Endoscope Reprocessing Research Articles

Manual cleaning and disinfection of flexible endoscopes—an approach to evaluating a combined procedure

Compliance in endoscope reprocessing is unsatisfactory worldwide. The success of the reprocessing procedure relies upon both disinfection and cleaning. Products for instrument disinfection have to be tested accordingly. However, there is still no accepted standard against which to test the result of the cleaning procedure. Different strategies for endoscope reprocessing are possible: one-or two-step procedures. The decision for the method chosen strongly depends on the possibilities in individual hospitals. Products based on glutaraldehyde should not be used if it is not absolutely certain that instruments are already clean. There has to be an awareness that instruments are not designed for easy cleaning. A one-step procedure with products based on aliphatic amines could be an alternative. Methods of assessing such a procedure are suggested.

Efficacy of high-level disinfectants for reprocessing GI endoscopes in simulated-use testing

Background: There has been recent public concern regarding the adequacy of current practices for flexible endoscope reprocessing. High-level disinfection is defined by the Food and Drug Administration (FDA) as a minimum of 6-log reduction of mycobacteria under a worst-case scenario. Several agents are currently approved by the FDA, but published data on their relative efficacies against mycobacteria are lacking. The objective of this study was to determine the efficacy of these agents for high-level disinfection. Methods: In simulated-use testing, video endoscopes (5 colonoscopes and 5 duodenoscopes) were each inoculated with 9.0 × 10 7 colony-forming units of Mycobacterium chelonae. Cleaning was performed by using a standardized protocol. Each endoscope was then subjected to chemical disinfection with Cidex (2.0% glutaraldehyde) at 20°C for 20 minutes, Sporox (7.5% hydrogen peroxide) at 20° for 30 minutes, and Steris 20 (0.2% peracetic acid) at 50°C to 56°C for 12 minutes using the Steris System 1 processor. Although not FDA-approved, tests were also conducted by using 70% isopropyl alcohol at 20°C for 20 minutes. These results were compared with disinfection with ethylene oxide gas. All channels were sampled for M chelonae before and after manual cleaning and after disinfection. Results: Cleaning alone resulted in an average log reduction of 3. Cidex, Sporox, Steris 20, ethylene oxide gas, and isopropyl alcohol, in combination with manual cleaning, each achieved a 6-log or greater reduction of the mycobacterial inoculum. No organisms were recovered from any channel after reprocessing with ethylene oxide and Steris 20. Conclusions: Commercially available high-level disinfectants are equally efficacious for reprocessing flexible GI endoscopes when used in conjunction with cleaning and in accordance with recommended guidelines.

Pitfalls in endoscope reprocessing: brushing of air and water channels is mandatory for high-level disinfection

Background: Endoscopic transmission of pathogens has been reported. Guidelines have been formulated concerning the risk of infection via contaminated suction and accessory channels. Contamination of the other 2 channels for air and water has not been demonstrated. These channels were examined to clarify whether they require cleaning. Methods: Endoscopes used for examinations were divided into 2 groups. Group A endoscopes (n = 20) were brushed along the air and water channels. Group B endoscopes (n = 22) were not. After machine reprocessing, specimens were obtained for bacterial culture. The residual protein was measured in the 2 channels by using amido black 10B dye, and results were compared between the 2 groups. Results: With regard to the air channel, there were no contaminated endoscopes detected in either group. For the water channel, 1 endoscope in group B was positive whereas there were none positive in group A. With regard to quantification of residual protein, brushing diminished the level in both the air and the water channels. Conclusion: The air and water channels can become contaminated. Brushing every channel is mandatory for high-level disinfection. A redesign of the fundamental structure of endoscopes is proposed. (Gastrointest Endosc 2001;53:165-8.)

The clinical risks of infection associated with endoscopy.

The cleaning of flexible endoscopes is difficult and time consuming. Any method of attempted sterilization or high level disinfection will fail if prior cleaning has been defective. Inadequate reprocessing of endoscopes may result in patient to patient transmission of serious bacterial and viral diseases or infection with endemic hospital pathogens. Antibiotic prophylaxis is required to prevent septicemia and bacterial endocarditis in high risk patients undergoing specific endoscopic procedures. Prevention of serious endoscopy-associated clinical infections requires strict compliance with detailed reprocessing protocols by specially trained nursing staff.

American Society for Gastrointestinal Endoscopy-Society of Gastroenterology Nurses and Associates Endoscope Reprocessing Guidelines

Adequate endoscope reprocessing is one of the most essential functions in any endoscopy setting. Standards and guidelines for reprocessing endoscopes have been established by the Society of Gastroenterology Nurses and Associates (SGNA) and the American Society for Gastrointestinal Endoscopy (ASGE). These standards pertain to any setting in which gastrointestinal endoscopy is performed. Endoscope reprocessing that meets the established standard of practice helps to ensure a patient-ready instrument for all patients, reduces the risk of disease transmission to practitioners and staff, and helps to prolong the life of the endoscope.

7038 Is automated cleaning as good as manual cleaning in the reprocessing of flexible gi endoscopes?

Cleaning is an essential step in the reprocessing of GI endoscopes. Because manual cleaning is tedious and technician dependent, automated cleaning may have some advantages over the manual method. In simulated use testing, the efficacy of automated cleaning (System 83-2+DT, Custom Ultrasonics) was compared with a standardized manual cleaning method previously reported by the investigators (Amer J Gastroenterol 1999;94:1546). The automated reprocessor simulates the mechanical effects of a brush or sponge by pulsing enzymatic solution through most channels at a frequency of 60 Hz, and against the exterior surface of the insertion tube at 40,000 Hz. METHODS: One Olympus CF100TL videocolonoscope was contaminated with a simulated soil consisting of 2 parts sterile milk powder, 10 parts fetal calf serum, 10 parts Mycobacteria chelonae, for a final mycobacterial concentration of 10 9 CFU/mL. The suction housing, air-water housing, valves, insertion tube, instrument channel and auxillary channel were independently inoculated, and then air-dried for 60 min prior to cleaning. The size of inoculum (total CFU) was established for each site through control experiments. Each inoculated site was flushed with sterile phosphate buffer solution; the effluent was poured through a 0.45μm membrane filter, cultured in Middlebrook 7H11 agar, and incubated for 10 days at 37° C. Three to five experiments were conducted for controls and for manual and automated cleaning methods using the same scope. RESULTS: See table. CONCLUSIONS: (1) In simulated use testing under worst-case scenario, automated cleaning achieved a 3 to 5 log reduction in mycobacterial bioburden, which was at least equivalent to standardized manual cleaning. (2) Manual cleaning of the auxillary channel is potentially problematic because its small channel caliber precludes the use of a cleaning brush. (3) Used in conjunction with rigorous manual cleaning, automated cleaning may add an extra margin of safety for reprocessing of flexible GI endoscopes.

3341 Single-use biopsy forceps: does sterility upon insertion prevent contamination at time of biopsy?

Background: It has been suggested that single-use biopsy forceps will prevent inter-patient transmission of infection during endoscopy. Passage of sterile forceps through the biopsy channel can lead to contamination, however, if the endoscope is inadequately reprocessed.We prospectively evaluated the potential for contamination of single-use biopsy forceps at various stages of endoscope reprocessing. Methods: A total of forty disposable biopsy forceps (Microvasive Inc., Natick, MA) were passed through the biopsy channels of ten colonoscopes at various stages of reprocessing. Ten forceps were passed through the channels prior to use on patients to establish a baseline of high-level disinfection. Ten forceps were passed directly after colonoscopy to confirm contamination with use. Ten forceps were passed after manual cleaning and flushing of the biopsy channel to evaluate the effectiveness of manual cleaning to reduce bioburden. Finally ten were passed through the biopsy channel after either a 2- or 20-minute soak in 2% glutaraldehyde (Cidex™, Johnson & Johnson, Arlington, TX). The forceps were then sealed in sterile plastic bags and 15 ml of soy broth was added. The suspension was passed through a 0.2-micron filter, and the filters were cultured. All cultures were incubated more than 48 hours. Results: Biopsy forceps underwent a total of 40 aerobic and 40 anaerobic cultures. TNTC gastrointestinal flora grew on 19 of 20 plates from biopsy forceps passed through colonoscopes immediately after use (one plate grew only 3 colonies). Persistent gastrointestinal flora was noted on 5 of 20 plates from forceps passed through colonoscopes after manual cleaning alone. No gastrointestinal flora was found on forceps after the colonoscopes were exposed to gluteraldehyde soaks of 2 or 20 minutes. Nonpathogenic organisms including diptheroids, staphylococcus, and streptococcus grew on 16 plates. Conclusions: 1) Disposable biopsy forceps are highly susceptible to contamination from passage through the biopsy channels of improperly cleaned endoscopes. 2) High-level disinfection of the colonoscopes in this study prevented contamination of the forceps with pathogenic organisms. 3) Proper endoscope reprocessing may be the most important factor in preventing inter-patient infection, whether new biopsy forceps or sterilized reusable forceps are utilized.

Non-United States Guidelines for Endoscope Reprocessing

A worldwide concern has emerged with regard to endoscope disinfection, and many gastrointestinal endoscopy associations have guidelines for proper disinfection of endoscopes and endoscopic accessories. They are not much different from those of the American Society of Gastrointestinal Endoscopy and include mechanical cleaning as the first and most important step followed by immersion in 2% glutaraldehyde for periods ranging from 5 to 20 minutes. Lack of compliance with these guidelines has been noted, however, in 20 to 70% of centers in Europe, the United Kingdom, Australia, and Asia. Automated disinfectors are being universally recommended to ensure better compliance. Two other improvements are use of peracetic acid as an alternative disinfectant and use of a disposable sheath over the endoscope.

Reconciliation of FDA and Societal Guidelines for Endoscope Reprocessing

Chemical sterilants are used to high-level disinfect semicritical medical devices such as flexible endoscopes. For the chemosterilant to obtain a high level disinfection claim, The Food and Drug Administration requires demonstration of a 6-log reduction of myobacterial inoculum under worst case conditions (2% horse serum added to test sterilant). This testing requirement has led to label product claims of 45 minutes immersion times at 25 degrees C. Review of the scientific data suggests that at least an 8-log reduction in contamination with thorough instrument cleaning, followed by chemical disinfection for 20 minutes immersion at 20 degrees C will achieve high-level disinfection.

Automated endoscope reprocessing; sterile setup monitoring; air exchange rates; cleaning ice machines

Automated endoscope reprocessing; sterile setup monitoring; air exchange rates; cleaning ice machines

Efficacy of conventional endoscopic disinfection and sterilization methods against Helicobacter pylori contamination.

Iatrogenic transmission of Helicobacter pylori via contaminated endoscopic devices is well documented. Despite the prevalence of this infectious agent, few controlled studies have investigated the major factors that impact on reprocessing of endoscopes contaminated with H. pylori. An endoscope (Pentax) was contaminated with 108 cfu/ml of H. pylori in 5% bovine calf serum as standardized inoculum. The endoscope then was passed through one of eight arms (five repetitions per arm = 40 total runs), as follows: 1, recovery control (no cleaning or disinfection); 2, manual cleaning alone; 3-5, manual precleaning followed by either 10-, 20-, or 45-minute exposure to 2% glutaraldehyde and ethanol (ETOH) drying; 6, manual cleaning followed by automated reprocessing by STERIS System; 7 and 8, automated reprocessing by STERIS with and without active peracetic acid sterilant (wash-off control). Suction-biopsy channels and air-water channels were harvested for microbiological culture. Control runs recovered more than 1 x 106 cfu per site, confirming the viability of the test organism and the adequacy of the biological burden for challenge. When instruments underwent manual cleaning alone (without subsequent disinfection), test organisms remained in 40% of runs at the air-water site. Manual cleaning followed by 10-, 20-, or 45-minute glutaraldehyde exposure and ETOH drying removed all test organisms from all sites in all runs (i.e., 100% disinfection). The automated STERIS system with or without active peracetic acid sterilant also removed all test organisms from all sites in all runs, as did manual cleaning followed by STERIS use. Manual cleaning alone does not effectively remove H. pylori from an endoscope. Current joint association recommendations for minimal disinfection (manual cleaning followed by at least 20 minutes of immersion in glutaraldehyde and ETOH drying) are effective in preventing cross-transmission of H. pylori. Reprocessing using the automated STERIS system according to manufacturer's recommendations also is highly effective in sterilizing endoscopes contaminated with H. pylori.

Standards for Infection Control and Reprocessing of Flexible Gastrointestinal Endoscopes

Standards for Infection Control and Reprocessing of Flexible Gastrointestinal Endoscopes

Flexible gastrointestinal endoscopic reprocessing

Two articles in this month's journal focus on specific areas of controversy in the reprocessing of flexible gastrointestinal endoscopes between patient use. In the study by Urayama et al.,1 the authors demonstrated that manual cleaning of endoscopes heavily contaminated with laboratory-cultured mycobacteria (102 colony forming units per instrument) resulted in greater than a 104 log reduction in numbers of viable cells recovered when the biopsy channels of five instruments were sampled. However, using two laboratory assay methods, they also showed that extending the endoscope exposure time in 2% alkaline glutaraldehyde from 10 to 20 minutes (presumably at room temperature) did not completely eradicate the mycobacterial inocula in the channels.

Endoscope Maintenance and Repairs

A well organized approach to endoscope maintenance and repair is a necessity for cost efficiency. More than 20 years’ experience in this area is presented. The major subjects addressed are the reprocessing of endoscopes and accessories, storage of endoscopes, inspection and troubleshooting steps, record keeping, and analysis of instrument use and repairs.

Variability in reprocessing policies and procedures for flexible fiberoptic endoscopes in Massachusetts hospitals

Concern is increasing regarding the risk of transmission of blood-borne pathogens by means of improperly reprocessed medical devices. On-site surveys of policies and practices were performed in 18 reprocessing areas in eight randomly selected hospitals in Massachusetts to assess current practices for reprocessing of flexible fiberoptic endoscopes. Manufacturers' and internal written protocols, were reviewed, employees were interviewed, and procedures were observed. Reprocessing included high-level disinfection in 17 of 18 areas, with 16 areas using 2% glutaraldehyde; ethylene oxide gas sterilization was used in one area. Considerable interhospital and intrahospital variability was found in high-level disinfection procedures, including equipment, contact time (range 10 to 45 minutes), disinfectant testing, and rinsing. Disinfection of internal channels was inadequate in three areas, recommended sterilization of biopsy forceps was not performed in five, and written protocols were unavailable in three. Ad hoc deviation from established written or verbal protocols occurred in eight areas during reprocessing of flexible fiberoptic endoscopes from patients known to have AIDS; ethylene oxide sterilization was used in seven areas and a separate device was used in one. Interviews with personnel revealed that lack of knowledge of high-level disinfection contributed to the discrepancies between policy and practice. We conclude that reprocessing of flexible fiberoptic endoscopes is inconsistent and potentially ineffective. Knowledge that a flexible fiberoptic endoscope was used for a patient with AIDS influences practice.