| Abstract
| - The effect of trovafloxacin on Staphylococcus aureus ingested by humangranulocytes or monocytes was compared with that on S. aureus in cell-free medium.Maximum growth inhibition (ER,max) by the antibiotic was 0.530 log10/h for S. aureus within granulocytes, 0.912 log10/h for S.aureus within monocytes, and 1.830-1.916 log10/h for S. aureusin medium. EC50, the concentration at which 50% of the maximum growthinhibition is achieved, did not differ significantly under the conditions investigated. Afterinhibition of intracellular killing by granulocytes with sodium fluoride, the intracellularantibacterial activity of trovafloxacin was still less than that in medium. A 3.4 times higherconcentration was needed to achieve the same effect on phagocytosed S. aureus as incell-free medium. Trovafloxacin binds more strongly to granulocytes than to monocytes, therespective cellular concentrations being 10 and four times higher than that in medium. Inconclusion, the activity of trovafloxacin against S. aureus ingested by humangranulocytes or monocytes is less than that against S. aureus in cell-free medium and isnot related to the cell-associated concentration. Intracellular conditions are not favourable for theantibacterial activity of trovafloxacin.
|
