Presentation on theme: "Opportunistic mycosis Dr.Huda Ibrahim"— Presentation transcript:
1 Opportunistic mycosis Dr.Huda Ibrahim Mycology Lec,7Opportunistic mycosisDr.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 fungi1. 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 AntibioticsBurns and other skin problemsCatheter- related problemsDevices (prosthetic)Effects on mucosal integrityFungus isolated previously
5 Inducing Immunosuppression AIDSBone marrow/ organ transplantationCancer: Leukemia, lymphoma etcDrugs: Cytotoxic drugs,steroids etcEndocrine related: DiabetesFailure of organs: multi-organ
6 Candida albicans and other Candida species Harmless inhabitants of the skin and mucous membranes of all humansNormal immune system keeps candida on body surfacesAs 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,
7 THE MOST IMPORTANT RISK FACTORS 1. Neutropenia(less than 100 N/L)2. Diabetes mellitus3. AIDS5. Myeloperoxidase defects6. Broad-spectrum antibioticsIn diabetic patients, fusion of lysosome in phagocytes is greatly impaired.
8 THE MOST IMPORTANT RISK FACTORS 7. Indwelling catethers8. Major surgery9. Organ transplantation10. Neonates11. Severity of any illness12. Intravenous drug addicts
9 INVASIVE CANDIDIASISIf 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
10 DIAGNOSIS OF INVASIVE CANDIDIASIS Gram stain and isolation from blood, CSF , urine ,sputum or peritoneal fluidSerologyPCR (promising)isolation and/or pathology positive of organ involved
11 EPIDEMIOLOGYAlthough candidiasis is endogenous in most cases, cross infections are described, especially in intensive care unit patients.Account for 80% of nosocomial fungal infectionsAccount for 30% of deaths from nosocomial infectionsHandwashing 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 roostsCommon infection of AIDS, cancer or diabetes patientsInfection of lungs leads to cough, fever, and lung nodulesDissemination to meninges and brain can cause severe neurological disturbance and death.
13 Diagnosis Serology Microscopic Culture India Ink for capsule stain (50-80% + CSF)GramSilver stainCultureBird seed agarRoutine blood cultureSerology
14 Aspergillosis: Diseases of the Genus Aspergillus Very common airborne soil fungus600 species, 8 involved in human disease; A. fumigatus most commonlySerious opportunistic threat to AIDS, leukemia, and transplant patientsInfection usually occurs in lungs – spores germinate in lungs and form fungal balls; can colonize sinuses, ear canals, eyelids, and conjunctivaInvasive aspergillosis can produce necrotic pneumonia, and infection of brain, heart, and other organs.Amphotericin B and nystatin
15 ZygomycosisZygomycota 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 &hotericin BPrognosis: very poorPulmonary 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.furfurUnusual organ affinity…liver candidiasisOutside the endemic areaUnusual Histopathology…necrosisEtiologic agent may be a “saprophyte”Serological response may be suppressed
18 IMPROVING TREATMENT New Drugs…Echinocandin New therapeutic regimen Aggressive therapy…prophylacticConjunctive therapy..ImmunotherapyIL, IFN,CSF
19 “Only the prepared mind can help the impaired host” Libero Ajello, Chief Mycology Division, CDC 1972