Manual Cleaning, Use of AER for Scopes Ensures Prevention of Transmissible Organisms

The growing prevalence of infectious diseases among patients, including HIV infection, increases the risk of transmission of an infection during endoscopic procedures. In 2009, the first three cases of HIV transmission through colonoscopy were reported in the U.S.

Researchers from Moscow studied colonoscopes processed manually and via automated endoscope reprocessing through microbiologic determination of total bacterial contamination, lgCFU/ml. Swab samples taken from instrumental channels of colonoscopes immediately after the procedure (sample 1), after mechanical brushing of channels (sample 2), and after completing high-level disinfection (HLD) or a complete reprocessing cyclein the Automatic Endoscope Reprocessor (AER) [ASP Johnson & Johnson] (sample 3). Swabs taken from 48 colonoscopes were studied.

Bacterial contamination of instrumental channels (samples 1, 2, and 3) in 17 colonoscopes after their use, brushing, and processing in AER was 8.7 (8-10), 4.74 (3.32-6.3), and 0 lgCFU/ml, respectively. Bacterial contamination (samples 1 and 3) of 16 colonoscopes processed in AER only was 8.87 (8-9.7) and 3.8 (2.7-4.85) lgCFU/ml, respectively. Bacterial contamination (samples 1, 2, and 3) of 15 colonoscopes cleaned manually was 8.99 (8-10.4), 5.2 (3-6.7), and 2.9 (2.7-4.1) lgCFU/ml, respectively.

Grenkova, et al. concluded that processing of colonoscopes in the AER, after preliminary brushing of channels, is most reliable and effective. In 2008, the researchers say they proved that the endoscopes after use on HIV-infected patients represent danger of infection; HIV was isolated in the MT-4 human T-lymphoblastoid cells in 33 of 35 (94.3 percent) samples taken from instrumental channels of endoscopes directly after use and in three samples (8.6 percent) after completing HLD. All cases of ineffective cleaning were associated with violations of national standards. Their research was presented at the International Conference on Prevention & Infection Control (ICPIC) held in Geneva, Switzerland June 29-July 2, 2011.

Reference: T Grenkova, E Selkova, V Aleshkin and A Melkumyan. Ensuring infectious safety of colonoscopy. Presentation at International Conference on Prevention & Infection Control (ICPIC). BMC Proceedings 2011, 5(Suppl 6):P309doi:10.1186/1753-6561-5-S6-P309