use of a pharmaceutical composition for the local treatment or prevention of a tissue infection at an infection site , the pharmaceutical composition comprising at least two different antibiotics of group a or pharmaceutically acceptable derivatives thereof , or an antibiotic of group a and at least one antibiotic of group b or pharmaceutically acceptable derivatives thereof . group a comprises primarily intracellular active antibiotics working as inhibitor of bacterial rna polymerase ; as inhibitor of gyrase ; or as inhibitor of bacterial protein synthesis . group b comprises primarily extracellular active antibiotics working as inhibitor of bacterial cell wall synthesis ; or inhibitor of bacterial protein synthesis ; or by direct destabilisation or rupture of the bacterial cell wall .