Page 172 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

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

Dilution and Diffusion

E test, Antimicrobial Gradient method

• Combines the principle of dilution methods with
that of diffusion methods in order to determine
the MIC value.

• E test technique comprises a predefined gradient
of antibiotic concentrations on a plastic strip

• can be used to determine the MIC of antibiotics, antifungal agents and

antimycobacterial agents

• MIC value is determined at the intersection of the strip and the growth
inhibition ellipse

Advantages

• Simple performance

• Flexibility in the testing of any combination of antibiotics

• They do not require expertise and special technologies

• More suitable when only a couple of antibiotics are needed to be tested.

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