13-Feb-2012

Special report: Pseudomonas in hospitals

Abstract

Following the death of three babies in a neonatal intensive care unit in Northern Ireland, industry experts advise hospital trusts on how to reduce the risk of Pseudomonas bacteria in water supplies

Hospitals are stepping up infection control measures following the Pseudomonas outbreak in Northern Ireland

As health chiefs in Northern Ireland promise to leave no stone unturned in their investigation into the outbreak of Pseudomonas that killed three babies in a neonatal maternity unit, ministers in England have issued their own warning.

This week the Department of Health’s chief medical officer and scientific advisor, Professor Dame Sally Davies, published updated advice to assist health providers in preventing and controlling the superbug in special care units.

She said: “It is important the NHS takes all the necessary precautions to minimise the risk of contamination with Pseudomonas. aeruginosa bacteria, which can cause significant infections in very sick patients.

“The guidance we are issuing today reminds healthcare providers of the importance of high standards of infection control. It also provides them with helpful advice on best practice to prevent Pseudomonas in specialist care units, and gives clear and concise information on how to manage the risks.

“Health departments across the UK have worked together to produce guidance, and we will continue to keep it under review.”

The publication follows the deaths of three babies at the Royal Jubilee Maternity Hospital. They were all found to have contracted Pseudomonas , which was later traced to taps on the ward.

Since the first infant tested positive, a total of seven youngsters at the hospital have been found to be infected with the bacteria. A further six have confirmed Pseudomonas colonisation, which means the bacteria has been found on their skin or in secretions, but does not necessarily mean they have an infection. In addition, six other babies in neonatal units elsewhere in Northern Ireland also have confirmed colonisation. They are at units in Altnagelvin, Craigavon and Antrim.

Last week, Northern Ireland Health Minister, Edwin Poots, this week announced a ‘full and rigorous’ investigation into the outbreak. The probe will be chaired by Professor Patricia Ann Troop, former chief executive of the Health Protection Agency (HPA), and will be facilitated by the Regulation and Quality Improvement Authority (RQIA). It will investigate the reasons for the outbreak, the actions taken, and any lessons that can be learned. These areas for improvement are expected to include the development of updated guidance on water treatment and monitoring practices in healthcare settings.

In England, the advice covers best practice for handwashing and risk assessment. For handwashing it states:

  • Only use the hand wash stations for hand washing
  • Do not dispose of body fluids at the hand wash station
  • Do not wash any patient equipment in hand wash basins
  • Do not use basins for storing used equipment awaiting decontamination
  • Wash patients on augmented care units with water from outlets demonstrated to be safe through water sampling and risk assessment
  • Use all hand wash stations regularly
  • Flush taps regularly, either automatically or manually, and keep a record of when they were flushed
  • Report any problems to the infection prevention and control team
  • Do not locate alcohol gel dispensers at hand wash stations
  • Use pre-filled single-use bottles for alcohol-based handrubs or cleaning solutions
  • Ensure all staff are properly training

Hand hygiene is key to preventing the spread of Pseudomonas

Advice on risk assessment includes:

  • Set up a water safety group to develop an action plan for each trust
  • Develop separate risk assessments for Legionnaires and Pseudomonas
  • Ensure correct clean and dirty separation is maintained
  • Ensure taps and thermostatic mixing valves have been commissioned and routinely validated according to the manufacturer’s instructions

About Pseudomonas

What is it?

Pseudomonas is a genus of gamma proteobacteria, belonging to the larger family of Pseudomonads. It is widely found in soil and stagnant water and can infect humans and plants. There are more than 140 known species and almost all are saprophytic, that is they obtain the nutrients they need to survive from non-living organic matter, usually dead and decaying plant or animal matter.

The bugs do not usually cause illness in healthy people, but are ‘opportunistic’, causing serious infection when a person’s normal defences are weakened. This means they can pose a major threat to the most-vulnerable hospital patients, most commonly, as in the recent cases, intensive care patients and those with compromised immunity, including babies in neonatal units, burns patients and those with cancer.

How does it affect humans?

The severity and type of illness or infection caused usually depends on its route into the body. If it enters lung tissue, for example in a cystic fibrosis patient, it can cause a form of pneumonia that can be life-threatening. Infection through a wound on the skin or a burn can lead to extensive soft tissue damage or even septic shock, and, if the bacteria get into the gastro-intestinal system of a patient, they can cause necrotising enterocolitis, which can again cause serious damage to body tissue. This is the form most commonly found among premature babies.

They also occasionally contaminate refrigerated blood products which, when transfused into a patient, may cause endotoxic shock.

The Health Protection Agency says infection rates are pretty steady, with between 3,700 and 4,000 verified cases every year. Nine out of 10 of these are caused by the Pseudomonas. Aeruginosa strain, which was behind the recent outbreak in Northern Ireland.

How does it spread?

The most common route to patients is through medical equipment, particularly plastic or rubber catheters or feeding tubes, or contaminated hands. Good hand hygiene is therefore vital.

Pseudomonas bacteria also thrive 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 which 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.

Once in a water system, the bugs grow rapidly, creating a sticky film on pipework. This protects and harbours them and allows them to quickly multiply and take hold. It is these so-called sticky bio-films that can affect the drinking water, giving it a strange taste and appearance.

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.

How is it treated?

Patients found to be infected need immediate treatment. This is usually through antibiotic therapy, although the bacteria appear to have an inbuilt resistance to some antibiotics, as well as the ability to mutate into new, even more resistant forms.

Where the water supply itself is concerned, there should be a two-pronged approach; the first to prevent colonisation through regular maintenance and flushing of the system. This includes ensuring water is not allowed to stagnate and that cold water pipes and tanks, in particular, are regularly maintained, cleaned and disinfected.

The second mode of attack is to speedily treat any outbreaks once detected. Methods include continuous dosing of systems with chlorine dioxide, the installation on silver-copper ionisation equipment, and the use of UV and ozone.

All you need to know at a glance:

  • Pseudomonas growth is often directly related to the growth of Legionella in water systems
  • The bacteria produce a biofilm on pipework, which provides protection for the harmful bacteria and allows them to multiply. This slime also makes it more difficult to remove them
  • Risk assessments should be carried out regularly and water systems reviewed every two years by an expert water treatment company
  • Deadlegs and oversized water tanks should be removed for the system to minimise the risk of growth of bacteria
  • Regular flushing of the water system will prevent stagnation and the development of biofilm
  • A sampling regimen should be introduced, comparing levels of bacteria at the incoming mains supply to those from elsewhere throughout the building
  • Estates and facilities managers should adhere to the guidelines set out in AcoP L8 and HTM 04-01
  • Cold water systems should not be allowed to stagnate and tanks should be maintained, cleaned and disinfected regularly
  • Treatments include continuous dosing of the water system with chlorine dioxide, the installation of silver-copper ionisation equipment and the use of UV and ozone

Expert comment: How to tackle Pseudomonas in hospitals

The tragedy in Northern Ireland has put the spotlight firmly on the actions of hospital estates and facilities managers. They will now be facing increased pressure, both to test their own systems to ensure they are free from bugs, and to put in place robust treatment plans should they detect any bacteria.

Here, Jill Cooper, group microbiologist at B&V Water Treatment, explains the challenges they face and the options EFM professionals have in terms of preventing and treating water systems.

“The first thing that should be considered when preventing the growth of Pseudomonas species in water systems is that, in many cases, the Pseudomonas growth is directly related to Legionella growth, and similar treatment regimens should be used for the control of both.

Pseudomonas species are widely present in the environment and in many cases will be present in low numbers in the incoming mains supply to healthcare premises. The majority of species are not harmful to humans, but Pseudomonas. aeruginosa can cause numerous problems in immune-suppressed patients, including wound, ear and respiratory infections.

Pseudomonas growth is directly related to Legionella growth, and similar treatment regimens should be used for the control of both

Pseudomonas species can cause problems within water systems as they produce biofilm on surfaces. Biofilm is a layer of slime such as that you would find on a pebble in a stream. Obviously a biofilm layer on a pebble is not a problem, but when this is present on the pipework of a water system it protects and harbours harmful bacteria such as Pseudomonas and Legionella and is difficult to remove.

“Preventing the growth of Pseudomonas species and Legionella bacteria within water systems requires similar and relatively straightforward procedures.

“All healthcare premises should have a Legionella risk assessment and regular review every two years as part of their control programme. This should be carried out by a reputable water treatment company, which will have risk assessors with specific training and experience in conducting such investigations. The risk assessment will primarily look at the risk associated with the development of Legionella bacteria within the water system, but the remedial measures recommended will also pinpoint ways in which Pseudomonas growth within the system can be minimised.

Preventing the growth of Pseudomonas species and Legionella bacteria within water systems requires similar and relatively straightforward procedures

“Actions such as the removal of unused pipework (deadlegs), oversized water tanks and so on are actions which can be taken to minimise the risk of Pseudomonas growth. A quality risk assessment will also recommend a flushing regimen that will prevent stagnation of the water within pipework and minimise the development of biofilm containing Pseudomonas species.

“Such a risk assessment will also generally recommend a microbiological sampling regimen, which may include sampling for Pseudomonas species. If a regimen is implemented, it is very important to sample the incoming mains so that any results obtained throughout the wider water system can be compared with incoming levels. If samples are found with much higher levels of Pseudomonas within the premises than those present in the incoming mains, it is clear that conditions within the system are such that growth of Pseudomonas species is supported. It is also likely that a biofilm is present.

Actions such as the removal of unused pipework (deadlegs), oversized water tanks and so on are actions which can be taken to minimise the risk of Pseudomonas growth

“Such a risk assessment will consider all aspects of the water system including taps, showers, water tanks and strainers etc, looking at their suitability for use, i.e. their compliance with Water Supply (Water Fittings) Regulations 1999 and any associated risks.

“The guidelines on which a Legionella risk assessment are based can be found in ACoP L8 and the standard for healthcare premises Health Technical Memorandum 04-01 (HTM 04-01). Following the guidelines outlined in these two standards will go a huge way to minimising the proliferation of Pseudomonas bacteria within the water systems of healthcare premises.

“One of the main differences between Legionella species and Pseudomonas species is the temperature range of growth. A Legionella risk assessment will recommend a temperature monitoring regimen is implemented in line with the temperatures at which Legionella growth is minimised. For healthcare premises the temperatures for hot and cold water systems are specified in the HTM 04-01. Legionella species grow very slowly, if at all, below 20°c and are killed at elevated temperatures above 50°c. Pseudomonas species will grow down to 5°c and their growth in cold water systems can therefore be more of a problem. To minimise the risk of Pseudomonas it is critical to ensure there is no stagnation of the cold water system and that cold water tanks are maintained, cleaned and disinfected as necessary. Your water treatment supplier will advise on and carry out maintenance and cleaning of these systems.

To minimise the risk of Pseudomonas it is critical to ensure there is no stagnation of the cold water system and that cold water tanks are maintained, cleaned and disinfected as necessary

“Another significant difference between Legionella and Pseudomonas is the route of infection. Inhalation of very small droplets of water is the single root cause for the development of Legionnelosis (Legionnaires Disease). Pseudomonas infection can be transferred from person to person and via surfaces etc, which means that standard good hygiene practises to prevent cross contamination within a healthcare setting are essential.

“The first line of defence against Pseudomonas colonisation and proliferation within the system should be considered as everything covered by the Legionella risk assessment remedial actions and monitoring regimen. If all remedial actions have been completed and all on-going monitoring, such as flushing and temperature controls, are maintained and the problem persists it may be necessary to implement a chemical dosing regimen to the water system on site.

The incident at Belfast has given everybody in the healthcare industry a stark reminder of the importance of considering every aspect of microbiological control, including Pseudomonas, within water systems

“There are a limited number of methods generally used to treat these problematic water systems. Standard treatments include continuous dosing of the water system with chlorine dioxide, the installation of silver-copper ionisation equipment and, to a limited extent, the use of UV and ozone. Point-of-use filters can also be used to reduce risk, but do not, in any way, address any underlying microbiological problems. The type of treatment used is generally tailored to the specific requirements of a site.

“A good water treatment provider will be able to advise on all aspects of microbiological control within water systems in healthcare premises. The incident at Belfast has given everybody in the healthcare industry a stark reminder of the importance of considering every aspect of microbiological control, including Pseudomonas, within water systems.”

On the frontline: The battle commences

The NHS is currently in late-stage talks with B&V Water over the potential impact its new product, Absulox, could have in hospitals and healthcare buildings across the UK.

Tom Pellereau is the brains behind Absulox, a new water treatment product from B&V Water

Designed specifically to kill water-borne microbes including Pseudomonas and Legionella, the treatment and disinfectant product uses the active ingredient, hypochlorous acid, which is found in the human body’s immune system and is used to fight infection. This means it is non damaging to human tissue.

In trials, the substance has been found to eliminate pathogens within seconds. It can also help to maintain pipework, ensuring bugs do not return once eradicated.

B&V’s head of product development, Richard Sinden, said: “Absulox is going to have major ramifications as a new weapon in the fight against Pseudomonas and Legionella and is therefore potentially life-saving technology.”

Tom Pellereau, star of the TV show, The Apprentice, and the man behind the creation of the product, added: “This has the ability to kill bacteria fast, safely and when in situ. It provides a new weapon in the fight against deadly viruses.”

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