1. Opportunistic mycosis Dr.Huda Ibrahim
Mycology Lec,7
Opportunistic mycosis
Dr.Huda Ibrahim

2. Oppurtunistic mycosis
Ordinary fungi causing extraordinary disease Infections due to fungi of low virulence in patients who are immunologically compromised

3. Opportunistic fungi
1. Saprophytic - from the environment e.g.,Cryptococcus sp. , Aspergillus, Zycomycetes.
2. Endogenous – a commensal organism e.g., Candida sp.
Include many species from: A (Aspergillus)
To Z (Zygomyces)

5. Predisposing Factors: Providing a Route/ Source
Antibiotics
Burns and other skin problems
Catheter- related problems
Devices (prosthetic)
Effects on mucosal integrity
Fungus isolated previously

6. Inducing Immunosuppression
AIDS
Bone marrow/ organ transplantation
Cancer: Leukemia, lymphoma etc
Drugs: Cytotoxic drugs,steroids etc
Endocrine related: Diabetes
Failure of organs: multi-organ

7. Candida albicans and other Candida species
Harmless inhabitants of the skin and mucous membranes of all humans
Normal immune system keeps candida on body surfaces
As Candida is present in practically all humans, it has many opportunities to cause endogenous infections in compromised host - so, Candida infections are the most frequent opportunistic fungal infections.
Other Candida species are: C.tropicalis, C.krusei, C.parapsilosis, C.glabrata,

8. THE MOST IMPORTANT RISK FACTORS
1. Neutropenia(less than 100 N/L)
2. Diabetes mellitus
3. AIDS
5. Myeloperoxidase defects
6. Broad-spectrum antibiotics
In diabetic patients, fusion of lysosome in phagocytes is greatly impaired.

9. THE MOST IMPORTANT RISK FACTORS
7. Indwelling catethers
8. Major surgery
9. Organ transplantation
10. Neonates
11. Severity of any illness
12. Intravenous drug addicts

10. INVASIVE CANDIDIASIS
If phagocytic system is compromised, infection spreads to many organs and causes focal infection in these organs (kidney ,eye ,heart , liver , meninges)
mortality of candidemia is 30-40%
Prophylactic antifungal drugs during cytotoxic course of therapy

11. DIAGNOSIS OF INVASIVE CANDIDIASIS
Gram stain and isolation from blood, CSF , urine ,sputum or peritoneal fluid
Serology
PCR (promising)
isolation and/or pathology positive of organ involved

12. EPIDEMIOLOGY
Although candidiasis is endogenous in most cases, cross infections are described, especially in intensive care unit patients.
Account for 80% of nosocomial fungal infections
Account for 30% of deaths from nosocomial infections
Handwashing is the most important activity to prevent spread of many hospital pathogens, and of Candida too.

13. Cryptococcosis and Cryptococcus neoformans
Cryptococcus neoformans causes cryptococcosis.
A widespread encapsulated yeast that inhabits soil around pigeon roosts
Common infection of AIDS, cancer or diabetes patients
Infection of lungs leads to cough, fever, and lung nodules
Dissemination to meninges and brain can cause severe neurological disturbance and death.

14. Pulmonary Cryptococcus

15. Diagnosis Microscopic Culture
India Ink for capsule stain (50-80% + CSF)
Gram
Calcoflur white
Silver stain
Culture
Bird seed agar
Routine blood culture

16. Diagnosis Serology Radiology
Latex agglutination, EIA, 90% sensitive & specific
Radiology
CXR – infiltrates, nodules, lymphadenopathy, cavitation, effusion
CT/MRI – 50% normal, hydrocephalus

17. Therapy – Cryptococcal meningitis
Amphotericin B +/- flucytosine
Fluconazole
Amphotercin x 2 wk then fluconazole mg/d x 8-10 wk
Chronic suppression fluconazole 200 mg/d

18. Aspergillosis: Diseases of the Genus Aspergillus
Very common airborne soil fungus
600 species, 8 involved in human disease; A. fumigatus most commonly
Serious opportunistic threat to AIDS, leukemia, and transplant patients
Infection usually occurs in lungs – spores germinate in lungs and form fungal balls; can colonize sinuses, ear canals, eyelids, and conjunctiva
Invasive aspergillosis can produce necrotic pneumonia, and infection of brain, heart, and other organs.
Amphotericin B and nystatin

19. Zygomycosis
Zygomycota are extremely abundant saprophytic fungi found in soil, water, organic debris, and food.
Genera most often involved are Rhizopus, Absidia, and Mucor.
Usually harmless air contaminants invade the membranes of the nose, eyes, heart, and brain of people (Rhinocerebral mucormycosis) with diabetes and malnutrition, with severe consequences.
main host defense is phagocytosis

20. Control Diabetes ,surgery & amphotericin B Prognosis: very poor
Diagnosis is made by direct smear and by isolation of molds from respiratory secretions or biopsy specimens.
Treatment:
Control Diabetes ,surgery &
amphotericin B
Prognosis: very poor
Pulmonary infection can also occur, with very high mortality rate.
Diagnosis is made by direct smear and by isolation of molds from respiratory secretions or biopsy specimens. 20

21. Diagnosis of opportunistic infections requires a high index of suspicion
Atypical signs or symptoms
Unusual organ affinity
Outside the endemic area
Unusual Histopathology
Etiologic agent may be a “saprophyte”
Serological response may be suppressed

22. A typical sign & symptoms
Malasezzia furfur
Tinea versicolor
(mild disease in normal person)
can cause disseminated infection Particularly in patients receiving hyperalimentation (compromsed pt..

24. Unusual organ affinity
Immunocompromised patients can develop hepatic candidiasis
Liver infected with Candida albicans

26. Outside Endemic Area Disseminated coccidioidomycosis, Histoplasmosis
(not pulmonary)

27. Unusual Histopathology
NORMAL HOST
PYOGENIC
GRANULOMATOUS
IMMUNODEFICIENT HOST
NECROTIC

28. Unusual pathogen Penicillium marneffei Usually not a pathogen
The only dimorphic penicillium
Produces a red pigment
Endemic in the Far East

31. IMPROVING TREATMENT New Drugs New therapeutic regimen
Aggressive therapy
Conjunctive therapy

32. IMPROVING TREATMENT New Drugs Lipid Amphotericin B
Third generation azoles
(Posaconazole, Voriconazole)
New classes of antifungal agents
(Echinocandins)

33. New Therapeutic Regimen
IMPROVING TREATMENT
New Therapeutic Regimen
Combination Therapy
Simultaneously administering two drugs
Sequential Tx with two or more drugs
Alternate Administration of two or more

34. FOR IMMUNOCOMPROMISED PATIENTS
IMPROVING TREATMENT
AGGRESSIVE THERAPY
FOR IMMUNOCOMPROMISED PATIENTS
Prophylactic – Anti-fungal agents at, or near, the time of chemotherapy
Fluconazole , Posaconazole now approved.

35. IMPROVING TREATMENT CONJUNJUNCTIVE THERAPY
FOR IMMUNOCOMPROMISED PATIENTS
The use of anti-fungal agents with immunotherapy:
*Interferons
Colony stimulating factors
Interleukins

36. OPPORTUNISTIC FUNGAL INFECTIONS ARE:
difficult to diagnose
difficult to treat
difficult to prevent
more and more frequent
a great challenge for a future work in all fields 36

37. “Only the prepared mind can help the impaired host”
Libero Ajello, Chief Mycology Division, CDC 1972

38. MYCOLGISTS have more
FUNGI