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Opportunistic Mycoses

Opportunistic Mycoses. Ordinary fungi causing extraordinary disease. Opportunistic Mycoses. Infections due to fungi of low virulence in patients who are immunologically compromised. Medical Mycology Iceberg. PATHOGENIC FUNGI. NORMAL HOST Systemic pathogens - 25 species

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Opportunistic Mycoses

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  1. Opportunistic Mycoses Ordinary fungi causing extraordinary disease

  2. Opportunistic Mycoses Infections due to fungi of low virulence in patients who are immunologically compromised

  3. Medical Mycology Iceberg

  4. PATHOGENIC FUNGI • NORMAL HOST • Systemic pathogens - 25 species • Cutaneous pathogens - 33 species • Subcutaneous pathogens - 10 species • IMMUNOCOMPROMISED HOST Opportunistic fungi - 300 species

  5. HOST-PATHOGEN EQUILIBRIUM NUMBER OF ORGANISMS X VIRULENCE = DISEASE HOST RESISTANCE

  6. Opportunistic Fungi 1. Saprophytic - from the environment 2. Endogenous – a commensal organism

  7. Opportunistic Fungi Include many species from: A (Aspergillus) To Z (Zygomyces)

  8. MOST SERIOUS OPPORTUNISTIC INFECTIONS • CANDIDA SPECIES • ASPERGILLUS SPECIES • MUCOR SPECIES (ZYGOMYCES)

  9. Upward Trend InOpportunistic Mycoses • Increased clinical awareness • Improved clinical diagnostic tools • Improved laboratory diagnostic technics • An increase in susceptible hosts. • More invasive diagnostic and therapeutic procedures

  10. Must distinguish between • Transient fungemia • Colonization • Infection

  11. Transient fungemia The fortuitous isolation of a commensal or environmental organism

  12. COLONIZATION MOUTH RESPIRATORYTRACT EYE Multiplication of an organism at a given site without harm to the host SKIN UROGENITAL TRACT ANUS

  13. INFECTION MOUTH RESPIRATORYTRACT EYE Invasion and multiplicationof organisms in body tissue resulting inlocal cellular injury. SKIN UROGENITAL TRACT ANUS

  14. Predisposing Factors Malignancies • Leukemias • Lymphomas • Hodgkins Disease

  15. Predisposing Factors Drug therapies • Anti-neoplastics • Steroids • Immunosuppressive drugs

  16. Predisposing Factors Antibiotics Over-use or inappropriate use of antibiotics alter the normal flora allowing fungal overgrowth

  17. Predisposing Factors Therapeutic procedures • Solid organ or bone marrow transplant • Open heart surgery • Indwelling catheters • Artificial heart valves • Radiation therapy

  18. Predisposing Factors Other Factors • Severe burns • Diabetes • Tuberculosis • IV Drug use

  19. Predisposing Factors AIDS

  20. Human Immunodeficiency Virus(HIV) HIV destroys the CD4 helper T cells

  21. CD4 helper T cells are the basis of cell mediated immunity and play a role in host defenses against fungal diseases ERGO

  22. Virtually all AIDS patients will have a fungal infection sometime during the course of their illness

  23. BIOFILMS A POLYSACCHARIDE SLIME WHICH IS A MICROCOLONY OF ORGANISMS CONTAINING CHANNELS TO BRING IN NUTRIENTS AND CARRY OFF WASTE

  24. 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

  25. CLINICAL PRESENTATION Atypical Signs and Symptoms Unusual Organ Affinity Outside Endemic Area Unusual histopathology Unusual Pathogens Depressed serological response

  26. NORMAL PATIENT Malasezzia furfur Tinea versicolor (mild disease)

  27. COMPROMISED PATIENTS Malasezzia furfur can cause disseminated infection--------Particularly in patients receiving hyperalimentation.

  28. COMPROMISED IMMUNESYSTEMMalasezzia furfur NUMBER OF ORGANISMS x LOW VIRULENCE= DISEASE HOST RESISTANCE

  29. CLINICAL PRESENTATION Atypical Signs and Symptoms Unusual Organ Affinity Outside Endemic Area Unusual histopathology Unusual Pathogens Depressed serological response

  30. Candida species Endogenous

  31. Normal Flora The population of microorganisms that may be found residing in or on the human body without causing disease.

  32. COMPETENT IMMUNESYSTEMCandida albicans NUMBER OF ORGANISMS x VIRULENCE= NO DISEASE HOST RESISTANCE

  33. COMPROMISED IMMUNESYSTEMCandida albicans NUMBER OF ORGANISMS = DISEASE HOST RESISTANCE

  34. IMMUNOCOMPROMISED PATIENTS CAN DEVELOP HEPATIC CANDIDIASIS

  35. Candida species In the previous lecture I only mentioned Candida albicans. There are several Candida species that infect the compromised host.

  36. Candida species • C. glabrata • C. krusei • C. torulopsis • C. parapsilosis • C. lusitaniae • C. dubliniensis

  37. Cryptococcosis A sub-acute or chronic infection which may affect the lungs or skin but most commonly manifests as a meningitis

  38. Ecological Niche Cryptococcus neoformans • pigeon droppings • Chicken droppings

  39. Cryptococcus neoformansPORTAL OF ENTRY INHALATION INOCULATION

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