Disinfection of surgical instruments

Abstract

The degree of bacterial contamination of surgical instruments after operations and its reduction by cleaning and/or disinfection has been determined. Approximately 60 per cent of used instruments carried <10 1 micro-organisms, 80 per cent <10 2 and 90 per cent <10 3; and whether the operations were clean, clean-contaminated, contaminated or dirty did not significantly affect the microbial load. The contamination was not reduced by soaking instruments for 1 h in detergent, but an hour's immersion in a phenolic disinfectant reduced the levels to 80 per cent with <10 1 organisms and 98 per cent with <10 2. Similar reductions were obtained with a washer/ disinfector with a final rinse of water at >85 °C; and even better results with a different washer/disinfector without the final hot water rinse. The latter machine presumably had a better cleaning action. Instruments for manual processing should be disinfected before cleaning to minimize contamination of the cleaners' hands. However, they should preferably be processed in an efficient instrument-washer, which may not need a specific disinfection cycle, but must remain tightly closed to prevent contaminated splashes or aerosols.