Hospital-acquired Legionnaires' disease usually originates in hospital water systems. Legionella bacteria not only persists in hot water tanks, it is often found in the biofilm through the entire water system.
Conditions within water systems that promote Legionella colonisation include water temperature, configuration and age of the hot water tank, and plumbing materials.
An estimated 10 to 15 thousand people contract Legionnaires' disease in the USA each year; 5 to 15% of these cases prove to be fatal. An additional unknown number are infected with Legionella bacterium and have mild symptoms or no illness at all. Additionally, Legionellosis is frequently misdiagnosed as common pneumonia.
The occurrence of Legionnaires’ disease, and subsequent fatality rates caused by nosocomial Legionellosis are much higher in hospitals and healthcare facilities than are observed elsewhere. In many parts of the world there is strong legislation to ensure that this entirely avoidable disease is prevented from coming into contact with high-risk members of the population.
In the US the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) recommends a Risk Minimization Plan for all healthcare facilities "to reduce the potential for organisational-acquired illness including managing pathogenic biological agents in cooling towers, domestic hot water, and other aerosolising water systems. The UK's Health and Safety Executive (HSE) also produce excellent guidance on the control and management of Legionella risks in their ACoP L8 Document.
Hospital-Acquired Legionnaires' Disease
"The risk of hospital-acquired Legionnaires' Disease can be minimised by control measures directed at the water distribution system. These include superheat-and-flush, copper/silver ionisation, ultraviolet light, instantaneous heating systems, and hyper-chlorination. Each of these disinfection methods is effective in the short-term, but long-term efficacy is difficult due to limitations associated with each method.
Because of its biocidal characteristics, chlorine dioxide (ClO2) is ideal for water hygiene. ClO2 has consistently been shown to be the best molecule for eradicating the causative organism of Legionnaires' disease. In the UK, the Building Services Research and Information Association (BSRIA) has recommended CIO2 as the best available technology for control of Legionella in hot and cold water systems.
Chlorine dioxide generated using an Accepta SafeOx generator system is effective in both short-term and long-term applications. It eliminates pathogens on initial application and then leaves a residual of CIO2 to prevent re-infection. In addition to Legionella and other bacteria, CIO2 also destroys biofilms so regrowth is significantly impeded. CIO2 is safe for plastic piping and exhibits no objectionable corrosive attack on copper piping.