651
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Bujdáková H, Paulovičová E, Borecká-Melkusová S, Gašperík J, Kucharíková S, Kolecka A, Lell C, Jensen DB, Würzner R, Chorvát D, Pichová I. Antibody response to the 45 kDa Candida albicans antigen in an animal model and potential role of the antigen in adherence. J Med Microbiol 2009; 57:1466-1472. [PMID: 19018015 DOI: 10.1099/jmm.0.2008/001479-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Candida antigen CR3-RP (complement receptor 3-related protein) is supposed to be a 'mimicry' protein because of its ability to bind antibody directed against the alpha subunit of the mammalian CR3 (CD11b/CD18). This study aimed to (i) investigate the specific humoral isotypic response to immunization with CR3-RP in vivo in a rabbit animal model, and (ii) determine the role of CR3-RP in the adherence of Candida albicans in vitro using the model systems of buccal epithelial cells (BECs) and biofilm formation. The synthetic C. albicans peptide DINGGGATLPQ corresponding to 11 amino-acids of the CR3-RP sequence DINGGGATLPQALXQITGVIT, determined by N-terminal sequencing, was used for immunization of rabbits to obtain polyclonal anti-CR3-PR serum and for subsequent characterization of the humoral isotypic response of rabbits. A significant increase of IgG, IgA and IgM anti-CR3-RP specific antibodies was observed after the third (P<0.01) and the fourth (P<0.001) immunization doses. The elevation of IgA levels suggested peptide immunomodulation of the IgA1 subclass, presumably in coincidence with Candida epithelial adherence. Blocking CR3-RP with polyclonal anti-CR3-RP serum reduced the ability of Candida to adhere to BECs, in comparison with the control, by up to 35 % (P<0.001), and reduced biofilm formation by 28 % (P<0.001), including changes in biofilm thickness and integrity detected by confocal laser scanning microscopy. These properties of CR3-RP suggest that it has potential for future vaccine development.
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Affiliation(s)
- Helena Bujdáková
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Ema Paulovičová
- Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Silvia Borecká-Melkusová
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Juraj Gašperík
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Soňa Kucharíková
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Anna Kolecka
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Claudia Lell
- Department of Hygiene, Microbiology and Social Medicine, Innsbruck Medical University, Austria
| | - Dorthe B Jensen
- Department of Hygiene, Microbiology and Social Medicine, Innsbruck Medical University, Austria
| | - Reinhard Würzner
- Department of Hygiene, Microbiology and Social Medicine, Innsbruck Medical University, Austria
| | - Dušan Chorvát
- Department of Biophotonics, International Laser Centre, Bratislava, Slovakia
| | - Iva Pichová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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652
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Sudheesh MS, Jain V, Shilakari G, Kohli DV. Development and characterization of lectin-functionalized vesicular constructs bearing amphotericin B for bio-film targeting. J Drug Target 2009; 17:148-58. [DOI: 10.1080/10611860802546629] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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653
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Krom BP, Cohen JB, McElhaney-Feser G, Busscher HJ, van der Mei HC, Cihlar RL. Conditions for optimal Candida biofilm development in microtiter plates. Methods Mol Biol 2009; 499:55-62. [PMID: 19152039 DOI: 10.1007/978-1-60327-151-6_7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Development of Candida spp. biofilms on medical devices such as catheters and voice prosthesis has been recognized as an increasing clinical problem. Simple device removal is often impossible, while in addition, resulting candidal infections are difficult to resolve due to their increased resistance to many antifungal agents. Susceptibility studies of clinical isolates are generally performed according to the CLSI standard, which measures planktonic cell susceptibility, but similar standards have not been designed or applied to testing of cells growing within a biofilm. As consistent biofilms from many strains are more difficult to simultaneously obtain and analyze than are independent planktonic cultures, any standard assay must address these concerns. In the present chapter, optimized conditions that promote biofilm formation within individual wells of microtiter plates are described. In addition, the method has proven useful in preparing C. albicans biofilms for investigation by a variety of microscopic and molecular techniques.
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Affiliation(s)
- Bastiaan P Krom
- Department of Biomedical Engineering, University Medical Center Groningen and the University of Groningen, Groningen, The Netherlands
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654
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Pierce CG, Thomas DP, López-Ribot JL. Effect of tunicamycin on Candida albicans biofilm formation and maintenance. J Antimicrob Chemother 2008; 63:473-9. [PMID: 19098294 DOI: 10.1093/jac/dkn515] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Candida albicans is a common opportunistic pathogen of the human body and is the frequent causative agent of candidiasis. Typically, these infections are associated with the formation of biofilms on both host tissues and implanted biomaterials. As a result of the intrinsic resistance of C. albicans biofilms to most antifungal agents, new strategies are needed to combat these infections. METHODS Here we have used a 96-well microtitre plate model of C. albicans biofilm formation to study the inhibitory effect of tunicamycin, a nucleoside antibiotic that inhibits N-linked glycosylation affecting cell wall and secreted proteins, on C. albicans biofilm formation. A proteomic approach was used to study the effect of tunicamycin on levels of glycosylation of key secreted mannoproteins in the biofilm matrix. RESULTS Our results revealed that physiological concentrations of tunicamycin displayed significant inhibitory effects on biofilm development and maintenance, while not affecting overall cell growth or morphology. However, tunicamycin exerted a minimal effect on fully mature, pre-formed C. albicans biofilms. CONCLUSIONS The effect of tunicamycin on the C. albicans biofilm mode of growth demonstrates the importance of N-linked glycosylation in the developmental stages of biofilm formation. In addition, our results indicate that N-linked glycosylation represents an attractive target for the development of alternative strategies for the prevention of biofilm formation by this important pathogenic fungus.
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Affiliation(s)
- Christopher G Pierce
- Department of Biology and South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, USA
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655
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Borecká-Melkusová S, Bujdáková H. Variation of cell surface hydrophobicity and biofilm formation among genotypes of Candida albicans and Candida dubliniensis under antifungal treatment. Can J Microbiol 2008; 54:718-24. [PMID: 18772934 DOI: 10.1139/w08-060] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Candida infections are frequently associated with formation of biofilms on artificial medical devices. This work studied variation of cell surface hydrophobicity (CSH) and formation of biofilm in relation to Candida albicans and Candida dubliniensis genotypes and an effect of some conventional antifungal agents on both CSH and biofilm. The 50 isolates of C. albicans and C. dubliniensis were classified into genotypes A, B, C, and D, genotype D being exclusively represented by C. dubliniensis. No significant differences between CSH of genotypes A and B and B and C were observed with respect to cultivation temperature 25 or 37 degrees C. Candida dubliniensis showed increased CSH in comparison with other C. albicans genotypes (p < 0.001) regardless of temperature used. Using XTT reduction assay and dry masses, genotypes B and C showed reduced ability to form biofilm in comparison with genotype A (p < 0.05) and C. dubliniensis (p < 0.001). Fluconazole reduced biofilm in C. albicans genotypes A, B, and C (p < 0.05) but not CSH. The opposite effect was observed in C. dubliniensis. Voriconazole effectively reduced both biofilm formation and CSH in all tested genotypes of C. albicans and C. dubliniensis (p < 0.05).
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Affiliation(s)
- Silvia Borecká-Melkusová
- Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Mlynská dolina B-2, 842 15 Bratislava, Slovak Republic
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656
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Ruan SY, Chien JY, Hsueh PR. Persistent Candida parapsilosis funguria associated with an indwelling urinary tract stent for more than 7 years. J Med Microbiol 2008; 57:1585-1587. [DOI: 10.1099/jmm.0.2008/003202-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Candiduria is an increasingly common condition, and the lack of effective antifungal treatment in many cases has raised great concern. We report a case of persistent Candida parapsilosis funguria associated with urinary tract instrumentation. Molecular typing suggested that during a 7 year period the C. parapsilosis isolates were all the same strain. Prolonged antifungal therapy and regular catheter replacement failed to eradicate the funguria, but improved urinary symptoms and pyuria. The antifungal susceptibility pattern did not significantly change during the clinical course despite repeated exposure to fluconazole.
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Affiliation(s)
- Sheng-Yuan Ruan
- Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan, ROC
| | - Jung-Yien Chien
- Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan, ROC
| | - Po-Ren Hsueh
- Departments of Internal Medicine and Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan, ROC
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657
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Diez-Orejas R, Fernández-Arenas E. Candida albicans–macrophage interactions: genomic and proteomic insights. Future Microbiol 2008; 3:661-81. [DOI: 10.2217/17460913.3.6.661] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Candida albicans infection is a significant cause of morbidity and mortality in immunocompromised patients. In vivo and in vitro models have been developed to study both the fungal and the mammalian immune responses. Phagocytic cells (i.e., macrophages) play a key role in innate immunity against C. albicans by capturing, killing and processing the pathogen for presentation to T cells. The use of microarray technology to study global fungal transcriptional changes after interaction with different host cells has revealed how C. albicans adapts to its environment. Proteomic tools complement molecular approaches and computational methods enable the formulation of relevant biological hypotheses. Therefore, the combination of genomics, proteomics and bioinformatics tools (i.e., network analyses) is a powerful strategy to better understand the biological situation of the fungus inside macrophages; part of the fungal population is killed while a significantly high percentage survives.
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Affiliation(s)
- Rosalía Diez-Orejas
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain
| | - Elena Fernández-Arenas
- Centro de Biología Molecular Severo Ochoa (CBM-SO), Consejo Superior de Investigaciones Científicas (CSIC), Nicolás Cabrera 1, Cantoblanco, 28049 Madrid, Spain
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658
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Review of techniques for diagnosis of catheter-related Candida biofilm infections. CURRENT FUNGAL INFECTION REPORTS 2008. [DOI: 10.1007/s12281-008-0035-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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659
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Evaluation and Treatment of Candida Species in Prosthetic Joint Infections. INFECTIOUS DISEASES IN CLINICAL PRACTICE 2008. [DOI: 10.1097/ipc.0b013e31817cfdb7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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660
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Pemán J, Cantón E, Valentín A. [Activity of anidulafungin against Candida biofilms]. Rev Iberoam Micol 2008; 25:124-8. [PMID: 18473507 DOI: 10.1016/s1130-1406(08)70030-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Currently, no standardized method to study the in vitro activity of antifungal agents on biofilms is available, thus, the comparison among different authors is difficult. The studies discussed in this review use the XTT reduction to measure the activity of antifungals on biofilms of 24 h of maturation. To date, biofilm anidulafungin MICs of 47 isolates of Candida spp. (25 Candida albicans, 16 Candida tropicalis, 5 Candida dubliniensis and 1 Candida parapsilosis) have been published. The geometric mean MIC of anidulafungin on biofilms of Candida spp. is of 1.18 microg/ml. Against isolates of species with great capacity of biofilm formation, the geometric mean MIC is 0.325 (C. albicans), 2 (C. parapsilosis) and 0.5 microg/ml (C. dubliniensis). No echinocandin has activity on C. tropicalis biofilms. In addition, anidulafungin can be used for lock therapy of catheters since it is the echinocandin with the least in vitro paradoxical effect.
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Affiliation(s)
- Javier Pemán
- Servicio de Microbiología, Centro de Investigación, Hospital Universitario La Fe, Valencia, Spain.
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661
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Shi Y, Song W, Feng ZH, Zhao YT, Li F, Tian Y, Zhao YM. Disinfection of maxillofacial silicone elastomer using a novel antimicrobial agent: recombinant human beta-defensin-3. Eur J Clin Microbiol Infect Dis 2008; 28:415-20. [PMID: 18841402 DOI: 10.1007/s10096-008-0634-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Accepted: 09/12/2008] [Indexed: 11/30/2022]
Abstract
Maxillofacial silicone elastomer, when used as a prosthesis, is in contact with wound surfaces and mucosa, and tends to be contaminated with microorganisms from a patient's saliva and blood. The aim of the study was to evaluate the efficacy of human beta-defensin-3 (HBD3) on the reduction of two resistant bacteria species from the surface of maxillofacial silicone elastomer. HBD3 cDNA was amplified from total RNA, which had been extracted from human gingival epithelium by means of reverse-transcription polymerase chain reaction (RT-PCR). Following this, the cDNA fragments were recombined in a prokaryotic expression vector. The constructed expression vectors pET-32a/HBD3 were transformed into Escherichia coli to obtain recombinant protein. After protein purification and refolding, the product was verified in classic antimicrobial experiments against Staphylococcus aureus and Candida albicans. Specimens made of silicone elastomer A-2186, which had been contaminated with S. aureus or C. albicans, were immersed in rHBD3 or 5.25% sodium hypochlorite (a positive control) for 5 min, 10 min, 30 min, or 60 min. The active recombinant HBD3 obtained in the current study eliminated the S. aureus and C. albicans microorganism from the surface of the maxillofacial elastomer after a 30-min immersion. There was no statistically significant difference between the rHBD3 group and the sodium hypochlorite 5.25% group. In conclusion, rHBD3 exhibits antibacterial activity against oral pathogenic strains that adhere to maxillofacial elastomer, and may, thus, contribute to the prevention of infections caused by S. aureus and C. albicans.
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Affiliation(s)
- Y Shi
- Department of Prosthodontics, Fourth Military Medical University, Xi'an, Shaanxi Province, China.
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662
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663
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Complementary adhesin function in C. albicans biofilm formation. Curr Biol 2008; 18:1017-24. [PMID: 18635358 DOI: 10.1016/j.cub.2008.06.034] [Citation(s) in RCA: 237] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 06/08/2008] [Accepted: 06/12/2008] [Indexed: 01/09/2023]
Abstract
BACKGROUND Biofilms are surface-associated microbial communities with significant environmental and medical impact. Here, we focus on an adherence mechanism that permits biofilm formation by Candida albicans, the major invasive fungal pathogen of humans. RESULTS The Als surface-protein family has been implicated in biofilm formation, and we show that Als1 and Als3 have critical but redundant roles. Overexpression of several other Als proteins permits biofilm formation in a biofilm-defective als1/als1 als3/als3 strain, thus arguing that the function of Als proteins in this process is governed by their respective expression levels. The surface protein Hwp1 is also required for biofilm formation, and we find that a mixture of biofilm-defective hwp1/hwp1 and als1/als1 als3/als3 strains can form a hybrid biofilm both in vitro and in vivo in a catheter infection model. Complementary function of Hwp1 and Als1 and 3 seems to reflect their interaction because expression of Hwp1 in the heterologous host S. cerevisiae permits adherence to wild-type C. albicans, but not to an als1/als1 als3/als3 strain. CONCLUSIONS The complementary roles of Hwp1 and Als1 and Als3 in biofilm formation are analogous to the roles of sexual agglutinins in mating reactions. This analogy suggests that biofilm-adhesin complementarity may promote formation of monospecies biofilms.
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664
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Monitoring ALS1 and ALS3 Gene Expression During In Vitro Candida albicans Biofilm Formation Under Continuous Flow Conditions. Mycopathologia 2008; 167:9-17. [DOI: 10.1007/s11046-008-9148-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Accepted: 07/15/2008] [Indexed: 10/21/2022]
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665
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In vitro evaluation of putative virulence attributes of oral isolates of Candida spp. obtained from elderly healthy individuals. Mycopathologia 2008; 166:209-17. [PMID: 18597183 DOI: 10.1007/s11046-008-9139-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 06/17/2008] [Indexed: 10/21/2022]
Abstract
Identification of Candida isolates obtained from oral cavity of elderly healthy individuals revealed the predominance of non-albicans Candida species (88.9%) compared to Candida albicans (11%). CHROMagar Candida differential medium and PCR revealed the presence of Candida tropicalis (33.3%), Candida glabrata (27.8%), and Candida krusei (16.7%). We investigated the presence of virulence attributes in a total of 18 isolates, including acid protease and phospholipase production, hemolytic activity, and biofilm production. Extracellular protease was found in five isolates (27.8%) whereas extracellular phospholipase was found in three isolates (17%). All isolates showed hemolytic activity. About 56% of the isolates were weakly positive for biofilm formation (score +) whereas a minority (5.6%) of them showed strong biofilm formation (score 4+). Susceptibility in vitro of the isolates to fluconazole was carried out by microdilution method. Fluconazole showed a strong inhibition against most buccal isolates. The resistant isolates were 2 C. tropicalis, 2 C. glabrata, and 1 C. krusei.
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666
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Ramage G, Wickes BL, López-Ribot JL. A seed and feed model for the formation of Candida albicans biofilms under flow conditions using an improved modified Robbins device. Rev Iberoam Micol 2008; 25:37-40. [PMID: 18338926 DOI: 10.1016/s1130-1406(08)70009-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
A variety of manifestations of Candida albicans infections are associated with the formation of biofilms on the surface of biomaterials. In order to maintain their niche these adherent populations need to withstand the continuous bathing action of physiological fluids (saliva, blood), which also provide water and nutrients to the fungal cells. Thus, it was the aim of this study to examine and further characterize the development of C. albicans biofilms under shear forces and a flow of replenishing nutrients, emulating the conditions that fungal cells would normally encounter within the host. An improved modified Robbins device (MRD) was designed to hold six poly methyl methacrylate (PMMA) plugs of 25 mm in diameter. A "seed and feed" model of biofilm formation was then implemented for which the apparatus was initially seeded with a C. albicans cell suspension to allow initial adhesion of fungal cells to the biomaterial. Following this initial step, sterile medium was then pumped through the MRD at a constant flow rate. Scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM) demonstrated a high degree of heterogeneity associated with the structure of biofilms formed under flowing conditions using the MRD. In addition, these biofilms displayed a complex three dimensional architecture and increased production of exopolymeric material.
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Affiliation(s)
- Gordon Ramage
- Department of Biology and South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, Texas 78249, USA
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667
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Abstract
Candida biofilm formation is common during infection and environmental growth. We tested the impacts of three biocides (ethanol [EtOH], H(2)O(2), and sodium dodecyl sulfate) on Candida albicans, C. parapsilosis, and C. glabrata biofilms. Higher concentrations of the biocides were required for efficacy against biofilms than for efficacy against planktonic controls. A combination study with two biocides (EtOH and H(2)O(2)) and fluconazole demonstrated that the combination had enhanced efficacy.
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668
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Fritz JM, Brielmaier BD, Dubberke ER. Micafungin for the prophylaxis and treatment of Candida infections. Expert Rev Anti Infect Ther 2008; 6:153-62. [PMID: 18380597 DOI: 10.1586/14787210.6.2.153] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Invasive fungal infection is a significant cause of morbidity and mortality worldwide. The incidence of these infections is steadily increasing. In addition, strains resistant to many commonly used antifungal agents are becoming more prevalent. Many new antifungals have become commercially available in recent years, which have vastly improved the ability to treat these infections effectively. Micafungin is one of three commercially available echinocandins available for use in the USA. This class of agents possess a unique mechanism of action that helps to reduce toxicity while maintaining potent antifungal activity. Micafungin is currently approved for the treatment of esophageal candidiasis in adults and is the only in its class approved for the prophylaxis of Candida infection in patients who have undergone hematopoietic stem cell transplantation. It was also recently approved in the USA for the treatment of candidemia and other forms of invasive candiaisis (acute disseminated candiaisis, Candida peritonitis and abscess). In general, micafungin is well tolerated and has favorable safety and drug-interaction profiles.
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Affiliation(s)
- Joseph M Fritz
- Washington University School of Medicine, Division of Infectious Diseases, Department of Internal Medicine, 660 South Euclid Avenue, Campus Box 8051, St Louis, MO 63110, USA.
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669
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Abstract
PURPOSE OF REVIEW Owing to the high mortality, risk of neurodevelopmental impairment and end-organ involvement with fungal infections in the neonate, prevention of invasive Candida infections in extremely preterm infants should be a priority for each neonatal ICU. RECENT FINDINGS Even with prompt or empiric treatment, mortality and neurodevelopmental impairment is high (57%) in infants <1000 g. Multiple studies have been performed with fluconazole prophylaxis, including a recent multicenter randomized controlled trial. All of the studies have demonstrated efficacy and safety with no increase or emergence of fungal resistance. Analysis of these studies demonstrates that fluconazole prophylaxis decreased the incidence of invasive Candida infections in high-risk infants <1000 g by 91% (P = 0.0004) and all infants <1500 g by 85% (P < 0.0001). The mortality rate from all causes was 25% lower (P = 0.029). Furthermore, studies have demonstrated that all Candida-related mortality can be eliminated in an entire neonatal ICU by targeting fluconazole prophylaxis in infants <1000 g. SUMMARY Targeting fluconazole prophylaxis to infants who are either <1000 g or < or =27 weeks is highly effective, safe and inexpensive, and can eliminate these infections as a cause of neurodevelopmental impairment and mortality.
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670
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Abstract
Biofilms are communal structures of microorganisms encased in an exopolymeric coat that form on both natural and abiotic surfaces and have been associated with a variety of persistent infections that respond poorly to conventional antibiotic chemotherapy. Biofilm infections of certain indwelling medical devices by common pathogens such as staphylococci are not only associated with increased morbidity and mortality but are also significant contributors to the emergence and dissemination of antibiotic resistance traits in the nosocomial setting. Current treatment paradigms for biofilm-associated infections of semipermanent indwelling devices typically involve surgical replacement of the device combined with long-term antibiotic therapy and incur high health care costs. This review summarizes the existing data relating to the nature, prevalence, and treatment of biofilm-associated infections and highlights experimental approaches and therapies that are being pursued toward more effective treatments.
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Affiliation(s)
- A Simon Lynch
- Cumbre Pharmaceuticals Inc., Dallas, Texas 75235-2304, USA.
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671
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Sennhenn-Kirchner S, Schwarz P, Schliephake H, Konietschke F, Brunner E, Borg-von Zepelin M. Decontamination efficacy of erbium:yttrium-aluminium-garnet and diode laser light on oral Candida albicans isolates of a 5-day in vitro biofilm model. Lasers Med Sci 2008; 24:313-20. [PMID: 18458992 PMCID: PMC5486503 DOI: 10.1007/s10103-008-0561-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 03/19/2008] [Indexed: 11/04/2022]
Abstract
The different forms of superficial and systemic candidiasis are often associated with biofilm formation on surfaces of host tissues or medical devices. The biofilm formation of Candida spp., in general, necessitates significantly increased amounts of antifungal agents for therapy. Often the therapeutic effect is doubtful. A 5-day biofilm model with oral Candida isolates was established according to Chandra et al. [39](J Dent Res 80:903–908, 2001) on glass and titanium surfaces and was modified by Sennhenn-Kirchner et al. [40](Z Zahnärztl Implantol 3:45–51, 2007) to investigate different aspects unanswered in the field of dentistry. In this model, the efficacy of erbium:yttrium–aluminium–garnet (Er:YAG) light (2940 nm, 100 mJ, 10 Hz, 300 μs pulsed mode applied for 80 s) and diode laser light (810 nm, 1 W, continuous wave mode applied for 20 s with four repetitions after 30 s pauses each) was evaluated and compared to untreated controls. The photometric evaluation of the samples was completed by observations on morphological changes of yeast cells grown in the biofilm. Compared to the untreated controls Candida cells grown in mature in vitro biofilms were significantly reduced by both wavelengths investigated. Comparison between the different methods of laser treatment additionally revealed a significantly greater effect of the Er:YAG over the diode laser. Scanning electron microscopy findings proved that the diode laser light was effective in direct contact mode. In contrast, in the areas without direct contact, the fungal cells were left almost unchanged. The Er:YAG laser damaged the fungal cells to a great extent wherever it was applied.
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Affiliation(s)
- Sabine Sennhenn-Kirchner
- Department of Oral and Maxillofacial Surgery, Georg-August University of Goettingen, Göttingen, Germany.
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672
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The potential of lipid- and polymer-based drug delivery carriers for eradicating biofilm consortia on device-related nosocomial infections. J Control Release 2008; 128:2-22. [DOI: 10.1016/j.jconrel.2008.01.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 01/08/2008] [Indexed: 11/23/2022]
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673
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Ader F, Faure K, Guery B, Nseir S. Interaction de Pseudomonas aeruginosa avec Candida albicans dans les voies respiratoires: de la physiopathologie à une perspective thérapeutique. ACTA ACUST UNITED AC 2008; 56:164-9. [PMID: 17905537 DOI: 10.1016/j.patbio.2007.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2007] [Accepted: 06/15/2007] [Indexed: 11/26/2022]
Abstract
Several studies evidenced a pathogenic interaction between P. aeruginosa and C. albicans. P. aeruginosa is one of the most frequent microorganisms responsible for ventilator-associated pneumonia (VAP) and C. albicans usually colonize tracheo-bronchial tract of patients undergoing mechanical ventilation in the intensive care unit. In vitro, P. aeruginosa exploits filamentous fungi resulting in fungal killing and limitation of C. albicans growth in the host. Biofilm also play an important role as a persistent source of infectious material for recurrent episodes of VAP. Indeed, Candida spp and P. aeruginosa are the most common pathogens retrieved from endotracheal tube biofilm and tracheal secretions in patients with VAP. Finally, it has been demonstrated that previous tracheo-bronchial C. albicans colonization enhanced the incidence of P. aeruginosa pneumonia in a murine model. A recent study performed in patients requiring intubation and mechanical ventilation identified Candida spp tracheo-bronchial colonization as a risk factor for P. aeruginosa VAP. In addition, a retrospective study suggested that antifungal treatment might reduce P. aeruginosa VAP or tracheo-bronchial colonization in intubated patients with Candida spp tracheo-bronchial colonization. These interactions have major environmental and medical consequences. Experimental studies providing a better understanding of the mechanisms of interaction and clinical studies evaluating the necessity of a antifungal treatment might improve the management of these opportunistic infections.
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Affiliation(s)
- F Ader
- Laboratoire de recherche en pathologie infectieuse, EA 2689, faculté de médecine de Lille, place de Verdun, Lille cedex, France
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Valentín A, Cantón E, Pemán J, Quindós G. [In vitro activity of amphotericin B and anidulafungin against Candida spp. biofilms]. Rev Iberoam Micol 2008; 24:272-7. [PMID: 18095759 DOI: 10.1016/s1130-1406(07)70055-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Invasive infections caused by Candida spp. are increasing worldwide and are becoming an important cause of morbidity and mortality in immunocompromised patients. A large number of manifestations of candidiasis are associated with the formation of biofilms on inert or biological surfaces. Candida spp. biofilms are recalcitrant to treatment with conventional antifungal therapies. The aim of this study was dual 1) to determine the prevalence of biofilm producers among clinical isolates from catheter (16 C. albicans ) and blood culture (2 C. albicans and 30 C. tropicalis), and 2) to determine the activity of amphotericin B and anidulafungin against C. albicans and C. tropicalis biofilms of 24 and 48 hours of maturation. Biofilms were developed using a 96-well microtitre plate model and production and activity of antifungal agents against biofilms were determined by the tetrazolium (XTT) reduction assay. Of catheter and blood isolates, 62.5 and 56.25%, respectively, produced biofilms. By species, 68.42% of C. albicans and 53.33% of C. tropicalis were biofilm producers. C. albicans biofilms showed more resistance to amphotericin B and anidulafungin than their planktonic counterparts. Complete killing of biofilms was never achieved, even at the highest concentrations of the drugs tested. Anidulafungin displayed more activity than amphotericin B against C. albicans biofilms of 24 hours of maturation (GM MIC 0.354 vs. 0.686 microg/ml), but against C. tropicalis biofilms amphotericin B was more active (GM MIC 11.285 vs. 0.476 microg/ml). In contrast, against biofilms with 48 hours maturation, amphotericin B was more active against both species.
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Affiliation(s)
- Amparo Valentín
- Unidad de Microbiología Experimental, Centro Investigación, Hospital Universitario La Fe, Valencia, Spain
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676
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Absence of amphotericin B-tolerant persister cells in biofilms of some Candida species. Antimicrob Agents Chemother 2008; 52:1884-7. [PMID: 18285487 DOI: 10.1128/aac.01473-07] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biofilms and planktonic cells of five Candida species were surveyed for the presence of persister (drug-tolerant) cell populations after exposure to amphotericin B. None of the planktonic cultures (exponential or stationary phase) contained persister cells. However, persisters were found in biofilms of one of two strains of Candida albicans tested and in biofilms of Candida krusei and Candida parapsilosis, but not in biofilms of Candida glabrata or Candida tropicalis. These results suggest that persister cells cannot solely account for drug resistance in Candida biofilms.
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677
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Donlan RM. Biofilms on Central Venous Catheters: Is Eradication Possible? Curr Top Microbiol Immunol 2008; 322:133-61. [DOI: 10.1007/978-3-540-75418-3_7] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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678
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Durán EL, Mujica MT, Jewtuchowicz VM, Finquelievich JL, Pinoni MV, Iovannitti CA. Estudio de la variabilidad genética entre aislamientos clínicos de Candida albicans formadores de biopelículas. Rev Iberoam Micol 2007; 24:268-71. [DOI: 10.1016/s1130-1406(07)70054-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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679
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Yeater KM, Chandra J, Cheng G, Mukherjee PK, Zhao X, Rodriguez-Zas SL, Kwast KE, Ghannoum MA, Hoyer LL. Temporal analysis of Candida albicans gene expression during biofilm development. MICROBIOLOGY-SGM 2007; 153:2373-2385. [PMID: 17660402 DOI: 10.1099/mic.0.2007/006163-0] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Microarrays were used to identify changes in gene expression associated with Candida albicans biofilm development. Two biofilm substrates (denture and catheter), and two C. albicans strains for each substrate, were tested to remove model- and strain-dependent variability from the overall dataset. Three biofilm developmental phases were examined: early (6 h), intermediate (12 h), and mature (48 h). Planktonic specimens were collected at the same time points. Data analysis focused primarily on gene expression changes over the time-course of biofilm development. Glycolytic and non-glycolytic carbohydrate assimilation, amino acid metabolism, and intracellular transport mechanisms were important during the early phase of biofilm formation. These early events increase intracellular pools of pyruvate, pentoses and amino acids, which prepare the biofilm for the large biomass increase that begins around 12 h of development. This developmental stage demands energy and utilizes specific transporters for amino acids, sugars, ions, oligopeptides and lactate/pyruvate. At mature phase (48 h), few genes were differentially expressed compared with the 12 h time point, suggesting a relative lack of initiation of new metabolic activity. Data analysis to assess biofilm model-specific gene expression showed more dynamic changes in the denture model than in the catheter model. Data analysis to identify gene expression changes that are associated with each strain/substrate combination identified the same types of genes that were identified in the analysis of the entire dataset. Collectively, these data suggest that genes belonging to different, but interconnected, functional categories regulate the morphology and phenotype of C. albicans biofilm.
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Affiliation(s)
- Kathleen M Yeater
- Department of Pathobiology, University of Illinois, Urbana, IL 61802, USA
| | - Jyotsna Chandra
- Center for Medical Mycology, Department of Dermatology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH 44106, USA
| | - Georgina Cheng
- Department of Pathobiology, University of Illinois, Urbana, IL 61802, USA
| | - Pranab K Mukherjee
- Center for Medical Mycology, Department of Dermatology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xiaomin Zhao
- Department of Pathobiology, University of Illinois, Urbana, IL 61802, USA
| | | | - Kurt E Kwast
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, IL 61801, USA
| | - Mahmoud A Ghannoum
- Center for Medical Mycology, Department of Dermatology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH 44106, USA
| | - Lois L Hoyer
- Department of Pathobiology, University of Illinois, Urbana, IL 61802, USA
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680
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Ramage G, Wickes BL, López-Ribot JL. Inhibition on Candida albicans biofilm formation using divalent cation chelators (EDTA). Mycopathologia 2007; 164:301-6. [PMID: 17909983 DOI: 10.1007/s11046-007-9068-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Accepted: 09/19/2007] [Indexed: 11/29/2022]
Abstract
Candida albicans can readily form biofilms on both inanimate and biological surfaces. In this study we investigated a means of inhibiting biofilm formation using EDTA (Ethylenediaminetetra-acetic acid), a divalent cation chelating agent, which has been shown to affect C. albicans filamentation. Candida albicans biofilms were formed in 96-well microtitre plates. Cells were allowed to adhere for 1, 2, and 4 h at 37 degrees C, washed in PBS, and then treated with different concentrations of EDTA (0, 2.5, 25, and 250 mM). EDTA was also added to the standardized suspension prior to adding to the microtiter plate and to a preformed 24 h biofilm. All plates were then incubated at 37 degrees C for an additional 24 h to allow for biofilm formation. The extent and characteristics of biofilm formation were then microscopically assessed and with a semi-quantitative colorimetric technique based on the use of an XTT-reduction assay. Northern blot analysis of the hyphal wall protein (HWP1) expression was also monitored in planktonic and biofilm cells treated with EDTA. Microscopic analysis and colorimetric readings revealed that filamentation and biofilm formation were inhibited by EDTA in a concentration dependent manner. However, preformed biofilms were minimally affected by EDTA (maximum of 31% reduction at 250 mM). The HWP1 gene expression was reduced in EDTA-treated planktonic and biofilm samples. These results indicate that EDTA inhibits C. albicans biofilm formation are most likely through its inhibitory effect on filamentation and indicates the potential therapeutic effects of EDTA. This compound may serve a non-toxic means of preventing biofilm formation on infections with a C. albicans biofilm etiology.
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Affiliation(s)
- Gordon Ramage
- Section of Infection and Immunity, Glasgow Dental School and Hospital, The University of Glasgow, Glasgow, UK
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681
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Abstract
Pericarditis due to Candida species is a rare clinical entity, associated with thoracic surgery and immunosuppression. We report here the second case of pericarditis due to Candida albicans in a heart transplant patient, which presented as tamponade approximately 3 weeks post transplant, in the absence of evidence of sternal osteomyelitis. The patient was treated with pericardiocentesis and a combination of caspofungin and fluconazole, but the patient ultimately required the explantation of retained epicardial leads and the creation of a pericardial window. This case illustrates that Candida species must be considered in the differential diagnosis in post-transplant pericarditis, and that foreign body removal is, as always, key in helping to resolve such infections. This case also demonstrates the first use of caspofungin with fluconazole to treat Candida pericarditis. We discuss the conflicting data regarding the use of caspofungin, alone or in combination therapy, in treating infections involving biofilms, such as the infected pericardium.
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Affiliation(s)
- Y A Puius
- Department of Medicine, Division of Infectious Diseases, Columbia University Medical Center, New York, New York 10032, USA
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682
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Bauer J, Wendland J. Candida albicans Sfl1 suppresses flocculation and filamentation. EUKARYOTIC CELL 2007; 6:1736-44. [PMID: 17766464 PMCID: PMC2043394 DOI: 10.1128/ec.00236-07] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hyphal morphogenesis in Candida albicans is regulated by multiple pathways which act by either inducing or repressing filamentation. Most notably, Tup1, Nrg1, and Rfg1 are transcriptional repressors, while Efg1, Flo8, Cph1, and Czf1 can induce filamentation. Here, we present the functional analysis of CaSFL1, which encodes the C. albicans homolog of the Saccharomyces cerevisiae SFL1 (suppressor of flocculation) gene. Deletion of CaSFL1 results in flocculation (i.e., the formation of clumps) of yeast cells, which is most pronounced in minimal medium. The flocs contained hyphae already under noninducing conditions, and filamentation could be enhanced with hypha-inducing cues at 37 degrees C. Expression of SFL1 in a heterozygous mutant under the control of the CaMET3 promoter was shown to complement these defects and allowed switching between wild-type and mutant phenotypes. Interestingly, increased expression of SFL1 using a MET3prom-SFL1 construct prior to the induction of filamentation completely blocked germ tube formation. To localize Sfl1 in vivo, we generated a SFL1-GFP fusion. Sfl1-green fluorescent protein was found in the nucleus in both yeast cells and, to a lesser extent, hyphal cells. Using reverse transcription-PCR, we find an increased expression of ALS1, ALS3, HWP1, ECE1, and also FLO8. Our results suggest that Sfl1 functions in the repression of flocculation and filamentation and thus represents a novel negative regulator of C. albicans morphogenesis.
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Affiliation(s)
- Janine Bauer
- Carlsberg Laboratory, Yeast Biology, Gamle Carlsberg Vej 10, DK-2500 Valby, Copenhagen, Denmark
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683
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Breger J, Fuchs BB, Aperis G, Moy TI, Ausubel FM, Mylonakis E. Antifungal chemical compounds identified using a C. elegans pathogenicity assay. PLoS Pathog 2007; 3:e18. [PMID: 17274686 PMCID: PMC1790726 DOI: 10.1371/journal.ppat.0030018] [Citation(s) in RCA: 254] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Accepted: 12/27/2006] [Indexed: 11/18/2022] Open
Abstract
There is an urgent need for the development of new antifungal agents. A facile in vivo model that evaluates libraries of chemical compounds could solve some of the main obstacles in current antifungal discovery. We show that Candida albicans, as well as other Candida species, are ingested by Caenorhabditis elegans and establish a persistent lethal infection in the C. elegans intestinal track. Importantly, key components of Candida pathogenesis in mammals, such as filament formation, are also involved in nematode killing. We devised a Candida-mediated C. elegans assay that allows high-throughput in vivo screening of chemical libraries for antifungal activities, while synchronously screening against toxic compounds. The assay is performed in liquid media using standard 96-well plate technology and allows the study of C. albicans in non-planktonic form. A screen of 1,266 compounds with known pharmaceutical activities identified 15 (approximately 1.2%) that prolonged survival of C. albicans-infected nematodes and inhibited in vivo filamentation of C. albicans. Two compounds identified in the screen, caffeic acid phenethyl ester, a major active component of honeybee propolis, and the fluoroquinolone agent enoxacin exhibited antifungal activity in a murine model of candidiasis. The whole-animal C. elegans assay may help to study the molecular basis of C. albicans pathogenesis and identify antifungal compounds that most likely would not be identified by in vitro screens that target fungal growth. Compounds identified in the screen that affect the virulence of Candida in vivo can potentially be used as "probe compounds" and may have antifungal activity against other fungi.
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Affiliation(s)
- Julia Breger
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Beth Burgwyn Fuchs
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - George Aperis
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Terence I Moy
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Frederick M Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail:
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Tumbarello M, Posteraro B, Trecarichi EM, Fiori B, Rossi M, Porta R, de Gaetano Donati K, La Sorda M, Spanu T, Fadda G, Cauda R, Sanguinetti M. Biofilm production by Candida species and inadequate antifungal therapy as predictors of mortality for patients with candidemia. J Clin Microbiol 2007; 45:1843-50. [PMID: 17460052 PMCID: PMC1933062 DOI: 10.1128/jcm.00131-07] [Citation(s) in RCA: 259] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nosocomial Candida bloodstream infections rank among infections with highest mortality rates. A retrospective cohort analysis was conducted at Catholic University Hospital to estimate the risk factors for mortality of patients with candidemia. We reviewed records for patients with a Candida bloodstream infection over a 5-year period (January 2000 through December 2004). Two hundred ninety-four patients (42.1% male; mean age +/- standard deviation, 65 +/- 12 years) were studied. Patients most commonly were admitted with a surgical diagnosis (162 patients [55.1%]), had a central venous catheter (213 [72.4%]), cancer (118 [40.1%]), or diabetes (58 [19.7%]). One hundred fifty-four (52.3%) patients died within 30 days. Of 294 patients, 168 (57.1%) were infected by Candida albicans, 64 (21.7%) by Candida parapsilosis, 28 (9.5%) by Candida tropicalis, and 26 (8.8%) by Candida glabrata. When fungal isolates were tested for biofilm formation capacity, biofilm production was most commonly observed for isolates of C. tropicalis (20 of 28 patients [71.4%]), followed by C. glabrata (6 of 26 [23.1%]), C. albicans (38 of 168 [22.6%]), and C. parapsilosis (14 of 64 [21.8%]). Multivariable analysis identified inadequate antifungal therapy (odds ratio [OR], 2.35; 95% confidence interval [95% CI], 1.09 to 5.10; P = 0.03), infection with overall biofilm-forming Candida species (OR, 2.33; 95% CI, 1.26 to 4.30; P = 0.007), and Acute Physiology and Chronic Health Evaluation III scores (OR, 1.03; 95% CI, 1.01 to 1.15; P < 0.001) as independent predictors of mortality. Notably, if mortality was analyzed according to the different biofilm-forming Candida species studied, only infections caused by C. albicans (P < 0.001) and C. parapsilosis (P = 0.003) correlated with increased mortality. Together with well-established factors, Candida biofilm production was therefore shown to be associated with greater mortality of patients with candidemia, probably by preventing complete organism eradication from the blood.
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Affiliation(s)
- Mario Tumbarello
- Institute of Infectious Diseases, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
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686
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He M, Du M, Fan M, Bian Z. In vitro activity of eugenol against Candida albicans biofilms. Mycopathologia 2007; 163:137-43. [PMID: 17356790 DOI: 10.1007/s11046-007-0097-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
Most manifestations of candidiasis are associated with biofilm formation occurring on the surfaces of host tissues and medical devices. Candida albicans is the most frequently isolated causative pathogen of candidiasis, and the biofilms display significantly increased levels of resistance to the conventional antifungal agents. Eugenol, the major phenolic component of clove essential oil, possesses potent antifungal activity. The aim of this study was to investigate the effects of eugenol on preformed biofilms, adherent cells, subsequent biofilm formation and cell morphogenesis of C. albicans. Eugenol displayed in vitro activity against C. albicans cells within biofilms, when MIC(50) for sessile cells was 500 mg/L. C. albicans adherent cell populations (after 0, 1, 2 and 4 h of adherence) were treated with various concentrations of eugenol (0, 20, 200 and 2,000 mg/L). The extent of subsequent biofilm formation were then assessed with the tetrazolium salt reduction assay. Effect of eugenol on morphogenesis of C. albicans cells was observed by scanning electron microscopy (SEM). The results indicated that the effect of eugenol on adherent cells and subsequent biofilm formation was dependent on the initial adherence time and the concentration of this compound, and that eugenol can inhibit filamentous growth of C. albicans cells. In addition, using human erythrocytes, eugenol showed low hemolytic activity. These results indicated that eugenol displayed potent activity against C. albicans biofilms in vitro with low cytotoxicity and therefore has potential therapeutic implication for biofilm-associated candidal infections.
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Affiliation(s)
- Miao He
- Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Luoyu Road 65, Wuhan, 430079, Hubei, China
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687
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Cousins B, Allison H, Doherty P, Edwards C, Garvey M, Martin D, Williams R. Effects of a nanoparticulate silica substrate on cell attachment of Candida albicans. J Appl Microbiol 2007; 102:757-65. [DOI: 10.1111/j.1365-2672.2006.03124.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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688
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Cateau E, Levasseur P, Borgonovi M, Imbert C. The effect of aminocandin (HMR 3270) on the in-vitro adherence of Candida albicans to polystyrene surfaces coated with extracellular matrix proteins or fibronectin. Clin Microbiol Infect 2007; 13:311-5. [PMID: 17391387 DOI: 10.1111/j.1469-0691.2006.01644.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aminocandin is a new representative of the echinocandins that could potentially affect the cellular morphology and metabolic status of Candida albicans cells within biofilms. This study investigated the influence of a sub-inhibitory concentration (MIC/2) of aminocandin on in-vitro growth of C. albicans and subsequent fungal adherence to plastic surfaces coated with fibronectin or extracellular matrix (ECM) proteins. Eleven strains of C. albicans were studied, of which six were susceptible and five were resistant to fluconazole. All 11 strains were susceptible to aminocandin in vitro, regardless of the culture medium used for the microdilution method. Aminocandin induced a significant (p <0.005) decrease in adherence when polystyrene was coated with ECM gel (ten strains) or fibronectin (seven strains). Growth in medium containing aminocandin (MIC/2) decreased the adherence of five (ECM gel) or three (fibronectin) of the six strains susceptible to fluconazole, and inhibition was observed for all five (ECM gel) or four (fibronectin) of the five fluconazole-resistant strains. Overall, the study demonstrated the anti-adherent properties of aminocandin with fluconazole-susceptible strains, and suggested that this activity was at least equivalent with fluconazole-resistant strains. Thus, the ability of aminocandin to inhibit the first step in the development of C. albicans biofilms appeared to be independent of the in-vitro resistance of C. albicans to fluconazole.
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Affiliation(s)
- E Cateau
- Laboratoire de Microbiologie Fondamentale et Appliquée, UMR 6008, Service de Parasitologie, Centre Hospitalier Universitaire La Milétrie, Poitiers, France
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689
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Choi HW, Shin JH, Jung SI, Park KH, Cho D, Kee SJ, Shin MG, Suh SP, Ryang DW. Species-specific differences in the susceptibilities of biofilms formed by Candida bloodstream isolates to echinocandin antifungals. Antimicrob Agents Chemother 2007; 51:1520-3. [PMID: 17283191 PMCID: PMC1855493 DOI: 10.1128/aac.01141-06] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The echinocandin susceptibilities of bloodstream Candida isolates growing in a biofilm was investigated. Within the therapeutic range of concentrations of each drug, caspofungin and micafungin were active against biofilms formed by Candida albicans or C. glabrata but not those formed by C. tropicalis or C. parapsilosis.
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Affiliation(s)
- Hyun Woo Choi
- Department of Laboratory Medicine, Chonnam National University Medical School, 8 Hakdong Dongku, Gwangju 501-757, South Korea
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690
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Krom BP, Cohen JB, McElhaney Feser GE, Cihlar RL. Optimized candidal biofilm microtiter assay. J Microbiol Methods 2007; 68:421-3. [PMID: 17005276 DOI: 10.1016/j.mimet.2006.08.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Revised: 08/01/2006] [Accepted: 08/11/2006] [Indexed: 11/24/2022]
Abstract
Microtiter based candidal biofilm formation is commonly being used. Here we describe the analysis of factors influencing the development of candidal biofilms such as the coating with serum, growth medium and pH. The data reported here show that optimal candidal biofilm formation is obtained when grown in unbuffered YNB at pH 7, in wells that have been coated with Fetal Calf Serum or Fetal Bovine Serum.
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Affiliation(s)
- Bastiaan P Krom
- Department of BioMedical Engineering, University Medical Center Groningen and the University of Groningen, Groningen, The Netherlands.
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691
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Nett J, Lincoln L, Marchillo K, Massey R, Holoyda K, Hoff B, VanHandel M, Andes D. Putative role of beta-1,3 glucans in Candida albicans biofilm resistance. Antimicrob Agents Chemother 2007; 51:510-20. [PMID: 17130296 PMCID: PMC1797745 DOI: 10.1128/aac.01056-06] [Citation(s) in RCA: 270] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 10/17/2006] [Accepted: 11/12/2006] [Indexed: 11/20/2022] Open
Abstract
Biofilms are microbial communities, embedded in a polymeric matrix, growing attached to a surface. Nearly all device-associated infections involve growth in the biofilm life style. Biofilm communities have characteristic architecture and distinct phenotypic properties. The most clinically important phenotype involves extraordinary resistance to antimicrobial therapy, making biofilm infections very difficulty to cure without device removal. The current studies examine drug resistance in Candida albicans biofilms. Similar to previous reports, we observed marked fluconazole and amphotericin B resistance in a C. albicans biofilm both in vitro and in vivo. We identified biofilm-associated cell wall architectural changes and increased beta-1,3 glucan content in C. albicans cell walls from a biofilm compared to planktonic organisms. Elevated beta-1,3 glucan levels were also found in the surrounding biofilm milieu and as part of the matrix both from in vitro and in vivo biofilm models. We thus investigated the possible contribution of beta-glucans to antimicrobial resistance in Candida albicans biofilms. Initial studies examined the ability of cell wall and cell supernatant from biofilm and planktonic C. albicans to bind fluconazole. The cell walls from both environmental conditions bound fluconazole; however, four- to fivefold more compound was bound to the biofilm cell walls. Culture supernatant from the biofilm, but not planktonic cells, bound a measurable amount of this antifungal agent. We next investigated the effect of enzymatic modification of beta-1,3 glucans on biofilm cell viability and the susceptibility of biofilm cells to fluconazole and amphotericin B. We observed a dose-dependent killing of in vitro biofilm cells in the presence of three different beta-glucanase preparations. These same concentrations had no impact on planktonic cell viability. beta-1,3 Glucanase markedly enhanced the activity of both fluconazole and amphotericin B. These observations were corroborated with an in vivo biofilm model. Exogenous biofilm matrix and commercial beta-1,3 glucan reduced the activity of fluconazole against planktonic C. albicans in vitro. In sum, the current investigation identified glucan changes associated with C. albicans biofilm cells, demonstrated preferential binding of these biofilm cell components to antifungals, and showed a positive impact of the modification of biofilm beta-1,3 glucans on drug susceptibility. These results provide indirect evidence suggesting a role for glucans in biofilm resistance and present a strong rationale for further molecular dissection of this resistance mechanism to identify new drug targets to treat biofilm infections.
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Affiliation(s)
- Jeniel Nett
- Department of Medicine, University of Wisconsin Electron Microscopy Facility, Madison 53792, USA
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692
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Becker K, Almasri AS, von Eiff C, Peters G, Heilmann C, Fegeler W. Systematic survey of nonspecific agglutination by Candida spp. in latex assays. J Clin Microbiol 2007; 45:1315-8. [PMID: 17267637 PMCID: PMC1865807 DOI: 10.1128/jcm.01688-06] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to demonstrate that cells of Candida spp. may show considerable nonspecific agglutination in latex agglutination tests, 150 clinical and reference isolates of 12 yeast species were systematically studied by applying various test parameters. In fact, 40 (26.7%) of these isolates revealed nonspecific results, significantly associated with the time allowed for agglutination.
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Affiliation(s)
- Karsten Becker
- Institute of Medical Microbiology, University of Münster, D-48149 Münster, Germany.
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693
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Bruzual I, Riggle P, Hadley S, Kumamoto CA. Biofilm formation by fluconazole-resistant Candida albicans strains is inhibited by fluconazole. J Antimicrob Chemother 2007; 59:441-50. [PMID: 17261564 DOI: 10.1093/jac/dkl521] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The fungal pathogen Candida albicans forms biofilms on implanted medical devices, resulting in infections with high mortality. Fully developed biofilms, which are adherent communities of microorganisms, characteristically exhibit high resistance to antimicrobial drugs, making treatment of device-associated infection problematic. The aim of this study was to determine the effect of the addition of the azole antifungal fluconazole on the initiation of biofilm formation by both drug-susceptible and drug-resistant C. albicans strains. RESULTS Our data reported here show that biofilm formation by both fluconazole-susceptible and fluconazole-resistant C. albicans strains was inhibited when fluconazole was present. For the fluconazole-susceptible strains, inhibition of growth due to the presence of the antifungal drug probably prevented the acquisition of high-level fluconazole resistance. However, for fluconazole-resistant strains, the inhibition of biofilm development was unexpected. CONCLUSIONS Unexpectedly, fluconazole inhibited biofilm formation by a variety of laboratory isolated and clinically isolated fluconazole-resistant strains.
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Affiliation(s)
- Igor Bruzual
- Department of Molecular Biology and Microbiology, Tufts University, 136 Harrison Ave., Boston, MA 02111, USA
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694
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Thomas DP, Bachmann SP, Lopez-Ribot JL. Proteomics for the analysis of the Candida albicans biofilm lifestyle. Proteomics 2007; 6:5795-804. [PMID: 17001605 DOI: 10.1002/pmic.200600332] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Candida albicans is an opportunistic pathogenic fungus capable of causing infections in immunocompromised patients. Candidiasis is often associated with the formation of biofilms on the surface of inert or biological materials. Biofilms are structured microbial communities attached to a surface and encased within a matrix of exopolymeric substance (EPS). At present, very little is known about the changes in protein profiles that occur during the transition from the planktonic to the biofilm mode of growth. Here, we report the use of proteomics for the comparative analysis of subcellular fractions obtained from C. albicans biofilm and planktonic cultures, including cell surface-associated proteins and secreted components present in liquid culture supernatants (for planktonic cultures) and EPS (for biofilms). The analysis revealed a high degree of similarity between the protein profiles associated with the planktonic and biofilm extracts, and led to the identification of several differentially expressed protein spots. Among the differentially expressed proteins, there was a preponderance of metabolic enzymes that have been described as cell surface proteins and immunodominant antigens. Proteins found in the biofilm matrix included a few predicted to form part of the secretome, and also many secretion-signal-less proteins. These observations contribute to our understanding of the C. albicans biofilm lifestyle.
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Affiliation(s)
- Derek P Thomas
- Department of Biology and South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, TX 78249, USA
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695
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Donnelly RF, McCarron PA, Tunney MM, David Woolfson A. Potential of photodynamic therapy in treatment of fungal infections of the mouth. Design and characterisation of a mucoadhesive patch containing toluidine blue O. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2007; 86:59-69. [PMID: 16963273 DOI: 10.1016/j.jphotobiol.2006.07.011] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 07/29/2006] [Accepted: 07/29/2006] [Indexed: 12/31/2022]
Abstract
Mucocutaneous oropharyngeal candidiasis is predominately caused by Candida albicans. The overall incidence of oral candidiasis in young adults has increased dramatically with the spread of HIV/AIDS. Conventional treatments have been shown to have a fungistatic rather than a fungicidal effect, resulting in an inadequate treatment outcome for patients. In addition, increasing resistance of C. albicans to antifungal agents has made effective treatment more difficult. Accordingly, interest has arisen in development of new prophylaxis/treatment regimens. One such alternative treatment is photodynamic antimicrobial chemotherapy (PACT), in which a combination of a photosensitising drug and visible light cause selective destruction of microbial cells. Due to the highly coloured nature of photosensitisers and the potential for staining of teeth, lips and buccal mucosa, administration of photosensitisers to humans as a liquid mouthwash is undesirable. Targeted delivery of the photosensitiser directly to the site of infection should be the aim. The current study, therefore, reports on a mucoadhesive patch containing toluidine blue O (TBO), as a potential delivery system for use in PACT of oropharyngeal candidiasis. Patches prepared from aqueous blends of poly(methyl vinyl ether/maleic anhydride) and tripropyleneglycol methyl ether possessed suitable properties for use as mucoadhesive drug delivery systems and were capable of resisting dissolution when immersed in artificial saliva. When releasing directly into an aqueous sink, patches containing 50 and 100mg TBO cm(-2) both generated receiver compartment concentrations exceeding the concentration (2.0-5.0 mg ml(-1)) required to produce high levels of kill (>90%) of both planktonic and biofilm-grown C. albicans upon illumination. However, the concentrations of TBO in the receiver compartments separated from patches by membranes intended to mimic biofilm structures were an order of magnitude below those inducing high levels of kill, even after 6h release. Therefore, short application times of TBO-containing mucoadhesive patches should allow treatment of recently-acquired oropharyngeal candidiasis, caused solely by planktonic cells. Longer patch application times may be required for persistent disease where biofilms are implicated.
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Affiliation(s)
- Ryan F Donnelly
- School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK.
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696
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Nobile CJ, Nett JE, Andes DR, Mitchell AP. Function of Candida albicans adhesin Hwp1 in biofilm formation. EUKARYOTIC CELL 2006; 5:1604-10. [PMID: 17030992 PMCID: PMC1595337 DOI: 10.1128/ec.00194-06] [Citation(s) in RCA: 277] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hwp1 is a well-characterized Candida albicans cell surface protein, expressed only on hyphae, that mediates tight binding to oral epithelial cells. Prior studies indicate that HWP1 expression is dependent upon Bcr1, a key regulator of biofilm formation. Here we test the hypothesis that Hwp1 is required for biofilm formation. In an in vitro model, the hwp1/hwp1 mutant produces a thin biofilm that lacks much of the hyphal mass found in the hwp1/HWP1 reconstituted strain. In a biofilm cell retention assay, we find that the hwp1/hwp1 mutant is defective in retention of nonadherent bcr1/bcr1 mutant cells. In an in vivo rat venous catheter model, the hwp1/hwp1 mutant has a severe biofilm defect, yielding only yeast microcolonies in the catheter lumen. These properties of the hwp1/hwp1 mutant are consistent with its role as a hypha-specific adhesin and indicate that it is required for normal biofilm formation. Overexpression of HWP1 in a bcr1/bcr1 mutant background improves adherence in the in vivo catheter model. This finding provides additional support for the model that Hwp1 is critical for biofilm adhesion. Hwp1 is the first cell surface protein known to be required for C. albicans biofilm formation in vivo and is thus an excellent therapeutic target.
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Affiliation(s)
- Clarissa J Nobile
- Department of Microbiology, Columbia University, New York, NY 10032, USA
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697
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Blankenship JR, Mitchell AP. How to build a biofilm: a fungal perspective. Curr Opin Microbiol 2006; 9:588-94. [PMID: 17055772 DOI: 10.1016/j.mib.2006.10.003] [Citation(s) in RCA: 369] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 10/10/2006] [Indexed: 11/24/2022]
Abstract
Biofilms are differentiated masses of microbes that form on surfaces and are surrounded by an extracellular matrix. Fungal biofilms, especially those of the pathogen Candida albicans, are a cause of infections associated with medical devices. Such infections are particularly serious because biofilm cells are relatively resistant to many common antifungal agents. Several in vitro models have been used to elucidate the developmental stages and processes required for C. albicans biofilm formation, and recent studies have begun to define biofilm genetic control. It is clear that cell-substrate and cell-cell interactions, hyphal differentiation and extracellular matrix production are key steps in biofilm development. Drug resistance is acquired early in biofilm formation, and appears to be governed by different mechanisms in early and late biofilms. Quorum sensing might be an important factor in dispersal of biofilm cells. The past two years have seen the emergence of several genomic strategies to uncover global events in biofilm formation and directed studies to understand more specific events, such as hyphal formation, in the biofilm setting.
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Affiliation(s)
- Jill R Blankenship
- Department of Microbiology, Hammer Health Sciences Center, Room 906, 701 W 168th Street, New York, NY 10032, USA
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698
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Seidler M, Salvenmoser S, Müller FMC. In vitro effects of micafungin against Candida biofilms on polystyrene and central venous catheter sections. Int J Antimicrob Agents 2006; 28:568-73. [PMID: 17101265 DOI: 10.1016/j.ijantimicag.2006.07.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 07/27/2006] [Accepted: 07/28/2006] [Indexed: 11/21/2022]
Abstract
Long-term inserted and surgically implanted catheters can be colonised by Candida spp. Candida biofilms in vitro are often resistant to antifungal agents. The aim of this study was to investigate the in vitro activity of micafungin (MFG) against six Candida spp. biofilms on polystyrene (PS) and central venous catheter (CVC) sections. Safranin staining and differential interference contrast microscopy were used to demonstrate biofilm production. MFG activity was determined by the reduction in metabolic activity (%RMA) by tetrazolium reduction assay on both substrates. In vitro, Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida dubliniensis and Candida kefyr produced mature biofilms on PS and CVC sections. MFG was active against C. kefyr (0.5 microg/mL) and C. glabrata (<0.5 microg/mL) on PS. However, MFG displayed resistance (>16 microg/mL) against C. albicans, C. dubliniensis,C. tropicalis and C. parapsilosis. On CVC disks, MFG was active against C. glabrata (1 microg/mL) as well as C. parapsilosis and C. albicans (<0.5 microg/mL). MFG was resistant (>16 microg/mL) against C. dubliniensis, C. tropicalis and C. kefyr. MFG was active in vitro against all six Candida spp. on both substrates. However, MFG could not reduce the metabolic activity completely even at the highest concentration.
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Affiliation(s)
- Marc Seidler
- Department of Paediatrics, Paediatric Pulmonology and Infectious Diseases, University of Heidelberg, Im Neuenheimer Feld 153, D-69120 Heidelberg, Germany
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699
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Khot PD, Suci PA, Miller RL, Nelson RD, Tyler BJ. A small subpopulation of blastospores in candida albicans biofilms exhibit resistance to amphotericin B associated with differential regulation of ergosterol and beta-1,6-glucan pathway genes. Antimicrob Agents Chemother 2006; 50:3708-16. [PMID: 16966398 PMCID: PMC1635220 DOI: 10.1128/aac.00997-06] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The resistance of Candida albicans biofilms to a broad spectrum of antimicrobial agents has been well documented. Biofilms are known to be heterogeneous, consisting of microenvironments that may induce formation of resistant subpopulations. In this study we characterized one such subpopulation. C. albicans biofilms were cultured in a tubular flow cell (TF) for 36 h. The relatively large shear forces imposed by draining the TF removed most of the biofilm, which consisted of a tangled mass of filamentous forms with associated clusters of yeast forms. This portion of the biofilm exhibited the classic architecture and morphological heterogeneity of a C. albicans biofilm and was only slightly more resistant than either exponential- or stationary-phase planktonic cells. A submonolayer fraction of blastospores that remained on the substratum was resistant to 10 times the amphotericin B dose that eliminated the activity of the planktonic populations. A comparison between planktonic and biofilm populations of transcript abundance for genes coding for enzymes in the ergosterol (ERG1, -3, -5, -6, -9, -11, and -25) and beta-1,6-glucan (SKN and KRE1, -5, -6, and -9) pathways was performed by quantitative RT-PCR. The results indicate a possible association between the high level of resistance exhibited by the blastospore subpopulation and differential regulation of ERG1, ERG25, SKN1, and KRE1. We hypothesize that the resistance originates from a synergistic effect involving changes in both the cell membrane and the cell wall.
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MESH Headings
- Amphotericin B/pharmacology
- Antifungal Agents/pharmacology
- Biofilms/drug effects
- Candida albicans/drug effects
- Candida albicans/genetics
- Candida albicans/ultrastructure
- DNA Primers
- DNA, Complementary/biosynthesis
- DNA, Complementary/genetics
- DNA, Fungal/biosynthesis
- DNA, Fungal/genetics
- Drug Resistance, Fungal/physiology
- Ergosterol/genetics
- Ergosterol/metabolism
- Genes, Fungal/genetics
- Microbial Sensitivity Tests
- Microscopy, Electron, Scanning
- RNA, Fungal/biosynthesis
- RNA, Fungal/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Spores, Fungal/drug effects
- Spores, Fungal/genetics
- Spores, Fungal/ultrastructure
- Transcription, Genetic
- beta-Glucans/metabolism
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Affiliation(s)
- Prasanna D Khot
- Department of Microbiology and Center for Biofilm Engineering, 366 EPS, Montana State University, Bozeman, MT 59717-3980, USA
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700
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Mukherjee PK, Mohamed S, Chandra J, Kuhn D, Liu S, Antar OS, Munyon R, Mitchell AP, Andes D, Chance MR, Rouabhia M, Ghannoum MA. Alcohol dehydrogenase restricts the ability of the pathogen Candida albicans to form a biofilm on catheter surfaces through an ethanol-based mechanism. Infect Immun 2006; 74:3804-16. [PMID: 16790752 PMCID: PMC1489753 DOI: 10.1128/iai.00161-06] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida biofilms formed on indwelling medical devices are increasingly associated with severe infections. In this study, we used proteomics and Western and Northern blotting analyses to demonstrate that alcohol dehydrogenase (ADH) is downregulated in Candida biofilms. Disruption of ADH1 significantly (P = 0.0046) enhanced the ability of Candida albicans to form biofilm. Confocal scanning laser microscopy showed that the adh1 mutant formed thicker biofilm than the parent strain (210 microm and 140 microm, respectively). These observations were extended to an engineered human oral mucosa and an in vivo rat model of catheter-associated biofilm. Inhibition of Candida ADH enzyme using disulfiram and 4-methylpyrazole resulted in thicker biofilm (P < 0.05). Moreover, biofilms formed by the adh1 mutant strain produced significantly smaller amounts of ethanol, but larger amounts of acetaldehyde, than biofilms formed by the parent and revertant strains (P < 0.0001), demonstrating that the effect of Adh1p on biofilm formation is mediated by its enzymatic activity. Furthermore, we found that 10% ethanol significantly inhibited biofilm formation in vitro, with complete inhibition of biofilm formation at ethanol concentrations of >/=20%. Similarly, using a clinically relevant rabbit model of catheter-associated biofilm, we found that ethanol treatment inhibited biofilm formation by C. albicans in vivo (P < 0.05) but not by Staphylococcus spp. (P > 0.05), indicating that ethanol specifically inhibits Candida biofilm formation. Taken together, our studies revealed that Adh1p contributes to the ability of C. albicans to form biofilms in vitro and in vivo and that the protein restricts biofilm formation through an ethanol-dependent mechanism. These results are clinically relevant and may suggest novel antibiofilm treatment strategies.
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Affiliation(s)
- Pranab K Mukherjee
- Center for Medical Mycology, Department of Dermatology, Case Western Reserve University, 11100 Euclid Avenue, LKS-5028, Cleveland, OH 44106, USA
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