University of Geneva - Faculty of Medicine

The regulation of quorum-sensing dependent virulence genes in Pseudomonas aeruginosaThe mechanism of function and targets of DksAThe overexpression of the dksA gene interferes with the quorum-sensing circuitry primarily by interfering with the transcription of rhlI leading to reduced C4-HSL autoinducer production.A P. aeruginosa dksA mutant is being constructed to determine whether this affect the virulence of P. aeruginosa.Quorum-sensing inhibition by macrolidesSub-inhibitory concentrations of azithromycin inhibit the quorum-sensing circuitry and lead to a reduction of virulence factor production. Therefore macrolides might in the future have a significant role in the treatment of chronic infections with P. aeruginosa.The importance of stringent response for a cell-density independent activation of quorum-sensingThe quorum-sensing circuitry of P. aeruginosa can be activated a low cell density by the nutrient starvation induced stringent response. This is the first environmental signal demonstrated to activate quorum-sensing independently of cell-density.