HSS 1100 MIDTERM 2 EXAM SCRIPT WITH
VERIFIED SOLUTIONS
◉ What are the 6 important gram positive bacteria and how are they
classified? Answer: - 2 cocci (staphylococci and streptococci)
- 4 rods (2 spore formers and 2 non-spore formers
◉ What are the two types of spore forming, gram positive rods?
Answer: Bacillus and Clostridium
◉ How do spore forming gram positive rods cause disease? Answer:
By releasing potent exotoxins
◉ What is the main difference between the 2 spore-forming gram-pos
rods? Answer: Bacillus is aerobic
Clostridium is anaerobic
◉ How many species of Bacillus? Answer: 2
◉ What are the names of the different bacillus species? Answer:
Bacillus anthracis and Bacillus cereus
◉ What is the causative agent of anthrax? Answer: Bacillus anthracis
(gram-positive, spore-forming rod)
◉ What is the causative agent of gastroenteritis? Answer: Bacillus
cereus
,◉ What makes Bacillus anthracis unique? Answer: It is the only
bacteria with capsule made of protein (prevents phagocytosis)
◉ Who does anthrax primarily affect? Answer: herbivores like cows
and sheep
◉ How are humans usually exposed to Bacillus anthracis? Answer:
Exposed to spores during direct contact with infected animals or soil
◉ Characteristics of B. anthracis spores Answer: - very stable
- resistant to drying heat, UV light, and disinfectants
- spores germinate and make toxins
◉ What regulates B. anthracis germination? Answer: - temp increase
to 37 degrees Celsius
- carbon dioxide increases
- serum proteins
◉ Bacillus anthracis spores only activate when ___ Answer:
introduced to a host
◉ What is one use of Bacillus anthracis? Answer: Used for biological
terrorism and warfare (used by Japanese army in Manchuria)
◉ What encodes for the Bacillus anthracis exotoxin? Answer:
Plasmid called pXO1
,◉ What is Bacillus anthracis exotoxins made up of? Answer: 3
separate proteins which are not toxic on their own
1) Edema factor (EF) - disrupts water homeostasis
2) Protective antigen (PA) - promotes EF entry into phagocytic cells
3) Lethal factor (LF) - inactivates protein kinase
◉ What encodes for Bacillus anthracis capsule genes? Answer:
plasmid pXO2
◉ What two things are needed for Bacillus anthracis to be bacterially
virulent? Answer: both plasmid pXO1 and pXO2
◉ Prevention and treatment for Bacillus anthracis Answer: - rapid
identification and treatment to reduce mortality
- treatment includes: penicillin, doxycyclin
- vaccine available for humans
- animals sometimes vaccinated with live cultures that have had their
capsules removed
◉ How is Bacillus cereus different from Bacillus anthracis? Answer: -
motile
- non-encapsulated
- resistant to penicillin
◉ What does Bacillus cereus cause and how? Answer: food poisoning
when spores are present in food (nausea, vomiting, and diarrhea)
which then survive initial cooking process, allowing them to
germinate in the food and release the enterotoxin
, ◉ How can you inactivate Bacillus cereus spores when cooking?
Answer: - expose to high temps
- refrigeration
◉ What are the two types of toxins made by Bacillus cereus Answer:
Heat labile toxin and heat stabile toxin
◉ Heat-labile toxin - Bacillus cereus Answer: - similar cholera and LT
from E.coli
- cause nausea, abdo pain, diarrhea
- lasts 12-24 hrs
◉ Heat stabile toxin - Bacillus cereus Answer: - similar to S. aureus
food poisoning
- short incubation period
- severe nausea and vomiting
- limited diarrhea
◉ Why would antibiotics not help with Bacillus cereus? Answer:
Because the pre-formed toxins are what causes the food poisoning,
the toxins stay for brief time even if bac is dead
◉ Characteristics of Clostridium species Answer: - gram pos, spore
forming
- anaerobic
- anaerobic culture helps differentiate from spore forming rods
- extremely powerful exotoxins
VERIFIED SOLUTIONS
◉ What are the 6 important gram positive bacteria and how are they
classified? Answer: - 2 cocci (staphylococci and streptococci)
- 4 rods (2 spore formers and 2 non-spore formers
◉ What are the two types of spore forming, gram positive rods?
Answer: Bacillus and Clostridium
◉ How do spore forming gram positive rods cause disease? Answer:
By releasing potent exotoxins
◉ What is the main difference between the 2 spore-forming gram-pos
rods? Answer: Bacillus is aerobic
Clostridium is anaerobic
◉ How many species of Bacillus? Answer: 2
◉ What are the names of the different bacillus species? Answer:
Bacillus anthracis and Bacillus cereus
◉ What is the causative agent of anthrax? Answer: Bacillus anthracis
(gram-positive, spore-forming rod)
◉ What is the causative agent of gastroenteritis? Answer: Bacillus
cereus
,◉ What makes Bacillus anthracis unique? Answer: It is the only
bacteria with capsule made of protein (prevents phagocytosis)
◉ Who does anthrax primarily affect? Answer: herbivores like cows
and sheep
◉ How are humans usually exposed to Bacillus anthracis? Answer:
Exposed to spores during direct contact with infected animals or soil
◉ Characteristics of B. anthracis spores Answer: - very stable
- resistant to drying heat, UV light, and disinfectants
- spores germinate and make toxins
◉ What regulates B. anthracis germination? Answer: - temp increase
to 37 degrees Celsius
- carbon dioxide increases
- serum proteins
◉ Bacillus anthracis spores only activate when ___ Answer:
introduced to a host
◉ What is one use of Bacillus anthracis? Answer: Used for biological
terrorism and warfare (used by Japanese army in Manchuria)
◉ What encodes for the Bacillus anthracis exotoxin? Answer:
Plasmid called pXO1
,◉ What is Bacillus anthracis exotoxins made up of? Answer: 3
separate proteins which are not toxic on their own
1) Edema factor (EF) - disrupts water homeostasis
2) Protective antigen (PA) - promotes EF entry into phagocytic cells
3) Lethal factor (LF) - inactivates protein kinase
◉ What encodes for Bacillus anthracis capsule genes? Answer:
plasmid pXO2
◉ What two things are needed for Bacillus anthracis to be bacterially
virulent? Answer: both plasmid pXO1 and pXO2
◉ Prevention and treatment for Bacillus anthracis Answer: - rapid
identification and treatment to reduce mortality
- treatment includes: penicillin, doxycyclin
- vaccine available for humans
- animals sometimes vaccinated with live cultures that have had their
capsules removed
◉ How is Bacillus cereus different from Bacillus anthracis? Answer: -
motile
- non-encapsulated
- resistant to penicillin
◉ What does Bacillus cereus cause and how? Answer: food poisoning
when spores are present in food (nausea, vomiting, and diarrhea)
which then survive initial cooking process, allowing them to
germinate in the food and release the enterotoxin
, ◉ How can you inactivate Bacillus cereus spores when cooking?
Answer: - expose to high temps
- refrigeration
◉ What are the two types of toxins made by Bacillus cereus Answer:
Heat labile toxin and heat stabile toxin
◉ Heat-labile toxin - Bacillus cereus Answer: - similar cholera and LT
from E.coli
- cause nausea, abdo pain, diarrhea
- lasts 12-24 hrs
◉ Heat stabile toxin - Bacillus cereus Answer: - similar to S. aureus
food poisoning
- short incubation period
- severe nausea and vomiting
- limited diarrhea
◉ Why would antibiotics not help with Bacillus cereus? Answer:
Because the pre-formed toxins are what causes the food poisoning,
the toxins stay for brief time even if bac is dead
◉ Characteristics of Clostridium species Answer: - gram pos, spore
forming
- anaerobic
- anaerobic culture helps differentiate from spore forming rods
- extremely powerful exotoxins
