Prototheca wickerhamii

Prototheca wickerhamii ( Gram stain ) from the blood of a 79 - year-old man with sepsis

Prototheca wickerhamii is a ubiquitous green alga that has no chlorophyll. It is widespread in the normal environment and can in humans in rare cases, a disease that trigger Protothekose which usually manifests itself in the form of skin lesions. The species was first described in 1959.

Biology

P. wickerhamii is a unicellular alga from spherical to elliptical in shape and 3 to 10 microns in diameter. The thick-walled cell ( theca ) has a cell wall with two distinct layers by electron microscopy and contains 2 to 20 symmetrical, mulberry- like arrangement of endospores. Reproduction is asexual by destroying the mother cell and release the spores, which develop into new adult cells. The spore release occurs under ideal conditions every 5 to 6 hours.

P. wickerhamii has neither chloroplasts nor chlorophyll. The algae may therefore not photosynthesize, but lives heterotrophic.

Identification

The occurrence of P. wickerhamii as pathogens can be studied by the culture of infected fluid in Sabouraud dextrose agar or by microscopic examination of tissue samples on sporangia.

Antimicrobial therapy

The treatment of infections with P. wickerhamii is not standardized. Amphotericin B, itraconazole, posaconazole, and voriconazole were used.