ins ▁and ▁U . S . s . ▁However , ▁this ▁can ▁vary ▁depending ▁on ▁the ▁species ▁of ▁b acter ia . ▁In ▁general , ▁combinations ▁of ▁a ▁b acter i ost atic ▁ant ib i otic ▁and ▁b acter ic idal ▁ant ib i otic ▁are ▁ant agon istic . ▁ ▁Class es ▁ ▁Ant ib iot ics ▁are ▁commonly ▁class ified ▁based ▁on ▁their ▁mechanism ▁of ▁action , ▁chemical ▁structure , ▁or ▁spectrum ▁of ▁activity . ▁Most ▁target ▁b acter ial ▁functions ▁or ▁growth ▁processes . ▁Those ▁that ▁target ▁the ▁b acter ial ▁cell ▁wall ▁( pen ic ill ins ▁and ▁ce phal os por ins ) ▁or ▁the ▁cell ▁memb rane ▁( pol ym y x ins ), ▁or ▁inter f ere ▁with ▁essential ▁b acter ial ▁en zym es ▁( rif am yc ins , ▁li pi ar my c ins , ▁qu in ol ones , ▁and ▁sul fon am ides ) ▁have ▁b acter ic idal ▁activities . ▁Prote in ▁synth esis ▁in hib itors ▁( mac rol ides , ▁l inc os am ides , ▁and ▁t et racy cl ines ) ▁are ▁usually ▁b acter i ost atic ▁( with ▁the ▁exception ▁of ▁b acter ic idal ▁am in og ly cos ides ). ▁Further ▁categor ization ▁is ▁based ▁on ▁their ▁target ▁specific ity . ▁" N arrow - spect rum " ▁ant ib iot ics ▁target ▁specific ▁types ▁of ▁b acter ia , ▁such ▁as ▁gram - negative ▁or ▁gram - pos itive ,