Brainscape's Knowledge GenomeTM

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


See full index

Microbes > L16 - Bacterial Pathogenicity > Flashcards

L16 - Bacterial Pathogenicity Flashcards

1
Q

Pathogenicity / virulence

A

the capacity to cause disease

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

Commensals

A

normal microbial flora - healthy host (never cause disease)

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

Mutalists

A

both host and microbes gain an advantage (gut microbia)

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

opportunistic pathogens

A

do not normally cause disease - normally commensal

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

what are the four types of bacteria ?

A

commensals, mutalists, opportunistic pathogens, highly virulent pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pseudomonas aeruginosa Gram

A

plants and soil - infects severe burns patients - colonizes lungs of cystic fibrosis patients - muco ciliary escalator in lung is compromised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

S. epidermidis

A

infects catheters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does S. epidermidis infect catheters?

A
  1. s. epidermidis cells attach to catheter
  2. blood plasma proteins coat the catheter (forming a conditioning film)
  3. S. epidermidis multiplies on the plasma proteins and forms a community (biofilm) on the catheter and this is antibiotic resistant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does s. epidermidis grow as on the catheter?

A

a biofilm

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

Neisseria meningitidis causes what?

A

opportunistic infections

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

How is Neisseria meningitidis transmitted?

A

through respiratory droplets by close or pronlonged contact

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

What is the average incubation period of Neisseria meningitidis

A

4 days

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

What does it mean when something is a systemic infection?

A

It is not confined to one part of your body

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

Myocobacterium tuberculosis (TB) is an example of what kind of pathogen?

A

highly virulent pathogen

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

What does the body form as a way to rectify TB?

A

Ghon complexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the stages of TB?

A
  1. primary lesion - chancre at site of infection in 2 wks
  2. secondary stage (after 10 wks) - bacteria spreads to eyes, joints, bones and skin
  3. latent phase (years) - 40% develop tertiary syphilis - insanity and death
17
Q

What is Kochs postulates?

A

Koch’s postulates were formulated in the late nineteenth century as guidelines for establishing that microbes cause specific diseases.

18
Q

What did Dr Barry Marshall do?

A

Swallowed a culture and developed gastritis - proved for helicobacter pylori

19
Q

What are the problems encountered in carrying out Koch’s postulates?

A
  1. cannot grow cultures on laboratory media - only human hosts for certain things
  2. ethical problems make the tests impossible - AIDS, Ebola, etc..
  3. no suitable animal model
20
Q

What is virulence?

A

degree of pathogenicity

21
Q

How do you measure virulence?

A

Minimum infectious dose
by LD50 (lethal dose) : dose to kill 50% of animals (or cells) in a given time

22
Q

LD50 is also used for what?

A

To quantify relative toxicity of toxins

23
Q

What are the two virulence factors that determine virulence?

A
  1. capsule - of poly-D-glutamid acid (inhibits phagocytosis) - mucoid colonies when capsulate
  2. toxins - supresses immune cell responses early in infection later in infection lethal levels induce toxic shock and death (not all bacteria has this)
24
Q

What happens if capsule OR toxins are lost in strains?

A

they become attenuated

25
Q

What do bacterial capsules do?

A

they protect the cells ffrom phagocytosis by the host

26
Q

What is the first stage in the bacterial disease process?

A
  1. bacteria enter the hose and adhere by specific mechanisms
27
Q

All commensals living on the epithelia ______ to the host

A

adhere

28
Q

How does adhesion work in commensals

A

composed of protein subunits - carrying a tip adhesin (protein H)
specifically attaching the mannose receptors on the surface of epithelial cells

29
Q

How does adhesion work for pathogens

A

they adhere selectively to epithelial surfaces
fimbriae carry adhesions

30
Q

Pathogenic E.coli use wht to attach to the duodenal mucosa?

A

CFA fimbriae (colonization factor antigen)

31
Q

how else can pathogens adhere to the host?

A

non-fimbrial adhesins - strep sore throat, impetigo

32
Q

How does adhesion without fimbriae work?

A

streptococcus pyogenes M protein (non-fimbrial adhesin) covers the bacterial surface and mediates attachment to an epithelial cell

Microbes (11 decks)

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