The present invention relates to a device comprising a sample receiving appliance, a receiving appliance for test organisms, preferably for a suspension comprising test organisms, in particular for a bacterial suspension, and a jet pump appliance, wherein the jet pump appliance is, or can be brought, into active connection with the receiving appliance, and wherein the jet pump appliance is designed and installed in order, by means of a propellant medium having a higher pressure than atmospheric pressure at the location of installation of the device to spray test organisms in the form of an aerosol in the direction of the sample receiving installation, wherein the device has an installation for controlling a reproducible pressure of the propellant medium during the spraying of the test organisms and also the use of a device according to the invention.