Lesson 1

Question 1

What are commensals

Answer 1

acquired soon after birth, are able to adhere to body
surface

Question 2

can exist as a commensal in the rumen but when it
transfers to the liver of feedlot cattle it can act as a pathogen that causes hepatic
abscesses.

Answer 2

Fusobacterium necrophorum

Question 3

What is pathogen?

Answer 3

Compete with normal flora to foothold in the niche, bring disease to the host

Question 4

Capacity of the pathogen to produce a disease

Answer 4

Pathogenicity

Question 5

virulence

Answer 5

The degree of pathogen to produce a disease.

Question 6

Virulence factors

Answer 6

Adhesins
Capsule
Toxin

Question 7

Genes encode virulence factors

Answer 7

Plasmid
Bacteriophages
Pathogenicity Island

Question 8

Animals become infected of their own bacteria (microrlora) /..when the
bacteria gain access to sites from which they are usually absent.

Answer 8

Endogenous infection

Question 9

What is exogenous infection?

Answer 9

direct or indirect transmission of pathogen from an
infected animal or from the environment

Question 10

main portals of entry of infection

Answer 10

Mucosae of the
gastrointestinal Respiratory tract
Urogenital tract

Question 11

Pathogen- host interaction

Answer 11

determined by the virulence of the bacteria and by the effectiveness of the host
response.

Question 12

Two categories of pathogen that are able to survive in a host.

Answer 12

Obligate intracellular pathogen
Facultative intracellular pathogen

Question 13

Example of obligate intracellular pathogen

Answer 13

Chlamydiae
Rickettsiae

Question 14

Example of facultative intracellular pathogen.

Answer 14

Mycobacterium sp.
Brucella sp.
Salmonella sp.

Question 15

Major virulence factor

Answer 15

Adhesins
Capsule
Toxins

Question 16

Use by pathogen to attach to host tissues and to resist the flushing action of body fluids

Answer 16

Adhesins

Question 17

Use by uropathogenic E. coli to attach the
epithelial cells of the urinary bladder.

Answer 17

type 1 fimbriae

Question 18

Use by uropayhogenic E. Coli to attach to epithelial cells in the kidney.

Answer 18

P fimbriae

Question 19

a transcription factor
that moves to the cell nucleus where it up-regulates the expression of a number of
pro-inflammatory genes.

Answer 19

nuclear factor-kappaB (NF-κB)

Question 20

Function of capsule

Answer 20

Protecting the bacterium from engulfment of phagocytes, and from attack by antimicrobial agents

Question 21

Components of capsule of bacillus anthracis

Answer 21

Polyglutamic acid

Question 22

Two types of toxin

Answer 22

Endotoxins,
Exotoxins

Question 23

Two types of toxin

Answer 23

Endotoxins,
Exotoxins

Question 24

Two types of toxin

Answer 24

Endotoxins,
Exotoxins

Question 25

lipopolysaccharide (LPS) of the outer leaflet of the outer
membrane of Gram-negative bacteria.

Answer 25

Endotoxins

Question 26

Components of endotoxins

Answer 26

Glycolipid
Polysaccharide (core oligosaccharides)
Opolysaccharide (o antigen)

Question 27

Processes toxic enzymatic activity

Answer 27

A subunit

Question 28

Responsible for binding the exotoxin to specific receptor on the host cell membrane

Answer 28

B subunits

Question 29

Categories of exotoxins:

Answer 29

(i) toxins that act on the extracellular matrix

(ii)
toxins that act on the plasma membrane of their target cells, where they interfere
with transmembrane signalling pathways or alter membrane permeability

(iii) toxins
that act inside the cells, where they modify signalling pathways or the activities of the
cytoskeleton; and

(iv) toxins that cause dysfunction of the immune system, so-called
superantigens.

Question 30

Capable of detecting conserve molecular pattern that are unique to microorganisms and are not expressed by the host

Answer 30

Pattern recognition receptor (PRR)

Question 31

Serves as ligand for host pattern recognition molecules such as toll like receptors.

Answer 31

Pathogen Associated Molecular Pattern (PAMP)

Question 32

If the pathogen is shed into faeces continuously ( asymptomatic)

Answer 32

Latent Carrier

Question 33

If the pathogen is shed into faeces intermettently ( symptomatic)

Answer 33

Active carrier

Question 34

Two routes by which invasive pathogens can reach the epithelial barrier:

Answer 34

Intercellular spaces (paracellular route)
Epithelial cell (transcellular route)

Question 35

Bacteria that can take paracellular routes

Answer 35

enteropathogenic E. coli
Listeria monocytogenes
Helicobacter pylori
Clostridium species
Salmonella serovars.

Shigella sp.

Question 36

Two major type of induced uptake:

Answer 36

Zipper mechanism
Trigger mechanism

Question 37

is induced by specific ligand–receptor
interactions at the cell membrane

Answer 37

zipper mechanism

Question 38

induced by
effector molecules delivered into the cell by a type III secretory system.

Answer 38

trigger mechanism

Question 39

usually have a short severe
clinical course, often a matter of days, and the invading bacteria are usually cleared
from the body by the host’s immune response

Answer 39

Acute infections

Question 40

tend to occur when the host fails to eliminate the
pathogen.

Answer 40

Chronic infections