Pathogens and Disease ISSN 2049-632X
EDITORIAL
Microbial biofilms – the coming of age of a research field DOI: 10.1111/2049-632X.12169
After successful meetings in Rome (2009) and Copenhagen (2011), the Biofilm Study Group of the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) (ESGB) organized the third EuroBiofilms meeting in Ghent (Belgium), from September 9 to September 12, 2013. With close to 300 participants coming from 30 different countries and more than 200 submitted abstracts, the meeting was very successful. It is clear that the field of microbial biofilms has come a long way since the early studies on biofilms (in the 1920s and 1930s, see the historical overview written by Niels Hoiby in this issue; Hoiby, 2014). The field has benefited dramatically from advances in our understanding of the molecular biology of microorganisms as well as from technological advances within microscopy techniques and methods for culture-independent investigation of microbial communities. While simple in vitro model systems are still very valuable to study fundamental aspects of the social behavior of microorganisms, we are gradually developing the capabilities of studying microbial biofilms under in vivo conditions. Results from these in vivo studies clearly indicate that the structure of many in vivo biofilms is very different from what is typically seen in in vitro biofilms and the use of in vivo models allows researchers to dissect the interplay between the host immune response and the microbial biofilm (Bjarnsholt et al., 2013). In addition, there is growing interest in and need for studying multispecies biofilms, both in in vitro and in vivo model systems (Burmølle et al., 2014). Particularly interesting in this regard are studies focusing on interactions between fungi (e.g. Candida albicans) and bacteria (e.g. Streptococcus mutans, Staphylococcus aureus, and S. epidermidis) (Peters et al., 2012; Beaussart et al., 2013; Metwalli et al., 2013). Despite considerable progress in this area over the last decade, much still remains to be learned about resistance, tolerance, and persistence in microbial biofilms. Resistance, tolerance, and persistence all contribute to the frequent failure of antimicrobial therapy directed against biofilm-related infections. While a picture starts to emerge where protection against oxidative stress, expression of efflux pumps, and protection provided by matrix polysaccharides all contribute to the biofilm-specific phenotype (Van Acker et al., 2014), it is still not completely clear how these mechanisms are regulated in different bacteria and fungi. In addition, there is growing evidence that the outcome of antimicrobial therapy is also determined by the composition of the biofilm and the interactions between different organisms in a multispecies biofilms, and it is often observed that the simultaneous presence and interaction of different microorganisms in an infection
can lead to failure of antimicrobial therapy (for example Perez et al., 2014). An important aspect of future biofilm research is the need for standardization, and in this regard, two European initiatives stand out. First, the Biofomics platform was created for the systematic and large-scale compilation, processing, and analysis of biofilm data from high-throughput experiments. This ‘biofilm database’ can be accessed at http://biofomics.org/ and is accompanied by the Minimum Information About a Biofilm Experiment (MIABiE) initiative. MIABiE presents guidelines about the data that need to be made available in order for the procedure and results of a particular experiment to be easily and unequivocally interpreted and – equally important – reproduced (Lourencßo et al., 2014). Secondly, within the framework of the ESGB, Niels Hoiby is coordinating an initiative to develop clinical guidelines for the diagnosis and treatment of biofilm infections. Both initiatives were presented at the Eurobiofilms 2013 meeting in Ghent, and useful input from the audience was obtained. The groups behind both initiatives will remain in touch with the biofilm community to constantly improve and update the guidelines and recommendations. This thematic issue contains 27 papers (including seven MiniReviews) that highlight some of the trends in biofilm research, as presented at Eurobiofilms 2013. We would like to take the opportunity to thank our sponsors (the Federation of European Biochemical Societies, the Research Foundation – Flanders, the Belgian Science Policy Office, the Faculty of Pharmaceutical Sciences of Ghent University and VIB), ESCMID (for providing attendance grants to 14 participants), and all participants. Finally, we look forward to seeing you at the fourth Eurobiofilms meeting that will be hosted by Dr Veronika Hola in Brno (Czech Republic) in 2015.
Tom Coenye Guest Editor Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium ESCMID Biofilm Study Group E-mail: [email protected] Patrick Van Dijck Guest Editor Department of Molecular Microbiology, VIB, and Laboratory of Molecular Cell Biology, KU Leuven, Leuven, Belgium E-mail: [email protected]
Pathogens and Disease (2014), 70, 203–204, © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved
203
Editorial
Thomas Bjarnsholt Guest Editor Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health Sciences, and Department for Clinical Microbiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark ESCMID Biofilm Study Group E-mail: [email protected] Ake Forsberg Issue Editor Department of Molecular Biology, Umea University, Umea, Sweden E-mail: [email protected] References Beaussart A, Herman P, El-Kirat-Chatel S, Lipke P, Kucharikova S, ^ne Y (2013) Single-cell force spectroscopy of Van Dijck P & Dufre the medically-important Staphylococcus epidermidis-Candida albicans interaction. Nanoscale 5: 10894–10900. Bjarnsholt T, Alhede M, Alhede M, Eickhardt-Sørensen SR, Moser €hl M, Jensen PØ & Høiby N (2013) The in vivo biofilm. C, Ku Trends Microbiol 21: 466–474.
204
Burmølle M, Ren D, Bjarnsholt T & Sørensen SJ (2014) Interactions in multispecies biofilms: do they actually matter? Trends Microbiol 22: 84–91. Hoiby N. (2014) A personal history of research on microbial biofilms and biofilm infections. Pathog Dis 70: 205–211. Lourencßo A, Coenye T, Goeres D et al. (2014) Minimum information about a biofilm experiment (MIABiE): standards for reporting experiments and data on sessile microbial communities living at interfaces. Pathog Dis 70: 238–244. Metwalli KH, Khan SA, Krom BP & Jabra-Rizk MA (2013) Streptococcus mutans, Candida albicans, and the human mouth: a sticky situation. PLoS Pathog 9: e1003616. Perez AC, Pang B, King LB, Tan L, Murrah KA, Reimche JL, Wren JT, Richardson SH, Ghandi U & Swords WE (2014) Residence of Streptococcus pneumoniae and Moraxella catarrhalis within polymicrobial biofilm promotes antibiotic resistance and bacterial persistence in vivo. Pathog Dis 70: 268–276. Peters BM, Ovchinnikova ES, Krom BP, Schlecht LM, Zhou H, Hoyer LL, Busscher HJ, van der Mei HC, Jabra-Rizk MA & Shirtliff ME (2012) Staphylococcus aureus adherence to Candida albicans hyphae is mediated by the hyphal adhesin Als3p. Microbiology 158: 2975–2986. Van Acker H, Van Dijck P & Coenye T (2014) Molecular mechanisms of antimicrobial resistance in bacterial and fungal biofilms. Trends Microbiol DOI: 10.1016/j.tim.2014.02.001.
Pathogens and Disease (2014), 70, 203–204, © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved
EDITORIAL
Microbial biofilms – the coming of age of a research field DOI: 10.1111/2049-632X.12169
After successful meetings in Rome (2009) and Copenhagen (2011), the Biofilm Study Group of the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) (ESGB) organized the third EuroBiofilms meeting in Ghent (Belgium), from September 9 to September 12, 2013. With close to 300 participants coming from 30 different countries and more than 200 submitted abstracts, the meeting was very successful. It is clear that the field of microbial biofilms has come a long way since the early studies on biofilms (in the 1920s and 1930s, see the historical overview written by Niels Hoiby in this issue; Hoiby, 2014). The field has benefited dramatically from advances in our understanding of the molecular biology of microorganisms as well as from technological advances within microscopy techniques and methods for culture-independent investigation of microbial communities. While simple in vitro model systems are still very valuable to study fundamental aspects of the social behavior of microorganisms, we are gradually developing the capabilities of studying microbial biofilms under in vivo conditions. Results from these in vivo studies clearly indicate that the structure of many in vivo biofilms is very different from what is typically seen in in vitro biofilms and the use of in vivo models allows researchers to dissect the interplay between the host immune response and the microbial biofilm (Bjarnsholt et al., 2013). In addition, there is growing interest in and need for studying multispecies biofilms, both in in vitro and in vivo model systems (Burmølle et al., 2014). Particularly interesting in this regard are studies focusing on interactions between fungi (e.g. Candida albicans) and bacteria (e.g. Streptococcus mutans, Staphylococcus aureus, and S. epidermidis) (Peters et al., 2012; Beaussart et al., 2013; Metwalli et al., 2013). Despite considerable progress in this area over the last decade, much still remains to be learned about resistance, tolerance, and persistence in microbial biofilms. Resistance, tolerance, and persistence all contribute to the frequent failure of antimicrobial therapy directed against biofilm-related infections. While a picture starts to emerge where protection against oxidative stress, expression of efflux pumps, and protection provided by matrix polysaccharides all contribute to the biofilm-specific phenotype (Van Acker et al., 2014), it is still not completely clear how these mechanisms are regulated in different bacteria and fungi. In addition, there is growing evidence that the outcome of antimicrobial therapy is also determined by the composition of the biofilm and the interactions between different organisms in a multispecies biofilms, and it is often observed that the simultaneous presence and interaction of different microorganisms in an infection
can lead to failure of antimicrobial therapy (for example Perez et al., 2014). An important aspect of future biofilm research is the need for standardization, and in this regard, two European initiatives stand out. First, the Biofomics platform was created for the systematic and large-scale compilation, processing, and analysis of biofilm data from high-throughput experiments. This ‘biofilm database’ can be accessed at http://biofomics.org/ and is accompanied by the Minimum Information About a Biofilm Experiment (MIABiE) initiative. MIABiE presents guidelines about the data that need to be made available in order for the procedure and results of a particular experiment to be easily and unequivocally interpreted and – equally important – reproduced (Lourencßo et al., 2014). Secondly, within the framework of the ESGB, Niels Hoiby is coordinating an initiative to develop clinical guidelines for the diagnosis and treatment of biofilm infections. Both initiatives were presented at the Eurobiofilms 2013 meeting in Ghent, and useful input from the audience was obtained. The groups behind both initiatives will remain in touch with the biofilm community to constantly improve and update the guidelines and recommendations. This thematic issue contains 27 papers (including seven MiniReviews) that highlight some of the trends in biofilm research, as presented at Eurobiofilms 2013. We would like to take the opportunity to thank our sponsors (the Federation of European Biochemical Societies, the Research Foundation – Flanders, the Belgian Science Policy Office, the Faculty of Pharmaceutical Sciences of Ghent University and VIB), ESCMID (for providing attendance grants to 14 participants), and all participants. Finally, we look forward to seeing you at the fourth Eurobiofilms meeting that will be hosted by Dr Veronika Hola in Brno (Czech Republic) in 2015.
Tom Coenye Guest Editor Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium ESCMID Biofilm Study Group E-mail: [email protected] Patrick Van Dijck Guest Editor Department of Molecular Microbiology, VIB, and Laboratory of Molecular Cell Biology, KU Leuven, Leuven, Belgium E-mail: [email protected]
Pathogens and Disease (2014), 70, 203–204, © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved
203
Editorial
Thomas Bjarnsholt Guest Editor Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health Sciences, and Department for Clinical Microbiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark ESCMID Biofilm Study Group E-mail: [email protected] Ake Forsberg Issue Editor Department of Molecular Biology, Umea University, Umea, Sweden E-mail: [email protected] References Beaussart A, Herman P, El-Kirat-Chatel S, Lipke P, Kucharikova S, ^ne Y (2013) Single-cell force spectroscopy of Van Dijck P & Dufre the medically-important Staphylococcus epidermidis-Candida albicans interaction. Nanoscale 5: 10894–10900. Bjarnsholt T, Alhede M, Alhede M, Eickhardt-Sørensen SR, Moser €hl M, Jensen PØ & Høiby N (2013) The in vivo biofilm. C, Ku Trends Microbiol 21: 466–474.
204
Burmølle M, Ren D, Bjarnsholt T & Sørensen SJ (2014) Interactions in multispecies biofilms: do they actually matter? Trends Microbiol 22: 84–91. Hoiby N. (2014) A personal history of research on microbial biofilms and biofilm infections. Pathog Dis 70: 205–211. Lourencßo A, Coenye T, Goeres D et al. (2014) Minimum information about a biofilm experiment (MIABiE): standards for reporting experiments and data on sessile microbial communities living at interfaces. Pathog Dis 70: 238–244. Metwalli KH, Khan SA, Krom BP & Jabra-Rizk MA (2013) Streptococcus mutans, Candida albicans, and the human mouth: a sticky situation. PLoS Pathog 9: e1003616. Perez AC, Pang B, King LB, Tan L, Murrah KA, Reimche JL, Wren JT, Richardson SH, Ghandi U & Swords WE (2014) Residence of Streptococcus pneumoniae and Moraxella catarrhalis within polymicrobial biofilm promotes antibiotic resistance and bacterial persistence in vivo. Pathog Dis 70: 268–276. Peters BM, Ovchinnikova ES, Krom BP, Schlecht LM, Zhou H, Hoyer LL, Busscher HJ, van der Mei HC, Jabra-Rizk MA & Shirtliff ME (2012) Staphylococcus aureus adherence to Candida albicans hyphae is mediated by the hyphal adhesin Als3p. Microbiology 158: 2975–2986. Van Acker H, Van Dijck P & Coenye T (2014) Molecular mechanisms of antimicrobial resistance in bacterial and fungal biofilms. Trends Microbiol DOI: 10.1016/j.tim.2014.02.001.
Pathogens and Disease (2014), 70, 203–204, © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved
