Bacterial adhesion to intravenous cannulae: influence of implantation in the rabbit and of enzyme treatments

Abstract

SUMMARYComparison was made of the adhesion ofStaphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Klebsiella aerogenesandPseudomonas aeruginosato six types of intravascular cannula material. Adhesion to materials removed from rabbit tissues did not differ significantly between types of material or between bacterial species. In contrast, major differences were found when unimplanted materials were examined; the overall rank order of adhesiveness of bacteria to unimplanted materials (S. epidermidis > P. aeruginosa > S. aureus≫K. aerogenes > E. coli) was highly significant (F= 13·0,P< 0·0005), and although no single material was consistently least attractive to all micro-organisms, FEP-Teflon and PTFE-Teflon showed significantly lower overall affinity for bacteria than other materials (P < 0·001); all species showed a significant preference for a silicone polymer (P < 0·0005). The nature of the bacterial surface structures responsible for adhesion were investigated by the actions of pronase and mixed glycosidase, which produced significant respective decreases and increases in adhesion of staphylococci to unimplanted materials; their effects on the Gramnegative bacilli were less consistent.