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Opportunistic mycosis Dr.Huda Ibrahim

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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)

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

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

6 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,

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.

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

9 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

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

11 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.

12 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.

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

14 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

15 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

16 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. 16

17 Diagnosis of opportunistic infections requires a high index of suspicion
Atypical signs or symptom...M.furfur Unusual organ affinity…liver candidiasis Outside the endemic area Unusual Histopathology…necrosis Etiologic agent may be a “saprophyte” Serological response may be suppressed

18 IMPROVING TREATMENT New Drugs…Echinocandin New therapeutic regimen
Aggressive therapy…prophylactic Conjunctive therapy..Immunotherapy IL, IFN,CSF

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


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