As a consequence of the increasing

As a consequence of the increasing rates of resistances, each novel anti-infective agent reaching approval by the regulatory authorities is highly welcome. New drugs should not show cross resistances with commonly used antibiotics. In case of novel antibiotics, i.e. compounds which interfere with bacterial viability, a more or less rapid appearance of resistances can be expected. In order to provide sufficient effective antibiotic therapies, a continuous development of antibiotics is mandatory. Natural products are a valuable source of novel antibiotic agents. Moreover, approaches that do not interfere with cellular viability have drawn increasing attention. Blockers of bacterial virulence raise the hope that the development of resistant strains is significantly slowed down compared to antibiotics due to the lack of a direct bactericidal selection pressure. Single-target pathoblockers can act either through directly inhibiting the function of a virulence factor (e.g. elastase) or by interfering with the biosynthesis of the factor itself (e.g. PvdQ inhibitors as pyoverdine blockers). In case of these compounds, it will be important to evaluate their potential in disarming P. aeruginosa’s manifold virulence. It is possible that a combination of pathoblockers is needed for effective anti-virulence treatment. Interfering with the regulation of virulence for example with QSIs would address such a simultaneous anti-virulence strategy against a collection of virulence factors and seems promising (see chapter 2.2.2