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Infectious Disease Final > Lecture 9 - Clostridium > Flashcards

Lecture 9 - Clostridium Flashcards

1
Q

what are the 4 species of clostridium prevalent in human disease?
also name the diseases they cause

A

clostridium perfringens – gas gangrene
clostridium tetani – tetanus
clostridium botulinum – botulism
clostridium difficile – diarrhea, colitis

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2
Q

which of the 4 clostridium species dicussed form spores?

A

ALL OF THEM DO

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3
Q

which of the 4 clostridiums discussed are prevalent in hospital environments and are the cause of some nosocomial infections?

A

clostridium difficile

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4
Q

name the 4 general properties of the clostridium family

A

-can form endospores (thus can survive in harsh environmental conditions)
-ANAEROBIC METABOLISM (strict)
-Inability to reduce sulfate to sulfite
-gram POSITIVE cell wall

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5
Q

in general, where is the clostridium family present

A

ubiquitous (everywhere) in soil, water, sewage, AND endogenous flora

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6
Q

how does the clostridium family induce damage (as a general rule)

A

through toxins (specific for each species)

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7
Q

true or false

clostridium bacteria are not part of our endogenous flora

A

FALSE – they are

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8
Q

what is the toxin for clostridium tetani

A

tetanospasmin

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9
Q

what is the toxin for clostridium perfinges

A

alpha toxin, Iota toxin, and enterotoxin

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10
Q

what is the toxin for clostridium botulinum

A

botulinum

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11
Q

what is the toxin for clostridum difficile

A

A enterotoxin and B cytotoxin

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12
Q

which clostridium species causes antibiotic-associated diarrhea?

A

clostridium difficile

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13
Q

which clostridium species causes gangrene?

A

clostridium perfringens

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14
Q

how many types of clostridium perfringes are there? what does the type depend on which type is the mot prevalent in humans?

A

5 different types, depending on their toxin production
A-E
A is the most prevalent in humans

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15
Q

name the lethal toxins of clostridium perfringes.
state their function and which is the “worst” for the host cell

A

alpha toxin – same function as phospholipase C (break down cell membrane) and also causes hemolysis

Iota toxin – is an A-B toxin. B subunit forms pores and A subunit binds G actin

enterotoxin – hate labile toxin. causes fluid loss and also acts as a superantigen

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16
Q

what kind of infections does clostridium perfringes cause?

A

soft-tissue infections from cellulitis to gangrene

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17
Q

explain what gangrene is

A

occurs when bacteria that are rapidly dividing produce a gas metabolite that leads to edema and necrosis (death of cells of tissue)

18
Q

besides soft tissue infections, what other conditions can clostridium perfringens cause

A

food poisoning, endometritis, sepsis, necrotizing enterocolitis

19
Q

what is unique about clostridium tetani

A

the bacteria itself has extreme oxygen sensitivity – will die in the presence of oxygen, but the spores can persist in an oxygen rich environment (such as in open wounds)

20
Q

name the toxins of clostridium tetani

A

tetanospasmin (A-B toxin)
tetanolysin

21
Q

explain what tetanospasmin does

A

is released when the cell lyses.
invades spinal motor neurons of the CNS and undergoes retrograde transport to the soma (body) of the cell.
it BLOCKS INHIBITORY NEUROTRANSMITTER RELEASE (GABA) and causes continuous excitatory neurotransmission

22
Q

what does tetanolysin do

A

pore-forming toxin

23
Q

what is the main symptom of a clostridium tetani infection

A

tetanus

24
Q

what muscles are often the first affected in tetanus?

A

masseter muscles (lock jaw)
more and more muscles are involved with time — affects swallowing and respiration

25
Q

where is clostridium botulinum common?

A

in soil and in water

26
Q

in what conditions do the spores of clostridium botulinim germinate?

A

in anaerobic conditions

27
Q

which spores of the clostridium family are heat resistant?

A

botulinum

28
Q

there are ______ distinct subunits of the Botulinum toxin.
name and explain 2 of them
what does the botulinum toxin as a whole cause?

A

7 subunits of the botulinum toxin
A subunit — is zinc endopeptidase. inhibits the release of acetylcholine (OPPOSITE OF TETANUS TOXIN)

B subunit – binds sialic acids and glycoproteins on motor neurons

causes paralysis!!!

29
Q

name 4 ways in which you can get botulism

A

foodborne (canned foods)
powdered milk (infants)
through a wound (rare)
inhalation – biological weapon??

30
Q

why is the botulinum toxin so popular in the cosmetic industry?

A

it loosens and relaxes the muscles – they CANNOT be stimulated. leads to no wrinkles

31
Q

botulinum toxins blocks ______ release at the _____

A

blocks acetylcholine release at the neuromuscular junction

32
Q

where does clostridium difficile colonize? how is its virulence kept in check?

A

the large intestine
virulence kept in check by NORMAL FLORA and DIMERIC IGA

33
Q

explain how a clostridium difficile infection develops

A

toxin-producing clostridium difficile proliferates following broad-spectrum antibiotic treatment (no more flora to keep it in check)

34
Q

the SPORES of clostridium difficile are common where?

A

in hospital settings – major source of nosocomial outbreaks.
relapse occurs due to presence of spores

35
Q

what are the symptoms of a clostridium difficile infection

A

can be benign, but also can cause severe diarrheal disease (pseudomembranous colitis)

36
Q

name the toxins of clostridium difficile

A

enterotoxin (toxin A)
Cytotoxin (toxin B)

37
Q

explain what enterotoxin (toxin A) of clostridium difficile does

A

it is a chemoattractant for neutrophils, which in turn stimulates cytokine release, which in turn disrupts tight junctions. – makes it easier to get in

38
Q

explain what cytotoxin (Toxin B) of clostridium difficile does

A

induces actin depolymerization — gives bacteria ability to move cell to cell

39
Q

virulence of clostridium difficile is increased with increased……..
what is this caused by?

A

INCREASED TOXIN PRODUCTION
caused by a mutated regulatory gene

40
Q
A

Infectious Disease Final (13 decks)

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