This document describes several opportunistic mycoses (fungal infections) that primarily affect immunocompromised individuals. It discusses the most common fungal pathogens, including Candida, Aspergillus, Cryptococcus, Pneumocystis, Rhizopus, Mucor, and Absidia. For each pathogen, it covers topics like etiology, clinical manifestations, diagnosis, and treatment. The goal is to describe the etiology, morphology, pathogenesis and clinical spectrum of opportunistic mycoses, as well as elaborate on their laboratory diagnosis and treatment.

1. 1
Mohamed Abdullatif Abdurahman
B.Pharm, MMM

2. Objectives
• To describe the etiology, morphology,
pathogenesis, clinical spectrum of
opportunistic mycoses
• To elaborate the laboratory diagnosis and
treatment of Opportunistic mycoses.
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3. 3
Opportunistic Mycoses
• Most important fungal pathogens:
Candida
Aspergillus
Cryptococcus
Pneumocystis
Rhizopus
Mucor
Absidia

4. 4
Candidiasis
• Candida albicans, C.parapsilosis,
C.glabrata, C.tropicalis,
C.guilliermondii, and C.dubliniensis.
• Widespread yeast
• They are members of the normal flora
of the skin, mucous membranes, and
gastrointestinal tract.

5. • Budding cells of varying size that
may form both elongate
pseudohyphae and true hyphae
• Forms off-white, pasty colony with a
yeasty odor
• Infections can be short-lived,
superficial skin irritations to
overwhelming, fatal systemic
diseases 5

6. 6
Candida albicans
• Normal flora of oral
cavity, genitalia, large
intestine or skin of
humans
• Account for 80% of
nosocomial fungal
infections
• Account for 30% of
deaths from nosocomial
infections

7. • Thrush:occurs as a thick,
white, adherent growth on the
mucous membranes of mouth
and throat
• Vulvovaginal yeast infection:
painful inflammatory condition
of the female genital region
that causes ulceration and
whitish discharge
• Cutaneous candidiasis:occurs
in chronically moist areas of
skin and in burn patients
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8. • Systemic Candidiasis
• Candidemia can be caused by
indwelling catheters, surgery,
intravenous drug abuse, aspiration, or
damage to the skin or gastrointestinal
tract.
• Occult lesions anywhere, especially
the kidney, skin (maculonodular
lesions), eye, heart, and meninges.
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9. 9
Diagnosis and Treatment
• Presumptive diagnosis made if budding yeast
cells and pseudohyphae are found; germ tube
• Growth on selective, differential media
differentiates Candida species
• Topical antifungals such as Nystatin for
superficial infections, amphotericin B and
fluconazole for systemics
• The most important preventive measure is to
avoid disturbing the normal balance of
microbiota and intact host defenses.

10. 10
Cryptococcosis
• Caused by Cryptococcus
neoformans and Cryptococcus
gattii.
• A widespread encapsulated
yeast that inhabits soil around
pigeon roosts
• Common infection of AIDS,
cancer or diabetes patients

11. • Infection of lungs leads
to cough, fever, and lung
nodules
• Dissemination to
meninges and brain can
cause severe
neurological disturbance
and death.
• They infect many other
organs (eg, skin, eyes,
prostate).
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12. Diagnosis
• Microscopic examination of CSF mounted in
Indian ink reveals encapsulated yeast cells.
• Culture at 37°C produce whitish mucoid
colonies within 2–3 days.
• Detection of Ag and Ab is also effective.
Treatment:
• Systemic infection requires amphotericin B and
fluconazole.
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13. 13
Aspergillosis
• Very common airborne soil fungus
• 600 species, 8 involved in human
disease; A. fumigatus most
commonly
• Others A flavus, A niger, A terreus,
and A lentulus
• The species are identified according
to differences in the size, shape,
texture, and color of the conidia.

14. Clinical Findings
A. Allergic Forms
• Uncommon Bronchial allergic reaction seen in
atopic individuals mainly due to IgE antibodies
to the surface antigens of Aspergillus conidia
which elicits an immediate asthmatic reaction
upon subsequent exposure.
• Allergic bronchopulmonary aspergillosis
occur when the conidia germinate and hyphae
colonize the bronchial tree without invading the
lung parenchyma
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15. B.Aspergilloma (fungus ball)
• Occurs when inhaled conidia enter an existing
cavity. (eg, tuberculosis, sarcoidosis, emphysema)
• Often asymptomatic but Chronic cough, dyspnea,
malaise, weight loss and haemoptysis may occur.
• Localized, noninvasive infections may involve the
nasal sinuses, the ear canal, the cornea, or the nails.
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16. C. Invasive Aspergillosis
• From the lungs, the disease may spread
to the gastrointestinal tract, kidney, liver,
brain, or other organs, producing
abscesses and necrotic lesions.
• Hyphae invade the lumens and walls of
blood vessels, causing thrombosis,
infarction, and necrosis.
• Symptoms include fever, cough,
dyspnea, and hemoptysis.
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17. 17
• Diagnosis:
• Sputum samples show
hyaline and septate
hyphae under microscope
• The ID test for precipitins
to A fumigatus is positive
in over 80% of patients
with aspergilloma or
allergic forms

18. Treatment:
• Allergic aspergillosis does not require
treatment, but when treatment is
indicated, prednisolone is drug of choice.
• Aspergilloma is treated with Itraconazole
or Amphotericin B and surgery.
• Invasive aspergillosis requires rapid
administration of amphotericin B or
voriconazole,
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19. 19
Zygomycosis
• Zygomycota are extremely
abundant saprobic fungi found in
soil, water, organic debris, and
food.
• Genera most often involved are
Rhizopus, Absidia, Mucor,
Lichtheimia & Cunninghamella
• Produce abundant cottony
colonies
• Diagnosis based on the
sporangial structures

20. • Usually harmless air contaminants invade the
membranes of the nose, eyes, heart, and brain of
people with diabetes and malnutrition,
leukemias, lymphoma, corticosteroid treatment,
severe burns and immunodeficiencient.
• Clinical form is rhinocerebral mucormycosis,
and Thoracic mucormycosis
• Surgical debridement and amphotericin B,
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21. 21
Pneumocystis Pneumonia
• Caused by
Pneumocystis jiroveci
and Pneumocystis
carinii.
• A small, unicellular
fungus that causes
pneumonia (PCP), the
most prominent
opportunistic infection
in AIDS patients

22. • This pneumonia forms secretions in the lungs
that block breathing and can be rapidly fatal if
not controlled with medication.
• Pentamidine and cotrimoxazole
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23. Concept check
• Immunocompromised persons are suffered from
several fungal diseases. Which of the following is
the least frequently associated
a. Cryptococcus neoformans
b. Aspergillus fumigatus
c. Malassezia furfur
d. Mucor species 23

24. Thank you
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