Enzymatic detergent reuse in gastroscope processing: a potential source of microorganism transmission.

OBJECTIVE: to evaluate the potential contamination of enzymatic detergent from its reuse and to identify the microbiological profile in the solution used to clean gastrointestinal endoscopic devices. METHOD: cross-sectional study based on microbiological analysis of 76 aliquots of 19 different enzymatic detergent solutions used to clean endoscopic devices. The aliquots were homogenized, subjected to Millipore® 0.45 µm membrane filtration and the presumptive identification of microorganisms was performed by biochemical-physiological methods according to previously established specific bacterial groups that are of clinical and epidemiological relevance. RESULTS: the mean values, as well as the standard deviation and the median, of the enzymatic detergent microbial load increased as the solution was reused. There was a significant difference between the means of after first use and after fifth reuse. A total of 97 microorganisms were identified, with predominance of the coagulase-negative Staphylococcus, Pseudomonas spp., Klebsiella spp., Enterobacter spp. genus, and Escherichia coli species. CONCLUSION: the reuse of the enzymatic detergent solution is a risk to the safe processing of endoscopic devices, evidenced by its contamination with pathogenic potential microorganisms, since the enzymatic detergent has no bactericidal property and can contribute as an important source for outbreaks in patients under such procedures.

Evaluation of 12-Week Shelf Life of Patient-Ready Endoscopes.

Current research suggests that for certain types of gastrointestinal endoscopes, longer shelf life (the interval of storage after which endoscopes should be reprocessed before their reuse) may not increase the likelihood of endoscope contamination. Scope contamination may, in fact, be related primarily to either inadequate disinfection processes or inadvertent contamination during storage, not to duration of storage. The purpose of this study evaluated the presence of bacteria and fungus following liquid chemical sterilization in colonoscopes and gastroscopes, after 12 weeks of shelf life during which time personal protective equipment was used during endoscope storage cabinet access. We stored four colonoscopes and two gastroscopes in a cabinet for 12 weeks after liquid chemical sterilization and the cabinet was only accessed during the 12-week period wearing personal protective equipment (gown and gloves). Scopes were tested for bacteria and fungus at the end of 12 weeks. No bacteria or fungus grew on any of the scopes. This study provides further support that contaminated endoscopes may be related to either inadequate disinfection or contamination during storage, not shelf life.

Evaluation of adenosine triphosphate test for cleaning assessment of gastroscopes and the effect on workload in a busy endoscopy center.

OBJECTIVE: Using adenosine triphosphate (ATP) tests to assess manual cleaning of gastroscopes and to determine the associated workload in a busy endoscopy unit. METHODS: Patient-used gastroscopes were sampled before and after cleaning to assess ATP levels, bioburden, and protein. Samples were collected by flushing 20 mL of sterile water through the biopsy port to the distal end. Time spent for reprocessing and performing the ATP test was recorded. RESULTS: Twenty-four samples were collected from 10 gastroscopes. After manual cleaning, 14/24 (58.3%) samples had no microbial growth (mean, 21 colony-forming units/cm2), and in 22/24 (91.7%) samples the protein was undetectable (mean, 0.04 µg/cm2). ATP test was above the cutoff (200 relative light units [RLU]) in 17/24 (70.8%) samples (mean, 498 RLU). After the second cleaning, 11/17 (64.7%) gastroscopes still failed the ATP test (mean, 321.2 RLU). The mean time spent to perform manual cleaning and ATP tests was 16 and 8 minutes, respectively. Hence, each test increased the length of time for cleaning plus testing cleanliness by 50%. CONCLUSION: Further studies regarding the optimal cutoff for ATP tests are needed. ATP tests for cleaning monitoring are easy to perform and provide immediate feedback to the team. However, the increased workload needs to be considered.

Assessing residual contamination and damage inside flexible endoscopes over time.

Researchers evaluated flexible endoscope damage and contamination levels at baseline and 2 months later. Postcleaning test results exceeded benchmarks for all gastroscopes and no colonoscopes. Microbial growth was found in samples from 47% of fully reprocessed endoscopes at baseline and 60% at follow-up. Borescope examinations identified scratches, discoloration, debris, and fluid inside endoscopes. Irregularities changed over time. Study evaluations allowed damaged and contaminated endoscopes to be identified and re-reprocessed or sent for repairs.

Persistent residual contamination in endoscope channels; a fluorescence epimicroscopy study.

BACKGROUND AND STUDY AIMS: The increasing demand for endoscopic procedures poses new contamination challenges, given developing antimicrobial resistance worldwide and potential viral or prion diseases in populations at risk. We examined working channels from reusable luminal endoscopes used in recent years. METHODS: Very sensitive fluorescence epimicroscopy was used to examine working channels from 6 decommissioned and 6 factory-new channels, as received, or following spiking and washing in the laboratory. RESULTS: After a single contamination and wash test cycle, new channels retained approximately 75 pg/mm(2) of proteins; through 7 subsequent cycles residual proteins fluctuated between 25 and 75 pg/mm(2). Decommissioned channels harbored 1 - 4 µg of proteins each, except in one gastroscope (33 µg), including up to 2 % amyloid proteins except in one gastroscope and one sigmoidoscope (with over 80 %); lumens showed wearing with established abraded biofilms in 3 cases. After spiking with scrapie-infected blood components and washing, residual protein levels in new channels varied following standard (17.23 pg/mm(2)), duplicated (2.39 pg/mm(2)) or extended (11.3 pg/mm(2)) washing; no changes were measured among the long-established contamination in old channels. CONCLUSIONS: Our observations suggest that wear effects in endoscope lumens may contribute to the adsorption of proteins, thus facilitating retention and survival of bacteria. As demonstrated by recent outbreaks worldwide despite recommended reprocessing, the development of antimicrobial-resistant bacterial strains, and the estimated prevalence of variant Creutzfeldt-Jakob disease (vCJD) in the UK particularly, combined with increasing demand for endoscopic procedures, call for sustained precautions and improved methods for the reprocessing of nonautoclavable, reusable surgical instruments.

Practical toolkit for monitoring endoscope reprocessing effectiveness: Identification of viable bacteria on gastroscopes, colonoscopes, and bronchoscopes.

BACKGROUND: Experts have recommended microbiologic surveillance by external reference laboratories for certain flexible endoscopes. There is currently insufficient evidence on the feasibility and utility of cultures. Researchers evaluated a preassembled toolkit for collecting and processing samples from endoscopes. METHODS: A pilot study was performed in a large academic medical center. A toolkit was used to aseptically sample biopsy ports and suction/biopsy channels of 5 gastroscopes, 5 colonoscopes, and 5 bronchoscopes after full reprocessing. Blinded specimens were packaged and transported on icepacks to a reference laboratory that used standard methodologies for microbial cultures. RESULTS: The laboratory detected bacteria in samples from 60% of patient-ready endoscopes, including gram-positive and gram-negative species. Viable microbes (<10 CFU) were recovered from 2 gastroscopes, 3 colonoscopes, and 4 bronchoscopes. Stenotrophomonas maltophilia and Delftia acidovorans were recovered from all 3 endoscope types. Subsequent environmental testing detected S maltophilia in the reprocessing rinse water. CONCLUSIONS: A preassembled toolkit facilitated the aseptic collection of samples for culturing by a reference laboratory that detected viable microbes on fully reprocessed endoscopes. Speciation allowed identification of potential pathogens and a possible common contamination source, demonstrating that microbial cultures may have value even when colony counts are low.

Persistent contamination on colonoscopes and gastroscopes detected by biologic cultures and rapid indicators despite reprocessing performed in accordance with guidelines.

BACKGROUND: Pathogens have been transmitted via flexible endoscopes that were reportedly reprocessed in accordance with guidelines. METHODS: Researchers observed reprocessing activities to ensure guideline compliance in a large gastrointestinal endoscopy unit. Contamination was assessed immediately after bedside cleaning, manual cleaning, high-level disinfection, and overnight storage via visual inspection, aerobic cultures, and tests for adenosine triphosphate (ATP), protein, carbohydrate, and hemoglobin. RESULTS: All colonoscopes and gastroscopes were reprocessed in accordance with guidelines during the study. Researchers collected and tested samples during 60 encounters with 15 endoscopes. Viable microbes were recovered from bedside-cleaned (92%), manually cleaned (46%), high-level disinfected (64%), and stored (9%) endoscopes. Rapid indicator tests detected contamination (protein, carbohydrate, hemoglobin, or ATP) above benchmarks on bedside-cleaned (100%), manually cleaned (92%), high-level disinfected (73%), and stored (82%) endoscopes. Visible residue was never observed on endoscopes, but it was often seen on materials used to sample endoscopes. Seven endoscopes underwent additional reprocessing in response to positive rapid indicators. Control endoscope channels were free of biologic residue and viable microbes. CONCLUSION: Despite reprocessing in accordance with US guidelines, viable microbes and biologic debris persisted on clinically used gastrointestinal endoscopes, suggesting current reprocessing guidelines are not sufficient to ensure successful decontamination.

Safety and efficacy of a novel disposable sheathed gastroscopic system in clinical practice.

BACKGROUND AND AIM: Endoscopic examinations carry a potential risk of cross-infection, and the traditional reprocessing method is time consuming. We evaluated the safety and efficacy of a novel disposable sheathed gastroscope system in clinical practice in comparison with the conventional gastroscope. METHODS: There were two phases in the study. In phase 1, 20 patients with hepatitis B were randomized into two groups: the sheathed group was examined with the novel disposable sheathed gastroscope (n = 10) and the conventional group with the conventional gastroscope (n = 10). Microbiologic tests were performed on each endoscope afterwards. In the second phase, 1120 patients were randomized again into the same two groups with 568 and 552 patients in the sheathed group and the conventional group, respectively. The time duration of the endoscopic procedure and reprocessing were measured. The pathology detection rate of endoscopic examinations, the patients' subjective feelings, and problems occurred during procedures were also recorded. RESULTS: The total instrument turn-around time in the phase 2 sheathed group (9.9 ± 1.3 min) was significantly shorter than the conventional group (39.0 ± 1.4 min, P = 0.000). The mean procedural time was slightly longer in the sheathed group than in the conventional group (4.9 ± 1.4 vs 4.1 ± 1.3 min, P = 0.000). However, the duration of endoscopic reprocessing was much shorter (4.9 ± 0.2 vs 35 ± 0.2 min, P = 0.000). No significant differences were observed in patient discomfort, optical clarity, or pathology detection rate. There were no complications in either group, and no microbial contamination was detected in phase 1 of the study. CONCLUSIONS: Compared with the conventional gastroscope, the novel disposable sheathed gastroendoscope is safe and more efficient in clinical practice.

Effectiveness of flexible gastrointestinal endoscope reprocessing.

The practice of reprocessing endoscopes and its effectiveness was evaluated in 37 services. Contamination of at least 1 endoscope could be identified in 34 (91.6%) of 37 services. Bacteria, fungi, and/or mycobacteria were isolated from 84.6% (33/39) of the colonoscopes (110-32,000 colony-forming units [CFUs]/mL) and from 80.6% (50/62) of the gastroscopes (100-33,000 CFUs/mL). Not all services followed recommended guidelines. Therefore, patients who underwent gastrointestinal endoscopies were exposed to diverse pathogens.

Oral chlorhexidine and microbial contamination during endoscopy: possible implications for transgastric surgery. A randomized, clinical trial.

BACKGROUND: One of the biggest concerns associated with transgastric surgery is contamination and risk of intra-abdominal infection with microbes introduced from the access route. The purpose of this study was to evaluate the effect of oral decontamination with chlorhexidine on microbial contamination of the endoscope. METHODS: In a prospective, randomized, single-blinded, clinical trial the effect of chlorhexidine mouth rinse was evaluated. As a surrogate for the risk of intra-abdominal contamination during transgastric surgery, microbial contamination of the endoscope during upper endoscopy was examined. Patients referred to upper endoscopy were assessed for eligibility and randomized to either chlorhexidine or no mouth rinse. Culture samples were collected from gastric aspirates and endoscopes. The primary outcome measure was colony forming units (CFU) in the endoscope samples. Secondary outcome measures were species specific effect of chlorhexidine on micro-organisms with abscess forming capabilities and the effect of proton pump inhibitor (PPI) treatment on CFU. RESULTS: Chlorhexidine mouth rinse resulted in a significant reduction of CFU in the endoscope samples (p = 0.001). There was no species specific effect and micro-organisms with abscess forming capabilities were equally present. PPI treatment was associated with significantly higher CFU counts in both the gastric (p = 0.004) and endoscope samples (p = 0.049). CONCLUSIONS: Chlorhexidine mouth rinse was effective in reducing microbial contamination of the endoscope, but micro-organisms with abscess forming capabilities were still present. PPI treatment significantly increased CFU and should be discontinued before transgastric surgery.

Gastroscopy-associated transmission of extended-spectrum beta-lactamase-producing Pseudomonas aeruginosa.

An unusual multi-drug-resistant Pseudomonas aeruginosa (MDR-PA) was isolated in four patients whilst hospitalized in a French teaching hospital between May and August 2011. All four patients had undergone an oesophago-gastro-duodenoscopy with the same gastroscope over a five-month period. This endoscope was associated with a culture positive for the MDR-PA. Observations of endoscope reprocessing identified deviations from the agreed processes: insufficient initial cleaning, shortening of the immersion time and brushing time, insufficient channel flushing, and inadequate drying prior to storage. Since withdrawing the gastroscope and institution of strict adherence to the agreed processes, no other MDR-PA cases have been isolated.

Swab culture monitoring of automated endoscope reprocessors after high-level disinfection.

AIM: To conduct a bacterial culture study for monitoring decontamination of automated endoscope reprocessors (AERs) after high-level disinfection (HLD). METHODS: From February 2006 to January 2011, authors conducted randomized consecutive sampling each month for 7 AERs. Authors collected a total of 420 swab cultures, including 300 cultures from 5 gastroscope AERs, and 120 cultures from 2 colonoscope AERs. Swab cultures were obtained from the residual water from the AERs after a full reprocessing cycle. Samples were cultured to test for aerobic bacteria, anaerobic bacteria, and mycobacterium tuberculosis. RESULTS: The positive culture rate of the AERs was 2.0% (6/300) for gastroscope AERs and 0.8% (1/120) for colonoscope AERs. All the positive cultures, including 6 from gastroscope and 1 from colonoscope AERs, showed monofloral colonization. Of the gastroscope AER samples, 50% (3/6) were colonized by aerobic bacterial and 50% (3/6) by fungal contaminations. CONCLUSION: A full reprocessing cycle of an AER with HLD is adequate for disinfection of the machine. Swab culture is a useful method for monitoring AER decontamination after each reprocessing cycle. Fungal contamination of AERs after reprocessing should also be kept in mind.

Transgastric instrumentation and bacterial contamination of the peritoneal cavity.

INTRODUCTION: Natural orifice transluminal endoscopic surgery (NOTES) is a rapidly evolving technique providing access to the peritoneum utilizing an endoscope via a natural orifice. One of the most significant requirements of this technique is the need to minimize the risk of clinically significant peritoneal contamination. We report the bacterial load and contamination of the peritoneal cavity in patients requiring a gastrotomy Roux-en-Y gastric bypass (LSRYGB). METHODS: We prospectively studied 50 patients undergoing a gastrotomy with creation of a gastrojejunostomy during LSRYGB. We recorded the patient's proton-pump inhibitor (PPI) utilization preoperatively and sampled gastric contents without lavage. We also sampled peritoneal fluid prior to and after gastrotomy, noting the length of time the gastrotomy was open to the peritoneum. Each of the three samples was sent for bacterial colony counts, and culture with identification of species. RESULTS: Fifty patients underwent LSRYGB with a mean operative time of 93 min. The gastrotomy was open to the peritoneal cavity for an average of 18 min. Seventeen of 50 patients were on PPIs preoperatively, resulting in a significant difference in postgastrostomy peritoneal bacterial counts. The average number of colony-forming units (CFU) of the gastric aspirate was 22,303 CFU/ml. Peritoneal aspirates obtained for examination prior to creation of a gastrotomy showed no CFUs in 44 of 50 patients. Peritoneal sampling after gastrotomy showed contamination of the abdomen with an average of 1102 CFU/ml. There was no correlation between the bacterial load in the stomach and peritoneal load after gastrotomy. No infectious complications or leaks developed. One complication of rhabdomyolysis in a patient with no peritoneal bacterial contamination developed. CONCLUSIONS: Transgastric instrumentation does contaminate the abdominal cavity but pathogens are clinically insignificant due to species or bacterial load. Patients on PPIs do have an increased bacterial load in the gastric aspirate, with no clinical significant infection.

Results of gastroscope bacterial decontamination by enzymatic detergent compared to chlorhexidine.

AIM: To compare the efficacy of enzymatic detergent with chlorhexidine for gastroscope bacterial decontamination. METHODS: A prospective randomized controlled study was undertaken to evaluate the ability of these 2 agents to achieve high level disinfection in a gastroscope. A total of 260 samples were collected from 5 different gastroscopes. Manual cleaning was done for 10 min with these 2 agents separately (n = 130 each). Then all specimens underwent 2% glutaraldehyde soaking for 20 min. After 70% alcohol was rinsed, sterile normal saline was flushed into each gastroscope channel and 40 mL of sample was collected. The sample was sent for aerobic bacterial culture after membrane was filtered. A colony count greater than 200 cfu/mL was considered significant. RESULTS: The positive culture rate was 4.6% in the enzymatic detergent arm and 3.1% in the chlorhexidine arm. Pseudomonas species were the main organism detected from both groups (60%). Multiple organisms were found from 4 specimens (enzymatic detergent arm = 1, chlorhexidine arm = 3). CONCLUSION: The contamination rate of both types of cleaning solution is equivalent.

[Microbiological evaluation of gastroscope decontamination by electrolysed acid water (Clentop WM-1)]. / Análise microbiológica de gastroscópios descontaminados em aparelho Cleantop WM-1 por uso de água eletrolítica ácida.

BACKGROUND: The manual disinfection of endoscopes with glutharaldeyde is widely employed. The great routine in gastroenteroscopy services, low number of equipment and the lack of technical knowledge about the decontamination processes are factors that stimulate the inadequate endoscope disinfection, intensifying the risk of transmission of microorganisms. The electrolysed acid water has been effective in the inactivation and destruction of microorganisms. AIM: The purpose of this investigation was to verify the microbicidal efficiency of electrolyzed acid water (Cleantop WM-1) to decontaminate gastroscopes after their using in patients. MATERIAL AND METHODS: Samples from biopsy channel of flexible endoscopes collected after patient use (n = 20) and after disinfection (n = 20) were cultivated in tryptic soy agar, MacConkey agar and Sabouraud dextrose agar. RESULTS: Seventeen of the 20 samples collected after patients examination yielded gram-negative bacilli, gram-positive coccus and yeast cells in contamination of 3 to 5 log10 ufc/mL. Microbial growth was not verified in samples collected after the decontamination process. Conclusion - In this preliminary study, the mechanical disinfection carried through the Cleantop device with electrolyzed acid water showed satisfactory results for the elimination of microorganisms and time optimization in the reprocessing of gastroscopes.

Análise microbiológica de gastroscópios descontaminados em aparelho Cleantop WM-1 por uso de água eletrolítica ácida / Microbiological evaluation of gastroscope decontamination by electrolysed acid water (Clentop WM-1)

RACIONAL: O método com utilização manual de glutaraldeído é amplamente empregado para desinfecção de endoscópios. A elevada rotina nos serviços de gastroscopia, pequena quantidade de equipamentos e a falta de conhecimento técnico sobre os processos de descontaminação contribuem para desinfecção inadequada dos endoscópios, intensificando o risco de transmissão de microrganismos. A água eletrolítica ácida tem apresentado eficácia na inativação e destruição de microrganismos e vem sendo usada na descontaminação de endoscópios. OBJETIVO: Verificar a eficiência microbicida da água eletrolítica ácida, produzida pelo aparelho Cleantop WM-1, em 20 gastroscópios contaminados após uso em pacientes. MATERIAL E MÉTODOS: Amostras coletadas do canal de biopsia dos endoscópios, após uso em pacientes (n = 20) e depois da desinfecção (n = 20), foram cultivadas em ágar tripticaseína de soja, MacConkey e Sabouraud dextrose. RESULTADOS: Dezessete das 20 amostras coletadas após o uso do aparelho em pacientes revelaram a presença de bacilos gram-negativos, cocos gram-positivos e leveduras em taxas de 103 a 105 ufc/mL. Nenhuma amostra, das 20 coletadas após a descontaminação, apresentou contaminação microbiana. CONCLUSÃO: Nesse estudo preliminar, a desinfecção mecânica realizada pelo aparelho Cleantop com água eletrolítica ácida revelou resultados satisfatórios pela eliminação de microrganismos e otimização no tempo de processamento dos gastroscópios.

Helicobacter pylori DNA in dental plaques, gastroscopy, and dental devices.

The role of dental plaque in the transmission of Helicobacter pylori (Hp) is unclear due to variability in the detection rates and techniques used. We used nested PCR to estimate the incidence of Hp in dental plaques of 24 dental hygienists. We found an unexpectedly high incidence (50%) of Hp DNA in dental plaques using sterilized dental probes. Additional treatment of sonication and SDS wash prior to sterilization of dental probes reduced the incidence to 13%. We used the treated probes to assess Hp presence in plaque samples of 47 patients visiting the dental clinic for teeth cleaning. Hp DNA was detected in 24% of cases. Since these data may reflect instrument contamination, we tested dental probes, endoscopes, and endoscopy forceps and found that 12.5-37.5% of them were contaminated. Consequently, dental plaques may be a candidate reservoir for Hp, medical equipment may contribute to Hp transmission, and sample collection techniques can bias the true prevalence of Hp in a population.

Gastroscope processing in washer-disinfectors at three different temperatures.

Endoscopes are processed chemo-thermally at approximately 56 degrees C in washer-disinfectors in Germany. In this study we investigated the processing of gastroscopes by an endoscope washer-disinfector at different temperatures. A total of 87 gastroscopes were tested hygienically and microbiologically before manual cleaning (after patient use), as well as after manual cleaning and after endoscope washer-disinfector processing at running temperatures of 43, 51 and 56 degrees C. In all tests the suction/biopsy channels of the gastroscopes were flushed with 50 mL sterile solution throughout their full length, from the proximal to the distal ends. The rinse solutions were plated on to various culture media. Also, in order to detect low bacterial counts, 3x10 mL rinse solution was membrane filtrated. The German guideline level for total bacterial counts, applicable since 2002, was exceeded at all temperatures tested (159 cfu/mL at 43 degrees C, <60 cfu/mL at 51 degrees C, and 8 cfu/mL at 56 degrees C). A temperature increase from 43 to 51 degrees C resulted in a highly significant reduction of the residual contamination by aerobic bacteria (P<0.001, Mann-Whitney U Test), Gram-negative bacilli (P<0.001), and pseudomonads (P=0.002). A further temperature increase from 51 to 56 degrees C resulted in a further highly significant drop in residual contamination by aerobic bacteria (P=0.021) and pseudomonads (P=0.036). The aim of the user-minimizing material damage to endoscopes or prolonging their product life-cannot be achieved through lowering the processing temperature without putting patients at risk. In order to ensure adequate processing, endoscope washer-disinfectors should meet the requirements of current draft standards.