Compounds having the formula ##STR1## and pharmaceutically acceptable salts thereof which possess antibacterial activity. R.sub.s is a substituted hydroxy pyridone of the formulae: ##STR2## wherein Y.sub.1 is CH.sub.2 X; COOR.sub.6 ; CONR.sub.7 R.sub.8 ; OH; OCH.sub.2 R.sub.9 ; CHF.sub.2 ; CHO; CH.dbd.N--OR.sub.10 ; CH.dbd.CH--R.sub.11 ; CN; CH.dbd.N--NHR.sub.12, and Y.sub.2 is hydrogen; COOH; CONH.sub.2 ; CN; CSNH.sub.2 ; COO lower alkyl; CONR.sub.7 /R.sub.8.
具有以下式##STR1##及其药学上可接受的盐的化合物具有抗菌活性。R.sub.s是以下式的取代
羟基吡啶:##STR2##其中Y.sub.1是CH.sub.2 X;COOR.sub.6;CONR.sub.7 R.sub.8;OH;OCH.sub.2 R.sub.9;CHF.sub.2;CHO;CH.dbd.N--OR.sub.10;CH.dbd.CH--R.sub.11;CN;CH.dbd.N--NHR.sub.12,Y.sub.2是氢;COOH;CONH.sub.2;CN;CSNH.sub.2;COO较低烷基;CONR.sub.7 /R.sub.8。