Lisa J. Douglas

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Pathogenic fungi in the genus Candida can cause both superficial and serious systemic disease, and are now recognized as major agents of hospital-acquired infection. Many Candida infections involve the formation of biofilms on implanted devices such as indwelling catheters or prosthetic heart valves. Biofilms of Candida albicans formed in vitro on catheter(More)
Matrix material was extracted from biofilms of Candida albicans and Candida tropicalis and analysed chemically. Both preparations contained carbohydrate, protein, hexosamine, phosphorus and uronic acid. However, the major component in C. albicans matrix was glucose (32%), whereas in C. tropicalis matrix it was hexosamine (27%). Biofilms of C. albicans were(More)
A model system for studying Candida biofilms growing on the surface of small discs of catheter material is described. Biofilm formation was determined quantitatively by a colorimetric assay involving reduction of a tetrazolium salt or by [3H]leucine incorporation; both methods gave excellent correlation with biofilm dry weight (r = 0.997 and 0.945,(More)
Prostaglandins are now known to be produced by Candida albicans and may play an important role in fungal colonization. Their synthesis in mammalian cells is decreased by inhibitors of the cyclooxygenase isoenzymes required for prostaglandin formation. In the present study, a catheter disk model system was used to investigate the effects of nonsteroidal(More)
Denture biofilms represent a protective reservoir for oral microbes. The study of the biology of Candida in these biofilms requires a reliable model. A reproducible model of C. albicans denture biofilm was developed and used to determine the susceptibility of two clinically relevant C. albicans isolates against 4 antifungals. C. albicans, growing as a(More)
Biofilms formed by Candida albicans on small discs of catheter material were resistant to the action of five clinically important antifungal agents as determined by [3H]leucine incorporation and tetrazolium reduction assays. Fluconazole showed the greatest activity, and amphotericin B showed the least activity against biofilm cells. These findings were(More)
Extracellular polymeric material (EP), comprising the matrix of Candida albicans biofilms, was isolated and its composition was compared with that of EP obtained from culture supernatants of planktonically grown (suspended) organisms. Both preparations consisted of carbohydrate, protein, phosphorus and hexosamine, but biofilm EP contained significantly less(More)
Growth of Candida albicans biofilms and production of extracellular matrix were monitored by dry weight, colorimetric and radioisotope assays, and by scanning electron microscopy. Under static incubation conditions synthesis of matrix material was minimal, but increased dramatically when developing biofilms were subjected to a liquid flow with the result(More)
Both biofilms and planktonic (suspended) cells of Candida albicans synthesized extracellular prostaglandin(s) during growth at 37 degrees C, but biofilm cells secreted significantly more prostaglandin(s) when production was determined on the basis of cell dry weight. Prostaglandin synthesis by both cell types was sensitive to the cyclooxygenase inhibitors(More)
Two model biofilm systems, involving growth on disks of catheter material or on cylindrical cellulose filters, were used to investigate the structure of Candida albicans biofilms. To assess the importance of dimorphism in biofilm development, biofilms produced by two wild-type strains were compared with those formed by two morphological mutants, incapable(More)