Effectiveness of a manual disinfection procedure in eliminating hepatitis C virus from experimentally contaminated endoscopes

The Effectiveness of Immersion Disinfection for Flexible Fiberoptic Laryngoscopes

OBJECTIVE: We sought to determine whether highlevel disinfection renders fiberoptic laryngoscopes free of nonviral infectious microorganisms.

METHODS: Six flexible fiberoptic laryngoscopes in heavy use were subjected to surveillance cultures at the beginning, middle, and end of the clinical workday after high-level disinfection to determine if microorganisms could be recovered. Control cultures were obtained by direct contamination of the endoscope with saliva. The rate of microorganism recovery from the endoscopes after high-level disinfection was determined and compared with control specimens.

RESULTS: Among a total of 48 cultures submitted from in use but disinfected fiberoptic laryngoscopes, 1 positive culture (positive rate, 2.1%) for mold species was recovered. No positive bacterial cultures occurred. Eleven of 11 (100%) control cultures were positive for bacterial species ( P < 0.001). The confidence interval for the risk of microorganism contamination of a disinfected laryngoscope ranged from 0.11% to 11.6%.

CONCLUSION: High-level disinfection provides a reasonably effective method of reducing bacterial and fungal contamination of flexible fiberoptic laryngoscopes. Appropriate surveillance technique should be used in each clinical setting with flexible fiberoptic scopes to ensure adequate disinfection effectiveness. (Otolaryngol Head Neck Surg 2004; 130:681-5.)

Results from a Large-Scale Epidemiologic Look-Back Investigation of Improperly Reprocessed Endoscopy Equipment

Objective.

To determine whether improper high-level disinfection practices during endoscopy procedures resulted in bloodborne viral infection transmission.

Design.

Retrospective cohort study.

Setting.

Four Veterans Affairs medical centers (VAMCs).

Patients.

Veterans who underwent colonoscopy and laryngoscopy (ear, nose, and throat [ENT]) procedures from 2003 to 2009.

Methods.

Patients were identified through electronic health record searches and serotested for human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV). Newly discovered case patients were linked to a potential source with known identical infection, whose procedure occurred no more than 1 day prior to the case patient's procedure. Viral genetic testing was performed for case/proximate pairs to determine relatedness.

Results.

Of 10,737 veterans who underwent endoscopy at 4 VAMCs, 9,879 patients agreed to viral testing. Of these, 90 patients were newly diagnosed with 1 or more viral bloodborne pathogens (BBPs). There were no case/proximate pairings found for patients with either HIV or HBV; 24 HCV case/proximate pairings were found, of which 7 case patients and 8 proximate patients had sufficient viral load for further genetic testing. Only 2 of these cases, both of whom underwent laryngoscopy, and their 4 proximates agreed to further testing. None of the 4 remaining proximate patients who underwent colonoscopy agreed to further testing. Mean genetic distance between the 2 case patients and 4 proximate patients ranged from 13.5% to 19.1%.

Conclusions.

Our investigation revealed that exposure to improperly reprocessed ENT endoscopes did not result in viral transmission in those patients who had viral genetic analysis performed. Any potential transmission of BBPs from colonoscopy remains unknown.

Results from a Large-Scale Epidemiologic Look-Back Investigation of Improperly Reprocessed Endoscopy Equipment

Objective.

To determine whether improper high-level disinfection practices during endoscopy procedures resulted in bloodborne viral infection transmission.

Design.

Retrospective cohort study.

Setting.

Four Veterans Affairs medical centers (VAMCs).

Patients.

Veterans who underwent colonoscopy and laryngoscopy (ear, nose, and throat [ENT]) procedures from 2003 to 2009.

Methods.

Patients were identified through electronic health record searches and serotested for human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV). Newly discovered case patients were linked to a potential source with known identical infection, whose procedure occurred no more than 1 day prior to the case patient's procedure. Viral genetic testing was performed for case/proximate pairs to determine relatedness.

Results.

Of 10,737 veterans who underwent endoscopy at 4 VAMCs, 9,879 patients agreed to viral testing. Of these, 90 patients were newly diagnosed with 1 or more viral bloodborne pathogens (BBPs). There were no case/proximate pairings found for patients with either HIV or HBV; 24 HCV case/proximate pairings were found, of which 7 case patients and 8 proximate patients had sufficient viral load for further genetic testing. Only 2 of these cases, both of whom underwent laryngoscopy, and their 4 proximates agreed to further testing. None of the 4 remaining proximate patients who underwent colonoscopy agreed to further testing. Mean genetic distance between the 2 case patients and 4 proximate patients ranged from 13.5% to 19.1%.

Conclusions.

Our investigation revealed that exposure to improperly reprocessed ENT endoscopes did not result in viral transmission in those patients who had viral genetic analysis performed. Any potential transmission of BBPs from colonoscopy remains unknown.

Epidemiology of hepatitis C in Europe

The advent of potent and safe direct-acting antivirals against the hepatitis C virus has the potential of fulfilling the dream of eliminating this infection and its impact on global public health. However, even if effective drugs are at hand, most patients remain unaware of their infection, which may be recognized only in late stages when dire complications have occurred. Europe is not spared by this scourge, with its estimated 19,000,000 persons infected, and knowledge of the epidemiology of HCV and its drivers is a critical tool in fighting this virus. A thorough review is provided on the extent of the HCV epidemic across Europe, with a discussion of the most important subgroups affected, and of the risk factors of infection, both traditional and new.

Is peracetic acid suitable for the cleaning step of reprocessing flexible endoscopes?

The bioburden (blood, protein, pathogens and biofilm) on flexible endoscopes after use is often high and its removal is essential to allow effective disinfection, especially in the case of peracetic acid-based disinfectants, which are easily inactivated by organic material. Cleaning processes using conventional cleaners remove a variable but often sufficient amount of the bioburden. Some formulations based on peracetic acid are recommended by manufacturers for the cleaning step. We performed a systematic literature search and reviewed the available evidence to clarify the suitability of peracetic acid-based formulations for cleaning flexible endoscopes. A total of 243 studies were evaluated. No studies have yet demonstrated that peracetic acid-based cleaners are as effective as conventional cleaners. Some peracetic acid-based formulations have demonstrated some biofilm-cleaning effects and no biofilm-fixation potential, while others have a limited cleaning effect and a clear biofilm-fixation potential. All published data demonstrated a limited blood cleaning effect and a substantial blood and nerve tissue fixation potential of peracetic acid. No evidence-based guidelines on reprocessing flexible endoscopes currently recommend using cleaners containing peracetic acid, but some guidelines clearly recommend not using them because of their fixation potential. Evidence from some outbreaks, especially those involving highly multidrug-resistant gram-negative pathogens, indicated that disinfection using peracetic acid may be insufficient if the preceding cleaning step is not performed adequately. Based on this review we conclude that peracetic acid-based formulations should not be used for cleaning flexible endoscopes.

Quality assurance in endoscopy nursing

Since the 1960s quality assurance has become an integral part of medicine and nursing. The aims of quality assurance cover patient and staff safety and satisfaction, economical factors and the implementation of health care policy. Endoscopy units can be established in hospitals, primary care or ambulatory endoscopy centres. The quality of endoscopy facilities should be the same irrespective where endoscopy is carried out. Endoscopy staff is responsible for individualised, comprehensive patient care, technical assistance including reprocessing, documentation and management of endoscopy units. Quality criteria for endoscopy nursing cover pre, intra and post procedure care. However, a complete separation between clinical medical and nursing outcome criteria is often difficult in Endoscopy, as the clinical interventions are a combination of both medical and nursing actions. It is the combined effort of all staff with the support from the health care provider that leads to a high quality of patient care in Endoscopy.

[Gastrointestinal endoscopy and infection]

During a gastrointestinal endoscopy, the device crosses natural cavities with always commensal bacterial flora, sometimes pathogenic flora. In all cases, the device is contaminated after the exam. The lack of effective disinfection exposes to the risks of transmission of germs. The infectious risk depends on the patient, the endoscopic procedure as well as on the technique of disinfection. The bacteraemia is usually not clinically significant. The endoscopic transmission of the germs from a patient to another one is very rare and is mostly due to a defect of disinfection. The procedures for disinfecting equipment should be known, established and controlled.

Health care-associated transmission of hepatitis B and C viruses in endoscopy units

The risk for potential transmission of infectious agents during gastrointestinal (GI) endoscopy is concerning for patients and physicians. However, the instance of infection transmission remains rare after GI endoscopy procedures, with an estimated frequency of 1 in 1.8 million procedures. Endoscopy-related infection may occur when microorganisms are spread or transmitted from patient to patient by contaminated endoscopic or accessory equipments; from the GI tract through the bloodstream during endoscopy to susceptible organs or prostheses, or spread to adjacent tissues that are breached as a result of the endoscopy procedure; or from patients to endoscopy personnel and perhaps from endoscopy personnel to patients. Proper cleaning, disinfection, and reprocessing of endoscopies and accessories, and appropriate administration of intravenous drugs help to minimize the risk for infection transmission.

Gastrointestinal endoscopes cleaned without detergent substance following an automated endoscope washer/disinfector dysfunction

OBJECTIVE

To report cases of gastrointestinal endoscopies performed with endoscopes that were reprocessed without detergent substance during a period of dysfunction of the automated endoscope reprocessor (AER).

METHOD

A dysfunction of the AER for the cycles requiring detergent substance was reported at the Grenoble University Hospital on March 2005. During this period, 72 patients had potentially been exposed to a contaminated endoscope. A recall procedure was organized and serologic tests (HIV, HCV, HBV) were performed 3 and 6 months after the AER incident.

RESULTS

Within the 72 patients convened, 56 (77.8%) were seen in consultation and accepted the serologic screening. Finally, serologic screening was done for 59 patients (81.9%) and no seroconversion for HIV, HCV, or HBV was observed. The final attrition rate was 13 patients (18.1%).

CONCLUSION

No viral infection was transmitted during the AER dysfunction. After this AER incident, the monitoring of the endoscopic procedures and the traceability of the cleaning process were both improved to prevent further incidents.

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.

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Efficacy of electrolyzed acid water in reprocessing patient-used flexible upper endoscopes: Comparison with 2% alkaline glutaraldehyde

BACKGROUND AND AIM

Two percent glutaraldehyde, the most widely used liquid chemical germicide (LCG), may be hazardous to patients and medical personnel. Alternatives to glutaraldehyde, such as electrolyzed acid water (EAW), are being developed, but data from well-controlled studies with patient-used endoscopes are rare. The purpose of the present paper was to evaluate the high-level disinfection capability of EAW and compare it with glutaraldehyde.

METHODS

A random sample of 125 endoscopes was collected immediately after upper endoscopic examination. After careful manual cleaning, endoscopes were divided into a glutaraldehyde and EAW group. After the disinfection procedure, samples from working channel (S-1), insertion tube (S-2), umbilical cord (S-3), and angulation knob (S-4) were taken and cultured. Another twenty endoscopes were experimentally contaminated with hepatitis B virus (HBV) and samples were collected after contamination (T-1), after manual cleaning (T-2), and after final disinfection (T-3). Polymerase chain reaction (PCR) for HBV-DNA was performed.

RESULTS

In the EAW group, culture-positive rates were 3.2% in S-1, 9.5% in S-2, 3.2% in S-3, and 27.0% in the S-4 samples. There was no significant difference between the EAW and glutaraldehyde groups for all sampling sites. However, in both groups, disinfection of the angulation knobs (S-4) was less efficient than the others. For the T-1 site, HBV-DNA was detected from all of them, and in 95% (19/20) of T-2. However, HBV-DNA was not detected from T-3 samples.

CONCLUSIONS

Electrolyzed acid water is as efficient as glutaraldehyde in eliminating bacteria from patient-used endoscopes. After disinfection procedures using both methods, HBV-DNA was not detected from any endoscopes experimentally contaminated with HBV-positive mixed sera. However, some bacteria may remain on the surface of the endoscopes. Therefore, more careful precleaning of the endoscopes may help achieve high-level disinfection in the clinical setting.

Reprocessing endoscopes: United States perspective

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.

Multi-society guideline for reprocessing flexible gastrointestinal endoscopes. Society for Healthcare Epidemiology of America

Flexible gastrointestinal endoscopy is a valuable diagnostic and therapeutic tool for the care of patients with gastrointestinal and pancreaticobiliary disorders. Compliance with accepted guidelines for the reprocessing of gastrointestinal endoscopes between patients is critical to the safety and success of their use. When these guidelines are followed, pathogen transmission can be effectively prevented. Increased efforts and resources should be directed to improve compliance with these guidelines. Further research in the area of gastrointestinal endoscope reprocessing should be encouraged. The organizations that endorsed this guideline are committed to assisting the FDA and manufacturers in addressing critical infection control issues in gastrointestinal device reprocessing.

Safety of technology: infection control standards in endoscopy

Transmission of infection related to gastrointestinal endoscopy continues to be a subject of much discussion. The principles of infection control during endoscopy are reviewed. Guidelines set forth by a number of gastrointestinal endoscopy associations have emphasized the need for meticulous cleaning of endoscopes immediately after use, followed by appropriate disinfection, rinsing and drying. Most, if not all, episodes of transmission of infection during endoscopy are associated with lapses in cleaning and disinfection protocols. The need for universal compliance with infection control standards, and for the development of strategies to achieve such compliance, is highlighted.

Analysis of HBV infection after blood transfusion in Japan through investigation of a comprehensive donor specimen repository

BACKGROUND

To understand the risk of transfusion-transmitted viral infection, it is important to precisely assess cases of infection that follow transfusion.

STUDY DESIGN AND METHODS

HBV infections noted after transfusion in 1997, 1998, and 1999 were analyzed. Transfusion in all these cases was performed before NAT was adopted for donor screening. To detect viral infection, PCR and serologic tests for HBV were performed retrospectively on all blood samples from implicated donors that had been stored in a frozen state after each donation. The concentration of HBV genome was measured in HBV-positive blood samples.

RESULTS

One hundred three cases of HBV infection were analyzed; of these, only 16, including at least 10 infections due to window-period (HBsAg-positive by reverse particle hemagglutination assay) donations, were confirmed by further testing to be related to transfusion. The concentrations of HBV genome were very low in four blood samples (<50, 400, 500, and 800 genome equivalents/mL of plasma).

CONCLUSIONS

The remaining risk of transfusion transmission of HBV infection before the adoption of NAT was mainly due to window-period donations, including one that was made before the HBV genome was detectable by PCR. However, it was determined that transfusion was not responsible in many cases for HBV infection after transfusion.

Preventing the spread of hepatitis B and C viruses: where are germicides relevant?

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are the most prevalent bloodborne pathogens. Infections caused by these organisms can become chronic and may lead to liver cirrhosis and carcinoma. Limited chemotherapy is now available, but only HBV can be prevented through vaccination. Both viruses are enveloped and relatively sensitive to many physical and chemical agents; their ability to survive in the environment may not be as high as often believed. As a result, their spread occurs mainly through direct parenteral or percutaneous exposure to tainted body fluids and tissues. Careful screening of and avoiding contact with such materials remain the most effective means of protection. Nevertheless, the indirect spread of these viruses, although much less common, can occur when objects that are freshly contaminated with tainted blood enter the body or contact damaged skin. Germicidal chemicals are important in the prevention of HBV and HCV spread through shared injection devices, sharps used in personal services (such as tattooing and body piercing), and heat-sensitive medical/dental devices (such as flexible endoscopes) and in the cleanup of blood spills. Microbicides in vaginal gels may also interrupt their transmission. General-purpose environmental disinfection is unlikely to play a significant role in the prevention of the transmission of these viruses. Testing of low-level disinfectants and label claims for such products against HBV and HCV should be discouraged. Both viruses remain difficult to work with in the laboratory, but closely related animal viruses (such as the duck HBV) and the bovine viral diarrhea virus show considerable promise as surrogates for HBV and HCV, respectively. Although progress in the culturing of HBV and HCV is still underway, critical issues on virus survival and inactivation should be addressed with the use of these surrogates.

The emerging nosocomial pathogens Cryptosporidium, Escherichia coli O157:H7, Helicobacter pylori, and hepatitis C: epidemiology, environmental survival, efficacy of disinfection, and control measures

New and emerging infectious diseases pose a threat to public health and may be responsible for nosocomial outbreaks. Cryptosporidium parvum and Escherichia coli are gastrointestinal pathogens that have caused nosocomial infections via person-to-person transmission, environmental contamination, or contaminated water or food. Helicobacter pylori has been transmitted via inadequately disinfected endoscopes. Finally, hepatitis C may be acquired by healthcare personnel by percutaneous or mucous membrane exposure to blood or between patients by use of contaminated blood products or via environmental contamination. Rigorous adherence to Standard Precautions, Contact Precautions for patients with infectious diarrhea, disinfection of environmental surfaces, and appropriate disinfection of endoscopes are adequate to prevent nosocomial acquisition of these pathogens.

Reprocessing of flexible endoscopes

Proper reprocessing of endoscopes prevents the risk of transmission of infection between patients. Meticulous mechanical cleaning is the most important step as it removes the majority of the contaminating bacteria. It should be performed before manual or automatic disinfection. High-level disinfection involves total immersion of the endoscope in a liquid chemical germicide (LCG) at a preset temperature and concentration for a pre-determined period of time. Subsequent rinsing and drying are essential steps to remove the chemical solution and prevent bacterial colonization during storage. Endoscopy units that are used for more than 50 procedures per week may benefit from cleaning in an automatic endoscope reprocessor (AER). This allows automated exposure of the endoscope to the LCG with subsequent flushing and drying of the channels, and minimizes staff exposure to the LCG. Reprocessing should be performed by trained and accredited personnel according to written guidelines or standards of practice as defined by professional societies. Regular monitoring of the reprocessing process is important for quality control and in ensuring patients' safety.