Antibiotic Substances: Part II. Antifungal Assays

Publisher Summary This chapter focuses on measuring the growth response of a microorganism to an antifungal antibiotic. There are a variety of techniques for measuring the growth response of a microorganism to an antifungal antibiotic, the most common one involving reading the turbidity caused by the growth of the microorganism in a liquid medium. Turbidimetric assay methods depend upon inhibition or retardation of growth of a test microorganism by the substance to be measured. Simple readings of turbidity made visually in a series of tubes may suffice if the specific situation does not require discrimination of differences in antibiotic concentration of less than twofold. In general, the degree of turbidity can be determined with greater precision and objectivity with a photometer than by eye. To illustrate this form of assay, a serial dilution assay and several photometric methods are described in the chapter.