All animal experiments were performed in accordance with University of Miami Animal Care and Use Committee guidelines. Animal's genotype was blinded prior to the experiment to limit bias. Our methodology was adopted from references (Cheng et al., 2009 (link); Wanke et al., 2013 (link)). In brief, all mice were shaved and tape-stripped (7 applications) with Transpore tape (3M, Minneapolis, MN, United States). This level of tape stripping did not create a wound, but was sufficient to disrupt the epidermal barrier. An inoculum of 109 MRSA strain CLP 153 in 0.02 ml of phosphate-buffered saline (PBS) or PBS control was added to ∼1 cm2 of skin and the area bandaged with plastic sheet and overwrapped with dressings of Transpore tape and Nexcare waterproof tape (3M) for 6 hr, at which time the bandage was removed. Mice were weighed daily throughout the experiment; animals were euthanized after greater than 30% weight loss.
For CFU enumeration, mice were sacrificed either 6 or 12 days after infection, cardiac puncture was performed and organs were harvested, weighed, and homogenized using a potter homogenizer in ddH2O with 0.05% Triton X-100. The homogenates were diluted and plated on TSA II plates (kanamycin and oxacillin selection). All samples were normalized based on weight.
For CFU enumeration, mice were sacrificed either 6 or 12 days after infection, cardiac puncture was performed and organs were harvested, weighed, and homogenized using a potter homogenizer in ddH2O with 0.05% Triton X-100. The homogenates were diluted and plated on TSA II plates (kanamycin and oxacillin selection). All samples were normalized based on weight.