Abstract
Fungal infections caused by Candida
species are the fourth leading cause of nosocomial
bloodstream infections in the United States (CDC, 2008).
Although Candida albicans is the most commonly
isolated species, there has been an increase in the number of
non-albicans species isolated. Bloodstream infections caused
by Candida glabrata are of particular concern
because of high mortality rates and growing resistance to
fluconazole, the most commonly prescribed medication for
Candida infections. Inappropriate treatment, such as
treating a resistant organism with fluconazole, or delay of
appropriate treatment of Candida blood stream
infections has been associated with increased costs and increased
mortality (Ferguson, nd). Due to the increasing resistance to
fluconazole shown by C. glabrata and the time
required for species to be indentified in standard blood cultures,
blood stream infections caused by this species of
Candida are especially at risk for inappropriate or
delayed treatment. A unique characteristic of C.
glabrata is that it does not form pseudohyphae. The primary
objective of this research was to analyze the data gathered at the
initial identification of a blood culture positive for yeast and
compare it to the final culture report to assess the predictive
value of the presence or absence of pseudohyphae in
identifying Candida species, in
particular C. glabrata. Secondary objectives
included identifying factors that may influence the primary
objective. Data was collected for a year at Emory Healthcare
facilities. 348 yeast cultures from 145 patients were
assessed. Results: Initial analysis of the data
indicated that pseudohyphae were not noted for any culture positive
for C. glabrata, a 100% negative predictive
value. The risk for C. glabrata in a yeast
culture without pseudohyphae that grows in an anaerobic bottle,
controlling for hours to positive and facility, was determined to
be more than 3 times that of other Candida
species (RR=3.00, CI 2.0, 4.6, p < .0001). Alternatively,
the risk for C. Glabrata in a yeast culture
without pseudohyphae that takes greater than 36 hours to become
positive, controlling for aerobic status and facility, is many
times that of other Candida species (RR =11.40,
CI 1.6, 83.0, p = .016).
Table of Contents
Table of Contents
Introduction..........................................................................................................
1
Problem
Statement...................................................................................................
3
Objectives..............................................................................................................
5
Figure 1: Candida
glabrata………………...…………………………………………...................................….5
Figure 2: Candida with
Pseudohyphae.………………………….…………....................…..........…………..5
Methodology..........................................................................................................
6
Data
Collection..........................................................................................................7
Data
Analysis……………………...……………………………...............................................................8
Results………………………………………………………………………………………….....................................….9
Figure 3: Hours to Positive
Graph…………………………………….………….......................…..........……11
Table 1: Species' Culture and Characteristic
Frequencies………............……………………...........…11
Table 2: Facility Specific Species
Frequencies……………………..................……………….........…….12
Discussion.............................................................................................................13
References…………………………………………………………………..………..................................…………..17
Appendix A: Microbiology
Worksheet………………………………………...............................………....21
Appendix B: 2 x2 Table of
Pseudohyphae
presence………………………......................………….……22
Appendix C: SAS
Output…………………………………………………………………….................................…23
About this Master's Thesis
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