Methods of disinfecting endoscopic material: results of an international survey

[Five years of the Robert Koch Institute guidelines for reprocessing of flexible endoscopes. A look back and a look forward]

In a short review the national and international reception of the German guidelines for reprocessing flexible endoscopes is presented. The recommendations of the guidelines are discussed in view of recent knowledge on old problems such as prion inactivation and new infectious diseases and new microorganisms such as SARS, avian influenza and C. difficile. New disinfectants and new methods for endoscope disinfection are mentioned, the importance of careful cleaning is underlined. The German guidelines of the Robert Koch Institute and the US Multi-Society guidelines, published in 2003, are compared. The discrepancies concerning recommendations for water quality for final rinsing and need of microbiological controls of endoscope reprocessing are stressed. Aspects not mentioned in the German guidelines, e.g. duration of storage after reprocessing and risk of infection transmission by the endo-washer, are discussed.

Current issues in endoscope reprocessing and infection control during gastrointestinal endoscopy

The purpose of this article is to review the evidence regarding transmission of infection during gastrointestinal endoscopy, factors important in endoscope reprocessing and infection control, areas to focus on to improve compliance, and recent developments and advances in the field.

German guidelines for reprocessing endoscopes and endoscopic accessories: guideline compliance in Frankfurt/Main, Germany

Guidelines for reprocessing flexible endoscopes have been published in many countries. The present survey investigated compliance with German guidelines in all hospitals and private practices in Frankfurt/Main, Germany. In 2003, all endoscopic units in Frankfurt/Main [15 hospitals and 23 private practices (10 large practices performing >1,000 endoscopies/year and 13 small practices performing <1,000 endoscopies/year)] were visited by members of the Public Health Service and assessed using a checklist based on the recommendations of the German guidelines. In 2004, a re-evaluation took place, either by analysing the written reports of the institutions or by visiting them again. Meanwhile, one hospital had closed and three small practices had ceased performing endoscopy, so the re-evaluation encompassed 14 hospitals and 20 private practices. In 2003, hospital compliance with the guidelines was satisfactory but many problems were identified in private practices. Between 2003 and 2004, great improvements were made. By the end of 2004, 90% of private practices had adequate storage facilities for reprocessed endoscopes, and were performing reprocessing of bottles and tubes for air-/water-channel flushing correctly (2003: adequate storage 52%; correct reprocessing 74%). Sterilization of endoscopic accessories was satisfactory, and routine testing of endoscopes after reprocessing was performed in all private practices at the end of 2004 (2003: sterilization of accessories 57%; microbiological control tests 56%). In 2003, although hospital compliance with the guidelines was satisfactory, mandatory improvements were required in private practices, notably in smaller units. Infection control advice and the control of public health regulations resulted in the correction of most processing faults between 2003 and 2004.

Survey of gastrointestinal endoscope disinfection and accessory reprocessing practices in the Asia-Pacific region

Concern has been raised about the possibility of transmission of infection by gastrointestinal endoscope. This vexation may be related to reliability of the disinfecting techniques or to the compliance with the guidelines laid down for disinfection. There have been very few recent surveys examining the disinfection practices for gastrointestinal endoscopes and their accessories. This survey was undertaken to understand such practices in the Asia-Pacific region. A questionnaire was sent by post or electronic mail to 356 randomly selected endoscopy centres in the Asia-Pacific region. Responses were received from 38.7% of the centres. The survey showed that there were significant aberrations in the application of disinfection procedures. One-third of the respondents did not practise disinfection at the start of the day's session, 2.9% of the centres were not using a high-level disinfectant and 34.7% of the centres used a soak time in 2% glutaraldehyde of less than 10 min. At 40% of the centres, at the end of the day's session, forced air or alcohol was not used to dry the endoscopes. Reuse of accessories meant for single use was widely practised.

Disposable versus reusable biopsy forceps: a prospective cost evaluation

BACKGROUND

There is growing advocacy for the use of disposable medical accessories to reduce the risks of infection transmission. Their purchase costs can, however, be considered as prohibitive in an endoscopy unit operating under a cost-containment program. We therefore compared the costs of reusable and disposable biopsy forceps.

METHODS

From October 1995 to September 1997, biopsies were obtained in 7740 sessions. The evaluation of costs included purchase prices, repairs, cleaning (chemicals, equipment, technician time) and autoclaving costs in a centralized sterilization unit. For comparison, the lowest purchase price for disposable biopsy forceps was $26.90 in 1997.

RESULTS

A mean of 12 new reusable forceps were purchased every year for a total purchase price of $5460. A total of 315 biopsy sessions were performed per forceps (mean time life of 3 years per forceps, including 3 repairs). Yearly repair cost was $3308, equipment $1002, chemicals $3250, central sterilization $8333, and technician salary $4373. Total cost was $25,726 and cost per biopsy session was $6.65.

CONCLUSIONS

Total purchase and reprocessing costs for reusable biopsy forceps were 25% of those of disposable devices. The use of disposable biopsy forceps would have led to a yearly extra cost of $78,377 in the operation of our endoscopy unit.

Disposable-sheath, flexible gastroscope system versus standard gastroscopes: a prospective, randomized trial

BACKGROUND

Endoscopically transmitted infections due to inadequate disinfection are rare but well-recognized complications. A new prototype of a flexible, fiberoptic endoscope has been developed that uses a disposable sheath to cover and protect all working surfaces of the endoscope from contamination. The present study investigated the function, reprocessing, and hygienic status of this endoscope system in comparison with standard systems.

METHODS

In a prospective, randomized trial, 100 upper endoscopic procedures (50 standard, 50 sheathed) were performed. Analog rating scales were used to evaluate endoscopic performance and reprocessing. Reprocessing time, procedure duration, insertion depth, total instrument downtime, and problems occurring during the procedure were recorded. Microbiologic swabs were obtained from each endoscope.

RESULTS

Mean procedure duration was slightly longer with the sheathed system than with standard endoscope (9.9 vs. 8.4 min). Set up and reprocessing times, however, were significantly shorter with the Endosheath (8.9 vs. 48.4 min with the standard endoscope). The disposable-sheath endoscope system permits the rate of performance of procedures to be increased by a factor of up to 3.0. Both endoscopists and reprocessing personnel preferred the standard endoscope. No post-procedure sheath leakage or rupture was seen.

CONCLUSION

Our results suggest that the "disposable endoscope" may have important advantages in terms of decreased instrument turn-around time and potentially improved safety.

GI endoscopic reprocessing practices in the United States

BACKGROUND

Patient infection from contaminated gastrointestinal (GI) endoscopes can generally be attributed to failure to follow appropriate reprocessing guidelines. Recently, the Food and Drug Administration recommended a 45-minute exposure of GI endoscopes to 2.4% glutaraldehyde solutions heated to 25 degrees C. Simultaneously, the American Society for Gastrointestinal Endoscopy (ASGE), the American Gastroenterological Association, and the Society of Gastroenterology Nurses and Associates endorsed a reprocessing guideline that emphasized manual precleaning and recommended a 20-minute exposure to a 2.4% glutaraldehyde solution at room temperature. Since then, little information has become available regarding actual reprocessing practices in the United States.

METHODS

A previously developed questionnaire regarding endoscopic disinfection practices was mailed to randomly selected members of the ASGE.

RESULTS

The survey was sent to 730 members and 294 responded (40.3%). Appropriate manual cleaning (suctioning detergent through the accessory channel and brushing the channel and valves) is performed by 90.7% of respondents; 69.9% then use automated reprocessors for disinfection or sterilization. Glutaraldehyde is the most widely used chemical disinfectant; 85.3% use glutaraldehyde as one of their primary disinfectants. The most commonly used disinfection time with 2.4% glutaraldehyde is 20 minutes (83.9%) followed by 45 minutes (11.4%). Only 23.8% of users of 2.4% glutaraldehyde heat their solution; 59.6% of centers test disinfectant concentration daily or more frequently; 74.0% sterilize nondisposable forceps before use; 29.2% of centers re-use disposable endoscopic accessories (which are more frequently disinfected rather than sterilized). Twelve respondents reported cases of endoscopic cross infection.

CONCLUSIONS

A significant minority of endoscopy centers still do not completely conform to recent ASGE, American Gastroenterological Association, and the Society of Gastroenterology Nurses and Associates guidelines on disinfection, and they may not be appropriately disinfecting GI endoscopes. Rigid adherence to recommended guidelines is strongly encouraged to ensure patient safety.

Seroprevalence of immunoglobulin G antibodies against Helicobacter pylori among endoscopy personnel in Japan

BACKGROUND

The seroprevalence of immunoglobulin G antibodies against Helicobacter pylori in endoscopy personnel was determined to investigate whether gastrointestinal endoscopists and endoscopy nurses in Japan are at an increased risk for H. pylori infection and to clarify risk factors for H. pylori infection during endoscopy.

METHODS

One hundred twenty-one gastrointestinal endoscopists and endoscopy nurses provided personal information, including their observance of infection-control measures, by means of self-administered questionnaire. One hundred one age-matched healthy individuals undergoing routine physical examinations served as controls. Serum samples from each subject were examined with enzyme-linked immunosorbent assay for the presence of IgG antibodies against H. pylori.

RESULTS

Among younger subjects (< 40 years old), endoscopists and endoscopy nurses had higher seropositive rates than did control subjects (p < 0.05). Among older subjects (> or = 40 years old), the seropositive rate did not differ between endoscopy personnel and control subjects (p = 0.2174). However, among older seropositive subjects, endoscopy personnel had significantly higher antibody titers than did control subjects (p < 0.01). Older seropositive endoscopists performed significantly more examinations per month than did their seronegative colleagues (p < 0.05). Furthermore, younger seropositive endoscopy nurses performed significantly more examinations per month than did seronegative nurses (p < 0.05).

CONCLUSIONS

Gastrointestinal endoscopists and endoscopy nurses in Japan are at high risk for H. pylori infection. The risk of H. pylori infection is correlated with the frequency of endoscopic examinations, especially in older gastrointestinal endoscopists and younger endoscopy nurses.

High seroprevalence of IgG against Helicobacter pylori among endoscopists in Taiwan

A prospective survey to investigate the seroprevalence of IgG against Helicobacter pylori among endoscopists in Taiwan was conducted by analyzing blood samples of 70 study subjects and 64 nonendoscopist physicians with quantitative ELISA. Personal information and the practices of infection control related to gastroscopy examination were obtained by a self-administered questionnaire. Significant differences were detected in the IgG prevalence between study and control subjects (80.0% vs 51.6%; P < 0.05). The serum level of antibody in endoscopists (385.2 +/- 36.1 unit/ml) was significantly higher than that of nonedoscopists (211.8 +/- 33.0 unit/ml; P = 0.018). Endoscopists performing 30 or more sessions of gastroscopy per week had higher seroprevalence than those performing less than 30 sessions (90.9% vs 70.3%; P = 0.0126). In conclusion, endoscopists in Taiwan had a high prevalence of H. pylori infection. The cause might be related to the frequency of gastroscopies performed.

Disposable, sheathed, flexible sigmoidoscopy: a prospective, multicenter, randomized trial. The Disposable Endoscope Study Group

A new fiberoptic sigmoidoscopic system has been developed that utilizes a disposable sheath to cover and protect all working surfaces of the endoscope from contamination. The reusable part of the endoscope has no air, water, or suction/biopsy channels. These are incorporated in the disposable sheath, which is easily removed after use to provide each patient with a contamination-free endoscope. A prospective, randomized, controlled trial was performed to compare the disposable, sheathed, flexible sigmoidoscope with standard sigmoidoscopes. Clinical evaluations of the new sigmoidoscope system were performed at 15 facilities. Visual analog rating scales were used to record evaluations of endoscope performance and reprocessing by endoscopists and reprocessing personnel. The time to perform procedures, depth of insertion, and total instrument downtime were also recorded. One hundred forty-three procedures (70 standard, 73 sheathed) were performed. No significant difference was found for overall depth of insertion (50 versus 48 cm), although fewer sheathed endoscopes reached to 60 cm than did standard endoscopes (51% versus 30%). The sheathed system had a slightly longer mean procedure time than the standard (5.6 versus 6.7 minutes), but a significantly shortened overall downtime (32.8 vs 8.1 minutes). The standard system was preferred by the endoscopists. Reprocessing personnel preferred the disposable system. The disposable sigmoidoscope system has important advantages of decreased instrument turn-around time and potentially increased staff and patient safety, and future models should be improved to meet physicians' concerns.

Endoscope decontamination: automated vs. manual

Automated endoscope washer disinfectors are widely used for the decontamination of flexible endoscopes. They are more effective than manual techniques and reduce the likelihood of skin contact with irritant disinfectants. Suitable machines are those which effectively clean, disinfect and rinse all channels and external surfaces without damaging the instrument. If glutaraldehyde is used, fumes should be removed or contained to protect endoscopy and processing staff. Machines should also be equipped with a self-disinfect facility and the rinse water should be of a suitable microbiological quality for the instruments processed, i.e. bacteria-free (sterile or filtered) water should be used for bronchoscopes and all invasive endoscopes. The choice of machine and cycle will depend on the following: whether a mobile or fixed unit is required; the type of disinfectant used; instrument throughput; and whether or not it is necessary to process more than one endoscope at a time. Purchasers are advised to request independent test reports which substantiate manufacturers' claims.

Prophylactic antibiotic treatment in therapeutic or complicated diagnostic ERCP: results of a randomized controlled clinical study

The present study evaluated the effects of prophylactic administration of cefotaxime in patients undergoing therapeutic or complicated diagnostic ERCP. One hundred patients were randomized to two groups of 50 patients each. Patients in group 1 received an intravenous infusion of 2 g cefotaxime 15 minutes before endoscopy; patients in group 2 did not receive an intravenous antibiotic before ERCP (control group). Blood samples were drawn for bacteriologic cultures before endoscopy and 5, 15, 30, and 120 minutes after beginning the procedure. Bacteremia was detected by blood cultures (15- and 30-minute samples) in 4 patients who did not receive prophylactic antibiotics (Escherichia coli in 2 cases, Peptostreptococcus in 1, and Staphylococcus aureus in 1). Cholangitis or sepsis did not occur after the bacteremic episodes in any of these patients. In 4 other patients who did not receive cefotaxime-all of whom had biliary obstruction-clinical cholangitis or sepsis developed during the 3-day follow-up; ERCP had failed to decompress the biliary system completely in these 4 cases. Blood cultures identified bacteria in 3 of these 4 patients (Pseudomonas aeruginosa in 1, E. coli in 2). Thus, bacteremia or clinical sepsis developed in 8/50 patients (16%) in the control group without antibiotic prophylaxis, whereas no such episode was observed in patients who had received prophylactic treatment (chi 2 = 8.7; p < 0.01). The present results indicate that prophylactic administration of an antibiotic such as cefotaxime can reduce the incidence of bacteremia and sepsis in patients who undergo therapeutic or complicated diagnostic ERCP.(ABSTRACT TRUNCATED AT 250 WORDS)

Standardizing glutaraldehyde use in a regional group of ten major medical centers

The ICPs of 10 Southern California medical centers were able to coordinate efforts to standardize the use of glutaraldehyde for high-level disinfection. In implementing "APIC Guidelines for Selection and Use of Disinfectants," variations in practice similar to those recognized nationally were identified. Through coordinated efforts, the regional ICP group researched and developed a position paper to facilitate standardization of high-level disinfection practice.

Pseudomonas aeruginosa and Enterobacteriaceae bacteremia after biliary endoscopy: an outbreak investigation using DNA macrorestriction analysis

PURPOSE

An outbreak of gram-negative bacteremia in patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) was investigated to determine the sources of infection and to control transmission.

PATIENTS, METHODS, AND RESULTS

The incidence of post-ERCP bacteremia increased from 1.6% (60 of 3,696) procedures to 3.6% (53 of 1,454) procedures (relative risk 2.3, p < 0.0001) after endoscopes were processed in a new automated disinfector. Bacteremia involved nine species of Pseudomonas and Enterobacteriaceae, which were also isolated from processed endoscopes. Seven epidemic strains with highly related genomic macrorestriction profiles each infected 2 or more patients, accounting for 29 (55%) episodes of post-ERCP bacteremia. Strains recovered from endoscopes and from the disinfector were associated with 22 (42%) and 5 (9%) bacteremic episodes respectively. Effective endoscope disinfection was achieved by cleansing and disinfection of a blind channel not processed in the disinfector, additional isopropanol-air flush of all channels, and auto-disinfection of the disinfector. In the following period, the incidence of post-ERCP bacteremia returned to the pre-epidemic rate (1.7%, p = 0.0001).

CONCLUSION

Bacterial genome fingerprinting by macrorestriction analysis enabled delineation of a multi-strain outbreak of post-ERCP bacteremia. Cross-contamination, and to a lesser extent, common-source contamination, appeared related to inadequate disinfection of endoscopes processed in an automated disinfector.

Bactericidal, virucidal, and mycobactericidal activities of reused alkaline glutaraldehyde in an endoscopy unit

Baths with 2% alkaline glutaraldehyde are often reused for 14 days to decontaminate flexible fiberoptic endoscopes (FFEs) between patients, but the effect of such reuse on the disinfectant's activity has not been known. Many busy endoscopy units also disinfect FFEs with contact times shorter than those recommended by the disinfectant manufacturer. We therefore collected samples of the disinfectant over the 14-day reuse period from two manual and one automatic bath used for bronchoscopes and gastroscopes at a local hospital. Control samples were also collected from a manual bath of 2% alkaline glutaraldehyde which did not receive any endoscopes. The germicidal activities of the samples were assessed in a carrier test against a mixture of hepatitis A virus, poliovirus 1 (Sabin), and Pseudomonas aeruginosa; the mixture also contained either Mycobacterium bovis or Mycobacterium gordonae. Bovine serum (5%) was the organic load. The criterion of efficacy was a minimum of a 3-log10-unit reduction in the infectivity titers of the organisms tested. The initial disinfectant concentration in all the baths was nearly 2.25%; it became about 1.8% in the control bath and fell to approximately 1% in the three test baths after 14 days. No protein was detected in the control bath, while its concentration rose gradually in the test baths to a maximum of 1,267 micrograms/ml after 14 days. With a contact time of 10 min at 20 +/- 2 degrees C, all the samples from the control bath were effective against all the test organisms and all the samples from all the test baths were also effective against P. aeruginosa. With a contact time of 10 or 20 min at 20+/-2 degrees C, the virucidal and mycobactericidal activities of the samples from the test baths showed broad-spectrum germicidal activity when the contact time was increased to 45 min and the temperature was raised to 25 degrees C. These findings emphasize the care needed in the disinfection of FFEs, especially in view of the increasing threat of AIDS and the resurgence of tuberculosis.

The mechanics of endoscope disinfection

The decontamination of flexible fibreoptic endoscopes has considerably improved in recent years. This is mainly due to the introduction of instruments with more accessible channels, the use of automated washer disinfectors and a greater awareness of the problems associated with disinfection. Unfortunately the most widely used and effective disinfectant is 2% glutaraldehyde and this is toxic, irritant and sensitizing. With the implementation of Control of Substances Hazardous to Health legislation, strict environmental controls are required to reduce skin contact and vapour inhalation. Alcohol is probably the most suitable alternative disinfectant at present but it is flammable and cannot be used in automated systems. Other agents are either insufficiently effective or corrosive. Autoclavable or heat tolerant rigid endoscopes are now available but flexible endoscopes will not tolerate heat disinfection temperatures.

Chemical disinfection of hepatitis A virus on environmental surfaces

Hepatitis A virus disinfection was assessed on contaminated stainless-steel disks. Ten microliters of fecally suspended hepatitis A virus was deposited on the center of each disk, dried for 20 min, and then covered with 20 microliters of the test product for 1 min. Of the 20 formulations tested, only 2% glutaraldehyde, a quaternary ammonium formulation containing 23% HCl (toilet bowl cleaner), and sodium hypochlorite (greater than 5,000 ppm [greater than 5,000 micrograms/ml] of free chlorine) reduced the virus titer by greater than 99.9%; phenolics, iodine-based products, alcohols, and solutions of acetic, peracetic, citric, and phosphoric acids were unable to do so.