Clinical Mycology &Actinomycetes

The objective• Discuss the difference between

Eukaryotic and prokaryotic organisms.

• Differentiate between different groups of fungi.

• Microscopic examination of unicellular, multicelluar fungi and actinomycetes.

• FUNGI are eukaryotic organisms (is any organism whose cells contain a nucleus and other structures (organelles) enclosed within membrane).

• yeast

• MOLDS

• Fleshy fungi

• The study of Fungi is termed Mycology.

• The Diseases caused by fungi are called Mycotic diseases or mycosis.

• In general , fungi are beneficial, while some fungi can cause damage.

Yeasts• Unicellular oval or spherical fungi.• Increased in number asexually by a process termed

budding

• Yeast are facultative anaerobes : Respire aerobically if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent.

• The vast majority of yeasts are nonpathogenic and some have a great value in industrial fermentaion such as Saccharomyces Sp. are used for both baking and brewing.

• Because of their unicellular and microscopic nature, yeast colonies appear similar to bacterial colonies on solid media.

• The yeast Candida is normal flora of the gastrointestinal tract and is also found on the skin and on the mucous membrane of the mouth and vagina.

• Candida may become an Opportunistic pathogen (those that take advantage of certain situations).

• The most common Candida sp. Causing human infections is C. albicans ( 50-60% ) C. glabrata is second (15-20%) C. parapsilosis ( 10-20%)

Actinomycetes:

• Actinomycetes are a specific group as bacteria. Morphologically they resemble fungi because of their elongated cells that branch into filaments or hyphae.

• During the process of composting mainly thermophilic (adapted to high temperatures) and thermotolerant actinomycetes are responsible for decomposition of the organic matter at elevated temperatures. In the initial phase of composting the intensive increase of microbial activity leads to a self heating of the organic material. High temperatures in composting help to kill viruses, pathogenic bacteria.

Actinomycetes:

• Actinomycetes live predominantly aerobically, i.e. they need oxygen for their metabolism. The compost material should therefore be well aerated.

• Generally, actinomycetes grow on fresh substrates more slowly than other bacteria and fungi. During the composting process the actinomycetes degrade natural substances such as chitin or cellulose.

• Natural habitats of thermophilic actinomycetes are silos, corn mills, air conditioning systems.

• actinomycetes are found to be responsible for allergic symptoms in the respiratory tract (e.g. "extrinsic allergic alveolitis", EAA).