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223 MYCOLOGOUS > Lesson 1 And 2 > Flashcards

Lesson 1 And 2 Flashcards

1
Q

The ability of a microbe to damage a host is
called ?

A

Pathogenicity

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2
Q

The bacterial traits that confer pathogenicity are called ?

A

Virulence factors include Adhesions , capsule and toxins.

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3
Q

the relative capacity of a pathogen to damage a host is the
?

A

Degree of virulence

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4
Q

genes are
expressed only when their products are required in a process called?

A

Phase variation

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5
Q

Mobile genetic elements are ?

A

Bacteriophage
Plasmids
Pathogenicity islands

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6
Q

It 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.
?

A

Fusobacterium necrophorum

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7
Q

They are Able to adhere to body
surfaces.

A

Commensal organisms,

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8
Q

The composition of the microbial communities?

A

host-specific and,
within hosts, to be organ- specific

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9
Q

primes
the immune system, facilitating a more efficient host response to challenge by
bacterial pathogens

A

Normal microflora

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10
Q

The
microflora of the rumen synthesizes what ?

A

vitamin K and some of the vitamin B

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11
Q

This arise when bacteria that live on the skin or mucous
membranes as harmless commensals take advantage of impaired antimicrobial
defenses of the host and behave as opportunistic pathogens?

A

Endogenous infections

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12
Q

This occur after direct or indirect transmission from an
infected animal or from the environment.

A

Exogenous infections

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13
Q

Pathogens may enter a host through ?

A

the skin,
the conjunctiva,
the
umbilicus, or
the teat canal

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14
Q

The main portals of entry are ?

A

the mucosae of the
gastrointestinal,
respiratory and
urogenital tracts

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15
Q

In bacterial infections, the host may be damaged by?

A

By bacterial toxins,
by the
inflammatory response elicited by the bacteria or their toxins or, commonly, by both
toxins and inflammatory reactions

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16
Q

This may also be a
source of tissue damage?

A

The immune responses of the host

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17
Q

Pathogens that
are able to survive within host cells are grouped into two categories ;

A
  1. strict (obligate)
    intracellular pathogens $ 2. facultative intracellular pathogens
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18
Q

These are are obligate intracellular pathogens

A

Chlamydiae and
rickettsiae

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19
Q

It enter and replicate in phagocytic cells

A

Mycobacterium species

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20
Q

It invade and replicate in non-phagocytic epithelial cells

A

Brucella species,
Uropathogenic E. coli,
Salmonella species
Listeria monocytogenes

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21
Q

Pathogens use ________ to attach to host tissues and to resist the flushing
action of body fluids

A

Adhesins

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22
Q

It is subject to phase variation in response to
local conditions.

A

The expression of adhesins

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23
Q

It attach to the
epithelial cells of the urinary bladder

A

Type 1 fimbriae of uropathogenic E. coli

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24
Q

It attach to
epithelial cells in the kidney

A

P fimbriae

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25
Q

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

A

factor-kappaB (NF-κB)

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26
Q

The binding of complement and antibody to the bacterial surface,
thus protecting the bacterium from engulfment by phagocytes and from attack by antimicrobial agents

A

Capsules interfere
with opsonization,

27
Q

Is resistant to phagocytic cells because of its
large size.

A

Biofilm

28
Q

Is composed of polyglutamic acid; it is anti-phagocytic and is regarded as an essential
virulence factor.

A

The capsule of Bacillus anthracis

29
Q

Bacterial toxins have been considered to be of two types:

A
  1. exotoxins
  2. endotoxins
30
Q

Produced and secreted by viable bacteria

A

Exotoxins

31
Q

Are integral
constituents of the bacterial cell wall not released until the microorganisms are lysed

A

Endotoxins

32
Q

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

A

Endotoxin

33
Q

It is composed of three parts

A
  1. hydrophobic
    glycolipid (lipid A)
  2. hydrophilic polysaccharide composed of a core
  3. oligosaccharide and an Opolysaccharide (O antigen)
34
Q

It resides in the lipid A
portion.

A

Toxicity

35
Q

It is released when bacterial cell walls are damaged by the
complement system, phagocytes or antimicrobial drugs

A

Lipopolysaccharide

36
Q

The in vivo effects of
endotoxin depend on ?

A

The amount present in the circulation.

37
Q

High concentrations of
circulating endotoxin greatly increase the release of ?

A

Cytokines

38
Q

It induce fever, activate
macrophages and clotting factor XII, and stimulate B cells to divide and produce
antibodies.

A

Released cytokines

39
Q

It stimulate the production of prostaglandins and leukotrienes
which are mediators of inflammation

A

Cytokines

40
Q

It is responsible for the deposition of thrombi in small vessels (disseminated intravascular
coagulation) and for a dramatic drop in blood pressure, giving rise to life-threatening
endotoxic shock.

A

LPS

41
Q

Exotoxins can be produced by either ?

A

Gram-positive or Gram-negative bacteria

42
Q

They are highly antigenic proteins that can induce the production of protective
antitoxins

A

The toxins

43
Q

It is ingested in contaminated food and produces systemic effects.

A

Clostridium botulinum toxin,

44
Q

possesses toxic enzymatic activity

A

A
subunit

45
Q

Is responsible
for binding the exotoxin to specific receptors on the host cell membrane and may
help in the transfer of the B subunit across the cell membrane.

A

B subunit

46
Q

Both tetanus toxin and botulinum toxin have what ?

A

A–B subunit structure.

47
Q

Categories of exotoxins

A

(i) toxins that act on the extracellular matrix;
(ii)
toxins that act on the plasma membrane of their target cells,
(iii) toxins
that act inside the cells, where they modify signalling pathways or the activities of the
cytoskeleton;
(iv) toxins that cause dysfunction of the immune system, so-called
superantigens.

48
Q

Are capable of detecting conserved molecular ‘patterns’ that are unique to microorganisms and are not expressed by the
hosts?

A

pattern-recognition receptors (PRRs)

49
Q

These microbial ‘patterns’ are present in commensals and pathogens
, they are known as ?

A

pathogen-associated molecular patterns (PAMPs)

50
Q

Mammals possess a family of transmembrane PRRs, called ?

A

toll-like
receptors (TLRs)

51
Q

Can detect the molecular signatures of microbial pathogens, they orchestrate the
innate immune responses, and they help to initiate the adaptive immune response

A

TRLs

52
Q

If an enteric pathogen sequestered in the gall
bladder or in lymph nodes and is not excreted in the faeces, the host is described as

A

latent carrier

53
Q

If the pathogen is shed in faeces, either continuously or
intermittently, the host is considered as?

A

active carrier

54
Q

It secretes
a number of toxins that degrade the epithelial barrier and allow the opportunistic
pathogen to enter the subepithelial tissues.

A

Pseudomonas aeruginosa

55
Q

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

A

by passage through the intercellular spaces (the paracellular route), or

by
passage through the epithelial cells (the transcellular route).

56
Q

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

A

The zipper mechanism

57
Q

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

A

trigger mechanism

58
Q

It is invariably peracute and fatal

A

Anthrax in ruminants

59
Q

Bacterial infections can be conveniently categorized as

A

acute,
subacute,
chronic or
persistent

60
Q

It has usually have a short severe
clinical course, often a matter of days

A

Acute infections

61
Q

Produce clinical effects of less
intensity

A

Subacute infections

62
Q

It tends to occur when the host fails to eliminate the
pathogen

A

Chronic infections

63
Q

It occurs in certain sites such as the uriniferous tubules and the CNS in
which the effects of cell-mediated and humoral immunity are minimal. Persistent
shedding may occur from some of these sites as in bovine leptospirosis, in which
leptospires may be shed in urine for more than a year.

A

Persistence

223 MYCOLOGOUS (1 decks)

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