Murine model of cutaneous infection with Streptococcus pyogenes.

Despite the medical advances achieved during the last century to fight against bacteria, viruses, fungi and parasites, infectious diseases are still a major cause of death, disability, and social and economic upheaval for millions around the world. Challenges remain in countering microorganisms even where antibiotics and vaccines are available. Much remains to be learned about basic aspects of the host-pathogen relationship and the complexity of the immune response to infection. Animal models represent a powerful tool to dissect the host response to infection, as well as the pathogenesis of the microbe. One of the advantages of using animal models is that both genetic and environmental factors that may influence the course of an infection can be controlled, allowing a precise cause-effect analysis of the host-pathogen interactions. In addition, there are no real alternatives to whole animal models in the study of integrative physiology and dynamic pathophysiologic alterations. The use of animal models has also proven invaluable for testing the efficacy of experimental antimicrobial agents and their therapeutic regimes. The mouse model is the most widely used for many reasons, including its cost effectiveness, the high number of immunological reagents available for this species, and the relative ease of biocontainment. Mouse strains with specific properties such as transgenic mouse strains with gene insertion or targeted mutation (knock-out) are very effective tools for studying the role of specific genes controlling the immune response to infectious pathogens. Murine models will remain the most appropriate tool for evaluating new therapeutic strategies for the treatment of various diseases. The closer the model is adapted to the human disease, the more reliable will be the results.In this chapter, the experimental procedures required to establish a mouse model of cutaneous and soft tissue infection are detailed. This model has provided invaluable insights into the pathogenicity of the agent for the human host.