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.

Assessment of postmanual cleaning adenosine triphosphate tests to prevent the use of contaminated duodenoscopes and linear echoendoscopes: the DETECT study.

BACKGROUND AND AIMS: We investigated whether the use of postmanual cleaning adenosine triphosphate (ATP) tests lowers the number of duodenoscopes and linear echoendoscopes (DLEs) contaminated with gut flora. METHODS: In this single-center before-and-after study, DLEs were ATP tested after cleaning. During the control period, participants were blinded to ATP results: ATP-positive DLEs were not recleaned. During the intervention period, ATP-positive DLEs were recleaned. DLEs underwent microbiologic sampling after high-level disinfection (HLD) with participants blinded to culture results. RESULTS: Using 15 endoscopes of 5 different DLE types, we included 909 procedures (52% duodenoscopes, 48% linear echoendoscopes). During the intervention period, the absolute rate of contamination with gut flora was higher (16% vs 21%). The main analysis showed that contamination was less likely to occur in the intervention period (odds ratio, .32; 95% credible interval [CI], .12-.85). A secondary analysis showed that this effect was based on 1 particular duodenoscope type (estimated probability, 39% [95% CI, 18%-64%] vs 9% [95% CI, 2%-21%]), whereas no effect was seen in the other 4 DLE types. In detail, of the 4 duodenoscopes of this type, 2 had lower contamination rates (69% vs 39% and 36% vs 10%). During the control period, both these duodenoscopes had multiple episodes with ongoing contamination with the same microorganism that ended weeks before the start of the intervention period (ie, they were not terminated by ATP testing). CONCLUSIONS: Postmanual cleaning ATP tests do not reduce post-HLD gut flora contamination rates of DLEs. Hence, postcleaning ATP tests are not suited as a means for quality control of endoscope reprocessing.

Investigation of possible transmission of a susceptible microorganism through a contaminated duodenoscope; a case report.

BACKGROUND: Despite compliance to extensive reprocessing protocols, duodenoscopes have been linked to outbreaks of susceptible and multi-drug resistant organisms (MDRO) due to persistent duodenoscope contamination. Duodenoscope-associated infections (DAIs) based on transmission of susceptible microorganisms are likely to be underreported due to detection bias. CASE PRESENTATION: We describe the retrospective detection of a DAI case caused by a susceptible microorganism which at the time of clinical infection was not recognized as such. During 2017 and 2018, duodenoscopes were cultured on a daily basis due to research activities. While analyzing this data, it was found that a duodenoscope had been contaminated with Enterobacter cloacae complex over a period of 3 months. We checked whether patients treated with this duodenoscope had developed infections and found one patient with an E. cloacae cholangitis 3 months after the ERCP (Endoscopic retrograde cholangiopancreaticography) procedure. The isolates on the duodenoscope and in the patients' blood culture were indistinguishable by amplified fragment length polymorphism (AFLP). By classical multi-locus sequence typing (MLST), both strains were of the same (but novel) sequence type. Application of whole genome MLST showed 93 (out of 3757) allelic differences. CONCLUSION: This case report describes a plausible link between a contaminated duodenoscope and a patient infection with E. cloacae. Transmission of susceptible E. cloacae was highly suspected from AFLP and MLST results; by WGS, 93 allelic differences were found which proves closely related strains. This report shows that DAIs by susceptible microorganisms can be easily missed and therefore its true prevalence remains underscored.

Nationwide risk analysis of duodenoscope and linear echoendoscope contamination.

BACKGROUND AND AIMS: Contaminated duodenoscopes and linear echoendoscopes (DLEs) pose a risk for infectious outbreaks. To identify DLEs and reprocessing risk factors, we combined the data from the previously published nationwide cross-sectional PROCESS 1 study (Prevalence of contamination of complex endoscopes in the Netherlands) with the follow-up PROCESS 2 study. METHODS: We invited all 74 Dutch DLE centers to sample ≥2 duodenoscopes during PROCESS 1, and all duodenoscopes as well as linear echoendoscopes during PROCESS 2. The studies took place 1 year after another. Local staff sampled each DLE at ≤6 sites according to uniform methods explained by online videos. We used 2 contamination definitions: (1) any microorganism with ≥20 colony-forming units (CFU)/20 mL (AM20) and (2) presence of microorganisms with GI or oral origin, independent of CFU count (MGOs). We assessed the factors of age and usage by performing an analysis of pooled data of both PROCESS studies; additional factors including reprocessing characteristics were only recorded in PROCESS 2. RESULTS: Ninety-seven percent of all Dutch centers (72 of 74; PROCESS 1, 66; PROCESS 2, 61) participated in one of the studies, sampling 309 duodenoscopes and 64 linear echoendoscopes. In total, 54 (17%) duodenoscopes and 8 (13%) linear echoendoscopes were contaminated according to the AM20 definition. MGOs were detected on 47 (15%) duodenoscopes and 9 (14%) linear echoendoscopes. Contamination was not age or usage dependent (all P values ≥.27) and was not shown to differ between the reprocessing characteristics (all P values ≥.01). CONCLUSIONS: In these nationwide studies, we found that DLE contamination was independent of age and usage. These results suggest that old and heavily used DLEs, if maintained correctly, have a similar risk for contamination as new DLEs. The prevalence of MGO contamination of ∼15% was similarly high for duodenoscopes as for linear echoendoscopes, rendering patients undergoing ERCP and EUS at risk for transmission of microorganisms.

Independent root-cause analysis of contributing factors, including dismantling of 2 duodenoscopes, to investigate an outbreak of multidrug-resistant Klebsiella pneumoniae.

BACKGROUND AND AIMS: Worldwide, an increasing number of duodenoscope-associated outbreaks are reported. The high prevalence rate of contaminated duodenoscopes puts patients undergoing ERCP at risk of exogenous transmission of microorganisms. The contributing factors of the duodenoscope design to contamination are not well understood. This article reports on the investigation after the outbreak of a multidrug-resistant Klebsiella pneumoniae (MRKP) related to 2 Olympus TJF-Q180V duodenoscopes. METHODS: We conducted a contact patient screening and microbiologic laboratory database search. Reprocessing procedures were audited, and both duodenoscopes were fully dismantled to evaluate all potential contamination factors. Outcomes were reviewed by an experienced independent expert. RESULTS: In total, 102 patients who had undergone an ERCP procedure from January to August 2015 were invited for screening. Cultures were available of 81 patients, yielding 27 MRKP-infected or -colonized patients. Ten patients developed an MRKP-related active infection. The 2 duodenoscopes had attack rates (the number of infected or colonized cases/number of exposed persons) of 35% (17/49) and 29% (7/24), respectively. Identical MRKP isolates were cultured from channel flushes of both duodenoscopes. The review revealed 4 major abnormalities: miscommunication about reprocessing, undetected damaged parts, inadequate repair of duodenoscope damage, and duodenoscope design abnormalities, including the forceps elevator, elevator lever, and instrumentation port sealing. CONCLUSIONS: Outbreaks are associated with a combination of factors, including duodenoscope design issues, repair issues, improper cleaning, and systemic monitoring of contamination. To eliminate future duodenoscope-associated infections, a multipronged approach is required, including clear communication by all parties involved, a reliable servicing market, stringent surveillance measures, and eventually new duodenoscope designs and reprocessing procedures with a larger margin of safety.

High prevalence rate of digestive tract bacteria in duodenoscopes: a nationwide study.

OBJECTIVE: Increasing numbers of outbreaks caused by contaminated duodenoscopes used for Endoscopic Retrograde Cholangiopancreatography (ERCP) procedures have been reported, some with fatal outcomes. We conducted a nationwide cross-sectional study to determine the prevalence of bacterial contamination of reprocessed duodenoscopes in The Netherlands. DESIGN: All 73 Dutch ERCP centres were invited to sample ≥2 duodenoscopes using centrally distributed kits according to uniform sampling methods, explained by video instructions. Depending on duodenoscope type, four to six sites were sampled and centrally cultured. Contamination was defined as (1) any microorganism with ≥20 colony forming units (CFU)/20 mL (AM20) and (2) presence of microorganisms with gastrointestinal or oral origin, independent of CFU count (MGO). RESULTS: Sixty-seven out of 73 centres (92%) sampled 745 sites of 155 duodenoscopes. Ten different duodenoscope types from three distinct manufacturers were sampled including 69 (46%) Olympus TJF-Q180V, 43 (29%) Olympus TJF-160VR, 11 (7%) Pentax ED34-i10T, 8 (5%) Pentax ED-3490TK and 5 (3%) Fujifilm ED-530XT8. Thirty-three (22%) duodenoscopes from 26 (39%) centres were contaminated (AM20). On 23 (15%) duodenoscopes MGO were detected, including Enterobacter cloacae, Escherichia coli, Klebsiella pneumonia and yeasts. For both definitions, contamination was not duodenoscope type dependent (p values: 0.20 and higher). CONCLUSION: In 39% of all Dutch ERCP centres, at least one AM20-contaminated patient-ready duodenoscope was identified. Fifteen per cent of the duodenoscopes harboured MGO, indicating residual organic material of previous patients, that is, failing of disinfection. These results suggest that the present reprocessing and process control procedures are not adequate and safe.