however , 3 isolates -- from a boy aged 11 months and a girl aged 1 year with meningitis , and a girl aged 2 years with epiglottitis -- were highly resistant to tetracycline , with a median minimal inhibitory concentration of 50 mug tetracycline hydrochloride per ml ( resistance ratio greater than or equal to 50 ) .
C0039644
tetracycline
C0546879
tetracycline hydrochloride