Recent advances in epidemiology and prevention of gastrointestinal endoscopy related infections

Confirmatory Virucidal Activity of Ionised Active Water S-100® on the SARS-CoV-2 Virus

Ionised active water S-100® has been proposed as an original solution for use in dermocosmetics and for the treatment of wounds such as burns and atopic dermatitis. Among the mechanisms of action that are not completely understood, an antimicrobial activity would appear to be important. In the context of the COVID-19 pandemic, we assessed the inactivating efficacy of this solution on SARS-CoV-2 based on the recommendations of the NF-EN-14476+A2 standard. The tests carried out demonstrated that ionised active water S-100® 40% has a virucidal activity on SARS-CoV-2 which is at least 3.1 log after a contact time of 30 seconds and 3.5 log after two minutes at 20°C under clean conditions. Assays were also performed at 4°C and 37°C, and the results obtained are identical to those obtained at 20°C. This demonstration of the virucidal effect of ionised water against SARS-CoV-2 paves the way for the development of usage as an alternative disinfectant in SARS-CoV-2 control.

Comparison of channel sampling methods and brush heads in surveillance culture of endoscope reprocessing: A propensity score matching and paired study

BACKGROUND

Endoscopy-related infections have caused multiple outbreaks. The importance of surveillance culture is gradually recognized, but sampling techniques are not consistent in many guidelines. It is unclear whether the Flush-Brush-Flush sampling method (FBFSM) is more sensitive than the conventional flush sampling method (CFSM) and whether different sampling brushes have different effects.

METHODS

The propensity score matching method was done with two matching ways, 1:1 nearest neighbor propensity score matching and full matching was used to analyze the surveillance culture data collected by FBFSM and CFSM. We fit a confounder-adjusted multiple generalized linear logistic regression model to estimate the marginal odds ratio (OR). A paired study was applied to compare the sampling effect of polyurethane foam (PU) head brush and polyamide (PA) head brush.

RESULT

From 2016 to 2020, 316 reprocessed endoscope samples were collected from all 59 endoscopy centers in Tianjin. About 279 (88.3%) reprocessed endoscopes met the threshold of Chinese national standards (<20 CFU/Channel). The qualified rate of reprocessed endoscopes sampling by CFSM (91.8%) and FBFSM (81.6%) was statistically different (p < 0.05). The adjusted OR by full matching for FBFSM was 7.98 (95% confidence interval: 3.35-21.78). Forty one pairs of colonoscopes, after reprocessing from 27 centers, were tested by PA and PU brushes, and no difference was found in microbial recovery.

CONCLUSION

FBFSM was confirmed to be a more sensitive sampling technique. PU and PA brushes had no significant difference in sampling effect.

Establishment of a quality control circle to reduce biofilm formation in flexible endoscopes by improvement of qualified cleaning rate

Objective

In recent years, the Emergency Care Research Institute has advised that endoscope cleaning is of considerable importance. In the present study, a quality control circle (QCC) was used to reduce the formation of biofilms in flexible endoscopes within one hospital in Guangdong Province, China.

Methods

During reprocessing of 235 flexible endoscopes in the urology surgical suite, adenosine triphosphate (ATP) detection was used to monitor the efficacy of biofilm removal. The internal and external parts of flexible endoscopes were used as sampling sites by means of the flushing and smudge methods, respectively. When the two results reached the standard of less than 500 relative light units/piece at the same time, endoscopic biofilm clearance was considered to be qualified. A QCC was established to implement a 10-step plan-do-check-act model.

Results

The baseline qualified rate (i.e., ATP monitoring pass rate) during reprocessing of 235 flexible endoscopes was 50%. During the study, the qualified rate increased to 85.29% after establishment of the QCC. During reprocessing of 150 flexible endoscopes in the following 6 months, the qualified rate remained at 90%.

Conclusion

Establishment of the QCC improved the removal of biofilm from flexible endoscopes in the urology surgical suite.

The importance of sampling technique and rinse water for assessing flexible gastrointestinal endoscope reprocessing: A 3-year study covering 59 centers

BACKGROUND

Various guidelines recommend several sampling techniques to verify endoscope reprocessing, but a comparative study of the efficiency for recovering microorganisms was rare. Our goal was to compare different sampling techniques for the postreprocessing endoscope to assess residual bacterial contamination and analysis of the critical factors affecting the endoscope reprocessing failure.

METHODS

From 2016 to 2018, 3 techniques, the conventional flushing sampling method, flush-brush-flush sampling method (FBFSM), and pump-assisted sampling method (PASM), were compared covering all 59 endoscope units in Tianjin, China.

RESULTS

A total of 237 (84.64%) flushing channel samples and 110 (61.11%) final rinse water samples met the Chinese national standard. The univariate analysis showed that the qualified rates of endoscope reprocessing sampled by PASM (65.52%) and FBFSM (75%) were significantly lower than those of the conventional flushing sampling method (91.38%). Five other factors, including the final rinse water, dry, and hospital level, were potential factors besides sample technique. The multivariate logistic analysis indicated only 2 factors (sampling technique and final rinse water) remained in the model. FBFSM, PASM, and the purified water were significantly associated with the odds of endoscope reprocessing failure, with the odds ratio (95% confidence interval) of which were 4.206 (1.757-10.067), 5.326 (2.463-11.645), and 0.309 (0.137-0.695), respectively.

CONCLUSIONS

The problem of residual microorganisms of the postreprocessing endoscope was severe. Sampling technique and final rinse water were critical for endoscope reprocessing verification.

Bacterial presence on flexible endoscopes vs time since disinfection

AIM

To correlate the length of endoscope hang time and number of bacteria cultured prior to use.

METHODS

Prospectively, we cultured specimens from 19 gastroscopes, 24 colonoscopes and 5 side viewing duodenoscopes during the period of 2011 to 2015. A total of 164 results had complete data denoting date of cleansing, number of days stored and culture results. All scopes underwent initial cleaning in the endoscopy suite utilizing tap water, and then manually cleaned and flushed. High level disinfection was achieved with a Medivator^© DSD (Medivator Inc., United States) automated endoscope reprocessor following manufacturer instructions, with Glutacide^® (Pharmax Limited, Canada), a 2% glutaraldehyde solution. After disinfection, all scopes were stored in dust free, unfiltered commercial cabinets for up to 7 d. Prior to use, all scopes were sampled and plated on sheep blood agar for 48 h; the colony count was obtained from each plate. The length of endoscope hang time and bacterial load was analyzed utilizing unpaired t-tests. The overall percentage of positive and negative cultures for each type of endoscope was also calculated.

RESULTS

All culture results were within the acceptable range (less than 200 cfu/mL). One colonoscope cultured 80 cfu/mL after hanging for 1 d, which was the highest count. ERCP scopes cultured at most 10 cfu, this occurred after 2 and 7 d, and gastroscopes cultured 50 cfu/mL at most, at 1 d. Most cultures were negative for growth, irrespective of the length of hang time. Furthermore, all scopes, with the exception of one colonoscope which had two positive cultures (each of 10 cfu/mL), had at most one positive culture. There was no significant difference in the number of bacteria cultured after 1 d compared to 7 d when all scopes were combined (day 2: P = 0.515; day 3: P = identical; day 4: P = 0.071; day 5: P = 0.470; day 6: P = 0.584; day 7: P = 0.575). There was also no significant difference in the number of bacteria cultured after 1 day compared to 7 d for gastroscopes (day 2: P = 0.895; day 3: P = identical; day 4: P = identical; day 5: P = 0.893; day 6: P = identical; day 7: P = 0.756), colonoscopes (day 2: P = 0.489; day 4: P = 0.493; day 5: P = 0.324; day 6: P = 0.526; day 7: P = identical), or ERCP scopes (day 2: P = identical; day 7: P = 0.685).

CONCLUSION

There is no correlation between hang time and bacterial load. Endoscopes do not need to be reprocessed if reused within a period of 7 d.

Clinical Practice Guidelines for Endoscope Reprocessing

Gastrointestinal endoscopy is effective and safe for the screening, diagnosis, and treatment of gastrointestinal disease. However, issues regarding endoscope-transmitted infections are emerging. Many countries have established and continuously revise guidelines for endoscope reprocessing in order to prevent infections. While there are common processes used in endoscope reprocessing, differences exist among these guidelines. It is important that the reprocessing of gastrointestinal endoscopes be carried out in accordance with the recommendations for each step of the process.

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.

Residual bioburden in reprocessed side-view endoscopes used for endoscopic retrograde cholangiopancreatography (ERCP)

BACKGROUND AND STUDY AIM

Worldwide some endoscopy units routinely continue to use manual reprocessing techniques for disinfection of side-view endoscopes. The aim of this study was to evaluate the outcome quality of manual reprocessing techniques for removal and inactivation of the bioburden from side-view endoscopes used for endoscopic retrograde cholangiopancreatography (ERCP) in a tertiary referral endotherapy unit in Sri Lanka.

METHODS

102 samples obtained from two different flexible side-view endoscopes (Olympus TJF Q 180V and Olympus TJF 160 R) were tested for microbial growth. Three samples were collected each time; one swab from the tip before and another after manual reprocessing. The third sample was collected by flushing the working channel with sterile normal saline after manual reprocessing. Microorganisms were identified by culturing the samples.

RESULT

: After reprocessing, culture-positive rates were 20 % and 9 % for the samples obtained from the tip and the working channel of the side-view endoscopes, respectively. Klebsiella spp. and Candida spp. were found to be the commonest microorganisms in the samples from the tips and from the working channels, respectively, of the reprocessed side-view endoscopes.

CONCLUSION

There is a high culture-positive rate after reprocessing of the side-view endoscopes using the manual reprocessing procedure, despite strict adherence to the protocol for reprocessing.

Evaluation of detergents and contact time on biofilm removal from flexible endoscopes

BACKGROUND

The formation of endoscopic biofilm reduces the results of cleaning and disinfection and may increase nosocomial infection. This study aims to evaluate the effects of various detergents and different contact time on the removal of biofilm on flexible endoscopes based on an artificial biofilm model.

METHOD

Endoscopic biofilm model was established and treated with various detergents (detergent 1, Rapid Multi-Enzyme; detergent 2, Scopezime; and detergent 3, Intercept) for 3, 5, and 7 minutes. Escherichia coli viable counts and biofilm changes were measured by colony counting and electron microscopy scanning, respectively.

RESULTS

Statistical differences were observed between various detergents and the control group (P < .001) but not among the different contact time groups (3, 5, and 7 minutes, P > .05). Multiple comparisons showed that statistical differences in residual biofilm bacteria were observed between the detergents and the control (P < .001). Significant differences (P < .001) in residual biofilm bacteria existed between the 2 enzymatic detergents and the nonenzymatic detergent group, whereas no significant difference was observed between the 2 enzymatic detergents (P > .05). No crossover effect was observed between various detergent groups, contact time, and the control group (P > .05). Electron microscopy scanning revealed that, after various detergents and contact time of 3, 5, and 7 minutes, the residual biofilm in the enzymatic detergent group was significantly more than that of the nonenzymatic detergent group. No significant difference was observed among the groups with the same detergent and different contact time.

CONCLUSION

Significantly more biofilm bacteria and biofilms were found in the enzymatic detergent groups compared with the nonenzymatic detergent group, whereas no significant difference was observed among 3, 5, and 7 minutes groups.

A review of current disinfectants for gastrointestinal endoscopic reprocessing

Gastrointestinal endoscopy is gaining popularity for diagnostic and therapeutic purposes. However, concerns over endoscope-related nosocomial infections are increasing, together with interest by the general public in safe and efficient endoscopy. For this reason, reprocessing the gastrointestinal endoscope is an important step for effective performance of endoscopy. Disinfectants are essential to the endoscope reprocessing procedure. Before selecting an appropriate disinfectant, their characteristics, limitations and means of use must be fully understood. Herein, we review the characteristics of several currently available disinfectants, including their uses, potency, advantages, and disadvantages. Most disinfectants can be used to reprocess gastrointestinal endoscopes if the manufacturer's guidelines are followed. The selection and use of a suitable disinfectant depends on the individual circumstances of each endoscopy suite.

In vitro bactericidal activity against periodontopathic bacteria by electrolyzed ion-reduced water

As typical periodontopathic bacteria, Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) were exposed to electrolyzed ion-reduced water (ERI) and ERI containing 1% sodium carboxymethylcellulose (CMC-Na) (ERI-1% CMC-Na), and the time course of their bactericidal action was evaluated. More than 99% of each bacteria species were killed after exposure to each solution for 15 sec. In addition, 1% CMC-Na, which was added to prolong bactericidal action, did not affect the bactericidal action of ERI. Its bactericidal action was concentration-dependent. No viable P. gingivalis bacteria were observed at a concentration of 15% of the undiluted solution and no viable A. actinomycetemcomitans bacteria were observed at a concentration of 50%, indicating differences in the bactericidal action of ERI for the two bacteria species. These results suggest that ERI may be extremely useful in preventing and treating periodontal diseases.

String capsule endoscopy for screening and surveillance of esophageal varices in patients with cirrhosis

BACKGROUND

EGD is the gold standard for the screening and surveillance of esophageal varices. A less invasive, safer and sedationless alternative procedure is needed.

OBJECTIVE

To assess the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) as well as the beyond the chance agreement (kappa index), of string capsule endoscopy (SCE) in the diagnosis of esophageal varices.

METHODS

Cirrhotic patients underwent string capsule endoscopy (SCE) and EGD for screening and surveillance purposes. Varices were graded at EGD and SCE as small, medium and large. Descriptors at SCE were added as follows: PLUS, for the presence of red wale signs or, MINUS for their absence, irrespective of the estimated variceal size. Clinically significant varices were defined by their size (medium/large at either EGD or SCE) and/or, the PLUS descriptor irrespective of the estimated size at SCE. Sensitivity, specificity, PPV, NPV, accuracy and kappa index were calculated. Procedure time, procedure-related discomfort and patient's preference were documented.

RESULTS

100 patients (33 for screening and 67 for surveillance) were enrolled. The sensitivity and specificity of SCE for clinically significant varices when using the PLUS/MINUS descriptors were 82% and 90%, respectively with a PPV of 84% and NPV of 89% and a kappa of 0.73.

CONCLUSION

String capsule endoscopy had an acceptable sensitivity and specificity for the diagnosis of clinically significant esophageal varices but the lack of air insufflation still hampers its correlation with the grading used with EGD.

High cecal intubation rates with a new computer-assisted colonoscope: a feasibility study

OBJECTIVES

The acceptability of colonoscopy as a screening test is limited by several factors including patient discomfort. A new self-propelled colonoscope, the Invendo SC20 (Invendo Medical GmbH), may be helpful in reducing sedation. It consists of a sheathed endoscope contained within an "inverted sleeve," and having an instrument channel and an electrohydraulic bendable tip; it is steered using a handheld device and propelled by a motorized drive unit. This study assessed the safety and efficacy of this new endoscope in volunteers undergoing colorectal cancer (CRC) screening.

METHODS

Paid healthy volunteers aged 50-70 years and eligible for screening colonoscopy were included. Total colonoscopy using carbon dioxide insufflation or water instillation on demand was attempted, with all procedures being started without sedation. The main outcome parameters were safety and the cecal intubation rate.

RESULTS

A total of 61 volunteers participated (34 men and 27 women; mean age 57.5 years). The cecum was reached in 60 volunteers (cecal intubation rate of 98.4%). The median time to reach the cecum was 15 min (range 7-53.5). Sedation was given in three individuals (4.9%). On withdrawal (median time 15 min), the material for histological evaluation was obtained from 33 polyps (mean size 4.8 mm) in 23 people by biopsy forceps or snare. No device-related complications were encountered.

CONCLUSIONS

A new computer-assisted colonoscope, controlled using a handheld device, showed excellent cecal intubation rates during screening examinations, with sedation required in only ~ 5% of screenees. Further clinical and comparative studies are warranted.

Current status of cleaning and disinfection for gastrointestinal endoscopy in China: a survey of 122 endoscopy units

BACKGROUND

Adequate compliance with the existing guidelines for cleaning and disinfection of gastrointestinal endoscopes and accessories is necessary to obtain high-level disinfection and prevent pathogen transmission.

AIM

To investigate cleaning and disinfection practice in China.

METHODS

A questionnaire with 21 questions concerning gastrointestinal endoscopy reprocessing was sent by e-mail to 189 endoscopy units in China.

RESULTS

One hundred and twenty-two (80.39%) of the 189 units responded. Compared with the low-workload units (<5000 procedures/year), the high-workload units (≥5000 procedures/year) had a significantly higher number of gastrointestinal endoscopes (25.8 ± 3.6 vs. 4.7 ± 1.8, p < 0.01) and the higher possessing rate of automated endoscope reprocessors (43.9% vs. 3.1%, p<0.01). Glutaraldehyde was the most commonly employed disinfectant (88.5%) in all the units. In 23/122 (18.8%) units, the exposure time to glutaraldehyde was <45 min in the case of infectious disease patients. Eighty-six of 122 (70.5%) units reused disposable materials, of which 21/86 (24.4%) reused disposable forceps and disposable polypectomy hooks, and 2/86 (1.6%) reused disposable injection needles intermittently.

CONCLUSION

Although gastrointestinal endoscopy has developed rapidly in China in the past decade, there is still room for improvement in the practice of endoscopy reprocessing, especially in middle-sized and small cities.

Reducing infection risk in colonoscopy

Colonoscopy is a well recognized diagnostic and therapeutic tool. Endoscope reprocessing must be done correctly every time; a breach of protocol leading to transmission of infection has the potential to bring endoscopy to a halt. Standards exist that guide the practitioner in all health care settings to minimize the chance of transmission of infection. Safe injection practices and reprocessing of endoscopes using high-level disinfection and sterilization methods may help avert the risk of contracting possible infections during colonoscopy procedures.

EVOTECH endoscope cleaner and reprocessor (ECR) simulated-use and clinical-use evaluation of cleaning efficacy

BACKGROUND

The objective of this study was to perform simulated-use testing as well as a clinical study to assess the efficacy of the EVOTECH Endoscope Cleaner and Reprocessor (ECR) cleaning for flexible colonoscopes, duodenoscopes, gastroscopes and bronchoscopes. The main aim was to determine if the cleaning achieved using the ECR was at least equivalent to that achieved using optimal manual cleaning.

METHODS

Simulated-use testing consisted of inoculating all scope channels and two surface sites with Artificial Test Soil (ATS) containing 108 cfu/mL of Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans. Duodenoscopes, colonoscopes, and bronchoscopes (all Olympus endoscopes) were included in the simulated use testing. Each endoscope type was tested in triplicate and all channels and two surface sites were sampled for each scope. The clinical study evaluated patient-used duodenoscopes, bronchoscopes, colonoscopes, and gastroscopes (scopes used for emergency procedures were excluded) that had only a bedside flush prior to being processed in the ECR (i.e. no manual cleaning). There were 10 to 15 endoscopes evaluated post-cleaning and to ensure the entire ECR cycle was effective, 5 endoscopes were evaluated post-cleaning and post-high level disinfection. All channels and two external surface locations were sampled to evaluate the residual organic and microbial load. Effective cleaning of endoscope surfaces and channels was deemed to have been achieved if there was < 6.4 microg/cm2 of residual protein, < 1.8 microg/cm2 of residual hemoglobin and < 4 Log10 viable bacteria/cm2. Published data indicate that routine manual cleaning can achieve these endpoints so the ECR cleaning efficacy must meet or exceed these to establish that the ECR cleaning cycle could replace manual cleaning

RESULTS

In the clinical study 75 patient-used scopes were evaluated post cleaning and 98.8% of surfaces and 99.7% of lumens met or surpassed the cleaning endpoints set for protein, hemoglobin and bioburden residuals. In the simulated-use study 100% of the Olympus colonoscopes, duodenoscopes and bronchoscopes evaluated met or surpassed the cleaning endpoints set for protein, and bioburden residuals (hemoglobin was not evaluated).

CONCLUSIONS

The ECR cleaning cycle provides an effective automated approach that ensures surfaces and channels of flexible endoscopes are adequately cleaned after having only a bedside flush but no manual cleaning. It is crucial to note that endoscopes used for emergency procedures or where reprocessing is delayed for more than one hour MUST still be manually cleaned prior to placing them in the ECR.

A study of the efficacy of bacterial biofilm cleanout for gastrointestinal endoscopes

AIM: To compare the influence and clearance effect of enzymatic and non-enzymatic detergents against Escherichia coli (E. coli) biofilm on the inner surface of gastroscopes.

METHODS: Teflon tubes were incubated in a mixture of different detergents and E. coli culture (10⁶ CFU/mL) for 72 h at 15°C, and biofilms on the inner surface of the teflon tubes were analyzed by bacterial count and scanning electron microscopy. To evaluate the clearance effect of detergents, after biofilms were formed on the inner surface of Teflon tubes by 72 h lavage with E. coli culture, tubes were lavaged by enzymatic and non-enzymatic detergents at a speed of 250 mL/min, then biofilms on the inner surface were analyzed by bacterial count and scanning electron microscopy.

RESULTS: Non-enzymatic detergent had a better inhibition function on biofilm formation than enzymatic detergent as it reduced bacterial burden by 2.4 log compared with the control samples (P = 0.00). Inhibition function of enzymatic detergent was not significantly different to that of control samples and reduced bacterial burden by 0.2 log on average (P > 0.05). After lavaging at 250 mL/min for 3 min, no living bacteria were left in the tubes. Scanning electron microscopy observation showed biofilms became very loose by the high shear force effect.

CONCLUSION: Non-enzymatic detergent has a better inhibition effect on biofilm formation at room temperature. High speed pre-lavage and detergents are very important in temporal formed biofilm elimination.

Modeling microbial survival in buildup biofilm for complex medical devices

Background

Flexible endoscopes undergo repeated rounds of patient-use and reprocessing. Some evidence indicates that there is an accumulation or build-up of organic material that occurs over time in endoscope channels. This "buildup biofilm" (BBF) develops as a result of cyclical exposure to wet and dry phases during usage and reprocessing. This study investigated whether the BBF matrix represents a greater challenge to disinfectant efficacy and microbial eradication than traditional biofilm (TBF), which forms when a surface is constantly bathed in fluid.

Methods

Using the MBEC (Minimum Biofilm Eradication Concentration) system, a unique modelling approach was developed to evaluate microbial survival in BBF formed by repetitive cycles of drying, disinfectant exposure and re-exposure to the test organism. This model mimics the cumulative effect of the reprocessing protocol on flexible endoscopes. Glutaraldehyde (GLUT) and accelerated hydrogen peroxide (AHP) were evaluated to assess the killing of microbes in TBF and BBF.

Results

The data showed that the combination of an organic matrix and aldehyde disinfection quickly produced a protective BBF that facilitated high levels of organism survival. In cross-linked BBF formed under high nutrient conditions the maximum colony forming units (CFU) reached ~6 Log₁₀ CFU/peg. However, if an oxidizing agent was used for disinfection and if organic levels were kept low, organism survival did not occur. A key finding was that once established, the microbial load of BBF formed by GLUT exposure had a faster rate of accumulation than in TBF. The rate of biofilm survival post high-level disinfection (HLD) determined by the maximum Log₁₀CFU/initial Log₁₀CFU for E. faecalis and P. aeruginosa in BBF was 10 and 8.6 respectively; significantly different compared to a survival rate in TBF of ~2 for each organism. Data from indirect outgrowth testing demonstrated for the first time that there is organism survival in the matrix. Both TBF and BBF had surviving organisms when GLUT was used. For AHP survival was seen less frequently in BBF than in TBF.

Conclusion

This BBF model demonstrated for the first time that survival of a wide range of microorganisms does occur in BBF, with significantly more rapid outgrowth compared to TBF. This is most pronounced when GLUT is used compared to AHP. The data supports the need for meticulous cleaning of reprocessed endoscopes since the presence of organic material and microorganisms prevents effective disinfection when GLUT and AHP are used. However, cross-linking agents like GLUT are not as effective when there is BBF. The data from the MBEC model of BBF suggest that for flexible endoscopes that are repeatedly used and reprocessed, the assurance of effective high-level disinfection may decrease if BBF develops within the channels.

Endoscopy-related infection: relic of the past?

PURPOSE OF REVIEW

Recent outbreaks of nosocomial infection and pseudoinfection have been linked to contaminated endoscopes. This review summarizes the recent literature, analyzes the latest published information related to the epidemiology, examines potential causes for the outbreaks, and discusses current alternatives for preventing infection.

RECENT FINDINGS

A systematic follow-up of patients revealed that the risk of infection attributed to inadequate endoscope reprocessing was very low. Nevertheless, inadequate reprocessing practices are still considered the main culprit underlying contamination from endoscopy procedures. Moreover, standards of care are difficult to maintain given the numerous inconsistencies that exist among reprocessing guidelines and manufacturer's recommended practices. Exposure to contaminated equipment could be prevented through better reprocessing practices and adherence to decontamination guidelines. Recent literature reinforces the need for endoscopy drying after each reprocessing cycle, endoscope reprocessing after short periods of disuse, surveillance, and for a coordinated approach to handle postcontamination responses. Additional analyses such as health technology assessment and cost analysis are needed to identify control alternatives that are most effective.

SUMMARY

Although the risk of endoscopy-related infection is very low, continued efforts are needed to ensure that quality is maintained during endoscope reprocessing to reduce the incidence of endoscopy-related infections.

A motor-driven single-use colonoscope controlled with a hand-held device: a feasibility study in volunteers

BACKGROUND

Several new instruments have been developed in the effort to improve the acceptance of colonoscopy for colorectal cancer screening. A new colonoscope, the Invendoscope, is presented here. It consists of an endoscopic sheath with an inverted sleeve, instrument channel, and an electrohydraulic deflecting tip. The instrument is steered by a hand-held device and propelled by a motorized drive unit.

OBJECTIVE

Our purpose was to evaluate the feasibility of the new Invendoscope SC40.

DESIGN

Prospective single-arm pilot study over 2 time periods using 2 different instrument prototypes (170 and 180/200 cm).

PATIENTS

Thirty-four healthy volunteers (19 men, mean age 49.7 years). Technical instrument defects led to premature termination in 5 additional volunteers during the 2 study periods (4 in phase 1, 1 in phase 2), who were excluded from further analysis.

INTERVENTIONS

Total colonoscopy was attempted, with all procedures being performed without sedation.

MAIN OUTCOME MEASUREMENTS

Cecal intubation rate.

RESULTS

The cecum was reached in 82% of the 34 cases (95% CI, 66%-92%), with better results in period 2 than in period 1 (90% vs 79%); of the 6 incomplete examinations, 4 reached the mid transverse colon or beyond and 2 were stopped in the sigmoid colon because of pain. The volunteer rating showed a mean score of 1.96 (range 1-6; 1 = no discomfort). No complications were encountered.

LIMITATIONS

No data regarding diagnostic accuracy and no data comparing the instrument with conventional colonoscopy are available as yet.

CONCLUSIONS

This pilot proof-of-principle study of a new motor-driven colonoscope showed promising cecal intubation rates and an absence of pain in 92% of cases. Further clinical and comparative studies are warranted.

Peri-procedure pharmacotherapy, preparation, and infection control

Minimizing endoscopic complications includes attention to the details about each patient's current medical condition before they undergo an invasive procedure. This article focuses on critical issues about proper preparation for endoscopic procedures and examines potential modifications to a patient's medical regimen near the time of an endoscopic procedure, highlighting recently published standards and guidelines. This article also reviews important issues related to infection control in endoscopy.

Bacterial biofilms within the clinical setting: what healthcare professionals should know

Bacterial biofilm formation is the prevailing microbial lifestyle in natural and manmade environments and occurs on all surface types. Biofilm formation develops in several phases and is influenced by various parameters, both environmental and inherent to the attaching cell. Biofilms also serve as protective niches for particular pathogens when outside a host. Although it is accepted that biofilms are ubiquitous in nature, the significance of biofilms in clinical settings, especially with regard to their role in medical-related infections, is often underestimated. It has been found that several aspects of human pathogenesis within a clinical context are directly related to biofilm development. Various types of surfaces in clinical settings are prone to biofilm development and an increased risk of disease may be a direct consequence of their formation. This review describes the process of biofilm formation, highlights the importance of bacterial associations with surfaces in clinical settings and describes various methods for biofilm visualization and control.

Experimental evaluation of an automated endoscope reprocessor with in situ generation of peracetic acid for disinfection of semicritical devices

OBJECTIVE

To evaluate the effectiveness of a high-level disinfection solution generated inside an endoscope processing system for decontaminating external and internal surfaces of experimentally contaminated heat-sensitive medical devices.

METHODS

The American Society for Testing and Materials Simulated-Use Test protocol (E1837-02), which incorporates a soil load in each inoculum, was used to evaluate the efficacy of the system when processing 4 common types of endoscopes contaminated separately with 5 types of nosocomial pathogens: Pseudomonas aeruginosa (ATCC 15442), spores of Clostridium difficile (ATCC 9689), a glutaraldehyde-resistant strain of Mycobacterium chelonae, a vancomycin-resistant strain of Enterococcus faecalis, and a methicillin-resistant strain of Staphylococcus aureus. Rinse solution samples from channels and from surfaces of the processed endoscopes were tested for any microbicidal residues.

RESULTS

For all organisms tested, the baseline level of contamination of the endoscopes ranged from 5 log(10) to greater than 7 log(10) at each external surface site and internal channel. All tests showed reductions in viability of the test organisms to undetectable levels. All rinse solution samples from external and internal sites of the endoscopes proved to be free of any residual microbicidal activity.

CONCLUSIONS

The endoscope reprocessor, with its processor-generated high-level disinfection solution, successfully reduced the numbers of selected, clinically relevant pathogens to undetectable levels both in the channels and on the outside surfaces of the 4 representative endoscopes tested in this study.

Using an efficient biofilm detaching agent: an essential step for the improvement of endoscope reprocessing protocols

Biofilms develop inside endoscope channels even when valid endoscope reprocessing protocols are applied. The use of an efficient biocide is not sufficient if the channels are not cleaned thoroughly prior to disinfection. This study compared new anti-biofilm combinations of detachment promoting agents with a cleaning product in current use. Tests were performed using Teflon tubing and a contamination device that reproduces conditions that are prevalent during endoscopy. Products were subjected to static+brushing or dynamic treatments, and their ability to remove a preformed biofilm was assessed. The residual biofilm after treatment was assessed and compared with untreated controls. The percentage of surface covered by biofilm was measured after staining with crystal violet. Culturable bacteria levels were determined by plating the bacteria scraped from the tubing surface and counting the colony-forming units (CFU). Further tests were performed on actual endoscopes that had been contaminated artificially. Biofilm removal was confirmed by scanning electron microscopy. This study showed that the new anti-biofilm products prevented the build-up of biofilm and removed a mature biofilm (approximately 10(8)CFU/cm(2)), whereas protocols based on detergent-disinfectants containing quaternary ammonium compounds showed low efficacy as these protocols and products fixed the biofilm on the endoscope surfaces. The new procedure and agents represent a new approach to biofilm control that may improve the efficacy of endoscope reprocessing, and reduce the risk of transmitting infections.