Fungi Flashcards
(108 cards)
1
Q
Mycology
A
Study of fungi
2
Q
Fungi Kingdom
A
Eumycota
3
Q
Fungi are _ organisms
A
Eukaryotic
4
Q
Cell membranes are composed of
A
ergosterol
5
Q
Cell walls are composed of
A
Glucans, chitin
6
Q
Fungus metabolism
A
Heterotrophic
7
Q
Bacteria characteristics
A
Prokaryotes
Cell membrane- proteins, phospholipids
Cell wall- peptidoglycan, LPS
Metabolism- heterotrophic
8
Q
Human characteristics
A
Eukaryotes
Cell membrane- cholesterol
Cell wall not present
Metabolism- heterotrophic
9
Q
Plant characteristics
A
Eukaryotes
Cell membrane- sterols
Cell wall- cellulose
Metabolism- autotrophic
10
Q
2 types of fungi
A
Yeast
Mold (fleshy fungi-mushroom, filamentous molds)
11
Q
Dimorphic
A
Can be yeast or mold depending on environmental conditions
12
Q
Yeast morphology
A
Unicellular
Non-filamentous (budding, pseudohyphae)
13
Q
Budding yeast with pseudohyphae are
A
Candida species (gram +)
14
Q
Molds morphology
A
Multi-cellular
Filamentous (hyphae, can be septate or non-septate)
Interwoven hyphae form mycelium
Reproductive structures (basidium-fruiting bodies, conidia-spores)
15
Q
Stain for fungi
A
Lactophenol cotton blue stain
16
Q
Dimorphic fungus morphological
A
Mold (room temperature in the environment)
Infectious through inhalation of spores
Yeast (body temperature, diagnostic form)
Not infectious
17
Q
Systemic disease caused by Dimorphics
A
Blastomycosis- Blastomyces dermatitidis
Coccidioidomycosis-Coccidioides immitis
Histoplasmosis- Histoplasma capsulatum
Tararomyces- Talaromyces (Penicillium) marneffei
18
Q
Laboratory diagnosis involves
A
Direct detection
Culture isolation
Identification
Molecular
Serological
19
Q
Direct detection from Specimen
A
Gram stain
KOH preparation
Wet mount
Wood’s lamp
India ink stain
Histopathology
20
Q
Gram staining
A
Yeast- stain gram +
Molds stain poorly
21
Q
KOH preparation
A
Keratinized tissues (skin, hair, nails)
Look for Dermatophytes (skin infections)
Cutaneous yeast
22
Q
Wood’s lamp
A
Hair
Dermatophytosis (ringworm)
23
Q
Wet mount
A
Oral or vaginal secretions
Budding yeast
Thrush
24
Q
India ink
A
Cerebral spinal fluid
Encapsulated yeast
Cryptococcosis (Cryptococcosis neoformans)- encapsulated yeast
25
Histopathological
Gomori’s methenamin silver (GMS) stain
Mold hyphae
Detect: Aspergillosis (mold infection) , Mucormycosis/Zygomycosis, Invasive Candidiasis
26
Sabouround dextrose agar
Low pH, nutritionally deficient
2+ days for yeast
7+ days for mold
can take 4+ weeks
27
Blastoconidium
Produced by yeast cells
“Budding”
Seen in all yeast species
28
Biochemical testing
Candida albicans (Germ test tube, 2-3 hr incubation, lateral hyphae extension=positive result)
Other yeast ID methods: biochemical tests, MALDI-TOF MS
29
Mold identification
Macroscopic characteristics (culture growth)
Microscopic (hyphae structures, reproductive structures)
30
MALDI-TOF fungal ID
Identify unique species protein in yeast
31
Detection of fungal antibodies
In serum
Not reliable
Not useful in immunocompromised
32
Detection of fungal antigens
Latex agglutination (cryptococcal antigen in CSF)
Serum glactomannan (aspergillosis)
33
Culture confirmation
Nucleic acid probes (Histoplasma capsulatum, Blastomyces dermatitidis, Coccidioides immitis/posadasii)
Sequence analysis comparison
Positive blood culture bottle
Bio fire BCID2 panel
34
True fungal pathogens infect
Normal immune system
35
Opportunistic fungus affects
Immunocompromised
36
Fungus pathogenesis
Colonize host
Find suitable environment
Avoid host defense
Multiply
37
Fungal virulence factors
Thermotolerance
Adhesion (cell surface receptors, biofilm formation)
Growth (use host nutrients)
Immune evasion (capsule, intracellular survival in phagocytes)
38
How do fungi damage host tissues
Extracellular enzymes (keratinases, phospholipids, urease)
Toxic metabolites (toxins)
Immune overreaction (cytokine storm)
39
Mycetismus
Poisoning by ingestion of mushroom
40
Mycotocicosis
Intoxication by eating food contaminates with mycotoxin (aflatoxin poisoning, psilocybin intoxication)
41
Fungal hypersensitivity disease
Inhalation of fungal elements induces immunological response (contact dermatitis, Hypersensitivity pneumonitis, farmers lung, allergic bronchopulmonary)
42
Mycoses
Infection caused by fungus
43
Candida auris
Concerns of multi drug resistance
44
Fungal infections
Slower growing than bacteria
Endogenous or exogenous
Often infect immunocompromised patients
Classification based on appearance and reproductive mechanism
45
Fungal cells are _
Eukaryotic
46
Antifungal medications target
Fungal cell wall and membrane (chitin and beta 1,3 glucan-target for diagnostic testing and medications, ergosteral- another drug target)
47
Yeast
Round or oval
Budding reproduction
48
Filimentous fungi
Molds
Tubular appearance (hyphae)
Brow through branching and extension
49
Dimporphic
Yeast in humans
Mold in labs
50
Yeast
Round smooth colonies
Stain gram +
51
Risk factors for Candida infection (part of endogenous human flora)
Neutropenia
Antibiotics
Uncrotrolled diabetes
HIV
52
Mucosal Candidiasis
Orthopharyngeal: thrush, pseudomembrane
Esophageal: difficulty swallowing
Cutaneous: skin fold or moist areas
Vaginitis: burning, itching, cottage-cheese live discharge
53
Candidiasis localized organ infection
UTI: caused by cantamination from skin
Peritonitis (intraabdominal infection): after abdominal surgery or bowel perforation
CNS infection: following intracranial surgery (such as shunt placement)
54
Candidemia
candida in the blood
55
Hepatospenia Candidiasis
liver/spleen
56
Osteoarticular candidiasis
bone/joint infection
57
Endophthalmitis candida
inta-ocular infection
58
Endocarditis Candida
heart valve
59
Most common species causing Candida infection
Candida albincans (treated with fluconazole)
60
Diagnosis of Candida
mucocutaneous: based on physical exam
organ or systemic: cultures, Germ tube (used in C albicans cultures postive for yeast), Assay for 1,3 beta D glucan (detected in fungal cell wall)
61
Diagnosis of Cutaneous, Orthopharyneal
clinical appearance, wet mount
treat with topical agents (nystatin, clotrimazole or for sever infection azoles, echinocandin)
62
Diagnosis for esophagitis candidiasis
dysphafia or adynophagia
diagnosis with endoscopy
treat with azoles or echinocandin
63
Urinary tract Candidiasis
assiciated with urinary instrumentation
Remove catheter, may also use azole or amphotericin B
64
Disseminated Candidiasis/Candidemia
blood cultures
1,3 beta D glucan assay
65
Endophthalmitis candidiasis diagnosis
dialated retinal exam
66
Endocarditis candidiasis diagnosis
blood culture and echocardiogram
67
Cryptococcus infection
most common fungus causing meningitis
inhaled yeast from environment
C. neoformans: bird droppings
C. gatti: trees (eucalyptus) in west coast
68
Risk factors for Cryptococcus infection
HIV/AIDs
69
Cryptococcus pathogenesis
yeast cells surrounded by thick polysaccharide *capsule (allows growth, prevents phagocytosis, supress immune response, interference with antigen presentation, adherance)
Melanin (produced and deposited in cell wall- integrity, protection from phagocytosis/oxidation/temperature extremes)
70
Cryptococcus spectrum of disease
Respiratory tract (asymtomatic to pneumonia)
CNS (meningitis, cryptococcoma)
Disseminated (fungemia)
71
Diagnosis of Cryptococcus
Pneumonia: look for nodule, Serum cryptococcal antigen detects polysaccharide capsule
CNS: CSF cryptococcal antigen, India ink stain
Disseminated: serum cryptococcal antigen, need LP to evaluate for CNS involvement
72
Pneumocytosis jjirovecci
protozoa
oppertunistic infection in immunocomprimised
HIV with CD4<200
prolonged steroid use
aquired through inhalation
likely aquired during childhood and reactivated during immunisupression
73
Pneumocystis jirovecci causes
diffuse bilateral pneumoia
starts with dry couch/difficulty breathing/hypoxia
causes chronic lung damage with cytic changes
74
Pneumocystitis diagnosis and treatment
Cannot be cultured
identified using GMS stain
elevated 1,3 beta-D-glucan
Treatment: high dose Bactrim
reverse immunocompromising state
75
Malassezia furfur clinical syndromes
Cutaneous infection: Pityriasis (tinea) versicolor
hypo (patients with dark skin) or hyperpigmented (patients with light skin) scalded macules interfering with melanin production
76
Malassezia furfur diagnosis
Skin scraping with KOH prep (spaghetti and meatballs yeast)
Skin lesions fluorescence with wood lamp
Culture requires lipids to grow (add olive oil to culture)
77
Malassezia furfur treatment
Cutaneous: topical agents
Systemic (Fungiemia): catheter removal, systemic treatment
78
Dermatophytes
Cause human disease (ringworm)
Keratinolytic (break down skin, hair, nails)
79
Tinea capitis
Infection on head and face
80
Tinea barbae
Beard and facial hair
81
Tinea corporis
Body
82
Tinea pedis
Foot
83
Tinea cruris
Groin
84
Tinea unguium
Toenails, fingernails
85
Dermatophytes diagnosis and treatment
Clinical appearance
Wood lamp flouresence
Skin/nail scraping with KOH
Culture on Sabouraud agar
Treatment: topical agents
86
Dimorphic
Histoplasma
Blastomyces
Coccidiodes
Sporothrix
Present in soil (inhalation or direct inoculation)
Primary pathogen in immunocompetent
87
Histoplasmosis capsulatum
Found in chicken and bat droppings
Conidiophores inhaled and transform to yeast cells
Yeast cells are ingested by macrophages leading to an increase in PH residing efficacy of lysosomal enzymes
Proliferate and destroy macrophages
88
Histoplasmosis diagnosis and treatment
Culture on Sabouraud agar
Narrow based budding yeast
Cytology with yeast forms via GMS Giemsa or PAS stains
Detection of Histoplasma antigen
89
Blastomycosis pathogenesis
Grows as hyphal form in environment
Canidia released and transform into yeast within respiratory tract
90
Blastomyces pathogenesis
Resist phagocytosis by modifying cell wall composition (shed WI-which activates immune response)
Proliferation in tissues and invasion into blood stream
91
Blastomycosis
Pneumonia
Cutaneous (disseminated infection or direct inoculation)
Bone
CNS
92
Blastomycosis diagnosis
culture on sabouraud agar
Look for broad based budding yeast
Blastomyces antigen detection
93
Blastomycosis treatment
Mild cases do not require treatment
94
Coccidioidomycosis
Live in desert soil
produce ammonia to create alkaline environment
Hyphae fragment into conidia, inhaled
95
Coccidioidomycosis pathogenesis
Develop into spherules which produce endospores
Less susceptibile to phagocytosis due to urease production
Can enter bloodstream
96
Coccidioidomycosis disease spectrum
Valley fever
May reactive during immunosuppression
Pneumonia
Meningitis
Cutaneous
97
Coccidioidomycosis diagnosis and treatment
Culture is insensitive
Coccidioides antigen
Cytology with yeast forms
Serology: EIA
Immunocompetent people don’t usually require treatment
Fluconazole for moderate infection
98
Saporothrix schenckii
Soil and decaying plant matter
Direct inoculation into skin
Associated with rose gardeners
Causes chronic nodular ulcerative lesions and spreads via lymphatics
99
Sporotrichosis diagnosis and treatment
Culture
Cytology (cigar shaped yeast)
Treatment with potassium iodine
100
Filamentous Fungi
Aspergillus species
101
Pathophysiology of Mold infection
Conidia inhaled and invade respiratory
Attach to epithelium
Conidia swell and germinate in alveoli
Hyphae spread through lung parenchyma and blood vessels causing hemorrhage and necrosis
102
Aspergillus species
Inhaled from environment (decomposing plants, soil, moist environments)
Profound neutropenia and prolonged steroid use is a risk factor
103
Aspergillis disease
Allergic bronchopulmonary aspergillosis
Pneumonia
Invasive sinusitis
Cerebral aspergillosis
104
Aspergillis diagnosis and treatment
Imaging test
Galactomannan (Aspergillis antigen) in serum
1,3 beta D glucan
PCR
Histopathology- septate, acute angle branching
Treatment- Voriconazole
105
Mucormycosis
*Rhizopus, *Mucormycosis, Lichtheimia, Cunninghamella, Absidia, *Rhizomucor
Inhaled from environment
Risks profound neutropenia, diabetics, steroid use
106
Mucormycosis Diseases
Rhino-orbital cerebral disease (fungal sinusitis)
Pulmonary
Cutaneous necrotizing fasciitis and necrotic lesions
GI (premature neonates)
107
Mucormycosis Disease and Treatment
High mortality
Clinical presentation
Glactomannan and 1,3 Beta-D-glucan= negative
Culture and histopathology (pauci-septate, ribbon-like, right angle branching)
Treatment: surgical debridement, reversing immunocompromising conditions
108
What mold has septate hyphae
Aspergillus
