This case relates the story of two fictional college students, Kristen and Brent, who discover that they are infected with Staphylococcus aureus. Brent recovers after using an antibiotic, but Kristen does not. It is later confirmed through testing that she is infected with methicillin-resistant Staphylococcus aureus (MRSA). Students hypothesize about the difference between the two bacterial infections and the idea of antibiotic resistance is introduced. Students then use a bioinformatics tool to identify the antibiotic resistant organism. As students confirm that one bacterial infection is due to an antibiotic resistant organism, the discussion focuses on the development of antibiotic resistance. The case study is primarily designed for students in general biology courses and is particularly useful for students in microbiology. In a general biology course, it can be taught alongside evolution while, in a microbiology course, it can be used to illustrate antibiotic resistance.