No relation between adenosine triphosphate after manual cleaning and presence of microorganisms on endoscopes after automated high-level disinfection

Background and study aims  Adenosine triphosphate (ATP) tests are increasingly used to detect biological material; however, their reliability to detect bacterial contamination in endoscopes is not proven. We investigated the predictive value of ATP tests after manual cleaning for presence or absence of microorganisms as shown by culture after automated high-level disinfection (HLD) in duodenoscopes and linear echoendoscopes (DLEs). Patients and methods  After manual cleaning, ATP tests were performed on swab samples taken from the detachable cap and forceps elevator, and on flush samples of the DLE working channels. These results were compared to the growth of any microorganisms in cultures acquired after automated HLD. ATP tests with > 200 relative light units (RLU) were considered positive. Receiver operator characteristic (ROC) curves were used to compare the RLU levels with microbial presence in cultures. Results  In total, 903 procedures were performed involving 26 distinct DLEs. Depending on sample site, 20.8 % (cap) to 63.8 % (channel brush) of the ATP negative samples were accompanied by positive post-HLD cultures. 54.4 % of the cap samples with a positive culture (growth of any kind of microorganism) and 91.8 % of the channel samples with a positive culture had a negative ATP test after manual cleaning. ROC curves per sample site, DLE type and microorganism type all had area under the curves below 0.6. Conclusions  In our study, ATP tests performed after manual cleaning could not predict presence or absence of microorganisms after automated HLD as shown by culture. More than half of the positive cultures were preceded by a negative ATP test.

ATP Bioluminescence for Assessing the Efficacy of the Manual Cleaning Procedure during the Reprocessing of Reusable Surgical Instruments

Achieving sterilization by adopting proper practices is essential to ensure that surgical instruments do not transmit microorganisms to patients. As the effectiveness of sterilization mandates effective cleaning, it is necessary to verify the success of cleaning procedures. In this study, we used the adenosine triphosphate (ATP) bioluminescence method for assessing the efficacy of the manual cleaning procedure during the reprocessing of reusable surgical instruments. The ATP bioluminescence assay was performed on 140 surgical instruments of 12 different types, both before being cleaned (baseline) and after each of the cleaning procedures (i.e., decontamination, manual washing, drying, and visual inspection). For each instrument, two swabs were used as follows: one to sample the entire surface (test point 1) and the other to sample the most difficult part of the surface to clean (test point 2). Overall, for each type of instrument, there was a decrease in contamination ranging from 99.6 to >99.9% (log reduction from 2.40 to 3.76). Thus, in order to standardize the assessment of cleanliness, it may be useful to introduce the bioluminescence method into the daily routine or, at least, at regular time intervals as a complementary check combined with visual inspection. This would allow real-time verification of the achievement of an adequate level of cleanliness.

Microbiological Surveillance of Endoscopes in a Southern Italian Transplantation Hospital: A Retrospective Study from 2016 to 2019

Endoscopes are medical instruments that are used routinely in health structures. Due to their invasive nature and contact with many patients, they may cause hospital-acquired infections if not disinfected correctly. To ensure a high-level disinfection procedure or reprocessing, since the methods currently adopted in our institute are adequate, we evaluated retrospectively the presence of microorganisms in our endoscopes after reprocessing. Microbiological surveillance was performed from January 2016 to December 2019 in the instruments in use in our endoscopic room after reprocessing. In total, 35 endoscopes (3 duodenoscopes, 3 echoendoscopes, 12 bronchoscopes, 5 colonoscopes, and 12 gastroscopes) were evaluated for the presence of microorganisms, including multidrug-resistant pathogens and indicator microorganisms (IMOs). Our procedures were in agreement with an internal protocol based on Italian, international, and the Center for Disease Control and Prevention (CDC) recommendations. Of a total of 811 samples, 799 (98.5%) complied with the regulatory guidelines, while 9 (1.1%) were positive for IMOs, and 3 (0.4%) displayed more than 10 colony-forming units (CFU) of environmental and commensal pathogens. Our results show that the internal reprocessing protocol is very efficient, leading to a very low number of observed contaminations, and it could be easily implemented by other health facilities that face a huge number of hospital-acquired infections due to incorrectly disinfected endoscopes.

Adenosine Triphosphate-Bioluminescence Technology as an Adjunct Tool to Validate Cleanliness of Surgical Instruments

Perioperative and sterile processing department personnel commonly use visual inspection to validate surgical instrument cleanliness. This validation process does not detect microbes (eg, bacteria, viruses) and the resultant inadequately decontaminated instruments can put patients at risk for developing surgical site infections. Sterile processing department personnel should use a rapid, straightforward method to validate surgical instrument cleanliness objectively. During a quality improvement project at a military treatment facility, staff members found that adenosine triphosphate (ATP)-based technology was a viable and affordable solution for detecting bioburden and validating cleaning practices. The project design compared manually and mechanically cleaned cannulated instruments (59 of each) and identified 16 contaminated instruments, 14 of which had been manually cleaned. The contamination rate after mechanical cleaning was significantly lower (P = .0022) compared with manual cleaning. As a result of this quality improvement project, this facility fully implemented the technology to validate instrument cleaning.

A newly designed duodenoscope with detachable distal cap significantly reduces organic residue contamination after reprocessing

BACKGROUND

A newly designed duodenoscope with detachable distal cap may reduce bacterial contamination by allowing better access to the elevator. We compared bacterial contamination and organic residue evaluated by rapid adenosine triphosphate (ATP) test and culture from duodenoscopes with detachable vs. fixed distal caps after high-level disinfection (HLD).

METHODS

During December 2018-April 2019, 108 used newly designed duodenoscopes were enrolled. In group A (n = 54), the distal cap of the duodenoscope was detached before manual cleaning. In group B (n = 54), the distal cap was not detached. After HLD, samples were collected from the elevator, submitted for culture, and evaluated using the ATP test, using the cutoff value of 40 relative light units (RLUs).

RESULTS

After HLD, the proportion of potential bacterial contamination and organic residue in group A was significantly lower than in group B (37.0 % vs. 75.9 %; P  < 0.001; relative risk 0.49, 95 % confidence interval 0.33-0.71), and also confirmed by median ATP values (45.2 vs. 141.0 RLU; P  < 0.001). In group B, one sample culture was positive for nonpathogenic bacteria. Pathogenic bacteria were not found in any culture from either group.

CONCLUSIONS

The detachable distal cap was more effective at eliminating bacterial contamination and reducing organic residue than a fixed cap. Nonpathogenic bacteria were detected in the fixed cap group after reprocessing. The ATP test with 40 RLU cutoff is a practical method to ensure the cleanliness of duodenoscope reprocessing without the need to wait for bacterial culture results.

Performance characteristics and optimal cut-off value of triple adenylate nucleotides test versus adenosine triphosphate test as point-of-care testing for predicting inadequacy of duodenoscope reprocessing

BACKGROUND

Adenosine triphosphate (ATP) test based on one nucleotide has been applied as point-of-care testing (POCT) for bacterial contamination in the medical and food industries. Hypothetically, testing three adenylate nucleotides (A3) may provide better detection of duodenoscope bacterial contamination than ATP test.

AIM

To evaluate performance characteristics and optimal cut-off value of A3 and ATP tests in predicting bacterial contamination of duodenoscopes.

METHODS

Four hundred duodenoscope samples obtained after 100 endoscopic retrograde cholangiopancreatography procedures were randomized into group A (A3 test) or B (ATP test). Samples were collected from the elevator at the four-step cleaning process of duodenoscope. We defined the new cut-off value of the test for reaching 100% negative predictive value (NPV) from our receiver operating characteristic (ROC).

FINDINGS

Using the cultures from the four-step cleaning process as the reference, the areas under ROC (AUROC) were 0.83 and 0.84 for group A (N = 200) and group B (N = 200), respectively. Using the cultures from post-high-level disinfection (HLD) as the reference, the AUROC were 0.35 and 0.74 for group A (N = 50) and group B (N = 50), respectively. We investigated ATP as a POCT after HLD with a new cut-off value of 40 RLU. However, this threshold did not allow detection of low numbers of bacteria.

CONCLUSION

A3 and ATP tests provide good performances in predicting bacterial contamination of duodenoscopes for the four-step cleaning process. The ATP <40 RLU is helpful as a POCT after HLD; however, the limitation of this cut-off value is its inability to detect low numbers of bacteria.

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.

The validity of adenosine triphosphate measurement in detecting endoscope contamination

BACKGROUND

Endoscopic procedures are vital to gastrointestinal disease diagnosis and management, but risk infection transmission. In Australia, endoscopes undergo monthly-to-quarterly microbiological testing, to prevent patient infection. Endoscopes are used more frequently, meaning contamination may not be detected by this surveillance before infection transmission occurs.

AIM

To evaluate the use of adenosine triphosphate (ATP) measurement, alongside standard microbiological cultures, in detecting endoscope contamination before high-level disinfection. Using these results, we also aimed to confirm the efficacy of manual cleaning in reducing levels of ATP and cfu/mL.

METHODS

Seventeen in-clinical-use gastroscopes and 24 in-clinical-use colonoscopes from the Liverpool Hospital Endoscopy unit were sampled across three separate cleaning stages before high-level disinfection. Colony counts and ATP measurements were then performed on these samples.

FINDINGS

The correlation between the cfu/mL and RLU of samples collected from colonoscopes was 0.497 (95% confidence interval: 0.28-0.66; P < 0.0001). The correlation between cfu/mL and RLU for samples collected from gastroscopes was 0.377 (0.08-0.61; P = 0.0138). RLU and cfu/mL values were shown to fall significantly (P < 0.005) following precleaning and manual cleaning.

CONCLUSION

There was a significant correlation between ATP and cfu/mL measured from samples collected before high-level disinfection. Precleaning and manual cleaning were shown to reduce ATP and microbiological load significantly. ATP measurement can be performed within minutes with little training and produces results that are easy to interpret. These findings warrant further research on the utility of ATP measurement as a screening tool for detecting endoscope contamination after high-level disinfection.

A systematic review of adenosine triphosphate as a surrogate for bacterial contamination of duodenoscopes used for endoscopic retrograde cholangiopancreatography

BACKGROUND

Bacterial culture is the accepted standard to measure the adequacy of high-level disinfection (HLD) of duodenoscopes. Adenosine triphosphate (ATP) bioluminescence assays have been suggested as an alternative method of evaluating the quality of reprocessing. We systematically reviewed published research describing the correlation between ATP and bacterial cultures.

METHODS

The primary outcome was the correlation or concordance between concomitantly sampled ATP and bacterial contamination obtained from the instrument channel and/or elevator mechanism of the duodenoscope. A secondary outcome included the reduction in ATP measurements between paired samples before and after stages of duodenoscope reprocessing.

RESULTS

Ten studies were included in the analysis. Four studies reported the relationship between concomitantly sampled ATP and cultures. Three studies reported receiver operating characteristic curves (1 study additionally reported a Wilcoxon rank sum test), and 1 study reported Spearman correlation coefficients and paired dichotomous measurements of ATP and bacterial contamination. All analyses suggested a poor relationship between the 2 measures. Studies measuring ATP before and after manual cleaning and before and after HLD reported a reduction in ATP after the reprocessing stage.

CONCLUSION

Current research does not support the direct substitution of ATP for bacterial culture surveillance of duodenoscopes. Serial ATP measurement may be a useful tool to evaluate the adequacy of manual cleaning and for training of endoscopic reprocessing staff.

Adenosine triphosphate bioluminescence to validate decontamination of endoscopes

The reports of outbreaks involving carbapenemase-resistant Enterobacteriaceae (CRE) associated with gastrointestinal endoscopy prompted a review and study of a novel method of assessing cleaning. This study assessed adenosine triphosphate (ATP) bioluminescence to demonstrate cleanliness prior to endoscopy. ATP testing was compared with microbiological monitoring for 127 endoscopes. Samples were taken after cleaning, reprocessing and storage, but immediately before the endoscopy procedure. We recommend implementing ATP testing prior to endoscopy procedures as an alternative to microbiological testing at periodic intervals. ATP testing provides a convenient assessment of endoscopy hygiene to demonstrate safety and quality assurance.

Adenosine Triphosphate Quantification Correlates Poorly with Microbial Contamination of Duodenoscopes

OBJECTIVE The aim of this study was to quantify the correlation between adenosine triphosphate (ATP) measurements and bacterial cultures from duodenoscopes for evaluation of contamination following high-level disinfection. DESIGN Duodenoscopes used for any intended endoscopic retrograde cholangiopancreatography (ERCP) procedure were included. Microbiologic and ATP data were collected concomitantly and in the same manner from ERCP duodenoscopes. SETTING A high-volume endoscopy unit at a tertiary referral acute-care facility. METHODS Duodenoscopes were sampled for ATP and bacterial contamination in a contemporaneous and highly standardized fashion using a "flush-brush-flush" method for the working channel (WC) and a dry flocked swab for the elevator mechanism (EM). Specimens were processed for any aerobic bacterial growth (colony-forming units, CFU). Growth of CFU>0 and ATP relative light unit (RLU)>0 was considered a contaminated result. Frequency of discord between among WC and EM measurements were calculated using 2×2 contingency tables. The Spearman correlation coefficient was used to calculate the relatedness of bacterial contamination and ATP as continuous measurements. RESULTS The Spearman correlation coefficient did not demonstrate significant relatedness between ATP and CFU for either a WC or EM site. Among 390 duodenoscope sampling events, ATP and CFU assessments of contamination were discordant in 82 of 390 WC measurements (21%) and 331 of 390 of EM measurements (84.9%). The EM was frequently and markedly positive by ATP measurement. CONCLUSION ATP measurements correlate poorly with a microbiologic standard assessing duodenoscope contamination, particularly for EM sampling. ATP may reflect biological material other than nonviable aerobic bacteria and may not serve as an adequate marker of bacterial contamination. Infect Control Hosp Epidemiol 2017;38:678-684.

Usefulness of Adenosinetriphosphate Bioluminescence Assay (ATPmetry) for Monitoring the Reprocessing of Endoscopes

OBJECTIVE

To assess the diagnostic value of an adenosinetriphosphate bioluminescence assay (ATPmetry) to monitor the effectiveness of the reprocessing of endoscopes compared with microbiologic sampling.

DESIGN

Diagnostic study.

SETTING

A 2,200-bed teaching hospital performing 5,000 to 6,000 endoscopic procedures annually.

INCLUSION CRITERIA

All samples from bronchial or gastrointestinal endoscopes whatever the context.

METHODS

Samples for microbiologic analysis and ATPmetry measurements were taken when each endoscope was inspected following reprocessing. Sampling was performed by flushing each endoscope with 300 mL Neutralizing Pharmacopeia Diluent thiosulfate rinsing solution divided equally between the endoscope channels. For each endoscope a series of 3 ATPmetry measurements were made on a vial containing the first jet from each channel and a second series on the whole sample.

RESULTS

Of 165 samples from endoscopes, 11 exceeded the acceptability threshold of 25 colony-forming units/endoscope. In the first jet collected, the median (interquartile range) level of ATPmetry was 30.5 (15.3–37.7) relative light units (RLU) for samples with 25 or fewer colony-forming units compared with 37.0 (34.7–39.3) RLU for samples with more than 25 colony-forming units (P=.008). For the whole sample, the median (interquartile range) level of ATPmetry was 24.8 (14.3–36.3) RLU and 36.3 (36.0–38.3) RLU (P=.006), respectively. After adjusting on the batch of cleansing solution used, no difference in ATPmetry values was found between microbiologically acceptable and unacceptable samples.

CONCLUSION

ATPmetry cannot be used as an alternative or complementary approach to microbiologic tests for monitoring the reprocessing of endoscopes in France

Infect. Control Hosp. Epidemiol. 2015;36(12):1437–1443