In vitro activity of trovafloxacin, of other fluoroquinolones and of related antimicrobials against clinical isolates.

The in vitro activity of trovafloxacin (TRV) has been evaluated in comparis on with that of other antimicrobial agents against 5671 clinical isolates r ecovered by representative institutions of different provinces in our count ry. The resistance percentage to gentamicin and third generation cephalospo rins among enterobacteriaceae was high: 17% and 16% respectively, with a co nsiderable variation according to the analyzed species. The resistance to c iprofloxacin (CIP) and TRV affected approximately 9% of the isolates, witho ut significant differences between both drugs. Fluoroquinolones (FQ) presen ted excellent activity on 166 isolates of Salmonella spp., 208 of Shigella flexneri and 76 of Shigella sonnei, where only one S.sonnei isolate was res istant to CIP, but susceptible to TRV. About half the isolates of Salmonell a spp. and S.sonnei and almost all S.flexneri isolates were resistant to am picillin, and more than 60% of Shigella spp. isolates were resistant to tri methoprim-sulfamethoxazole. a 41% of Staphylococcus aureus and 55% of coagu lase-negative staphylococci isolates were resistant to oxacillin, presentin g a highly associated multi-resistance. The resistance to FQ was also stron gly related to oxacillin resistance, but the resistance to TRV was signific antly lower than the CIP resistance: 9% vs 57% for S.aureus and 4% vs 41% f or coagulase-negative staphylococci. A similar behavior was observed with E nterococcus spp., where 54% of the isolates were resistant to norfloxacin a nd only 13% were resistant to TRV. Neither Streptococcus pneumoniae (n=193) nor Haemophilus influenzae (n=139) isolates presented resistant to TRV.