‘Thinking outside the box’ in reducing HAIs

Held at the iconic Liverpool Medical Institute, the CSC’s Study Day was opened by Jimmy Walker, Chairman of the CSC. The programme provided some thought-provoking presentations on reducing healthcare-associated infections — from the use of probiotics in hospital environments, and balancing infection control with sustainability, to the risks associated with prion diseases and the challenges around difficult-to-clean instruments. Other highlights included the microbiological risks associated with hospital laundry; whether the overestimation of risks around the decontamination of semi-critical devices is ‘less bad’ than underestimation, and the integration of decontamination services in Liverpool.

Thinking outside the box

The first session, ‘Thinking outside the box’ was chaired by Clinical Microbiologist, Mike Simmons, who introduced Dr. Mary O’Riordan, co-founder of HaPPE Earth. A clinical entrepreneur and previously a doctor for over 18 years, Dr. O’Riordan highlighted the issue of plastic PPE pollution in hospitals. It is widely acknowledged that infection prevention has presented some unintended challenges around sustainability — during the pandemic, for example, the use of single-use plastic PPE ‘escalated to enormous quantities’. This is an issue she is keen to address.

Dr. O’Riordan previously worked within the area of public health, specialising in Emergency Response for Highly Emerging, Infectious Threats. She has also been the International Health Regulations (IHR) and ECDC Irish Focal Point representative for emerging infectious threats. She realised there was a risk that her legacy would be ‘to cover the world in plastic’, so she decided to set up a family-owned business called HaPPE Earth (short for Health, Agriculture and PPE). She pointed out that plastic waste is generated at a rate approaching 400 million tonnes per year. Healthcare is a major contributor to the single-use plastics problem. Only 18% of plastic waste is recycled, and 24% is incinerated. The remaining 58% is either sent to landfill or enters the natural environment.

She realised that plastic aprons were an ideal target for improvement. During 2020, Ireland used 70 million plastic aprons and England used around 900 million. The global market is still 98% LDPE usage, with very little in the way of credible alternatives.

However, if the NHS removed single-use plastic aprons, it would mean a reduction in plastic waste by approximately 5,000 tonnes of plastic each year. Furthermore, if UK acute hospitals used on-site bio-digestion, it would mean 1.1 million tonnes of food waste could be eliminated per year and converted to nutrient rich fertiliser.

To address these issues, the company developed a range of compostable, single-use aprons made from a bio-resin — inspired by a material originally used in agriculture to grow crops.

Dr. O’Riordan outlined how the company had approached using different materials that were compostable as an alternative product to make Class 1 medical device PPE. The concept was to locate a bin in the ward, or by the bedside, which is taken to a central bio-digestion system, where it is treated to neutralise any pathogens and made into nutrient-rich fertiliser or biofuel. By locating the manufacture of the aprons in Ireland, the carbon footprint is also significantly reduced compared with importing aprons from overseas.

An initial trial was carried out at a local hospital in Ireland. “The staff loved it. It looked the same, it was breathable and met all the standards, so everyone was happy,” she commented.

She added that the concept has helped to move away from the traditional incineration cycle, by setting up a complete solution that includes food waste into the bio-digestion cycle.

“We created a compostable bin that has 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.

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:

Pathogens: -80% vs disinfectants.
HCAIs incidence: -52%.
Antibiotic consumption: -60%.
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 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 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:

Sporadic (e.g. most CJD in humans) — 
a sporadic misfolding event.
Genetic/familial/inherited — 
mutations in PNRP.
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:

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.
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.
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).
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.
Cadaveric hGH and dura mater grafts caused two epidemics. The Dura Mater cases were mainly in Japan — other nations ceased using such grafts in 1987, but Japan continued until 1997. The hGH cases were mainly in the UK and France, although cases continue to be identified, and the longest incubation is 44 years.
vCJD deaths peaked globally in the early 2000s. However, in 2004 and 2006, there were three cases of vCJD linked to transfusion, and one case with preclinical disease.
In 2010, splenic PrP was identified in haemophiliacs who had received plasma.
Studies in 2015 indicated the possibility of amyloid transmission.
In 2016, a chronic wasting disease was discovered in deer herds.
In 2019, two lab workers died of vCJD.

“We see the emergence of evidence of iatrogenic transmission arising from medical procedures, along with the realisation that there is resistance to degradation through decontamination measures,” he commented. This helped to solidify the theory that transmission was due to a protein rather than a virus.

He pointed out that there is no ability to test donors for pre-clinical status for vCJD. No other forms of CJD have been transmitted via blood or organs, and screening questionnaires explore the risk status (family, Hx, exposures). Global restrictions around UK donors are now relaxing, and the UK plasma ban has been lifted.

However, in recent years, studies have tested appendix samples to establish if there is sub-clinical carriage of vCJD prion material, in people who are not symptomatic.

“Alarmingly, these tests have suggested that there may be individuals who are carrying this material in their appendix tissue — the estimates are around 1 in 2000-4200 people. We don’t know what that means yet — is this just trace detection and they are not infective, or are these people incubating it? If so, do these people pose a risk via blood, surgery, or organ transplantation?

“Nobody really knows what to make of this, except that exposure was perhaps widespread in our diet — especially in the UK. However, whether these people will go on to manifest this disease remains to be seen,” commented Neil Watson.

In the last few years, there has been a case of vCJD where the individual was found to be ‘a longer incubator’ and atypical in terms of genotype. This also raises the question of whether there may be individuals with a longer incubation than the ‘first wave’. If so, could a ‘second wave’ be yet to come?

He added that there are implications to consider around surgical and medical procedures (before and after exposures); blood; laboratories, and waste; but CJD is not spread through skin, urine and saliva, and CJD patients do not need to be isolated. Some studies do implicate increased risk in healthcare workers, although the epidemiology is complicated (e.g. reporting biases). In non-variant forms, PrPsc is not peripherally distributed. Tissues are categorised by high risk level (brain, spinal cord, and posterior eye = high risk; olfactory epithelium = medium risk; all others = low risk.)

vCJD differs, and is found in lymphoreticular tissues (tonsils, appendix, spleen and nodes), so there is separate guidance relating to this. Guidance may refer to patients who have symptomatic disease or have been ‘exposed’ (and are ‘at risk’), via donated blood from a person known to have had the disease, for example. Patients identified as being ‘at risk’ may be treated at the end of a surgical list, and they may require single-use, disposable instruments, although this is not always possible. He highlighted the importance of track and trace to ensure patient safety.

If the tissues are low risk, there are no special measures. For medium/high risk, single use/destroy/quarantine for reuse on the same patient are options. NICE suggests this is not cost-effective, however, and recommends decontamination — the options include NaOH + autoclave.

In summary, prion diseases are transmissible but not contagious, so a rational stratification of tissue/procedure risk should be used. There are cost-effectiveness and sustainability issues to be considered around single-use instruments. However, there are emerging questions around amyloid (and others) which require caution. There is uncertainty around whether these are truly transmissible, and what the implications would be.

Prions and the cleaning 
of instruments

Given the potential risks around prions, removal of proteins on medical devices is an important area of focus — particularly in relation to difficult-to-clean instruments. The next presentation sought to promote discussion and review of current practices within decontamination departments. Jim Tinsdeall, AE(D), reviewed the difference between guidance, law, and standards — highlighting the challenges around varying interpretations.

1. ‘The Law’ includes: the Health Act 2008, MDD, MDR, consumer protection act, HSWA 1974, COSHH etc.

2. ‘Guidance’ includes:

ACDP TSE guidance 2015: Minimise transmission risk of CJD and vCJD in healthcare settings.
Health & Social Care Act 2008: code of practice on the prevention and control of infections (13 December 2022).
NICE IPG666 (2020): Reducing risk of transmission of CJD from surgical instruments used for interventional procedures on high-risk tissues.
HTM 01-01 — decontamination of surgical instruments.

3. ‘Standards’ include: BS EN ISO 13484.

Jim Tinsdeall highlighted that these documents sometimes contain information that is conflicting or lacks clarity — for example, there is no agreement over the level of residual protein. He highlighted guidance within HTM 01-01 on residual protein numbers, which states that the upper limit of 5 µg per side of instrument should be achieved, with a need for continuous improvement.

He pointed out that the reason for the need for ‘continued improvement’ is the fact that ‘there is actually no safe level’ of protein. The guidance within NICE IPG666 states that intracranial transfer of 0.01 µg of brain tissue could result in the recipient having a 50% chance of becoming infected with CJD.

“This is a miniscule amount required for transmission, but the 5 µg [in the aforementioned HTM 01-01] gives us many hundreds of doses,” he commented. Standard BS EN 15883 states it should be less than 6.4 µg per cm2.

Jim Tinsdeall pointed out that, given the incubation period of 1-42 years, it is difficult to learn from incidents which might otherwise prompt efforts to change practices. Departments often say they are ‘following manufacturers’ instructions’, but it is the processor that is accountable and responsible for ensuring the desired result. Therefore, they must carry out tests to prove the required levels of decontamination have been achieved. There are conflicting messages around testing methods, however. HTM 01-01 refers to measuring ‘directly on the surface, rather than by swabbing or elution’, while the standard BS EN ISO 15883-1 2009 refers to the ‘Biuret method (swabbing), or ortho-phthalic-acid-dialdehyde OPD (elution) or Ninhydrin’.

The speaker stated that testing is a case of ‘horses for courses’, depending on the design challenges of the instrument, and he went on to show some slides of some difficult-to-clean instruments. In some cases, neither ‘measuring directly on the surface’ or ‘swabbing’ would give an accurate indication of protein located in the hard to access areas; elution in a lab might be the best option in such cases, and the lab may need to disassemble the instrument.

He highlighted some test results on ‘remote working surgical instruments’, which led to some improvements. By keeping the instruments moist and speeding up the process (by removing transport delays), the protein residues were reduced to a quarter of the levels detected prior to the changes.

“If we don’t test and we don’t know, we are just blindly carrying on,” he asserted.

While keeping instruments moist will improve protein removal, who is responsible for monitoring this? Sterile services departments often see variations in practices — some instruments will arrive at the SSD properly bagged and sprayed, to keep them kept moist, while others arrive simply wrapped in paper, and are allowed to dry out.

Automation is also important — ideally, we should aim to move away from manual processes, such as brushing, to the flushing of lumens.

“The problem with manual processes, is that we all have off days,” he commented.

Jim Tinsdeall also suggested that Sterile services departments should double process devices where inspection is not possible — this may include manual, ultrasonic, or connection to lumens in the washer-disinfector. It is important to quantify the residual protein, using the best methods available, and departments should ‘review, revise, and improve’. If resolution is not possible, this should be included on the Risk Register.

Infection risks and laundry

The afternoon session looked at the risks associated with laundry decontamination. Karren Staniforth, from the UK Health Security Agency, shared her findings and observations from investigations into outbreaks across the UK. She highlighted the risk of contamination to people handling the laundry, and the risks of patients acquiring infection from re-contaminated laundry, citing a range of literature as evidence that these acquisitions occur.

Among the literature was an investigation into an outbreak of mucormycosis in a paediatric oncology unit — linked to water damage arising in a linen store, located adjacent to the parent’s shower room (Garnet et al, 2008). This demonstrates how poorly maintained laundry storage rooms can pose a potential risk. However, recontamination of laundry can also occur due to contact with laundry staff with skin or enteric infections and poor practice. Other routes for contamination include laundry floors, roll cages, and vans, when there is a failure to follow cleaning and handling procedures, which prevent recontamination.

There is also a risk arising from decontamination failures. Linen may appear clean, but the microbial load may remain high if thermal disinfection has not been reached. Temperature and contact times need to be achieved consistently, and laundry decontamination should be a quality assured process. Changing the load (without re-validation), or pausing and restarting the continuous batch washer (CBW) after it has cooled, can cause failure, but these may go undetected and unreported.

Karren Staniforth pointed out that spore forming bacteria such as Bacillus cereus and Clostridioides difficile will survive disinfection (e.g. 71 °C for three minutes). Spores are removed by mechanical action and dilution, but if contamination is high, a significant number of potentially infectious spores can remain attached to linen. This is particularly a problem when bacterial contaminates replicate during transportation of used linen, during the warmer summer months.

She concluded that:

Bacillus cereus is implicated in 57% of all laundry-related outbreaks of infection.

Cases and outbreaks may be undetected and unreported.

It is easier to maintain control than to reduce counts once control has been lost.

Active laundry testing is recommended during summer months.

Total blood culture isolates can easily be monitored throughout the year.

Simply increasing the rinse-water volume may not be sufficient to regain control, and excess water may have a negative impact on mechanical action.

More research, guidance, support, and training, would be useful in preventing and managing these outbreaks and incidents.

It was evident, from Karren Staniforth’s presentation, that laundry validation is not as robust as reusable medical devices, and this is an area of decontamination that requires improvement for the future.

A detailed insight into the standards and HTM guidance for laundry decontamination followed, by Wayne Spencer, a Consultant from Spencer Nickson. He pointed out that one of the reasons for the introduction of HTM 01-04 was the fact that the segregation of foul and infected linen was not working. In reality, large amounts of water-soluble bags are opened by staff and then discarded as waste; staff are having to open the water-soluble bags manually, as the continuous tunnel washer (CTW) struggles to process them in large volumes; and most laundries are pre-sorting linen — including infectious linen. Wayne Spencer discussed the way forward to achieving ‘a safer future’, which included the following:

1. Linen processors who process infectious laundry should adopt bag handling and opening procedures that:

n Do not use liquid permeable bags.

n Minimise manual handling/opening of infectious linen and any other exposure to staff to the linen prior to decontamination.

n Are fully automated for washer loading (once the technology has been developed to allow this).

n Are capable of being adequately disinfected.

2. It is envisaged that easy-emptying impermeable bags combined with step conveyor type systems could be implemented which may, if installed and operated correctly, provide an alternative to using water-soluble bags in CTWs.

3. Any systems adopted should not expose the laundry staff to any greater risk than that posed by the use of water-soluble bags.

He pointed out that the HTM guidance was a ‘starting point to raise awareness’, but further work is required. He suggested that it may be time to include a test method and conduct research into threshold limits. This will help with effectively identifying and managing infectious laundry risks.

Semi-critical reusable devices

John Prendergast, NHS Wales Shared Services Partnership/Specialist Estates, challenged whether over estimation of risk was better than under estimation for semi-critical reusable devices. He revisited Spaulding’s criteria, and highlighted that investigations have shown there is a risk of infection transmission from equipment to patients. He cited a number of high-profile reports where patients have contracted infections (in some cases leading to fatalities), which involved reusable equipment such as transoesophageal echocardiography probes and laryngoscope handles. He also highlighted the findings of a key study concerning ultrasound probes.

Patient records from the Electronic Communication of Surveillance in Scotland and the Prescribing Information System were linked with the Scottish Morbidity Records for cases in Scotland, between 2010 and 2016. The analysis sought to quantify the association between semi-invasive ultrasound probe procedures and the risk of positive microbiological reports and community antibiotic prescribing in the 30-day period following this procedure. The study demonstrated a greater risk of infection within 30 days of undergoing semi-invasive ultrasound procedures, and estimated that up to 7% of ultrasound probes were contaminated with HPV.

In order to reduce infection risks, he suggested we consider the following:

Transmission of infection as a result of inadequate decontamination — can we improve systems?
Can the service be transferred to a more appropriate setting?
Can we use automated high-level disinfection (HLD) systems? Are we using the most effective wipes (compatible)? Is the environment safe for staff (exposure to chemicals/ventilation etc)?
IPC team to audit routinely (i.e. IPC staff with knowledge).
Routine training of staff, annual refreshers/induction training (decontamination principles).
Correct use of sheaths/ultrasound gel.
Utilise/develop guidance.
Utilise expert help available (Decontamination Lead, IPC, AE(D) etc) to advise on and support improvement.

Integration of services

Finally, the study day concluded with a presentation by Robbie Cormie, Trust Decontamination Lead, Liverpool University Hospitals NHS Foundation Trust, who provided an overview of his journey in the integration of decontamination services across Liverpool, Cheshire, and Merseyside.

Integration proved to be a challenging and complex process, involving the standardisation of equipment and systems, but it also provided opportunities for cost savings, joint venture working, sharing of best practice, and the repatriation of outsourced sterile services. He reported that there was a £100k underspend, by taking instrument decontamination back in house, and instrument repairs and replacements are now completed usually within seven days.

He concluded his talk with a quote from Charles Darwin: “It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change.”

Ultimately, the study day highlighted some excellent examples of ‘thinking outside of the box’, while encouraging discussion of some key challenges in decontamination. The thought-provoking content invited delegates to consider ‘what can we do differently?”, to defy the dogma, and to implement positive change back at their respective organisations.

Acknowledgement

This article, titled ‘Dare to defy the dogma in decontamination’, first appeared in a ‘Decontamination & Sterilisation’ supplement as part of the April 2024 issue of The Clinical Services Journal (‘CSJ’). HEJ thanks the magazine’s editor for allowing its reproduction here.