INFECTION PREVENTION AND CONTROL
different forms of prion diseases… Prions are essentially proteins. Lots of mammal species have encoded PRNP genes, but their role is not fully understood. They exist on the membrane of neural cells, but in the case of disease, the protein misfolds. This misfolded form is known as PrPsc
, and
the reason this is problematic is that it can trigger a chain reaction, leading to an exponential build up, which is associated with irreversible neurodegeneration,” Neil Watson explained. He showed the audience a slide highlighting the spongiform changes in the brain tissue that can be seen under a microscope. Prion disease is transmissible, incurable, and can be rapidly lethal, he pointed out. PrPsc
can also survive outside
Neil Watson, from the National CJD Research & Surveillance Unit, said: “Even today, we are seeing people with different forms of prion diseases.”
a QR code. This means you can monitor where it goes. You put the biodegradable apron into the compostable bin, which is taken away, combined with the food waste (i.e. used as ‘feed stock’), and this is then added to a bio-digestor located on site. Out comes a lovely fertiliser!” Dr. O’Riordan explained. “The end product is pathogen safe; it is nitrogen-rich, dry, odourless, and can be used for horticultural purposes.” This ‘outside of the box’ thinking could
have a significant impact on plastic waste, and help the NHS further its ambitions in achieving greater sustainability, Dr. O’Riordan asserted.
Probiotics Continuing the theme of thinking outside of the box, Elisabetta Caselli, from the University of Ferrara in Italy, gave a presentation titled: ‘Not only the gut: can we really use probiotics to ameliorate the hospital microbiota?’ She explained that hospital environments can be described as ‘super organisms’, as they each have their own microbiome, much like each human being has theirs. It was observed that the more controlled
environment showed a decrease in biodiversity, with the consequence that it increased resistance against antimicrobials and disinfectants. Thus, the hospital environment becomes a reservoir of pathogens, causing 5% to 15% of patients to contract a healthcare-associated infection (HCAI). During the pandemic, hospitals approached cleaning in the conventional way through increased use of chemical disinfectants. They discovered three key limitations: 1. Most chemical disinfectants were inactive within one hour; therefore, their effect was temporary.
2. An increase in the environmental impact to both health and water pollution.
3. An increased selection of antimicrobial resistant strains and cross-resistance occurred.
34 Health Estate Journal May 2024
Elisabetta Caselli’s research group wanted to answer the question, ‘How can the above limitations be overcome while also being microbially effective?’ The researchers considered that rather than eliminating ALL microbes, it may be more effective to replace bad microbes (pathogens) with good ones (probiotics). They developed PCHS (Probiotic Cleaning Hygiene System) – an eco-label detergent containing spores of selected probiotics of the Bacillus genus. A multi-centre study involving six hospitals and five colleges was conducted, which included analysis of surface bioburden and HCAI incidence. The results were as follows: n Pathogens: -80% vs disinfectants. n HCAIs incidence: -52%. n Antibiotic consumption: -60%. n Cost of HCAI therapy: -75%.
Bacconi University concluded that the use of PCHS in the next five years may prevent around 31,000 HCAIs, and save at least ¤14 m – of which ¤11.6 m is for the treatment of HCAIs. Elisabetta Caselli went on to share a
variety of evidence sources to support probiotic cleaning, including findings that it led to an ‘Average reduction up to 99.9% in 24 hours, for Enterococcus faecalis, Candida albicans, Pseudomonas aeruginosa, Acinetobacter baumanni and Klebsiella pneumoniae.’ She concluded that sanitation based on microbiome balance may provide more effective and stable reduction of pathogens, compared with disinfectants, without further worsening AMR and pollution concerns.
Prions Neil Watson, from the National CJD Research & Surveillance Unit, gave an overview of prions disease and the implications for decontamination units. “Even today, we are seeing people with
the host (for years), and retains infectivity. It is resistant to physical/chemical degradation and adheres to surfaces. A range of epidemics and epizootics have been characterised – some continue to expand, while others have curtailed. There are three classes of prion diseases, and all forms are transmissible: n Sporadic (e.g. most CJD in humans) – a sporadic misfolding event.
n Genetic/familial/inherited – mutations in PNRP.
n Acquired – iatrogenic, occupational, dietary/zoonotic.
He pointed out that the vast majority (90- 95%) of cases of prion disease are sporadic without evident transmission, while genetic is the second commonest form (around 5%). Acquired cases (iatrogenic, variant and Kuru) account for <5% of all time, and there are very few cases today. He gave a brief timeline outlining the
emergence of prion disease outbreaks, and some key moments in its history: n In the late 1950s, it was noticed that there were some cases of prion diseases associated with a shared operating list and, over the years, there have been other cluster cases associated with surgery.
n In the 1970s, there was a documented case of a patient who received a corneal transplant who contracted CJD from the deceased donor, and there have also been some cases of CJD linked to intracerebral electrodes implanted in the brain.
n In 1995-96 a ‘new variant’ CJD was identified in the UK and France (vCJD), which exhibited atypical features (clinical, radiological and pathological), which affected the young (i.e. people in their 20s and 30s).
n In 1996, UK beef was banned, and surveillance expanded, following the identification that ‘mad cow disease’ or BSE had entered the human food chain and was linked to the transmission of vCJD in humans.
n Cadaveric hGH and dura mater grafts caused two epidemics. The Dura Mater
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