Legionnaires disease Risk assessment outbreak investigation and control
Legionnaires’ disease: Risk assessment, outbreak investigation and control Session 7: Problems with Hospitals and Health Care ECDC, 2012
Problems with Hospitals and Health Care General Matters Hospitals and health care facilities - settings for the care and treatment of persons with ill health or the elderly. Higher risk of infection and case fatality rate Complex water systems • • • Complex buildings and water supply systems Water - potable and hygiene/cleaning Water - used as ice for patients Cooling towers - for air conditioning Hydrotherapy pools - for treatment
Problems with Hospitals and Health Care Cluster of cases linked to a hospital. Cases epidemiologically linked to hospital. Several observations were made based on a site visit.
Problems with Hospitals and Health Care Case study: Hospital A Part 1 • • New wing has been added on to an old hospital (old building circa 1900) Water system was filled and pressure tested in June and then disinfected by the contractors. Actually handed over to hospital management - August Not fully occupied until December. Supposedly built to “Standard Design” and supposedly with tested and approved materials. 5 months later positive Legionella tests from several sites around the system. + 1 month later had a case linked to hospital (patient recovered). Followed by chlorination and “negative tests”.
Temperature of cold water entering the building Designers had assumed mains intake @ 8 -12 ºC In fact nearer to 18 -20 ºC Solar reflective panels over mechanical service pipes fitted after hospital linked to first incident.
Basic water system design in new wing Ambient temp >34 ºC Roof tank Over capacity Riser steam + HCW >25ºC >50ºC >25ºC 49ºC >24ºC 46ºC >22ºC 34ºC Incoming mains UV Plant room >34 ºC 40 K storage tank potable
UV on supply as it enters building before storage UV units Installed prior to the cold water storage tanks Is this a problem?
Riser cupboard for mechanical services Mechanical Services in riser i. e. steam, DCWS. DHWS flow and returns, drinking water pipes in same conduit insufficient insulation to prevent heat / loss gain (riser 36 ºC). Excessive build-up of heat
No treatment until after first case Chlorine dioxide specified in original specification. But not installed until after the first incident.
When the panels are taken off from under the sinks. This is what you find - flexible hoses What are the risks? What should you do?
Hospital A part 2 4 months later - case 2 ( Fatal ) • Legionella in H&CW outlets. • Further testing revealed 42% outlets L. pneumophila Sg 1 +ve (>10 cfu/L) • 31% of outlets 102 -104 cfu/L L. pneumophila. What actions would you take?
The bay where the second patient stayed in Pipework in the old part of the building What would you advise here?
Reference lab report that L. pneumophila serogroup from hot water system matches patient isolate • System pasteurised, • Cl. O 2 increased to 3 mg/l, • Point of use filters installed in high risk areas.
Overall failures contributing to death of patient. • • Presence of dead legs Cold water at >30°C! Hot water <50°C on several loops Storage tanks in plant room Chlorine dioxide plant specified in design but not installed Storage Tanks oversized (owners changed mind over design) Flexible fittings -imported from China; not comply with Water Fittings Regulations, failed BS 6920 tests for ability to support microbial growth.
What must they do to open the ward Risk assessment Engineering works - remove dead legs. Systems in place for managing system: • Showerhead de-scaled and chlorinated. • Flushing programme maintained in rooms not used frequently. Chlorine dioxide levels raised & monitored at the outlets. Temperature profiling of whole system. Risk based sampling programme - monitor the system. Training of staff. Management.
Acknowledgements The creation of this training material was commissioned in 2010 by ECDC to Health Protection Agency (UK) and the University of Chester (UK) with the direct involvement of Louise Brown, Janice Gidman, Emma Gilgunn-Jones, Ian Hall (on behalf of the ECDC Legionnaires Disease Outbreak Toolbox Development Group), Tim Harrison, Rob Johnston, Carol Joseph, Sandra Lai, John Lee, Falguni Naik, Nick Phin, Michelle Rivett, and Susanne Surman-Lee. The revision and update of this training material was commissioned in 2017 by ECDC to Transmissible (NL) with the direct involvement of Arnold Bosman and Kassiani Mellou. 16
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