Center for Biofilm Engineering
Abstract:
"Action of Chlorhexidine Digluconate against Yeast and Filamentous
Forms in an Early-Stage Candida albicans Biofilm"
02-049 An in situ method for sensitive detection of differences in
the action of chlorhexidine against subpopulations of cells in Candida
albicans biofilms is described. Detection relies on monitoring the kinetics
of propidium iodide (PI) penetration into the cytoplasm of individual cells
during dosing with chlorhexidine. Accurate estimation of the time for delivery
of the dosing concentration to the substratum was facilitated by using a flow
cell system for which transport to the interfacial region was previously
characterized. A model was developed to quantify rates of PI penetration based
on the shape of the kinetic data curves. Yeast were seeded onto the substratum,
and biofilm formation was monitored microscopically for 3 h. During this period
a portion of the yeast germinated, producing filamentous forms (both hyphae and
pseudohyphae). When the population was subdivided on the basis of cell
morphology, rates of PI penetration into filamentous forms appeared to be
substantially higher than for yeast forms. Based on the model, rates of
penetration were assigned to individual cells. These data indicated that the
difference in rates between the two subpopulations was statistically significant
(unpaired t test, P < 0.0001). A histogram of rates and analysis
of variance indicated that rates were approximately equally distributed among
different filamentous forms and between apical and subapical segments of
filamentous forms.
Suci, P.A. and B.J. Tyler, "Action of Chlorhexidine Digluconate against
Yeast and Filamentous Forms in an Early-Stage Candida albicans Biofilm,"
Antimicrob. Agents Chemother., 46(11):3522-3531(2002).
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