88
after the onset of the disease and only 10% of 68 patients with confirmed
Legionellosisby culture and increase by four times in the antibodies titer had
acute phase titers≥ 256.
6.1.6-6.1.4SerologicalDiagnosisbyEnzymeLinkedImmunosorbent
Assay (ELISA)
Currently, ELISA is themethod that is most commonly used for antibody
detection even if the reported sensitivities vary from 41% to 94%.
In most of the cases, an increase of four times in the titer of antibodies
is detected within 3-4 weeks after the beginning of the symptoms. So, the
serological test for the search of infection caused by
Legionella pneumophila
is a valuable epidemiological tool, but it has little impact on the diagnosis of
Legionellosis in the initial phase of the illness, thus requiring further tests.
6.1.5 Detection of antigens in urine
The urinary antigenof
Legionella pneumophila
canbe detected in 1-3 days
after the onset of the disease and persists for days or even weeks. The available
tests provide results within 30 min and have sensitivity varying between60%
and 100%, and high specificity (> 99%) in patients with Legionellosis due to
the of
Legionella pneumophila
serogroup 1. However, a major disadvantage
with these tests is the inability to detect
Legionella pneumophila
that do not
belong to the serogroup 1.
Following are some important considerations concerning the search of
antigens of
Legionella pneumophila
in urine:1)to provide the early diagnosis
and the initiation of the proper antimicrobial therapy; 2)the recognition of
