A bacterial pre-concentration and detection system generally includes a collection tube (110), a sensor (120) at the bottom of the collection tube, a moveable stopper (130) initially located toward the top of the tube, a piston (300) operatively connected to a robot for moving the stopper up or down the inside of the collection tube, and a hollow needle (400) penetrating the stopper and creating fluid communication with the inside of the collection tube. The system allows for the sample to be collected, lysed, centrifuged, concentrated, and interrogated with regard to the presence or absence of microorganisms with minimal steps and with a reduction in the time-to-detection, compared with conventional growth-based bacterial detection systems.