MODULE 4: ANTIBIOTIC SENSITIVITY TESTING

Question 1

Also known as the Disk Diffusion Method, widely used antibiotic susceptibility test in determining what treatment of antibiotics should be used to treat an infection.

Answer 1

Kirby-Bauer test

Question 2

Uniformly and aseptically inoculated with the test organism and then filter paper discs, which are impregnated with a specific concentration of a particular antibiotic, is placed on the medium. (Hint: agar)

Answer 2

Mueller-Hinton Agar

Question 3

Antimicrobial agents produced by microorganisms that kill or inhibit other microorganisms.

Any chemical of natural origin (from any type of cell) which has the effect to kill or inhibit the growth of other type’s cells.

Are low molecular weight non protein molecules produced as secondary metabolites, mainly by microorganisms that lives in soil

Answer 3

Antibiotics

Question 4

Are the most notable antibiotic producers amongst the molds; Main source of beta-lactam antibiotics (penicillin and its relatives)

Answer 4

Penicillium & Cephalosporium

Question 5

Give some examples of antibiotics from bacteria.

Answer 5

• Actinomycetes & Streptomyces spp.
• Aminoglycosides (Streptomycin)
• Macrolides (Erythromycin)
• Tetracyclines
• Endospore-forming Bacillus spp. (Polypeptide antibiotics such as Polymyxin & Bacitracin)

Question 6

For antimicrobial susceptibility testing, the agar medium should have a pH between ____ and ____ at room temp.

Answer 6

7.2 - 7.4

Question 7

Susceptibility tests are normally incubated at _____ for optimal growth.

Answer 7

35 C

Question 8

Most techniques (susceptibility test) adopt an incubation period of between ___ and ___ hours.

Answer 8

16 and 18

Question 9

Susceptibility tests are usually carried out with ____ cm plates and no more than ____ or ____ antibiotic discs on each plate.

Answer 9

9-10; 6 or 7

Question 10

The broth culture is incubated at 35 C until it achieves or exceeds the turbidity of the _______.

Answer 10

0.5 McFarland standard