Abstract:
Objectives: Bloodstream fungal infections have increased worldwide during the last two
decades and are considered a serious public health problem. A prospective, observational
study was conducted at a Portuguese University hospital, aiming to evaluate the susceptibility
pattern of isolates from patients with bloodstream fungal infection and to determine the degree
of similitude between distinct isolates of the same patient.
Methods: Yeasts isolated from blood cultures (89) and from other body sites (40) of patients
with fungaemia admitted at a university hospital of Porto were collected and identified with
VITEK 2. Minimal Inhibitory Concentrations (MIC) to fluconazole, posaconazole voriconazole,
amphotericin B, Caspofungin and Anidulafungin were determined according to the protocol
M27-A3 from the Clinical Laboratory for Standards Institute (CLSI). The strains were classified
as S, R, susceptible-dose dependent (S-DD) or non susceptible accordingly the CLSI protocol.
Sixty strains (C. albicans, C. glabrata and C. parapsilosis) isolated from blood cultures (40) and
other biological products (20), from 16 patients were studied regarding the presence of
different restriction patterns after restriction endonuclease analysis (REA) with HinfI enzyme.
Restriction patterns were analyzed using the UVIDOC 12.6 software and compared among the
distinct groups of strains.
Results: From a total of 89 strains isolated from blood cultures during the first fungaemia
episode 43% corresponded to C. albicans, 26% to C. parapsilosis, 13% to C. glabrata and 7%
to C. tropicalis. C. albicans (28%), C. parapsilosis (24%), C. glabrata (18%) and C. krusei
(17%) were the most frequent yeasts isolated from other body sites. Regarding the
susceptibility profile, 8% of C. albicans, 17% of C. parapsilosis, C. tropicalis and 58% of C.
glabrata isolates were resistant to fluconazole. Resistance to equinochandins was detected in
8% of C. glabrata and 22% of C. parapsilosis. Regarding molecular typing, the method did not
provide satisfactory results for C.parapsilosis since the same pattern was obtained when
comparing among different patients. For the other tested Candida species the results obtained
among the different set of isolates for each patient were very heterogeneous. From one patient
yielding C. albicans (n=2) and C. parapsilosis n=(9) strains, isolated both from blood cultures
and other biological products, the differences both in the restriction pattern and susceptibility
profile were only found at a interspecies level. Conversely, the C. albicans strains isolated only
from the blood cultures of 2 patients (3 strains of each one), were all different within each
patient; in one patient the susceptibility profiles were similar but in the other major differences
were registered.
Conclusion: High resistance to azoles and equinochandins was observed. Differences in
susceptibility pattern do not necessarily imply differences in restriction patterns, i.e. different
strains. REA is a rapid and simple technique to be used for strains typing. This technique could
be of value in the follow up of patients under antifungal prophylaxis protocols to clarify strains
relatedness in the case of emergence of fungal infection.
Acknowledgments: S Costa de Oliveira and A P Silva are supported by the grants
SFRH/BD/27662/2006 and SFRH/BD/29540/2006, respectively, from Portuguese Science and
Technology Foundation (FCT).
2009
abstract No:
P226
Full conference title:
4th Trends in Medical Mycology
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- TIMM 4th (2012)