Sarocladium kiliense is a saprobic fungus that is occasionally encountered as a opportunistic pathogen of humans, particularly immunocompromised and individuals. The fungus is frequently found in soil and has been linked with skin and systemic infections. This species is also known to cause disease in the green alga, Cladophora glomerata as well as various fruit and vegetable crops grown in warmer climates.
History and taxonomy
Sarocladium kiliense was renamed from Acremonium kiliense by Grütz in 1925, and it is particularly known as Cephalosporium acremonium in medical mycology. The name Cephalosporium was used to describe colorless molds with simple unbranched conidiophores and condiogenous cells bearing at the tip or head of the unicellular conidia. For all such molds that had these characteristics, many authors have been using the name C. acremonium. However, in 1971, Walter Gams kept the name A. kiliense to describe the fungus that were frequently found in soil and were associated with skin infections. Other similar fungus were put to a new species called A. strictum.
Gams divided Acremonium into three major sections: Acremonium, Gliomastix, and Nectriodea. Acremonium comprises four major clades: A. sclerotigenum, Sarocladium, A. curvulum, and A. breve. The genus Sarocladium contains multiple species previously treated in Acremonium and those that belong to the A. strictum and A. bacillisporum clades. Sarocladium species are noted for melanogenesis, a pathogenic factor in fungal disease, which is seen in S. kiliense.
Morphology
Colonies of S. kiliense have distinct characteristics, such as its colour, when grown on different medium. When the colonies are grown on glucose peptone agar at a temperature of , colonies can reach a diameter of 50 mm in one week. The colonies have a flat topography with a grey to an orange coloration. At the microscopic level, predominant features include balls of ellipsoidal conidia accumulated at the ends of long slender phialides and have oval chlamydospores. The conidiophores are long, straight, slightly tapering phialides, arising as side-branches on hyphae. At the end of the phialides are accumulated balls of slimy conidia with an ellipsoidall shape measuring 3-6 x 1.5 mm.
Colonies that are grown on sabouraud dextrose agar have a white coloration that later becomes pink during further incubation. Microscopically, the growth mostly has fasciculate mycelium giving rise to slender phialides. When the colonies are grown on oatmeal agar at a temperature of for 10 days, the isolates form poorly differentiated phialides, and single-cells, thick-walled uncoloured chlamydospores with chromophilic walls measuring 4-8 μm in diameter on the ends of hyphae and intervening in filaments. After 7 days of incubation, the chlamydospores become apparent although sclerotia remain absent.
Ecology and growth conditions
Sarocladium kiliense is a fungus that can be found throughout the world and have been seen in various European countries and warmer countries such as Egypt, India, and Nigeria. It is commonly isolated from the soil and seen in cereal fields, hay, apples, endosperm of rye grains, tomatoes, ground nuts, pineapples, and the soils of grass lands. In addition, Sarocladium kiliense have also been found to be an aerial contaminant. Isolates that are grown at higher temperatures have larger colonies than isolates grown at lower temperatures. When colonies are grown on glucose peptone agar at a temperature of , colonies can reach a diameter of 50 mm in one week. Colonies that are grown at on malt extract agar (MEA) form smaller colonies measuring 1.8-2.3 cm in diameter.