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The bacteria of the genus
Legionella
are bacilli, pleomorphic, gram-
negative ones, measuring from 0.3 to 0.9 µm in diameter and 2 to 5 µm in
length; they are normally found in nature in aquatic environments such
as rivers, lakes and other reservoirs. Temperatures between 20 and 45 °C
favor the proliferation of the bacterium which apparently does not multiply
in environments with temperature inferior to 20 °C and higher than 50 °C
(FERREIRA 2002) (JOSEPH
Et al
2012).
The ecology and survival of the bacteria of the genus
Legionella
are also
related to the presence of other microorganisms, favored by the presence
of protozoans such as:
Hartmnella vermiformes, Tetrahymena pyriformes
,
and amoebas (
Acanthamoeba castellani, Naegleria spp
.) which can endure
the multiplication of the
Legionella ssp
. The bacterium needs nutrients
that are obtained through other microorganisms appropriating their
macromolecules to perform its multiplication. (FERREIRA 2002) (JOSEPH
Et al
2011).
The bacteria of the genus
Legionella
are also found in environments of
artificial aquatic systems, mainly in systems of air conditioning where there is
great facilitation for thedispersionof aerosols.The inhalationof these aerosols is
the vehicle by which the contagion occurs in humans causing the Legionnaires’
disease. (JOSEPH 2011)(BARTRAN
Et al
2007) (Ferreira 2002).
Ecology of
Legionella
A good knowledge on the factors that influence the development of
Legionella
while in its natural environment is of major importance for the
control of the bacterium in artificial environments that represent risks of
transmission of the Legionnaires’ Disease.
