness of this species in clinical environment, high mortality rate, and largely, microbiological and clinical bias resulted from difficulties in stimulating sporulation of this species. To ease the identification of fungus producing sterile mycelium such as S. vasiformis and A. elegans, exoantigen test has been developed. For S. vasiformis, even though exoantigen testing is helpful with positive test, it is rarely used because of the high false-negative rate, requiring confirmation by sporulating morphology with all the negative tests. [3] — see cultural characteristics.

Human hosts are usually immunocompetent with open lesion that acts as a portal entry of the fungus into the body. There has been some reported cases of immunocompromised hosts due to steroid treatment, antibiotic therapy, and compromised immune system due to underlying disease is also known as a risk factor. [3] For example, S. vasiformis infection has been seen in some patients with preleukemia, [14] bladder cancer [16] and diabetes mellitus. [17] Moreover, S. vasiformis causes infections in bovines [18] and cetaceans such as bottlenose dolphins, killer whales, and Pacific White-sided dolphins in with A. elegans. [7]

Treatment

Infections by S. vasiformis are mainly treated with drug amphotericin B because this species is resistant to many antifungal agents. [4] The side effect of amphotericin B is renal toxicity, but the chances of side effect can be reduced by administering amphotericin B in incremental doses to reach maximum daily dose of 0.5 to 0.75 mg/kg. [4] Furthermore, amphotericin B deoxycholate is more nephrotoxic than liposomal amphotericin B; due to the expense of liposomal amphotericin B, many of the patients were unable to afford this therapy, resulting in fatal outcome. [4] In addition, another antifungal agent, posaconazole, was able to successfully treat disseminated infection by S. vasiformis in vitro, suggesting that it could be used as an alternative to amphotericin B for the treatment of the infections. [19]

Along with the drug treatment, patients are recommended to receive an aggressive surgical debridement or an amputation in some severe cases. This is an important for the infection to be treated efficiently and effectively [3] [4] because necrotic tissues may act as a barrier to penetration of drug to the site of infection. [4]

It is essential to treat infections appropriately and as soon as possible to decrease the mortality rate as mortality rate of untreated cases is almost 100% and that of properly treated cutaneous diseases is only around 10%. [20] [21]

Related Research Articles

<span class="mw-page-title-main">Zygomycosis</span> Medical condition

Zygomycosis is the broadest term to refer to infections caused by bread mold fungi of the zygomycota phylum. However, because zygomycota has been identified as polyphyletic, and is not included in modern fungal classification systems, the diseases that zygomycosis can refer to are better called by their specific names: mucormycosis, phycomycosis and basidiobolomycosis. These rare yet serious and potentially life-threatening fungal infections usually affect the face or oropharyngeal cavity. Zygomycosis type infections are most often caused by common fungi found in soil and decaying vegetation. While most individuals are exposed to the fungi on a regular basis, those with immune disorders (immunocompromised) are more prone to fungal infection. These types of infections are also common after natural disasters, such as tornadoes or earthquakes, where people have open wounds that have become filled with soil or vegetative matter.

<span class="mw-page-title-main">Sporotrichosis</span> Medical condition

Sporotrichosis, also known as rose handler's disease, is a fungal infection that may be localised to skin, lungs, bone and joint, or become systemic. It presents with firm painless nodules that later ulcerate. Following initial exposure to Sporothrix schenckii, the disease typically progresses over a period of a week to several months. Serious complications may develop in people who have a weakened immune system.

Phycomycosis is an uncommon condition of the gastrointestinal tract and skin most commonly found in dogs and horses. The condition is caused by a variety of molds and fungi, and individual forms include pythiosis, zygomycosis, and lagenidiosis. Pythiosis is the most common type and is caused by Pythium, a type of water mould. Zygomycosis can also be caused by two types of zygomycetes, Entomophthorales and Mucorales. The latter type of zygomycosis is also referred to as mucormycosis. Lagenidiosis is caused by a Lagenidium species, which like Pythium is a water mould. Since both pythiosis and lagenidiosis are caused by organisms from the class Oomycetes, they are sometimes collectively referred to as oomycosis.

<i>Basidiobolus ranarum</i> Species of fungus

Basidiobolus ranarum is a filamentous fungus with worldwide distribution. The fungus was first isolated by Eidam in 1886. It can saprophytically live in the intestines of mainly cold-blooded vertebrates and on decaying fruits and soil. The fungus prefers glucose as a carbon source and grows rapidly at room temperature. Basidiobolus ranarum is also known as a cause of subcutaneous zygomycosis, usually causing granulomatous infections on a host's limbs. Infections are generally geographically limited to tropical and subtropical regions such as East and West Africa. Subcutaneous zygomycosis caused by B. ranarum is a rare disease and predominantly affects children and males. Common subcutaneous zygomycosis shows characteristic features and is relatively easy to be diagnosed; while, certain rare cases might show non-specific clinical features that might pose a difficulty on its identification. Although disease caused by this fungus is known to resolve spontaneously on its own, there are a number of treatments available.

<i>Apophysomyces</i> Genus of fungi

Apophysomyces is a genus of filamentous fungi that are commonly found in soil and decaying vegetation. Species normally grow in tropical to subtropical regions.

<i>Mucor mucedo</i> Species of fungus

Mucor mucedo, commonly known as the common pinmould, is a fungal plant pathogen and member of the phylum Mucoromycota and the genus Mucor. Commonly found on soil, dung, water, plants and moist foods, Mucor mucedo is a saprotrophic fungus found world-wide with 85 known strains. It is often mistaken for Rhizopus rots on fruits due to similar mould growth shape and colour. Contrastingly, however, Mucor mucedo is found to grow on a wide range of stored grains and plants, including cucumber and tomato. Discovered in Italy in 1729 by P.A. Micheli and later noted by Carl Linnaeus in 1753 in the Species Plantarum, Mucor mucedo was originally classified as Mucor vulgaris by Micheli but later classified synonymous under name Mucor mucedo. The species was redescribed as Ascophora mucedo by H.J. Tode in 1790 but this type resided in a stoloniferous habitat and was later made the type of new genus Rhizopus.

<i>Setosphaeria rostrata</i> Pathogenic fungus

Setosphaeria rostrata is a heat tolerant fungus with an asexual reproductive form (anamorph) known as Exserohilum rostratum. This fungus is a common plant pathogen, causing leaf spots as well as crown rot and root rot in grasses. It is also found in soils and on textiles in subtropical and tropical regions. Exserohilum rostratum is one of the 35 Exserohilum species implicated uncommonly as opportunistic pathogens of humans where it is an etiologic agent of sinusitis, keratitis, skin lesions and an often fatal meningoencephalitis. Infections caused by this species are most often seen in regions with hot climates like Israel, India and the southern USA.

Exophiala jeanselmei is a saprotrophic fungus in the family Herpotrichiellaceae. Four varieties have been discovered: Exophiala jeanselmei var. heteromorpha, E. jeanselmei var. lecanii-corni, E. jeanselmei var. jeanselmei, and E. jeanselmei var. castellanii. Other species in the genus Exophiala such as E. dermatitidis and E. spinifera have been reported to have similar annellidic conidiogenesis and may therefore be difficult to differentiate.

<span class="mw-page-title-main">Mucormycosis</span> Fungal infection

Mucormycosis, also known as black fungus, is a serious fungal infection that comes under fulminant fungal sinusitis, usually in people who are immunocompromised. It is curable only when diagnosed early. Symptoms depend on where in the body the infection occurs. It most commonly infects the nose, sinuses, eyes and brain resulting in a runny nose, one-sided facial swelling and pain, headache, fever, blurred vision, bulging or displacement of the eye (proptosis), and tissue death. Other forms of disease may infect the lungs, stomach and intestines, and skin.

Entomophthoramycosis is a mycosis caused by Entomophthorales.

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.

<i>Exophiala dermatitidis</i> Species of fungus

Exophiala dermatitidis is a thermophilic black yeast, and a member of the Herpotrichiellaceae. While the species is only found at low abundance in nature, metabolically active strains are commonly isolated in saunas, steam baths, and dish washers. Exophiala dermatitidis only rarely causes infection in humans, however cases have been reported around the world. In East Asia, the species has caused lethal brain infections in young and otherwise healthy individuals. The fungus has been known to cause cutaneous and subcutaneous phaeohyphomycosis, and as a lung colonist in people with cystic fibrosis in Europe. In 2002, an outbreak of systemic E. dermatitidis infection occurred in women who had received contaminated steroid injections at North Carolina hospitals.

<i>Apophysomyces variabilis</i> Species of fungus

Apophysomyces variabilis is an emerging fungal pathogen that can cause serious and sometimes fatal infection in humans. This fungus is a soil-dwelling saprobe with tropical to subtropical distribution. It is a zygomycete that causes mucormycosis, an infection in humans brought about by fungi in the order Mucorales. Infectious cases have been reported globally in locations including the Americas, Southeast Asia, India, and Australia. Apophysomyces variabilis infections are not transmissible from person to person.

<i>Lichtheimia corymbifera</i> Species of fungus

Lichtheimia corymbifera is a thermophilic fungus in the phylum Zygomycota. It normally lives as a saprotrophic mold, but can also be an opportunistic pathogen known to cause pulmonary, CNS, rhinocerebral, or cutaneous infections in animals and humans with impaired immunity.

Scedosporiosis is the general name for any mycosis - i.e., fungal infection - caused by a fungus from the genus Scedosporium. Current population-based studies suggest Scedosporium prolificans and Scedosporium apiospermum to be among the most common infecting agents from the genus, although infections caused by other members thereof are not unheard of. The latter is an asexual form (anamorph) of another fungus, Pseudallescheria boydii. The former is a “black yeast”, currently not characterized as well, although both of them have been described as saprophytes.

Histoplasma duboisii is a saprotrophic fungus responsible for the invasive infection known as African histoplasmosis. This species is a close relative of Histoplasma capsulatum, the agent of classical histoplasmosis, and the two occur in similar habitats. Histoplasma duboisii is restricted to continental Africa and Madagascar, although scattered reports have arisen from other places usually in individuals with an African travel history. Like, H. capsulatum, H. duboisii is dimorphic – growing as a filamentous fungus at ambient temperature and a yeast at body temperature. It differs morphologically from H. capsulatum by the typical production of a large-celled yeast form. Both agents cause similar forms of disease, although H. duboisii predominantly causes cutaneous and subcutaneous disease in humans and non-human primates. The agent responds to many antifungal drug therapies used to treat serious fungal diseases.

Cunninghamella bertholletiae is a species of zygomycetous fungi in the order Mucorales. It is found globally, with increased prevalence in Mediterranean and subtropical climates. It typically grows as a saprotroph and is found in a wide variety of substrates, including soil, fruits, vegetables, nuts, crops, and human and animal waste. Although infections are still rare, C. betholletiae is emerging as an opportunistic human pathogen, predominantly in immunocompromised people, leukemia patients, and people with uncontrolled diabetes. Cunninghamella bertholletiae infections are often highly invasive, and can be more difficult to treat with antifungal drugs than infections with other species of the Mucorales, making prompt and accurate recognition and diagnosis of mycoses caused by this fungus an important medical concern.

Microascus manginii is a filamentous fungal species in the genus Microascus. It produces both sexual (teleomorph) and asexual (anamorph) reproductive stages known as M. manginii and Scopulariopsis candida, respectively. Several synonyms appear in the literature because of taxonomic revisions and re-isolation of the species by different researchers. M. manginii is saprotrophic and commonly inhabits soil, indoor environments and decaying plant material. It is distinguishable from closely related species by its light colored and heart-shaped ascospores used for sexual reproduction. Scopulariopsis candida has been identified as the cause of some invasive infections, often in immunocompromised hosts, but is not considered a common human pathogen. There is concern about amphotericin B resistance in S. candida.

Chaetomium perlucidum is a neurotropic dematiaceous fungus that is naturally found in the soil, including in agricultural soil, and in the stems of dead plants. The fungus can also be found on the feathers of birds, manure, seeds, and even paper. It is able to thrive at temperatures of 35 and 42 °C.

Lichtheimia ramosa is a saprotrophic zygomycete, typically found in soil or dead plant material. It is a thermotolerant fungus that has also been known to act as an opportunistic pathogen–infecting both humans and animals.

References

  1. 1 2 3 4 Vega W; Orellana M; Zaror L; Gené J; Guarro J. (2006). "Saksenaea vasiformis infections: case report and literature review". Mycopathologia. 162 (4): 289–94. doi:10.1007/s11046-006-0061-6. PMID   17039275. S2CID   4672160.
  2. ↑ Padmaja IJ; Ramani TV; Kalyani S. (2006). "Cutaneous zygomycosis: necrotising fascitis due to Saksenaea vasiformis". Indian Journal of Medical Microbiology. 24 (1): 58–60. doi: 10.1016/S0255-0857(21)02474-9 . hdl: 1807/7251 . PMID   16505559.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 Ribes, J. A.; Vanover-Sams, C. L.; Baker, D. J. (1 April 2000). "Zygomycetes in human disease". Clinical Microbiology Reviews. 13 (2): 236–301. doi:10.1128/CMR.13.2.236. PMC   100153 . PMID   10756000.
  4. 1 2 3 4 5 6 7 8 9 10 Kaushik, Robin; Chander, Jagdish; Gupta, Sanjay; Sharma, Rajeev; Punia, Rajpal Singh (1 April 2012). "Fatal Primary Cutaneous Zygomycosis Caused by Saksenaea vasiformis: Case report and review of literature". Surgical Infections. 13 (2): 125–129. doi:10.1089/sur.2010.078. PMID   22280152.
  5. ↑ Bashford, C; Yin, T; Pack, J (February 2002). "Necrotizing fasciitis: a model nursing care plan". Medsurg Nursing. 11 (1): 37–42, quiz 43. PMID   11901612.
  6. 1 2 3 4 5 Saksena, SB (1953). "A New Genus of the Mucorales". Mycologia. 45 (3): 426–436. doi:10.1080/00275514.1953.12024280. JSTOR   4547711.
  7. 1 2 3 Chakrabarti, A.; Kumar, P.; Padhye, A. A.; Chatha, L.; Singh, S. K.; Das, A.; Wig, J. D.; Kataria, R. N. (1 April 1997). "Primary Cutaneous Zygomycosis Due to Saksenaea vasiformis and Apophysomyces elegans". Clinical Infectious Diseases. 24 (4): 580–582. doi: 10.1093/clind/24.4.580 . PMID   9145731.
  8. 1 2 3 Alvarez, E.; Garcia-Hermoso, D.; Sutton, D. A.; Cano, J. F.; Stchigel, A. M.; Hoinard, D.; Fothergill, A. W.; Rinaldi, M. G.; Dromer, F.; Guarro, J. (6 October 2010). "Molecular Phylogeny and Proposal of Two New Species of the Emerging Pathogenic Fungus Saksenaea". Journal of Clinical Microbiology. 48 (12): 4410–4416. doi:10.1128/JCM.01646-10. PMC   3008438 . PMID   20926710.
  9. ↑ Robeck, T. R; Dalton, L. M (2002). "Saksenaea vasiformis and Apophysomyces elegans Zygomycotic Infections in Bottlenose Dolphins (Tursiops truncatus), a Killer Whale (Orcinus orca), and Pacific White-Sided Dolphins (Lagenorhynchus obliquidens)". Journal of Zoo and Wildlife Medicine. 33 (4): 356–366. doi:10.1638/1042-7260(2002)033[0356:SVAAEZ]2.0.CO;2. PMID   12564534. S2CID   29488757.
  10. ↑ Ellis, J. J; Ajello, L (1982). "An Unusual Source for Apophysomyces elegans and a Method for Stimulating Sporulation of Saksenaea vasiformis". Mycologia. 74 (1): 144–145. doi:10.2307/3792640. JSTOR   3792640.
  11. ↑ Adam, R. D.; Hunter, G.; DiTomasso, J.; Comerci, G. (1 July 1994). "Mucormycosis: Emerging Prominence of Cutaneous Infections". Clinical Infectious Diseases. 19 (1): 67–76. doi:10.1093/clinids/19.1.67. PMID   7948560.
  12. ↑ Ajello, Libero; Dean, David F; Irwin, Richard S (1976). "The Zygomycete Saksenaea vasiformis as a Pathogen of Humans with a Critical Review of the Etiology of Zygomycosis". Mycologia. 68 (1): 52–62. doi:10.2307/3758897. JSTOR   3758897. PMID   945456.
  13. ↑ Pritchard, RC; Muir, DB; Archer, KH; Beith, JM (1–15 Dec 1986). "Subcutaneous zygomycosis due to Saksenaea vasiformis in an infant". The Medical Journal of Australia. 145 (11–12): 630–1. doi:10.5694/j.1326-5377.1986.tb139516.x. PMID   3796372.
  14. 1 2 Torell, J; Cooper, BH; Helgeson, NG (July 1981). "Disseminated Saksenaea vasiformis infection". American Journal of Clinical Pathology. 76 (1): 116–21. doi:10.1093/ajcp/76.1.116. PMID   6942651.
  15. ↑ Lye, GR; Wood, G; Nimmo, G (November 1996). "Subcutaneous zygomycosis due to Saksenaea vasiformis: rapid isolate identification using a modified sporulation technique". Pathology. 28 (4): 364–5. doi:10.1080/00313029600169364. PMID   9007959. S2CID   22179099.
  16. ↑ Padhye, A.A.; Koshi, G.; Anandi, V.; Ponniah, J.; Sitaram, V.; Jacob, M.; Mathai, R.; Ajello, L.; Chandler, F.W. (February 1988). "First case of subcutaneous zygomycosis caused by Saksenaea vasiformis in India". Diagnostic Microbiology and Infectious Disease. 9 (2): 69–77. doi:10.1016/0732-8893(88)90099-5. PMID   3289825.
  17. ↑ Bearer, EA; Nelson, PR; Chowers, MY; Davis, CE (July 1994). "Cutaneous zygomycosis caused by Saksenaea vasiformis in a diabetic patient". Journal of Clinical Microbiology. 32 (7): 1823–4. doi:10.1128/jcm.32.7.1823-1824.1994. PMC   263809 . PMID   7929783.
  18. ↑ HILL, BD; BLACK, PF; KELLY, M; MUIR, D; DONALD, WAJ MC (1 July 1992). "Bovine cranial zygomycosis caused by Saksenaea vasiformis". Australian Veterinary Journal. 69 (7): 173–174. doi:10.1111/j.1751-0813.1992.tb07509.x. PMID   1445086.
  19. ↑ Salas, Valentina; Pastor, F. Javier; Calvo, Enrique; Sutton, Deanna; García-Hermoso, Dea; Mayayo, Emilio; Dromer, Françoise; Fothergill, Anette; Alvarez, Eduardo; Guarro, Josep (1 October 2012). "Experimental murine model of disseminated infection by Saksenaea vasiformis: successful treatment with posaconazole". Medical Mycology. 50 (7): 710–715. doi: 10.3109/13693786.2012.673137 . PMID   22458251.
  20. ↑ Prabhu, R. M.; Patel, R. (March 2004). "Mucormycosis and entomophthoramycosis: a review of the clinical manifestations, diagnosis and treatment". Clinical Microbiology and Infection. 10 (s1): 31–47. doi: 10.1111/j.1470-9465.2004.00843.x . PMID   14748801.
  21. ↑ Spellberg, B.; Edwards, J.; Ibrahim, A. (14 July 2005). "Novel Perspectives on Mucormycosis: Pathophysiology, Presentation, and Management". Clinical Microbiology Reviews. 18 (3): 556–569. doi:10.1128/CMR.18.3.556-569.2005. PMC   1195964 . PMID   16020690.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.