Bacteria OBJ B7

Question 1

Major component of a typical bacterial cell wall… etc etc…

Answer 1

slide 7 table

Question 2

What is the component of LPS that is endotoxin, what triggers its release, and its effect on the body

Answer 2

Lipid A
Lyses of Gram negative rod
(systemic inflammation, fever, fatal shock)

Question 3

Differentiate exotoxins and endotoxins in therms of how they normally escape their source.

Answer 3

Endotoxin is lysed to release the toxin

Exotoxin, the toxin is released during replication

Question 4

What produces exotoxin?

Answer 4

Gram positive or gram negative replicating bacteria

Question 5

What produces endotoxin?

Answer 5

gram negative

Question 6

What is the class enterotoxins belong to?

Answer 6

exotoxins

Question 7

What are the three mechanisms by which enterotoxins cause diarrhea?

Answer 7

inhibit NaCl resorption, activate NaCl secretion, or kill intestinal epithelial cells

Question 8

Interpret presence or absence of lactose fermentation on MacConkeys agar, and identify the number one lactose fermenter.

Answer 8

Purple if presence of lactose fermentation

Number one lactose fermenter is E. Coli!

Question 9

Explain the term ‘Beta hemolysis’ and identify the prototypical beta hemolytic pathogen.

Answer 9

Beta: complete RBC lysis
clear zone of hemolysis around bacterial colonies
Key example: Str. pyogenes/ Group A strep/ Strep Throat

Question 10

If given a gram-positive cocci, catalase, and coagulase, determine if an unknown bacteria is a staphylococci or streptococci; and if it is staphylococci, determine if it is S. Aureus.

Answer 10

If it grows on Mannitol salt…. or if it bubbles when in contact with peroxide its a positive coagulase and it is staphlococci…
If it coagulates or clumps up it is S. aureus!
(if negative it is s. epidermidis or s. saprophyticus)