Zone of Inhibition Test - Kirby-Bauer Test

Welcome to Antimicrobial Test Laboratories' Zone of Inhibition Test Resource Page. The assay pictured here is also sometimes called a Kirby-Bauer Test and is used regularly by clinical laboratories under CLSI guidelines to determine antbiotic resistance of bacterial isolates.

Photograph: A zone of Inhibition is evident around the oxacillin disk for S. aureus, left, but not for Methicillin-resistant S. aureus (MRSA), right.

Below, you will find a summary of the Kirby-Bauer Zone of Inhibition test method, along with some of its strengths and weaknesses. The Kirby-Bauer Zone of Inhibition test method is designed to qualitatively test the ability of antimicrobial agents to inhibit the growth of microorganisms over an 18-24 hour period of contact.

Summary of the Zone of Inhibition Test:

Strengths of Zone of Inhibition Testing:

Weaknesses of Zone of Inhibition Testing:

Zone of Inhibition Testing is a fast, qualitative means to measure the ability of an antimicrobial agent to inhibit the growth of microorganisms.

Antimicrobial Test Laboratories was built around antimicrobial innovation and antimicrobial research and development. If your company is interested in screening chemicals, products, or antimicrobial treatments for their ability to inhibit the growth of microorganisms, the zone of inhibition test may be a great place to start.

For more information about Zone of Inhibition testing, Contact the Lab Today!