The document provides an overview of medical mycology and fungal infections. It discusses different types of fungal infections including superficial mycoses that do not involve tissue response, cutaneous mycoses caused by dermatophytes that infect the skin, subcutaneous mycoses caused by soil fungi, and systemic or opportunistic mycoses that affect immunocompromised individuals. Common fungal infections like candidiasis, aspergillosis, cryptococcosis and zygomycosis are explained in terms of their causative agents and presentations. The diagnosis and treatment of various mycoses is also covered briefly.

1. Medical
Mycology
Introduction
to
Basics
for Clinical officers
WALTER WASWA,
BSC.MLS
6/21/2017 WALTER WASWA 1

2. Reference books
• Brooks, Geo. F. etal, (2007):Medical
microbiology, 24ed. The McGraw-Hill
Companies, Inc. New York.-----an e book in the
library.
• Other books on microbiology in the library.
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3. Fungal Infections/ Mycoses
1. SUPERFICIAL
2. CUTANEOUS MYCOSES
3. SUBCUTANEOUS MYCOSES
4. SYSTEMIC
5. OPPORTUNISTIC
6. FUNGAL TOXINS AND ALLERGIES
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4. SUPERFICIAL MYCOSES
Fungal infections that do not involve a tissue
response:

5. …SUPERFICIAL MYCOSES
•Pityriasis Versicolor. chronic mild superficial
infection of the stratum corneum caused by
Malassezia globosa,
•M restricta,
•M furfur complex.
• Invasion of the cornified skin and the host
responses are both minimal.

6. SUPERFICIAL MYCOSES
• Tinea Nigra- is a superficial chronic and
asymptomatic infection of the stratum
corneum caused by the dematiaceous fungus
Hortaea (Exophiala) werneckii
• This condition is more prevalent in warm
coastal regions and among young women.
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7. SUPERFICIAL MYCOSES
• Piedra
• Black piedra is a nodular infection of the hair
shaft caused by Piedraia hortai.
• White piedra, due to infection with
Trichosporon species, presents as larger,
softer, yellowish nodules on the hairs.
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8. CUTANEOUS
•caused by fungi that infect only the
superficial keratinized tissue (skin, hair, and
nails)/cannot grow at 37degrees
•Dermatophytes eg
microsporon/trichophyton/epidermophyton
•Sometimes reffered as Ringworm – skin lesions
characterized by red margins, scales and itching
•Image?

9. …CUTANEOUS MYCOSES
•Classified based on location of infection
a) Tinea pedis – on the feet or between the toes
b) Tinea corporis – between the fingers, in wrinkles
on the palms
c) Tinea cruses – lesions on the hairy skin around
the genitalia
d) Tinea capitis – scalp and eyebrows
e) Onychomycosis – chronic
infection of the nail bed
•Commonly seen in toes
•Hyperkeratosis – extended scaly areas on the hands
and feet

10. Microbiology: A Clinical Approach © Garland Science
..CUTANEOUS
www.doctorfungus.org

11. Mucocutaneous …
•MUCOCUTANEOUS MYCOSES 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.
•Vulvovaginitis – fungal growth in the vaginal
canal
•Can be associated with a hormonal
imbalance

12. SUBCUTANEOUS MYCOSES
•Agent –from the soil /vegetable
•Entry-through trauma
•localized primary infections of
subcutaneous tissue:
•Can cause the development of cysts and
granulomas.
•Provoke an innate immune response -
eosinophilia.

13. SUBCUTANEOUS MYCOSES
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.

14. SUBCUTANEOUS MYCOSES
• At ambient environmental temp-mould
• At 35-37degrees grow as budding yeast
• Sporothrix schenckii -Sporotrichosis
• Phialophora verrucosa, Fonsecaea pedrosoi,
others - Chromoblastomycosis
• Pseudallescheria boydii, Madurella
mycetomatis, others - Mycetoma
• Exophiala, Bipolaris, Exserohilum, and others -
Phaeohyphomycosis
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15. DEEP/systemic 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

16. Common examples
• Coccidioides immitis, C posadasii -
Coccidioidomycosis
• Histoplasma capsulatum- Histoplasmosis
Blastomyces dermatitidis -Blastomycosis
• Paracoccidioides brasiliensis -
Paracoccidioidomycosis
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17. Microbiology: A Clinical Approach © Garland Science
..DEEP MYCOSES
www.doctorfungus.org

18. ..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

19. …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.

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

21. …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.

22. opportunistic mycoses eg.
1. Candida albicans and other Candida species -
Systemic candidiasis
2. Cryptococcus neoformans- Cryptococcosis
3. Aspergillus fumigatus and other Aspergillus
species -Aspergillosis
4. Species of Rhizopus, Absidia, Mucor, and other
zygomycetes - Mucormycosis (zygomycosis)
5. Penicillium marneffei- Penicilliosis

23. 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

24. Candidiasis
Cutaneous
Thrush
Vaginal candidiasis is the most common
clinical infection. Local factors such as pH
and glucose concentration (under
hormonal control) are of prime
importance in the occurrence of vaginal
candidiasis. In mouth: normal saliva
reduces adhesion (lactoferrin is also
protective).

25. Chronic mucocutaneous
candidiasis
Chronic mucocutaneous
candidiasis (CMC) is the label
given to a group of overlapping
syndromes that have in common
a clinical pattern of persistent,
severe, and diffuse cutaneous
candidal infections. These
infections affect the skin, nails
and mucous membranes.
Immunologic studies of patients with
CMC often reveal defects related to
cell-mediated immunity, but the
defects themselves vary widely.

26. Mucutaneous candidiasis: response to
fluconazole
Transfusion of a Candida-specific transfer factor has
been reported to be very successful (remission for > 10
years) when combined with antifungal therapy. The
availability of effective oral agents, especially the azole
antimicotics, has dramatically changed the life of
patients living with CMC.

27. Cryptococcosis
Respiratory Fungal Infection
–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. Opportunistic Mycoses
•Opportunistic mycoses are fungal infections that do not
normally cause disease in healthy people, but do cause
disease in people with weakened immune defenses.
•The most common infections are:
•Candidiasis
•Aspergillosis
•Cryptococcosis
•Zygomycosis
•Pneumocystis carinii

29. Cryptococcus neoformans
• Primary infection in lungs
• Cryptococcal meningitis is most common disseminated
manifestation
• Can spread to skin, bone and prostate
Organism is ubiquitous and infections
occur worldwide
C. neoformans recovered in large
amounts in pigeon poop
Does not cause disease in birds

30. Diagnosis
• Lumbar puncture and microscopic
examination of cerebrospinal fluid
is diagnostic.
• (India ink staining)
Cyrptococcal antigens in CSF and
serum.
Immune response
Phagocytosis by neutrophils is inhibited by the presence of a
capsule.
However, activated neutrophils have an increased capacity to
phagocytize C. neoformans.
Cell mediated immunity primary defense
About 30% of cryptococcus infections occur in patients with
lymphoma (CNS)

31. Aspergillosis
Major portal of entry is the
respiratory tract. Dissemination
can occur from the lungs and
involve other areas of the lung,
the brain, GI tract, and kidney.
CNS and nasal-orbital cavities
can also occur without lung
involvement. Risk factors for
invasive disease are
neutropenia and high doses of
adrenal corticosteroids

32. Aspergillosis
• Aspergillosis is the most common fatal infection seen in patients with chronic
granulomatous disease of childhood.
• Patients with this condition are unable to form toxic oxygen radicals after
phagocytosis.
• Progressive and disseminated disease can complicate neoplastic diseases,
especially acute leukemia, bone marrow and organ transplantation (not
necessarily AIDS).
In immunosuppressed hosts:
invasive pulmonary infection, usually
with fever, cough, and chest pain.
May disseminate to other organs,
including brain, skin and bone. In
immunocompetent hosts: localized
pulmonary infection in persons with
underlying lung disease. Also causes
allergic sinusitis and allergic
bronchopulmonary disease.
Agent: Aspergillus fumigatus, A. flavus.

33. Environmental species kill neutropenic
patients.
• Zygomycosis. Zygomycosis due to Rhizopus, Rhizomucor, Absidia, Mucor species,
or other members of the class of Zygomycetes, also causes invasive
sinopulmonary infections. An especially life-threatening form of zygomycosis
(also known as mucormycosis), is known as the rhinocerebral syndrome, which
occurs in diabetics with ketoacidosis. In addition to diabetic ketoacidosis,
neutropenia and corticosteroids are other major risk factors for zygomycosis.
• Phaeohyphomycosis. Phaeohyphomycosis is an infection by brown to black
pigmented fungi of the cutaneous, superficial, and deep tissues, especially brain.
These infections are uncommon, life-threatening, and occur in various
immunocompromised states.
• Hyalohyphomycosis. Hyalohyphomycosis is an opportunistic fungal infection
caused by any of a variety of normally saprophytic fungi with hyaline hyphal
elements. For example, Fusarium spp. infect neutropenic patients to cause
pneumonia, fungemia, and disseminated infection with cutaneous lesions.

34. …. 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

35. ….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

36. Find out. personal assignment. indicate
sources, pathogenesis and tests

37. . Aflatoxins are known contaminants on
corn, peanuts, tree nuts, cottonseed
and certain meats and hypoallergenic
milks

38. Diagnosis/Treatment
1. Grown in medium that selects
for fungal growth
-Grow at 25 C and 37 C
2. KOH preparations of skin
biopsies
-Dissolves keratin in skin scrapings or
biopsies
-Leaves only fungal cells6/21/2017 WALTER WASWA 38

39. The end
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