Cephem compound

The present invention is concerned with a novel cephem compound, with a process for the production of this compound, which process may contain or consist of fermentative steps, chemical steps, and/or biotransformation steps. A cephem compound according to the present invention characterised by formula (I) or a salt or ester thereof, wherein R is selected from the group consisting of (carboxymethylthio)propionyl (carboxyethylthio)propionyl Y-CH2-CO15 wherein Y is phenyl, phenoxy or tetrazolyl HOOC-X-CO wherein X is defined as (CH2)4 or wherein X is defined as (CH2)P-A-(CH2)q, wherein p and q each individually are 0, 1, 2, 3 or 4, and A is CH-CH, C--C, CHB, C-O, O, S, NH, the nitrogen optionally being substituted or the sulfur optionally being oxidized, and B is hydrogen, halogen, C1-3 alkoxy, hydroxyl, or optionally substituted methyl, with the proviso that p+q should be 2 or 3, when A is CH-CH or C--C, or p+q should be 3 or 4, when A is CHB, C-O, 0, S or NH or wherein X is (CH2)m-CH=A-(CH2)n or (CH2)m-C--C-(CH2)n, wherein m and n each individually are 0, 1, 2 or 3 and m+n=2 or 3, and A is CH or N, or wherein X is (CH2)p-CH-CH-C H-C-(CH2)q wherein p and q each individually are 0 or 1 and p+q=0 or 1 and wherein R' is selected from the group consisting of OH O-(alkyl 1-6C) wherein the alkyl can be straight or branched and O-C(alkyl 1-6C)-O-(alkyl 1-6C) wherein the alkyl groups can be straight or branched can inter alia be prepared by fermentative techniques according to the invention and in particular using a suitable microorganism possessing or being transformed with the genes needed for conversion of an appropriate acyl-6-aminopenicillanic acid into the desired compound.