2. General Characters
These organisms are classified as
a kingdom, Fungi, which is separate
from plants, animals, protists and bacteria
One major difference is that fungal cells
have cell walls that contain chitin, contain
cellulose (cellulase enzymes)
3. FUNGAL INFECTIONS
• The study of fungi is known as mycology and
scientist who study fungi is known is a
mycologist
• A fungus is a member of a large group of
eukaryotic organisms
• Microorganisms such as yeasts and molds, as well
as the more familiar mushrooms
• Over 60,000 species of fungi are known
• Fungi are important for the environment.
• They are normally harmless to humans
• Fungi can be opportunistic pathogens.
4. Structure
• The main body of most fungi is made up of fine,
branching, usually colourless threads called
hyphae
• Several of these t hyphae, all intertwining to make
up a tangled web called the mycelium
• Most fungi are multinucleate and multicellular
organisms with cross wall called septa or
aseptate
• Yeasts are unicellular
5.
6. 1- General Characters
•Eukaryotic Organisms (i.e true nucleus)
•Non-Vascular Organisms
•Non-motile except few fungi
•Vegetative body may be:
unicellular Filamentous
Septated Non-Septated
9. YEASTS AND MOLDS
•Molds - multicellular
•Yeasts - unicellular
•The simplest form of growth is budding.
•Buds are called blastoconidia.
•Seen in yeasts.
10. …..Classification of Fungi
1-Zygomycetes
• Unenclosed zygospores produced at ends of
hyphae
• Example: Black bread mold Rhizopus
2-Ascomycetes
• Ascospores are enclosed in asci (sac-like
structures) at the ends of hyphae or yeasts
• Examples: Penicillium, Saccharomyces
12. …..Classification of Fungi
3-Basidiomycetes
• Basidiospores are produced on a club-shaped
structure called a basidium
• Example: Mushrooms, Cryptococcus
4-Deuteromycetes
• “Imperfect fungi”
• No sexual stage is known for these fungi
• Many parasitic fungi fall into this class
• Examples: Candida, Epidermophyton
13.
14. Economic Importance
Harmful
•Cause human,animal, plant
disease directly or their toxins
•Cause rot of food
•Can destroy manufactured
good
Useful
•Yeast bread & brew
•Antibiotics penicillin
•Steroids and Hormons
•Stinky Cheeses
•Source of organic compost
•Source of food
to
15.
16. CLASSIFICATION OF
PATHOGENIC FUNGI
according to the site of infection
Only 100 species are pathogenic to human
Fungal diseases are classified into 4 groups:
•Superficial mycoses
•Mucocutaneous mycoses
•Subcutaneous mycoses
•Deep mycoses
17. SUPERFICIAL MYCOSES
Fungal infections that do not involve a tissue
response:
– colonization of the hair shaft causing black
or white nodules
– brown or black superficial skin lesions
•– folliculitis on the scalp and eyebrows
18. …SUPERFICIAL MYCOSES
•Favus – destruction of the hair follicle.
•Pityriasis – dermatitis characterized by
redness of the skin and itching:
•Caused by hypersensitivity reactions to
fungi normally found on skin
•Mostly seen in immunocompromised
patients.
19.
20.
21.
22. …CUTANEOUS AND
MUCOCUTANEOUS MYCOSES
Ringworm – skin lesions characterized by red margins,
scales and itching:
•Classified based on location of infection
– on the feet or between the toes
– between the fingers, in wrinkles on the palms
lesions on the hairy skin around the genitalia
– scalp and eyebrows
23. Dermatomycoses
• Dermatomycoses are any fungal infection of
the skin or hair.
• Caused by many different species and are
generally named after the infected area
rather than the species that causes it.
• Dermatomycoses are one of the most
frequent sources of lesions on the skin.
24. …Dermatomycoses
Cause: Several genera of dermatophytic
fungi
– Trichophyton,
– Microsporum,
– Epidermophyton,
– Grow on skin, hair, nails
– Transmitted by contact with infected persons
or animals
39. Candidiasis
Cause: Candida albicans
– Dimorphic fungus of the class
Deuteromycetes
– Grows as yeast or pseudohyphae
– Spread by contact; often part of normal flora
– Opportunistic infections common
– Vulvo-vaginitis
– Oral candidiasis (thrush)
– Intestinal candidiasis
43. …CUTANEOUS AND
MUCOCUTANEOUS MYCOSES
•Mucocutaneous candidiasis – colonization of the
mucous membranes
•Caused by the yeast Candida albicans
•Often associated with a loss of immunocompetence
•Thrush – fungal growth in the oral cavity
•Vulvovaginitis – fungal growth in the vaginal canal
•Can be associated with a hormonal imbalance
47. DEEP MYCOSES
Deep mycoses Usually seen in immunosuppressed
patients with:
•AIDS
•Cancer
•Un controlled Diabetes Type 1 (Insuline dependent)
•Can be acquired by:
•Inhalation of fungi or fungal spores
•Use of contaminated medical equipment
•Deep mycoses can cause a systemic infection –
disseminated mycoses
•Can spread to the skin
48. ..DEEP MYCOSES
Coccidiomycoses – caused by genus Coccidioides
•Primary respiratory infection
•Leads to fever, bronchial pneumonia
•Usually resolves spontaneously due to immune
defense
•Some cases are fatal
49. …DEEP MYCOSES
Histoplasmosis – caused by Histoplasma capsulatum
•Often associated with immunodeficiency
•Causes the formation of granulomas
•Can necrotize and become calcified
•If disseminated, histoplasmosis can be fatal.
50. …DEEP MYCOSES
Aspergillosis – caused by several species of Aspergillus
•Associated with immunodeficiency
•Can be invasive and disseminate to the blood and
lungs
•Causes acute pneumonia
•Mortality is very high.
•Death can occur in a matter of weeks.
