Section 4: gram positive endospore forming bacilli

Question 1

What are the characteristics of the clostridium species?

Answer 1

anaerobic metabolism
G+
endospore forming rod
found in soil and water
endospores resistant to heat and chemicals
produce variety of enzymes and toxins

Question 2

What is the pathogenesis of Clostridium perfringens?

Answer 2

food poisoning: type A=abdominal cramps and diarrhea begin 8-22 hours and persist for 1-2 weeks, type C=necrotic enteritis (pig-bel) causes massive necrosis and bleeding often fatal

Question 3

What is the pathogenesis of clostridium botulinum?

Answer 3

food poisoning
seven types of neurotoxins that block release of ACh from presynaptic terminals
results in flaccid paralysis
adult botulism
infant botulism
wound botulism

Question 4

What is adult botulism?

Answer 4

endospores float in air and land on food, not cooked and placed in anaerobic environment will exporulate and produce neurotoxin
causes double vision, nausea, vomitting within 18-36hours, muscle weakness, sudden resp. paralysis and death

Question 5

What is infant botulism?

Answer 5

when infants eat C. botulinum infected food
linked to consumption of honey
causes muscle weakness (floppy baby) but most recover

Question 6

What is wound botulism?

Answer 6

endospores from air land in wound
nuerotoxin causes nause, double vision, and vomiting within 18-36 hours, leads to muscle weakness, sudden respiratory paralysis, and death

Question 7

What are the characteristics of clostridium tetani?

Answer 7

endospores have drumstick shape, found in soil and animal feces

Question 8

What is the pathogenesis of clostridium tetani?

Answer 8

endospores deposited in wound, grow as long as necrotic tissue (anaerobic environment) is present, releases exotoxin called tetanospasmin
blocks inhibitory impulses to muscles and causes sustained contraction

Question 9

What is lockjaw?

Answer 9

jaw spasms, risus sardonicus

from clostridium tetani

Question 10

What is opisthotonos?

Answer 10

spasm in back muscles, head is thrown backward and the back is bowed like an arch
from clostridium tetani

Question 11

What is clostridium difficile?

Answer 11

part of normal intestinal flora in a minority of population

the difficult clostridium because it was resistant to early attempts to isolate and grow in culture

Question 12

What is the pathogenesis of clostridium difficile?

Answer 12

pseudomembranous colitis: severe infection of colon, most resistant to antibiotics
produces: Toxin A=enterotoxin binds to brush border membranes of the gut, and Toxin B=cytotoxin damages gut cells
characterized by offensive smelling diarrhea, fever, abdominal pain, can be fatal

Question 13

What are the characteristics of Bacillus species?

Answer 13

aerobic metabolism
G+ rod
endospore forming-looks like bamboo

Question 14

What is unique about bacillus anthracis?

Answer 14

only bacterium with capsule composed of protein

prevents phagocytosis

Question 15

Cutaneous anthrax

Answer 15

contact with infected animal

endospores enter via cut/abrasion-exotoxin creates painless black lesion usually resolves spontaneously

Question 16

gastrointestinal anthrax

Answer 16

ingestion of spores in contaminated meat
releases exotoxin and causes necrotic lesion in intestine, mouth or pharynx
vomiting, abdominal pain, diarrhea
bacteria enter blood=fatal

Question 17

inhalational antrhax

Answer 17

endospores small fit into alveoli
increase temp to 37C cause exporulation
exotoxins create hemorrhage, edema, necrosis
pleural effusions
nonspecific symptoms
high mortality rate

Question 18

What are the characteristics of bacillus cereus?

Answer 18

G+rod
motile
endospores
non-encapsulated
resistant to penicillin
aerobic metabolism

Question 19

What is the pathogenesis of Bacillus cereus?

Answer 19

food poisoning, two different toxins to cause diarrheal and emetic versions