Antimicrobiotic Sensetivity Testing (Exercise 31)

Question 1

What antibiotics where suitable for S. aureus?

Answer 1

TE-30, NB-30, C-30, P-10, N-30

Question 2

Which antibiotics wwere suitable for E. coli?

Answer 2

C-30, S-10, TE-30, K-30

Question 3

Which antibiotics were suitable for P. mirabilis?

Question 4

Which antibiotics were suitable for P. aeruginoisa?

Answer 4

S-10

Question 5

Anitbiotic

Answer 5

Kill or inhibit microbes, antibiotics are antimicrobials that are produced by microbes. Ex. Penecillan

Question 6

Broad-spectrum Antibiotics

Answer 6

Effective against many different microbes

Question 7

Narrow-spectrum Antibiotics

Answer 7

Effective only against a few microbes (i.e. gram positive or gram negative)

Question 8

What factors influence the size of the zone of inhibition for an antibiotic?

Answer 8

Diffusion through the agar, resistance, and concentration.

Question 9

Why are certian gram-negative bacteria more resistant than gram-positive bacteria to antibiotics that attack cytoplasmic targets?

Answer 9

Gram negative bacteria have the added protection of an outer membrane making them more resistant to these antibiotics.

Question 10

Why are gram-positive bacteria typically more resistant than gram-negative bacteria to antibiotics that disrupt plasma membranes, such as polymixon B?

Answer 10

Gram-positive bacteria have a thick cell wall making the membrane less permeable.

Question 11

If a bacterial isolate shows intermediate to moderate resistance to an antibiotic, how might this antibiotic still be used in the treatment of this microbe?

Answer 11

Dosage can be increased to be more effective, or a combination could be used.

Question 12

What specific medium must be used in testing the effectiveness of antibiotics?

Answer 12

Mueller Hinton Agar