IDENTIFICATION
Genus Species
EX: Histoplasma capsulatum Aspergillus niger
Candida albicans
Histoplasma capsulatum
Kingdom :Mycetae
Division :Mycota
Subdivision :Eumycota
Class :Deuteromycetes
Order :Moniliales
Family :Moniliaceae
Genus :Histoplasma
Species :Histoplasma capsulatum
Aspergillus niger
Kingdom :Mycetae
Division :Ascomycota
Subdivision :Ascomycota
Class :Ascomycetes
Order :Aspergillales
Family :Aspergillaceae
Genus :Aspergillus
Species :Aspergillus niger
Candida albicans
Kingdom :Mycetae
Division :Deuteromycota
Subdivision :Deuteromycotina
Class :Blastomycetes
Order :Saccharomycetales
Family :Saccharomycetaceae
Genus :Candida
Species :Candida albicans
General Features of
Fungi
General Features of Fungi
• Fungi are pests to eukaryotic cells and thus are insensitive to many bacterial antibiotics.
• They are not photosynthetic and are immobile.
• They can grow in more acidic mediums when the optimum pH is 6.0.
• Compulsory aerobes, optimum reproduction temperatures are 20-30
°C.
• Pathogenic fungi that cause systemic mucosal can poison at 37 °C.
• Fungi usually grow slowly in the medium, Zygomycetes and
Aspergillus species can grow in 2-3 days, but most dermatophyte incubation period is 3-5 weeks.
• Fungi can be classified in 2 groups as mold and yeast.
MOULD
• The molds are in filamentous form and are in the form of branched filaments and hyphae of 2-10 μm in diameter.
• In many species of fungi, hyphae show segmented structure called septum, but Zygomycetes are septum-free.
• The branched hyphae form complex structures like arabic hair that are given mycelium name.
• Fungi form large feathered columns on the nutrient, which
synthesize aerial budding hyphae bearing asexual spores.
YEAST
• Yeast, oval, spherical or shuttle-like cells are 3-5 μm in diameter and form colonies on the surface of the nutrient different from bacteria and large.
• Yeast are single-cell organisms that reproduce by budding or spore formation alone.
• Some fungal pathogens are dimorphic, producing yeast or yeast-like growth in animal tissues (in vivo) and in enriched media (in vitro) when grown at 37 ° C, producing fungi-like growth in their natural
environment and at temperatures incubated at 25 ° C.
• Like Candida albicans, yeasts are seen as a separate hyphal-like shuttle, called pseudohypha, adhered to each other in animal tissues.
• Pathogenic fungi can be found in yeast or in mycelial form.
• Some fungi can be seen in both yeast and mycelial forms. Such fungi are called "dimorphic fungi".
• 1. YEAST - (parasitic or pathogenic form): It occurs in cultures that are incised in these tissue sections, in some exudates or at 37C.
• 2. MISSELIUM / FUNGI - (saprophytic or mold morph): This is the form seen when they are cultured in nature or at 25C.
• Yeast transformation in dimorphic fungi is a necessary feature for pathogenicity.
