[Activity of antibiotics in body fluids (author's transl)]

MIC and kinetic of bactericidal activity was determined for various antibiotics in body fluids (plasmawater, bile, amniotic fluid and urine). Beta-lactam antibiotics demonstrated slight loss of activity against enterobacteriaceae. The newer cephalosporine compounds, cefoxitin, cefuroxime and HR 756 showed an increase in activity in plasmawater. Carbenicillin was more active in plasmawater, bile and amniotic fluid than in broth. There was a difference in gentamycin activity against enterobacteriaceae and pseudomonas aeruginosa: enhanced activity against E. coli in body fluids and diminished against pseudomonas. Tetracycline was less active in body fluids, specially in alkaline bile. The combination ampicillin/gentamycin against E. coli was more effective in plasmawater than in DST agar. Cefazolin/gentamycin demonstrated no synergism. Although carbenicillin/tobramycin were not synergistic against pseudomonas aeruginosa in plasmawater. The marked differences in different body fluids should be taken into consideration when new antibiotics are introduced.