Abstract: The effect of a chemical on bacterial growth is rapidly determined by culturing a sample of bacteria in the presence of said chemical for a period of time sufficient to obtain detectable bacterial growth. During the culturing period, a labelled nucleotide is added to the growth media and the uptake of said nucleotide is measured and compared to a control.

Abstract: Method, apparatus and automated system for determining the effects of a chemical agent upon a bacterial sample. Aliquots of a bacterial suspension in a culture medium, the chemical agent, and tritiated thymidine are deposited in polyethylene tubes having first and second compartments separated by a fixed millipore filter. A precipitation agent, such as trichloroacetic acid, is deposited into the polyethylene tubes to precipitate the bacteria. The bacteria is separated from the liquid by operation of a vacuum system which draws the liquid through the filter, thereby filtering out the bacteria. The filtered bacteria is subsequently washed with a washing solution. In one embodiment, a scintillation fluid is added to the bacteria, the bacteria then being conveyed to a scintillation counter which produces an output signal corresponding to the amount of radiation emanating from the bacteria.