Dr. Henry Blumberg from Emory University School of Medicine presented epidemiological data on
Candida bloodstream infections (CBSIs), and reported on the National Epidemiology of Mycosis Survey (NEMIS) study.
Infections with
Candida species are the fourth leading cause of nosocomial bloodstream
infections in the United States.
However, since the introduction of fluconazole, there has been a shift
in the frequency of CBSIs from those caused by
C. albicans species to those caused by non-
albicans species. Recent
population-based surveillance studies of candidemia have reported an incidence
of 52% for
C. albicans infections,
and 48% for non-
albicans infections.
1
Dr. Blumberg pointed out that this shift is being driven mainly by an increase
in
C. glabrata infections.
The NEMIS study was a prospective,
multicenter study in surgical intensive care units (SICUs) and neonatal
intensive care units (NICUs) conducted between 1994 and 1995 in order to
determine rates of and risk factors for CBSIs in these high-risk patients.
2
The study reported that 1% of patients developed a CBSI infection in the SICU,
and 1.2% developed a CBSI in the NICU. In the SICU, 48% of CBSIs were due to
C.
albicans, compared with 63% in the NICU. A multivariate
analysis of the SICU data found that the dominant independent risk factors for
developing a CBSI were prior surgery, acute renal failure, and parenteral
nutrition.
3 Receipt of
an antifungal agent was associated with a decreased risk and lower mortality.
According to Dr. Blumberg, “If you can eliminate all CBSIs, you can
reduce the overall mortality in the SICU by 8%.”
The NEMIS study sets the stage for
large, prospective, multicenter, randomized interventional studies of
antifungal prophylaxis in which some high-risk surgical patients can be
enrolled. Until then, antifungal prophylaxis should be used only for carefully
selected high-risk patients, including a very small proportion of patients in
the SICU.
Dr. Michael Pfaller from the University of Iowa College of
Medicine discussed laboratory aspects of mycologic epidemiology, and reported
on the sentinel antifungal resistance surveillance studies of candidemia
conducted at the University of Iowa over a 10-year period. These studies
reported on trends in species distribution, antifungal susceptibility, and
molecular epidemiology for more than 6,000 CBSIs. The studies found an
increased frequency of
C. glabrata and a decreased frequency of
C.
albicans CBSIs with increasing age, results that complemented the
epidemiology data presented by Dr. Blumberg. The studies also found that BSI
isolates of
C. albicans were more susceptible than
C.
glabrata and
C. krusei to amphotericin B. These non-
albicans species also
demonstrated decreased susceptibility to fluconazole and itraconazole. The data
was also analyzed for cross-resistance to the newer triazole antifungal agents
(voriconazole, posaconazole, and ravuconazole). It was found that fluconazole-
and itraconazole-resistant
Candida isolates were significantly less
susceptible to the newer agents compared to the isolates that were only
fluconazole-resistant. In Dr. Pfaller’s opinion, these sentinel
antifungal resistance surveillance programs provide important information that
may be useful in developing strategies to manage CBSIs by patient group, and
that ongoing surveillance will enhance efforts to limit the extent of
resistance.
References:
1. Kao S, et al. The
epidemiology of candidemia in two United States cities: results of a
population-based active surveillance. Clin Infect Dis 1999;29:1164–70.
2. Rangel-Frausto MS, et al. National
epidemiology of mycoses survey (NEMIS): Variations in rates of blood stream
infections due to Candida species in seven surgical intensive care units and
six neonatal intensive care units. Clin Infect Dis 1999;29:253–8.
3. Blumberg HM, et al. Risk
factors for Candidal blood stream infections in surgical intensive care unit
patients: The NEMIS prospective multicenter study. Clin Infect Dis
2001;33:177–86.
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