RESUMEN
One approach to identify new drugs with antimicrobial activities is to screen large libraries of molecules directly for their capacity to block the growth of bacterial or fungal monocultures. A more relevant way to assess both a product's efficacy and its potential cytotoxicity is undoubtedly to use an in vivo infection system. Testing banks containing thousands of natural or chemically synthesized molecules with rodents is generally neither desirable nor feasible. Therefore, invertebrate model organisms could represent a valuable alternative. In this review, we present the worm C. elegans as a suitable host model for the evaluation and characterization of drug effects in a pathogenesis context. This simple organism has been of great value in many fields of biology and is currently intensely used in studies of host-pathogen interactions. Infection of C. elegans induces a number of defense mechanisms, some of which are similar to those seen in mammalian innate immunity. Further, it has been demonstrated that several microbial virulence mechanisms required for full pathogenicity in mammals are also necessary for infection in nematodes. Based on these facts, a number of innovative antimicrobial drug screens have been carried out successfully and the development of new tools to monitor the interaction between worm and microbes in vivo opens promising perspectives.