Mycotic fungal infections

1. FUNGAL INFECTIONS

2. SIGNIFICANCE OF PARASITIC
INFECTIONS
•Parasitic infections are a major problem
worldwide.
•More than 500 million people are
infected with malaria.
•More than 2 million (mostly children)
die each year from malaria.
•Entamoeba are intestinal parasites that
infect 10% of the world population.
•Trypanosoma parasites infect 16 million
people in Latin America each year.

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 these 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
(coenocytic)
• Yeasts are unicellular
• One major difference is that most fungi have cell
walls that contain chitin, unlike the cell walls of
plants, which contain cellulose

5. YEASTS AND MOLDS
• Molds - multicellular
• Yeasts - unicellular
• The simplest form of growth is budding.
• Buds are called blastoconidia.
• Seen in yeasts.

6. ..Reproduction in yeast

7. Classification of Fungi
Oomycetes
Zygomycetes
Ascomycetes
Basidiomycetes
Deuteromycetes

8. CLASSIFICATION OF PATHOGENIC
FUNGI
•Fungal diseases are classified into 4 groups:
•Superficial mycoses
•Mucocutaneous mycoses
•Subcutaneous mycoses
•Deep mycoses

9. SUPERFICIAL MYCOSES
• The fungi invade only the dead, cornified
layers of the skin, nails and hair. Most of the
resulting pathology is caused by the host's
reaction to the infecting fungus.The fungus
alone has only a minimal capacity to damage
skin directly.
Piedra – colonization of the hair shaft causing
black or white nodules
• Tinea nigra – brown or black superficial skin
lesions
• Tinea capitis – folliculitis on the scalp and
eyebrows

10. 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.

11. PATHOLOGY
• The fundamental pathogenic mechanisms of
dermatophytosis involve two distinct phases:
• 1. Colonization
• infected with a fungal spore and invasion begins
• within the stratum corneum
• The downward extension of these hyphae is restricted
• Lateral expansion continues for 10-35 days
• 2. Host-parasite interaction
• The first detectable immune response is cell-mediated immunity
(CMI)
• intense inflammatory process
• Epidermal integrity is breached; oozing and weeping of the
tissue fluid occur. Invasion of hair follicles results in inflamed
nodules, deep seated pustules, and abscesses.

12. CUTANEOUS AND
MUCOCUTANEOUS MYCOSES
Cutaneous mycosis is a group of superficial
fungal infections of the skin, hair or nails. No
living tissue is invaded, however a variety of
pathological changes occur in the host because
of the presence of the infectious agent and its
metabolic products.
Associated with:
• Skin
• Eyes
• Sinuses
• Oropharynx and external ears

13. CUTANEOUS AND
MUCOCUTANEOUS MYCOSES
Ringworm – skin lesions characterized by red margins, scales and
itching:
Classified based on location of infection
• Tinea pedis – on the feet or between the toes
• Tinea corporis – between the fingers, in wrinkles on the
palms
• Tinea cruses – lesions on the hairy skin around the genitalia
• Tinea capitis – scalp and eyebrows
Onychomycosis – chronic infection of the nail bed
• Commonly seen in toes
Hyperkeratosis – extended scaly areas on the hands and feet

14. Microbiology: A Clinical Approach © Garland Science
CUTANEOUS AND
MUCOCUTANEOUS MYCOSES
www.doctorfungus.org

15. • 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
• An indicator of immunodeficiency.

16. SUBCUTANEOUS MYCOSES
•Localized primary infections of
subcutaneous tissue:
•Can cause the development of cysts and
granulomas.
•Provoke an innate immune response -
eosinophilia.

17. There are several types:
• Sporotrichosis – traumatic implantation of fungal
organisms
• Paranasal conidiobolae mycoses – infection of the
paranasal sinuses
• Causes the formation of granulomas.
• Zygomatic rhinitis – fungus invades tissue through
arteries
• Causes thrombosis
• Can involve the CNS.

18. DEEP MYCOSES
• Deep mycoses Usually seen in immunosuppressed patients
with:
• AIDS
• Cancer
• Diabetes
• 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

19. DEEP MYCOSES
• Coccidiomycoses – caused by genus Coccidioides
• Primary respiratory infection
• Leads to fever, erythremia, and bronchial
pneumonia
• Usually resolves spontaneously due to immune
defense
• Some cases are fatal

20. DEEP MYCOSES
• Histoplasmosis – caused by Histoplasma
capsulatum
• Often associated with immunodeficiency
• Causes the formation of granulomas
• If disseminated, histoplasmosis can be fatal.

21. Microbiology: A Clinical Approach © Garland Science
DEEP MYCOSES
© CDC/Susan Lindsley, VD

22. • 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.

23. Common Fungal Diseases
• Candidiasis
• Dermatomycoses
• Respiratory Fungal Infections

24. 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
• Vulvovaginitis
• Oral candidiasis (thrush)
• Intestinal candidiasis

25. 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.

26. Dermatomycoses
• Tinea is a fungus that can grow on your skin, hair or nails.
• As it grows, it spreads out in a circle, leaving normal-
looking skin in the middle- look like a ring.
• At the edge of the ring, the skin is lifted up by the
irritation and looks red and scaly.
• To some people, the infection looks like a worm is under
the skin.
• Because of the way it looks, tinea infection is often called
"ringworm." no worm under the skin!!

27. Respiratory Fungal Infections
Cryptococcosis
•Cryptococcus neoformans
•A yeast of class Basidiomycetes
•Soil; esp. contaminated with bird
droppings
•Airborne to humans
•Gelatinous capsules resist phagocytosis
•Respiratory tract infections
•Occasional systemic infections involving
brain & meninges

28. Respiratory Fungal Infections
Histoplasmosis
•Histoplasma capsulatum, an ascomycete
•Airborne infection
•Transmitted by inhalation of spores in
contaminated spores
•Associated with chicken & bat droppings
•Respiratory tract symptoms; fever,
headache, cough, chest pains

29. Respiratory Fungal Infections
Blastomycosis:
• Blastomyces dermatitidis, an ascomycete
• Associated with dusty soil & bird
droppings
• Skin transmission: via cuts & abrasions
• Raised, wart-like lesions
• Airborne transmission: via inhalation of
spores
• Respiratory tract symptoms
• Occasional internal infections with high
fatality rate

30. Prevention
who is at risk of getting a fungal infection:
• People taking long-term antibiotics or immunosuppressant
drugs
• People who perspire heavily
• Individuals who work or spend time in an environment where
they come in contact with people who are at high risk, such
as nurses, school teachers, hospitalized patients, students
and coaches
Recognize what areas of your skin are at risk of a fungal
infection:
• Parts of your skin that are moist are more at risk for fungal
infections since the fungus needs moisture to thrive

31. Prevention
Take care in public places:
• Try to reduce your exposure to public areas where other
people with fungal infections may have been
Keep your skin clean and dry

32. Treatment
• Products that contain miconazole, clotrimazole,
terbinafine or tolnaftate can treat athlete foot & ring
worm
• Concern your doctor if you have diabetes because
diabetes or a depressed immune system can increase
your risk of experiencing more severe symptoms from a
fungal infection.