105
But
Legionella
disease is not the onlybuildingwater system associated
problem. Other pathogens associated with building water systems that
are known to cause disease include
Acinetobacter
(Kohlenberg 2009),
Pseudomonas
(WRF2013)
Mycobacterium
(Steinert1998),
Stenotrophomonas
(Looney 2005),
Aspergillus
(Anaissie 2002),
Fusarium
(Anaissie 2001,
Short 2011) and from free-livingamoeba in treateddrinkingwater systems
(Thomas 2011).
TheHazards
Exposureofbuildingoccupantstomicrobialhazards(suchaspathogenic
bacteria), chemicalhazards (suchasdisinfectionby-products)andphysical
hazards (such as scalding from attempts to control hazards with thermal
eradication) often result fromprocessinganduseof thewater inbuildings.
Biofilms
The root cause of the problem inbuildingwater systems is communal
microorganisms living on surfaces, in deposits and in sediments. These
microbialcommunitiesarecalled“biofilms”.Theyaredynamic,adaptive,and
difficult to control. Whenbiofilmsbecome complexandmicrobiologically
diverse enough to include amoeba and other protist hosts, growth to
dangerously high levels of opportunistically pathogenic microorganisms
such as
Legionella
,
Pseudomonas
and
Mycobacterium
in building water
systems is often the result (WRF2013).
