1 / 38

SYSTEMIC MYCOSIS

SYSTEMIC MYCOSIS. III MBBS. Systemic Mycosis. Fungal infection of internal organs. Primarily involve the respiratory system. Infection occurs by inhalation of air- borne conidia. More than 95% are self limiting & asymptomatic. Rest are symptomatic & disseminate by hematogenous route.

mabyn
Download Presentation

SYSTEMIC MYCOSIS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SYSTEMIC MYCOSIS III MBBS Dr Ekta, Microbiology, GMCA

  2. Systemic Mycosis • Fungal infection of internal organs. • Primarily involve the respiratory system. • Infection occurs by inhalation of air- borne conidia. • More than 95% are self limiting & asymptomatic. • Rest are symptomatic & disseminate by hematogenous route. Dr Ekta, Microbiology, GMCA

  3. Systemic Mycosis • Caused by dimorphic fungi which infect healthy & immunocompetent individuals. • Other systemic infections found in immunocompromised patients are called as opportunistic mycotic infections. • Includes : Histoplasma capsulatum Blastomyces dermatitidis Coccidioides immitis Paracoccidioides brasiliensis Dr Ekta, Microbiology, GMCA

  4. HISTOPLASMOSIS • Intracellular infection of the RES caused by Histoplasma capsulatum. Endemic in parts of USA • Also called Darling’s disease; 1st described by Samuel Darling. “histio” within histiocytes “plasma” resembled plasmodium. • Present in soil, rotting areas and in feces of chicken, bats & other birds. (high N2 content) Dr Ekta, Microbiology, GMCA

  5. Pathogenesis & Pathology Inhalation of conidia or mycelial fragments Converted into yeast in alveolar macrophages Localized granulomatous inflammation Granuloma with or assist in without caseation dissemination to RES • Involves all phagocytic cells of RES, cytoplasm being studded with fungal cells. Dr Ekta, Microbiology, GMCA

  6. Clinical features • Resembles TB – mainly asymptomatic • Clinical types – • Pulmonary • Cutaneous & mucocutaneous • Disseminated histoplasmosis – commonly seen in children below 2 yrs & adolescents - individuals with HIV are at a greater risk. Dr Ekta, Microbiology, GMCA

  7. Laboratory Diagnosis Specimen – sputum, BM, LNs, scrapings from lesions, biopsy & peripheral blood. Direct Examination • Blood smear – Giemsa or Wright stains. - small, oval yeast like cells, 2-4µ within mononuclear or polymorphonuclear cells, narrow neck budding. • Fluorescent Ab technique. Dr Ekta, Microbiology, GMCA

  8. Fungal Culture • SDA , BHI at 25° & 37°C. • LPCB - White cottony mycelia with large (8-20µ) thick walled, spherical spores with tubercles or finger like projections – Tuberculate Macroconidia. Dr Ekta, Microbiology, GMCA

  9. Immunodiagnosis • Histoplasmin skin test – I.D. test with 0.1 ml histoplasmin Ag – DTH response. • Serological tests – LPA * titer of 1:32 or higher or 4-fold increase in titer of Abs is significant. Dr Ekta, Microbiology, GMCA

  10. Treatment & Prophylaxis • Amphotericin B – disseminated & other severe forms. • Oral Itraconazole • Regular cleaning of farm buildings, chicken houses for prevention. Dr Ekta, Microbiology, GMCA

  11. BLASTOMYCOSIS • Also called as Gilchrist’s disease or Chicagodisease due to its endemicity in N.America (N.American blastomycosis) • Caused by Inhalation of the spores of Blastomyces dermatitidis • Causes suppurative & granulomatous infection Dr Ekta, Microbiology, GMCA

  12. Clinical features • 1° infection resembles TB or histoplasmosis. • Clinical types: • Pulmonary • Cutaneous – commonest form, hence the name “dermatitidis”. - seen over exposed parts like face, neck & hands. • Disseminated type – form multiple abscesses in different parts like bone, genitourinary system, breast etc Dr Ekta, Microbiology, GMCA

  13. Laboratory Diagnosis Specimen – sputum, BAL, biopsy or pus from abscesses, urine. Direct Examination • Wet mount – KOH, CFW : double contoured, thick walled, multinucleate giant yeast cells with broad base budding daughter cells. Dr Ekta, Microbiology, GMCA

  14. Fungal Culture • Very slow growth – 2 to 4 weeks. • Tissue & cultures at 37°C shows budding yeast cells. • At 25°C - fine, branched septate hypha with conidia measuring 2-10µ located on short terminal or lateral branches. Dr Ekta, Microbiology, GMCA

  15. Diagnosis • Immunodiffusion precipitation bands. • EIA / RIA • Skin test using blastomycin Treatment & Prophylaxis • Initial phase - Oral Ketoconazole & Itraconazole • Life threatening infections - AMB Dr Ekta, Microbiology, GMCA

  16. COCCIDIOIDOMYCOSIS • Infection of the respiratory system caused by Coccidioides immitis. • Most virulent of all the fungal pathogens but not contagious. • More prevalent in western hemisphere. • Fungus present in soil & in rodents. • Infection occurs by - inhalation of arthroconidia or - reactivation of latent infection in immunocompromised patients. Dr Ekta, Microbiology, GMCA

  17. Clinical features • Many develop influenza like fever – Valley fever or Desert Rheumatism • < 1% develop chronic progression disseminated disease – - skin (commonest) : granuloma, cold abscess. - osteomyelitis & synovitis - CNS (meningitis) Dr Ekta, Microbiology, GMCA

  18. Laboratory Diagnosis Specimen – sputum, gastric contents, CSF, exudate or pus. Direct Examination • Presence of doubly refractile thick walled globular spherules (30-60µ in dia) filled with endospores • Tissue – HE, PAS & GMS Dr Ekta, Microbiology, GMCA

  19. Fungal Culture • Different from other dimorphic fungi – grows as mold at 25° & 37°C under standard conditions. • Growth in 3 - 5 days at 25°C • LPCB of culture shows branching septate hypha & chains of thick walled rectangular arthroconidia. • Arthroconidia are mature infectious propagules that develop from alternate cells on hypha. Dr Ekta, Microbiology, GMCA

  20. Immunodiagnosis • Skin tests – I.D. inoculation of coccidioidin: positive is >5mm in 24-48 hours. • Serology – detection of Abs Treatment & Prophylaxis • Rapidly progressive disease – AMB • Chronic, mild to moderate - azoles Dr Ekta, Microbiology, GMCA

  21. PARACOCCIDIOIDOMYCOSIS • Acute or chronic, granulomatous infection • primarily of lungs & • disseminates to skin, mucosa, LNs & other internal organs. • Caused by Paracoccidioides brasiliensis. • Confined to S.America (S.American blastomycosis). Dr Ekta, Microbiology, GMCA

  22. Laboratory Diagnosis Specimen – sputum, BAL, pus & crusts from granulomatous lesions, biopsy Direct Examination Wet mount - KOH, CFW - round refractile yeast cells 2-10 to 30µ - single or chain of cells Tissuestains – HE, GMS Dr Ekta, Microbiology, GMCA

  23. Fungal Culture • SDA, BHIA & BA incubated at 25° & 37°C. • At 25°C – colonies are white to tan in colour,with a yellowish-brown reverse LPCB - mycelia bearing conidia & numerous intercalary chlamydospores. • 37°C – off-white to cream, rough to pasty. LPCB- spherical mother cell surrounded by multiple thin-necked daughter cells: “Mariner’s wheel” Dr Ekta, Microbiology, GMCA

  24. Treatment & Prophylaxis • Long term therapy • Reviewed periodically as relapses are frequent • AMB combined with sulfonamides • Oral Itraconazole Dr Ekta, Microbiology, GMCA

  25. CANDIDIASIS • Commonest fungal disease in humans • Affects mucosa, skin, nails & internal organs - superficial and deep infections • Caused by yeast- like fungi of genus candida. • Candida albicans : commonest pathogenic species. • Normal flora of skin, GIT & female genital tract. • Commonest fungal infection in HIV+ve individuals Dr Ekta, Microbiology, GMCA

  26. Epidemiology • Predisposing factors • Natural receptive states like infancy, old age, pregnancy. • Changes in local bacterial flora 2º to antibiotics. • Endocrine diseases like DM • Severe chronic underlying debilitated conditions • Malignancy • Drugs – steroids, immunosuppressants & chemotherapeutic agents. • Trauma, burns or injury. Dr Ekta, Microbiology, GMCA

  27. Pathogenesis & Pathology • Adhesion – entry into host as yeast cell • Local colonization & invasion into deeper tissues • Hyphal form - phospholipase at tip - invasion large size - resistant to phagocytosis • Biofilm formation around cells – facilitates survival of organisms. Dr Ekta, Microbiology, GMCA

  28. Clinical Classification of Candidiasis Dr Ekta, Microbiology, GMCA

  29. Mucocutaneous Manifestations • Oral candidiasis or oral thrush – commonest form: - Creamy white patches on tongue or buccal mucosa - 90% of AIDS pt. • Vaginitis - Young & middle – aged females, during active reproductive life. - Acidic discharge, itching & burning sensation Dr Ekta, Microbiology, GMCA

  30. Cutaneous Manifestations • Intertriginous – skin folds • Paronychia – nail folds • Diaper dermatitis – in babies - maceration & wet diapers Systemic Candidiasis • Gastrointestinal candidiasis - follow oral antibiotic therapy - in leukemia & hematological malignancy: ulcerations, peritonitis Dr Ekta, Microbiology, GMCA

  31. Clinical forms of Candidiasis in HIV patients • Asymptomatic oral carriage • Oropharyngeal thrush • Angular cheilitis • Leukoplakia • Oesophagitis • Laryngitis • Vulvovaginitis, balanitis • Acute atrophic erythema • Hematogenous dissemination Dr Ekta, Microbiology, GMCA

  32. Laboratory Diagnosis • Clinical specimens are collected depending on the site of involvement. Direct Examination • Wet mount – KOH - Yeast cells, 4-8 with budding & pseudohyphae • Gram’s stain – gram +ve budding yeast cells Dr Ekta, Microbiology, GMCA

  33. Fungal Culture • SDA & other bacteriological media • Colonies appear in 2-3 days. • Creamy white, smooth & pasty. Identification ofspecies using • Tetrazolium reduction medium (TRM) • CHROM agar Dr Ekta, Microbiology, GMCA

  34. C.tropicalis C.krusei C.albicans CHROM Agar Dr Ekta, Microbiology, GMCA

  35. Germ tube test • Culture is treated with sheep or normal human serum. • Incubated at 370Cfor 2 to 4 hrs. • Wet mount : shows long tube – like projections extending from the yeast cells, called GERM TUBE. • Positive for - C. albicans - C. dubliniensis - C. tropicalis (sometimes) • Also known as Reynolds – braude phenomenon. Dr Ekta, Microbiology, GMCA

  36. CANDIDA – GERM TUBE Dr Ekta, Microbiology, GMCA

  37. Chlamydospore formation • Cornmeal agar or Rice starch agar • Incubated at 250c • Large, highly refractive, thick – walled chlamydospores after 2-3 days of incubation. Biochemical tests • Sugar fermentation • Sugar assimilation Dr Ekta, Microbiology, GMCA

  38. Treatment & Prophylaxis • Correct the underlying condition • Oral & Mucocutaneous – 1% Gentian violet • Resistant mucosal lesions – Nystatin • Vaginal candidiasis – oral fluconazole (single dose), suppositories & creams • Systemic lesions – AMB • Oral antifungals Dr Ekta, Microbiology, GMCA

More Related