Effect of novel endoscope cleaning brush on duodenoscope contamination

Background and aims:Current duodenoscope reprocessing protocols are insufficient to prevent contamination and require adaptations to prevent endoscopy-associated infections (EAI). This study aimed to investigate the effect of a new endoscope cleaning brush on the contamination rate of ready-to-use duodenoscopes. Methods:This retrospective before-and-after intervention study collected duodenoscope surveillance culture results from March 2018 to June 2022. Contamination was defined as ≥1 colony-forming units of gastrointestinal or oral microorganisms (MGO). In December 2020, an endoscope cleaning brush with a sweeper design was introduced as the intervention in the manual cleaning of duodenoscopes. A logistic mixed effects model was used to study the effects of the intervention. Results:Data were collected from 176 culture sets before the new brush's introduction and 81 culture sets after. Pre-introduction, culture sets positive with MGO comprised 45.5% (95% CI: 38.3%-52.8%, 80/176), decreasing to 17.3% (95% CI: 10.6%-26.9%, 14/81) after implementing the new brush. Compared to the former brush, duodenoscopes cleaned with the new brush had lower odds of contamination with MGO (aOR=0.25, 95% CI: 0.11-0.58, p=0.001).Conclusions:Use of the new brush in manual cleaning reduced contamination with MGO and is expected to prevent EAIs. These findings should be confirmed in future prospective randomized studies.</p

Practical principled FRP: Forget the past, change the future, FRPNow!

We present a new interface for practical Functional Reactive Programming (FRP) that (1) is close in spirit to the original FRP ideas, (2) does not have the original space-leak problems, without using arrows or advanced types, and (3) provides a simple and expressive way for performing IO actions from FRP code. We also provide a denotational semantics for this new interface, and a technique (using Kripke logical relations) for reasoning about which FRP functions may "forget their past", i.e. which functions do not have an inherent space-leak. Finally, we show how we have implemented this interface as a Haskell library called FRPNow

The Key monad: Type-safe unconstrained dynamic typing

We present a small extension to Haskell called the Key monad. With the Key monad, unique keys of different types can be created and can be tested for equality. When two keys are equal, we also obtain a concrete proof that their types are equal. This gives us a form of dynamic typing, without the need for Typeable constraints. We show that our extension allows us to safely do things we could not otherwise do: it allows us to implement the ST monad (inefficiently), to implement an embedded form of arrow notation, and to translate parametric HOAS to typed de Bruijn indices, among others. Although strongly related to the ST monad, the Key monad is simpler and might be easier to prove safe. We do not provide such a proof of the safety of the Key monad, but we note that, surprisingly, a full proof of the safety of the ST monad also remains elusive to this day. Hence, another reason for studying the Key monad is that a safety proof for it might be a stepping stone towards a safety proof of the ST monad

A Search Strategy for Detecting Duodenoscope-Associated Infections:A Retrospective Observational Study

Background: Duodenoscope-associated infections (DAIs) are exogenous infections resulting from the use of contaminated duodenoscopes. Though numerous outbreaks of DAI have involved multidrug-resistant micro-organisms (MDROs), outbreaks involving non-MDROs are also likely to occur. Detection challenges arise as these infections often resolve before culture or because causative strains are not retained for comparison with duodenoscope strains. Aim: To identify and analyse DAIs spanning a seven-year period in a tertiary care medical centre. Methods: This was a retrospective observational study. Duodenoscope cultures positive for gastrointestinal flora between March 2015 and September 2022 were paired with duodenoscope usage data to identify patients exposed to contaminated duodenoscopes. Analysis encompassed patients treated after a positive duodenoscope culture and those treated within the interval from a negative to a positive culture. Patient identification numbers were cross-referenced with a clinical culture database to identify patients developing infections with matching micro-organisms within one year of their procedure. A ‘pair’ was established upon a species-level match between duodenoscope and patient cultures. Pairs were further analysed via antibiogram comparison, and by whole-genome sequencing (WGS) to determine genetic relatedness. Findings: Sixty-eight pairs were identified; of these, 21 exhibited matching antibiograms which underwent WGS, uncovering two genetically closely related pairs categorized as DAIs. Infection onset occurred up to two months post procedure. Both causative agents were non-MDROs. Conclusion: This study provides crucial insights into DAIs caused by non-MDROs and it highlights the challenge of DAI recognition in daily practice. Importantly, the delayed manifestation of the described DAIs suggests a current underestimation of DAI risk.</p