Non-touch taps could be fuelling Pseudomonas outbreak, report claims

31-Aug-2012

Manufacturers urged to redesign healthcare plumbing systems as report suggests link between taps and Pseudomonas

Manfacturers of healthcare taps and plumbing systems are being urged to reconsider equipment design after a Department of Health report suggested measures taken to prevent MRSA could be creating the ideal environment for deadly Pseudomonas bacteria to thrive.

The concerns are outlined in the recently-published Report On the Review of Evidence Regarding the Contamination of Wash Hand Basin Water Taps Within Augmented Care Units with Pseudomonas.

The document is based on investigations carried out by the Pseudomonas Working Group following several outbreaks of the deadly bug in adult intensive care units in England and Wales over recent years. However, the probe was completed before the deaths of four infants last December at the Royal Jubilee Maternity Hospital and Altnagelvin Hospital in Northern Ireland.

The working group included representatives from the NHS, royal colleges, the Health Protection Agency, the Health and Safety Executive, the Water Research Centre, the Drinking Water Inspectorate, the Water Regulations Advisory Scheme, BuildCert, and manufacturing trade associations and looked at possible causes of Pseudomonas outbreaks and the evidence for the various control measures.

In its desire to reduce hand contact points to control MRSA, many augmented care units have moved to infrared-operated taps. These devices usually require the use of an artificial rubber diaphragm which, because of a greater surface area, will further increase the amounts of utilisable carbon sources available and the area on which biofilm can locate.”

And it has hinted at a link between the introduction of automatic sensor taps to improve hand hygiene and prevent MRSA and a possible increase in Pseudomonas contamination.

“In its desire to reduce hand contact points to control MRSA, many augmented care units have moved to infrared-operated taps, which are switched on by the use of a solenoid,” the report states. “These devices usually require the use of an artificial rubber diaphragm which, because of a greater surface area, will further increase the amounts of utilisable carbon sources available and the area on which biofilm can locate.”

Work carried out to date has suggested the build-up of biofilm in water systems provides protection for Pseudomonas bacteria, enabling it to multiply. The slime also makes it more difficult to remove it once it has taken hold.

The report reveals that, while the long-term impact is unknown, trusts that have replaced infrared non-touch taps with traditional elbow or knee-activated devices have seen an end to Pseudomonas contamination for at least the reported period. The typical bill for replacing all non-touch taps in a standard large NHS intensive care unit is estimated at around £2,500 per unit, with a £50,000-a-year running cost.

This finding has led to calls for suppliers to consider a redesign of healthcare tap and water systems, including the possible use of new materials.

The report states: “Manufacturers should be encouraged to seek alternative designs that reduce the risk by minimising the use of materials, including a reduction in surface area, that may release utilisable carbon {which bacteria requires to grow} and by designs that do not leave residual volumes of water and will withstand a higher level of chemical and heat disinfection.”

It adds: “If the evidence of a connection between contamination and biofilm build-up is seen as persuasive then biofilm suppression may be a relevant factor. This has implications for the design and choice of materials used in tap construction and pipework fabrication.”

Manufacturers should be encouraged to seek alternative designs that reduce the risk by minimising the use of materials, including a reduction in surface area, that may release utilisable carbon and by designs that do not leave residual volumes of water and will withstand a higher level of chemical and heat disinfection

The working group also explored the impact of control measures such as UV water treatment, high-temperature flushing, and chlorination, finding that while there was evidence they had an impact on the presence of bacteria, their long-term success rate was largely unknown. It did, however, find that, in a large number of reported cases of Pseudomonas the colonisation occurred within the last 1.5-2m of the plumbing system nearest to the tap outlet and rarely extended beyond 1m from the tap. Additionally the key problems seem to stem from residual water present within the pipework when the tap was closed.

Responding to the findings, manufacturers involved in the research warned against a knee-jerk reaction amid fears that an increase in biocidal treatment of water systems and tap outlets could damage internal components and lead to rough surfaces forming, which could actually aid biofilm proliferation. Instead they are calling for trials to be undertaken before any major design changes or additional infection control measures are agreed.

The report does make some recommendations for improvements, however. These include the need for:

  • Further evaluation by the National Institute for Clinical Excellence (NICE) and academic institutions of the evidence base with a view to the creation of a new care standard on water quality and the protection of patients against infection
  • Additional evidence gathering to establish how common Pseudomonas contamination is
  • A specific policy document supported by a brief guidance package for regulators
  • The provision of a Top 10 Tips document for estates and facilities managers
  • A national survey of Pseudomonas prevalence
  • The development of a sampling and recording protocol for the routine monitoring of water systems
  • Commissioning of laboratory-based controlled research studies further exploring the relationship between Pseudomonas contamination and tap design, including materials, surfaces, water temperature and flushing regimes etc
  • A revision of Health Technical Memorandum (HTM) 04-01: The Control of Legionella, hygiene, ‘safe’ hot water, cold water and water drinking systems to include a wider focus on water quality

Additional work will now be carried out in line with the recommendations, with the publication of the updated HTM expected in March 2013.

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