Alatrofloxacin

7-[(1R,5S,6R)-6-[(2S)-2-[(2S)-2-aminopropanamido]propanamido]-3-azabicyclo[3.1.0]hexan-3-yl]-1-(2,4-difluorophenyl)-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid; methanesulfonic acid