| Prototheca cutis | |
|---|---|
Scientific classification 
| |
| Kingdom: | Plantae |
| Division: | Chlorophyta |
| Class: | Trebouxiophyceae |
| Order: | Chlorellales |
| Family: | Chlorellaceae |
| Genus: | Prototheca |
| Species: | P. cutis
|
| Binomial name | |
| Prototheca cutis Satoh et al., 2010
| |
Prototheca cutis is a species of achlorophyllic green alga in the genus Prototheca. It is an opportunistic pathogen that causes cutaneous infections in humans and has also been reported in animals. The species was first described in 2010 after its isolation from chronic dermatitis in an immunosuppressed patient in Japan.12
Description
Prototheca cutis is a non-photosynthetic (achlorophyllic) green alga that forms white to ivory, smooth colonies on Sabouraud dextrose agar.1 Vegetative cells are ovoid and measure 2-8 μm in diameter. Reproduction occurs through formation of sporangia containing endospores, a characteristic feature of the genus.31
The species grows optimally at 28-30 °C, exhibits weak growth at 37 °C, and does not grow at 40 °C.1
Disease
Humans
The species was originally described from a case of ulcerative cellulitis-like dermatitis in an immunosuppressed patient receiving corticosteroid therapy for psoriasis. The infection remained localized to the skin and improved following prolonged itraconazole therapy.1 Human disease appears to be rare, and P. cutis is considered an opportunistic pathogen causing cutaneous protothecosis. Because commercial identification systems may incorrectly identify the organism as P. wickerhamii, its true incidence is uncertain.1
Animals
In 2021, P. cutis was reported as the cause of severe nasal protothecosis in an 11 year old domestic cat in the United States.4 The cat developed progressive rhinitis with destructive pyogranulomatous inflammation affecting the nasal planum and turbinates.
References
References
- Satoh, Kazuo; Ooe, Kenji; Nagayama, Hirotoshi; Makimura, Koichi (2010). "Prototheca cutis sp. nov., a newly discovered pathogen of protothecosis isolated from inflamed human skin". International Journal of Systematic and Evolutionary Microbiology. 60 (Pt 5): 1236–1240. doi:10.1099/ijs.0.016402-0. ISSN 1466-5026. PMID 19666796.
- Dell'Amore, Christine (2010-05-25). "Toxic New Algae Species Discovered". National Geographic. Retrieved 2026-06-30.
- Walsh, Thomas J.; Hayden, Randall T.; Larone, Davise Honig (2018). Larone's medically important fungi: a guide to identification (6th ed.). Washington, District of Columbia: ASM press. ISBN 978-1-55581-988-0.
- Maboni, Grazieli; Elbert, Jessica A.; Stilwell, Justin M.; Sanchez, Susan (2021). "Genomic and Pathologic Findings for Prototheca cutis Infection in Cat". Emerging Infectious Diseases. 27 (3): 979–982. doi:10.3201/eid2703.202941. ISSN 1080-6059. PMC 7920651. PMID 33622485.