English
ESGE-ESGENA guideline for quality assurance in reprocessing: Microbiological surveillance testing in endoscopy
1. Introduction
2. Risk of infections, and potential problem areas during reprocessing
3. Responsibilities
4. Frequency
5. Sampling for routine tests
5.1. Endoscopes
5.2. Final rinse water in washer-disinfectors
5.3. Water supply
6. Cultures/culturing
6.1. Liquid samples from endoscope channels
6.2. Swabs
6.3. Water samples
6.4. Additional tests
7. Interpretation of results and corrective measures in case of contamination
7.1. Total microbiological count
7.2. Detection of special microorganisms
8. Management of outbreak of infectious agent
9. References
10. Appendix
Microbiological surveillance is an important means for evaluating the outcome quality of reprocessing procedures and is an instrument of regular quality control in gastrointestinal endoscopy, whether endoscopic procedures are performed in hospitals, in private clinics or doctors’ offices. It is an instrument for detecting and redressing weaknesses and mistakes in the reprocessing procedure and for preventing the transmission of infectious agents through endoscopy.
This guideline, from the European Society of Gastrointestinal Endoscopy (ESGE) and the European Society of Gastroenterology and Endoscopy Nurses and Associates (ESGENA), addresses the necessity for microbiological surveillance in endoscopy and provides practical information about testing the quality of the microbiological outcomes of manual and automated reprocessing procedures used in endoscopy.
It is a consensus guideline, prepared in co-operation with endoscopists, microbiologists, hygienists, endoscopy nurses, and representatives from industry.
Aims of this ESGE-ESGENA guideline
These are:
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To support individual endoscopy departments in developing local standards and protocols for regular microbiological surveillance
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To support national societies and official bodies in developing national recommendations and quality assurance programs for hygiene and infection control in gastrointestinal endoscopy
Endoscopic procedures have become an essential tool in the diagnosis and treatment of gastrointestinal diseases, and every patient has the right to be examined and treated without risk of transmission of infectious agents or complications that may result from inadequate reprocessing of endoscopes and endoscopic accessories[1].
Since the late 1970s there have been sporadic reports of nosocomial infections linked to endoscopic procedures. Bacterial infections have been acquired during endoscopy, caused for example bySalmonella spp.,Helicobacter pylori andPseudomonas spp.[2][3][4][5][6]. Viral diseases such as hepatitis B and C have also been transmitted during endoscopy[7][8]. The majority of documented cases were caused by non-compliance with national and international reprocessing guidelines[2][3][4][5][6][7][8].
Manual cleaning including brushing is the first and most important step in reprocessing flexible endoscopes[1][9][10], regardless of whether an automated system is used. Non-cleaned or insufficiently cleaned endoscope channels promote the formation of microbial plaques and biofilms. Organic material which is not removed by manual brushing can additionally be fixed by aldehydes and promote the growth of organisms. Manual cleaning must include all accessible endoscope channels, all valve ports, the outer surface, and parts that are difficult to access such as the bridge elevator. Therefore, thorough cleaning is a prerequisite for adequate disinfection, regardless of whether the endoscope is reprocessed manually or in an automatic washer-disinfector.
In addition to the endoscopes themselves, water bottles can be a source of endoscope contamination. This can be caused by inadequate cleaning of water bottles, lack of sterilization or use of tap water instead of sterile water[11]. Therefore, testing of water bottles should be part of regular quality control.
As the design of endoscopes varies depending on the manufacturer, it is essential that staff is familiar with the design and construction of all the equipment in order to ensure safe and adequate cleaning and disinfection.
[Table 1] presents a summary of areas of weakness and deficiencies with regard to endoscope reprocessing.
Table 1 Weaknesses and deficiencies in endoscope reprocessing (modified from reference[12])
| a. Inadequate reprocessing of endoscopes and accessories |
| b. Inadequate transport and storage of endoscopes |
| c. Contaminated or defective washer-disinfector |
| d. Design limitations and damaged endoscopes |
| e. Contaminated water in the endoscopy unit |
A quality assurance program with regular microbiological surveillance should be established for endoscopy rooms, whether endoscopy is carried out in hospitals, private clinics, or doctors’ offices.
The clinical service providers have a duty of care to provide hygiene supervision and to carry out microbiological surveillance. Furthermore, every professional also has a duty of care to comply with the relevant national recommendations and regulations.
The collection, culturing, and interpretation of test results should be performed in close co-operation with the endoscopists, endoscopy nurses, hygienists and appropriate microbiology personnel/microbiologists. All test details (including test media, method of collecting samples, culture, and interpretation) should be discussed with the relevant microbiological authorities prior to testing.
Depending on the reprocessing procedure (manual or automated), routine quality assurance of the whole endoscope reprocessing system must be established. Routine testing can cover periodic microbiological surveillance of endoscopes, washer-disinfectors, accessories, and the water supply used in endoscopy.
National guidelines and laws on hygiene and infection control in gastrointestinal endoscopy vary from country to country[9][10]. Consequently the frequency of microbiological surveillance and recommended test procedures differs across Europe (see Appendix). This guideline will therefore need to be modified locally in compliance with the appropriate national regulations.
As a point of reference, the ESGE-ESGENA guideline committee recommends routine testing at intervals no longer than 3 months.
Endoscopes. Depending on the number of endoscopes in use, it may be impractical to test each endoscope at each occasion. Therefore a sample of each type/series should be tested at each sampling session in rotation, making sure that at the end of the year each endoscope has been sampled at least once.
Water supply. Microbiological surveillance of the final rinse water used in endoscopy should be carried out on the same day as the microbiological surveillance of the endoscopes, in order to assure the testing of the complete reprocessing cycle.
Washer-disinfectors. In the case of automated endoscope reprocessing, validation of the whole procedure is necessary to ensure that it complies with the requirements of the European Standard, prEN ISO 15 883 parts 1, 4 and 5[13]. TheESGE-ESGENA guideline for process validation and for routine testing for endoscope reprocessing in washer-disinfectors should be considered in this regard[14].
The microbiologists should record the data and make a simple trend analysis to see if any contamination detected increased or decreased between tests in order to identify any changing circumstances before a potential outbreak.
5.1. Endoscopes
Microbiological testing of endoscopes should cover:
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all channels
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the outer surfaces, and
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the connected water bottle.
A sampling plan for each endoscope type has to be established, that takes into account the critical parts of each type.
Sterile saline 0.9 % is the most popular test solution. Depending on requirements, a dose of neutralizer can be added to the saline solution (or into the sterile sampling container) in order to neutralize any traces of chemicals which may limit detection of microorganisms. Reports onin vitro efficacy tests of the disinfectant used may serve as indicators for the choice of an appropriate neutralizer.
To avoid contamination from the environment, the collection of samples must be done under aseptic conditions.
Method of sampling. Standard testing of the endoscope includes collection of:
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liquid samples from endoscope channels,
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swabs from outer surfaces, and
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liquid samples from water bottles.
a. Liquid samples from endoscope channels. Flush the appropriate channels with 20 ml sterile saline and collect the liquid in a sterile container (see[Table 2]).
Table 2 Sampling methods for testing the quality of reprocessing of endoscopes
Test area/material | Test method | Standard |
|---|---|---|
| Each endoscope channel | Flushing or rinsing of: | - Fill a sterile syringe with 20 ml sterile saline |
| Outer surfaces | Swabs from e. g.: | - Use sterile swabs, moistened with sterile saline with or without appropriate neutralizer |
| Water bottle | Liquid sample | - Water bottle ready for use should be tested |
| Final rinse water | Water sample | - Use a sterile syringe |
Note:
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Because of the complex construction of endoscope channels, each channel should be tested separately.
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Adequate connectors should be used to ensure the complete and separate flushing of each channel.
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The endoscope manufacturer should give clear instructions on how to connect and test each channel.
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Because of its small lumen, the elevator channel of duodenoscopes should be tested by flushing with 5 ml sterile saline with or without an appropriate neutralizer.
b. Swabs from the outer surfaces of the endoscope. These swabs are taken to test the adequacy of cleaning and disinfection. The method is described in[Table 2].
c. Liquid samples from water bottles. Water samples should be taken from water bottles at the end of the defined application period (see[Table 2]).
5.2. Final rinse water of washer-disinfectors
Depending on the design of the washer-disinfector, the options for collecting samples may vary. Irrespective of the type of washer-disinfector, the complete reprocessing cycle should be tested. Manufacturers should provide advice regarding appropriate means of microbiological sampling. A sample of 2 × 100 ml should be taken from the final rinse water.
5.3. Water supply
Take water samples according to national recommendations for testing of tap water.
The samples should be processed shortly after collection. If any delay is likely, the samples should be refrigerated (e. g. for transportation).
6.1. Liquid samples from endoscope channels
Total microbiological count. Take 1 ml of the sample and place on an appropriate number of plates (depending on plate size) of a complete medium (e. g. Tryptic Soy Agar [TSA]). Incubate for 48 h at 30 °C.
Depending on the required detection limit, another 10 ml of the same sample can be filtered (pore diameter not greater than 0.45 µm). The filter is incubated on an agar plate containing a complete medium (e. g. TSA) at 30 °C for 48 h.
Detection of special microorganisms.
Enterobacteriaceae,Pseudomonas aeruginosa and staphylococci should be tested as indicator organisms. We would recommend that not only the final rinse water but also the endoscopes should be tested for atypical mycobacteria. This would ensure that the whole system is tested according to prEN ISO 15 883 - 4.
Add the same volume of double-concentrated Tryptic Soy Broth (TSB) to the rest of the sample and incubate it at 37 °C for 48 h. Double concentrated MADC broth and incubation at 37 °C for 21 days should be used if a test for mycobacteria is deemed appropriate. Streak out on selective agar plates and incubate for an appropriate time and temperature according to the manufacturer’s instructions, for example, using:
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Violet Red Bile Dextrose (VRBD) agar as a selective medium for detection of Enterobacteriaceae
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Cetrimid agar for detection ofPseudomonas aeruginosa
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Baird-Parker agar for detection of staphylococci
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Middlebrook agar for detection of mycobacteria
Further identification tests (e. g. commercially available biochemical test systems for bacteria or acid-fast stain for mycobacteria) may be necessary to confirm the presence of certain groups or species of bacteria.
6.2. Swabs
Extract the swab in 10 ml of TSB plus neutralizer, using a vortex.
Detection of special microorganisms. Incubate the 10 ml volume at 37 °C in an incubator for 48 h. Streak out on selective agar plates and incubate for an appropriate time and temperature, according to the manufacturer’s instructions (see section 6.1.)
6.3. Water samples (from water bottle + final rinse water)
According to the European Standard, prEN ISO 15 883 - 4 the final rinse water should be free ofPseudomonas aeruginosa, atypical mycobacteria andLegionellae spp.
The aerobic total microbial count is determined by filtration (0.45 µm pore size) of 10 ml and 100 ml water samples. The sample is incubated at 30 ± 2 °C on R2A medium or another appropriate low nutrient medium for 5 days. The colonies are counted, and the type of microbe is determined by subculture on appropriate selective media and/or standard identification techniques (e. g. commercially available biochemical test systems) are used.
For the detection of mycobacteria, Middlebrook 7H10 agar should be used and incubated at 37 °C for up to 21 days.
The methodology of the International Standard ISO 11 731 can be used for the detection ofLegionella spp.
For higher sensitivity in the detection of indicator organisms, an enrichment technique can be used, as follows. A 100 ml water sample is added to 100 ml double strength TSB and incubated at 37 °C for 48 h. The culture is then streaked onto selective media (see section 6.1) for identification of any grown organisms. For the detection of atypical mycobacteria, double strength MADC broth (at 37 °C for 21 days) and subculture on Middlebrook 7H10 agar (at 37 °C for 21 days) should be used.
6.4. Additional tests
If clinical or epidemiological data suggest the transmission of infectious agents, in addition to the routine sampling, the test methods should focus on the suspicious organism (see section 8, Management of outbreak of infectious agent).
A variety of bacteria and viruses have been associated with endoscopy-related transmission of infectious agents[2][3][4][5][6][7][8]. The detection of viruses is complex, time-consuming and expensive, especially that of intact, infective viruses. Therefore routine microbiological surveillance does not include viruses.
In the case of regular microbiological surveillance, it is not necessary to test for all possible bacteria. A number of organisms can be used as indicators of weaknesses or mistakes in the reprocessing procedure. An overview is given in[Table 3].
Table 3 Indicator organisms for quality control
Organisms identified in microbiological tests | Indication of origin | Troubleshooting |
|---|---|---|
| Escherichia coli, enterococci and Enterobacteriaceae | A: Insufficient cleaning and/or disinfection procedures, e. g.: | A: Review whole reprocessing cycle with special emphasis on manual cleaning |
| B: Mechanical or electronic defects of washer-disinfector, e. g.: | B: Initiate full maintenance of washer-disinfector | |
| Pseudomonas aeruginosa and other gram-negative nonfermenters | A: | A: Review water supply systems and procedures: |
| B: Insufficient drying of endoscopes before storage | B: Review drying procedures before storage, and ventilation of storage facilities | |
| Staphyloccus aureus,Staphylococcus epidermidis | Recontamination of endoscopes due to: | Review of hygiene arrangement for storage, transport and of manual handling |
| Contamination from sampling | Repeat sampling | |
| Atypical mycobacteria | Contamination of washer-disinfector and water system | Review water supply systems and procedures: |
7.1. Total microbiological count
a. Liquid samples from endoscope channels. The maximal total count should be < 20 cfu/channel. It should be calculated taking into account the amount of saline used to rinse the channel. Indicator organisms should not be found at any time.
b. Swabs. Cultures taken from swabs should be focused on the growth of indicator organisms (see section 7.2. and[Table 3]). Quantification of microorganisms is not recommended.
c. Water samples. The maximum total count should be should be < 10/100 cfu/ml. Indicator organisms should not be found at any time.
7.2. Detection of special microorganisms
A criterion for acceptability is theabsence of growth of indicator organisms (see[Table 3]).
In the case of manual reprocessing, the endoscopes and water used in endoscopy rooms must be tested ([Figure 1]).
In the case of automated reprocessing, the endoscopes, washer-disinfector, and the water used in endoscopy must be tested at the same time, in order to identify the cause of infection ([Figure 2]).
If any contamination is found, it is the responsibility of the clinical service provider to take the suspect piece of equipment out of service (e. g. endoscopes, washer-disinfector, accessories, etc), until corrective actions have been taken and satisfactory results have been achieved[14].
Table 4 National variations in reprocessing of endoscopic equipment and provision of guidelines
Country | Manual reprocessing of endoscopes | Automated reprocessing of endoscopes | National guidelines on endoscopes and accessories | National guideline on microbiological surveillance |
|---|---|---|---|---|
| Austria | X | X | X | |
| Belgium | X | X | X | |
| Croatia | X | X | ||
| Czech Republic | X | |||
| Denmark | X | |||
| Finland | X | X | ||
| France | X | X | X | |
| Germany | X | X | X | |
| Iceland | X | |||
| Italy | X | X | X | |
| Jordan | X | X | ||
| Luxembourg | X | |||
| Monaco | X | X | X | |
| Netherlands | X | X | ||
| Norway | X | |||
| Slovenia | X | X | X | |
| Spain | X | |||
| Sweden | X | X | X | |
| Switzerland | X | X | ||
| UK | X | X | X | |
| Total | 4 | 18 | 13 | 8 |
Table 5 National variations in testing intervals for routine microbiological surveillance
Country | Interval between tests, months (except where indicated) | ||
|---|---|---|---|
Endoscopes | Automatic washer-disinfectors | Water | |
| Austria | 12 | 12 | NA |
| Croatia | 3 | 3 | 3 |
| Denmark | 1 | 6 | 0 |
| France | 12 | 3 | 1 |
| Germany | 3 | 3 | 3 |
| Italy | 6 | 6 | 12 |
| Monaco | 1 | 1 | 1 |
| Slovenia | Individual tests | Individual tests | 6 |
| Spain | 3 | No | No |
| Sweden | 3 | 3 | No |
| Switzerland | 3 | NA | NA |
| UK | No tests of endoscopes | According to manufacturers’ recommendations | Once a week |
| NA, = Not announced | |||
A survey was performed in July 2006 in the ESGE and ESGENA membership countries, and there were replies from 20 countries. In the majority of countries endoscopes are reprocessed in automated systems (18/20). Among the 20 countries, 13 have national guidelines on reprocessing of endoscopes and accessories, while national guidelines on microbiological surveillance are available in eight of the 20 (see Table[4]). Microbiological testing varies greatly between countries in 12 of the 20. Many countries recommend testing every 3 months (see Table[5]).
9. References
ESGE-ESGENA Guideline Committee. Guidelines on cleaning and disinfection in gastrointestinal endoscopy - update 1999. Endoscopy 2000; 32: 77-83
Spach DH, Silverstein FE, Stamm WE. Transmission of infection by gastrointestinal endoscopy. Ann Intern Med 1993; 118: 117-128
Ayliffe GA Nosocomial infections associated with endoscopy. , In: Mayhall CG (ed). Hospital epidemiology and infection control. Baltimore: Williams & Wilkins; 1995: 680-693
Cowen AE. The clinical risks of infections associated with endoscopy. Can J Gastroenterol 2001; 15: 321-331
Langenberg W, Rauws EA, Oudbier JH, Tytgat GN. Patient to patient transmission of Campylobacter pylori by fiberoptic gastroduodenoscopy and biopsy. J Infect Dis 1990; 161: 507-511
Moayyedi P, Lynch D, Axon A. Pseudomonas and endoscopy. Endoscopy 1994; 26: 554-558
Bronowicki JP, Vernard V, Botte C. et al. Patient-to-patient transmission of hepatitis C virus during colonoscopy. N Engl J Med 1997; 337: 237-240
Birnie GG, Quigley EM, Clements GB. et al. Endoscopic transmission of hepatitis B virus. Gut 1983; 24: 171-174
Rey JF, Kruse A. Cleaning and disinfection in Europe according to the endoscopic societies’ guidelines. Endoscopy 2003; 35: 878-881
Leiss O, Beilenhoff U, Bader L. et al. Reprocessing of flexible endoscopes and endoscopic accessories - an international comparison of guidelines. Z Gastroenterol 2002; 40: 531-542
Bader L, Blumenstock G, Birkner B. HYGEA (Hygiene in der Gastroenterologie-Endoskop-Aufbereitung): Studie zur Qualität der Aufbereitung von flexiblen Endoskopen in Klinik und Praxis [HYGEA (Hygiene in gastroenterology - endoscope reprocessing): Study on quality of reprocessing flexible endoscopes in hospitals and in the practice setting]. Z Gastroenterol 2002; 40: 157-170
RKI (Robert Koch Institut). Empfehlungen der Kommission für Krankenhaushygiene und Infektionsprävention beim Robert-Koch-Insitut zu den Anforderungen an die Hygiene bei der Aufbereitung flexibler Endoskope und endoskopischen Zusatzinstrumentariums. Bundesgesundheitsblatt 2002; 45: 395-411
prEN ISO 15 883.
ESGE-ESGENA-Guideline Commitee. ESGE-ESGENA guideline for process validation and for routine tests for reprocessing endoscopes in washer disinfectors, according to prEN ISO 15883, parts 1, 4 and 5. Endoscopy; 2007; 39: 85-94
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