What does a microbiologist do, and why is this career important? Microbiologists study microorganisms, such as bacteria, viruses, and fungi, across a range of industries. Their work may include identifying microorganisms that affect health and the environment, developing antibiotics and vaccines, and conducting research. In this virtual career simulation, step into the role of a medical microbiologist as you investigate a bacterial infection and explore the skills these scientists use to guide life-saving diagnoses and treatment.