50

Click here to load reader

Systemic mycoses

Embed Size (px)

Citation preview

Page 1: Systemic mycoses

SYSTEMIC MYCOSES

Wednesday, January 11, 2012

Page 2: Systemic mycoses

large multiple budding yeast

similar to B. dermatitidisParacoccidiodomycosisP a r a c o c c i d i o i d e s

spherule (10-20 u) with endospores

septate mycelium fragment to arthroconidia; colonies are buff or white and moth

CoccidioidomycosisCoccidiodesimmitis

small single budded yeast

septate mycelia microconidia; tuberculate macroconidia colonies are white and buff

HistoplasmosisHistoplasma capsulatum

budding yeast with broad base budseptate mycelium; conidia are

pyriform, globose or double colonies are white or beige, fluffly or glaborous

BlastomycosisBlastomyces dermatitidis

PARASITIC PHASESAPROPHYTIC PHASEDISEASES AND ETIOLOGIC AGENT

SUMMARY OF DEEP MYCOSES

Wednesday, January 11, 2012

Page 3: Systemic mycoses

Monomorphic

No change in form/state in response to stimulus like temperature. Example, yeast at 25° C and 37° C

Examples: Mycelium = Aspergillus species; Yeast = Cryptococcus species

Dimorphic

Change in form in response to stimulus like temperature. Example yeast at 37° C and mycelium at 25° C

Examples: Histoplasma capsulatum; Blastomyces dermatitidis; Paracoccidiodes brasiliensis; Coccidiodes immitis

CHARACTERISTICS TO REMEMBER

Wednesday, January 11, 2012

Page 4: Systemic mycoses

Temperature

Oxidation-reduction potential

Availability of sulfhydril groups

CO2 tension

FACTORS AFFECTING DIMORPHISM

Wednesday, January 11, 2012

Page 5: Systemic mycoses

Dimorphic

Mycelial phase: 25° C

Macroconidia (8-14μm)

Microconidia (2-4μm)

Histoplasma capsulatum

Wednesday, January 11, 2012

Page 6: Systemic mycoses

At 37°C or at body temperature = budding yeast 2-3 x 3-4 μm

Found predominantly in histiocytes

Histoplasma capsulatum

Wednesday, January 11, 2012

Page 7: Systemic mycoses

soil with high nitrogen content, associated with the guano of bats and starlings

rotting guano mixed with soil & feathers of the birds

open environment, soil is nitrogen rich with a rainfall of 35-50 inches and 67-87% relative humidity

caves, the main habitat of bats, which are the reservoir of Histoplasma capsulatum

LIFE CYCLE

Wednesday, January 11, 2012

Page 8: Systemic mycoses

LIFE CYCLE

Wednesday, January 11, 2012

Page 9: Systemic mycoses

CLASSIFICATION OF HISTOPLASMOSIS

TYPE OF INFECTION

SPECIFIC DISORDER COMMENTS

Normal Hosts

• Asymptomatic or mild like flu illness

• Occurs with normal exposure

Normal Hosts• Acute pulmonary

histoplasmosis• Occurs with

heavy exposureNormal Hosts

• Rare complications

• Pericarditis, mediastinal fibrosis

Wednesday, January 11, 2012

Page 10: Systemic mycoses

CLASSIFICATION OF HISTOPLASMOSIS

TYPE OF INFECTION

SPECIFIC DISORDER COMMENTS

Opportunistic Infection

• Disseminated histoplasmosis

• Occurs in individuals who have an immune defectOpportunistic

Infection• Chronic

pulmonary histoplasmosis

• Occurs in individuals who have a structural defect

Wednesday, January 11, 2012

Page 11: Systemic mycoses

CLASSIFICATION OF HISTOPLASMOSIS

TYPE OF INFECTION

SPECIFIC DISORDER COMMENTS

Opportunistic Infection

• Disseminated histoplasmosis

• Occurs in individuals who have an immune defectOpportunistic

Infection• Chronic

pulmonary histoplasmosis

• Occurs in individuals who have a structural defect

Wednesday, January 11, 2012

Page 12: Systemic mycoses

CLINICAL FORMS & SYMPTOMS

TYPE OF INFECTION SPECIFIC DISORDER

Primary acute

• Asymptomatic or flu-like syndrome

Primary acute • Chest pain, shortness of breath and hoarsenessPrimary acute• Radiologically, discrete lung lesion may or may not develop

Chronic cavitary

• Large pulmonary lesions develop

Chronic cavitary • lesions may exist in a relative quiescent stateChronic cavitary• Often mistaken for tuberculosis

Severe disseminated

• Only small percentage progress into this clinical forms

Severe disseminated • Disease of reticuloendothelial system in which organs infection may developSevere disseminated

• In massive dissemination, it could be fatal

Wednesday, January 11, 2012

Page 13: Systemic mycoses

HISTOPLASMOSIS

Wednesday, January 11, 2012

Page 14: Systemic mycoses

Direct Examination: KOH; Wright/Giemsa

Culture: SDA; Smith and Goodman (for contaminated specimen); Yeast Extract = place the CM in a plastic bag

LABORATORY DIAGNOSIS

Wednesday, January 11, 2012

Page 15: Systemic mycoses

Skin test with histoplasmin Ag

CF test

Immunodiffusion test

LABORATORY DIAGNOSIS

Wednesday, January 11, 2012

Page 16: Systemic mycoses

Amphotericin B for disseminated infection

Itraconazole for immunocompromised patients

Cleaning of bat droppings

TREATMENT & PREVENTION

Wednesday, January 11, 2012

Page 17: Systemic mycoses

2 phases: asexual & sexual

Blastomyces dermatitidis (asexual phase)

Ajellomyces dermatitidis (sexual phase)

Dimorphic fungus

Blastomyces dermatitidis

Wednesday, January 11, 2012

Page 18: Systemic mycoses

MYCELIAL FORM

The mycelial phase at 25° C showed typical pyriform microconidia , which are about 2-4 microns in diameter.

YEAST FORM

At 37° C and at body temperature, this organism is a yeast 8-15 microns in diameter.

Buds are produced singly and are attached to parent cell by broad base.

Blastomyces dermatitidis

Wednesday, January 11, 2012

Page 19: Systemic mycoses

LIFE CYCLE

The mode of transmission: inhalation of the spores or the microconidia

Natural habitat: remains an enigma

Favors environment with high nitrogen content, acid pH, abundant moisture, and perhaps enriched with animal excreta

Wednesday, January 11, 2012

Page 20: Systemic mycoses

LIFE CYCLE

Wednesday, January 11, 2012

Page 21: Systemic mycoses

BLASTOMYCOSIS Chicago Disease = Gilchrist’s disease = North American Blastomycosis

Wednesday, January 11, 2012

Page 22: Systemic mycoses

• Indicates systemic disease• May result from direct inoculation from

the soil

Cutaneous

• Extension of pulmonary form• Common sites of involvement are liver

and spleen• Granulomatous lesions are present

Systemic

• Fever, cough and hoarseness• Productive cough, fever and weight loss

after several months• Radiographically resembles tuberculosis

Pulmonary

SYMPTOMSCLINICAL FORMS

Wednesday, January 11, 2012

Page 23: Systemic mycoses

Blastomycin• Has a tendency of high cross reactivity• Little diagnostic value

3. Skin Test

Saborauds, Mycosel or Mycobiotic Agar• Fluffy, whitish brown fungus with pyriform

spores• Culture is not routinely done

2. Culture

20% KOH• specimen is sputum for pulmonary form

and skin for cutaneous form• Biopsy material can also be used• Look for the presence of broad based

buds

1. Direct Microscopic

IMPORTANT FEATURESTESTS

Wednesday, January 11, 2012

Page 24: Systemic mycoses

Wednesday, January 11, 2012

Page 25: Systemic mycoses

TREATMENT & PREVENTION

Amphotericin B has been used but with erratic results

2-hydroxystilbamidine

Ketoconazole, less nephrotoxicity

Prevent fomite inhalation in endemic area

Wednesday, January 11, 2012

Page 26: Systemic mycoses

Coccidioides immitis

Amphotericin B has been used but with erratic results

Asexual phase: Coccidiodes immitis

Sexual phase: not known

MYCELIAL STAGE (25°C)

septate hyphae mature in a manner such that alternate cells develop into arthroconidia being separated by vacuolized cells

arthroconidia separate readily and have a “barrel” shape appearance

Wednesday, January 11, 2012

Page 27: Systemic mycoses

Coccidioides immitis

Wednesday, January 11, 2012

Page 28: Systemic mycoses

Coccidioides immitis

YEAST FORM

In tissue and at body temperature:

Develops into spherules (sporangia; 10-60μm) filled with endospores (2-5μm)

Wednesday, January 11, 2012

Page 29: Systemic mycoses

LIFE CYCLE

Wednesday, January 11, 2012

Page 30: Systemic mycoses

COCCIDIOMYCOSIS

Posada’s Disease = San Joaquin Valley Fever = Desert Rheumatism

TREATMENT & PREVENTION

Generally difficult to manage regardless of drug use

Amphotericin B is the drug of choice

Itraconazole and fluconazole have been tried with little success

Prevent spores inhalation

Wednesday, January 11, 2012

Page 31: Systemic mycoses

• 1 in 500 patients progressed into this state

• Fungi spreads into various organs• Prognosis is grave

Disseminated Form

• Precipitin and complement fixation titers appear

• Development of well defined lung cavitation

• Exist for years and could be unnoticed

Benign Form

• Occurs 7-28 days after inhalation of single spore

• Positive skin test• Flu-like fever, malaise and cough• 10% develop erythrema nodosum or

erythrema multiforme

Primary Pulmonary

SYMPTOMSCLINICAL FORMS

Wednesday, January 11, 2012

Page 32: Systemic mycoses

Skin test• conversion back to skin test positive (anergy) is an

indication of grave prognosis

3. Others

Saboraud’s medium with or without antibiotics• room temperature, white fluffy fungus• arthrospores are dangerous to work with• Never try the organism in the petri dish but always

on the bottle or test tube• Examine on the 3rd or 4th day, but must kill

organisms with formalin before attempting to make an LPCB mount

• Can prepare exoantigen

2. Culture

10-20% KOH• sputum, tissue or skin are used as specimen• look for the presence of spherules

1. Direct Microscopic

IMPORTANT FEATURESTESTS

Wednesday, January 11, 2012

Page 33: Systemic mycoses

Wednesday, January 11, 2012

Page 34: Systemic mycoses

Paracoccidioimycosis brasiliensis

Dimorphic

Mycelial stage (25°C): no typical sporulation

Yeast stage (37°C): with several budding cells attached to the parent cell, some in a “mariner’s wheel” arrangement

about 2-30μm

Wednesday, January 11, 2012

Page 35: Systemic mycoses

LIFE CYCLE

Transmitted by inhalation of the spores

Restricted to South and Central America

Isolated in acidic soil and its growth requires increased humidity

natural habitat remains to be elucidated

Wednesday, January 11, 2012

Page 36: Systemic mycoses

Wednesday, January 11, 2012

Page 37: Systemic mycoses

PARACOCCIDIODOMYCOSIS

South American Blastomycosis = Lutz-Splendore-Almeida’s Disease

A chronic granulomatous disease of skin, mucous membranes, lymph nodes and internal organs

Central and South America more specifically in Brazil

Wednesday, January 11, 2012

Page 38: Systemic mycoses

PARACOCCIDIODOMYCOSIS

Females are as susceptible to infections as males, but the incidence of clinical disease in males is nine times higher

Primary pulmonary disease is often inapparent

Disseminated disease often causes ulcerative lesions of the buccal, nasal and occasionally gastrointestinal mucosa.

Wednesday, January 11, 2012

Page 39: Systemic mycoses

Dr. Supachai Basit

• Paracoccidioidin skin test• Complement fixation test• Immunodiffusion test

3. Others

Saboraud’s • At room temperature it grows a non

spore forming septate fungusBrain Heart Infusion at 35° C• It produces yeast that is seen in tissue

2. Culture

10-20% KOH• 1-2 drops are used• demonstration of multiple budding yeast

1. Direct Microscopic

IMPORTANT FEATURESTESTS

Wednesday, January 11, 2012

Page 40: Systemic mycoses

TREATMENT & PREVENTION

Amphotericin B

Itraconazole

Long term therapy is required

Prevent inhalation of dust in endemic area

Wednesday, January 11, 2012

Page 41: Systemic mycoses

Cryptococcus neoformans

Monomorphic: always in yeast form whether at 25° or at 37° C.

Unique feature: acidic mucopolysaccharide capsule

Wednesday, January 11, 2012

Page 42: Systemic mycoses

LIFE CYCLE

The etiologic agent of cryptococcosis has been recovered in large numbers from the excreta

debris of pigeon roosts, thus it appears to survive well in a dessicated, alkaline, nitrogen-rich and hypertonic environment

There is a close relationship to the habitats of pigeon, but the organism does not infect the bird

Wednesday, January 11, 2012

Page 43: Systemic mycoses

Dr. Supachai Basit

Wednesday, January 11, 2012

Page 44: Systemic mycoses

CRYPTOCOCCOSIS

Busse-Buschke’s Disease, Torulosis, European Blastomycosis

The disease is worldwide in distribution.

This yeast has been repeatedly isolated from sites inhabited by pigeons, particularly their roosts and droppings.

Pigeons are not naturally infected. Wednesday, January 11, 2012

Page 45: Systemic mycoses

CRYPTOCOCCOSIS

Primary pulmonary cryptococcosis is usually inapparent but may be chronic, subacute or acute.

The clinical entity is most often seen in cryptococcal meningitis.

Osseous and cutaneous disease can be present without apparent neurologic involvement.

Wednesday, January 11, 2012

Page 46: Systemic mycoses

CRYPTOCOCCOSIS: CUTANEOUS FORM

Wednesday, January 11, 2012

Page 47: Systemic mycoses

CRYPTOCOCCOSIS: NEUROLOGIC FORM

Wednesday, January 11, 2012

Page 48: Systemic mycoses

Dr. Supachai Basit

Latex Agglutination TestUrease Test Positive

3. Others

Saboraud’s medium with or without antibiotics

• either at room temperature or at 35° C, the colonies develop after 1-3 weeks incubation as shiny, slimy, light tan yeast colonies

2. Culture

India Ink Stain• Cerebrospinal fluid (CSF) is used as

specimen• The organisms appear as yeast about

8-12 microns in diameter, which are usually surrounded by clear capsules

1. Direct Microscopic

IMPORTANT FEATURESTESTS

Wednesday, January 11, 2012

Page 49: Systemic mycoses

IN CULTURE

Wednesday, January 11, 2012

Page 50: Systemic mycoses

TREATMENT & PREVENTION

Amphotericin B in combination with 5-fluorocytosine have been successful

Fluconazole is as effective too

Clean pigeon droppings

Avoid visiting caves without protective gears

Wednesday, January 11, 2012