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J Clin Microbiol. 2009
October; 47(10): 3185–3190, PMCID:
PMC2756923
Variation in Susceptibility of
Bloodstream Isolates of
Candida glabrata
to Fluconazole According to Patient
Age and Geographic Location in the
United States in 2001 to 2007.
M. A. Pfaller, S. A. Messer, R. J.
Hollis, L. Boyken, S. Tendolkar, J.
Kroeger, D. J. Diekema.
The purpose of this study was to
examine the susceptibilities to
fluconazole of bloodstream infection
(BSI) isolates of
Candida glabrata
and group the isolates by patient
age and geographic location within
the United States from 2001 to 2007.
A previous study reported on similar
data collected from 1992 to 2001.
Treatment of candidemia over the
past 20 years has been enhanced by
the introduction of fluconazole in
1990, but its widespread usage, has
caused considerable concern about
the development of fluconazole
resistance in candida species.
Candida glabrata has been shown to
be the most susceptible to
developing resistance to
fluconazole. In the United States,
the proportion of cases of blood
sepsis due to
Candida glabrata ranges from
11% to 37% depending on the
geographic region. Because
Candida glabrata
is relatively resistant to
fluconazole, the frequency with
which it causes bloodstream
infections has important
implications for therapy.
In this study, data was analyzed
from six hundred and forty two
bloodstream infection (BSI) isolates
of
Candida glabrata. These isolates
were submitted to the
University Of Iowa College Of
Medicine for identification and
antifungal susceptibility testing,
between 2001 and 2007, from twenty
four sentinel surveillance sites in
the United States. The total of
2,536 BSI isolates of
Candida submitted during that time
frame
represents patients with candidemia
treated at U.S. hospitals, in which
Candida glabrata
was identified as the pathogen in
708 cases.
Candida glabrata was the second most
common candida species isolated.
This study excluded 76 isolates due
to insufficient patient data.
Antifungal testing was done with
fluconazole, voriconazole,
anidulafungin, caspofungin, and
micafungin.
The frequency of
Candida glabrata
as a cause of candidemia in the
United States ranged from 19% in the
northeast to 34% in the west. By
comparison with the results of the
previous study (1992 to 2001), the
proportion of
Candida
BSI isolates that were
C.
glabrata
increased in three of the four
regions and decreased only slightly
in the northeast (from 21% to 19%).
The rates of fluconazole resistance
among the
C.
glabrata
isolates from 2001 to 2007 increased
compared to those from 1992 to 2001
in all regions except for the south,
where the rate was unchanged. The
region with the highest prevalence
of
C.
glabrata
(west; 34%) had the lowest
frequency of resistance (10%).
Overall, 14% of the 2001 to 2007 U.S.
C.
glabrata
isolates were resistant to
fluconazole compared with only 9% in
1992 to 2001. The data also showed
that while the frequency of
C.
glabrata
increased with patient age, the rate
of fluconazole resistance declined.
The variable frequencies of
occurrence and resistance to
fluconazole associated with this
species underscore the need for both
prompt identification and antifungal
susceptibility testing of
bloodstream isolates in order to
optimize antifungal therapy.
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