Correlation of the Initial Bacterial Concentration and Detection Time in Indirect Conductimetric Assay

抄録

The correlation between bacterial concentration and the change in electrical conductivity was investigated for the indirect conductimetric assay which measures the conductivity change of an alkaline solution (NaOH) that absorbs the CO₂ produced by bacterial growth and metabolism. The conductivity of the NaOH solution for a sample containing a higher bacterial concentration changed faster than that for a sample containing a lower concentration, and the logarithmic initial bacterial concentration (C_B0) was related to the time (t_D), at which the conductivity of the absorbent changed, in a linear fashion. We derived theoretically the validity of the linear relationship and estimated the generation time (t_g) from the relationship. The t_g values obtained by the indirect conductimetric assay were almost identical to those obtained by the direct conductimetric assay and the Standard Plate Count method.