Implantable medical product with permanently negatively charged surface

A medical product, which is either entirely or partially implantable, with a negatively charged surface for repulsing bacteria, comprising a superficially bonded substance with a permanently negative excess charge, which substance, having no pharmacological effect and with the proviso that it is not heparin, is inert against cells of the human body and the bacteria contained therein, wherein the substance carrying negative charges is a sulfonic acid having an amino group and is covalently bonded to the surface via a peptide bond and deprotonated as well as the resulting negative charge being stabilized by the establishment of a mesomerism.