Page 166 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

Basic sets of drugs for routine susceptibility tests

Set 1 Set 2

Staphylococcus Benzyl penicillin Tetracycline Amikacin
Oxacillin Chloramphenicol Co-trimoxazole
Erythromycin Clindamycin

Intestinal Ampicillin Nalidixic acid Norfloxacin
Chloramphenicol Tetracycline
Co-trimoxazole

Enterobacteriaceae Sulfonamide cephalosporins Norfloxacin
Trimethoprim Nitrofurantoin Chloramphenicol
Urinary
Co-trimoxazole Nalidixic acid Gentamicin
ᵦ lactam and Tetracycline

Blood and tissues Ampicillin Tetracycline
Chloramphenicol Gentamicin
Cotrimoxazole

Pseudomonas Piperacillin Tobramycin Amikacin
aeruginosa Gentamicin

Diffusion methods

Disk-diffusion method

• Agar plates are inoculated with a standardized
inoculum of the test microorganism.

• Then, filter paper discs (about 6 mm in

diameter), containing the test compound at a
desired concentration, are placed on the agar
surface. The Petri dishes are incubated under

suitable conditions.

• Generally, antimicrobial agent diffuses into the agar and inhibits
germination and growth of the test microorganism and then the diameters of

inhibition growth zones are measured

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