This invention is an apparatus and method for susceptibility testing one or more biofilms, for selecting one or more anti-microbial combinations with efficacy against the biofilm, and/or in treating a disease or condition mediated by the biofilm. The invention includes methods for the selection of antibiotic combinations with efficacy against a specific microbial type and for the formulation of microbe-specific test plates. The invention also includes an assay system to test patient specific isolates for sensitivity to the anti-microbial combinations.