[A microbiological method for the rapid determination of antibiotic concentrations during therapy (author's transl)]

The assay described is an agar diffusion test using Bacillus stearothermophilus as test organism. Incubation is at 62 degrees C; results can be obtained rapidly within 2 to 3 hours. The test was developed for the determination of gentamicin concentrations in serum and other body fluids. Because of its high sensitivity the test strain is also suitable for the determination of other antibiotics. The test is designed primarily for the determination of concentrations in individual samples and thus for monitoring during therapy. The ease with which the test can be carried out is thus an important feature of it. On comparison with a standard method (agar diffusion test) using both serum samples from patients and samples with known gentamicin concentrations a highly significant correlation (r = 0.95) was seen between the two methods.