Inadequate drying of endoscope channels is a possible cause of microbial proliferation during storage. This risk could be reduced by any procedure or process used to dry endoscope channels and control storage conditions. The efficacy of a drying and storage cabinet (Hysis Medical) was tested on three different endoscopes: a colonoscope (Olympus); duodenoscope (Fujinon) and an enteroscope (Pentax), all of which had been artificially contaminated with a suspension of Pseudomonas aeruginosa CIP 103467. Changes to the residual internal contamination level of these endoscopes when stored inside or outside the drying cabinet for 12, 24, 48 or 72 h were compared. When stored in the drying and storage cabinet, microbial contamination levels on endoscopes were lower than the number of bacteria initially introduced and could decrease considerably thereafter. For endoscopes stored outside the drying storage cabinet, microbial numbers were stable or even increased. These data demonstrate the advantages of such endoscope drying/storage cabinets that limit the risk of bacterial proliferation in the internal channels of endoscopes during storage, and which ensure that the disinfection level reached at the end of the reprocessing procedure is maintained.

Endoscope reprocessing is a multi-stepped process that renders a contaminated endoscope safe for reuse. Its steps include meticulous cleaning, complete immersion in a liquid chemical sterilant (LCS) or disinfectant to achieve high-level disinfection (or "liquid sterilization"), water rinsing, and proper handling and storage. Surveys and reports indicate that not all health-care facilities dry their endoscopes after reprocessing. Endoscope drying can be easily, quickly, and inexpensively achieved by flushing the endoscope's internal channels, and wiping its external surfaces, with 70-90% ethyl or isopropyl alcohol, to facilitate drying after reprocessing, followed by compressed or forced air.

The medical literature was reviewed to evaluate the importance of endoscope drying to the prevention of disease transmission. Several national and international endoscope-reprocessing and infection-control guidelines and a public health advisory were also reviewed and compared for consistency and to evaluate the emphasis each places on endoscope drying. If a guideline recommends endoscope drying, this study clarified whether this step is recommended after reprocessing throughout the day (i.e., between patient procedures), before storage, or both. These guidelines were also reviewed to determine whether any of them recommend reprocessing endoscopes before the first patient of the day.

This review identified several published reports and clinical studies that demonstrate the significant contribution of endoscope drying to the prevention of disease transmission. This review also identified significant differences and inconsistencies regarding the emphasis different published guidelines and a public health advisory place on endoscope drying. Some guidelines recommend drying the endoscope after completion of every reprocessing cycle, both throughout the day and before storage, while others deemphasize its importance and recommend endoscope drying only before storage, if at all. Instead of recommending endoscope drying before storage, some guidelines recommend reprocessing endoscopes before the first patient of the day.

The finding that several guidelines are inconsistent with one another and that some are remiss and fail to recommend endoscope drying is of concern. Endoscope drying is as important to the prevention of nosocomial infection as cleaning and high-level disinfection (or "liquid sterilization"). Whereas wet or inadequately dried endoscopes pose an increased risk of contamination and have been associated with transmission of waterborne microorganisms and nosocomial infection, thoroughly dried (and properly cleaned and high-level disinfected) endoscopes have not been linked to nosocomial infection. Moreover, inconsistent guidelines can confuse reprocessing staff members and result in noncompliance, variations in the standard of care, and ineffective reprocessing. To minimize the risk of disease transmission and nosocomial infection, modification and revision of guidelines are recommended as required to be consistent with one another and to unconditionally recommend endoscope drying after completion of every reprocessing cycle, both between patient procedures and before storage, no matter the label claim of the LCS or disinfectant, the label claim of the automated reprocessing system, or the microbial quality of the rinse water. According to the medical literature, adoption of this recommendation may reduce the importance of not only monitoring the microbial quality of the rinse water, but also reprocessing endoscopes before the first patient of the day, both of which can be costly practices that a few guidelines recommend.

Endoscopes are used frequently for the diagnosis and therapy of medical disorders. For example, greater than 10000000 gastrointestinal endoscopic procedures are performed each year in the United States. Failure to employ appropriate cleaning and disinfection/sterilization of endoscopes has been responsible for multiple nosocomial outbreaks and serious, sometimes life-threatening, infections. Flexible endoscopes, by virtue of the site of use, have a high bioburden of microorganisms after use. The bioburden found on flexible gastrointestinal endoscopes following use has ranged from 10(5) to 10(10)CFU/ml, with the highest levels being found in the suction channels. Cleaning dramatically reduces the bioburden on endoscopes. Several investigators have shown a mean log(10) reduction factor of 4 (99.99%) in the microbial contaminants with cleaning alone. Cleaning should be done promptly following each use of an endoscope to prevent drying of secretions, allow removal of organic material, and decrease the number of microbial pathogens. Because the endoscope comes into intimate contact with mucous membranes, high-level disinfection is the reprocessing standard after each patient use. High-level disinfection refers to the use of a disinfectant (e.g., FDA-cleared chemical sterilant or high-level disinfectant) that inactivates all microorganisms (i.e., bacteria, viruses, fungi, mycobacteria) but not high levels of bacterial spores. The disinfection process requires immersion of the endoscope in the high-level disinfectant and ensuring all channels are perfused for the approved contact time (e.g., for ortho-phthaladehyde this is 12 min in the US). Following disinfection, the endoscope and channels are rinsed with sterile water, filtered water, or tapwater. The channels are then flushed with alcohol and dried using forced air. The endoscope should be stored in a manner that prevents recontamination. A protocol that describes the meticulous manual cleaning process, the appropriate training and evaluation of the reprocessing personnel, and a quality assurance program for endoscopes should be adopted and enforced by each unit performing endoscopic reprocessing.

Several outbreaks and pseudo-outbreaks of Pseudomonas aeruginosa and Serratia marcescens infections associated with bronchoscopy have been reported. We conducted an investigation of P. aeruginosa and S. marcescens isolates related to bronchoscopy at a community hospital.

We reviewed the records of all bronchoscopic procedures at the community hospital from July to October 2001. Environmental samples were obtained. Pulsed-field gel electrophoresis (PFGE) was performed on isolates of P. aeruginosa.

From July 1 to October 31, 2001, 66 bronchoscopic procedures were performed in 60 patients, and 43 specimens were obtained for bacterial culture; 20 of the specimens (47 percent) were positive for P. aeruginosa. Six (30 percent) of the specimens that were positive for P. aeruginosa also yielded S. marcescens. All 20 P. aeruginosa isolates were associated with procedures performed with three of four new bronchoscopes from the same manufacturer. Contrary to manufacturing specifications, the biopsy-port caps on all four bronchoscopes were easily removable, and P. aeruginosa was cultured from the biopsy ports of the three implicated bronchoscopes. The PFGE patterns of P. aeruginosa isolates from the bronchoscopes, patients, and two environmental samples were indistinguishable. One patient was hospitalized with P. aeruginosa pneumonia 11 days after bronchoscopy. The manufacturer reported a design change instituted in 1997, and production problems may have resulted in the distribution of bronchoscopes that did not meet specifications.

We documented contamination of bronchoscopes with P. aeruginosa and S. marcescens and possible infection of patients at a community hospital as a result of the inadequate disinfection of bronchoscopes because of a manufacturing defect.

The routine sampling of environmental surfaces within a healthcare facility is generally not recommended by the Centers for Disease Control and Prevention (CDC), the Association for the Advancement of Medical Instrumentation (AAMI), and several other healthcare organizations. There are a few circumstances, however, for which some organizations do recommend this practice. For instance, the CDC and the Association for Professionals in Infection Control and Epidemiology (APIC) recommend environmental sampling as clinically required during an outbreak investigation. The CDC and AAMI also recommend routine sampling of the rinse water used during hemodialyzer (but not endoscope) reprocessing. The rationale for this recommendation is based in part on reports of pyrogenic responses, patient infections, and bacteremia due to waterborne, gram-negative bacteria during hemodialysis. To determine whether the basis for this rationale might similarly apply to the rinse water used during endoscope reprocessing, the Food and Drug Administration's medical device reporting database, the endoscope reprocessing literature, and other sources were reviewed. The results of this review indicate that nosocomial outbreaks linked to endoscopes contaminated with gram-negative bacteria have been frequently reported. As a result, for several reasons, including to minimize the risk of patient infection due to gram-negative bacteria following endoscopy, this article recommends routine microbiologic sampling of the rinse water used during endoscope reprocessing.

In June 1998, a questionnaire was mailed to approximately 2,900 healthcare professionals to assess current instrument reprocessing and infection control practices and determine whether they have changed during the past decade. Surveys were returned from 146 respondents whose facilities performed gastrointestinal endoscopy. Most respondents were registered nurses and almost all worked in healthcare facilities located in the United States. More than 75% of the respondents reported that infection control practices in endoscopy have improved during the past 10 years. Most respondents used glutaraldehyde to reprocess flexible endoscopes. Immersing endoscopes for 20 minutes at room temperature was commonly practiced. Almost 75% of respondents used an automated device to reprocess flexible endoscopes. Most respondents terminally rinsed the endoscope's channels with 70% alcohol followed by forced-air drying. Few respondents outsourced instruments to a commercial reprocessing company and almost 50% reused disposable items. While some practices in endoscope reprocessing have changed during the past several years, others have not. In general, infection controls appear to have improved during the past decade, with the possible exception of a trend to reuse single-use items.