Efficacy of conventional endoscopic disinfection and sterilization methodsagainst Helicobacter pylori contamination

Background. Iatrogenic transmission of Helicobacter pylori via contaminated endoscopic devices is well documented. Despite the prevalence of this infe ctious agent, few controlled studies have investigated the major factors th at impact on reprocessing of endoscopes contaminated with H. pylori. Materials and Methods. An endoscope (Pentax) was contaminated with 10(8) cf u/ml of H. pylori in 5% bovine calf serum as standardized inoculum. The end oscope then was passed through one of eight arms (five repetitions per arm = 40 total runs), as follows: 1, recovery control (no cleaning or disinfect ion); 2, manual cleaning alone; 3-5, manual precleaning followed by either 10-, 20-, or 45-minute exposure to 2% glutaraldehyde and ethanol (ETOH) dry ing; 6, manual cleaning followed by automated reprocessing by STERIS System ; 7 and 8, automated reprocessing by STERIS with and without active peracet ic acid sterilant (wash-off control). Suction-biopsy channels and air-water channels were harvested for microbiological culture. Results. Control runs recovered more than 1 x 10(6) cfu per site, confirmin g the viability of the test organism and the adequacy of the biological bur den for challenge. When instruments underwent manual cleaning alone (withou t subsequent disinfection), test organisms remained in 40% of runs at the a ir-water site. Manual cleaning followed by 10-, 20-, or 45-minute glutarald ehyde exposure and ETOH drying removed all test organisms from all sites in all runs (i.e., 100% disinfection). The automated STERIS system with or wi thout active peracetic acid sterilant also removed all test organisms from all sites in all runs, as did manual cleaning followed by STERIS use. Conclusion. Manual cleaning alone does not effectively remove H. pylori fro m an endoscope. Current joint association recommendations for minimal disin fection (manual cleaning followed by at least 20 minutes of immersion in gl utaraldehyde and ETCH drying) are effective in preventing cross-transmissio n of H. pylori. Reprocessing using the automated STERIS system according to manufacturer's recommendations also is highly effective in sterilizing end oscopes contaminated with H. pylori.