culture in 13 patients in specimens taken from
the respiratory tract on the basis of typical mor-
phologic traits. Ten specimens came from tra-
cheal aspirates and three from BALF. Yeast-
like fungi, predominantly Candida albicans,
were other most frequently isolated species
from other respiratory tract samples. Table 1
presents the species distribution.
Serum samples of the patients in whom fungi
were isolated from the respiratory tract were
tested for the galactomannan antigen. Out of the
200 samples, the antigen was detected in four
taken from patients after liver and kidney trans-
plantation, i.e., being likely immunocompro-
mised. In one of those patients, a culture for
A. fumigatus from BALF yielded a positive
result. In the remaining three, culture confirma-
tion of the presence ofA. fumigatusfailed. The
antigen was not detected in the other 12 patients
who had positive cultures.
4 Discussion
It is difficult to determine the prevalence of inva-
sive pulmonary aspergillosis. Immunoassay
diagnostics, histological and mycological testing,
as well as radiological imaging remain imperfect.
The use of just one diagnostic method is usually
insufficient to confirm the diagnosis. The preva-
lence of invasive pulmonary aspergillosis may
thus be underestimated. Risk groups for invasive
aspergillosis should be better defined and new
diagnostic methods which could accelerate the
diagnosis should be implemented (Backx
et al. 2014 ; Desoubeaux et al. 2014 ). The current
methods are imperfect and the confirmation of
infection by microbiological tests delays the
diagnosis, which often leads to fulminant infec-
tion at the time of successful diagnosis. Further,
microbiological tests all too often fail to confirm
the diagnosisin vivo, and the cause of infection is
discovered posthumously (Maertens et al. 2007 )
(Table2).
Perfect diagnostic markers for invasive fungal
infections are still searched for. Such markers
should be suitable for early disease stages, should
differentiate colonisation from infection, be etio-
logically specific, and not cross-react with
human or other microbial antigens. Further, a
test detecting a given marker should be easy to
perform, standardized, and validated (Yeo and
Wong 2002 ).
In the present study, A. fumigatus was
cultured once in 13 out of the 200 patients at
high risk of invasive fungal infection; ten cases
were cultured from tracheal aspirates and three
from BALF. Only one of the patients with
A. fumigatuscultured from BALF, was classified
as proven invasive aspergillosis according to the
clinical and microbiological criteria developed
by the EORTC/MSG guidelines (de Pauw
et al. 2008 ). The patient manifested clinical
symptoms of a respiratory tract infection and
radiological images showed lesions pointing to
active respiratory infection. In this patient, asper-
gillosis was conclusively confirmed by detecting
the galactomannan antigen in a serum sample.
The remaining 12 patients in whomA. fumigatus
was positively cultured could not be classified to
any of the three EORTC/MSG classes. These
patients did not have any clinical symptoms of
invasive aspergillosis and no galactomannan
antigen was detected in the serum. The failed
detection of the antigen in the presence of posi-
tive culture results could have to do with the
implemented antifungal treatment.
Galactomannan was detected in three other
patients in whomAspergillus spp. culture yieldedTable 1 Prevalence of fungi isolated from respiratory
tract
Species Strains (n) %
C. albicans 111 55.5
C. glabrata 26 13.0
C. parapsilosis 9 4.5
C. tropicalis 9 4.5
C. krusei 7 3.5
C. kefyr 8 4.0
Other yeasts and yeast-like fungi 13 6.5
Aspergillus fumigatus 13 6.5
Other molds 4 2.0
Total 200 10030 E. Swoboda-Kopec ́et al.