Lecture 9 - Clostridium

Question 1

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

Answer 1

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

Question 2

which of the 4 clostridium species dicussed form spores?

Answer 2

ALL OF THEM DO

Question 3

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

Answer 3

clostridium difficile

Question 4

name the 4 general properties of the clostridium family

Answer 4

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

Question 5

in general, where is the clostridium family present

Answer 5

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

Question 6

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

Answer 6

through toxins (specific for each species)

Question 7

true or false

clostridium bacteria are not part of our endogenous flora

Answer 7

FALSE – they are

Question 8

what is the toxin for clostridium tetani

Answer 8

tetanospasmin

Question 9

what is the toxin for clostridium perfinges

Answer 9

alpha toxin, Iota toxin, and enterotoxin

Question 10

what is the toxin for clostridium botulinum

Answer 10

botulinum

Question 11

what is the toxin for clostridum difficile

Answer 11

A enterotoxin and B cytotoxin

Question 12

which clostridium species causes antibiotic-associated diarrhea?

Answer 12

clostridium difficile

Question 13

which clostridium species causes gangrene?

Answer 13

clostridium perfringens

Question 14

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

Answer 14

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

Question 15

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

Answer 15

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

Question 16

what kind of infections does clostridium perfringes cause?

Answer 16

soft-tissue infections from cellulitis to gangrene

Question 17

explain what gangrene is

Answer 17

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

Question 18

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

Answer 18

food poisoning, endometritis, sepsis, necrotizing enterocolitis

Question 19

what is unique about clostridium tetani

Answer 19

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)

Question 20

name the toxins of clostridium tetani

Answer 20

tetanospasmin (A-B toxin)
tetanolysin

Question 21

explain what tetanospasmin does

Answer 21

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

Question 22

what does tetanolysin do

Answer 22

pore-forming toxin

Question 23

what is the main symptom of a clostridium tetani infection

Answer 23

tetanus

Question 24

what muscles are often the first affected in tetanus?

Answer 24

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

Question 25

where is clostridium botulinum common?

Answer 25

in soil and in water

Question 26

in what conditions do the spores of clostridium botulinim germinate?

Answer 26

in anaerobic conditions

Question 27

which spores of the clostridium family are heat resistant?

Answer 27

botulinum

Question 28

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

Answer 28

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!!!

Question 29

name 4 ways in which you can get botulism

Answer 29

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

Question 30

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

Answer 30

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

Question 31

botulinum toxins blocks ______ release at the _____

Answer 31

blocks acetylcholine release at the neuromuscular junction

Question 32

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

Answer 32

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

Question 33

explain how a clostridium difficile infection develops

Answer 33

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

Question 34

the SPORES of clostridium difficile are common where?

Answer 34

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

Question 35

what are the symptoms of a clostridium difficile infection

Answer 35

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

Question 36

name the toxins of clostridium difficile

Answer 36

enterotoxin (toxin A) Cytotoxin (toxin B)

Question 37

explain what enterotoxin (toxin A) of clostridium difficile does

Answer 37

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

Question 38

explain what cytotoxin (Toxin B) of clostridium difficile does

Answer 38

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

Question 39

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

Answer 39

INCREASED TOXIN PRODUCTION caused by a mutated regulatory gene