Practical measures to control device-related bacterial infections.

Direct examination of medical devices that have been foci of chronic device-related bacterial infections has shown that the causative organisms grow predominantly in slime-enclosed biofilms. These adherent biofilms are inherently resistant to host defences (antibodies, phagocytes) and to conventional antibiotic therapy. Device-related infections can be prevented by careful cleaning and sterilization of the device, and by the avoidance of any manipulations that would allow the formation of even the most rudimentary biofilm prior to implantation. Once a device-related infection has become established, both the Minimum Inhibitory Concentration (MIC) and the Biofilm Eliminating Concentration (BEC) of the causative organism must be determined and therapeutic strategy must aim at the use of the MIC to control the acute phase caused by planktonic bacteria and of the BEC to eliminate the biofilm nidus of infection. The removal of the colonized device should be considered early in the course of treatment if the BEC cannot be delivered to the colonized device. We describe a new bioelectric technology presently in the in vitro stage of development which, if it can be reproduced in vivo, will be very effective in the prevention and control of device-related bacterial infections.