A quinolone carboxylic acid derivative having the following formula (1), ##STR1## wherein R.sup.1 is a hydrogen atom, an alkyl group, an aralkyl group, an ester residual group which can be hydrolyzed in living bodies, R.sup.2 is a hydrogen atom or an amino group which may be substituted by one or two lower alkyl groups, X is a hydrogen atom or a halogen atom, Y is CH.sub.2, O, S, SO, SO.sub.2, or N--R.sup.3, wherein R.sup.3 is a hydrogen atom or a lower alkyl group, and Z is an oxygen atom or two hydrogen atoms; or a salt thereof; and an antimicrobial agent comprising the same. The compound exhibits a superior antimicrobial activity, especially against gram positive microorganisms, and is thus useful for the treatments and prevention of various infectious diseases in clinics.
具有以下式子(1)的喹诺
酮羧酸衍
生物,其中R.sup.1是氢原子,烷基,芳基烷基,可以在活体中
水解的酯残基,R.sup.2是氢原子或一个或两个较低的烷基取代的
氨基,X是氢原子或卤素原子,Y是CH.sub.2,O,S,SO,SO.sub.2或N-R.sup.3,其中R.sup.3是氢原子或较低的烷基,Z是氧原子或两个氢原子;或其盐;以及包含它的抗微
生物剂。该化合物表现出优异的抗微
生物活性,特别是对革兰氏阳性微
生物,因此在临床上用于各种传染病的治疗和预防。