The invention relates to novel compounds of high antimicrobial activity of the formula: <IMAGE> wherein R1 is amino or acylamino; and R9 is a group of the formula: <IMAGE> wherein R2 is organic group, X is CH or N, Z is acid residue Y is CH or N and n is O; or Y is N(+)-R2 wherein R2 is as defined above and n is 1, or a group of the formula: -A-N(+)(R10)3 wherein R10 is lower alkyl and A is lower alkylene.
