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Slobodianyk-Kolomoiets M, Khlebas S, Mazur I, Rudnieva K, Potochilova V, Iungin O, Kamyshnyi O, Kamyshna I, Potters G, Spiers AJ, Moshynets O. Extracellular host DNA contributes to pathogenic biofilm formation during periodontitis. Front Cell Infect Microbiol 2024; 14:1374817. [PMID: 38779563 PMCID: PMC11109387 DOI: 10.3389/fcimb.2024.1374817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/09/2024] [Indexed: 05/25/2024] Open
Abstract
Introduction Periodontal diseases are known to be associated with polymicrobial biofilms and inflammasome activation. A deeper understanding of the subgingival cytological (micro) landscape, the role of extracellular DNA (eDNA) during periodontitis, and contribution of the host immune eDNA to inflammasome persistence, may improve our understanding of the mechanisms underlaying severe forms of periodontitis. Methods In this work, subgingival biolfilms developing on biologically neutral polyethylene terephthalate films placed in gingival cavities of patients with chronic periodontitis were investigated by confocal laser scanning microscopy (CLSM). This allowed examination of realistic cytological landscapes and visualization of extracellular polymeric substances (EPS) including amyloids, total proteins, carbohydrates and eDNA, as well as comparison with several single-strain in vitro model biofilms produced by oral pathogens such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus gordonii, S. sanguinis and S. mitis. Fluorescence in situ hybridization (FISH) analysis was also used to identify eDNA derived from eubacteria, streptococci and members of the Bacteroides-Porphyromonas-Prevotella (BPP) group associated with periodontitis. Results Analysis of subgingival biofilm EPS revealed low levels of amyloids and high levels of eDNA which appears to be the main matrix component. However, bacterial eDNA contributed less than a third of the total eDNA observed, suggesting that host-derived eDNA released in neutrophil extracellular traps may be of more importance in the development of biofilms causing periodontitis. Discussion eDNA derived from host immunocompetent cells activated at the onset of periodontitis may therefore be a major driver of bacterial persistence and pathogenesis.
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Affiliation(s)
| | - Svitlana Khlebas
- Department of Dentistry, Shupyk National Healthcare University of Ukraine, Kyiv, Ukraine
| | - Iryna Mazur
- Department of Dentistry, Shupyk National Healthcare University of Ukraine, Kyiv, Ukraine
| | - Kateryna Rudnieva
- Central Clinical Diagnostic Laboratory, Kyiv Regional Clinical Hospital, Kyiv, Ukraine
- Department of Microbiology, Virology and Immunology, Bogomolets National Medical Academy, Kyiv, Ukraine
| | | | - Olga Iungin
- Biofilm Study Group, Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
- Department of Biotechnology, Leather and Fur, Faculty of Chemical and Biopharmaceutical Technologies, Kyiv National University of Technologies and Design, Kyiv, Ukraine
| | - Olexandr Kamyshnyi
- Microbiology, Virology and Immunology Department, I. Horbachevsky Ternopil National Medical University, Ternopil, Ukraine
| | - Iryna Kamyshna
- Microbiology, Virology and Immunology Department, I. Horbachevsky Ternopil National Medical University, Ternopil, Ukraine
| | - Geert Potters
- Antwerp Maritime Academy, Antwerp, Belgium
- Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Andrew J. Spiers
- School of Applied Sciences, Abertay University, Dundee, United Kingdom
| | - Olena Moshynets
- Biofilm Study Group, Department of Cell Regulatory Mechanisms, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
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Sharma DK, Rajpurohit YS. Multitasking functions of bacterial extracellular DNA in biofilms. J Bacteriol 2024; 206:e0000624. [PMID: 38445859 PMCID: PMC11025335 DOI: 10.1128/jb.00006-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024] Open
Abstract
Bacterial biofilms are intricate ecosystems of microbial communities that adhere to various surfaces and are enveloped by an extracellular matrix composed of polymeric substances. Within the context of bacterial biofilms, extracellular DNA (eDNA) originates from cell lysis or is actively secreted, where it exerts a significant influence on the formation, stability, and resistance of biofilms to environmental stressors. The exploration of eDNA within bacterial biofilms holds paramount importance in research, with far-reaching implications for both human health and the environment. An enhanced understanding of the functions of eDNA in biofilm formation and antibiotic resistance could inspire the development of strategies to combat biofilm-related infections and improve the management of antibiotic resistance. This comprehensive review encapsulates the latest discoveries concerning eDNA, encompassing its origins, functions within bacterial biofilms, and significance in bacterial pathogenesis.
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Affiliation(s)
- Dhirendra Kumar Sharma
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Schools of Life Sciences, Homi Bhabha National Institute (DAE—Deemed University), Mumbai, India
| | - Yogendra Singh Rajpurohit
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Schools of Life Sciences, Homi Bhabha National Institute (DAE—Deemed University), Mumbai, India
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Brangulis K, Akopjana I, Drunka L, Matisone S, Zelencova-Gopejenko D, Bhattacharya S, Bogans J, Tars K. Members of the paralogous gene family 12 from the Lyme disease agent Borrelia burgdorferi are non-specific DNA-binding proteins. PLoS One 2024; 19:e0296127. [PMID: 38626020 PMCID: PMC11020477 DOI: 10.1371/journal.pone.0296127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 12/06/2023] [Indexed: 04/18/2024] Open
Abstract
Lyme disease is the most prevalent vector-borne infectious disease in Europe and the USA. Borrelia burgdorferi, as the causative agent of Lyme disease, is transmitted to the mammalian host during the tick blood meal. To adapt to the different encountered environments, Borrelia has adjusted the expression pattern of various, mostly outer surface proteins. The function of most B. burgdorferi outer surface proteins remains unknown. We determined the crystal structure of a previously uncharacterized B. burgdorferi outer surface protein BBK01, known to belong to the paralogous gene family 12 (PFam12) as one of its five members. PFam12 members are shown to be upregulated as the tick starts its blood meal. Structural analysis of BBK01 revealed similarity to the coiled coil domain of structural maintenance of chromosomes (SMC) protein family members, while functional studies indicated that all PFam12 members are non-specific DNA-binding proteins. The residues involved in DNA binding were identified and probed by site-directed mutagenesis. The combination of SMC-like proteins being attached to the outer membrane and exposed to the environment or located in the periplasm, as observed in the case of PFam12 members, and displaying the ability to bind DNA, represents a unique feature previously not observed in bacteria.
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Affiliation(s)
| | - Inara Akopjana
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Laura Drunka
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | | | | | | | - Janis Bogans
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Kaspars Tars
- Latvian Biomedical Research and Study Centre, Riga, Latvia
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4
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Mattos-Graner RO, Klein MI, Alves LA. The complement system as a key modulator of the oral microbiome in health and disease. Crit Rev Microbiol 2024; 50:138-167. [PMID: 36622855 DOI: 10.1080/1040841x.2022.2163614] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 01/10/2023]
Abstract
In this review, we address the interplay between the complement system and host microbiomes in health and disease, focussing on oral bacteria known to contribute to homeostasis or to promote dysbiosis associated with dental caries and periodontal diseases. Host proteins modulating complement activities in the oral environment and expression profiles of complement proteins in oral tissues were described. In addition, we highlight a sub-set of bacterial proteins involved in complement evasion and/or dysregulation previously characterized in pathogenic species (or strains), but further conserved among prototypical commensal species of the oral microbiome. Potential roles of these proteins in host-microbiome homeostasis and in the emergence of commensal strain lineages with increased virulence were also addressed. Finally, we provide examples of how commensal bacteria might exploit the complement system in competitive or cooperative interactions within the complex microbial communities of oral biofilms. These issues highlight the need for studies investigating the effects of the complement system on bacterial behaviour and competitiveness during their complex interactions within oral and extra-oral host sites.
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Affiliation(s)
- Renata O Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas (UNICAMP), Sao Paulo, Brazil
| | - Marlise I Klein
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas (UNICAMP), Sao Paulo, Brazil
| | - Lívia Araújo Alves
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas (UNICAMP), Sao Paulo, Brazil
- School of Dentistry, Cruzeiro do Sul University (UNICSUL), Sao Paulo, Brazil
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5
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De S, Hakansson AP. Measuring Niche-Associated Metabolic Activity in Planktonic and Biofilm Bacteria. Methods Mol Biol 2023; 2674:3-32. [PMID: 37258957 DOI: 10.1007/978-1-0716-3243-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Most pathobionts of the respiratory tract form biofilms during asymptomatic colonization to survive and persist in this niche. Environmental changes of the host niche, often resulting from infection with respiratory viruses, changes of the microbiota composition, or other host assaults, can result in biofilm dispersion and spread of bacteria to other host niches, resulting in infections, such as otitis media, pneumonia, sepsis, and meningitis. The niches that these bacteria encounter during colonization and infection vary markedly in nutritional availability and contain different carbon sources and levels of other essential nutrients needed for bacterial growth and survival. As these niche-related nutritional variations regulate bacterial behavior and phenotype, a better understanding of bacterial niche-associated metabolic activity is likely to provide a broader understanding of bacterial pathogenesis. In this chapter, we use Streptococcus pneumoniae as a model respiratory pathobiont. We describe methods and models used to grow bacteria planktonically or to form biofilms in vitro by incorporating crucial host environmental factors, including the various carbon sources associated with specific niches, such as the nasopharynx or bloodstream. We then present methods describing how these models can be used to study bacterial phenotypes and their association with metabolic energy production and the generation of fermentation products.
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Affiliation(s)
- Supradipta De
- Department of Translational Medicine, Division of Experimental Infection Medicine, Wallenberg Laboratory, Lund University, Malmö, Sweden
| | - Anders P Hakansson
- Department of Translational Medicine, Division of Experimental Infection Medicine, Wallenberg Laboratory, Lund University, Malmö, Sweden.
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Ji H, Zhou Y, Zhang L, Wang Y, Zhang F, Bai J, Li Q, Zhang Z. Function analysis of choline binding domains (CBDs) of LytA, LytC and CbpD in biofilm formation of Streptococcus pneumoniae. Microb Pathog 2023; 174:105939. [PMID: 36521655 DOI: 10.1016/j.micpath.2022.105939] [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] [Received: 07/09/2022] [Revised: 11/21/2022] [Accepted: 12/08/2022] [Indexed: 12/15/2022]
Abstract
Biofilm formation is an important strategy for the colonization of Streptococcus pneumoniae, which can increase the capacity to evade antibiotic and host immune stress. Extracellular choline-binding proteins (CBPs) are required for successful biofilm formation, but the function of extracellular CBPs in the process of biofilm formation is not fully understood. In this study, we tend to analyze the functions of LytA, LytC and CbpD in biofilm formation by in vitro studies with their choline-binding domains (CBDs). Biofilm formation of S. pneumoniae was enhanced when cultured in medium supplemented with CBD-C and CBD-D. Parallel assays with ChBp-Is (choline binding repeats with different C-terminal tails) and character analysis of CBDs reveal a higher isoelectric point (pI) is related to promotion of biofilm formation. Phenotype characterization of biofilms revel CBD-C and CBD-D function differently, CBD-C promoting the formation of membrane-like structures and CBD-D promoting the formation of regular reticular structures. Gene expression analysis reveals membrane transport pathways are influenced with the binding of CBDs, among which the phosphate uptake and PTS of galactose pathways are both up-regulated under conditions with CBDs. Further, extracellular substances detection revealed that extracellular proteins increased with CBD-A and CBD-D, exhibiting as increase in extracellular high molecular weight proteins. Extracellular DNA increased under CBD-A but decreased under CBD-C and CBD-D; Extracellular phosphate increased under CBD-C. These support the alterations in membrane transport pathways, and reveal diverse reactions to extracellular protein, DNA and phosphate of these three CBDs. Overall, our results indicated extracellular CBP participate in biofilm formation by affecting surface charge and membrane transport pathways of pneumococcal cells, as well as promoting reactions to extracellular substances.
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Affiliation(s)
- Hongsheng Ji
- School of Public Health, Southwest Medical University, Sichuan, China
| | - Yingshun Zhou
- Department of Pathogenic Biology, School of Basic Medicine, Southwest Medical University, China
| | - Luhua Zhang
- Department of Pathogenic Biology, School of Basic Medicine, Southwest Medical University, China
| | - Ying Wang
- Department of Pathogenic Biology, School of Basic Medicine, Southwest Medical University, China
| | - Feiyang Zhang
- Department of Pathogenic Biology, School of Basic Medicine, Southwest Medical University, China
| | - Jiawei Bai
- Department of Pathogenic Biology, School of Basic Medicine, Southwest Medical University, China
| | - Qin Li
- Department of Pathogenic Biology, School of Basic Medicine, Southwest Medical University, China
| | - Zhikun Zhang
- Department of Pathogenic Biology, School of Basic Medicine, Southwest Medical University, China.
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Yang Y, Li M, Zheng X, Ma H, Nerenberg R, Chai H. Extracellular DNA plays a key role in the structural stability of sulfide-based denitrifying biofilms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155822. [PMID: 35561912 DOI: 10.1016/j.scitotenv.2022.155822] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Sulfide-based biofilm processes are increasingly used for wastewater denitrification, yet little is known about the extracellular polymeric substance (EPS) composition of sulfide-oxidizing biofilms. This can have an important impact on biofilm mechanical strength and stability. In this research, the properties and roles of EPS components in biofilm stability were investigated. Weak biofilm stability characterized by high roughness and numerous "needle" structures was visualized by optical coherence tomography (OCT) and microscopy. A high abundance of extracellular DNA (eDNA) and a low protein to polysaccharide ratio were found in the biofilm. The roles of eDNA, protein and polysaccharide in biofilm cohesion and adhesion were identified through enzyme treatment and atomic force microscopy (AFM). The enzymatic hydrolysis of eDNA increased the elastic modulus of biofilms by 57 times and reduced the adhesion energy by 96%. The hydrolysis of proteins led to an increase of elastic modulus by 27 times and a loss of adhesion energy by 95.5%. The enzymatic hydrolysis of polysaccharides caused minimal changes in elastic modulus and adhesion energy. These results suggest that eDNA was the key EPS component for biofilm cohesion and adhesion, possibly because it provided special binding sites and can form strong cross-linking with magnesium or other multivalent cations. This study provided new insights into the role of eDNA in biofilm stability and shed light on the development of sulfide-based denitrifying biofilms.
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Affiliation(s)
- Yan Yang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China; Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Xiong Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Haiyuan Ma
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Hongxiang Chai
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
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Amyloid-containing biofilms and autoimmunity. Curr Opin Struct Biol 2022; 75:102435. [PMID: 35863164 PMCID: PMC9847210 DOI: 10.1016/j.sbi.2022.102435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/08/2022] [Accepted: 06/20/2022] [Indexed: 01/21/2023]
Abstract
Bacteria are microscopic, single-celled organisms known for their ability to adapt to their environment. In response to stressful environmental conditions or in the presence of a contact surface, they commonly form multicellular aggregates called biofilms. Biofilms form on various abiotic or biotic surfaces through a dynamic stepwise process involving adhesion, growth, and extracellular matrix production. Biofilms develop on tissues as well as on implanted devices during infections, providing the bacteria with a mechanism for survival under harsh conditions including targeting by the immune system and antimicrobial therapy. Like pathogenic bacteria, members of the human microbiota can form biofilms. Biofilms formed by enteric bacteria contribute to several human diseases including autoimmune diseases and cancer. However, until recently the interactions of immune cells with biofilms had been mostly uncharacterized. Here, we will discuss how components of the enteric biofilm produced in vivo, specifically amyloid curli and extracellular DNA, could be interacting with the host's immune system causing an unpredicted immune response.
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Xu RZ, Cao JS, Feng G, Luo JY, Wu Y, Ni BJ, Fang F. Modeling molecular structure and behavior of microbial extracellular polymeric substances through interacting-particle reaction dynamics. CHEMICAL ENGINEERING JOURNAL ADVANCES 2021. [DOI: 10.1016/j.ceja.2021.100154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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10
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Extracellular DNA (eDNA). A Major Ubiquitous Element of the Bacterial Biofilm Architecture. Int J Mol Sci 2021; 22:ijms22169100. [PMID: 34445806 PMCID: PMC8396552 DOI: 10.3390/ijms22169100] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/22/2022] Open
Abstract
After the first ancient studies on microbial slime (the name by which the biofilm matrix was initially indicated), multitudes of studies on the morphology, composition and physiology of biofilms have arisen. The emergence of the role that biofilms play in the pathogenesis of recalcitrant and persistent clinical infections, such as periprosthetic orthopedic infections, has reinforced scientific interest. Extracellular DNA (eDNA) is a recently uncovered component that is proving to be almost omnipresent in the extracellular polymeric substance (EPS) of biofilm. This macromolecule is eliciting unprecedented consideration for the critical impact on the pathogenesis of chronic clinical infections. After a systematic review of the literature, an updated description of eDNA in biofilms is presented, with a special focus on the latest findings regarding its fundamental structural role and the contribution it makes to the complex architecture of bacterial biofilms through interactions with a variety of other molecular components of the biofilm matrix.
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Deciphering Streptococcal Biofilms. Microorganisms 2020; 8:microorganisms8111835. [PMID: 33233415 PMCID: PMC7700319 DOI: 10.3390/microorganisms8111835] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/10/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.
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Iwahashi J, Kamei K, Watanabe H. Disruption of Aspergillus fumigatus biofilm by Streptococcus pneumoniae: Mycelial fragmentation by hydrogen peroxide. J Infect Chemother 2020; 26:831-837. [PMID: 32414689 DOI: 10.1016/j.jiac.2020.03.015] [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] [Received: 11/15/2019] [Revised: 02/07/2020] [Accepted: 03/24/2020] [Indexed: 01/06/2023]
Abstract
Biofilm is a complex structure consisting of microorganisms such as bacteria, fungi and an extracellular matrix (ECM). Biofilms are involved in most microbial infections and show persistent resistance to antibiotic treatment and immune response. Both Aspergillus fumigatus and Streptococcus pneumoniae are colonizers that can form biofilms in the respiratory tract. These pathogens have been simultaneously isolated from the same patient, but their interaction is poorly understood. We observed morphological changes in single- and mixed-species biofilms prepared for confocal laser scanning microscopy and scanning electron microscopy (SEM). Pneumococci suppressed the development of a fungal biofilm, and it even disrupted a preformed fungal biofilm. When a preformed fungal biofilm was treated with pneumococci, the mycelial network was fragmented, and only bacteria could develop. SEM revealed that the fragmented mycelium was further disrupted into fine filaments as treatment time progressed, and that the ECM of the preformed fungal biofilm had disappeared. The pneumococcal culture supernatant contained mycelial fragmentation activity that was heat-sensitive. The culture supernatant of a mutant pneumococcal strain deficient in pneumolysin (Δply) also exhibited the mycelial fragmentation activity. Enolase and lactate oxidase, which are involved in glycolysis and hydrogen peroxide production, were identified in the culture supernatant of the Δply mutant. Neither the wild type nor the mutant strain could fragment the mycelium in the presence of catalase. These data suggest that hydrogen peroxide could fragment the mycelium and would terminate the co-existence of A. fumigatus and S. pneumoniae in biofilm.
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Affiliation(s)
- Jun Iwahashi
- Department of Infection Control and Prevention, Kurume University School of Medicine, 67 Asahi-machi, Kurume City, Fukuoka 830-0011, Japan.
| | - Katsuhiko Kamei
- Division of Clinical Research, Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8673, Japan
| | - Hiroshi Watanabe
- Department of Infection Control and Prevention, Kurume University School of Medicine, 67 Asahi-machi, Kurume City, Fukuoka 830-0011, Japan
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Domenech M, García E. The N-Acetylglucosaminidase LytB of Streptococcus pneumoniae Is Involved in the Structure and Formation of Biofilms. Appl Environ Microbiol 2020; 86:e00280-20. [PMID: 32198170 PMCID: PMC7205503 DOI: 10.1128/aem.00280-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/15/2020] [Indexed: 02/07/2023] Open
Abstract
The N-acetylglucosaminidase LytB of Streptococcus pneumoniae is involved in nasopharyngeal colonization and is responsible for cell separation at the end of cell division; thus, ΔlytB mutants form long chains of cells. This paper reports the construction and properties of a defective pneumococcal mutant producing an inactive LytB protein (LytBE585A). It is shown that an enzymatically active LytB is required for in vitro biofilm formation, as lytB mutants (either ΔlytB or producing the inactive LytBE585A) are incapable of forming substantial biofilms, despite that extracellular DNA is present in the biofilm matrix. Adding small amounts (0.5 to 2.0 μg/ml) of exogenous LytB or some LytB constructs restored the biofilm-forming capacity of lytB mutants to wild-type levels. The LytBE585A mutant formed biofilm more rapidly than ΔlytB mutants in the presence of LytB. This suggests that the mutant protein acted in a structural role, likely through the formation of complexes with extracellular DNA. The chain-dispersing capacity of LytB allowed the separation of daughter cells, presumably facilitating the formation of microcolonies and, finally, of biofilms. A role for the possible involvement of LytB in the synthesis of the extracellular polysaccharide component of the biofilm matrix is also discussed.IMPORTANCE It has been previously accepted that biofilm formation in S. pneumoniae must be a multigenic trait because the mutation of a single gene has led to only to partial inhibition of biofilm production. In the present study, however, evidence that the N-acetylglucosaminidase LytB is crucial in biofilm formation is provided. Despite the presence of extracellular DNA, strains either deficient in LytB or producing a defective LytB enzyme formed only shallow biofilms.
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Affiliation(s)
- Mirian Domenech
- Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Ernesto García
- Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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Host-adapted lactobacilli in food fermentations: impact of metabolic traits of host adapted lactobacilli on food quality and human health. Curr Opin Food Sci 2020. [DOI: 10.1016/j.cofs.2020.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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15
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Desai S, Sanghrajka K, Gajjar D. High Adhesion and Increased Cell Death Contribute to Strong Biofilm Formation in Klebsiella pneumoniae. Pathogens 2019; 8:pathogens8040277. [PMID: 31805671 PMCID: PMC6963951 DOI: 10.3390/pathogens8040277] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/14/2019] [Accepted: 11/28/2019] [Indexed: 01/29/2023] Open
Abstract
Klebsiella pneumoniae (Kp), is a frequent cause of hospital and community-acquired infections and WHO had declared it as a "priority pathogen". Biofilm is a major virulence factor of Kp and yet the mechanism of strong biofilm formation in Kp is unclear. A key objective of the present study is to investigate the differences between strong and weak biofilms formed by clinical isolates of Kp on various catheters and in different media conditions and to identify constituents contributing to strong biofilm formation. Quantification of matrix components (extracellular DNA (eDNA), protein, exopolysaccharides (EPS), and bacterial cells), confocal laser scanning microscopy (CLSM), field emission gun scanning electron microscopy (FEG-SEM) and flow-cytometry analysis were performed to compare strong and weak biofilm matrix. Our results suggest increased biofilm formation on latex catheters compared to silicone and silicone-coated latex catheters. Higher amounts of eDNA, protein, EPS, and dead cells were observed in the strong biofilm of Kp. High adhesion capacity and cell death seem to play a major role in formation of strong Kp biofilms. The enhanced eDNA, EPS, and protein in the biofilm matrix appear as a consequence of increased cell death.
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Silva MD, Sillankorva S. Otitis media pathogens – A life entrapped in biofilm communities. Crit Rev Microbiol 2019; 45:595-612. [DOI: 10.1080/1040841x.2019.1660616] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Maria Daniela Silva
- CEB – Centre of Biological Engineering, LIBRO – Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Braga, Portugal
| | - Sanna Sillankorva
- CEB – Centre of Biological Engineering, LIBRO – Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Braga, Portugal
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17
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Chao Y, Bergenfelz C, Hakansson AP. Growing and Characterizing Biofilms Formed by Streptococcus pneumoniae. Methods Mol Biol 2019; 1968:147-171. [PMID: 30929213 DOI: 10.1007/978-1-4939-9199-0_13] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
It is estimated that over 80% of bacterial infections are associated with biofilm formation. Biofilms are organized bacterial communities formed on abiotic surfaces, such as implanted or inserted medical devices, or on biological surfaces, such as epithelial linings and mucosal surfaces. Biofilm growth is advantageous for the bacterial organism as it protects the bacteria from antimicrobial host factors and allows the bacteria to reside in the host without causing excessive inflammation. Like many other opportunistic pathogens of the respiratory tract, Streptococcus pneumoniae forms biofilms during asymptomatic carriage, which promotes, among other things, persistence in the niche, intraspecies and interspecies communication, and spread of bacterial DNA. Changes within the colonizing environment resulting from host assaults, such as virus infection, can induce biofilm dispersion where bacteria leave the biofilm and disseminate to other sites with ensuing infection. In this chapter, we present methodology to form complex biofilms in the nasopharynx of mice and to evaluate the biofilm structure and function in this environment. Furthermore, we present methods that recapitulate this biofilm phenotype in vitro by incorporating crucial factors associated with the host environment and describe how these models can be used to study biofilm function, transformation, and dispersion.
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Affiliation(s)
- Yashuan Chao
- Wallenberg Laboratory, Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Caroline Bergenfelz
- Wallenberg Laboratory, Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Anders P Hakansson
- Wallenberg Laboratory, Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden.
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18
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Roig-Molina E, Domenech M, Retamosa MDG, Nácher-Vázquez M, Rivas L, Maestro B, García P, García E, Sanz JM. Widening the antimicrobial spectrum of esters of bicyclic amines: In vitro effect on gram-positive Streptococcus pneumoniae and gram-negative non-typeable Haemophilus influenzae biofilms. Biochim Biophys Acta Gen Subj 2018; 1863:96-104. [PMID: 30292448 DOI: 10.1016/j.bbagen.2018.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 09/10/2018] [Accepted: 10/02/2018] [Indexed: 11/19/2022]
Abstract
Antibiotic resistance is a global current threat of increasing importance. Moreover, biofilms represent a medical challenge since the inherent antibiotic resistance of their producers demands the use of high doses of antibiotics over prolonged periods. Frequently, these therapeutic measures fail, contributing to bacterial persistence, therefore demanding the development of novel antimicrobials. Esters of bicyclic amines (EBAs), which are strong inhibitors of Streptococcus pneumoniae growth, were initially designed as inhibitors of pneumococcal choline-binding proteins on the basis of their structural analogy to the choline residues in the cell wall. However, instead of mimicking the characteristic cell chaining phenotype caused by exogenously added choline on planktonic cultures of pneumococcal cells, EBAs showed an unexpected lytic activity. In this work we demonstrate that EBAs display a second, and even more important, function as cell membrane destabilizers. We then assayed the inhibitory and disintegrating activity of these molecules on pneumococcal biofilms. The selected compound (EBA 31) produced the highest effect on S. pneumoniae (encapsulated and non-encapsulated) biofilms at very low concentrations. EBA 31 was also effective on mixed biofilms of non-encapsulated S. pneumoniae plus non-typeable Haemophilus influenzae, two pathogens frequently forming a self-produced biofilm in the human nasopharynx. These results support the role of EBAs as a promising alternative for the development of novel, broad-range antimicrobial drugs encompassing both Gram-positive and Gram-negative pathogens.
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Affiliation(s)
- Emma Roig-Molina
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda Universidad s/n, Elche 03202, Spain
| | - Mirian Domenech
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - María de Gracia Retamosa
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda Universidad s/n, Elche 03202, Spain
| | | | - Luis Rivas
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Beatriz Maestro
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda Universidad s/n, Elche 03202, Spain
| | - Pedro García
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Ernesto García
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Jesús M Sanz
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda Universidad s/n, Elche 03202, Spain; Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Ramiro de Maeztu, 9, 28040 Madrid, Spain.
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19
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Hakansson AP, Orihuela CJ, Bogaert D. Bacterial-Host Interactions: Physiology and Pathophysiology of Respiratory Infection. Physiol Rev 2018; 98:781-811. [PMID: 29488821 PMCID: PMC5966719 DOI: 10.1152/physrev.00040.2016] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 02/06/2023] Open
Abstract
It has long been thought that respiratory infections are the direct result of acquisition of pathogenic viruses or bacteria, followed by their overgrowth, dissemination, and in some instances tissue invasion. In the last decades, it has become apparent that in contrast to this classical view, the majority of microorganisms associated with respiratory infections and inflammation are actually common members of the respiratory ecosystem and only in rare circumstances do they cause disease. This suggests that a complex interplay between host, environment, and properties of colonizing microorganisms together determines disease development and its severity. To understand the pathophysiological processes that underlie respiratory infectious diseases, it is therefore necessary to understand the host-bacterial interactions occurring at mucosal surfaces, along with the microbes inhabiting them, during symbiosis. Current knowledge regarding host-bacterial interactions during asymptomatic colonization will be discussed, including a plausible role for the human microbiome in maintaining a healthy state. With this as a starting point, we will discuss possible disruptive factors contributing to dysbiosis, which is likely to be a key trigger for pathobionts in the development and pathophysiology of respiratory diseases. Finally, from this renewed perspective, we will reflect on current and potential new approaches for treatment in the future.
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Affiliation(s)
- A P Hakansson
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
| | - C J Orihuela
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
| | - D Bogaert
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University , Lund , Sweden ; Department of Microbiology, University of Alabama at Birmingham , Birmingham, Alabama ; and Center for Inflammation Research, Queens Medical Research Institute, University of Edinburgh , Edinburgh , United Kingdom
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20
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Yadav MK, Go YY, Kim SH, Chae SW, Song JJ. Antimicrobial and Antibiofilm Effects of Human Amniotic/Chorionic Membrane Extract on Streptococcus pneumoniae. Front Microbiol 2017; 8:1948. [PMID: 29089928 PMCID: PMC5641382 DOI: 10.3389/fmicb.2017.01948] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/22/2017] [Indexed: 01/11/2023] Open
Abstract
Background:Streptococcus pneumoniae colonize the human nasopharynx in the form of biofilms. The biofilms act as bacterial reservoirs and planktonic bacteria from these biofilms can migrate to other sterile anatomical sites to cause pneumonia, otitis media (OM), bacteremia and meningitis. Human amniotic membrane contains numerous growth factors and antimicrobial activity; however, these have not been studied in detail. In this study, we prepared amniotic membrane extract and chorionic membrane extract (AME/CME) and evaluated their antibacterial and antibiofilm activities against S. pneumoniae using an in vitro biofilm model and in vivo OM rat model. Materials and Methods: The AME/CME were prepared and protein was quantified using DCTM (detergent compatible) method. The minimum inhibitory concentrations were determined using broth dilution method, and the synergistic effect of AME/CME with Penicillin-streptomycin was detected checkerboard. The in vitro biofilm and in vivo colonization of S. pneumoniae were studied using microtiter plate assay and OM rat model, respectively. The AME/CME-treated biofilms were examined using scanning electron microscope and confocal microscopy. To examine the constituents of AME/CME, we determined the proteins and peptides of AME/CME using tandem mass tag-based quantitative mass spectrometry. Results: AME/CME treatment significantly (p < 0.05) inhibited S. pneumoniae growth in planktonic form and in biofilms. Combined application of AME/CME and Penicillin-streptomycin solution had a synergistic effect against S. pneumoniae. Biofilms grown with AME/CME were thin, scattered, and unorganized. AME/CME effectively eradicated pre-established pneumococci biofilms and has a bactericidal effect. AME treatment significantly (p < 0.05) reduced bacterial colonization in the rat middle ear. The proteomics analysis revealed that the AME/CME contains hydrolase, ribonuclease, protease, and other antimicrobial proteins and peptides. Conclusion: AME/CME inhibits S. pneumoniae growth in the planktonic and biofilm states via its antimicrobial proteins and peptides. AME/CME are non-cytotoxic, natural human product; therefore, they may be used alone or with antibiotics to treat S. pneumoniae infections.
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Affiliation(s)
- Mukesh K Yadav
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea.,Institute for Medical Device Clinical Trials, Korea University College of Medicine, Seoul, South Korea
| | - Yoon Y Go
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Shin Hye Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Sung-Won Chae
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Jae-Jun Song
- Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
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A Quorum-Sensing System That Regulates Streptococcus pneumoniae Biofilm Formation and Surface Polysaccharide Production. mSphere 2017; 2:mSphere00324-17. [PMID: 28932816 PMCID: PMC5597970 DOI: 10.1128/msphere.00324-17] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 07/31/2017] [Indexed: 12/13/2022] Open
Abstract
Quorum sensing regulates bacterial social behaviors by production, secretion, and sensing of pheromones. In this study, we characterized a new quorum-sensing system of the Rgg/SHP class in S. pneumoniae D39. The system was found to directly induce the expression of a single gene cluster comprising the gene for the SHP pheromone and genes with putative functions in capsule synthesis. Capsule size, as measured by dextran exclusion, was increased by SHP exposure in R36A, an unencapsulated derivative of D39. In the encapsulated parent strain, overexpression of the gene cluster increased capsule size, supporting the role of Rgg/SHP in the synthesis of surface polysaccharides. Further, we found that biofilm formation on epithelial cells was reduced by overexpression of the system and increased in a mutant with an rgg deletion. Placing surface polysaccharide expression under quorum-sensing regulation may enable S. pneumoniae to tune interactions with the host and other bacteria in accordance with environmental and cell density conditions. Despite vaccines, Streptococcus pneumoniae kills more than a million people yearly. Thus, understanding how pneumococci transition from commensals to pathogens is particularly relevant. Quorum sensing regulates collective behaviors and thus represents a potential driver of commensal-to-pathogen transitions. Rgg/small hydrophobic peptide (SHP) quorum-sensing systems are widespread in streptococci, yet they remain largely uncharacterized in S. pneumoniae. Using directional transcriptome sequencing, we show that the S. pneumoniae D39 Rgg0939/SHP system induces the transcription of a single gene cluster including shp and capsule gene homologs. Capsule size measurements determined by fluorescein isothiocyanate-dextran exclusion allowed assignment of the system to the regulation of surface polysaccharide expression. We found that the SHP pheromone induced exopolysaccharide expression in R36A, an unencapsulated derivative of D39. In the encapsulated parent strain, overexpression of the Rgg system resulted in a mutant with increased capsule size. In line with previous studies showing that capsule expression is inversely associated with biofilm formation, we found that biofilm formed on lung epithelial cells was decreased in the overexpression strain and increased in an rgg deletion mutant. Although no significant differences were observed between D39 and the rgg deletion mutant in a mouse model of lung infection, in competitive assays, overexpression reduced fitness. This is the first study to reveal a quorum-sensing system in streptococci that regulates exopolysaccharide synthesis from a site distinct from the original capsule locus. IMPORTANCE Quorum sensing regulates bacterial social behaviors by production, secretion, and sensing of pheromones. In this study, we characterized a new quorum-sensing system of the Rgg/SHP class in S. pneumoniae D39. The system was found to directly induce the expression of a single gene cluster comprising the gene for the SHP pheromone and genes with putative functions in capsule synthesis. Capsule size, as measured by dextran exclusion, was increased by SHP exposure in R36A, an unencapsulated derivative of D39. In the encapsulated parent strain, overexpression of the gene cluster increased capsule size, supporting the role of Rgg/SHP in the synthesis of surface polysaccharides. Further, we found that biofilm formation on epithelial cells was reduced by overexpression of the system and increased in a mutant with an rgg deletion. Placing surface polysaccharide expression under quorum-sensing regulation may enable S. pneumoniae to tune interactions with the host and other bacteria in accordance with environmental and cell density conditions.
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22
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Ackerman DL, Doster RS, Weitkamp JH, Aronoff DM, Gaddy JA, Townsend SD. Human Milk Oligosaccharides Exhibit Antimicrobial and Antibiofilm Properties against Group B Streptococcus. ACS Infect Dis 2017; 3:595-605. [PMID: 28570820 PMCID: PMC5868341 DOI: 10.1021/acsinfecdis.7b00064] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Streptococcus agalactiae (Group B Streptococcus, GBS) is a Gram-positive bacterial pathogen that causes invasive infections in both children and adults. During pregnancy, GBS is a significant cause of infection of the fetal membranes (chorioamnionitis), which can lead to intra-amniotic infection, preterm birth, stillbirth, and neonatal sepsis. Recently, breastfeeding has been thought to represent a potential mode of GBS transmission from mother to newborn, which might increase the risk for late-onset sepsis. Little is known, however, about the molecular components of breast milk that may support or prevent GBS colonization. In this study, we examine how human milk oligosaccharides (HMOs) affect the pathogenesis of GBS. HMOs from discrete donor samples were isolated and profiled by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Growth and biofilm assays show that HMOs from mothers of specific milk groups can modulate the growth and biofilm formation of GBS. High-resolution field-emission gun scanning electron microscopy (SEM) and confocal laser scanning microscopy confirmed the quantitative biofilm assays and demonstrated cell arrangement perturbations in bacterial cultures treated with specific oligosaccharides. These findings demonstrate that HMOs affect the growth and cell biology of GBS. Finally, this study provides the first example of HMOs functioning as antibiofilm agents against GBS.
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Affiliation(s)
- Dorothy L. Ackerman
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, Nashville, TN 37235
| | - Ryan S. Doster
- Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South D-3100 Medical Center North, Nashville, TN 37232
| | - Jörn-Hendrik Weitkamp
- Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South D-3100 Medical Center North, Nashville, TN 37232
- Department of Pediatrics, Monroe Carell Jr. Children’s Hospital at Vanderbilt, 2200 Children’s Way, Suite 2404, Nashville, TN 37232
| | - David M. Aronoff
- Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South D-3100 Medical Center North, Nashville, TN 37232
| | - Jennifer A. Gaddy
- Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South D-3100 Medical Center North, Nashville, TN 37232
- Tennessee Valley Healthcare Systems, Department of Veterans Affairs, 1310 24th Avenue South, Nashville, TN 37212
| | - Steven D. Townsend
- Department of Chemistry, Vanderbilt University, 7330 Stevenson Center, Nashville, TN 37235
- Institute of Chemical Biology, Vanderbilt University, 896 Preston Research Building, Nashville, TN 37232-6304
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23
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Ibáñez de Aldecoa AL, Zafra O, González-Pastor JE. Mechanisms and Regulation of Extracellular DNA Release and Its Biological Roles in Microbial Communities. Front Microbiol 2017; 8:1390. [PMID: 28798731 PMCID: PMC5527159 DOI: 10.3389/fmicb.2017.01390] [Citation(s) in RCA: 177] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 07/10/2017] [Indexed: 12/14/2022] Open
Abstract
The capacity to release genetic material into the extracellular medium has been reported in cultures of numerous species of bacteria, archaea, and fungi, and also in the context of multicellular microbial communities such as biofilms. Moreover, extracellular DNA (eDNA) of microbial origin is widespread in natural aquatic and terrestrial environments. Different specific mechanisms are involved in eDNA release, such as autolysis and active secretion, as well as through its association with membrane vesicles. It is noteworthy that in microorganisms, in which DNA release has been studied in detail, the production of eDNA is coordinated by the population when it reaches a certain cell density, and is induced in a subpopulation in response to the accumulation of quorum sensing signals. Interestingly, in several bacteria there is also a relationship between eDNA release and the development of natural competence (the ability to take up DNA from the environment), which is also controlled by quorum sensing. Then, what is the biological function of eDNA? A common biological role has not been proposed, since different functions have been reported depending on the microorganism. However, it seems to be important in biofilm formation, can be used as a nutrient source, and could be involved in DNA damage repair and gene transfer. This review covers several aspects of eDNA research: (i) its occurrence and distribution in natural environments, (ii) the mechanisms and regulation of its release in cultured microorganisms, and (iii) its biological roles. In addition, we propose that eDNA release could be considered a social behavior, based on its quorum sensing-dependent regulation and on the described functions of eDNA in the context of microbial communities.
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Affiliation(s)
- Alejandra L Ibáñez de Aldecoa
- Laboratory of Molecular Adaptation, Department of Molecular Evolution, Centro de Astrobiología (Consejo Superior de Investigaciones Científicas/Instituto Nacional de Técnica Aeroespacial)Madrid, Spain
| | - Olga Zafra
- Experimental Sciences Faculty, Francisco de Vitoria UniversityMadrid, Spain
| | - José E González-Pastor
- Laboratory of Molecular Adaptation, Department of Molecular Evolution, Centro de Astrobiología (Consejo Superior de Investigaciones Científicas/Instituto Nacional de Técnica Aeroespacial)Madrid, Spain
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24
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Barenkamp SJ, Chonmaitree T, Hakansson AP, Heikkinen T, King S, Nokso-Koivisto J, Novotny LA, Patel JA, Pettigrew M, Swords WE. Panel 4: Report of the Microbiology Panel. Otolaryngol Head Neck Surg 2017; 156:S51-S62. [PMID: 28372529 PMCID: PMC5490388 DOI: 10.1177/0194599816639028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/24/2016] [Indexed: 12/12/2022]
Abstract
Objective To perform a comprehensive review of the literature from July 2011 until June 2015 on the virology and bacteriology of otitis media in children. Data Sources PubMed database of the National Library of Medicine. Review Methods Two subpanels comprising experts in the virology and bacteriology of otitis media were created. Each panel reviewed the relevant literature in the fields of virology and bacteriology and generated draft reviews. These initial reviews were distributed to all panel members prior to meeting together at the Post-symposium Research Conference of the 18th International Symposium on Recent Advances in Otitis Media, National Harbor, Maryland, in June 2015. A final draft was created, circulated, and approved by all panel members. Conclusions Excellent progress has been made in the past 4 years in advancing our understanding of the microbiology of otitis media. Numerous advances were made in basic laboratory studies, in animal models of otitis media, in better understanding the epidemiology of disease, and in clinical practice. Implications for Practice (1) Many viruses cause acute otitis media without bacterial coinfection, and such cases do not require antibiotic treatment. (2) When respiratory syncytial virus, metapneumovirus, and influenza virus peak in the community, practitioners can expect to see an increase in clinical otitis media cases. (3) Biomarkers that predict which children with upper respiratory tract infections will develop otitis media may be available in the future. (4) Compounds that target newly identified bacterial virulence determinants may be available as future treatment options for children with otitis media.
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Affiliation(s)
- Stephen J. Barenkamp
- Department of Pediatrics, St Louis University School of Medicine, St Louis, Missouri, USA
| | - Tasnee Chonmaitree
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Terho Heikkinen
- Department of Pediatrics, University of Turku and Turku University Hospital, Turku, Finland
| | - Samantha King
- The Research Institute at Nationwide Children’s Hospital and Ohio State University, Columbus, Ohio, USA
| | - Johanna Nokso-Koivisto
- Department of Otorhinolaryngology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Laura A. Novotny
- The Research Institute at Nationwide Children’s Hospital and Ohio State University, Columbus, Ohio, USA
| | - Janak A. Patel
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Melinda Pettigrew
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - W. Edward Swords
- Department of Microbiology and Immunology, Wake Forest University, Winston-Salem, North Carolina, USA
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25
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Chao Y, Bergenfelz C, Håkansson AP. In Vitro and In Vivo Biofilm Formation by Pathogenic Streptococci. Methods Mol Biol 2017; 1535:285-299. [PMID: 27914087 DOI: 10.1007/978-1-4939-6673-8_19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This manuscript presents novel approaches to grow and evaluate Streptococcal biofilm formation using the human respiratory pathogen Streptococcus pneumoniae (the pneumococcus) as the main model organism on biological surfaces in vitro and in vivo. Most biofilm models are based on growth on abiotic surfaces, which is relevant for many pathogens whose growth on surfaces or medical devices is a major cause of disease transmission and infections, especially in hospital environments. However, most infections with commensal organisms require biofilm formation on biological surfaces in the host at the site of colonization or infection. In vitro model systems incorporating biological components from the host and taking into account the host environment of the infectious site are not well described.In a series of publications, we have shown that S. pneumoniae form complex biofilms in the nasopharynx of mice and have devised methodology to evaluate the biofilm structure and function in this environment. We have also been able to recapitulate this biofilm phenotype in vitro by incorporating crucial factors associated with the host environment. Although the protocols presented in this manuscript are focused on S. pneumoniae, the same methodology can and has been used for other Streptococcal species that form biofilms on mucosal surfaces.
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Affiliation(s)
- Yashuan Chao
- Division of Experimental Infection Medicine, Department of Translational Medicine, Wallenberg Laboratory, Lund University, 53 Inga Marie Nilsson Street, 20502, Malmö, Sweden
| | - Caroline Bergenfelz
- Division of Experimental Infection Medicine, Department of Translational Medicine, Wallenberg Laboratory, Lund University, 53 Inga Marie Nilsson Street, 20502, Malmö, Sweden
| | - Anders P Håkansson
- Division of Experimental Infection Medicine, Department of Translational Medicine, Wallenberg Laboratory, Lund University, 53 Inga Marie Nilsson Street, 20502, Malmö, Sweden.
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26
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Jahns AC, Eilers H, Alexeyev OA. Transcriptomic analysis of Propionibacterium acnes biofilms in vitro. Anaerobe 2016; 42:111-118. [DOI: 10.1016/j.anaerobe.2016.10.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/05/2016] [Accepted: 10/06/2016] [Indexed: 10/20/2022]
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27
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Domenech M, Pedrero-Vega E, Prieto A, García E. Evidence of the presence of nucleic acids and β-glucan in the matrix of non-typeable Haemophilus influenzae in vitro biofilms. Sci Rep 2016; 6:36424. [PMID: 27805043 PMCID: PMC5090351 DOI: 10.1038/srep36424] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/14/2016] [Indexed: 12/21/2022] Open
Abstract
Non-typeable Haemophilus influenzae (NTHi) is a Gram-negative bacterium that frequently colonizes the human nasopharynx; it is a common cause of chronic and recurrent otitis media in children and of exacerbations of chronic obstructive pulmonary disease. To date, no exopolysaccharide clearly contributing to NTHi biofilms has been identified. Consequently, there is some debate as to whether NTHi forms biofilms during colonization and infection. The present work shows that NTHi can form biofilms in vitro, producing an extracellular matrix composed of proteins, nucleic acids, and a β-glucan. Extracellular DNA, visualized by immunostaining and using fluorochromes, is an important component of this matrix and appears to be essential in biofilm maintenance. Extracellular RNA appears to be required only in the first steps of biofilm formation. Evidence of a matrix polysaccharide was obtained by staining with Calcofluor white M2R and by disaggregating biofilms with cellulase. Using strain 54997, residues of Glcp(1→4) in the NTHi biofilm were confirmed by gas-liquid chromatography-mass spectrometry. Evidence that N-acetyl-L-cysteine shows notable killing activity towards in vitro NTHi biofilm-forming bacteria is also provided.
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Affiliation(s)
- Mirian Domenech
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Monforte de Lemos 3–5, 28029 Madrid, Spain
| | - Elena Pedrero-Vega
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Alicia Prieto
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Ernesto García
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Monforte de Lemos 3–5, 28029 Madrid, Spain
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The BR domain of PsrP interacts with extracellular DNA to promote bacterial aggregation; structural insights into pneumococcal biofilm formation. Sci Rep 2016; 6:32371. [PMID: 27582320 PMCID: PMC5007671 DOI: 10.1038/srep32371] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/05/2016] [Indexed: 12/21/2022] Open
Abstract
The major human pathogen Streptococcus pneumoniae is a leading cause of disease and death worldwide. Pneumococcal biofilm formation within the nasopharynx leads to long-term colonization and persistence within the host. We have previously demonstrated that the capsular surface-associated pneumococcal serine rich repeat protein (PsrP), key factor for biofilm formation, binds to keratin-10 (KRT10) through its microbial surface component recognizing adhesive matrix molecule (MSCRAMM)-related globular binding region domain (BR187–385). Here, we show that BR187–385 also binds to DNA, as demonstrated by electrophoretic mobility shift assays and size exclusion chromatography. Further, heterologous expression of BR187–378 or the longer BR120–378 construct on the surface of a Gram-positive model host bacterium resulted in the formation of cellular aggregates that was significantly enhanced in the presence of DNA. Crystal structure analyses revealed the formation of BR187–385 homo-dimers via an intermolecular β-sheet, resulting in a positively charged concave surface, shaped to accommodate the acidic helical DNA structure. Furthermore, small angle X-ray scattering and circular dichroism studies indicate that the aggregate-enhancing N-terminal region of BR120–166 adopts an extended, non-globular structure. Altogether, our results suggest that PsrP adheres to extracellular DNA in the biofilm matrix and thus promotes pneumococcal biofilm formation.
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Substrate recognition and catalysis by LytB, a pneumococcal peptidoglycan hydrolase involved in virulence. Sci Rep 2015; 5:16198. [PMID: 26537571 PMCID: PMC4633669 DOI: 10.1038/srep16198] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/12/2015] [Indexed: 12/21/2022] Open
Abstract
Streptococcus pneumoniae is a major cause of life-threatening diseases worldwide. Here we provide an in-depth functional characterization of LytB, the peptidoglycan hydrolase responsible for physical separation of daughter cells. Identified herein as an N-acetylglucosaminidase, LytB is involved also in colonization and invasion of the nasopharynx, biofilm formation and evasion of host immunity as previously demonstrated. We have shown that LytB cleaves the GlcNAc-β-(1,4)-MurNAc glycosidic bond of peptidoglycan building units. The hydrolysis occurs at sites with fully acetylated GlcNAc moieties, with preference for uncross-linked muropeptides. The necessity of GlcN acetylation and the presence of a single acidic moiety (Glu585) essential for catalysis strongly suggest a substrate-assisted mechanism with anchimeric assistance of the acetamido group of GlcNAc moieties. Additionally, modelling of the catalytic region bound to a hexasaccharide tripentapeptide provided insights into substrate-binding subsites and peptidoglycan recognition. Besides, cell-wall digestion products and solubilisation rates might indicate a tight control of LytB activity to prevent unrestrained breakdown of the cell wall. Choline-independent localization at the poles of the cell, mediated by the choline-binding domain, peptidoglycan modification, and choline-mediated (lipo)teichoic-acid attachment contribute to the high selectivity of LytB. Moreover, so far unknown chitin hydrolase and glycosyltransferase activities were detected using GlcNAc oligomers as substrate.
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Mayanskiy AN, Chebotar IV, Lazareva AV, Mayanskiy NA. Biofilm formation by Streptococcus pneumoniae. MOLECULAR GENETICS MICROBIOLOGY AND VIROLOGY 2015. [DOI: 10.3103/s0891416815030040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Domenech M, Ruiz S, Moscoso M, García E. In vitro biofilm development of Streptococcus pneumoniae and formation of choline-binding protein-DNA complexes. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:715-727. [PMID: 25950767 DOI: 10.1111/1758-2229.12295] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 04/08/2015] [Indexed: 06/04/2023]
Abstract
Extracellular deoxyribonucleic acid (eDNA) is an essential component of bacterial biofilm matrices, and is required in their formation and maintenance. Extracellular DNA binds to exopolysaccharides or extracellular proteins, affording biofilms greater structural integrity. Recently, we reported evidence of intercellular eDNA-LytC complexes in pneumococcal biofilms. The LytC lysozyme is a member of the choline-binding family of proteins (CBPs) located on the pneumococcal surface. The present work shows that other CBPs, i.e. LytA, LytB, Pce, PspC and CbpF, which have a pI between 5 and 6, can bind DNA in vitro. This process requires the presence of divalent cations other than Mg(2+). This DNA binding capacity of CBPs appears to be independent of their enzymatic activity and, at least in the case of LytA, does not require the choline-binding domain characteristic of CBPs. Positively charged, surface-exposed, 25 amino acid-long peptides derived from the catalytic domain of LytB, were also found capable of DNA binding through electrostatic interactions. Confocal laser scanning microcopy revealed the existence of cell-associated LytB-eDNA complexes in Streptococcus pneumoniae biofilms. These and other findings suggest that these surface-located proteins of S. pneumoniae could play roles of varying importance in the colonization and/or invasion of human host where different environmental conditions exist.
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Affiliation(s)
- Mirian Domenech
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Susana Ruiz
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Miriam Moscoso
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
| | - Ernesto García
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, 28040, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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Minimal Peptidoglycan (PG) Turnover in Wild-Type and PG Hydrolase and Cell Division Mutants of Streptococcus pneumoniae D39 Growing Planktonically and in Host-Relevant Biofilms. J Bacteriol 2015; 197:3472-85. [PMID: 26303829 DOI: 10.1128/jb.00541-15] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 08/15/2015] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED We determined whether there is turnover of the peptidoglycan (PG) cell wall of the ovococcus bacterial pathogen Streptococcus pneumoniae (pneumococcus). Pulse-chase experiments on serotype 2 strain D39 radiolabeled with N-acetylglucosamine revealed little turnover and release of PG breakdown products during growth compared to published reports of PG turnover in Bacillus subtilis. PG dynamics were visualized directly by long-pulse-chase-new-labeling experiments using two colors of fluorescent d-amino acid (FDAA) probes to microscopically detect regions of new PG synthesis. Consistent with minimal PG turnover, hemispherical regions of stable "old" PG persisted in D39 and TIGR4 (serotype 4) cells grown in rich brain heart infusion broth, in D39 cells grown in chemically defined medium containing glucose or galactose as the carbon source, and in D39 cells grown as biofilms on a layer of fixed human epithelial cells. In contrast, B. subtilis exhibited rapid sidewall PG turnover in similar FDAA-labeling experiments. High-performance liquid chromatography (HPLC) analysis of biochemically released peptides from S. pneumoniae PG validated that FDAAs incorporated at low levels into pentamer PG peptides and did not change the overall composition of PG peptides. PG dynamics were also visualized in mutants lacking PG hydrolases that mediate PG remodeling, cell separation, or autolysis and in cells lacking the MapZ and DivIVA division regulators. In all cases, hemispheres of stable old PG were maintained. In PG hydrolase mutants exhibiting aberrant division plane placement, FDAA labeling revealed patches of inert PG at turns and bulge points. We conclude that growing S. pneumoniae cells exhibit minimal PG turnover compared to the PG turnover in rod-shaped cells. IMPORTANCE PG cell walls are unique to eubacteria, and many bacterial species turn over and recycle their PG during growth, stress, colonization, and virulence. Consequently, PG breakdown products serve as signals for bacteria to induce antibiotic resistance and as activators of innate immune responses. S. pneumoniae is a commensal bacterium that colonizes the human nasopharynx and opportunistically causes serious respiratory and invasive diseases. The results presented here demonstrate a distinct demarcation between regions of old PG and regions of new PG synthesis and minimal turnover of PG in S. pneumoniae cells growing in culture or in host-relevant biofilms. These findings suggest that S. pneumoniae minimizes the release of PG breakdown products by turnover, which may contribute to evasion of the innate immune system.
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Vandevelde NM, Tulkens PM, Muccioli GG, Van Bambeke F. Modulation of the activity of moxifloxacin and solithromycin in an in vitro pharmacodynamic model of Streptococcus pneumoniae naive and induced biofilms. J Antimicrob Chemother 2015; 70:1713-26. [PMID: 25712316 DOI: 10.1093/jac/dkv032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 01/21/2015] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES Bacterial biofilms developing in the bronchial tree of patients experiencing acute exacerbations of chronic bronchitis (AECBs) are suggested to cause relapses and recurrences of the disease because the matrix barrier impairs antibiotic access to the offending organisms. We examined whether bronchodilators could modulate pneumococcal biofilm development and antibiotic action using an in vitro model. METHODS Streptococcus pneumoniae strains from patients hospitalized for AECBs and two reference strains (ATCC 49619 and R6) were screened for biofilm formation (multi-well plates; 2-11 days of growth). Ipratropium and salbutamol (alone or in combination) were added at concentrations of 1.45 and 7.25 mg/L, respectively (mimicking those in the bronchial tree), and their effects were measured on biofilm formation and modulation of the activity of antibiotics [full antibiotic concentration-dependent effects (pharmacodynamic model)] with a focus on moxifloxacin and solithromycin. Bacterial viability and biomass were measured by the reduction of resazurin and crystal violet staining, respectively. Release of sialic acid (from biofilm) and neuraminidase activity were measured using enzymatic and HPLC-MS detection of sialic acid. RESULTS All clinical isolates produced biofilms, but with fast disassembly if from patients who had received muscarinic antagonists. Ipratropium caused: (i) reduced biomass formation and faster biofilm disassembly with free sialic acid release; and (ii) a marked improvement of antibiotic activity (bacterial killing and biomass reduction). Salbutamol stimulated neuraminidase activity associated with improved antibiotic killing activity (reversed by zanamivir) but modest biomass reduction. CONCLUSIONS Ipratropium and, to a lesser extent, salbutamol may cooperate with antibiotics for bacterial clearance and disassembly of pneumococcal biofilms.
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Affiliation(s)
- Nathalie M Vandevelde
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Paul M Tulkens
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Giulio G Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
| | - Françoise Van Bambeke
- Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium
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Comparative transcriptome analysis reveals that lactose acts as an inducer and provides proper carbon sources for enhancing exopolysaccharide yield in the deep-sea bacterium Zunongwangia profunda SM-A87. PLoS One 2015; 10:e0115998. [PMID: 25679965 PMCID: PMC4332637 DOI: 10.1371/journal.pone.0115998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 12/03/2014] [Indexed: 11/23/2022] Open
Abstract
Many marine bacteria secrete exopolysaccharides (EPSs) that have important ecological and physiological functions. Numerous nutritional and environmental factors influence bacterial EPS production. However, the regulatory mechanisms of EPS production are poorly understood. The deep-sea Bacteroidetes bacterium Zunongwangia profunda SM-A87 can produce high quantities of EPS, and its EPS production is enhanced significantly by lactose. Here, we studied the reasons behind the significant advantage that lactose has over other carbon sources in EPS production in SM-A87. RNA-seq technologies were used to study lactose-regulated genes in SM-A87. The expression level of genes within the EPS gene cluster was up-regulated when lactose was added. Supplement of lactose also influenced the expression of genes located outside the EPS gene cluster that are also involved in EPS biosynthesis. The major glycosyl components of SM-A87 EPS are mannose, glucose and galactose. Genomic metabolic pathway analyses showed that the EPS precursor GDP-mannose can be synthesized from glucose, while the precursor UDP-glucose must be synthesized from galactose. Lactose can provide glucose and galactose simultaneously and prevent glucose inhibition. Lactose can also greatly stimulate the growth of SM-A87. Taken together, lactose acts not only as an inducer but also as a carbohydrate source for EPS production. This research broadens our knowledge of the regulation of EPS production in marine bacteria.
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Friedman M. Chemistry and multibeneficial bioactivities of carvacrol (4-isopropyl-2-methylphenol), a component of essential oils produced by aromatic plants and spices. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:7652-7670. [PMID: 25058878 DOI: 10.1021/jf5023862] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Aromatic plants produce organic compounds that may be involved in the defense of plants against phytopathogenic insects, bacteria, fungi, and viruses. One of these compounds, called carvacrol, which is found in high concentrations in essential oils such as oregano, has been reported to exhibit numerous bioactivities in cells and animals. This integrated overview surveys and interprets our present knowledge of the chemistry and analysis of carvacrol and its beneficial bioactivities. These activities include its antioxidative properties in food (e.g., lard, sunflower oil) and in vivo and the inhibition of foodborne and human antibiotic-susceptible and antibiotic-resistant pathogenic bacteria, viruses, pathogenic fungi and parasites, and insects in vitro and in human foods (e.g., apple juice, eggs, leafy greens, meat and poultry products, milk, oysters) and food animal feeds and wastes. Also covered are inhibitions of microbial and fungal toxin production and the anti-inflammatory, analgesic, antiarthritic, antiallergic, anticarcinogenic, antidiabetic, cardioprotective, gastroprotective, hepatoprotective, and neuroprotective properties of carvacrol as well as metabolic, synergistic, and mechanistic aspects. Areas for future research are also suggested. The collated information and suggested research might contribute to a better understanding of agronomical, biosynthetic, chemical, physiological, and cellular mechanisms of the described health-promoting effects of carvacrol, and facilitate and guide further studies needed to optimize the use of carvacrol as a multifunctional food in pure and encapsulated forms, in edible antimicrobial films, and in combination with plant-derived and medical antibiotics to help prevent or treat animal and human diseases.
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Affiliation(s)
- Mendel Friedman
- Western Regional Research Center, Agricultural Research Service , U.S. Department of Agriculture, Albany, California 94710, United States
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Charlebois A, Jacques M, Archambault M. Biofilm formation of Clostridium perfringens and its exposure to low-dose antimicrobials. Front Microbiol 2014; 5:183. [PMID: 24795711 PMCID: PMC4001024 DOI: 10.3389/fmicb.2014.00183] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/03/2014] [Indexed: 01/09/2023] Open
Abstract
Clostridium perfringens is an opportunistic pathogen that can cause food poisoning in humans and various enterotoxemia in animal species. Very little is known on the biofilm of C. perfringens and its exposure to subminimal inhibitory concentrations of antimicrobials. This study was undertaken to address these issues. Most of the C. perfringens human and animal isolates tested in this study were able to form biofilm (230/277). Porcine clinical isolates formed significantly more biofilm than the porcine commensal isolates. A subgroup of clinical and commensal C. perfringens isolates was randomly selected for further characterization. Biofilm was found to protect C. perfringens bacterial cells from exposure to high concentrations of tested antimicrobials. Exposure to low doses of some of these antimicrobials tended to lead to a diminution of the biofilm formed. However, a few isolates showed an increase in biofilm formation when exposed to low doses of tylosin, bacitracin, virginiamycin, and monensin. Six isolates were randomly selected for biofilm analysis using scanning laser confocal microscopy. Of those, four produced more biofilm in presence of low doses of bacitracin whereas biofilms formed without bacitracin were thinner and less elevated. An increase in the area occupied by bacteria in the biofilm following exposure to low doses of bacitracin was also observed in the majority of isolates. Morphology examination revealed flat biofilms with the exception of one isolate that demonstrated a mushroom-like biofilm. Matrix composition analysis showed the presence of proteins, beta-1,4 linked polysaccharides and extracellular DNA, but no poly-beta-1,6-N-acetyl-D-glucosamine. This study brings new information on the biofilm produced by C. perfringens and its exposure to low doses of antimicrobials.
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Affiliation(s)
- Audrey Charlebois
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, QC, Canada ; Centre de Recherche en Infectiologie Porcine et Avicole, Université de Montréal Saint-Hyacinthe, QC, Canada
| | - Mario Jacques
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, QC, Canada ; Centre de Recherche en Infectiologie Porcine et Avicole, Université de Montréal Saint-Hyacinthe, QC, Canada
| | - Marie Archambault
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, QC, Canada ; Centre de Recherche en Infectiologie Porcine et Avicole, Université de Montréal Saint-Hyacinthe, QC, Canada
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Streptococcus pneumoniae biofilm formation is strain dependent, multifactorial, and associated with reduced invasiveness and immunoreactivity during colonization. mBio 2013; 4:e00745-13. [PMID: 24129258 PMCID: PMC3812715 DOI: 10.1128/mbio.00745-13] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
UNLABELLED Biofilms are thought to play an important role during colonization of the nasopharynx by Streptococcus pneumoniae, yet how they form in vivo and the determinants responsible remain unknown. Using scanning electron microscopy, we show that biofilm aggregates of increasing complexity form on murine nasal septa following intranasal inoculation. These biofilms were highly distinct from in vitro biofilms, as they were discontiguous and appeared to incorporate nonbacterial components such as intact host cells. Biofilms initially formed on the surface of ciliated epithelial cells and, as cells were sloughed off, were found on the basement membrane. The size and number of biofilm aggregates within nasal lavage fluid were digitally quantitated and revealed strain-specific capabilities that loosely correlated with the ability to form robust in vitro biofilms. We tested the ability of isogenic mutants deficient in CbpA, pneumolysin, hydrogen peroxide, LytA, LuxS, CiaR/H, and PsrP to form biofilms within the nasopharynx. This analysis revealed that CiaR/H was absolutely required for colonization, that PsrP and SpxB strongly impacted aggregate formation, and that other determinants affected aggregate morphology in a modest fashion. We determined that mice colonized with ΔpsrP mutants had greater levels of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), IL-1β, and KC in nasal lavage fluid than did mice colonized with wild-type controls. This phenotype correlated with a diminished capacity of biofilm pneumococci to invade host cells in vitro despite enhanced attachment. Our results show that biofilms form during colonization and suggest that they may contribute to persistence through a hyperadhesive, noninvasive state that elicits a dampened cytokine response. IMPORTANCE This work demonstrates the first temporal characterization of Streptococcus pneumoniae biofilm formation in vivo. Our results show that the morphology of biofilms formed by both invasive and noninvasive clinical isolates in vivo is distinct from that of formed biofilms in vitro, yet propensity to form biofilms in vivo loosely correlates with the degree of in vitro biofilm formation on a microtiter plate. We show that host components, including intact host cells, influence the formation of in vivo structures. We also found that efficient biofilm formation in vivo requires multiple bacterial determinants. While some factors are essential for in vivo biofilm formation (CiaRH, PsrP, and SpxB), other factors are less critical (CbpA, LytA, LuxS, and pneumolysin). In comparison to their planktonic counterparts, biofilm pneumococci are hyperadhesive but less invasive and elicit a weaker proinflammatory cytokine response. These findings give insight into the requirements for and potential role of biofilms during prolonged asymptomatic colonization.
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Tikhomirova A, Kidd SP. Haemophilus influenzae and Streptococcus pneumoniae: living together in a biofilm. Pathog Dis 2013; 69:114-26. [PMID: 23913525 DOI: 10.1111/2049-632x.12073] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/25/2013] [Accepted: 07/25/2013] [Indexed: 11/27/2022] Open
Abstract
Streptococcus pneumoniae and Haemophilus influenzae are both commensals of the human nasopharynx with an ability to migrate to other niches within the human body to cause various diseases of the upper respiratory tract such as pneumonia, otitis media and bronchitis. They have long been detected together in a multispecies biofilm in infected tissue. However, an understanding of their interplay is a recent field of study, and while over recent years, there has been research that has identified many specific elements important in these biofilms, to date, it remains questionable whether the relationship between H. influenzae and S. pneumoniae is competitive or cooperative. Additionally, the factors that govern the nature of the interspecies interaction are still undefined. This review aims to collate the information that has emerged on the cocolonization and co-infection by S. pneumoniae and nontypeable H. influenzae (NTHi) and their formation of a multispecies biofilm.
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Affiliation(s)
- Alexandra Tikhomirova
- Research Centre for Infectious Disease, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
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Jakubovics NS, Shields RC, Rajarajan N, Burgess JG. Life after death: the critical role of extracellular DNA in microbial biofilms. Lett Appl Microbiol 2013; 57:467-75. [PMID: 23848166 DOI: 10.1111/lam.12134] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 06/25/2013] [Accepted: 07/10/2013] [Indexed: 01/24/2023]
Abstract
The death and lysis of microbial cells leads to the release of cytoplasmic contents, many of which are rapidly degraded by enzymes. However, some macromolecules survive intact and find new functions in the extracellular environment. There is now strong evidence that DNA released from cells during lysis, or sometimes by active secretion, becomes a key component of the macromolecular scaffold in many different biofilms. Enzymatic degradation of extracellular DNA can weaken the biofilm structure and release microbial cells from the surface. Many bacteria produce extracellular deoxyribonuclease (DNase) enzymes that are apparently tightly regulated to avoid excessive degradation of the biofilm matrix. Interfering with these control mechanisms, or adding exogenous DNases, could prove a potent strategy for controlling biofilm growth.
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Affiliation(s)
- N S Jakubovics
- Oral Biology, School of Dental Sciences, Newcastle University, Newcastle upon Tyne, UK
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Expression of Streptococcus pneumoniae Virulence-Related Genes in the Nasopharynx of Healthy Children. PLoS One 2013; 8:e67147. [PMID: 23825636 PMCID: PMC3688971 DOI: 10.1371/journal.pone.0067147] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 05/13/2013] [Indexed: 11/19/2022] Open
Abstract
Colonization and persistence in the human nasopharynx are prerequisites for Streptococcus pneumoniae disease and carriage acquisition, which normally occurs during early childhood. Animal models and in vitro studies (i.e. cell adhesion and cell cytotoxicity assays) have revealed a number of colonization and virulence factors, as well as regulators, implicated in nasopharyngeal colonization and pathogenesis. Expression of genes encoding these factors has never been studied in the human nasopharynx. Therefore, this study analyzed expression of S. pneumoniae virulence-related genes in human nasopharyngeal samples. Our experiments first demonstrate that a density of ≥10(4) CFU/ml of S. pneumoniae cells in the nasopharynx provides enough DNA and RNA to amplify the lytA gene by conventional PCR and to detect the lytA message, respectively. A panel of 21 primers that amplified S. pneumoniae sequences was designed, and their specificity for S. pneumoniae sequences was analyzed in silico and validated against 20 related strains inhabitants of the human upper respiratory tract. These primers were utilized in molecular reactions to find out that all samples contained the genes ply, pavA, lytC, lytA, comD, codY, and mgrA, whereas nanA, nanB, pspA, and rrgB were present in ∼91-98% of the samples. Gene expression studies of these 11 targets revealed that lytC, lytA, pavA and comD were the most highly expressed pneumococcal genes in the nasopharynx whereas the rest showed a moderate to low level of expression. This is the first study to evaluate expression of virulence- and, colonization-related genes in the nasopharynx of healthy children and establishes the foundation for future gene expression studies during human pneumococcal disease.
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Biofilm formation avoids complement immunity and phagocytosis of Streptococcus pneumoniae. Infect Immun 2013; 81:2606-15. [PMID: 23649097 DOI: 10.1128/iai.00491-13] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Streptococcus pneumoniae is a frequent member of the microbiota of the human nasopharynx. Colonization of the nasopharyngeal tract is a first and necessary step in the infectious process and often involves the formation of sessile microbial communities by this human pathogen. The ability to grow and persist as biofilms is an advantage for many microorganisms, because biofilm-grown bacteria show reduced susceptibility to antimicrobial agents and hinder recognition by the immune system. The extent of host protection against biofilm-related pneumococcal disease has not been determined yet. Using pneumococcal strains growing as planktonic cultures or as biofilms, we have investigated the recognition of S. pneumoniae by the complement system and its interactions with human neutrophils. Deposition of C3b, the key complement component, was impaired on S. pneumoniae biofilms. In addition, binding of C-reactive protein and the complement component C1q to the pneumococcal surface was reduced in biofilm bacteria, demonstrating that pneumococcal biofilms avoid the activation of the classical complement pathway. In addition, recruitment of factor H, the downregulator of the alternative pathway, was enhanced by S. pneumoniae growing as biofilms. Our results also show that biofilm formation diverts the alternative complement pathway activation by a PspC-mediated mechanism. Furthermore, phagocytosis of pneumococcal biofilms was also impaired. The present study confirms that biofilm formation in S. pneumoniae is an efficient means of evading both the classical and the PspC-dependent alternative complement pathways the host immune system.
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Quorum-sensing systems LuxS/autoinducer 2 and Com regulate Streptococcus pneumoniae biofilms in a bioreactor with living cultures of human respiratory cells. Infect Immun 2013; 81:1341-53. [PMID: 23403556 DOI: 10.1128/iai.01096-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Streptococcus pneumoniae forms organized biofilms in the human upper respiratory tract that may play an essential role in both persistence and acute respiratory infection. However, the production and regulation of biofilms on human cells is not yet fully understood. In this work, we developed a bioreactor with living cultures of human respiratory epithelial cells (HREC) and a continuous flow of nutrients, mimicking the microenvironment of the human respiratory epithelium, to study the production and regulation of S. pneumoniae biofilms (SPB). SPB were also produced under static conditions on immobilized HREC. Our experiments demonstrated that the biomass of SPB increased significantly when grown on HREC compared to the amount on abiotic surfaces. Additionally, pneumococcal strains produced more early biofilms on lung cells than on pharyngeal cells. Utilizing the bioreactor or immobilized human cells, the production of early SPB was found to be regulated by two quorum-sensing systems, Com and LuxS/AI-2, since a mutation in either comC or luxS rendered the pneumococcus unable to produce early biofilms on HREC. Interestingly, while LuxS/autoinducer 2 (AI-2) regulated biofilms on both HREC and abiotic surfaces, Com control was specific for those structures produced on HREC. The biofilm phenotypes of strain D39-derivative ΔcomC and ΔluxS QS mutants were reversed by genetic complementation. Of note, SPB formed on immobilized HREC and incubated under static conditions were completely lysed 24 h postinoculation. Biofilm lysis was also regulated by the Com and LuxS/AI-2 quorum-sensing systems.
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Community surveillance enhances Pseudomonas aeruginosa virulence during polymicrobial infection. Proc Natl Acad Sci U S A 2012; 110:1059-64. [PMID: 23277552 DOI: 10.1073/pnas.1214550110] [Citation(s) in RCA: 230] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Most infections result from colonization by more than one microbe. Within such polymicrobial infections, microbes often display synergistic interactions that result in increased disease severity. Although many clinical studies have documented the occurrence of synergy in polymicrobial infections, little is known about the underlying molecular mechanisms. A prominent pathogen in many polymicrobial infections is Pseudomonas aeruginosa, a Gram-negative bacterium that displays enhanced virulence during coculture with Gram-positive bacteria. In this study we discovered that during coinfection, P. aeruginosa uses peptidoglycan shed by Gram-positive bacteria as a cue to stimulate production of multiple extracellular factors that possess lytic activity against prokaryotic and eukaryotic cells. Consequently, P. aeruginosa displays enhanced virulence in a Drosophila model of infection when cocultured with Gram-positive bacteria. Inactivation of a gene (PA0601) required for peptidoglycan sensing mitigated this phenotype. Using Drosophila and murine models of infection, we also show that peptidoglycan sensing results in P. aeruginosa-mediated reduction in the Gram-positive flora in the infection site. Our data suggest that P. aeruginosa has evolved a mechanism to survey the microbial community and respond to Gram-positive produced peptidoglycan through production of antimicrobials and toxins that not only modify the composition of the community but also enhance host killing. Additionally, our results suggest that therapeutic strategies targeting Gram-positive bacteria might be a viable approach for reducing the severity of P. aeruginosa polymicrobial infections.
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Shak JR, Vidal JE, Klugman KP. Influence of bacterial interactions on pneumococcal colonization of the nasopharynx. Trends Microbiol 2012; 21:129-35. [PMID: 23273566 DOI: 10.1016/j.tim.2012.11.005] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/13/2012] [Accepted: 11/19/2012] [Indexed: 12/11/2022]
Abstract
Streptococcus pneumoniae (the pneumococcus) is a common commensal inhabitant of the nasopharynx and a frequent etiologic agent in serious diseases such as pneumonia, otitis media, bacteremia, and meningitis. Multiple pneumococcal strains can colonize the nasopharynx, which is also home to many other bacterial species. Intraspecies and interspecies interactions influence pneumococcal carriage in important ways. Co-colonization by two or more pneumococcal strains has implications for vaccine serotype replacement, carriage detection, and pneumonia diagnostics. Interactions between the pneumococcus and other bacterial species alter carriage prevalence, modulate virulence, and affect biofilm formation. By examining these interactions, this review highlights how the bacterial ecosystem of the nasopharynx changes the nature and course of pneumococcal carriage.
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Affiliation(s)
- Joshua R Shak
- Molecules to Mankind Program and Graduate Program in Population Biology, Ecology, and Evolution, Laney Graduate School, Emory University, Atlanta, GA 30322, USA
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