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Kumar D, Kumar A. Cellular Attributes of Candida albicans Biofilm-Associated in Resistance Against Multidrug and Host Immune System. Microb Drug Resist 2023; 29:423-437. [PMID: 37428599 DOI: 10.1089/mdr.2022.0347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023] Open
Abstract
One of the ubiquitous hospital-acquired infections is associated with Candida albicans fungus. Usually, this commensal fungus causes no harm to its human host, as it lives mutually with mucosal/epithelial tissue surface cells. Nevertheless, due to the activity of various immune weakening factors, this commensal starts reinforcing its virulence attributes with filamentation/hyphal growth and building an absolute microcolony composed of yeast, hyphal, and pseudohyphal cells, which is suspended in an extracellular gel-like polymeric substance (EPS) called biofilms. This polymeric substance is the mixture of the secreted compounds from C. albicans as well as several host cell proteins. Indeed, the presence of these host factors makes their identification and differentiation process difficult by host immune components. The gel-like texture of the EPS makes it sticky, which adsorbs most of the extracolonial compounds traversing through it that aid in penetration hindrance. All these factors further contribute to the multidrug resistance phenotype of C. albicans biofilm that is spotlighted in this article. The mechanisms it employs to escape the host immune system are also addressed effectively. The article focuses on cellular and molecular determinants involved in the resistance of C. albicans biofilm against multidrug and the host immune system.
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Affiliation(s)
- Dushyant Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, India
| | - Awanish Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, India
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2
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Roudbary M, Vahedi-Shahandashti R, Santos ALSD, Roudbar Mohammadi S, Aslani P, Lass-Flörl C, Rodrigues CF. Biofilm formation in clinically relevant filamentous fungi: a therapeutic challenge. Crit Rev Microbiol 2021; 48:197-221. [PMID: 34358430 DOI: 10.1080/1040841x.2021.1950121] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Biofilms are highly-organized microbial communities attached to a biotic or an abiotic surface, surrounded by an extracellular matrix secreted by the biofilm-forming cells. The majority of fungal pathogens contribute to biofilm formation within tissues or biomedical devices, leading to serious and persistent infections. The clinical significance of biofilms relies on the increased resistance to conventional antifungal therapies and suppression of the host immune system, which leads to invasive and recurrent fungal infections. While different features of yeast biofilms are well-described in the literature, the structural and molecular basis of biofilm formation of clinically related filamentous fungi has not been fully addressed. This review aimed to address biofilm formation in clinically relevant filamentous fungi.
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Affiliation(s)
- Maryam Roudbary
- Department of Parasitology and Mycology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | | | - André Luis Souza Dos Santos
- Department of General Microbiology, Microbiology Institute Paulo de Góes, Federal University of Rio de Janeiro (UFRJ), Brazil
| | | | - Peyman Aslani
- Department of Parasitology and Mycology, Faculty of Medicine, Aja University of Medical Sciences, Tehran, Iran
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University Innsbruck, Innsbruck, Austria
| | - Célia F Rodrigues
- LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
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3
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Rao H, Choo S, Rajeswari Mahalingam SR, Adisuri DS, Madhavan P, Md. Akim A, Chong PP. Approaches for Mitigating Microbial Biofilm-Related Drug Resistance: A Focus on Micro- and Nanotechnologies. Molecules 2021; 26:1870. [PMID: 33810292 PMCID: PMC8036581 DOI: 10.3390/molecules26071870] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/03/2021] [Accepted: 02/09/2021] [Indexed: 02/07/2023] Open
Abstract
Biofilms play an essential role in chronic and healthcare-associated infections and are more resistant to antimicrobials compared to their planktonic counterparts due to their (1) physiological state, (2) cell density, (3) quorum sensing abilities, (4) presence of extracellular matrix, (5) upregulation of drug efflux pumps, (6) point mutation and overexpression of resistance genes, and (7) presence of persister cells. The genes involved and their implications in antimicrobial resistance are well defined for bacterial biofilms but are understudied in fungal biofilms. Potential therapeutics for biofilm mitigation that have been reported include (1) antimicrobial photodynamic therapy, (2) antimicrobial lock therapy, (3) antimicrobial peptides, (4) electrical methods, and (5) antimicrobial coatings. These approaches exhibit promising characteristics for addressing the impending crisis of antimicrobial resistance (AMR). Recently, advances in the micro- and nanotechnology field have propelled the development of novel biomaterials and approaches to combat biofilms either independently, in combination or as antimicrobial delivery systems. In this review, we will summarize the general principles of clinically important microbial biofilm formation with a focus on fungal biofilms. We will delve into the details of some novel micro- and nanotechnology approaches that have been developed to combat biofilms and the possibility of utilizing them in a clinical setting.
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Affiliation(s)
- Harinash Rao
- School of Medicine, Taylor’s University, Subang Jaya, Selangor 47500, Malaysia; (H.R.); (D.S.A.); (P.M.)
| | - Sulin Choo
- School of Biosciences, Taylor’s University, Subang Jaya, Selangor 47500, Malaysia;
| | | | - Diajeng Sekar Adisuri
- School of Medicine, Taylor’s University, Subang Jaya, Selangor 47500, Malaysia; (H.R.); (D.S.A.); (P.M.)
| | - Priya Madhavan
- School of Medicine, Taylor’s University, Subang Jaya, Selangor 47500, Malaysia; (H.R.); (D.S.A.); (P.M.)
| | - Abdah Md. Akim
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor 43400, Malaysia
| | - Pei Pei Chong
- School of Biosciences, Taylor’s University, Subang Jaya, Selangor 47500, Malaysia;
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4
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Demin KA, Refeld AG, Bogdanova AA, Prazdnova EV, Popov IV, Kutsevalova OY, Ermakov AM, Bren AB, Rudoy DV, Chistyakov VA, Weeks R, Chikindas ML. Mechanisms of Candida Resistance to Antimycotics and Promising Ways to Overcome It: The Role of Probiotics. Probiotics Antimicrob Proteins 2021; 13:926-948. [PMID: 33738706 DOI: 10.1007/s12602-021-09776-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2021] [Indexed: 12/12/2022]
Abstract
Pathogenic Candida and infections caused by those species are now considered as a serious threat to public health. The treatment of candidiasis is significantly complicated by the increasing resistance of pathogenic strains to current treatments and the stagnant development of new antimycotic drugs. Many species, such as Candida auris, have a wide range of resistance mechanisms. Among the currently used synthetic and semi-synthetic antifungal drugs, the most effective are azoles, echinocandins, polyenes, nucleotide analogs, and their combinations. However, the use of probiotic microorganisms and/or the compounds they produce is quite promising, although underestimated by modern pharmacology, to control the spread of pathogenic Candida species.
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Affiliation(s)
- Konstantin A Demin
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Aleksandr G Refeld
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Anna A Bogdanova
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Evgenya V Prazdnova
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Igor V Popov
- Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia
| | | | - Alexey M Ermakov
- Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia
| | - Anzhelica B Bren
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia.,Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia
| | - Dmitry V Rudoy
- Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia
| | - Vladimir A Chistyakov
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Richard Weeks
- Health Promoting Naturals Laboratory, School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ, USA
| | - Michael L Chikindas
- Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia. .,Health Promoting Naturals Laboratory, School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ, USA. .,I.M. Sechenov First Moscow State Medical University, Moscow, Russia.
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5
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Pereira R, Dos Santos Fontenelle RO, de Brito EHS, de Morais SM. Biofilm of Candida albicans: formation, regulation and resistance. J Appl Microbiol 2020; 131:11-22. [PMID: 33249681 DOI: 10.1111/jam.14949] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/10/2020] [Accepted: 11/25/2020] [Indexed: 12/15/2022]
Abstract
Candida albicans is the most common human fungal pathogen, causing infections that range from mucous membranes to systemic infections. The present article provides an overview of C. albicans, with the production of biofilms produced by this fungus, as well as reporting the classes of antifungals used to fight such infections, together with the resistance mechanisms to these drugs. Candida albicans is highly adaptable, enabling the transition from commensal to pathogen due to a repertoire of virulence factors. Specifically, the ability to change morphology and form biofilms is central to the pathogenesis of C. albicans. Indeed, most infections by this pathogen are associated with the formation of biofilms on surfaces of hosts or medical devices, causing high morbidity and mortality. Significantly, biofilms formed by C. albicans are inherently tolerant to antimicrobial therapy, so the susceptibility of C. albicans biofilms to current therapeutic agents remains low. Therefore, it is difficult to predict which molecules will emerge as new clinical antifungals. The biofilm formation of C. albicans has been causing impacts on susceptibility to antifungals, leading to resistance, which demonstrates the importance of research aimed at the prevention and control of these clinical microbial communities.
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Affiliation(s)
- R Pereira
- Graduate Program in Biotechnology, Microbiology Laboratory (LABMIC), Vale do Acaraú State University, Sobral, Ceará, Brazil
| | | | - E H S de Brito
- Institute of Health Sciences of University for International Integration of Afro-Brazilian Lusophony, Redenção, Ceará, Brazil
| | - S M de Morais
- Graduate Program in Biotechnology, Laboratory of Chemistry of Natural Products (LQPN), Ceará State University, Fortaleza, Ceará, Brazil
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Nev OA, Jepson A, Beardmore RE, Gudelj I. Predicting community dynamics of antibiotic-sensitive and -resistant species in fluctuating environments. J R Soc Interface 2020; 17:20190776. [PMID: 32453982 DOI: 10.1098/rsif.2019.0776] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Microbes occupy almost every niche within and on their human hosts. Whether colonizing the gut, mouth or bloodstream, microorganisms face temporal fluctuations in resources and stressors within their niche but we still know little of how environmental fluctuations mediate certain microbial phenotypes, notably antimicrobial-resistant ones. For instance, do rapid or slow fluctuations in nutrient and antimicrobial concentrations select for, or against, resistance? We tackle this question using an ecological approach by studying the dynamics of a synthetic and pathogenic microbial community containing two species, one sensitive and the other resistant to an antibiotic drug where the community is exposed to different rates of environmental fluctuation. We provide mathematical models, supported by experimental data, to demonstrate that simple community outcomes, such as competitive exclusion, can shift to coexistence and ecosystem bistability as fluctuation rates vary. Theory gives mechanistic insight into how these dynamical regimes are related. Importantly, our approach highlights a fundamental difference between resistance in single-species populations, the context in which it is usually assayed, and that in communities. While fast environmental changes are known to select against resistance in single-species populations, here we show that they can promote the resistant species in mixed-species communities. Our theoretical observations are verified empirically using a two-species Candida community.
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Affiliation(s)
- Olga A Nev
- Biosciences and Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK
| | - Alys Jepson
- Biosciences and Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK
| | - Robert E Beardmore
- Biosciences and Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK
| | - Ivana Gudelj
- Biosciences and Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK
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7
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Shareef MA, Sirisha K, Khan I, Sayeed IB, Jadav SS, Ramu G, Kumar CG, Kamal A, Babu BN. Design, synthesis, and antimicrobial evaluation of 1,4-dihydroindeno[1,2- c]pyrazole tethered carbohydrazide hybrids: exploring their in silico ADMET, ergosterol inhibition and ROS inducing potential. MEDCHEMCOMM 2019; 10:806-813. [PMID: 31191871 PMCID: PMC6540956 DOI: 10.1039/c9md00155g] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 03/29/2019] [Indexed: 11/21/2022]
Abstract
A series of new 1,4-dihydroindeno[1,2-c]pyrazole tethered carbohydrazide hybrids (5a-u) were designed, synthesized and evaluated for their antimicrobial activity. Compounds 5d, 5g, 5j, 5k and 5q demonstrated significant activity against the entire panel of test pathogens. Further, compounds 5d and 5g exhibited significant anti-Candida activity. These potential hybrids (5d and 5g) also exhibited promising ergosterol biosynthesis inhibition against Candida albicans, which was further validated through molecular docking studies. Furthermore, compounds 5d and 5g caused intracellular ROS accumulation in C. albicans MTCC 3017 and were non-toxic to normal human lung cell line MRC5. In silico studies revealed that they demonstrated drug likeness and an appreciable pharmacokinetic profile. Overall, the findings demonstrate that 5d and 5g may be considered as promising leads for further development of new antifungal drugs.
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Affiliation(s)
- Mohd Adil Shareef
- Department of Fluoro-Agrochemicals , CSIR-Indian Institute of Chemical Technology , Tarnaka , Hyderabad , India .
- Academy of Scientific and Innovative Research , New Delhi 110 025 , India
| | - K Sirisha
- Academy of Scientific and Innovative Research , New Delhi 110 025 , India
- Organic Synthesis and Process Chemistry Division , CSIR-Indian Institute of Chemical Technology , Tarnaka , Hyderabad 500007 , India
| | - Irfan Khan
- Academy of Scientific and Innovative Research , New Delhi 110 025 , India
- Organic Synthesis and Process Chemistry Division , CSIR-Indian Institute of Chemical Technology , Tarnaka , Hyderabad 500007 , India
| | - Ibrahim Bin Sayeed
- Academy of Scientific and Innovative Research , New Delhi 110 025 , India
- Organic Synthesis and Process Chemistry Division , CSIR-Indian Institute of Chemical Technology , Tarnaka , Hyderabad 500007 , India
| | - Surender Singh Jadav
- Department of Fluoro-Agrochemicals , CSIR-Indian Institute of Chemical Technology , Tarnaka , Hyderabad , India .
| | - Gopathi Ramu
- Department of Fluoro-Agrochemicals , CSIR-Indian Institute of Chemical Technology , Tarnaka , Hyderabad , India .
- Academy of Scientific and Innovative Research , New Delhi 110 025 , India
| | - C Ganesh Kumar
- Organic Synthesis and Process Chemistry Division , CSIR-Indian Institute of Chemical Technology , Tarnaka , Hyderabad 500007 , India
| | - Ahmed Kamal
- School of Pharmaceutical Education and Research , Jamia Hamdard University , New Delhi 110062 , India .
| | - Bathini Nagendra Babu
- Department of Fluoro-Agrochemicals , CSIR-Indian Institute of Chemical Technology , Tarnaka , Hyderabad , India .
- Academy of Scientific and Innovative Research , New Delhi 110 025 , India
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8
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Iron Restriction to Clinical Isolates of Candida albicans by the Novel Chelator DIBI Inhibits Growth and Increases Sensitivity to Azoles In Vitro and In Vivo in a Murine Model of Experimental Vaginitis. Antimicrob Agents Chemother 2018; 62:AAC.02576-17. [PMID: 29844048 DOI: 10.1128/aac.02576-17] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/19/2018] [Indexed: 12/22/2022] Open
Abstract
Candida albicans is an important opportunistic pathogen causing various human infections that are often treated with azole antifungals. The U.S. CDC now regards developing candidal antifungal resistance as a threat, creating a need for new and more effective antifungal treatments. Iron is an essential nutrient for all living cells, and there is growing evidence that interference with iron homeostasis of C. albicans can improve its response to antifungals. This study was aimed at establishing whether withholding iron by currently used medical iron chelators and the novel chelator DIBI could restrict growth and also enhance the activity of azoles against clinical isolates of C. albicans DIBI, but not deferoxamine or deferiprone, inhibited the growth of C. albicans at relatively low concentrations in vitro, and this inhibition was reversed by iron addition. DIBI in combination with various azoles demonstrated stronger growth inhibition than the azoles alone and greatly prolonged the inhibition of cell multiplication. In addition, the administration of DIBI along with fluconazole (FLC) to mice inoculated with an FLC-sensitive isolate in a model of experimental C. albicans vaginitis showed a markedly improved clearance of infection. These results suggest that iron chelation by DIBI has the potential to enhance azole efficacy for the treatment of candidiasis.
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Fourie R, Kuloyo OO, Mochochoko BM, Albertyn J, Pohl CH. Iron at the Centre of Candida albicans Interactions. Front Cell Infect Microbiol 2018; 8:185. [PMID: 29922600 PMCID: PMC5996042 DOI: 10.3389/fcimb.2018.00185] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 05/14/2018] [Indexed: 12/27/2022] Open
Abstract
Iron is an absolute requirement for both the host and most pathogens alike and is needed for normal cellular growth. The acquisition of iron by biological systems is regulated to circumvent toxicity of iron overload, as well as the growth deficits imposed by iron deficiency. In addition, hosts, such as humans, need to limit the availability of iron to pathogens. However, opportunistic pathogens such as Candida albicans are able to adapt to extremes of iron availability, such as the iron replete environment of the gastrointestinal tract and iron deficiency during systemic infection. C. albicans has developed a complex and effective regulatory circuit for iron acquisition and storage to circumvent iron limitation within the human host. As C. albicans can form complex interactions with both commensal and pathogenic co-inhabitants, it can be speculated that iron may play an important role in these interactions. In this review, we highlight host iron regulation as well as regulation of iron homeostasis in C. albicans. In addition, the review argues for the need for further research into the role of iron in polymicrobial interactions. Lastly, the role of iron in treatment of C. albicans infection is discussed.
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Affiliation(s)
- Ruan Fourie
- Pathogenic Yeast Research Group, Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
| | - Oluwasegun O Kuloyo
- Pathogenic Yeast Research Group, Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
| | - Bonang M Mochochoko
- Pathogenic Yeast Research Group, Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
| | - Jacobus Albertyn
- Pathogenic Yeast Research Group, Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
| | - Carolina H Pohl
- Pathogenic Yeast Research Group, Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa
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Dühring S, Ewald J, Germerodt S, Kaleta C, Dandekar T, Schuster S. Modelling the host-pathogen interactions of macrophages and Candida albicans using Game Theory and dynamic optimization. J R Soc Interface 2018; 14:rsif.2017.0095. [PMID: 28701506 PMCID: PMC5550964 DOI: 10.1098/rsif.2017.0095] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/16/2017] [Indexed: 12/21/2022] Open
Abstract
The release of fungal cells following macrophage phagocytosis, called non-lytic expulsion, is reported for several fungal pathogens. On one hand, non-lytic expulsion may benefit the fungus in escaping the microbicidal environment of the phagosome. On the other hand, the macrophage could profit in terms of avoiding its own lysis and being able to undergo proliferation. To analyse the causes of non-lytic expulsion and the relevance of macrophage proliferation in the macrophage–Candida albicans interaction, we employ Evolutionary Game Theory and dynamic optimization in a sequential manner. We establish a game-theoretical model describing the different strategies of the two players after phagocytosis. Depending on the parameter values, we find four different Nash equilibria and determine the influence of the systems state of the host upon the game. As our Nash equilibria are a direct consequence of the model parameterization, we can depict several biological scenarios. A parameter region, where the host response is robust against the fungal infection, is determined. We further apply dynamic optimization to analyse whether macrophage mitosis is relevant in the host–pathogen interaction of macrophages and C. albicans. For this, we study the population dynamics of the macrophage–C. albicans interactions and the corresponding optimal controls for the macrophages, indicating the best macrophage strategy of switching from proliferation to attacking fungal cells.
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Affiliation(s)
- Sybille Dühring
- Department of Bioinformatics, Friedrich-Schiller-University Jena, Jena, Germany
| | - Jan Ewald
- Department of Bioinformatics, Friedrich-Schiller-University Jena, Jena, Germany
| | - Sebastian Germerodt
- Department of Bioinformatics, Friedrich-Schiller-University Jena, Jena, Germany
| | - Christoph Kaleta
- Research Group Medical Systems Biology, Institute for Experimental Medicine, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Thomas Dandekar
- Biocenter, Department of Bioinformatics, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Stefan Schuster
- Department of Bioinformatics, Friedrich-Schiller-University Jena, Jena, Germany
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11
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Alves R, Mota S, Silva S, F Rodrigues C, P Brown AJ, Henriques M, Casal M, Paiva S. The carboxylic acid transporters Jen1 and Jen2 affect the architecture and fluconazole susceptibility of Candida albicans biofilm in the presence of lactate. BIOFOULING 2017; 33:943-954. [PMID: 29094611 DOI: 10.1080/08927014.2017.1392514] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/10/2017] [Indexed: 06/07/2023]
Abstract
Candida albicans has the ability to adapt to different host niches, often glucose-limited but rich in alternative carbon sources. In these glucose-poor microenvironments, this pathogen expresses JEN1 and JEN2 genes, encoding carboxylate transporters, which are important in the early stages of infection. This work investigated how host microenvironments, in particular acidic containing lactic acid, affect C. albicans biofilm formation and antifungal drug resistance. Multiple components of the extracellular matrix were also analysed, including their impact on antifungal drug resistance, and the involvement of both Jen1 and Jen2 in this process. The results show that growth on lactate affects biofilm formation, morphology and susceptibility to fluconazole and that both Jen1 and Jen2 might play a role in these processes. These results support the view that the adaptation of Candida cells to the carbon source present in the host niches affects their pathogenicity.
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Affiliation(s)
- Rosana Alves
- a Centre of Molecular and Environmental Biology, Department of Biology , University of Minho , Braga , Portugal
| | - Sandra Mota
- a Centre of Molecular and Environmental Biology, Department of Biology , University of Minho , Braga , Portugal
- b Centre of Health and Environmental Research, School of Allied Health Sciences , Polytechnic Institute of Porto , Porto , Portugal
| | - Sónia Silva
- c Centre of Biological Engineering , LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
| | - Célia F Rodrigues
- c Centre of Biological Engineering , LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
| | - Alistair J P Brown
- d MRC Centre for Medical Mycology , Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen , Aberdeen , UK
| | - Mariana Henriques
- c Centre of Biological Engineering , LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho , Braga , Portugal
| | - Margarida Casal
- a Centre of Molecular and Environmental Biology, Department of Biology , University of Minho , Braga , Portugal
| | - Sandra Paiva
- a Centre of Molecular and Environmental Biology, Department of Biology , University of Minho , Braga , Portugal
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12
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Rodrigues CF, Rodrigues ME, Silva S, Henriques M. Candida glabrata Biofilms: How Far Have We Come? J Fungi (Basel) 2017; 3:E11. [PMID: 29371530 PMCID: PMC5715960 DOI: 10.3390/jof3010011] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/07/2017] [Accepted: 02/16/2017] [Indexed: 11/25/2022] Open
Abstract
Infections caused by Candida species have been increasing in the last decades and can result in local or systemic infections, with high morbidity and mortality. After Candida albicans, Candida glabrata is one of the most prevalent pathogenic fungi in humans. In addition to the high antifungal drugs resistance and inability to form hyphae or secret hydrolases, C. glabrata retain many virulence factors that contribute to its extreme aggressiveness and result in a low therapeutic response and serious recurrent candidiasis, particularly biofilm formation ability. For their extraordinary organization, especially regarding the complex structure of the matrix, biofilms are very resistant to antifungal treatments. Thus, new approaches to the treatment of C. glabrata's biofilms are emerging. In this article, the knowledge available on C. glabrata's resistance will be highlighted, with a special focus on biofilms, as well as new therapeutic alternatives to control them.
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Affiliation(s)
- Célia F Rodrigues
- CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
| | - Maria Elisa Rodrigues
- CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
| | - Sónia Silva
- CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
| | - Mariana Henriques
- CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
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13
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Silva S, Rodrigues CF, Araújo D, Rodrigues ME, Henriques M. Candida Species Biofilms' Antifungal Resistance. J Fungi (Basel) 2017; 3:jof3010008. [PMID: 29371527 PMCID: PMC5715972 DOI: 10.3390/jof3010008] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 01/30/2017] [Accepted: 02/09/2017] [Indexed: 12/28/2022] Open
Abstract
Candida infections (candidiasis) are the most prevalent opportunistic fungal infection on humans and, as such, a major public health problem. In recent decades, candidiasis has been associated to Candida species other than Candida albicans. Moreover, biofilms have been considered the most prevalent growth form of Candida cells and a strong causative agent of the intensification of antifungal resistance. As yet, no specific resistance factor has been identified as the sole responsible for the increased recalcitrance to antifungal agents exhibited by biofilms. Instead, biofilm antifungal resistance is a complex multifactorial phenomenon, which still remains to be fully elucidated and understood. The different mechanisms, which may be responsible for the intrinsic resistance of Candida species biofilms, include the high density of cells within the biofilm, the growth and nutrient limitation, the effects of the biofilm matrix, the presence of persister cells, the antifungal resistance gene expression and the increase of sterols on the membrane of biofilm cells. Thus, this review intends to provide information on the recent advances about Candida species biofilm antifungal resistance and its implication on intensification of the candidiasis.
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Affiliation(s)
- Sónia Silva
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Célia F Rodrigues
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Daniela Araújo
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Maria Elisa Rodrigues
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Mariana Henriques
- Centre of Biological Engineering (CEB), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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Abstract
Candida albicans is the most common human fungal pathogen causing diseases ranging from mucosal to systemic infections. As a commensal, C. albicans asymptomatically colonizes mucosal surfaces; however, any disruption in the host environment or under conditions of immune dysfunction, C. albicans can proliferate and invade virtually any site in the host. The ability of this highly adaptable fungal species to transition from commensal to pathogen is due to a repertoire of virulence factors. Specifically, the ability to switch morphology and form biofilms are properties central to C. albicans pathogenesis. In fact, the majority of C. albicans infections are associated with biofilm formation on host or abiotic surfaces such as indwelling medical devices, which carry high morbidity and mortality. Significantly, biofilms formed by C. albicans are inherently tolerant to antimicrobial therapy and therefore, the susceptibility of Candida biofilms to the current therapeutic agents remains low. The aim of this review is to provide an overview of C. albicans highlighting some of the diverse biofilm-associated diseases caused by this opportunistic pathogen and the animal models available to study them. Further, the classes of antifungal agents used to combat these resilient infections are discussed along with mechanisms of drug resistance.
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Chudzik B, Miaskowski A, Surowiec Z, Czernel G, Duluk T, Marczuk A, Gagoś M. Effectiveness of magnetic fluid hyperthermia against Candida albicans cells. Int J Hyperthermia 2016; 32:842-857. [PMID: 27418322 DOI: 10.1080/02656736.2016.1212277] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Candida albicans is one of the most frequently isolated fungal pathogens causing opportunistic infections in humans. Targeted magnetic fluid hyperthermia (MFH) is a promising method in thermal therapy facilitating selective heating of pathogen cells like C. albicans. In the paper, we used meso-2,3-dimercaptosuccinic acid (DMSA)-coated magnetic nanoparticles (MNPs) and functionalised anti-C. albicans immunomagnetic nanoparticles (IMNPs) to investigate the potential of MFH in combating C. albicans cells in vitro. Using Mössbauer spectroscopy it was found that synthesised MNPs exhibited superparamagnetic phenomena. On the basis of calorimetric experiments, the maximum SAR (specific absorption rate) was found and a proper concentration of MNPs was established to control the temperature. MFH based on both DMSA-coated MNPs and functionalised anti-C. albicans IMNPs was more effective in combating C. albicans cells in vitro than thermostat hyperthermia. Especially promising results were obtained using functionalised IMNPs, which eradicated most of the pathogen colonies at the temperature of 43 °C.
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Affiliation(s)
- Barbara Chudzik
- a Department of Cell Biology , Maria Curie-Skłodowska University , Lublin , Poland
| | - Arkadiusz Miaskowski
- b Department of Applied Mathematics and Computer Science , University of Life Sciences , Lublin , Poland
| | - Zbigniew Surowiec
- c Faculty of Mathematics, Physics and Computer Science , Maria Curie-Skłodowska University , Lublin , Poland
| | - Grzegorz Czernel
- d Department of Physics , University of Life Sciences in Lublin , Lublin , Poland
| | - Tomasz Duluk
- a Department of Cell Biology , Maria Curie-Skłodowska University , Lublin , Poland
| | - Andrzej Marczuk
- e Department of Transporting and Agricultural Machinery , University of Life Sciences , Lublin , Poland
| | - Mariusz Gagoś
- a Department of Cell Biology , Maria Curie-Skłodowska University , Lublin , Poland
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16
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Del Pozo JL, Cantón E. Candidiasis asociada a biopelículas. Rev Iberoam Micol 2016; 33:176-83. [DOI: 10.1016/j.riam.2015.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 06/14/2015] [Accepted: 06/23/2015] [Indexed: 11/27/2022] Open
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Bhattacharjee P. Epidemiology and antifungal susceptibility of Candida species in a tertiary care hospital, Kolkata, India. Curr Med Mycol 2016; 2:20-27. [PMID: 28681016 PMCID: PMC5490301 DOI: 10.18869/acadpub.cmm.2.2.5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background and Purpose: The incidence of fungal infection as well as candidemia has increased significantly, contributing to morbidity and mortality in the developed countries. The alarming increase in infections with multidrug resistant bacteria is due to overuse of a broad spectrum antimicrobials, which leads to over growth of Candida spp.; thus, enhancing its opportunity to cause the disease. A shift has been observed in the relative frequency of each Candida spp. Antifungal agents available for the treatment of systemic and invasive candidiasis are restricted to polyenes, allylamines, azoles, and the recent echinocandin class of molecules. In the past few decades, the incidence of resistance to antifungal treatment of Candida spp. has increased rapidly, which is of serious concern for healthcare professionals. Studies on prevalence of infections and antifungal susceptibility testing can help with deciding on clinical strategies to manage this problem. Herein, we aimed to identify the epidemiology of Candida spp. among blood culture isolates and to investigate the susceptibility pattern of these species to antifungal agents. Materials and Methods: Candida spp. were isolated from blood cultures from 70 patients in a tertiary care hospital, Kolkata, India. The growth of Candida spp. on sabouraud dextrose agar was confirmed by Gram staining, where gram-positive budding fungal cells were observed. The species identification as well as antifungal susceptibility testing were performed with VITEK 2 compact automated system using VITEK-2 cards for identification of yeast and yeast-like organisms) ID-YST card). Antifungal susceptibility testing was carried out with VITEK 2 fungal susceptibility card (AST-YS07 kit). Results: Out of 70 samples, Candidaalbicans were isolated from 34 (%48.57) samples. The remaining 36 (%51.43) were non-albicans Candida ) NAC). Out of 34 C. Albicans, antifungal susceptiblity was detected in 28 isolates, all of which were sensitive to fluconazole (FLC .( Resistance to amphotericine B) AMP), flucytosine (5FC), voriconazole (VRC), and itraconazole (ITC) was observed in, %44.12 , %52.94 , %8.82 and %17.65 of the cases, respectively. For other Candida spp. (other than C. Albicans ,( antifungal susceptibility was evaluated for 36 isolates, among which resistance to AMP, FLC , 5FC, VRC , and ITC was found in, %30.56 , %61.11 , %33.33 , %19.44 and %38.89 cases, respectively. Conclusion: Species-level identification of Candida and their antifungal sensitivity testing should to be performed to achieve better clinical result and to select an appropriate and effective antifungal therapy. High resistance to antifungal agents is an alarming sign to the healthcare professionals.
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Affiliation(s)
- P Bhattacharjee
- NH-Rabindranath Tagore International Institute of Cardiac Sciences 124, E. M. Bypass, Mukundapur, Kolkata-700099, West Bengal, India
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Abstract
Fungal biofilms have become an increasingly important clinical problem. The widespread use of antibiotics, frequent use of indwelling medical devices, and a trend toward increased patient immunosuppression have resulted in a creation of opportunity for clinically important yeasts and molds to form biofilms. This review will discuss the diversity and importance of fungal biofilms in the context of clinical medicine, provide novel insights into the clinical management of fungal biofilm infection, present evidence why these structures are recalcitrant to antifungal therapy, and discuss how our knowledge and understanding may lead to novel therapeutic intervention.
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Evaluation of baicalein, chitosan and usnic acid effect on Candida parapsilosis and Candida krusei biofilm using a Cellavista device. J Microbiol Methods 2015; 118:106-12. [DOI: 10.1016/j.mimet.2015.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/04/2015] [Accepted: 09/05/2015] [Indexed: 11/21/2022]
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Chandra J, Mukherjee PK. Candida Biofilms: Development, Architecture, and Resistance. Microbiol Spectr 2015; 3:10.1128/microbiolspec.MB-0020-2015. [PMID: 26350306 PMCID: PMC4566167 DOI: 10.1128/microbiolspec.mb-0020-2015] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Indexed: 12/17/2022] Open
Abstract
Intravascular device-related infections are often associated with biofilms (microbial communities encased within a polysaccharide-rich extracellular matrix) formed by pathogens on the surfaces of these devices. Candida species are the most common fungi isolated from catheter-, denture-, and voice prosthesis-associated infections and also are commonly isolated from contact lens-related infections (e.g., fungal keratitis). These biofilms exhibit decreased susceptibility to most antimicrobial agents, which contributes to the persistence of infection. Recent technological advances have facilitated the development of novel approaches to investigate the formation of biofilms and identify specific markers for biofilms. These studies have provided extensive knowledge of the effect of different variables, including growth time, nutrients, and physiological conditions, on biofilm formation, morphology, and architecture. In this article, we will focus on fungal biofilms (mainly Candida biofilms) and provide an update on the development, architecture, and resistance mechanisms of biofilms.
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Affiliation(s)
- Jyotsna Chandra
- Center for Medical Mycology and Mycology Reference Laboratory, Department of Dermatology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH 44106
| | - Pranab K Mukherjee
- Center for Medical Mycology and Mycology Reference Laboratory, Department of Dermatology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH 44106
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Akbari F, Kjellerup BV. Elimination of Bloodstream Infections Associated with Candida albicans Biofilm in Intravascular Catheters. Pathogens 2015; 4:457-69. [PMID: 26131615 PMCID: PMC4584267 DOI: 10.3390/pathogens4030457] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 06/07/2015] [Accepted: 06/19/2015] [Indexed: 11/16/2022] Open
Abstract
Intravascular catheters are among the most commonly inserted medical devices and they are known to cause a large number of catheter related bloodstream infections (BSIs). Biofilms are associated with many chronic infections due to the aggregation of microorganisms. One of these organisms is the fungus Candida albicans. It has shown to be one of the leading causes of catheter-related BSIs. The presence of biofilm on intravascular catheters provide increased tolerance against antimicrobial treatments, thus alternative treatment strategies are sought. Traditionally, many strategies, such as application of combined antimicrobials, addition of antifungals, and removal of catheters, have been practiced, but they were not successful in eradicating BSIs. Since these fungal infections can result in significant morbidity, mortality, and increased healthcare cost, other promising preventive strategies, including antimicrobial lock therapy, chelating agents, alcohol, and biofilm disruptors, have been applied. In this review, current success and failure of these new approaches, and a comparison with the previous strategies are discussed in order to understand which preventative treatment is the most effective in controlling the catheter-related BSIs.
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Affiliation(s)
- Freshta Akbari
- Department of Biological Sciences, Goucher College, Baltimore, MD 21204, USA.
| | - Birthe Veno Kjellerup
- Department of Civil and Environmental Engineering, University of Maryland at College Park, College Park, MD 20742, USA.
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22
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Pahwa N, Kumar R, Nirkhiwale S, Bandi A. Species distribution and drug susceptibility of candida in clinical isolates from a tertiary care centre at Indore. Indian J Med Microbiol 2014; 32:44-8. [PMID: 24399387 DOI: 10.4103/0255-0857.124300] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The incidence of fungal infections has increased significantly, contributing to morbidity andmortality. This is caused by an alarming increase in infections with multi-drug resistant bacteria leading to overuse of broad-spectrum antimicrobials, which lead to overgrowth of Candida, thus enhancing its opportunity to cause disease. Candida are major human fungal pathogens that cause both mucosal and deep tissue infections. OBJECTIVE The aim of our study was to identify the distribution of Candida species among clinical isolates and their sensitivity pattern for common antifungal drugs. MATERIALS AND METHODS Two hundred and thirty-sevendifferent clinical isolates of Candida were collected from patients visiting to a tertiary care centre of Indore from 2010 to 2012. Identification of Candida species as well antifungal sensitivity testing was performed with Vitek2 Compact (Biomerieux France) using ID-YST Kits. Antifungal susceptibility testing was performed with AST YS01 KitsonVitek2 Compact. RESULTS We found that the non-albicans Candida were more prevalent than Candida albicans in paediatric (<3 year) and older (>60 year) patients than other age group (4-18, 19-60 years) patients and also in intensive care unit (ICU) patients as compared to out patient department (OPD) patients. Resistance rates for amphotericin B, fluconazole, flucytosine, itraconazole, and voriconazolewere 2.9%, 5.9%, 0.0%, 4.2% and 2.5%%, respectively. All the strains of C. krusei were found resistant to fluconazole with intermediate sensitivity to flucytosine. CONCLUSION Species-level identification of Candidaand their antifungal sensitivity testing should be performed to achieve better clinical results.
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Affiliation(s)
| | | | - S Nirkhiwale
- Department of Laboratory Medicine, Greater Kailash Hospital, Indore, Madhya Pradesh, India
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23
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Taff HT, Mitchell KF, Edward JA, Andes DR. Mechanisms of Candida biofilm drug resistance. Future Microbiol 2014; 8:1325-37. [PMID: 24059922 DOI: 10.2217/fmb.13.101] [Citation(s) in RCA: 262] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Candida commonly adheres to implanted medical devices, growing as a resilient biofilm capable of withstanding extraordinarily high antifungal concentrations. As currently available antifungals have minimal activity against biofilms, new drugs to treat these recalcitrant infections are urgently needed. Recent investigations have begun to shed light on the mechanisms behind the profound resistance associated with the biofilm mode of growth. This resistance appears to be multifactorial, involving both mechanisms similar to conventional, planktonic antifungal resistance, such as increased efflux pump activity, as well as mechanisms specific to the biofilm lifestyle. A unique biofilm property is the production of an extracellular matrix. Two components of this material, β-glucan and extracellular DNA, promote biofilm resistance to multiple antifungals. Biofilm formation also engages several stress response pathways that impair the activity of azole drugs. Resistance within a biofilm is often heterogeneous, with the development of a subpopulation of resistant persister cells. In this article we review the molecular mechanisms underlying Candida biofilm antifungal resistance and their relative contributions during various growth phases.
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Affiliation(s)
- Heather T Taff
- Departments of Medicine & Medical Microbiology & Immunology, University of Wisconsin, Madison, Wisconsin, USA
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Kabir MA, Hussain MA, Ahmad Z. Candida albicans: A Model Organism for Studying Fungal Pathogens. ISRN MICROBIOLOGY 2012; 2012:538694. [PMID: 23762753 PMCID: PMC3671685 DOI: 10.5402/2012/538694] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 08/30/2012] [Indexed: 01/12/2023]
Abstract
Candida albicans is an opportunistic human fungal pathogen that causes candidiasis. As healthcare has been improved worldwide, the number of immunocompromised patients has been increased to a greater extent and they are highly susceptible to various pathogenic microbes and C. albicans has been prominent among the fungal pathogens. The complete genome sequence of this pathogen is now available and has been extremely useful for the identification of repertoire of genes present in this pathogen. The major challenge is now to assign the functions to these genes of which 13% are specific to C. albicans. Due to its close relationship with yeast Saccharomyces cerevisiae, an edge over other fungal pathogens because most of the technologies can be directly transferred to C. albicans from S. cerevisiae and it is amenable to mutation, gene disruption, and transformation. The last two decades have witnessed enormous amount of research activities on this pathogen that leads to the understanding of host-parasite interaction, infections, and disease propagation. Clearly, C. albicans has emerged as a model organism for studying fungal pathogens along with other two fungi Aspergillus fumigatus and Cryptococcus neoformans. Understanding its complete life style of C. albicans will undoubtedly be useful for developing potential antifungal drugs and tackling Candida infections. This will also shed light on the functioning of other fungal pathogens.
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Affiliation(s)
- M Anaul Kabir
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut 673601, Kerala, India
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25
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Abstract
Candida species have two distinct lifestyles: planktonic, and surface-attached communities called biofilms. Mature C. albicans biofilms show a complex three-dimensional architecture with extensive spatial heterogeneity, and consist of a dense network of yeast, hyphae, and pseudohyphae encased within a matrix of exopolymeric material. Several key processes are likely to play vital roles at the different stages of biofilm development, such as cell-substrate and cell-cell adherence, hyphal development, and quorum sensing. Biofilm formation is a survival strategy, since biofilm yeasts are more resistant to antifungals and environmental stress. Antifungal resistance is a multifactorial process that includes multidrug efflux pumps, target proteins of the ergosterol biosynthetic pathway. Most studies agree in presenting azoles as agents with poor activity against Candida spp. biofilms. However, recent studies have demonstrated that echinocandins and amphotericin B exhibit remarkable activity against C. albicans and Candida non-albicans biofilms. The association of Candida species with biofilm formation increases the therapeutic complexity of foreign body-related yeast infections. The traditional approach to the management of these infections has been to explant the affected device. There is a strong medical but also economical motivation for the development of novel anti-fungal biofilm strategies due to the constantly increasing resistance of Candida biofilms to conventional antifungals, and the high mortality caused by related infections. A better description of the extent and role of yeast in biofilms may be critical for developing novel therapeutic strategies in the clinical setting.
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Abstract
Fungal biofilm infections have become increasingly recognised as a significant clinical problem. One of the major reasons behind this is the impact that these have upon treatment, as antifungal therapy often fails and surgical intervention is required. This places a large financial burden on health care providers. This paper aims to illustrate the importance of fungal biofilms, particularly Candida albicans, and discusses some of the key fungal biofilm resistance mechanisms that include, extracellular matrix (ECM), efflux pump activity, persisters, cell density, overexpression of drug targets, stress responses, and the general physiology of the cell. The paper demonstrates the multifaceted nature of fungal biofilm resistance, which encompasses some of the newest data and ideas in the field.
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Agarwal S, Manchanda V, Verma N, Bhalla P. Yeast identification in routine clinical microbiology laboratory and its clinical relevance. Indian J Med Microbiol 2011; 29:172-7. [PMID: 21654115 DOI: 10.4103/0255-0857.81794] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Rapid identification of yeast infections is helpful in prompt appropriate antifungal therapy. In the present study, the usefulness of chromogenic medium, slide culture technique and Vitek2 Compact (V2C) has been analysed. A total of 173 clinical isolates of yeast species were included in the study. An algorithm to identify such isolates in routine clinical microbiology laboratory was prepared and followed. Chromogenic medium was able to identify Candida albicans, C. tropicalis, C. krusei, C. parapsilosis and Trichosporon asahii. Chromogenic medium was also helpful in identifying "multi-species" yeast infections. The medium was unable to provide presumptive identification of C. pelliculosa, C. utilis, C. rugosa, C. glabrata and C. hemulonii. Vitek 2 compact (V2C) differentiated all pseudohypae non-producing yeast species. The algorithm followed was helpful in timely presumptive identification and final diagnosis of yeast infections, including multi-species yeast infections.
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Affiliation(s)
- S Agarwal
- Clinical Microbiology and Infectious Diseases, Chacha Nehru Bal Chikitsalaya, New Delhi 110 031, India.
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28
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Pérez A, Ramage G, Blanes R, Murgui A, Casanova M, Martínez JP. Some biological features of Candida albicans mutants for genes coding fungal proteins containing the CFEM domain. FEMS Yeast Res 2011; 11:273-84. [PMID: 21205162 DOI: 10.1111/j.1567-1364.2010.00714.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Several biological features of Candida albicans genes (PGA10, RBT5 and CSA1) coding for putative polypeptide species belonging to a subset of fungal proteins containing an eight-cysteine domain referred as common in several fungal extracellular membrane (CFEM) are described. The deletion of these genes resulted in a cascade of pleiotropic effects. Thus, mutant strains exhibited higher cell surface hydrophobicity levels and an increased ability to bind to inert or biological substrates. Confocal scanning laser microscopy using concanavalin A-Alexafluor 488 (which binds to mannose and glucose residues) and FUN-1 (a cytoplasmic fluorescent probe for cell viability) dyes showed that mutant strains formed thinner and more fragile biofilms. These apparently contained lower quantities of extracellular matrix material and less metabolically active cells than their parental strain counterpart, although the relative percentage of mycelial forms was similar in all cases. The cell surface of C. albicans strains harbouring deletions for genes coding CFEM-domain proteins appeared to be severely altered according to atomic force microscopy observations. Assessment of the relative gene expression within individual C. albicans cells revealed that CFEM-coding genes were upregulated in mycelium, although these genes were shown not to affect virulence in animal models. Overall, this study has demonstrated that CFEM domain protein-encoding genes are pleiotropic, influencing cell surface characteristics and biofilm formation.
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Affiliation(s)
- Ana Pérez
- Departamento de Microbiología y Ecología, Facultad de Farmacia, Universitat de València, Burjasot, Valencia, Spain
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Transcriptional response of Candida albicans biofilms following exposure to 2-amino-nonyl-6-methoxyl-tetralin muriate. Acta Pharmacol Sin 2010; 31:616-28. [PMID: 20383169 DOI: 10.1038/aps.2010.33] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
AIM To identify changes in the gene expression profile of Candida albicans (C albicans) biofilms following exposed to 2-amino-nonyl-6-methoxyl-tetralin muriate(10b) and clarify the mechanism of 10b against C albicans biofilms. METHODS Anti-biofilm activity of 10b was assessed by tetrazolium (XTT) reduction assay and the action mechanism against biofilms was investigated by cDNA microarray analysis and real-time RT-PCR assay. RESULTS Ten differentially expressed genes were directly linked to biofilm formation and filamentous or hyphal growth (eg, NRG1, ECE1 and CSA1). Decreased gene expression was involved in glycolysis (eg, HXK2 and PFK1) and antioxidant defense (eg, SOD5), while increased gene expression was associated with enzymes that specifically hydrolyzed beta-1,3 glucan (XOG1), and with lipid, fatty acid and sterol metabolism (eg, SLD1, ERG6 and ERG2). Functional analysis indicated that addition of anti-oxidant ascorbic acid reduced inhibitory efficiency of 10b on mature biofilm. CONCLUSION Inhibition of 10b on biofilm formation possibly depends on impairing the ability of C albicans to change its morphology via altering the expression of biofilm formation genes. Mitochondrial aerobic respiration shift and endogenous ROS augmentation might be a major contribution to reduce mature biofilm metabolic activity. The data may be useful for the development of new strategies to reduce the incidence of device-associated infections.
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Pseudomonas aeruginosa secreted factors impair biofilm development in Candida albicans. Microbiology (Reading) 2010; 156:1476-1486. [DOI: 10.1099/mic.0.037549-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Signal-mediated interactions between the human opportunistic pathogens Pseudomonas aeruginosa and Candida albicans affect virulence traits in both organisms. Phenotypic studies revealed that bacterial supernatant from four P. aeruginosa strains strongly reduced the ability of C. albicans to form biofilms on silicone. This was largely a consequence of inhibition of biofilm maturation, a phenomenon also observed with supernatant prepared from non-clinical bacterial species. The effects of supernatant on biofilm formation were not mediated via interference with the yeast–hyphal morphological switch and occurred regardless of the level of homoserine lactone (HSL) produced, indicating that the effect is HSL-independent. A transcriptome analysis to dissect the effects of the P. aeruginosa supernatants on gene expression in the early stages of C. albicans biofilm formation identified 238 genes that exhibited reproducible changes in expression in response to all four supernatants. In particular, there was a strong increase in the expression of genes related to drug or toxin efflux and a decrease in expression of genes associated with adhesion and biofilm formation. Furthermore, expression of YWP1, which encodes a protein known to inhibit biofilm formation, was significantly increased. Biofilm formation is a key aspect of C. albicans infections, therefore the capacity of P. aeruginosa to antagonize this has clear biomedical implications.
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Cai Y, Yu XH, Wang R, An MM, Liang BB. Effects of iron depletion on antimicrobial activities against planktonic and biofilm Pseudomonas aeruginosa. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.61.09.0017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Objectives
Iron plays an important role in the development of Pseudomonas aeruginosa biofilm. Here we evaluated effects of iron depletion on the antimicrobial activity of ceftazidime, tobramycin and ciprofloxacin against planktonic and biofilm Pseudomonas aeruginosa.
Methods
We tested the sensitivities of wild-type PAO1, type-IV pilus mutant PAO-ΔpilHIJK and the quorum-sensing mutant PAO-JP2 P. aeruginosa planktonic cultures and biofilms to antibiotics under iron-depleted conditions.
Key findings
In planktonic bacteria, the minimum concentration that inhibited visible growth (MIC) of ciprofloxacin was increased slightly in an iron-depleted environment in all three strains, whereas the MIC of tobramycin was similar in iron-depleted and control environments. The MIC of ceftazidime increased in the PAO-JP2 strain when iron was depleted. Tobramycin achieved the best bactericidal effect in biofilms. Viable counts were reduced by one log under iron-depleted conditions in all three strains when tobramycin reached 4 MIC and when ceftazidime and ciprofloxacin reached 8 MIC.
Conclusions
This study suggests that once the biofilm is formed, iron depletion may only slightly promote the bactericidal effect of antibiotics on PAO1, PAO-ΔpilHIJK and PAO-JP2. Although these changes were relatively small, iron as one of the environmental factors should not be ignored when evaluating bactericidal effect of antibiotics. The combination of an iron chelator and antibiotics may have therapeutic value under certain bacterial growth conditions.
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Affiliation(s)
- Yun Cai
- Department of Clinical Pharmacology, the PLA General Hospital, Beijing, PR China
| | - Xu-Hong Yu
- Department of Clinical Pharmacology, the PLA General Hospital, Beijing, PR China
| | - Rui Wang
- Department of Clinical Pharmacology, the PLA General Hospital, Beijing, PR China
| | - Mao-Mao An
- Department of Clinical Pharmacology, the PLA General Hospital, Beijing, PR China
| | - Bei-Bei Liang
- Department of Clinical Pharmacology, the PLA General Hospital, Beijing, PR China
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Ramage G, Mowat E, Jones B, Williams C, Lopez-Ribot J. Our current understanding of fungal biofilms. Crit Rev Microbiol 2010; 35:340-55. [PMID: 19863383 DOI: 10.3109/10408410903241436] [Citation(s) in RCA: 324] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Fungal biofilms are an escalating clinical problem associated with significant rates of mortality. Candida albicans is the most notorious of all fungal biofilm formers. However, non-Candida species, yeasts such as Cryptococcus neoformans, and filamentous moulds such as Aspergillus fumigatus, have been shown to be implicated in biofilm-associated infections. Fungal biofilms have distinct developmental phases, including adhesion, colonisation, maturation and dispersal, which are governed by complex molecular events. Recalcitrance to antifungal therapy remains the greatest threat to patients with fungal biofilms. This review discusses our current understanding of the basic biology and clinical implications associated with fungal biofilms.
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Affiliation(s)
- Gordon Ramage
- Section of Infection and Immunity, Glasgow Dental School and Hospital, Faculty of Medicine, University of Glasgow, UK.
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Abstract
A filter disk assay is described, which measures the penetration of antifungal agents through Candida biofilms. The technique involves forming a colony biofilm on a polycarbonate membrane filter, and capping it with a second, smaller membrane filter followed by a wetted paper disk of the type used in zone-of-inhibition assays. The entire assembly is transferred to agar medium containing the antifungal agent of interest. During subsequent incubation, the drug diffuses out of the agar and through the biofilm 'sandwich' to the moistened paper disk. The drug concentration in the disk can be determined by measuring the zone of growth inhibition that it produces on medium seeded with an indicator strain of Candida albicans in standard bioassays. Additional procedures are outlined for determining the viabilities of drug-treated biofilms and for examining biofilm morphology by scanning electron microscopy.
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Sellam A, Al-Niemi T, McInnerney K, Brumfield S, Nantel A, Suci PA. A Candida albicans early stage biofilm detachment event in rich medium. BMC Microbiol 2009; 9:25. [PMID: 19187560 PMCID: PMC2647545 DOI: 10.1186/1471-2180-9-25] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 02/02/2009] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Dispersal from Candida albicans biofilms that colonize catheters is implicated as a primary factor in the link between contaminated catheters and life threatening blood stream infections (BSI). Appropriate in vitro C. albicans biofilm models are needed to probe factors that induce detachment events. RESULTS Using a flow through system to culture C. albicans biofilms we characterized a detachment process which culminates in dissociation of an entire early stage biofilm from a silicone elastomer surface. We analyzed the transcriptome response at time points that bracketed an abrupt transition in which a strong adhesive association with the surface is weakened in the initial stages of the process, and also compared batch and biofilm cultures at relevant time points. K means analysis of the time course array data revealed categories of genes with similar patterns of expression that were associated with adhesion, biofilm formation and glycoprotein biosynthesis. Compared to batch cultures the biofilm showed a pattern of expression of metabolic genes that was similar to the C. albicans response to hypoxia. However, the loss of strong adhesion was not obviously influenced by either the availability of oxygen in the medium or at the silicone elastomer surface. The detachment phenotype of mutant strains in which selected genes were either deleted or overexpressed was characterized. The microarray data indicated that changes associated with the detachment process were complex and, consistent with this assessment, we were unable to demonstrate that transcriptional regulation of any single gene was essential for loss of the strong adhesive association. CONCLUSION The massive dispersal of the early stage biofilm from a biomaterial surface that we observed is not orchestrated at the level of transcriptional regulation in an obvious manner, or is only regulated at this level by a small subpopulation of cells that mediate adhesion to the surface.
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Affiliation(s)
- Adnane Sellam
- Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada.
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Pierce CG, Uppuluri P, Tristan AR, Wormley FL, Mowat E, Ramage G, Lopez-Ribot JL. A simple and reproducible 96-well plate-based method for the formation of fungal biofilms and its application to antifungal susceptibility testing. Nat Protoc 2008; 3:1494-500. [PMID: 18772877 DOI: 10.1038/nport.2008.141] [Citation(s) in RCA: 344] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The incidence of fungal infections has increased significantly over the past decades. Very often these infections are associated with biofilm formation on implanted biomaterials and/or host surfaces. This has important clinical implications, as fungal biofilms display properties that are dramatically different from planktonic (free-living) populations, including increased resistance to antifungal agents. Here we describe a rapid and highly reproducible 96-well microtiter-based method for the formation of fungal biofilms, which is easily adaptable for antifungal susceptibility testing. This model is based on the ability of metabolically active sessile cells to reduce a tetrazolium salt (2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide) to water-soluble orange formazan compounds, the intensity of which can then be determined using a microtiter-plate reader. The entire procedure takes approximately 2 d to complete. This technique simplifies biofilm formation and quantification, making it more reliable and comparable among different laboratories, a necessary step toward the standardization of antifungal susceptibility testing of biofilms.
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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, Texas 78249, USA
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A simple and reproducible 96-well plate-based method for the formation of fungal biofilms and its application to antifungal susceptibility testing. Nat Protoc 2008. [DOI: 10.1038/nprot.2008.141] [Citation(s) in RCA: 571] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cell density and cell aging as factors modulating antifungal resistance of Candida albicans biofilms. Antimicrob Agents Chemother 2008; 52:3259-66. [PMID: 18625775 DOI: 10.1128/aac.00541-08] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biofilm formation is a major virulence attribute of Candida pathogenicity which contributes to higher antifungal resistance. We investigated the roles of cell density and cellular aging on the relative antifungal susceptibility of planktonic, biofilm, and biofilm-derived planktonic modes of Candida. A reference and a wild-type strain of Candida albicans were used to evaluate the MICs of caspofungin (CAS), amphotericin B (AMB), nystatin (NYT), ketoconazole (KTC), and flucytosine (5FC). Standard, NCCLS, and European Committee on Antibiotic Susceptibility Testing methods were used for planktonic MIC determination. Candida biofilms were then developed on polystyrene wells, and MICs were determined with a standard 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide assay. Subsequently, antifungal susceptibility testing was performed for greater inoculum concentrations and 24- and 48-h-old cultures of planktonic Candida. Furthermore, Candida biofilm-derived planktonic cells (BDPC) were also subjected to antifungal susceptibility testing. The MICs for both C. albicans strains in the planktonic mode were low, although on increasing the inoculum concentration (up to 1 x 10(8) cells/ml), a variable MIC was noted. On the contrary, for Candida biofilms, the MICs of antifungals were 15- to >1,000-fold higher. Interestingly, the MICs for BDPC were lower and were similar to those for planktonic-mode cells, particularly those of CAS and AMB. Our data indicate that higher antifungal resistance of Candida biofilms is an intrinsic feature possibly related to the biofilm architecture rather than cellular density or cellular aging.
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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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Perumal P, Mekala S, Chaffin WL. Role for cell density in antifungal drug resistance in Candida albicans biofilms. Antimicrob Agents Chemother 2007; 51:2454-63. [PMID: 17502416 PMCID: PMC1913227 DOI: 10.1128/aac.01237-06] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biofilms of Candida albicans are less susceptible to many antifungal drugs than are planktonic yeast cells. We investigated the contribution of cell density to biofilm phenotypic resistance. Planktonic yeast cells in RPMI 1640 were susceptible to azole-class drugs, amphotericin B, and caspofungin at 1 x 10(3) cells/ml (standard conditions) using the XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide sodium salt] assay. As reported by others, as the cell concentration increased to 1 x 10(8) cells/ml, resistance was observed with 10- to 20-fold-greater MICs. Biofilms that formed in microtiter plate wells, like high-density planktonic organisms, were resistant to drugs. When biofilms were resuspended before testing, phenotypic resistance remained, but organisms, when diluted to 1 x 10(3) cells/ml, were susceptible. Drug-containing medium recovered from high-cell-density tests inhibited low-cell-density organisms. A fluconazole-resistant strain showed greater resistance at high planktonic cell density, in biofilm, and in resuspended biofilm than did low-density planktonic or biofilm organisms. A strain lacking drug efflux pumps CDR1, CDR2, and MDR1, while susceptible at a low azole concentration, was resistant at high cell density and in biofilm. A strain lacking CHK1 that fails to respond to the quorum-sensing molecule farnesol had the same response as did the wild type. FK506, reported to abrogate tolerance to azole drugs at low cell density, had no effect on tolerance at high cell density and in biofilm. These observations suggested that cell density has a role in the phenotypic resistance of biofilm, that neither the drug efflux pumps tested nor quorum sensing through Chk1p contributes to resistance, and that azole drug tolerance at high cell density differs mechanistically from tolerance at low cell density.
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Affiliation(s)
- Palani Perumal
- Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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41
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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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42
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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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43
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Ramage G, Martínez JP, López-Ribot JL. Candida biofilms on implanted biomaterials: a clinically significant problem. FEMS Yeast Res 2006; 6:979-86. [PMID: 17042747 DOI: 10.1111/j.1567-1364.2006.00117.x] [Citation(s) in RCA: 395] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
In recent years there has been an increasing appreciation that microbial biofilms are ubiquitous, which has resulted in a number of studies on infectious diseases from a biofilm perspective. Biofilms are defined as structured microbial communities that are attached to a surface and encased in a matrix of exopolymeric material. A wide range of biomaterials used in clinical practice have been shown to support colonization and biofilm formation by Candida spp., and the increase in Candida infections in the last decades has almost paralleled the increase and widespread use of a broad range of medical implant devices, mainly in populations with impaired host defenses. Formation of Candida biofilms has important clinical repercussions because of their increased resistance to antifungal therapy and the ability of cells within biofilms to withstand host immune defenses. Further recognition and understanding of the role of Candida biofilms in human infection should help in the clinical management of these recalcitrant infections.
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Affiliation(s)
- Gordon Ramage
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, UK
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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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Al-Fattani MA, Douglas LJ. Biofilm matrix of Candida albicans and Candida tropicalis: chemical composition and role in drug resistance. J Med Microbiol 2006; 55:999-1008. [PMID: 16849719 DOI: 10.1099/jmm.0.46569-0] [Citation(s) in RCA: 360] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
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 easily detached from plastic surfaces by treatment with the enzyme lyticase (β-1,3-glucanase) than were those of C. tropicalis. Biofilms of C. albicans were also partially detached by treatment with proteinase K, chitinase, DNase I, or β-N-acetylglucosaminidase, whereas C. tropicalis biofilms were only affected by lipase type VII or chitinase. To investigate a possible role for the matrix in biofilm resistance to antifungal agents, biofilms of C. albicans were grown under conditions of continuous flow in a modified Robbins device (MRD). These biofilms produced more matrix material than those grown statically, and were significantly more resistant to amphotericin B. Biofilms of C. tropicalis synthesized large amounts of matrix material even when grown statically, and such biofilms were completely resistant to both amphotericin B and fluconazole. Mixed-species biofilms of C. albicans and a slime-producing strain of Staphylococcus epidermidis (RP62A), when grown statically or in the MRD, were also completely resistant to amphotericin B and fluconazole. Mixed-species biofilms of C. albicans and a slime-negative mutant of S. epidermidis (M7), on the other hand, were completely drug resistant only when grown under flow conditions. These results demonstrate that the matrix can make a significant contribution to drug resistance in Candida biofilms, especially under conditions similar to those found in catheter infections in vivo, and that the composition of the matrix material is an important determinant in resistance.
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Affiliation(s)
- Mohammed A Al-Fattani
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - L Julia Douglas
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK
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Nett J, Andes D. Candida albicans biofilm development, modeling a host-pathogen interaction. Curr Opin Microbiol 2006; 9:340-5. [PMID: 16815078 DOI: 10.1016/j.mib.2006.06.007] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Accepted: 06/20/2006] [Indexed: 10/24/2022]
Abstract
Medical device-associated infections involve the attachment of cells to a surface, production of an extracellular matrix and development of a mature biofilm. Many Candida albicans disease states involve biofilm growth. These infections have great impact on public health because organisms in biofilms exhibit dramatically reduced susceptibility to antifungal therapy. Progression to a mature biofilm is dependent on cell adhesion, extracellular matrix production and the yeast-to-hyphae transition. Numerous in vitro biofilm model systems have been successfully used to examine biofilm architecture, development, cell phenotypes and drug resistance. Although these studies have included a number of experimental variables to mimic infections in patients, it is difficult to accurately account for the multitude of host and infection-site variables that are probably important in humans. Recent studies have begun to explore C. albicans biofilms using animal biofilm infection models in order to more completely reflect the complexity of this host-fungal interaction.
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Affiliation(s)
- Jeniel Nett
- University of Wisconsin, Department of Medicine and Medical Microbiology and Immunology, Madison, WI 53792, USA
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Parahitiyawa NB, Samaranayake YH, Samaranayake LP, Ye J, Tsang PWK, Cheung BPK, Yau JYY, Yeung SKW. Interspecies variation in Candida biofilm formation studied using the Calgary biofilm device. APMIS 2006; 114:298-306. [PMID: 16689830 DOI: 10.1111/j.1600-0463.2006.apm_394.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An in vitro assay to study multiple Candida biofilms, in parallel, has been carried out using the Calgary biofilm device (CBD). We here report: i) standardization of the CBD for Candida albicans biofilm formation, ii) kinetics of C. albicans biofilm formation, iii) biofilm formation by five Candida species, and iv) effect of dietary carbohydrates on biofilm formation. The biofilm metabolic activity on all CBD pegs was similar (p=0.6693) and C. albicans biofilm formation revealed slow growth up to 36 h and significantly higher growth up to 48 h (p<0.001). Significant differences in total biofilm metabolic activity were seen for glucose, fructose and lactose grown C. albicans compared with sucrose and maltose grown yeasts. Candida krusei developed the largest biofilm mass (p<0.05) relative to C. albicans, C. glabrata, C. dubliniensis and C. tropicalis. Scanning electron microscopy revealed that C. krusei produced a thick multilayered biofilm of pseudohyphal forms embedded within the polymer matrix, whereas C. albicans, C. dubliniensis and C. tropicalis biofilms consisted of clusters or chains of cells with sparse extracellular matrix material. We conclude that CBD is a useful, simple, low cost miniature device for parallel study of Candida biofilms and factors modulating this phenomenon.
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Affiliation(s)
- N B Parahitiyawa
- Oral Bio-sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
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Abstract
Oral candidiasis (OC) is the most common mucosal manifestation of HIV infection. This workshop examined OC and other mycoses associated with HIV infection. Historically, blood CD4 cell numbers were the primary prognosticator for the development of OC. However, a study that statistically evaluated the predictive role of HIV viral load vs. CD4 cell counts revealed viral load to be a stronger predictor for OC. The role of biofilms and antifungal resistance in recalcitrant OC is unclear at present. In general, micro-organisms including yeasts in biofilms are more resistant to antifungals than their planktonic counterparts. When the remaining organisms are eliminated, the few resistant organisms may not be problematic, because they are present in low numbers. Unusual exotic mycoses in HIV-infected patients are more common in patients from the developing than the developed world. These infections may be recurrent and recalcitrant to therapy, be present in multiple and uncommon sites, increase with the progression of HIV disease, and may play a role similar to that of the more common mycoses. Typing and subtyping of yeasts are probably not critical to the clinical management of candidiasis caused by Candida albicans and non-albicans strains, including C. dubliniensis, because it is responsive to antifungal therapy. C. glabrata is probably the only exception. The presence of oral thrush in infants younger than 6 months of age is associated with an increased post-natal transmission risk of HIV infection. Thus, perinatal retroviral therapy should be combined with the treatment of oral thrush to prevent the post-natal acquisition of HIV.
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Affiliation(s)
- M M Coogan
- Division of Oral Microbiology, School of Dentistry, University of the Witwatersrand, Private Bag X6, Wits 2050, Johannesburg, South Africa.
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Vediyappan G, Chaffin WL. Non-glucan attached proteins of Candida albicans biofilm formed on various surfaces. Mycopathologia 2006; 161:3-10. [PMID: 16389478 PMCID: PMC4957702 DOI: 10.1007/s11046-005-0167-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Accepted: 08/31/2005] [Indexed: 10/25/2022]
Abstract
Non-glucan attached proteins of the cell surface and extracellular matrix of Candida albicans biofilms formed on two catheter surfaces and denture acrylic were examined. The SDS-PAGE protein profiles of these proteins compared with that obtained from planktonic yeast cells and germ tubes were generally similar. This observation suggested that this class of biofilm surface proteins is not composed of a unique set of extracellular proteins or that one or a few proteins dominate the non-glucan attached proteins of biofilm. However, differences were observed in the proteins obtained from biofilm formed on one catheter surface and two proteins, Grp2p and ORF19.822p, identified by mass spectrometry following two-dimensional separation. These proteins have previously been associated with drug resistance and their presence or abundance appeared to be influenced by the surface on which the biofilm was formed.
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Affiliation(s)
- Govindsamy Vediyappan
- Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, USA
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50
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Abstract
Candida albicans, an opportunistic fungal pathogen, causes a wide variety of human diseases such as oral thrush and disseminated candidiasis. Many aspects of C. albicans physiology have been studied during liquid growth, but in its natural environment, the gastrointestinal tract of a mammalian host, the organism associates with surfaces. Growth on a surface triggers several behaviors, such as biofilm formation, invasion, and thigmotropism, that are important for infection. Recent discoveries have identified factors that regulate these behaviors and revealed the importance of these behaviors for pathogenesis.
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Affiliation(s)
- Carol A Kumamoto
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts 02111, USA.
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