EVALUATION OF THE SERUM BACTERICIDAL TEST

The serum bactericidal test (SBT) is used to monitor antibiotic treatment during therapy. Compared to other methods of sensitivity testing, such as MIC (minimum inhibitory concentration) determination, the SBT also takes into consideration the pharmacokinetic qualities of the drug tested. Serum bactericidal titers are measured during therapy of different infectious diseases to estimate therapeutic outcome. Until now serum bactericidal titers of 1:8 in non-granulocytopenic patients, and titers greater-than-or-equal-to 1:16 in granulocytopenic patients have been shown to correlate with a successful treatment outcome in patients with gram-negative sepsis. In patients with endocarditis a peak serum bactericidal titer of at least 1:32 should be achieved Another way to apply the serum bactericidal test is to compare the activity of different antibiotics in volunteers. The present study as well as data from the literature indicate that ciprofloxacin has markedly higher serum bactericidal activity than ofloxacin. Of the so called ''basic cephalosporins'' cefotiam achieved the highest serum bactericidal activity against the Enterobacteriaceae tested Since 3rd generation cephalosporins are in general highly active against gram-negative rods, we were interested in using the SBT to compare different dosage regimens. In several studies serum bactericidal titers of greater-than-or-equal-to 1:8 were achieved with the 1 g dosis of cefotaxime, cefmenoxime and especially ceftazidime against the gram-negative rods tested.