The invention provides novel antibiotic compounds which are 7.beta.-acylamidoceph-3-em-4-carboxylic acids, and non-toxic derivatives thereof, and 6.beta.-acylamidopenam-3-carboxylic acids, and non-toxic derivatives thereof, characterized in that the acylamido group has the structure ##STR1## where R is a hydrogen atom or an organic group and R.sup.a is a hydrogen atom or an acyl group. The compounds are syn isomers or exist as mixtures containing at least 75% of the syn isomer. These antibiotic compounds possess high antibacterial activity against a range of gram positive and gram negative organisms coupled with particularly high stability to .beta.-lactamases produced by various gram negative organisms. The invention is also concerned with the administration of the compounds.
本发明提供了新型抗生素化合物,它们是7.beta.-acylamidoceph-3-em-4-carboxylic acids及其非毒性衍
生物,以及6.beta.-acylamidopenam-3-carboxylic acids及其非毒性衍
生物,其特征在于酰胺基团具有结构##STR1##其中R为氢原子或有机基团,R.sup.a为氢原子或酰基。这些化合物是同构体或存在至少75%的同构体混合物。这些抗生素化合物具有高抗菌活性,对一系列革兰氏阳性和革兰氏阴性微
生物具有高度稳定性,特别是对各种革兰氏阴性微
生物产生的 .beta.-内酰胺酶具有高度稳定性。本发明还涉及这些化合物的使用。