Bacterial Pathogenesis 1 Flashcards

1
Q

Transduction vs transformation vs conjugation

A

Transformation: kill and uptake
Transduction: Phage
Conjugation: sex pili

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2
Q

Two naturally competent bacteria

A

Bacillus subtilis and strep pneumo (Nat. competent usually only take up linear DNA, not circular or from phages)

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3
Q

Bacteria that only transform their own genus

A

H. Influenza and Neissera Gonorrhoeae

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4
Q

A transducing phage transfers DNA during the…

A

lytic phase

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5
Q

What two organelles assist in gene transfer in conjugation?

A

Relaxasomes and Transferasomes

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6
Q

F plasmids

A

contain “tra” genes for transfer. Result in sex pili

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7
Q

Col plasmids

A

contain bacteriocins (proteins to kill bac) or genotoxins (kill host cells)

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8
Q

mob plasmids

A

can only transfer by hitchhiking along with other plasmids that contain tra genes

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9
Q

Pathogenicity islands

A

10-200kb and have different G+C% content than rest of the bac chromosome

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10
Q

EPEC and EHEC

A

Enteropathogenic and enterohaemorrhagic E. Coli. Attach to actin pedestals and inject molecules into the host cells

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11
Q

Facultative intracellular bacteria

A

have genes that control virulence factor expression so they can survive both inside and outside of host cells

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12
Q

Enzymes that destroy cell defences, made by extracellular bacteria

A

chemokines, sIgA

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13
Q

How intracellular pathogens are different

A
  • resistant to Reactive OS and NO, (superoxide dismutase, SOD, made by Staphylococci and salmonella) (Listeria suppresses NO synthase expression in host)
  • Legionella and Mycobacterium prevent phagolysosome fnx
  • Listeria, Francisella, and Rickettsia escapre phagosomes
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14
Q

Listeria

A

Gram+ facultative anaerobe. 3rd leading cause of death due to food poisoning. Uses genes like plcA and hly. These lead to InIA and InIB make non-phagocyte cells to phagocytose bacteria (muahahaha!) by changing actin cytoskeleton

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15
Q

What nutrients are in high demand in the body?

A
  1. Metals/cations (Fe, Mn, Zn, Cu, Mo)
  2. Amino Acids
  3. Carbs
  4. O2 and other election acceptors
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16
Q

Three ways that bacteria avoid dying from lack of amino acids inside a cell

A
  1. M. Tuberculosis makes its own tryptophan
  2. C. Trachomatis turns reticulate bodies into aberrant bodies
  3. L. pneumophila uses ankB and polyUb to use host as a food source
17
Q

Enterobactin

A

a molecule made by bacteria to steal iron from host. Host counters with lipocalin which breaks down enterobactin. Bacteria counters by glucosylating enterobactin.

18
Q

Salmonella

A

Cause typhoid (enteric fever, humans only) and gastroenteritis (non-typhoid, affect many animals)

19
Q

Salmonella PA1-encoded effectors

A

trigger host membrane ruffles that envelope and internalize bound bacteria

20
Q

Toxin types

A

I- bind and act as host cell surface (super antigens)
II- Act on host cell membrane (phospholipase and pore-forming toxins)
III- A-B type toxins, includes single chain (DT and BoNT) and multisubunit toxins (cholera and anthrax toxins)

21
Q

Other ways to categorize toxins

A
  • non-protein vs protein
  • Endotoxin vs exotoxins
  • effector proteins
22
Q

Non-protein toxins

A

aka Endotoxins. Stimulate TLR4 or TLR2/6. Lead to septic shock, DIC or Acute respiratory system

23
Q

Mycobacterium ulcers makes a ____ toxin called _____ that does _____

A

non-protein, polyketide-derived mycolactone, Buruli ulcers (necrotic lesions)

24
Q

Superantigens bind ____ outside the peptide cleft

A

MHC II. T cells are activated and then exhausted and die, inflammation goes crazy. Spread by diarrhea

25
Staph Aureus
- 1/3 of population is colonized - thrives in hospital (HA-MRSA) - Daycare and wrestlers (CA-MRSA) - Causes food poisoning, sepsis, abscesses, and cellulitis, bacteremia/sepsis - Surfaces have adhesins, capsule, Protein A, MSCRAMMS
26
Protein A
binds IgG
27
Toxic Shock Syndrom toxin 1
TSST-1, superantigen (superabsorbent tampons that grew staph aureus)
28
AgrC and AgrA
Sensor Kinase and Response Regulator (Hamemelitannin from witch hazel inhibits MRSA quorum sensing)
29
E. Coli can sense
Adrenergens in the body
30
Phospholipases
-a toxin of C. perferingens: hydrolyzes the lipid lecithin, contributes to gangrene
31
Pore-formin toxins
- Alpha (helixes) - Beta (barrel) - These represent about 30% of the toxins - Eg Aerolysins (inserts itself spirally)
32
A/B toxins
A subunit is responsible for the enzymatic activity, B mediates binding
33
How do A/B toxins enter cells?
- Fuse with endosomes (DT, BoNT) | - Retrograde transport (cholera and shiga toxin)
34
Cholera Toxin does what?
produces abnormally high cAMP levels, cause more Cl- to be produced in gut. Diarrhea, dehydration, loss of electrolytes.
35
What is Diptheria?
Colonization of throat by Corynebacterium diphtheriae. G+, non-motile, aerobic. Only in humans. Causes a pseudomembrane in throat and lungs; removal can make you bleed, can make you choke.
36
How does DT enter cells?
Heparin-binding epidermal growth factor (HB-EGF)-like receptors. These are present in the heart and nerve cells in large numbers
37
Toxoids
non-toxic version of a toxin, used in a vaccine. Can affect children and adults