Introduction of mycoses
dr Ance Roslina,M.Kes
FK-UMSU
2021
Structure fungi
• Fungi are eukaryotic organisms that do not contain
chlorophyll
• have cell walls; chitin, glucan, mannan
• filamentous structures; uni and multi
• produce spores.
• These organisms grow as saprophytes and decompose dead
organic matter.
• There are between 100,000 to 200,000 species depending on
how they are classified.
• About 300 species are presently known to be pathogenic for
man.
Classification fungi
• Phylum Zygomycota
• Phylum Ascomycota
• Phyum Basidiomycota
• Deuteromycota; Imperfect fungi
MORPHOLOGY
Pathogenic fungi can exist as:
1. Yeasts/khamir
2. Mushroom/Cendawan
3. Mold/kapang
Yeast
▪ A yeast can be defined
morphologically as a cell that
reproduces by budding or by
fission
▪ In which a progenitor or
“mother” cell pinches off a
portion of itself to produce a
progeny or “daughter” cell.
▪ The daughter cells may
elongate to form sausage-like
pseudohyphae.
▪ Yeasts are usually unicellular
and produce round, pasty, or
mucoid colonies on agar.
Mold:
– Molds, on the other hand, are multicellular organisms consisting of
threadlike tubular structures, called hyphae which elongate at their tips
by a process known as apical extension.
– Hyphae are either coenocytic (hollow and multinucleate) or septate
(divided by partitions or cross-walls).
– The hyphae form together to produce a matlike structure called a
mycelium.
Mold
- The colonies formed by molds are often described as
filamentous, hairy, or woolly.
- When growing on agar or other solid surfaces, molds
produce hyphae, termed vegetative hyphae, which
grow on or beneath the surface of he culture
medium, and hyphae that project above the surface
of the medium (aerial hyphae)
Dimorphic fungi
The dimorphic fungi have two forms
• 1. YEAST (ragi) - (parasitic or pathogenic form).
This is the form usually seen in tissue, in exudates, or if cultured in
an incubator at 37 degrees C.
• 2. MYCELIUM - (saprophytic form).
– The form observed in nature or when cultured at 25 degrees C.
– Conversion to the yeast form appears to be essential for pathogenicity.
– Dimorphic fungi are identified by several morphological or biochemical
characteristics, including the appearance of their fruiting bodies.
– The asexual spores may be large (macroconidia, chlamydospores) or
small (microconidia, blastospores, arthroconidia).
HYPHAE
Reproduction:SEXUAL
Formation Zygospore, ascospores, basidiospores
Zygomycota
• Hifa: septate , non septate
• Sexual: zygospore
• Asexual spora
• Ex: Rhizopus, mucor
Asexual spore
Ascomycota
• Sexual: ascospore
• Asexual: budding,
conidia
• saccharomyces
basidiomycota
• Asexual: conidia
• Sexual; basidiospora
Mediccaly important fungi
Reproduction
Factors predisposing to fungal infections:
▪ Prolonged antibiotic ▪ Indwelling catheters
therapy
▪ Obesity
▪ Underlying disease (HIV
infection, cancer, diabetes, ▪ Drug addiction
etc.) ▪ Transplants
▪ Age ▪ Occupation
▪ Surgical procedures
▪ Immunosuppressive drugs
▪ Irradiation therapy
Fungal Pathogenicity (virulence factors):
• Ability to adhere to host cells by way of cell wall glycoproteins
• Production capsules allowing them to resist phagocytosis
• Production of a cytokine called GM-CSF by Candida albicans that suppress
the production of complement.
• Ability to acquire iron from red blood cells as in Candida albicans
• Ability to damage host by secreting enzymes such as keratinase, elastase,
collagenase
• Ability to resist killing by phagocytes as in dimorphic fungi
• Ability to secrete mycotoxins
• Having a unique enzymatic capacity
• Exhibiting thermal dimorphism
• Ability to block the cell-mediated immune defences of the host.
• Surface hydrophobicity
Host defence factors:
▪ Physical barriers, such as ▪ Chemical barriers, such as
skin and mucus membranes secretions, serum
▪ The fatty acid content of the factorsMost fungi are
skin mesophilic and cannot grow
▪ The pH of the skin, mucosal at 37C.
surfaces and body fluids ▪ Natural Effector Cells
▪ Epithelial cell turnover (polymorphonuclear
leucocytes) and the
▪ Normal flora Professional Phagocytes
(monocytes and
macrophages)
Immunity to fungal infections:
▪ Mechanism of immunity to fungal infections can be
innate or acquired.
▪ The non-specific immunity includes the physical barriers
offered by skin and mucus membranes along with their
secretions and normal flora.
▪ The pH, body temperature and serum factors along with
phagocytic cells play an important part in providing non-
specific immunity.
▪ Even though body mounts both humoral and cell
mediated immunity, it is the latter that is the mainstay of
• host defence
• TERIMA KASIH
