The present invention relates to a method of identifying a compound useful for the treating, reducing or preventing a pathogenic infection caused by a microorganism and to the use of the PqsD protein or a functional fragment or variant thereof for the identification of a compound having said effect.本發明係有關鑑定用於治療、減輕或預防由微生物引起之病原性感染之化合物的方法,及有關使用PqsD蛋白質或其功能性片段或變異體鑑定具該作用之化合物之用途。