This in vitro study was aimed to compare the intrinsic activity of modern 3
(rd) generation fluoroquinolones (enrofloxacin, difloxacin, marbofloxacin,
and orbifloxacin) in current isolates of companion and livestock animals. O
ur results prove the good in vitro performance of the whole class, but clea
rly underline the great superiority of enrofloxacin regarding MICs, MBCs an
d the killing in all bacterial species investigated. In times of a constant
ly growing awareness of a rational use of antimicrobials, this investigatio
n was restricted to bacterial species claimed by the marketing authorisatio
n of fluoroquinolones. The activities were determined quantitatively (MIC,
MBC, time-kill-studies). Those data allow-in contrast to qualitative data (
susceptible, intermediate and resistant)-a state of the art judgement of di
fferent antimicrobials.