Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microorganisms, Infection and Immunity > Bacterial Pathogenesis > Flashcards

Bacterial Pathogenesis Flashcards

1
Q

Every human is colonised,.

A

by numerous bacterium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

A pathogen is

A

an organism that cause infection in individuals with normal host defences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A commensal is…

A

an organism that is found normally on those parts of the body that they are exposed to, or communicate with, the external environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

An opportunist is where

A

an organism that can cause infection in individuals with abnormal host defences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Koch’s postulates states….

A
  1. pathogen must be present in every case of disease
  2. Pathogen must be isolated from the diseased hose and grown in pure culture
  3. the specific disease must be reproduced when a pure culture of the pathogen is inoculated into a healthy host
  4. pathogen must be recoverable from the experimentally affected host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Disease can arise in several different ways…

A
  1. some bacteria are entirely adpated to the pathogenic way of life in humans. They are never part of the normal flora but may cause subclinical infection.
  2. Some bacteria which are part of the normal flora acquire extra virulence factors making them pathogenic
    3.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Changes in normal flora

A
  1. changes in normal physiology and development
  2. when antibiotics select for a resistant flora
  3. new organisms may be acquired.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pathogens can transmit via

A

oral-oral, fecal-oral, blood and sexual contact, Animals, vectors, environment and food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Microbial pathogenicity factors are…

A

examples of PAMP’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

bacteria need

A

cell wall associated proteins in order to bind to host cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Gram positive proteins

A

have surface proteins which allow the attachment of the bacteria to the cell of the host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Gram negative bacteria use pili and fimbriae to

A

bind to host cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Bacterial flagellae

A

confer motility to many bacteria and it is another example of a PAMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Bacteria also needs to get something to eat

A

This occurs via the invasion of host cells. This is an example of a DAMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Toxins produce different bacteria

A
  1. Exotoxins, which is any toxin that is actively secreted by a bacterium in the environment
  2. endotoxin (such as Lipopolysaccharides in gram negative bacteria)
  3. enterotoxin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Exotoxins can act like

A

proteases, .and other degrading enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Type III secretion system

A

are needed for the delivery of toxins

18
Q

for a bacteria to protect itself, it could…

A

make a polysaccharide capsule, slime, and biolfilm. LPS can be modulated by bacteria to cause cytokine overstimulation and lead to septic shock. Outer membrane proteins could affect antimicrobial peptides and complement factors

19
Q

Bacterial adaptation is

A

adapting to changing and new environments

20
Q

Microbe- host interactions include

A
  1. preventing opsonization
  2. toxin secretion can paralyze the host’s defences
  3. Disruption of mucosal integrity
  4. microbial recognition and host responses
  5. chemokine production
  6. inspired by modification of PAMP or interference with intracellular signalling or cell trafficking.
21
Q

Regulatory networks include

A

Two component systems such as LPS modification, Quorum sensing, and Efflux pumps (drug resistance)

22
Q

SIGNAL -

A

Environmental change - signalling molecule

23
Q

Regulator

A

usually specific DNA binding protein - binds in control region

24
Q

Regulon

A

Group of genes controlled by a common regulator

25
Q

Bacterial Regulons include

A
  • catabolite suppression
  • DNA supercoiling
  • SOS response to DNA damage
26
Q

2CS

A

Stimulus response mechanism - signal transduction….

27
Q

When there is a low magnesium concentration in a macrophage

A

salmonella can hijack the low MG conditions which can modulate transcription and expression of genes

28
Q

When a plant detects low calcium,

A

an immune response can be regulated to protect itself against a microbe

29
Q

A biofilm is a…

A

structured community of bacterial cells enclosed in a self produced polymeric matrix and adherent to an inert or living surface. Biofilm formation is considered to be a pathogenic trait.

30
Q

Quorum sensing is

A

key to biofilm formation. This mechanism of biofilm formation is cell density dependent. Low molecule weight compounds autoinducers.

31
Q

QS signal molecules include

A

PQS, HHQ, HHQNQ

32
Q

Efflux pumps are

A

-encoded by all bacteria, regardless of antibiotic load or environment
- regulated by chromosomal factors
One example of such pumps are the RND pumps.

33
Q

The regulation of efflux pumps can be

A

local repressors, global regulators (2 Component systems, AHL signalling systems)

34
Q

AcrR acts as a

A

local repressor of the efflux pump

35
Q

Secretion systems facilitate

A

intra and intercellular communications- Necessary for export of nutrients and protection
against host-mediated response

36
Q

The type of secretion system depend on

A

cell wall structure
- Gram positive - transportation of protein through a single membrane
– Gram negative-involves multi-subunit structures-inject
toxin directly into host.

37
Q

Sec & TAT (general secretory pathway)

A 
• Used to transport proteins across
cytoplasmic membrane.
• Highly conserved
• Proteins transported remain within the cell
i.e. periplasm or IM.
• Gram-Neg can transport proteins using secretion systems.
• Common elements but translocation of
proteins is different.
38
Q

Gram positive need a facilitator protein for its secretory pathway called

A

SecA2

39
Q

The SecA2 Secretion pathway…

A

Sec secretion pathway
– Conserved mechanism of protein export
– Used by Staphylococcus and Streptococcus species
to function as adhesins

40
Q

Sortases

A

– Covalently attached proteins on cell wall, survival
during infection
– Embedded in Gram-positive cell wall
– SrtA recognises N-terminal signal peptide
– Eg. Pili

41
Q

The difference between sec and tat is

A

sec transports unfolded proteins and tat transports folded proteins

Microorganisms, Infection and Immunity (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions