Systemic Mycoses

Systemic mycoses

 Dimorphic  Systemic  Endemic  All

causes pulmonary infections

 Histoplasmosis  Blastomycosis  Coccidioidomycosis  Paracoccidioidomycosis  Penicilliosis

marneffei

Histoplasmosis  Causative  

agents – H.capsulatum var capsulatum H.capsulatum var duboisii

Morphology  Both the varieties are thermally dimorphic ie as mould in nature and in culture at 250C and as an intracellular budding yeast in tissue and in culture at 370C  MOULD –white or brown hyphal colonies;two types of conidia –tuberculate macroconidia and small oval microconidia  YEAST-small oval budding yeast for capsulatum and larger budding yeast for duboisii

 Yeast

phase

Pathogenesis Geographical regions Histoplasma cap var cap the eastern half of US ,Latin America  Histo cap var dub Tropical areas of Africa Source- soil containing bird feces Mode of acquisition –inhalation 

The microconidia which is inhaled is converted to the yeast phase within the pulmonary macrophages (reticuloendothelial cells) Clinical syndromesVar capsulatum    

Large majority of infections are asymptomatic In some acute pulmonary histoplasmosis- flulike illness In a few ,lymphadenopathy ,arthritis ,mediastinal fibrosis In a very few ,disseminated histoplasmosis –higher in children and immunocompramised adults -weight loss, oral ulcers , hepatosplenomegaly, anemia, fever

var duboisii-African histoplasmosis -Pulmonary lesions are uncommon -Lesions of skin and bone -disseminated form only in the immunodeficient marked by fever, lymphadenopathy, anemia

Lab diagnosis Specimens Blood ,bone marrow, scrapings from lesions, urine, BronchoAlveolarLavage, tissue, sputum Microscopy-Giemsa, PAS demonstrates the yeast phase Culture-on Sabouraud’s agar -presence of tuberculate spores diagnostic Serology-Ag AND antibody detection-CF,ID,EIA 

 TREATMENT

Amphotericin B followed by oral itraconazole

Blastomycosis  Causative

agent –Blastomyces dermatitidis  Dimorphic fungus  Also called North American Blastomycosis

Morphology Exist as mould at 25oC and as yeast in tissue and in culture at 37oC MOULD –white to tan filamentous colonies with conidia located on hyphal branches YEAST-spherical and reproduce by the formation of blastoconidia .The buds are single and attached to the parent cell by broad bases 

 Mycelial

form

 Yeast

phase

 Pathogenesis  Geographic

distribution-North America (ohio and Mississippi river valleys ),Africa  Source decaying organic matter  Mode of acquisition –inhalation of conidia

 



Clinical syndromespulmonary blastomycosis -asymptomatic or mild flu like illness; Primary infection in the lung and may resemble tuberculosis or histoplasmosis. From the lungs the fungus spreads and form multiple abscesses in various parts of the body. The ulcerative lesions are usually on the skin of the face or other exposed parts

 Lab

diagnosis  Specimens –sputum,BAL,pus ,skin scrapings ,tissue  Microscopy –GMS,PAS,Giemsa –typical broad based budding yeast forms  Culture-Mycelial form has to be converted to the yeast at 370C

 TREATMENT Amphotericin

B,ITRACONAZOLE

Coccidioidomycosis  Causative

agents-Coccidioides immitis,C.posadasii

 Morphology

– MOULD –INITIALLY white to gray then matures to brown or lavender;the vegetative hyphae fragment into arthroconidia YEAST-endosporulating spherule

 Mycelial

form

 Yeast

phase

 Pathogenesis

–  Geographical distribution-south western US,northern mexico  Source –soil,rodents  Mode of acquisition-inhalation of arthroconidia

  

In most cases asymptomatic infection results Many persons develop influenza like fever Less than one percent develop ,chronic disseminated disease(coccidiodal granuloma)

 Lab

diagnosis Specimens –sputum,BAL,tissue  Microscopy –KOH ,H and E,GMS,PASendosporulating spherules  Culture –  Serology –ID,LA,CF

 TREATMENT Amphotericin

B,ITRACONAZOLE

Paracoccidioidomycosis  Causative

agent-Paracoccidiodes brasiliensis  Also called South American blastomycosis

 MORPHOLOGY  MOULD

–white colonies,also brownish colonies –septate hyphae with chlamydoconidia  YEAST-oval to round yeastlike cells, multiple buds (blastoconidia )-mariners or pilot wheel

 Mycelial

phase

 Yeast

phase

 Pathogenesis  Geographical

distribution –south America  Source soil likely  Mode of acquisition –inhalation or inoculation

 Clinical

syndromes May be asymptomatic  Pulmonary forms o A chronic granulomatous disease of the skin, mucosa, lymph nodes and internal organs

 Lab

diagnosis Specimens –sputum, BAL, Scrapings of ulcer, pus, CSF, Tissue  Microscopy –calcofluor fluorescence,H and E,GMS-Charac. Multiple budding yeasts  Culture  Serology –ID ,CF

 TREATMENT Itraconazole

,amphotericin B