BacterIaI adhesion is important in ecology as well as m biotechnology
In medicine, bactenal adhesion to solid surfaces plays a significant role m the development of implant-or catheter-related infections. In the laboratory, bacteria are generally cultivated and studied as cell suspensions in liquid media. The natural environment, however, is more complex It has been reported in a number of studies that bacteria growing in blofilms are more resistant to biocides than those grown m culture. The present study mvestlgated the colomzatlon of an inert solid phase TygonR m an original system with Esckr~chicr co/r ATCC 10 536. m a continuous flow of fresh me&urn under Iron-hmiting conchtlons and sufficiently diluted to preclude the growth of suspended cells. The bactenedal activity of chlorhexlchne was examined against biofilms established under dynamic conditions. and was compared for the same strain m suspension. m compliance with AFNOR NFT 72-170 (static conditions). The adhering cells and the suspended cells in the eluates were evaluated by viable counts after 1, 2, 3, 4 and 5 days. The results of this study suggested that cells m blofilms were more susceptible to chlorhexidme than suspended cells. According to this model, the biofilms were less susceptible under dynamic conditions than under static conditions (AFNOR). The actlvlty of chlorhexidme at the concentration normally used for bladder washouts (200 pg ml ' I against Eschrr~hrct coli was discussed.