[Comparative efficacy of ampicillin, chloramphenicol, cefotaxime, ceftriaxone and pefloxacin in experimental Salmonella typhimurium infection].

The efficacies of various antibiotics were compared in Salmonella typhimurium infection in mice. Treatment began 24 h after challenge. Antibiotics were given subcutaneously every 12 or 24 h in the following daily doses: 200 mg/kg for ampicillin, 100 mg/kg for chloramphenicol, cefotaxime and ceftriaxone, 50 mg/kg for pefloxacin. The number of bacteria in the spleens was determined after 3 and 7 days of treatment. In animals treated with ceftriaxone or pefloxacin the mean number of bacteria per spleen was from one to two log10 lower than in animals treated with other antibiotics. Similar results were obtained in genetically susceptible or resistant mice. The MIC being similar for cefotaxime, ceftriaxone and pefloxacin, the better in vivo activity of the two latter drugs appears to be related to their pharmacokinetic properties.