DH publishes fresh guidance on Pseudomonas in hospital water systems

Trusts ordered to set up water safety groups to monitor and investigate outbreaks after deaths of babies in Northern Ireland

Hospital trusts will have to set up water safety groups in a bid to deal with the potential for Pseudomonas in water systems

NHS trusts across England are being ordered to form water safety groups as the Department of Health (DH) steps up measures to prevent outbreaks of Pseudomonas infection following the deaths of four babies at neonatal units in Northern Ireland last year.

Pseudomonas is an opportunistic pathogen that can colonise and cause infection in patients who have compromised immunity or whose defences have been breached, for example via a surgical site, tracheostomy or indwelling medical device such as a vascular catheter.

An investigation into the deaths in Northern Ireland revealed the outbreaks were linked to contaminated tap water in the intensive care rooms of the neonatal units. Researchers concluded the most likely method of spread to the babies was the use of tap water for washing during nappy changes.

Pseudomonas bacteria thrives in water systems, particularly large-scale ones such as those found in big industrial buildings, leisure centres and hospitals. Older hospital buildings are particularly at risk as, when the water system is adapted for a change of use or to feed new buildings, deadlegs are created. These are pipes that are effectively cut off, leaving a small dead end where water can become trapped. This stagnant water is a known breeding ground for Pseudomonas bacteria.

To promote good hand hygiene, handwash basin provision has increased significantly in all clinical areas. However, in many situations this has led to underused water outlets and low water throughput. Such outlets form a greater risk of contamination by Pseudomonas than those that are used more frequently

Once in a water system, the bugs grow rapidly, creating a sticky biofilm on pipework. This protects and harbours them and allows them to quickly multiply and take hold.

Pseudomonas is known to flourish particularly well where it has access to a higher level of oxygen and the temperature is between 11˚C-44˚C, although some are able to multiply at just 4˚C.

In an effort to provide guidance for NHS trusts on how to minimise the threat of Pseudomonas in the water supply, the DH published technical guidance in 2012. And this week it has unveiled an addendum to that guidance that builds on and supersedes the original document, dealing with ‘augmented care settings’. This refers to areas where patients are severely immunosuppressed because of disease or treatment; units where organ support is necessary such as respiratory, renal and critical care wards; and places where patients have extensive breaches in dermal integrity and require contact with water as part of their continuing care, such as in burns units.

The publication is concerned with controlling and minimising the risk of morbidity and mortality due to Pseudomonas associated with water outlets, giving guidance on forming a water safety group (WSG), assessing the risk to patients when water systems become contaminated, what remedial actions to take when water systems are affected, and protocols for sampling, testing and monitoring water supplies.

The document outlines the need for trusts to appoint a multi-disciplinary WSG that will be responsible for commissioning and developing a Water Safety Plan and advising on the remedial action required when water systems or outlets are found to be contaminated and the risk to susceptible patients is increased.

In new premises, the provision, correct siting and installation of showers and handwash basins, particularly in accommodation where patients are unlikely to make use of them, requires assessment

The panel, which may be a sub group of the trust’s infection control committee, will typically comprise the director of infection prevention and control, a consultant medical microbiologist, estates and facilities representatives, and senior nurses from the relevant augmented care settings. All episodes of contamination or suspected infection would be reported by the infection prevention team to the chairman of the WSG, who will then initiate an investigation.

The WSG will also be responsible for overseeing any changes to water systems through building works or upgrades and will approve all items of equipment that need to be attached to water distribution systems that are used in direct patient care.

The Water Safety Plan the WSG writes will provide a risk management approach to the microbiological safety of water and establish good practices in local water usage, distribution and supply. To do this, the WSG will need to gain a comprehensive understanding of the water system, including the potential hazards.

The document should identify areas within hospitals with at-risk patients and incorporate a clinical risk assessment to identify those settings where patients are at significant risk from Pseudomonas contamination associated with water use and its distribution system. It should also include details of:

  • An engineering risk assessment of the water system
  • Operational monitoring of control measures
  • Links to clinical surveillance which can offer an early warning of poor water quality
  • Plans for the sampling and microbiological testing of water in identified at-risk units
  • Changes to the water system to remedy high counts for Pseudomonas and other opportunistic pathogens where appropriate
  • Adjustments to clinical practice until remedial actions have been demonstrated to be effective
  • Regular removal/cleaning/descaling or replacement of the water outlets, hoses and thermal mixing valves (TMVs) where there may be direct or indirect water contact with patients
  • Amendments when changes are carried out and at annual review, including new builds, refurbishments and recently decommissioned clinical departments or units
  • Documentation and record-keeping
  • A review of the results of any water testing regimen undertaken

The guidance states that the increase in outbreaks is possibly connected with changes to the way modern health services operate, in particular the introduction on single en-suite inpatient facilities. It adds: “With the change in focus towards improving the patient environment and minimising the risk of healthcare-associated infections, there has been an increase in the provision of single-bed rooms with en-suite facilities. Additionally, to promote good hand hygiene, handwash basin provision has increased significantly in all clinical areas. However, in many situations this has led to underused water outlets and low water throughput. Such outlets form a greater risk of contamination by Pseudomonas than those that are used more frequently.”

Water systems and taps have also become more complex, in some cases increasing the potential for bacteria to multiply.

Every effort should be made when planning, designing and installing new or modified systems to minimise and remove potential hazards, for example oversized water storage tanks, flexible hoses, stagnant water, poor temperature control, long branch pipes and dead-legs, as well as enabling access for monitoring and maintenance

The guidance states: “Every effort should be made when planning, designing and installing new or modified systems to minimise and remove potential hazards, for example oversized water storage tanks, flexible hoses, stagnant water, poor temperature control, long branch pipes and dead-legs, as well as enabling access for monitoring and maintenance.

“In new and existing premises, therefore, it is essential that the needs of individual patient washing and bathing requirements are carefully considered. In new premises, the provision, correct siting and installation of showers and handwash basins, particularly in accommodation where patients are unlikely to make use of them, requires assessment. For existing premises, and subject to a risk assessment, permanent removal of existing outlets and their associated pipework should be considered.”

On the issue of tap selection, the document states: “Tap design has evolved. In older installations, thermostatic control of water temperature was achieved by a separate thermostatic mixing valve (TMV) typically located behind the sanitary assembly panel to which a handwash basin or other assembly was fitted, which then supplied water to the hot connection of a manual mixing tap or separate tap.

“Many new installations now include taps of a modern design with integral TMVs. They are usually manually controlled and can be adjusted to further reduce outlet temperature to fully cold. For some applications, remote sensor-operated taps are available. In some instances these developments have led to a more complicated internal tap design which may increase the need for additional routine maintenance, including decontamination, to mitigate the risk of contamination by Pseudomonas .

“The choice and type of water outlets for the augmented care setting is, therefore, important. This choice should be based on a risk assessment of infection control and scalding issues.

There is some evidence that the more complex the design of the outlet assembly, for example some sensor-operated taps, the more prone to Pseudomonas colonisation the outlet may be

“There is some evidence that the more complex the design of the outlet assembly, for example some sensor-operated taps, the more prone to Pseudomonas colonisation the outlet may be. In intensive care and other critical care areas, where patients are unlikely to be able to use the handwash basins, the installation of non-TMV mixing taps may be the preferred control option following a risk assessment.”

To read the full guidance, click here.

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