Self-disinfecting plastics for intravenous catheters and prosthetic inserts.

A disinfectant (2,4,4'-trichloro-2'-hydroxydiphenyl ether: Irgasan, Ciba-Geigy) was incorporated into plastic washers fabricated from ethylvinyl acetate (EVA), polyethylene, polypropylene or TPX. Plastics containing 0.2 and 2% Irgasan gave zones of inhibition on nutrient and blood agar plates seeded with micro-organisms (Staphylococcus aureus, Staph. epidermidis, Escherichia coli, Proteus mirabilis or Candida albicans) even after thorough washing. Exceptionally, C. albicans was inhibited only by 2% Irgasan, and EVA gave good inhibition only against the staphylococci. Similar washers of each plastic were implanted subcutaneously into the flanks of rabbits; before insertion each was washed, had thread woven into it and was surrounded by a plasma clot containing 2 X 10(8) Staph. aureus. All the plastics without Irgasan gave rise to abscesses, none of the plastics impregnated with 2% Irgasan did, though from 2 out of 12 sites small numbers of Staph. aureus were isolated at post mortem. Using either clinical or bacteriological criteria, the results were highly significant (P less than 0.00001 and P less than 0.001 respectively), demonstrating the effectiveness of this technique in preventing plastic-associated infection.