In vitro activity of sagamicin against ocular bacterial isolates

The in vitro antibacterial activity of sagamicin, gentamicin, tobramycin and norfloxacin was evaluated against 180 recent clinical isolates obtained from patients with ocular infections. Good activity was demonstrated for the 3 aminoglycosides against methicillin-sensitive Staphylococcus aureus and Staphylococcus epidermidis. All 4 compounds showed a lower activity against methicillin-resistant staphylococci. Sagamicin was highly effective against enterobacteriaceae with a MIC(90) of 2 mg/l and presented good antipseudomonal activity similar to that of gentamicin. Intraocular lenses impregnated with a sagamicin solution showed a good antistaphylococcal activity immediately after preparation. In our strain collection, the ability to produce slime was more frequent among methicillin-resistant S. epidermidis strains than methicillin-sensitive S. epidermidis (85 versus 70%). The attachment of 2 S. epidermidis strains to plastic surfaces was partially prevented by sagamicin subinhibitory concentrations. On the contrary, sub-MIC levels of norfloxacin increased the adhesion of S. epidermidis.