PUBLIC HEALTH
INFORMATION
Issued by the Environmental Health Service of the Department of Health
Date 12/03/2003
Use and maintenance of ice machines for
Legionella control
As widely reported, in February 2003
there was a case of Legionnaires’ disease at the Royal Adelaide
Hospital. Legionella was isolated from the ice machine used by
the patient.
It is likely that
a high proportion of ice machines have the potential to grow
Legionella due to warmth generated from compressors promoting growth
of organisms in water lines within the machines. Despite this, ice
machines and use of ice are not considered as representing a high risk
to most people because in addition to the organisms being present
infection normally requires the production of aerosols leading to
inhalation of micro-droplets.
However, there have been a limited
number of reports in the published literature involving 4 cases of
legionellosis possibly associated with ice machines. The reports
indicate that the infections were in immunocompromised patients with 3
being from transplant wards while the other was ventilator dependent.
The mode of infection is assumed to be micro-aspiration from consumed
ice.
A protocol for
dealing with potential risks associated with use of ice machines has
been developed. The protocol requires that ice given to patients will be
subject to similar controls applied to other environmental conditions
(eg air) and food quality. Where high risk patients are provided with
increased protection from infection (HEPA filtered air, low bacteria
food etc), ice should not be provided from ice machines but should be
manufactured by freezing chlorinated cold water in freezers/fridges of
the type found in homes.
Water supplies
provided to rooms used by these high risk patients should also be
subject to more frequent monitoring (eg water temperature, free chlorine
residuals) to ensure safety.
Ice machines can be
used for other patients providing these machines are maintained
appropriately and kept clean. As a minimum, machines should be completely cleaned
on an annual basis. This should include flushing and cleaning of water
lines using a disinfectant solution (eg chlorine) and/or hot water
(above 65OC). Carbon filters should not be used on the inlets
to such machines.
If you require
further information please contact Peter Bond (telephone 8226-7157,
peter.bond@health.sa.gov.au)
of the Environmental Health Service.
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