7-(4-{4-[5-(S)-(Acetylamino-methyl)-2-oxo-oxazolidin-3-yl]-2-fluoro-phenyl}-piperazin-1-yl)-6,8-dilfuoro-1-(2-fluoro-ethyl)-4-oxo-1,4-dihydro-quinoline-f3-carboxylic acid ethyl ester AIDS-167309 AIDS167309