SIM (sulfide, indole, motility) medium is an example of a multi-test medium, that is, it tests more than one aspect of the bacterium’s metabolism at a time. In this case, the production of hydrogen su...SIM (sulfide, indole, motility) medium is an example of a multi-test medium, that is, it tests more than one aspect of the bacterium’s metabolism at a time. In this case, the production of hydrogen sulfide, the formation of indole, and motility.