A narrative review on current duodenoscope reprocessing techniques and novel developments

Duodenoscopy-associated infections occur worldwide despite strict adherence to reprocessing standards. The exact scope of the problem remains unknown because a standardized sampling protocol and uniform sampling techniques are lacking. The currently available multi-society protocol for microbial culturing by the Centers for Disease Control and Prevention, the United States Food and Drug Administration (FDA) and the American Society for Microbiology, published in 2018 is too laborious for broad clinical implementation. A more practical sampling protocol would result in increased accessibility and widespread implementation. This will aid to reduce the prevalence of duodenoscope contamination. To reduce the risk of duodenoscopy-associated pathogen transmission the FDA advised four supplemental reprocessing measures. These measures include double high-level disinfection, microbiological culturing and quarantine, ethylene oxide gas sterilization and liquid chemical sterilization. When the supplemental measures were advised in 2015 data evaluating their efficacy were sparse. Over the past five years data regarding the supplemental measures have become available that place the efficacy of the supplemental measures into context. As expected the advised supplemental measures have resulted in increased costs and reprocessing time. Unfortunately, it has also become clear that the efficacy of the supplemental measures falls short and that duodenoscope contamination remains a problem. There is a lot of research into new reprocessing methods and technical applications trying to solve the problem of duodenoscope contamination. Several promising developments such as single-use duodenoscopes, electrolyzed acidic water, and vaporized hydrogen peroxide plasma are already applied in a clinical setting

A dynamic flow model mimicking duodenoscope reprocessing after bacterial contamination for translational research

OBJECTIVE: Duodenoscopy-associated infections and outbreaks are reported globally despite strict adherence to duodenoscope reprocessing protocols. Therefore, new developments in the reprocessing procedure are needed. DESIGN: We evaluated a novel dynamic flow model for an additional cleaning step between precleaning and manual cleaning in the reprocessing procedure. METHODS: A parallel plate flow chamber with a fluorinated ethylene propylene bottom plate was used to mimic the duodenoscope channels. The flow chamber was inoculated with a suspension containing Klebsiella pneumoniae to simulate bacterial contamination during a duodenoscopic procedure. After inoculation the flow chamber was flushed with a detergent mimicking precleaning. Subsequently the flow chamber was subjected to different interventions: flow with phosphate-buffered saline (PBS), flow with 2 commercial detergents, flow with sodium dodecyl sulfate with 3 different concentrations, and flow with microbubbles. Adhering bacteria were counted using phase-contrast microscopy throughout the experiment, and finally, bacterial viability was assessed. RESULTS: During precleaning both PBS and 1% (v/v) Neodisher Mediclean Forte were able to desorb bacteria, but neither proved superior. After precleaning only sodium dodecyl sulfate could desorb bacteria. CONCLUSIONS: Flushing during precleaning is an essential step for reducing adhering luminal bacteria, and sodium dodecyl sulfate is a promising detergent for bacterial desorption from duodenoscope channels after precleaning

Clinical consequences of PCR based diagnosis of intestinal parasitic infections

The implementation of Polymerase Chain Reaction (PCR) based diagnostics of intestinal protozoa have led to higher sensitivity and (subtype) specificity, more convenient sampling and the possibility for high-throughput screening. An increasing number of clinical laboratories use PCR for routine detection of human intestinal protozoa in fecal samples. This paper discusses the recent developments in the diagnosis of intestinal protozoa, with an emphasis on PCR based diagnostics. Though many reviews have described the technical aspects of PCR based diagnostics, this review focuses on the clinical consequences that result from the shift from microscopic toward PCR based diagnostics. Despite its undisputed superiority, the use of PCR has challenges that clinicians should be aware of. This article is protected by copyright. All rights reserved

A clinical guideline on Dientamoeba fragilis infections

Dientamoeba fragilis (D. fragilis) is an intestinal parasite frequently detected in humans with abdominal pain and diarrhoea, but it is also commonly found in asymptomatic subjects. Hence its clinical relevance is often disputed. The introduction of polymerase chain reaction (PCR) is a versatile and sensitive diagnostic technique for the detection of intestinal parasites, and in some Western world countries PCR has almost completely replaced microscopic diagnostics. PCR has however resulted in an increase in the number of D. fragilis-positive patients. The disputed pathogenic nature of this intestinal parasite and an apparent increase in the incidence of patients with positive PCR results have renewed the discussions between clinicians and microbiologists on how to deal with an infected patient. Moreover, treatment guidelines differ throughout the world which makes it difficult for clinicians to choose an optimal therapeutic regimen.AimTo summarize and discuss the current knowledge on the pathogenicity, best diagnostic approach, treatment and follow-up of children and adults infected with D. fragilis

Clinical consequences of PCR based diagnosis of intestinal parasitic infections

The implementation of Polymerase Chain Reaction (PCR) based diagnostics of intestinal protozoa have led to higher sensitivity and (subtype) specificity, more convenient sampling and the possibility for high-throughput screening. An increasing number of clinical laboratories use PCR for routine detection of human intestinal protozoa in fecal samples. This paper discusses the recent developments in the diagnosis of intestinal protozoa, with an emphasis on PCR based diagnostics. Though many reviews have described the technical aspects of PCR based diagnostics, this review focuses on the clinical consequences that result from the shift from microscopic toward PCR based diagnostics. Despite its undisputed superiority, the use of PCR has challenges that clinicians should be aware of. This article is protected by copyright. All rights reserved

A clinical guideline on Dientamoeba fragilis infections

Dientamoeba fragilis (D. fragilis) is an intestinal parasite frequently detected in humans with abdominal pain and diarrhoea, but it is also commonly found in asymptomatic subjects. Hence its clinical relevance is often disputed. The introduction of polymerase chain reaction (PCR) is a versatile and sensitive diagnostic technique for the detection of intestinal parasites, and in some Western world countries PCR has almost completely replaced microscopic diagnostics. PCR has however resulted in an increase in the number of D. fragilis-positive patients. The disputed pathogenic nature of this intestinal parasite and an apparent increase in the incidence of patients with positive PCR results have renewed the discussions between clinicians and microbiologists on how to deal with an infected patient. Moreover, treatment guidelines differ throughout the world which makes it difficult for clinicians to choose an optimal therapeutic regimen.AimTo summarize and discuss the current knowledge on the pathogenicity, best diagnostic approach, treatment and follow-up of children and adults infected with D. fragilis

Growth hormone-, alpha-subunit and thyrotrophin-cosecreting pituitary adenoma in familial setting of pituitary tumour

A patient with acromegaly and hyperthyroidism due to a growth hormone-, thyrotrophin- and alpha-subunit-secreting pituitary adenoma is described. His deceased father had suffered from a pituitary tumour, and was likely to have had acromegaly as well. Plasma growth hormone and insulin-like growth factor I concentrations were elevated, with levels between 10 and 20 mu g/l and 4.4 and 7.3 kU/l, respectively. In spite of hyperthyroidism (free thyroxine, 45 pmol/l; free triiodothyronine, 24 pmol/l), plasma thyrotrophin remained at 2.8 mU/l without any response to thyrotrophin-releasing hormone and could not be suppressed with exogenous administration of triiodothyronine. Plasma alpha-subunits were raised to 3.3-3.7 U/l (normal 0.4-1.1 U/l). Pathological examination of the surgically removed tumour showed a pituitary adenoma with the immunohistochemical presence of growth hormone, thyrotrophin, prolactin and alpha-subunit. This is the first report of a growth hormone-, thyrotrophin- and alpha-subunit-producing pituitary adenoma, which occurred in a familial setting

Esophageal pH-Impedance Monitoring in Patients With Therapy-Resistant Reflux Symptoms:'On' or 'Off' Proton Pump Inhibitor?

BACKGROUND: In patients with proton pump inhibitor (PPI)-resistant symptoms, ambulatory 24-h pH-impedance monitoring can be used to assess whether a relationship exists between symptoms and reflux episodes. Until now, it is unclear whether combined pH-impedance monitoring in these patients should be performed on or off PPI. METHODS: Thirty patients with symptoms of heartburn, chest pain, and/or regurgitation despite PPI twice daily underwent ambulatory 24-h pH-impedance monitoring twice, once on PPI and once after cessation of the PPI for 7 days. The order of the measurements was randomized. Reflux episodes were identified and classified as acid, weakly acidic, or weakly alkaline reflux. In addition, the symptom association probability (SAP) was calculated for each measurement. RESULTS: The total number of reflux episodes and proximal extent were not affected by PPI therapy. On PPI, there were fewer acid reflux episodes (49 +/- 34 off PPI vs 20 +/- 25 on PPI) while more weakly acidic reflux episodes were identified (24 +/- 17 off PPI vs 48 +/- 31 on PPI). Symptom association analysis identified 15 and 11 patients with a positive SAP in the measurement off and on PPI, respectively, the difference in yield of the SAP not being statistically significant. Eight of the 19 patients who had no symptoms or a negative SAP during measurement on PPI had a positive SAP off PPI therapy. In contrast, only 4 patients with a positive SAP on PPI were missed in the measurement off PPI therapy. CONCLUSIONS: In order to demonstrate or exclude GERD in patients with PPI-resistant symptoms, ambulatory 24-h pH-impedance monitoring should preferably be performed after cessation of PPI therapy because this approach seems to offer the best chance to assess a relationship between symptoms and reflux episode

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