Student Author(s)

Sean Slayton, Hope College

Faculty Mentor(s)

Dr. Vicki Isola, Biology

Document Type


Event Date



Multi-drug resistant (MDR) bacteria are strains of bacteria that are resistant to multiple types of antibiotics and pose a serious public health threat. Our research group has developed a novel way to rapidly screen soil bacteria isolates for antimicrobial chemical production in a clear and reproducible manner. We examined the effects of certain variables on our method including: 1) agar type on antimicrobial diffusion, 2) agar depth on antimicrobial diffusion, 3) age of the soil isolate on the amount of antimicrobial produced, and 4) soil isolate placement on the inhibition of bacterial growth. Our combined results led to the creation of a novel "bilayer plate" combining two stacked agar layers of different agar types and the use of a novel "cross inoculation" technique to screen soil isolates for the production of antimicrobial substances. This new method, which we call "The Isola-Slayton Method," was used in the identification of several soil isolates that produced substances which inhibited multiple ESKAPE bacterial species (a set of bacterial pathogens that often cause MDR healthcare-associated infections). This new method may provide a quick and effective way to test microbial isolates in the pursuit of new antibiotics.


This research was supported by the Hope College Biology Department.

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