The invention provides novel antibiotic compounds which are 7.beta.-acylamidoceph-3-em-4-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 an etherifying monovalent organic group linked to the oxygen atom through a carbon atom. 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,其为7.beta.-acylamidoceph-3-em-4-carboxylic酸及其非毒性衍
生物,其特征在于酰胺基具有结构##STR1##其中R是氢原子或有机基团,R.sup.a是通过碳原子连接到氧原子的醚化一价有机基团。这些化合物是syn异构体或存在至少含有75%syn异构体的混合物。这些抗生素化合物具有高抗菌活性,可针对一系列革兰氏阳性和革兰氏阴性微
生物,并具有特别高的稳定性,能够抵抗各种革兰氏阴性微
生物产生的β-内酰胺酶。本发明还涉及这些化合物的使用方法。