A method for reducing or removing biofilm on a target tissue or prosthesis surface includes providing a coupling space or antechamber between the operative tip or end of an ultrasonic probe and a target treatment surface, the space or antechamber being fillable with a liquid irrigant to transmit ultrasonic vibration and facilitate extraction of biofilm fragments including potentially pathogenic particles. A second phase of treatment in the case of organic tissue involves the attachment of one or more ultrasonic transducers to a patient over or near a surgical treatment site after surgery is terminated. Each applied ultrasonic transducer is used to vibrate the patient's tissues at the treatment site to disrupt biofilm formation.