I have worked in hospitals for many years never heard of a bacterial big wig, but a few professionals come to mind
There is the infectious disease Dr who diagnoses and treats the offending bacteria.
There are the Microbiologist in the lab where the samples are sent for identification
There are the infection control nurses who monitor the types of bacteria circulating in the hospital, and assist the Dr. and floor nurses in treatment. They all play a big role in infection control, diagnosis, and treatment. From your classes and reading you should be able to select one of these.