A compound of the formula ##STR1## wherein R.sup.1 is amino or substituted amino, R.sup.2 is carboxy or protected carboxy, R.sup.3 is lower alkyl and X is --S-- or ##STR2## or a pharmaceutically acceptable salt thereof is effective against various microorganisms.
式为##STR1##的化合物,其中R.sup.1为
氨基或取代
氨基,R.sup.2为羧基或保护羧基,R.sup.3为低碳基,X为--S--或##STR2##或其药学上可接受的盐,对各种微
生物有效。