60
Theclinicalpresentationof the infectionvaries frombeingasymptomatic
to havingmild, moderate or severe symptoms, with pulmonary involvement
requiring hospitalization, inclusive in the intensive care unit for respiratory
insufficiency. The radiological alterations show evidence of varied lung
infiltrates in quantity and appearance that can not be distinguished from
other bacterial pulmonary infections, a fact that hinders the suspicion of
Legionella
. In this case, some clinical alterations may suggest the presence
of
Legionella
: non-productive cough, presence of diarrhea, reduced serum
sodium levels, and fever with absence of increased heart rate. The search
for these evidences can help with the suspicion, but they are rare to occur.
Legionella
’s difficulty of growth in conventional cultures or even its
visualization in the bacterioscopy makes the diagnosis difficult and it is
consequently responsible for the sub-notification. For that reason, we
encourage the use of the laboratorial arsenal to have a diagnosis in cases of
community-acquired pneumonias and in hospital-acquired pneumonias,
which is also responsible for nosocomial infections. Sputum or tracheal
secretion samples can be sent to culture. However, the adequate medium
requires theproper aminoacids, iron ions andbufferedcharcoal yeast extract
to the proliferation of
Legionella
. The secretion must be introduced in a
culture medium that is adequate to
Legionella
, known as BCYE (Buffered
charcoal yeast extract) culture medium.
The culture can demonstrate the bacterial growth in a few days. This
often depends on the severity of the pneumonia. In the mild forms of the
disease, the culture positivity occurs in only 15 to 25%, while in the severe
pneumonias with respiratory insufficiency the sensitivity of the culture
exceeds 90%. We point out that the previous use of antimicrobial products
interferes in the test by reducing the bacterial growth chances. To finish, the
