Therapeutic activity of teicoplanin on experimental listeriosis compared with that of vancomycin and ampicillin.

Several strains of Listeria monocytogenes and other Listeria spp. are without exception susceptible to teicoplanin (MIC 0.25 mg/l). Vancomycin as well as ampicillin are likewise active. A bactericidal effect of teicoplanin was only achieved at rather high concentrations and after incubation of several hours. There is no synergistic effect between teicoplanin and gentamicin. The therapeutic activity of teicoplanin as well as vancomycin in mice infected with L. monocytogenes is low. The efficacy of ampicillin could not be achieved. Treatment of chronically infected athymic, nude mice with teicoplanin is ineffective. Consequently, teicoplanin is not able to replace ampicillin in the therapy of listeriosis.