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Microbio > Exam 2: 15-16 > Flashcards

Exam 2: 15-16 Flashcards

1
Q

DIMORPHISM

Between Yeast and Mold which is found in the heat and which is found in the cold?

Purpose is to help escape phagocytosis

A

YEAST = HEAT
MOLD = COLD

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2
Q

Dimorphism

During what phase would you find the hyphae in soil and decaying vegetation, making spores

25 C

A

SAPROBIC Phase

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3
Q

During what phase would you find yeast adapted to grow in 37 C, reproduce asexually in mucosa and escape host immunity

More rapid than hyphae and less immunogenic

A

PARASITIC Phase

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4
Q

Spores are easily phagocytosed

  1. Macrophages/Neutrophils recognize these spoers –> phagosome
  2. NADPH oxidase and iNOS activation releases what to prevent DNA replication/expression and inactivate enzymes ?
A

NADPH Oxidase and iNOS activation release ROS and RNS

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5
Q

What does the phagosome do to the pH to be fuse with the lysosome and digest microbes using acid hydrolases

A

LOWERS pH by pumping H+

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6
Q

Yeasts are resistant to phagocytosis

What do yeasts do to allow them to be resistant from phagocytosis?

A

Shed immunodominant antigen from the cell surface and modify the cell wall components to block phagocytosis

WI-1 is shed permitting blastomyces escape from phagocytosis

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7
Q

CD4+ T Cells Release ____ – recruit other cells
CD8+ T Cells Release ____ – kill pathogens and infected host

A

CD4+ T Cells Release CYTOKINES
CD8+ T Cells Release CYTOXINS

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8
Q

Which T cell respnose involves macrophage function, pro-inflammatory

A

Th1

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9
Q

Which T cell response recruits and activates neutrophils

A

Th17

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10
Q

Which T cell responses are MOST effective for fungal response?

A

Th1 and Th17

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11
Q

Which T cell response would allow fingus to evade immunity?

A

Th2 cells promote B cell, mast cell and eosinophil activation – allergy and anti inflammatory which sustains viability of the fungus

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12
Q

this saprobe is small in size and easily aerosolized so when inhaled it can access the lower respiratory tract

A

ARTHOCONIDIA

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13
Q

these have a protein covering allowing it to be antiphagocytic, therefore if taken up the conidia are not digested

A

HYDROPHOBINS

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14
Q

this coats spherule and modulates for Th2 response

A

SOWgp (SOW glycoprtein)
– favors fungal persistence

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15
Q

HISTOPLASMA CAPSULATUM

inhaled conidia spores transform into yeast –> alveolar macrophages (ingestion by phagocytes)
* pH of phagolysosome INC preventing what??

A

preventing the activation of acid hydrolases and interefering with antigen processing

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16
Q

Histoplasma Capsulatum

Alpha (1,3) glucan in the cell walls allow for what?

A

Allows for replication in phagolysosome and phagocyte lysis

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17
Q

Cryptococcus Neoformans

Encapsulated Yeast protects the fungus from phagocytosis how?

A

Negative charge of capsule repells immune cells
Blocks NO access to the fungus
Interferes with antigen processing

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18
Q

Cryptococcus Neoformans

What in the cell wall contributes to the NEG charge in the cell wall/capsule and contributes to protection form phagocytosis, NO, temp. extremes, and iron loss

A

MELANIN

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19
Q

Urease catalyzes hydrolysis of urea to yield ammonia therefore doing what to pH

Saprobe urease release – alkaline soil for optimal growth

A

INC pH – INC ALKALINITY

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20
Q

Both saprobe and parasitic forms produce proteinases during cell growth, which are responsible for the breakdown and degradation of?

A

breakdown of ECM proteins and degrade hemoglobin and IgA and IgG

allows fungus to breach respiratory mucosal barrier/ enter blood stream

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21
Q

this type of fungi produces the disease by going on/in host
Ex: Athletes Foot

A

MYCOSES

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22
Q

exposure to toxins/metabolites of toxin produces the disease

A

Mycotoxicoses

23
Q

= toxigenic fungi
- dont produce significant amount during disease
- synthesis requires a temp lower than body temp

A

MYCOTOXINS

24
Q

this toxin is found in PEANUTS, MAIZE and CORN
made when aspergillus replicates, invades crops in tropical areas

A

AFLATOXINS

25
Q

mechanism of toxin

this toxin metabolizes in the liver to an EPOXIDE whivh interfers with DNA replication and cell division

A

AFLATOXIN

26
Q

mycotoxins

seen on moldy corn
inhibits ceramide generation, INC TNF-alpha production and induces cell apoptosis

A

FUMONISMS

27
Q

mycotoxin

dark in grain kernels that can be milled into flour
Can cause VASOSPASMS – constriction (lack of O2 can cause gangrene)

A

ERGOT

28
Q

Microscopic Exam

specimen can be immediately stained with reagents
Add Stain: KOH, lactophenol cotton blue, india ink

A

WET MOUNT

29
Q

Lactophenol Cotton Blue has three components:

Phenol – kills fungi
Lactic Acid – preserves
Cotton Blue stains the ___ in the cell wall

A

stains the chitin in the cell wall

30
Q

Microscopic Exam

This stain stains the polysaccharide in fungal walls to stain bright red

A

Periodic Acid Schiff (PAS) Stain

31
Q

Microscopic Exam

This stain causes fungi to turn black with a green background
Used for Pneumocystis Jirovecii using bronchoalveolar lavage

A

Grocott Gomoris Methenamine Silver GMS Stain

32
Q

Microscopic Exam

used for detection of fungal spores and hyphae
Calcofluor White binds to CHITIN in cell wall – fluoresces in UV
Wood Lamp detects dermatophytes

A

Immunofluorescence

33
Q

Culture of Fungi

This has DEXTROSE which promotes fungal growth (pH 5-6)
Inhibits growth of bacteria (Antibiotics – chloramphenicol)
Incubate between 25-37 C

A

Sabouraud Dextrose Agar SDA

34
Q

This test is used for specific antibodies, to screen for disease, establish specifi diganoses and montior disease
Performed with puriofied or recombinant Ags to detect disease-specific anitbodies

Postive indirect test for Antibodies and Antigens

A

AGGLUTINATION

35
Q

Aggulination Method

Ags attached to a carrier (RBC or beads) –> add sample –> if Ig is present in the sample what will happen?

A

Ag-coated RBC or beads will clump

36
Q

Fungal Pathogen

Characterstics of this fungi:
Yeast Cells bud with a unique”lip” – colarette
Liphophilic fungi – growth stimulated by oil

A

Malassezia Furfur

37
Q

transmission of this fungi

is through direct/indirect transfer of keratinous material from person-to-person
Prevalence in the tropics

A

Malassezia Furfur

38
Q

PITYRIASIS

this fungi presents as small, hypopigmented/hyperpigmented spots on chest, back, arms, shoulders

A

Malassezia Furfur

39
Q

Microscopy

spaghetti and meatball appearance = mix of hyphae and yeast

A

Malassezia Furfur

40
Q

Characterstics

Dematiaceous = soil fungi dark in color due to melanin expression
branched septate hyphae
Melanin = antiphagocytic virulence factor

A

Hortaea Weneckii

41
Q

Presentation – Tinea Nigra

solitary, irregular pigmented macules on palms and soles
Biopsy to r/o melanoma

A

Hortaea Weneckii

42
Q

Trichophyton, Epidermophyton and Microsporum are reffered as?
Produce keratinases to utilize keratin as a nutrient

A

Dermatophytes

43
Q

Presentation – RINGWORM – Tineas

classic pattern = ring of inflammatory scaling with diminution of inflammation toward center of lesion
if nails are infected they will thicken, discolor, raise and be deformed

Jock Itch – groin, feet – athletes foot

A

Trichophyton, Epidermophyton and Microsporum

44
Q

Characterstics – dimorphic fungi

Mold = daisy petal conidia in soil
Yeast = cigar shaped blastoconidia in humans
outbreaks from gardencing – rose growers disease

A

Sporothrix Schenckii

45
Q

Presentation – sporothrichosis

painless nodular lesions (cellulitis) along lymphatics draining from inoculation site
May ulcerate with pus formation

Entry = spores introduced into skin but damage (thorn)

A

Sporothrix Schenckii

46
Q

Virulence Factor – Sporothrix Schenckii

blocks the action of ROS to evade phagosome-mediated damage in phagocytes

A

Ergosterol Peroxide

47
Q

Characterstics

Gray to wooly colony growth on SDA cycloheximide

A

Mucorales

48
Q

Presentation – zygromucosis – rhinocerebral

meningitis also involving facial structures, nasal sinuses and orbits
necrotic eschars on nasal cavity, hard palate, or face

A

Mucorales

49
Q

Presentation – zygromucosis – pulmonary

focal pulmonary lesions with necrosis – fungus ball
fever, labored breathing, cough

A

Mucorales

50
Q

Presentation – zygromucosis – cutaneous

cellulitis that progresses to dermal necrosis and black eschar formation
associated with IV drug use

A

Mucorales

51
Q

Virulence Factor – Mucorales

proliferate in the walls of blood vessels and cause tissue infarcation

A

Invasive Hyphae

52
Q

Characterstics

Dematiaceous
Muriform Bodies founds in animals and humans = brown septated cells with vertical/horizontal lines in same planes

A

Chromoblastomycosis

53
Q

Presentation – fonsecaea pedrosoi

Chronic, pruritic, progressive warty papules
Develop - cauliflower like lesions clustering in the same region

A

Chromoblastomycosis

Microbio (4 decks)

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