Animals Article Disease Models, Animal Gram positive bacterium Mice Mice, Transgenic Soft Tissue Infections Staphylococcal Infections Staphylococcus aureus Staphylococcus infection abscess animal bacteria bacterial clearance bacterial colonization bacterial endocarditis bacterial strain bacterial toxin bacterial transmission bioluminescence collagen disease model fibrin fluorescence analysis immune evasion immune response in vivo study macrophage mouse mouse model