Systemic Mycosis

38
SYSTEMIC MYCOSIS III MBBS

description

mycoses

Transcript of Systemic Mycosis

  • SYSTEMIC MYCOSIS III MBBS

    Dr Ekta, Microbiology, GMCA

  • Systemic MycosisFungal 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.

  • Systemic MycosisCaused 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

  • 17/12/07Dr Ekta, Microbiology, GMCAHISTOPLASMOSISIntracellular infection of the RES caused by Histoplasma capsulatum. Endemic in parts of USA

    Also called Darlings 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

  • 17/12/07Dr Ekta, Microbiology, GMCAPathogenesis & PathologyInhalation 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

  • 17/12/07Dr Ekta, Microbiology, GMCAClinical featuresResembles TB mainly asymptomaticClinical types PulmonaryCutaneous & mucocutaneousDisseminated histoplasmosis commonly seen in children below 2 yrs & adolescents - individuals with HIV are at a greater risk.

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCALaboratory Diagnosis Specimen sputum, BM, LNs, scrapings from lesions, biopsy & peripheral blood.

    Direct Examination Blood smear Giemsa or Wright stains. - small, oval yeast like cells, 2-4 within mononuclear or polymorphonuclear cells, narrow neck budding.Fluorescent Ab technique.

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAFungal CultureSDA , BHI at 25 & 37C.

    LPCB - White cottony mycelia with large (8-20) thick walled, spherical spores with tubercles or finger like projections Tuberculate Macroconidia.

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAImmunodiagnosis 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

  • 17/12/07Dr Ekta, Microbiology, GMCATreatment & ProphylaxisAmphotericin B disseminated & other severe forms.

    Oral Itraconazole

    Regular cleaning of farm buildings, chicken houses for prevention.

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCABLASTOMYCOSISAlso called as Gilchrists disease or Chicago disease 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

  • 17/12/07Dr Ekta, Microbiology, GMCAClinical features1 infection resembles TB or histoplasmosis.Clinical types:PulmonaryCutaneous 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

  • 17/12/07Dr Ekta, Microbiology, GMCALaboratory Diagnosis Specimen sputum, BAL, biopsy or pus from abscesses, urine.

    Direct ExaminationWet mount KOH, CFW : double contoured, thick walled, multinucleate giant yeast cells with broad base budding daughter cells.

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAFungal CultureVery slow growth 2 to 4 weeks.Tissue & cultures at 37C shows budding yeast cells.At 25C - fine, branched septate hypha with conidia measuring 2-10 located on short terminal or lateral branches.

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCADiagnosis Immunodiffusion precipitation bands.EIA / RIASkin test using blastomycin

    Treatment & ProphylaxisInitial phase - Oral Ketoconazole & Itraconazole Life threatening infections - AMB

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCACOCCIDIOIDOMYCOSISInfection 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

  • 17/12/07Dr Ekta, Microbiology, GMCAClinical featuresMany 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

  • 17/12/07Dr Ekta, Microbiology, GMCALaboratory Diagnosis Specimen sputum, gastric contents, CSF, exudate or pus.

    Direct ExaminationPresence of doubly refractile thick walled globular spherules (30-60 in dia) filled with endosporesTissue HE, PAS & GMS

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAFungal CultureDifferent from other dimorphic fungi grows as mold at 25 & 37C under standard conditions.

    Growth in 3 - 5 days at 25C

    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

  • 17/12/07Dr Ekta, Microbiology, GMCAImmunodiagnosis Skin tests I.D. inoculation of coccidioidin: positive is >5mm in 24-48 hours.Serology detection of Abs

    Treatment & ProphylaxisRapidly progressive disease AMBChronic, mild to moderate - azoles

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAPARACOCCIDIOIDOMYCOSISAcute 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

  • 17/12/07Dr Ekta, Microbiology, GMCALaboratory Diagnosis Specimen sputum, BAL, pus & crusts from granulomatous lesions, biopsy

    Direct ExaminationWet mount - KOH, CFW - round refractile yeast cells 2-10 to 30 - single or chain of cellsTissue stains HE, GMS

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAFungal CultureSDA, BHIA & BA incubated at 25 & 37C.At 25C colonies are white to tan in colour,with a yellowish-brown reverse LPCB - mycelia bearing conidia & numerous intercalary chlamydospores.

    37C off-white to cream, rough to pasty. LPCB- spherical mother cell surrounded by multiple thin-necked daughter cells: Mariners wheel

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCA Treatment & ProphylaxisLong term therapyReviewed periodically as relapses are frequentAMB combined with sulfonamidesOral Itraconazole

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCACANDIDIASISCommonest fungal disease in humansAffects mucosa, skin, nails & internal organs - superficial and deep infectionsCaused 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

  • 17/12/07Dr Ekta, Microbiology, GMCAEpidemiologyPredisposing factors Natural receptive states like infancy, old age, pregnancy. Changes in local bacterial flora 2 to antibiotics. Endocrine diseases like DMSevere chronic underlying debilitated conditions Malignancy Drugs steroids, immunosuppressants & chemotherapeutic agents. Trauma, burns or injury.

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAPathogenesis & 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

  • 17/12/07Dr Ekta, Microbiology, GMCAClinical Classification of Candidiasis

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAMucocutaneous ManifestationsOral 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

  • 17/12/07Dr Ekta, Microbiology, GMCACutaneous ManifestationsIntertriginous 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

  • 17/12/07Dr Ekta, Microbiology, GMCAClinical forms of Candidiasis in HIV patientsAsymptomatic oral carriage Oropharyngeal thrushAngular cheilitisLeukoplakia OesophagitisLaryngitis Vulvovaginitis, balanitisAcute atrophic erythemaHematogenous dissemination

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCALaboratory DiagnosisClinical specimens are collected depending on the site of involvement.

    Direct ExaminationWet mount KOH - Yeast cells, 4-8 with budding & pseudohyphae Grams stain gram +ve budding yeast cells

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAFungal CultureSDA & other bacteriological media Colonies appear in 2-3 days.Creamy white, smooth & pasty.

    Identification of species using Tetrazolium reduction medium (TRM)CHROM agar

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAC.tropicalisC.kruseiC.albicansCHROM Agar

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAGerm tube test Culture is treated with sheep or normal human serum.Incubated at 370C for 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

  • 17/12/07Dr Ekta, Microbiology, GMCACANDIDA GERM TUBE

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCAChlamydospore formation Cornmeal agar or Rice starch agarIncubated at 250cLarge, highly refractive, thick walled chlamydospores after 2-3 days of incubation.

    Biochemical testsSugar fermentation Sugar assimilation

    Dr Ekta, Microbiology, GMCA

  • 17/12/07Dr Ekta, Microbiology, GMCATreatment & ProphylaxisCorrect 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