Abstract
The author describes the in vitro data for antibiotic susceptibility of Rickettsia and Coxiella burnetii. Tetracyclines are still the first antibiotic choice in spotted fevers, typhus and Q fever. In spotted fever a shortened treatment is suggested and the place of macrolide antibiotics, such as Josamycin, in treating children may be evaluated. In Q fever, according to the new biological data, an association of tetracyclines and Rifampin or Quinolones is suggested.