ProEconomy’s Orca system has never failed to control Legionella in a client’s premises.
Legionella Control Case Studies
- Basildon University Hospital
Basildon University Hospital
Background: This case study for Basildon Hospital presents data from before and after using a copper and silver ionisation (CSI) system, comprising 99.99% copper and 99.99% silver electrodes installed as a replacement to a failing chlorine dioxide system for Legionella control. The CSI system was used in conjunction with the existing temperature regime and was installed upstream of the water storage tanks to allow adequate build-up of copper and silver in tanks so that good levels were available for distribution to outlets.
Sampling: Samples were taken monthly and analysed for Legionella, by the culture method, and for copper and silver by Inductively Coupled Plasma-Optical Emission Spectroscopy/Mass Spectrometry over a four-year period. Temperature was also measured.
Results: Table 1 shows the results for Legionella counts and water temperature before the CSI was installed. The highest count was observed in the cold water supply to a Thermostatic Mixing Valve (TMV) at 19.6 °C. This shows that keeping cold water temperatures below 20 °C at outlets did not control L. pneumophila s1 at this outlet. The hot water temperature recorded (52.0–59.4 °C) showed the difficulty of keeping hot water temperatures above 55 °C.
Table 1 – Pre-commissioning Results: Legionella spp. and water temperature (August 2011)
Sample description Temp ºC Legionella Cfu/L Basin Hot TMV 54.2 10000 s1; 10000 s2-14 Basin Cold TMV 18.3 ND Shower Hot TMV 59.4 18000 s1; 72000 s2-14 R13 Bath Hot TMV 57.7 10000 s1; 20000 s2-14 R13 Bath Cold TMV 19.3 ND R13 Basin Hot TMV 56.5 1500 np R13 Basin Cold TMV 19.7 ND R6 Basin Hot TMV 52.0 36000 s1; 54000 s2-14 R6 Basin Cold TMV 19.6 290000 s1 R6 Basin en suite Hot TMV 52.1 10000 s2-14 R6 Basin en suite Cold TMV 19.1 ND R6 shower en suite Hot TMV 53.5 ND Shower en suite MT TMV 41.7 ND Toilet room Hot MT TMV 58.1 ND
ND=not detected (detection limit=20 cfu/L); np=Legionella non-pneumophila; s1= Legionella pneumophila serogroup 1; s2-14= Legionella pneumophila serogroup 2-14; TMV=thermostatically-controlled mixing valve.
Figure 1 – Number of samples tested and number and percentages of positive samples for Legionella between Aug 2011 and April 2015, Basildon Hospital.
Figure 1 shows the number of samples tested, number and percentage positives for Legionella. The CSI system was installed in October 2011 and initial problems occurred during the commissioning stage up to four months after commissioning. These initial problems (deadlegs, deadends and low-use outlets) were rectified Legionella was controlled consistently, with only low positives counts occurrences in 2013. Monthly monitoring of outlets has showed no positive result for 15 months, between January 2014 and April 2015.
Conclusion: It was concluded that Legionella could not be effectively controlled using a temperature regime alone, even when temperature was maintained at below 20 °C or at above 55 °C; and that copper and silver ionisation used in conjunction with the temperature system already in place was effective for Legionella control at this hospital. Legionella is still being controlled successfully at Basildon Hospital since the last data shown in the graph.
As per ProEconomy usual service when providing their Orca system, the system was regularly monitored to ensure the required concentration of ions was maintained, so that potential Legionella sources, such as build-up of biofilms in rubber-lined hoses, were dealt with as soon as detected.
Testimonial taken from HSE led Independent Review of hospitals using Copper and Silver Ionisation
‘Despite capital investment of around £2million…Legionella continued to be a problem’
‘Despite dosing Chlorine Dioxide at elevated levels (2ppm) and also achieving good levels of temperature control, 3 further cases….were diagnosed in 2011 with one death.’
There have been ‘zero positive samples reported since the beginning of October 2012 [when the Orca system was installed]…the hospitals water system is now under control.’
David Hastings, Estates Manager at Basildon University Hospital.
- Birmingham Heartlands Hospital
Birmingham Heartlands Hospital
Controlling Legionella in a UK hospital using copper and silver ionisation
Birmingham Heartlands is a 700-bed hospital which has a mixed-age infrastructure with a variety of materials and systems. Before 2007 the hospital used a temperature regime fully compliant with HSE and DoH guidelines for controlling Legionella. When they introduced testing, however, they found that Legionella was present.
The first step taken to address the problem was to dose the whole site with sodium hypochlorite. They were keen to get away from using chemicals, however, for COSHH and cost reasons. Furthermore, it wasn’t effective at eradicating Legionella or biofilm. Accordingly, alternative methods were examined, including copper and silver ionisation. Hospitals using the ProEconomy Orca system were visited, and all said it was efficient and cost-effective with a good support service. The final choice of ProEconomy’s system was based on cost, the fact that it used separate copper and silver electrodes rather than an alloy, and the documentation which gave evidence that control measures were working.
An 18-pod Orca system was installed in October 2007. The temperature regime was maintained. Soon after implementation a run of positive samples was traced back to flexible hoses, removal of which solved the problem. There was some concern initially over the effects on the RO unit in dialysis, but tests showed that metal levels on the secondary supply side were all within guidelines. Pre-installation, 50 samples had returned 21 positive results, ranging from 100cfu/L to 9,800cfu/L. Within a month levels had fallen to only five positives from these 21 sites, ranging from 100cfu/L to 2000cfu/L, and within six months this had dropped to zero. Results for samples taken over a seven-year period are shown in Figure 1. After commissioning of the Orca system in 2009 and up to December 2016, only 11 samples were positive for Legionella out of 1253 samples tested.
Fig 1 - Legionella results for Birmingham Heartlands Hospital between 2011 and 2016.
ProEconomy undertakes monthly sampling with analysis at an independent laboratory to determine the presence of Legionella, copper and silver concentrations, temperature and TVC. The hospital selects 21 sampling outlets per month, usually identified as being at risk of contamination, e.g. low use, blended, etc. These are rotated frequently, depending on results, to ensure maximum coverage. Low levels of copper and silver are used as a diagnostic tool to fault-find on the system. Any issues are few and far between, and down to local engineering problems.
Highlights from Hospital Times interview with Tony Wright – Estates Manager at Heartlands Hospital.
“Prior to installing the [Orca] copper and silver ionisation system we took pre-commission control samples at 50 outlets across the site in May 2007 to establish our level of contamination. We sampled a mix of outlet types and areas - clinical, acute clinical and non-care’
‘These initial 50 control samples returned 21 positive results ranging from 100cfu/l to 9,800cfu/l’
‘’Once the copper and silver ionisation treatment plant was enabled we re-sampled the same 21 positive sites in early October 2007. Within a month of installation, the system was already proving to be very effective. From the 21 sites we returned five positive samples, ranging from 100cfu/l to 2,000cfu/l. The results continued to improve and by the March 2008 all the samples we were taking were completely clean. A further advantage of reduced TVC levels were also realised in areas previously known to have high levels.’
“It works. You can’t put a price on that when it’s patient safety. With ProEconomy’s copper silver ionisation system there are no health and safety issues - no problems with COSHH. Other solutions we looked at were fraught with issues.
“ProEconomy’s system is a known quality - there’s no the guesswork. There was before. The implication then was ‘don’t test because you’ll find it’. Now we’re completely confident. We now have the documentation and records to demonstrate that the control measures employed are an effective “closed loop” control with no guesswork!
“The system has a number of other advantages. It supplements our existing temperature control regime. Due to the change in the level control mechanism, the site break tank contents are now turned over regularly, rather than just being topped up. The copper and silver levels are used as an indicator to ensure flushing regime is effective, as water flow is required to distribute and maintain the required levels.
“It’s a proactive system and we’re a proactive trust, working with proactive ProEconomy.”
“We share Best Practice across the trust, ProEconomy’s solution was so successful at Heartlands that within seven months it was installed at Solihull Hospital and Good Hope Hospital."
“In the nine years we’ve been with ProEconomy we’ve never had a reason to question the service. We’ve always received what we’ve asked for.”
Tony Wright, estates manager Birmingham Heartlands Hospital
- Solihull Hospital
Controlling pathogens in a UK hospital using copper and silver ionisation
This 350-bed hospital is a smaller site with newer buildings than Birmingham Heartlands. As was the case with Heartlands, a temperature regime was applied as the sole Legionella control measure. This proved difficult to maintain. Mixing valves had to be fitted and rubber lined flexible hoses and rubber fittings were attached to several outlets. Water stagnation was also possible due to poor use of outlets and ward closures – ideal conditions for Legionella proliferation.
Table 1 – Initial Pre-Orca Analyses Results – Solihull Hospital – 10/01/2008
Outlets Legionella counts (cfu/L) Water Temperature (°C) Outlet 1-mixed 0 28 Outlet 2-hot 0 57 Outlet 3-cold 100 13 Outlet 4-mixed 2200 14 Outlet 5-mixed 100 45 Outlet 6-hot 0 55 Outlet 7-hot 0 15 Outlet 8-mixed 100 18 Outlet 9-hot 0 41 Outlet 10-cold 0 13 Outlet 11-hot 0 57 Outlet 12-cold 0 12 Outlet 13-hot 0 53 Outlet 14-cold 0 11 Outlet 15-hot 0 54 Outlet 16-cold 0 12 Outlet 17-mixed 0 39 Outlet 18-mixed 0 36 Outlet 19-mixed 0 44 Outlet 20-hot 0 56 Outlet 21-cold 0 14 Outlet 22-mixed 0 38 Outlet 23-hot 0 55 Outlet 24-cold 0 12 Outlet 25-mixed 5900 32 Outlet 26-mixed 100 41 Outlet 27-hot 0 59 Outlet 28-cold 200 12 Outlet 29-hot 0 57 Outlet 30-cold 0 11
Following the success of the Orca at Heartlands, one copper and silver ionization system, with eight copper and four silver electrode chambers, was installed in January 2008. Prior to installation 30 outlets were sampled, including hot, cold and blended outlets. Table 1 shows the results for Legionella and water temperature of the outlets tested. It can be observed that counts ranged from 100 cfu/L to 5,900 cfu/L and that seven out of 30 outlets (23%) tested positive for Legionella, including four outlets where water temperature was below 20 °C. One month later, these seven outlets were resampled, together with a further eight outlets identified as being at risk. Only one, an original positive, showed the presence of Legionella, and even here the level had fallen from 2,200 cfu/L to 200 cfu/L.
Results for the last six years demonstrate the level of control exerted by the Orca system (Figure 1). There were occasional low counts (100-300 cfu/L non-pneumophila) between 2011 and 2013, with one 900 cfu/L np count in April 2012 and one 600 cfu s2-14 in April 2014. No Legionella has been detected for the past 3 years (April 2014 - April 2017).
Figure 1 - Legionella results for Solihull between 2011 and 2017
In 2013 Solihull asked ProEconomy to test for the presence of Pseudomonas aeruginosa. Of the 357 samples taken in the past four years, only six were positive for P. aeruginosa (1.7%).
The results for P. aeruginosa have shown that between July 2013 and June 2017 there were only 6 positives for P. aeruginosa, out of 357 samples tested (1.7%), with counts of 2 to 9 cfu/100 ml and one count of 100 cfu/ml (Table 2).
Table 2 – Solihull Hospital P. aeruginosa results - 1st January 2012-31st December 2013
Sample Date Total Samples taken Pseudomonas aeruginosa cfu/100ml Percent Positives (%) 05/07/2013 30 0 0.0 20/10/2013 27 0 0.0 03/11/2013 35 2 5.7 31/01/2016 32 0 0.0 07/02/2016 23 0 0.0 21/02/2016 34 0 0.0 05/09/2016 5 0 0.0 25/09/1916 81 2 2.5 16/10/2016 4 1 25.0 06/11/2016 2 0 0.0 08/05/2017 5 0 0.0 14/05/2017 75 1 1.3 08/06/2017 4 0 0.0 Total 357 6 1.7
ProEconomy undertakes monthly sampling at 21 outlets at Solihull, with analysis being carried out at an independent laboratory to determine the presence of Legionella, copper and silver concentrations, temperature and TVC. Pseudomonas aeruginosa tests are carried out every six months.
- University Hospitals Bristol NHS Foundation Trust
University Hospitals Bristol NHS Foundation Trust
Controlling waterborne pathogens in a UK hospital using copper and silver ionisation.
University Hospitals Bristol NHS Foundation Trust has Orca systems fitted in seven of its hospitals, beginning with the King Edward Hospital in 2005, and used in conjunction with temperature control.
The Orca system is used in conjunction with the Temperature Control Regime.
The Trust has found the Orca system to be very simple to use. Their experience has been that any issues that have arisen have been dealt with promptly by ProEconomy, who have put additional resources in place to resolve complex or unique problems. Tim Evans, the company engineer assigned to the hospitals, has proven to be very conscientious, good at problem solving and prepared to come on site all hours of the day to reduce impact on clinical operations.
Highlights from article in Hospital Bulletin with Ben Gardiner, Estates Officer at University Bristol NHS Foundation Trust.
Why did you choose Copper and Silver ionisation?
- No chemicals were being used on site, so removing any COSHH issues;
- The Orca system is relatively maintenance free, allowing valuable staff time to be used elsewhere;
- The biocidal effect is long lasting, which is useful for providing protection in infrequently used outlets;
- Using some other supplementary disinfection systems resulted in excessive corrosion.
Have you found the Orca Copper and Silver ionisation system to be effective?
This mode of disinfection has proved very effective on this precinct in aiding and controlling waterborne pathogens.
Would University Hospitals Bristol recommend the Orca system to others?
- Churchill Hospital
Background: The Churchill Hospital (part of the John Radcliffe, Oxfordshire) is a teaching hospital in Oxford, England. The hospital was established in 1942 and is primarily a centre for the treatment of cancer patients, with research and teaching facilities. It has 180 in-patient and 100 day care beds. The Orca Copper and Silver Ionisation system (CSI) system was installed at the Churchill Hospital in November 2014.
Sampling: Before the CSI system was activated, pre-commissioning samples were taken from 16 outlets identified as being at risk of Legionella contamination. After activation of the CSI system, samples were taken every month from 9 to 20 outlets that showed risk of Legionella contamination and were analysed for Legionella by the culture method and for copper and silver by Inductively Coupled Plasma-Optical Emission Spectroscopy/Mass Spectrometry (ICP-OES/MS), by UKAS accredited laboratories (ALcontrol and ALS Laboratories, UK). The number of outlets sampled was then reduced to 11 outlets, after ProEconomy was satisfied that Legionella was being controlled, and it was reduced to six outlets sampled monthly in the past year.
Results: The results of the pre-commissioning samples (November 2014) are shown in Figures 1 and 2. A total of nine of the 16 outlets tested showed the presence of Legionella pneumophilla SG2-14 with counts of 100 (2), 200, 300, 600 (2), 1300, 1400 and 5200 cfu/L. One outlet had flexible hoses and a large deadleg, which caused Legionella to persist there for longer than in other outlets. The number of outlets sampled was then reduced to 11 outlets, after ProEconomy was satisfied that Legionella was being controlled, and for the past year, six outlets are sampled monthly.
Legionella at counts above 100 cfu/L persisted in some outlets until April 2015 (Figure 1), due to flexible hoses and deadlegs. Since June 2015 (6 months after commissioning) Legionella has been controlled, with only three outlets showing low counts (100 cfu/L of mainly non-pneumophila). No Legionella has occurred in any of the tested outlets at Churchill Hospital after July 2016 (Figures 1 and 2).
Figure 1 - Legionella counts at eleven outlets
Figure 2 - Total number of samples taken per month, number of positives and percentage of Legionella positives.
Conclusion: There was enough evidence to show Legionella posed a real threat to the hospital. Legionella control using a CSI system was achieved from May 2015 and total Legionella eradication was achieved from August 2016 onwards. The system, like any other Legionella control system, must be monitored regularly so that any problem outlet is quickly detected and dealt with. Legionella has been totally eradicated from the Churchill Hospital for about a year now and as a result, ProEconomy is now providing Legionella control to the whole of the John Radcliffe Hospital.
Testimonial: In an interview with Hospital Times magazine, Claire Hennessey, Head of Operational Estates for Oxford University Hospitals NHS Foundation Trust, had the following to say about their experience with the Orca system: “We started with an installation at the head and neck ward at the Churchill Hospital, where we had the showers out of use and where calorifiers giving us temperature control issues. Depending on how the system worked, it would be a showcase of what we could introduce to the bigger site at John Radcliffe. The result was amazing. In the pre-sample, before the ProEconomy system went in, we had nine positives out of 16 sites sampled. In the first month sampling, after the installation, we were down to just one positive. That one positive stayed for a while. The system allowed us to see that and we evidenced that the outlet concerned was used very infrequently.”
- Devon Centre for Women’s Health
Devon Centre for Women’s Health
Background: This case study reports the application of a copper and silver ionisation (CSI) system for the long-term control of Legionella in a health centre that had previously tried to control Legionella using the temperature regime but had consistently detected Legionella contamination at outlets.
Setting: The building is a purpose-built extension of a large district hospital in Devon, UK, covering over 9000 m2 serving a catchment of 350,000 and employing over 400 staff. Most rooms have en-suite facilities and washrooms are provided between the delivery rooms.
The hospital installed the Orca CSI system when, following occupation of the building in June 2007, water analysis results confirmed the presence of L. pneumophila serogroup 1 in the blended water system in samples taken on the 28th November 2007 and 30th January 2008. The Orca CSI system from ProEconomy Ltd was commissioned on the 04th February 2008.
Orca System Installation and Continued Sampling: The Orca CSI system (99.99% pure copper and 99.99% pure silver electrodes) was installed in February 2008, prior to two 20,000-L storage tanks to allow adequate build-up of copper and silver levels so that good levels of copper and silver were available at outlets. Flow regulating valves were installed in tanks, which are required by the Orca system, as these activate the system regularly and good levels of these ions are, therefore, released into the tanks. The water was heated by two steam generated calorifiers, each fitted with a shunt pump. The water was not softened, as the calcium carbonate (CaCO3) value of the water supply was low (91 mg/L CaCO3) indicating moderately soft water. A Southwest Water quality report was consulted, as certain parameters could influence the biocidal efficacy of the ionic copper and silver. The 12-month averages were: chloride 18.5 mg/L; conductivity 163 µS/cm; and manganese <2.3 µg/L. None of these values presented potential interference with the system’s biocidal efficacy. The average water pH value was 7.9 (Southwest Water Quality Report).
Water Sampling and Analyses
Before the CSI system was activated, pre-commissioning samples were taken from 20 outlets identified as being at risk of Legionella contamination. After activation of the CSI system, samples were taken every month from 10 outlets that showed risk of Legionella contamination and were analysed for Legionella by the culture method, for total viable bacteria (TVC) at 37 °C and at 22 °C by the culture method, and for copper and silver by Inductively Coupled Plasma-Optical Emission Spectroscopy/Mass Spectrometry (ICP-OES/MS), by UKAS accredited laboratories (RD&E NHS foundation Microbiology Laboratory and ALControl Laboratories, UK). The outlet points were rotated from June 2010 and Legionella was, therefore, monitored at 20 outlets.
The results of the pre-commissioning samples (04/02/2008) are shown in Table 1. Legionella (100 cfu/L) was found at one cold outlet and at three blended outlets (1100, 1200, and 500 cfu/L). A total of 21 outlets were tested, around 20%, therefore, were contaminated. The average Legionella count of the 21 outlets sampled was 138 ±77 cfu/L.
Table 1. Results from samples taken before commissioning of copper and silver ionisation system
Sample Point Temp. °C Silver mg/L Copper mg/L TVC at 37 °C day 2 cfu/ml TVC at 22 °C day 3 cfu/ml Legionella cfu/L Detection Limit = 100 APN58MT 35 0.004 0.034 9 4 ND APN49CT 16 <0.003 0.043 18 2 100 np APN49MT 39 <0.003 0.056 7 6 1100 np NE12CT 17 <0.003 0.035 8 8 ND NE46MT 34 <0.003 0.047 78 23 ND PE30CT 16 <0.003 0.069 6 4 ND DS82SH 34 <0.003 0.042 84 40 ND DS99HT 57 <0.003 0.063 0 0 ND DS55CT 20 <0.003 0.029 4 10 ND DS50MT 39 <0.003 0.044 0 2 ND ANC18CT 15 <0.003 0.037 22 8 ND ANC18MT 41 <0.003 0.054 69 12 ND ANC23MT Not Taken Not Taken Not Taken Not Taken Not Taken 1200 s1* ANC28CT 14 <0.003 0.109 23 6 ND Toilet Near 9CT 12 0.014 0.033 8 1 ND GW1MT 38 <0.003 0.057 57 8 ND GW25SH 41 <0.003 0.059 330 220 ND GW50MT 38 <0.003 0.058 24 6 500 np GW85MT 38 0.021 0.051 29 12 ND SO37SC 13 0.015 0.034 495 550 ND SO37SH 42 0.006 0.073 550 330 ND
MT = Mixer Tap, CT = Cold Tap, HT = Hot Tap, SH = Shower Hot, SC = Shower Cold, ND = Not Detected, TVC = Total Viable Count, np = Legionella non-pneumophila, s1 = Legionella pneumophila serogroup 1. * Analysed by the study hospital on the 30th January 2008.
The average water temperature recorded at cold water outlets was 16 ± 1 °C, which is within the limit advocated for the traditional temperature control regime of <20 °C. The temperature recorded at the contaminated cold water outlet was 16 ⁰C. The average temperature at the hot water outlets was 38 °C (± 2.5 °C). The temperatures recorded at the three contaminated hot water outlets were below 50 °C, because the water was blended to obtain safe (from scalding) hot water temperatures below 45 °C.
The average copper concentration before installation of the CSI system was 0.051 ± 0.004 mg/L, which is background copper from the copper pipes. The CSI system was activated on the 04th February 2008.
Table 2 shows analyses results for samples taken on the 6th March 2008, one month after the ionisation system installation. Samples were taken from the four outlets (APN49CT, APN49MT, ANC23MT and GW50MT) that were contaminated before the system activation and from six other outlets identified as being at risk of Legionella contamination (DS82SH, DS50MT, DS50CT, SO37SC, SO37S, and GW25SH). No Legionella were found in these samples, with silver levels of 0.039 to 0.115 mg/L.
Table 2 - Results from samples taken one month (March 2008) after commissioning of CSI system
Sample Point Temp. °C Silver mg/L Copper mg/L TVC at 37 °C day 2 cfu/ml TVC at 22 °C day 3 cfu/ml Legionella cfu/L Detection Limit = 100 DS82SH 41 0.039 0.155 0 0 ND DS50MT 42 0.043 0.156 0 0 ND DS50CT 10 0.083 0.183 0 0 ND APN49MT 40 0.045 0.162 1 2 ND APN49CT 10 0.092 0.199 2 13 ND ANC23MT 40 0.049 0.188 3 0 ND SO37SC 11 0.115 0.287 5 0 ND SO37SH 42 0.044 0.150 2 1 ND GW25SH 41 0.046 0.157 6 0 ND GW50MT 41 0.041 0.158 0 1 ND
MT = Mixer Tap, CT = Cold Tap, SH = Shower Hot, SC = Shower Cold, ND = Not Detected
Figure 1 shows average Legionella count for four outlets (SO37SH, APN49MT, DS82SH, DS50MT) that were sampled throughout the reporting time for this study, from pre-commission to the study end (4th Feb 2008 – 2nd July 2015). It can be observed that Legionella persisted at one blended outlet, APN49MT (set on hot), until June 2009, after which Legionella was not detected in any of the outlets tested up to May 2011 (Figure 1). Legionella np was detected in May 2011 in one outlet (APN49MT) at 600 cfu/L. This was suspected to be due to lack of flashing of the outlet and after that all outlets were flushed twice a week for 3 minutes, which increased the silver levels, resulting in Legionella control, as no Legionella was found at any outlets tested since, except for once in March 2012, at 100 cfu/L.
From June 2009, the copper side of the ionisation system was switched off, due to high phosphate levels in the mains water supply, which can potentially form precipitates with copper, resulting in discoloration of the water. Once the copper side was switched off, water discoloration disappeared suggesting it was due to the copper added by the ionisation system. Orthophosphate (1 - 2 mg/L) is added by water companies to minimise dissolution of lead from lead pipes.
Average copper levels in samples remained, however, around 0.2 mg/L until November 2011 (Figure 1), which was most likely residual copper from the ionisation treatment, to start with, and then copper leaching from copper pipes. However, copper levels reduced from the beginning of 2012 onwards.
The average silver level in samples taken monthly from all sampled outlets, from March 2008 to July 2015 was 0.037 mg/L (SD=0.012), which is within the Orca system recommended level (0.020-0.080 mg/L). The average copper level was 0.072 mg/L (SD=0.012) from 2012, which was solely copper that had leached from the copper pipes. For this health centre, therefore, no extra copper from ionisation was necessary for the control of Legionella, since control was achieved with copper leached from the copper pipes and silver from ionisation of solid silver bars.
The hot water temperatures recorded were all below 50 °C because of blending. The average hot and blended water temperatures recorded were 41 ± 0.3 °C and 10 ± 0.3 °C, respectively.
In hard water areas the release of copper and silver ions can be slowed down due to scale build-up on the electrodes, therefore, reducing ions release (Lin et al, 2011; Srivastava et al, 2011; Walker et al, 1997). This was minimised by using pure copper and silver electrodes and by switching the electrodes polarity, which cleared scale build up (Bedford, 2003).
Conclusion:There was enough evidence to show Legionella posed a real threat to the health centre evaluated in this study. Legionella control and eradication using a CSI system was achieved from April 2012 onwards at 20 outlets. The system, like any other Legionella control system, must be monitored regularly so that any problem outlet is quickly detected and dealt with. From the results of this study, it can be concluded that when silver concentration is maintained at outlets, at an average of 0.037 ± 0.012 mg/L, and only an average background copper level from existing copper pipework, of 0.072 ± 0.012 mg/L, is maintained, Legionella was effectively controlled at a range of water temperatures, including the 23-42ºC range, which is the optimum for Legionella growth.
Bedford BHM (2003). Toxicity of copper and silver. MSc Thesis, Cranfield University, UK.
Lin Y, Stout JE, Yu VL. (2011) Controlling Legionella in Hospital Drinking Water: An Evidence-Based Review of Disinfection Methods. Infection Control and Hospital Epidemiology 32:166-173.
Srivastava S, Colville A, Odgers M, Laskey L, Mann T. (2011) Royal Devon and Exeter NHS Foundation Trust. Controlling Legionella risk in a newly commissioned hospital building. Journal of Infection Prevention 12:11-16.
Walker JT, West AA, Morales M, Ives S, Pavey N. (1997) Controlling Legionella and biofouling using silver and copper ions: Fact of Fiction? Bioline 279-286.
- The John Radcliffe Hospital Oxford
The John Radcliffe Hospital Oxford
Background: The John Radcliffe Hospital (JR) is a large tertiary teaching hospital in Oxford, England. It is the main teaching hospital for Oxford University and Oxford Brookes University. As such, it is a well-developed centre of medical research.
Following the success of the Orca system operating at the Churchill Hospital, which is part of the John Radcliffe, a business case was presented by the JR Estates Manager to the trust board to install the copper and silver system at the other two John Radcliffe buildings (JR1 and JR2) to help eradicate the Legionella issues they were facing there.
Installation of the Orca: The Orca copper and silver ionisation system was installed at the JR in 2016. A KB2 system was installed overnight at JR1, the Women’s Centre, in May 2016. The system at JR2, the main hospital, was installed in September 2016, comprising a KB4 (24 pods serviced by 2 x KB3).
The neonatal intensive care unit has its own water supply and they were observing Legionella positives; therefore, one KB1 was installed at NICU as well to treat their separate water supply.
There was no need to isolate any of the services at any of the sites. The Orca system has now been in place for a whole year.
Sampling: Before the Orca system was activated, pre-commissioning samples were taken from outlets identified as being at risk of Legionella contamination, 50 outlets at JR1 and 100 outlets at JR2. After activation of the system, samples were taken monthly from outlets that showed risk of Legionella contamination; 22 to 27 outlets at JR1 and 48 to 61 at JR2. These were analysed for Legionella by the culture method and for copper and silver by Inductively Coupled Plasma-Optical Emission Spectroscopy/Mass Spectrometry (ICP-OES/MS), by UKAS accredited laboratories (ALControl and ALS Laboratories, UK).
Results: A total of 495 samples were collected from JR2 and 384 samples from JR1 since commissioning and the Legionella results for JR2, the main hospital, is shown in figure 1. It can be observed that Legionella was a problem at JR2. However, the Orca copper and silver ionisation system has reduced Legionella positives at affected outlets steadily over a year, from the highest level of 24 at pre-commissioning to 2 positive samples in September 2017.
Since January 2017, there has been only three low counts (100 to 200 cfu/L) Legionella positives at JR1, two in April and one in July.
With infection control on board, the hospital is ensuring personnel are educated on the need for flushing.
Fig 1 – Total samples, number of Legionella positives and percentage positives, John Radcliffe Hospital main block-JR2 (Aug 2016 - Sep 2017)
Conclusions: There was enough evidence to show Legionella posed a real threat to the hospital. Legionella control using the Orca system was achieved from January 2017 at JR1 and total Legionella counts have reduced steadily in the past year from 24 to 2 positive samples at JR2. The system, like any other Legionella control system, must be monitored regularly so that any low-use outlet is quickly detected and flushed regularly.
Customer testimonials: Environmental Estates Manager, Phil Mitchell, explained that “through the sampling and the low levels of copper and silver identified in certain areas, it was possible to establish which little used outlets were not being flushed. This allowed estates to report to the hospital infection control committee on the areas which were not being flushed.” The infection control team is very supportive and has worked with the estates department to get the areas to undertake their flushing, said Phil. They went to the departments and highlighted the risk to them of not flushing. As soon as a positive sample was detected, the outlet was taken out of use and put on a daily flushing regime, which is done in-house. The outlet goes back into use after three consecutive, clear results.
Phil added: “Now, for the last two months we’ve been clear, with no positives in the Women’s Centre.”
Claire Hennessey, Head of Operational Estates, has the following to say about the Orca system:
“It’s the first time, after 20-years in estates, I’ve come across a system that’s so effective in managing your water system. It’s a blessing!”