Fungi

organisms that live on dead or decaying matter

Cell wall rigid & composed of chitin & glucan

Ergosterol is substituted for cholesterol

Long, branching filamentous cells of fungus

Asexual, non-motile spores of fungus. Can form at the tips of the growing hyphae on a specialized structure called a conidiophire

unicellular

Multicellular

Asexual, formed from fragmentation of septated hyphae into single cells

Asexual, Thick-walled spore, formed by rounding and enlargement within hyphael segment

asexual, Endospores inside spherules (sporangia) in tissue

Non septated hyphae, Zygomycota

Dimorphic Ascomycota

Yeastlike Ascomycota

septated hyphae, Ascomycota

Septated hyphae, Ascomycota

Septated hyphae, Ascomycota

Septated hyphae, Ascomycota

Septated hyphae, Basidiomycota

Thermal (exist as yeasts or spherules at 37° C and molds at 25° C)

Malassezia furufr

Tineas- ringworms

Trychophyton rubrum

Sporothrix schenckii

Cryptococcus neoformans

Dimorphic. Infection is by inhalation of aerosolized conidia (areas of moist soil, decomposing organic debris). Common infection among dogs

Blastomycosis (may resemble TB). Dissemination via infected macrophages to skin, bone, urinary tract, CNS in immunocompromised.

Dimorphic. Giemsa stain. Most common pulmonary and systemic mycosis of humans.

1.Large (8 to 15 μm), thick-walled, spherical macroconidia with spikelike projections (tuberculate macroconidia) that arise from short conidiophores

2.small, oval microconidia (2 to 4 μm) with smooth or slightly rough walls that are sessile or on short stalks

in soils w/ high nitrogen content, Especially areas contaminated w/ bird or bat droppings. Multiples in phagolysosome & lyse host cell.

Flulike illness w/ fever, chills, headache, cough, myalgias, chest pain. Mediastinal lymph node enlargement (can lead to mediastinal fibrosis) occurs in most pts. Usually resolves w/ supportive care, but can progress to acute respiratory distress syndrome

most likely to affect pts w/ underlying disorders of cell-mediated immunity. Mucocutatneous lesions & hepatosplenomegaly are common.

Dimorphic. Inhalation. Mold, infectious arthroconidia

California, found in soil late summer/early fall (dusty season)

desert southwestern US, northern Mexico, and scattered areas of central and South America. Found in soil late summer/early fall (dusty season)

Valley Fever: asymptomatic, self-limited flulike illness marked, Allergic rxn, Erythema nodosum (red nodules)

progressive pulmonary disease w/ nodules, cavitary disease. Lesions tend to calcify as they heal. Dissemination to skin, soft tissues, bones, joints, and meninges. More likely found in 3rd tri pregnancy & immunocompromised pts.

Nucleic acid hybridization

Dimorphic. Inhalation or traumatic inoculation. Pilot's wheel.

Latin America (Brazil), children, exposure to soil, depressed cell-mediated immunity

South American blastomycosis. Dissemination frequently involves mucous membranes, skin, and lymph nodes

Lipophilic yeast. Person to person transmission of infected keratinous material. Normal to skin flora. Hair follicle- folliculitis; yeast thrives in sebaceous environment

KOH stain of skin scraping . Yeast clusters & short curved septate hyphae = “spaghetti and meatballs”. Coppery-orange fluorescence under UV, Calcofluor white, Culture (supplement with olive oil)

Dimorphic. Conidiophores arise at right angles from the thin septate hyphae and are usually solitary. Cigar-shaped yeast.

Trauma from thorns. Grows on bark of trees, shrubs, and garden plants. “rose-gardener” disease

Sporothrix schenckii

Cutaneous mycoses. microconidia are usually abundant. macroconidia absent or present in small numbers; when present, they are pencil-shaped and thin, with smooth walls

Cutaneous mycoses. multicelled macroconidia with thick, rough walls

Cutaneous mycoses. microconidia absent; macroconidia typically club-shaped, with thin, smooth walls

Trichomyton micro & macroconidia

Microsporum micro & macroconidia

Epidermophyton macroconidia

Dermatophyte infection of smooth or glabrous skin. May be caused by any dermatophyte

Dermatophyte infection of groin. Trichophyton and Epidermophytom

Dermatophyte infection of nails. Trichophyton

Microsporum and Trichophyton. sheath of conidia formed on outside of hair shaft. Conidia formed w/in hair shaft

most serious; associated w/ tinea capitis, causes permanent hair loss. Contagious

Trichophyton

Trichophyton and Epidermophytom

KOH preparation of skin or nail scrapings. Hyphae and arthroconidia in calcofluor white

Encapsulated, yeast-like. Budding. Capsule that inhibits phagocytosis & Downregulates Th1 responses

In soil, pigeon droppings (inhalation). Opportunistic infection

Acute pulmonary disease, Cutaneous Cryptococcosis, Life-threatening encephalitis or meningoencephalitis

monomorphic. Branched, septate hyphae that produce conidial heads treelike pattern of branching. branches are dichotomous and usually arise at acute (∼45°) angles

Aspergillus fumigatus

Via inhalation. air, soil, and decaying matter.

Allergic Bronchopulmonary symptoms & Allergic sinusitis. Colonization of lower airway- obstructive bronchial aspergillosis

–fungal ball, plugs composed of hyphal elements and mucinous material.

–Lung cavities

• –usually are asymptomatic; but can lead to pulmonary
• hemorrhage- need surgical removal

severely neutropenic and immunodeficient patients. necrosis and hemorrhage. Bronchial aspergillosis may cause wheezing, dyspnea, and hemoptysis. Cutaneous manifestations may occur

Chest CT scans demonstrate “halo” signs, Area infiltrate surrounding nodular densities

Candida albicans

Oval yeastlike forms that produce buds or blastoconidia and chlamydospores. Produce pseudohyphae and true hyphae. Phenotypic switching may occur

Candida hyphae & pseudohyphae

Normal commensals of diseased skin and mucosal membranes of GI, UG, and respiratory tracts. Also found in environment. Nosocomial transmission. Primary source of infection: the patient

Surface molecules that permit adherence of the organism to other structures. Acid proteases and phospholipases. phenotypic switching

• Oropharyngeal candidiasis & Hematogenous candidiasis (candida septicemia). Vulvovaginal candidiasis. Skin infections (pruritic rash with erythematous vesiculopustular lesions). GI candidiasis, Pulmonary candidiasis, Urinary tract candidiasis, Meningitis, Endocarditis, myocarditis
• & pericarditis

KOH, PAS, and GMS stains

• - trophozoite (trophic form), in which it often exists in clusters. Form inhaled; attach to alveoli
• –The uninucleate sporozoite (precystic form)
• - The cyst, which contains several intracystic bodies (spores)

Acquisition early in life; commonly found in the lungs of healthy individuals. Person-to-person spread

Pneumocystosis. Interstitial pneumonitis & Extrapulmonary manifestations

Pneumocystis

Giemsa & GMS stains. bronchoalveolar lavage (BAL) fluid in LM. Imaging.

Histoplasma macrocanidia

Coccidioides arthroconidia

Blastomyces yeast

Blastomyces yeast budding

Histoplasma yeast

Coccidoide spherule