Diagnostics And Infectious Diseases Flashcards by Mireya Smith

M cell function

Endocytosis of Ag and presentation of Ag
Aka microfold cells

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Shigella pathogenesis

Invaginates in M cells and stops degradation of the bacteria —> invades and kills enterocytes —> gets into lymphatics

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Cilia or flagella core filament composition

Microtubule

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Microvilli filament composition

Actin

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Which organisms take advantage of cilia?

Mycoplasma and CAR (filobacterium)

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Exotoxins vs endotoxins

•Exotoxins: proteins produced inside bacteria and secreted, gram+ bacteria
•Endotoxins: elements of the bacterial membrane and are liberated when bacteria die (e.g., LPS), gram— bacteria

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What does an epsilon toxin do and what pathogen can produce this?

An exotoxins that induces BBB permeability via caveolae-dependent transcytosis

Clostridial perfringens type B or D

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What pathogens can encode enterotoxins?

E. coli, rotavirus (nsp4), salmonella, C. difficile, Cryptosporidia

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What do pore-forming toxins (PFTs) do?

Disruption of barriers, cell entry, killing inflammatory cells

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Antigenic drift vs antigenic shift

•Drift: point mutation, usually doesn’t alter AA composition
•Shift: large change in viral genome

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How does antigenic shift occur?

•Reassortment: segmented RNA viruses - 2 or more different viral strains infect same cell and reassemble to form new, mixed virus
•Recombination: DNA and RNA viruses - nucleic acid strand break then rejoined to end of different DNA molecule

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Rotavirus
-virus type
-significant proteins/other factors

•Nonenveloped dsRNA virus
•Viral capsid attachment proteins: VP4 & 7
•Produces enteritoxin NSP4 - secretory diarrhea, hypermotility, inc intracellular Ca, cell membrane dysfunction

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Rinderpest, CDV, measles
-virus type
-significant proteins/other factors

•Morbillivirus, enveloped RNA virus
•CD150/SLAM receptors on host cell
•Proteins hemagglutinin (H) for attachment and fusion (F) for syncytial cell production

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Classical swine fever, BVD
-virus type
-significant proteins/other factors

•Enveloped RNA virus
•Replication in tonsillar crypts
•Attachment proteins: Erns and E2

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African swine fever
-virus type
-significant proteins/other factors

•Enveloped DNA virus
•Glycoproteins p12, p54, p30

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Parvovirus
-virus type
-significant proteins/other factors

•Nonenveloped DNA virus
•Peyer’s patches, continuously dividing cells

Rabies
-virus type
-significant proteins/other factors

•Lyssavirus, enveloped RNA virus
•Binds G envelope protein to cell receptors
•Entera via clathrin-coated pigs
•Retrograde axonal transport

Immune response to fungal infections

Th17 cells

Cryptococcus neoformans virulence factors

•Polysaccharide capsule:
-glucuronoxylomannan: inhibits phagocytosis
-galactoxylomannan
-blocks dendritic cell maturation
•Glucosylceramide synthase
•Phospholipase
•Urease
•Melanin production

Blasto virulence factors

•BAD1 - adherence to CR3 and CD14 receptors on alveolar macs
•Melanin and glucans
•Change surface polysaccharides and hides and phagosomes

Histoplasmosis virulence inflammation type

Requires T cells - Th1
-induces macs to secrete TNF

Histoplasma virulence factors

•Inhibition of phagolysosome acidification, lysosomal proteases
•Leukocyte trafficking

Coccidioidomycosis life stages

Arthroconidia (soil [inhaled]) > spherules > endospores inside spherules > release of endospores > mycelia > arthroconidia formation

Coccidioidomycosis virulence factors

•Spherule outer wall glycoprotein
•Host tissue arginase I and coccidioidal urease

Aspergillus virulence factors

•Adhesins •Antioxidants - melanin, mannitol, catalases, superoxide dismutases •Phospholipases, proteases •Alfatoxin

BSE uptake in body and tissue sample for diagnosis

Follicular dendritic cells Obex/DMNV

Listeria monocytogenes -mode of transport -virulence factors -cell of infection

-Retrograde axonal transport > internalins using E-cadherins > escape via listeriolysin O, phospholipase C, lecithinase -Surface protein actA - polymerization of target cell actin filaments -Infects endothelial cells > perivascular microabscesses

Brucellosis -mode of entry -virulence factors

-M cells, transcytosis -phagosome-lysosome fusion blocked via rapid acidification -leukocyte trafficking

Secretion system bacteria examples 1-6

1. Apoptosis; Salmonella, Actinobacillus 2. Actinobacillus 3. Invasion, cytotoxic; Salmonella, Actinobacillus, ETEC, Yersinia 4. Brucellosis 5. 6.

Salmonellosis -mode of entry -survival tactic

-M cells, enterocytes - via endocytosis -inhibit phag-lysosome fusion

Bacillus anthracis -virulence factors

-capsule -protective antigen - facilitates toxin entry -lethal factor (lethal toxin) and edema factor

Clostridium perfringens -cytotoxins functions

-alpha and beta: enterocytes membrane and ECM toxins -epsilon: inc enterocytes/endothelial cell permeability > change IV absorption of toxins -iota: disrupts cytoskeleton > cell lysis

Clostridium perfringens A and B domains functions

A (light chain): cleave proteins within target cells that form synaptic fusion complex (SFC/SNARE proteins) B (heavy): mediate transport via endo/exocytosis

Cl. tetani vs. botulinum

Tetanus: prevents RELEASE OF GABA > spastic paralysis Botulism: prevents RELEASE OF ACh > flaccid paralysis

ETEC vs EHEC vs EPEC -virulence factors

•ETEC: K99 or F41 fimbrial adhesins; secrete heat labile (LT) and heat stable (ST) enterotoxins •EHEC: shiga toxins, verotoxin •EPEC: espA/espB/espD, verotoxin

Which bacteria form biofilms?

Pseudomonas, streptococci, legionella

•Virulence factor transmission •Bacterial transfer of genes

•Horizontally •Vertical to offspring and horizontal between bacteria

Horizontal gene transfer methods: Conjugation vs transformation vs transduction

•Conjugation: direct transfer of plasmids b/w bacteria •Transformation: take up pieces of bacteria from environment from dead bacteria (“competent”) •Transduction: transfer by bacteriophages b/w closely related bacteria