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Copyright © 2004 WA Rutala
Endoscope Reprocessing:
Current Status of Disinfection Recommendations
William A. Rutala, Ph.D., M.P.H.
University of North Carolina (UNC) Health Care
System and UNC at Chapel Hill

Endoscope Reprocessing
Lecture Goals
 Background
 Infections related to endoscopy
 Reprocessing of endoscopes and accessories
 Cleaning
 High-level disinfection/sterilization
 Automated endoscope reprocessing
 Quality control

GI ENDOSCOPES
 Widely used diagnostic and therapeutic procedure
 Endoscope contamination during use (109 in/105 out)
 Semicritical items require high-level disinfection minimally
 Inappropriate cleaning and disinfection has lead to cross-
transmission
 In the inanimate environment, although the incidence remains very
low, endoscopes represent a risk of disease transmission

TRANSMISSION OF INFECTION
 Gastrointestinal endoscopy
 >300 infections transmitted
 70% agents Salmonella sp. and P. aeruginosa
 Clinical spectrum ranged from colonization to death (~4%)
 Bronchoscopy
 90 infections transmitted
 M. tuberculosis, atypical Mycobacteria, P. aeruginosa
Spach DH et al Ann Intern Med 1993: 118:117-128 and Weber DJ, Rutala WA Gastroint Dis 2002

Nosocomial Infections via GI Endoscopes
 Observations
 Number of reported infections is small, suggesting a very low
incidence
 Endemic transmission may go unrecognized (e.g.inadequate
surveillance, low frequency, asymptomatic infections)
Spach DH. Ann Int Med 1993;118:117 and Weber DJ, Rutala, WA. Gastroint Dis 2002

Nosocomial Infections via GI Endoscopes
 Infections traced to deficient practices
 Inadequate cleaning (clean all channels)
 Inappropriate/ineffective disinfection (time exposure, perfuse
channels, test concentration, ineffective disinfectant,
inappropriate disinfectant)
 Failure to follow recommended disinfection practices (tapwater
rinse)
 Flaws is design of endoscopes or AERs

Endoscope Reprocessing: Current Status of
Cleaning and Disinfection
 Guidelines
 Multi-Society Guideline, 11 professional organizations, 2003
 Society of Gastroenterology Nurses and Associates, 2000
 European Society of Gastrointestinal Endoscopy, 2000
 British Society of Gastroenterology Endoscopy, 1998
 Gastroenterological Society of Australia, 1999
 Gastroenterological Nurses Society of Australia, 1999
 American Society for Gastrointestinal Endoscopy, 1996
 Association for Professional in Infection Control and Epidemiology, 2000
 Centers for Disease Control and Prevention, 2004 (in press)

Endoscope Reprocessing, Worldwide
 Worldwide, endoscopy reprocessing varies greatly
 India, of 133 endoscopy centers, only 1/3 performed even a
minimum disinfection (1% glut for 2 min)
 Brazil, “a high standard …occur only exceptionally”
 Western Europe, >30% did not adequately disinfect
 Japan, found “exceedingly poor” disinfection protocols
 US, 25% of endoscopes revealed >100,000 bacteria
Schembre DB. Gastroint Endoscopy 2000;10:215

Endoscopes

ENDOSCOPE DISINFECTION
 CLEAN-mechanically cleaned with water and enzymatic
cleaner
 HLD/STERILIZE-immerse scope and perfuse
HLD/sterilant through all channels for exposure time
 RINSE-scope and channels rinsed with sterile water,
filtered water, or tap water followed by alcohol
 DRY-use forced air to dry insertion tube and channels
 STORE-prevent recontamination

ENDOSCOPE REPROCESSING
 Source of contamination for infections (36 outbreaks)
transmitted by GI endoscopes from 1974-2001:
 Cleaning-3 (12%)
 Disinfection-19 (73%)
 Rinse, Dry, Store-3 (12%)
 Etiology unknown-11

 Cleaning (results in dramatic decrease in bioburden, 4-5
log10 reduction)
 No brushing biopsy channel. (Schousboe M. NZ Med J
1980;92:275)
 No precleaning before AER. (Hawkey PM. J Hosp Inf
1981;2:373)
 Biopsy-suction channel not cleaned with a brush.
(Bronowicki JP. NEJM 1997;337:237)

Bacterial Bioburden Associated with Endoscopes
Gastroscope, log10
CFU
Colonoscope, log10
CFU
After procedure 6.7 8.5 Gastro Nursing 1998;22:63
6.8 8.5 Am J Inf Cont 1999;27:392
9.8 Gastro Endosc 1997;48:137
After cleaning 2.0 2.3
4.8 4.3
5.1

Viral Bioburden from Endoscopes Used with AIDS Patients
Hanson et al. Lancet 1989;2:86; Hanson et al. Thorax 1991;46:410
Dirty Cleaned Disinfected
Gastroscopes
HIV (PCR) 7/20 0/20 0/20
HBsAg 1/20 0/20 0/7
Bronchoscopes
HIV (cDNA) 7/7 0/7 0/7
HBsAg 1/10 0/10 0/10

 Precleaning
 After removal from patient, wipe the insertion tube with a wet
cloth and alternate suctioning the enzymatic cleaner and air
through the biopsy/suction channel until solution clean. The air-
water channel is flushed or blown out per instructions.
 Transport the endoscope to the reprocessing area.
 Enyzmatic cleaner should be prepared per instructions. Some
data suggest enzymes are more effective cleaners than
detergents. Enyzmatic cleaners must be changed after use.

 Cleaning
 Immerse in a compatible low-sudsing, enzymatic cleaner
 Wash all debris from exterior by brushing and wiping
 Remove all removal parts of the endoscope and clean each
reusable part separately
 After exterior cleaning, brush accessible channels with
appropriate-sized cleaning brush (bristles contact all surfaces)

 Cleaning (continued)
 After each passage, rinse the brush, remove debris before reinserting.
Continue until no visible debris on brush.
 Attach cleaning adapters for each channel per manufacturer’s
instructions and flush with enzymatic cleaner to remove debris.
 After cleaning is complete, rinse the endoscope with clean water.
 Purge water from channels using forced air. Dry exterior of the endoscope
with a soft, lint-free cloth.

 CLEAN-mechanically cleaned with water and enzymatic
detergent

 Source of contaminations for infections (36 outbreaks)
transmitted by GI endoscopes from 1974-2001:
 Cleaning-3 (12%)
 Disinfection-19 (73%)
 Rinse, Dry, Store-3 (12%)
 Etiology unknown-11

Unacceptable Disinfectants for HLD
 Benzalkonium chloride
 Iodophor
 Hexachlorophene
 Alcohol
 Chlorhexidine gluconate
 Cetrimide
 Quaternary ammonium compounds
 Glutaraldehyde (0.13%) with phenol

 Inappropriate disinfectants
 Benzalkonium chloride (Greene WH. Gastroenterol 1974;67:912)
 70% alcohol (Elson CO. Gastroenterol 1975;69:507)
 QUAT (Tuffnell PG. Canad J Publ Health 1976;67:141)
 Hexachlorophene (Dean AG. Lancet 1977;2:134)
 Hexachlorophene (Beecham HJ. JAMA 1979;1013)
 70% alcohol (Parker HW. Gastro Endos 1979;25;102)
 Povidone-iodine (Low DE. Arch Intern Med 1980;1076)
 Cetrimonium bromide. (Schliessler KH. Lancet 1980;2:1246)

 Inappropriate disinfectants
 3% hexachlorophene. (Schousboe M. NZ Med J 1980;92:275)
 0.5% CHG in alcohol, 0.015% CHG and 0.15% cetrimide; 87 s
exposure to 2% glut. (Hawkey PM. J Hosp Inf 1981;2:373)
 1% Savlon (cetrimide and CHG).(O’Connor BH. Lancet 1982;2:864)
 0.0075% iodophor. (Dwyer DM. Gastroint Endosc 1987;33:84)
 0.13% glut with phenol. (Classen DC. Am J Med 1988;84:590)
 70% ethanol for 3 min. (Langenberg W. J Inf Dis 1990;161:507)

 Inappropriate disinfection
 Air/water channel not exposed to glut. (Birnie GG. Gut
1983;24:171)
 Air/water channel not exposed to glut. (Cryan EMJ. J Hosp Inf
1984;5:371)
 No glut (water only) between patients. (Earnshaw JJ. J Hosp Inf
1985;6:95)

High Level Disinfection of
“Semicritical Objects”
Exposure Time > 12 m-30m, 20oC
Germicide Concentration_____
Glutaraldehyde > 2.0%
Ortho-phthalaldehyde (12 m) 0.55%
Hydrogen peroxide* 7.5%
Hydrogen peroxide and peracetic acid* 1.0%/0.08%
Hydrogen peroxide and peracetic acid* 7.5%/0.23%
Hypochlorite (free chlorine)* 650-675 ppm
Glut and phenol/phenate** 1.21%/1.93%___
*May cause cosmetic and functional damage; **efficacy not verified

New FDA-Cleared Sterilants
 “Old”
 > 2% Glut, 7.5% HP, 1.0% HP and 0.08% PA
 New
 1.21% glut and 1.93% phenol/phenate (HLD-20 m at 25oC)
 0.55% ortho-phthalaldehyde (HLD-12 m)
 7.35% HP and 0.23% PA (HLD-15 m)
 2.5% Glut (HLD-5 m at 35oC)
 Hypochlorite (650-675ppm free chlorine)
 Ensure antimicrobial activity and material compatibility

Glutaraldehyde
 Advantages
 Numerous use studies published
 Relatively inexpensive
 Excellent materials compatibility
 Disadvantages
 Respiratory irritation from vapor
 Pungent and irritating odor
 Relatively slow mycobactericidal activity
 Coagulate blood and fix tissues to surfaces
 Allergic contact dermatitis

Ortho-phthalaldehyde
Advantages
 Fast acting HLD
 No activation
 Excellent materials compatibility
 Not a known irritant to eyes and
nasal passages
 Weak odor
 No ACGIH or OSHA limit
Disadvantages
 Stains protein gray
 Cost ($30/gal); but lower
reprocessing costs-soak time,
devices per gal
 Slow sporicidal activity
 Hypersensitivity in some patients
with a history of bladder cancer

Ortho-phthalaldehyde (OPA)
New Contraindications for OPA
 Repeated exposure to OPA, following manual reprocessing of urological
instruments, may have resulted in hypersensitivity in some patients with a
history of bladder cancer undergoing repeated cystoscopy.
 Out of approximately 1 million urological procedures, there have been
reports of 24 patients who have experience ‘anaphylaxis-like’ reactions
after repeated cystoscopy (typically after 4-9 treatments).
 Risk control measures: residues of OPA minimized; and contraindicated for
reprocessing of urological instruments used on patients with history of
bladder cancer.

Minimum Effective Concentration (MEC)
High Level Disinfectant (HLD)
 Dilution of HLD occurs during use
 Test strips are available for monitoring MEC
 For example, test strips for glutaraldehyde monitor 1.5%
 Test strip not used to extend the use-life beyond the
expiration date (date test strips when opened)
 Testing frequency based on how frequently the solutions
are used (used daily, test at least daily)
 Record results

 CLEAN-mechanically cleaned with water and
enzymatic detergent
filtered water, or tap water followed by alcohol.
Inadequate rinsing of HLD has caused colitis.

 Rinse, Dry, Store
 Irrigating water bottle. (Doherty DE. Dig Dis Sci
1982;27:169)
 Inadequate drying (no alcohol). (Allen JI. Gastroenterol
1987;92:759)
 Inadequate drying (no alcohol). (Classen DC. Am J Med
1988;84:590)

enzymatic detergent
 DRY-purge channels with air, flush with alcohol (assists
drying), purge channels with air, dry the exterior

enzymatic detergent
 STORE-prevent recontamination (e.g., hang the
endoscope vertically in a cabinet or clean area)

Nosocomial Outbreaks via GI Endoscopes
Infections Associated with Accessories
 Infections associated with biopsy forceps
 Contaminated biopsy forceps. (Dwyer DM. Gastroint Endosc 1987;33:84)
 Contaminated biopsy forceps (no cleaning between cases). Graham DY.
Am J Gastroenterol 1988;83:974)
 Biopsy forceps not sterilized (glut exposed,? time) Bronowicki JP. NEJM
1997;334:237)
 Reusable endoscopic accessories that break the mucosal barrier
should be mechanically cleaned and sterilized between patients

Automated Endoscope Reprocessors (AERs)
 Advantages: automate and standardize reprocessing steps,
reduce personnel exposure to chemicals, filtered tap water
 Disadvantages: failure of AERs linked to outbreaks, does not
eliminate precleaning, does not monitor HLD concentration
 Problems: incompatible AER (side-viewing duodenoscope); biofilm
buildup; contaminated AER; inadequate channel connectors
 MMWR 1999;48:557. Used wrong set-up or connector
 Must ensure exposure of internal surfaces with HLD/sterilant

Disinfection of Emerging Pathogens

Disinfection and Sterilization of
Emerging Pathogens
 Hepatitis C virus
 Clostridium difficile
 Cryptosporidium
 Helicobacter pylori
 E.coli 0157:H7
 SARS coronavirus
 Noroviruses
 Antibiotic-resistant microbes (MDR-TB, VRE, MRSA)
 Creutzfeldt-Jakob disease (no brain, eye, spinal cord contact)

Disinfection and Sterilization of
Emerging Pathogens
Standard disinfection and sterilization procedures
for patient care equipment are adequate to sterilize
or disinfect instruments or devices contaminated
with blood and other body fluids from persons
infected with emerging pathogens

ENDOSCOPE SAFETY
Quality Control
 Ensure protocols equivalent to guidelines from
professional organizations (APIC, SGNA, ASGE)
 Are the staff who reprocess the endoscope specifically
trained in that job?
 Are the staff competency tested at least annually?
 Conduct IC rounds to ensure compliance with policy
 Consider microbiologic sampling of the endoscope

Conclusions
 Endoscopes represent a nosocomial hazard
 Proper cleaning and disinfection will prevent nosocomial
transmission
 Current guidelines should be strictly followed
 Compliance must be monitored
 Safety and efficacy of new technologies must be validated

Thank you

References
 Rutala WA, Weber DJ. Disinfection of endoscopes: Review of new chemical
sterilants for high-level disinfection. Infect Control Hosp Epidemiol
1999;20:69-76.
 Nelson DB, Jarvis WR, Rutala WA, et al. Multi-society guideline for
reprocessing flexible gastrointestinal endoscopes. AJIC 2003;31:309-315.
 Posters: www.olympusamerica.com/msg_section/msg_Reprocessing.asp
 Questions/Slides: www.disinfectionandsterilization.org (WA Rutala)
 Weber DJ, Rutala WA, DiMarino AJ. Prevention of infection following
gastrointestinal endoscopy. In DiMarino AJ. Gastro Dis. 2002;87-107
 Rutala WA, Weber DJ. Reprocessing endoscopes: United States
perspective. J Hosp Infect 2004;56:S27-S39.

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