Microbiology - chapter 6 - Bacillus and Clostridium

Question 0

Name the two species of pathogenic spore-forming, gram positive aerobic rods?

Answer 0

Bacillus anthracis - causing anthrax

Bacillus Cereus - causing gastroenteritis

Question 1

Pair em’ up correctly:

Bacillus - Aerobic
Clostridium - Anaerobic

Answer 1

They are paired up correctly ;)

Question 2

Bacillus anthracis is the only bacterium with ………. ?

Answer 2

capsule composed of protein(poly-D-glutamic acid)

Question 3

What regulates the virulence fators pXO1 and pXO2 plasmids in bacillus anthracis?

Answer 3

• increase in temperature to 37 degrees
• carbondioxide concentration
• serum proteins

Question 4

What is the most common route of entry for bacillus anthracis?

Answer 4

skin = cutaneous anthrax infection.

Question 5

Where, in pulmonary anthrax, do the spores germinate?

Answer 5

They are transported from the lungs to the hilar lymphnodes by macrophages, where they germinate.

Question 6

What toxins are the bacillus anthracis plasmid pXO1 coding for?

Answer 6

1 Edema factor(EF) - increases cAMP levels, impair neutrophils, cause edema.
2 Protective antigen(PA) - promotes EF entry into cells.
3 Lethal factor(LF) - zinc metalloproteinase that inactivates protein kinase.

Question 7

What is the bacillus anthracis plasmid pXO2 coding for?

Answer 7

It encodes three genes necessary for the synthesis of a poly-glutamyl capsule.

Question 8

motile, non-encapsulated penicillin resistant bacillus?

Answer 8

Bacillus cereus

Question 9

Bacillus cereus codes for two enterotoxins that cause two types of food poisoning, what are they?

Answer 9

1 A heat-labile toxin: causes nausea, abdominal pain and diarrhea

2 A heat-stable toxin: severe nausea and vomiting, limited diarrhea

Question 10

Anaerobic organism responsible for causing botulism, tetanus, gas gangrene and pseudomembranous colitis?

Answer 10

Clostridius.

Question 11

Clostridium botulinum, pathomechanism?

Answer 11

Potent neurotoxin that blocks ACh release from presynaptic nerveterminals in autonomic nervous system and motor endplates.

Question 12

Tetanospasmin, pathomechanism?

Answer 12

toxin produced by clostridium tetani. Tetanospasmin acts on the inhibitory Renshaw cell interneurons preventing the release of GABA and glycine, which are inhibitory nurotransmitters. This inhibition of inhibitory neurons causes tetanus

Question 13

risus sardonicus?

Answer 13

grotesque grinning expression due to tetanous cotraction of the facial muscles

Question 14

Three main groups of patients with skin wounds that exhibit tetanus?

Answer 14

Patients that:

1 had their last shot of vaccine more than ten years ago.
2 never have been immunized.
3 already have developed tetanus

Question 15

What organism causes gas gangrene?

Answer 15

Clostridium perfingens

Question 16

What are the three cases of clostridium perfingens incetions that are seen the clinics?

Answer 16

1 Cellulitus/wound infection.
2 Clostridial myonecrosis - inoculated into muscle with trauma, the bug secretes exotoxins to destroy surrounding tissues
3 diarrhel illness - in foods such as pultry, meats and gravy

Question 17

Pseudomembranous enterocolitis is commonly caused by this bug?

Answer 17

Clostridium difficile

Question 18

antibiotika associated pseudomembranous enterocolitis is often a result of this bug?

Answer 18

clostridium difficile

Question 19

What toxin are secreted by Clostridium difficile?

Answer 19

Toxin A - causing diarrhea

Toxin B - cytotoxic to colonic cells

Question 20

How does vancomyosin relate to antibiotika-associated pseudomembranous enterocolitis?

Answer 20

Vancomyosin is unique in that it is not absorbed when taken orally, and therefore remain in the GI tract at the site of action.