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Sun Y, Wu M, Xie S, Zang J, Wang X, Yang Y, Li C, Wang J. Homogenization of bacterial plastisphere community in soil: a continental-scale microcosm study. ISME COMMUNICATIONS 2024; 4:ycad012. [PMID: 38328447 PMCID: PMC10848224 DOI: 10.1093/ismeco/ycad012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/14/2023] [Accepted: 12/19/2023] [Indexed: 02/09/2024]
Abstract
Microplastics alter niches of soil microbiota by providing trillions of artificial microhabitats, termed the "plastisphere." Because of the ever-increasing accumulation of microplastics in ecosystems, it is urgent to understand the ecology of microbes associated with the plastisphere. Here, we present a continental-scale study of the bacterial plastisphere on polyethylene microplastics compared with adjacent soil communities across 99 sites collected from across China through microcosm experiments. In comparison with the soil bacterial communities, we found that plastispheres had a greater proportion of Actinomycetota and Bacillota, but lower proportions of Pseudomonadota, Acidobacteriota, Gemmatimonadota, and Bacteroidota. The spatial dispersion and the dissimilarity among plastisphere communities were less variable than those among the soil bacterial communities, suggesting highly homogenized bacterial communities on microplastics. The relative importance of homogeneous selection in plastispheres was greater than that in soil samples, possibly because of the more uniform properties of polyethylene microplastics compared with the surrounding soil. Importantly, we found that the degree to which plastisphere and soil bacterial communities differed was negatively correlated with the soil pH and carbon content and positively related to the mean annual temperature of sampling sites. Our work provides a more comprehensive continental-scale perspective on the microbial communities that form in the plastisphere and highlights the potential impacts of microplastics on the maintenance of microbial biodiversity and ecosystem functioning.
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Affiliation(s)
- Yuanze Sun
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Mochen Wu
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Siyuan Xie
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Jingxi Zang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Xiang Wang
- Key Laboratory of Arable Land Conservation (North China), Department of Soil and Water Science, College of Land Science and Technology, China Agricultural University, Beijing 100193, China
| | - Yuyi Yang
- Key Laboratory of Aquatic Botany and Watershed Ecology Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430070, China
| | - Changchao Li
- State Key Laboratory of Marine Pollution, Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Yuk Choi Road, Kowloon, Hong Kong 999077, China
| | - Jie Wang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
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2
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Witsø IL, Basson A, Vinje H, Llarena AK, Bringas CS, Aspholm M, Wasteson Y, Myrmel M. Freshwater plastispheres as a vector for foodborne bacteria and viruses. Environ Microbiol 2023; 25:2864-2881. [PMID: 37964725 DOI: 10.1111/1462-2920.16536] [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: 04/14/2023] [Accepted: 10/27/2023] [Indexed: 11/16/2023]
Abstract
There is growing evidence that plastic particles can accumulate microorganisms that are pathogenic to humans or animals. In the current study, the composition of the plastispheres that accumulated on polypropylene (PP), polyvinyl chloride (PVC), and high-density polyethylene (HDPE) pieces submerged in a river in the southeast Norway was characterized by 16S rRNA amplicon sequencing. Seasonal and geographical effects on the bacterial composition of the plastisphere were identified, in addition to the detection of potential foodborne pathogenic bacteria and viruses as part of the plastisphere. The diversity and taxonomic composition of the plastispheres were influenced by the number of weeks in the river, the season, and the location. The bacterial diversity differed significantly in the plastisphere from June and September, with a generally higher diversity in June. Also, the community composition of the plastisphere was significantly influenced by the geographical location, while the type of plastic had less impact. Plastics submerged in river water assembled a variety of microorganisms including potentially pathogenic bacteria and viruses (noro- and adenovirus) detected by qPCR. Cultivation methods detected viable bacteria such as Escherichia coli and Listeria monocytogenes. The results highlight the need for additional research on the risk of contaminating food with plastic particles colonized with human pathogens through irrigation water.
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Affiliation(s)
- Ingun Lund Witsø
- Faculty of Veterinary Medicine, Food Safety Unit, The Norwegian University of Life Sciences, Ås, Norway
| | - Adelle Basson
- Faculty of Veterinary Medicine, Food Safety Unit, The Norwegian University of Life Sciences, Ås, Norway
- Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Hilde Vinje
- Faculty of Chemistry, Biotechnology and Food Science, The Norwegian University of Life Sciences, Ås, Norway
| | - Ann-Katrin Llarena
- Faculty of Veterinary Medicine, Food Safety Unit, The Norwegian University of Life Sciences, Ås, Norway
| | - Carlos Salas Bringas
- Institute for Marine Operations and Civil Engineering, Norwegian University of Science and Technology, Ålesund, Norway
| | - Marina Aspholm
- Faculty of Veterinary Medicine, Food Safety Unit, The Norwegian University of Life Sciences, Ås, Norway
| | - Yngvild Wasteson
- Faculty of Veterinary Medicine, Food Safety Unit, The Norwegian University of Life Sciences, Ås, Norway
| | - Mette Myrmel
- Faculty of Veterinary Medicine, Virology Unit, The Norwegian University of Life Sciences, Ås, Norway
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Afonso AC, Gomes IB, Saavedra MJ, C Simões L, Simões M. Drinking-water isolated Delftia acidovorans selectively coaggregates with partner bacteria and facilitates multispecies biofilm development. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 875:162646. [PMID: 36889402 DOI: 10.1016/j.scitotenv.2023.162646] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/01/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Coaggregation plays an important role in the development of multispecies biofilms in different environments, often serving as an active bridge between biofilm members and other organisms that, in their absence, would not integrate the sessile structure. The ability of bacteria to coaggregate has been reported for a limited number of species and strains. In this study, 38 bacterial strains isolated from drinking water (DW) were investigated for their ability to coaggregate, in a total of 115 pairs of combinations. Among these isolates, only Delftia acidovorans (strain 005P) showed coaggregating ability. Coaggregation inhibition studies have shown that the interactions mediating D. acidovorans 005P coaggregation were both polysaccharide-protein and protein-protein, depending on the interacting partner bacteria. Dual-species biofilms of D. acidovorans 005P and other DW bacteria were developed to understand the role of coaggregation on biofilm formation. Biofilm formation by Citrobacter freundii and Pseudomonas putida strains highly benefited from the presence of D. acidovorans 005P, apparently due to the production of extracellular molecules/public goods favouring microbial cooperation. This was the first time that the coaggregation capacity of D. acidovorans was demonstrated, highlighting its role in providing a metabolic opportunity for partner bacteria.
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Affiliation(s)
- Ana C Afonso
- ALiCE-LEPABE, Faculty of Engineering, University of Porto, Porto, Portugal; CITAB, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal; CEB-LABBELS, School of Engineering, University of Minho, Braga, Portugal
| | - Inês B Gomes
- ALiCE-LEPABE, Faculty of Engineering, University of Porto, Porto, Portugal
| | | | - Lúcia C Simões
- CEB-LABBELS, School of Engineering, University of Minho, Braga, Portugal
| | - Manuel Simões
- ALiCE-LEPABE, Faculty of Engineering, University of Porto, Porto, Portugal.
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Sun Y, Wu M, Zang J, Du L, Huang M, Chen C, Wang J. Plastisphere microbiome: Methodology, diversity, and functionality. IMETA 2023; 2:e101. [PMID: 38868423 PMCID: PMC10989970 DOI: 10.1002/imt2.101] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/11/2023] [Accepted: 03/16/2023] [Indexed: 06/14/2024]
Abstract
Broad topics of the plastisphere in various environments are reviewed, including its methodologies, diversity, functionality, and outlook.
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Affiliation(s)
- Yuanze Sun
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental SciencesChina Agricultural UniversityBeijingChina
| | - Mochen Wu
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental SciencesChina Agricultural UniversityBeijingChina
| | - Jingxi Zang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental SciencesChina Agricultural UniversityBeijingChina
| | - Linna Du
- College of Advanced Materials EngineeringJiaxing Nanhu UniverisityJiaxingChina
| | - Muke Huang
- China International Engineering Consulting CorporationBeijingChina
| | - Cheng Chen
- China International Engineering Consulting CorporationBeijingChina
| | - Jie Wang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental SciencesChina Agricultural UniversityBeijingChina
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5
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Guo K, Wu N, Li W, Baattrup-Pedersen A, Riis T. Microbial biofilm community dynamics in five lowland streams. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 798:149169. [PMID: 34329932 DOI: 10.1016/j.scitotenv.2021.149169] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/12/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
Stream biofilms are complex aggregates of diverse organism groups that play a vital role in global carbon and nitrogen cycles. Most of the current studies on stream biofilm focus on a limited number of organism groups (e.g., bacteria and algae), and few have included both prokaryote and eukaryote communities simultaneously. In this study, we incubated artificial substrates in five Danish lowland streams exhibiting different hydrological and physico-chemical conditions and explored the dynamics of community composition and diversity of the benthic biofilm, including both prokaryotes and eukaryotes. We found that few phyla in the prokaryote (Gammaproteobacteria and Bacteroidetes) and eukaryote (Cercozoa) communities accounted for over two-thirds of the total abundance at most of the sites. Both prokaryotic and eukaryotic diversity displayed the same temporal patterns, i.e., diversity peaked in July and January. We also found that hydrological and physico-chemical variables significantly explained the variation in the community composition at phylum level for both prokaryotes and eukaryotes. However, a large proportion of variation remained unexplained, which can be ascribed to important but unmeasured variables like light intensity and biological factors such as trophic and non-trophic interactions as revealed by network analysis. Therefore, we suggest that use of a multitrophic level perspective is needed to study biofilm i.e., the "microbial jungles", where high occurrences of trophic and non-trophic interactions are expected.
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Affiliation(s)
- Kun Guo
- Department of Biology, Aarhus University, Ole Worms Allé 1, 8000 Aarhus, Denmark; School of Ecological and Environmental Sciences, East China Normal University, 200241 Shanghai, China
| | - Naicheng Wu
- Department of Geography and Spatial Information Techniques, Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, 315211 Ningbo, China.
| | - Wei Li
- Department of Land Resources and Environmental Sciences, Montana State University, 59717 Bozeman, MT, United States
| | | | - Tenna Riis
- Department of Biology, Aarhus University, Ole Worms Allé 1, 8000 Aarhus, Denmark; WATEC, Aarhus University, Centre for Water Technology, 8000 Aarhus, Denmark
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6
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Zhang H, Xu X, Tan L, Liang Z, Cao R, Wan Q, Xu H, Wang J, Huang T, Wen G. The aggregation of Aspergillus spores and the impact on their inactivation by chlorine-based disinfectants. WATER RESEARCH 2021; 204:117629. [PMID: 34509870 DOI: 10.1016/j.watres.2021.117629] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/17/2021] [Accepted: 08/29/2021] [Indexed: 06/13/2023]
Abstract
The formation of fungal biofilm goes through some different states, including monodisperse state, aggregated state, germinated state, hyphal and biofilm. The aggregation of spores is a primary step of fungal biofilm development in aquatic systems. Previous studies on the inactivation of fungi were mostly performed in the monodisperse state of fungal spores and biofilm state, however, the inactivation of aggregated fungal spores is still unclear. In this study, the aggregated characteristics of fungal spores (Aspergillus fumigatus and Aspergillus flavus) at different pH values were firstly studied, and the inactivation efficiency of fungal spores at different aggregation degree by chlorine-based disinfectants was also clarified. The results showed that the aggregation degree of Aspergillus fumigatus was the highest at pH 9.0 while it was the lowest at pH 5.0. Aggregation between fungal spores was mainly mediated by occasional adhesin-adhesin interactions and electrostatic interactions. Compared with monodisperse spores, fungal spores were more resistant to chlorine-based disinfectants with the increase of spore aggregation degree. The inactivation rate constants of Aspergillus fumigatus at 30% and 63% aggregation degree were 1.5- and 4-folds lower than that of monodisperse spores, respectively. The lower proportion of membrane damage and higher intracellular reactive oxygen species level for aggregated spores than monodisperse spores was observed according to the flow cytometric results after chlorine-based disinfectants treatment. The reasons for the lower inactivation efficiency of aggregated spores are as following: the protection of outer layer spores and signals between aggregates lead to the increase of resistance for aggregated spores. This study is meaningful for the control of the fungal spores at different states in water.
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Affiliation(s)
- Huan Zhang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Xiangqian Xu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Lili Tan
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Zhiting Liang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Ruihua Cao
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Qiqi Wan
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Huining Xu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Jingyi Wang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Tinglin Huang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Gang Wen
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China.
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7
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Yang G, Gong M, Mai L, Zhuang L, Zeng EY. Diversity and structure of microbial biofilms on microplastics in riverine waters of the Pearl River Delta, China. CHEMOSPHERE 2021; 272:129870. [PMID: 33607493 DOI: 10.1016/j.chemosphere.2021.129870] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 06/12/2023]
Abstract
Riverine runoff is a significant transport pathway for microplastics (MPs) discharged from land-based sources to marine environments where MPs accumulate. Knowledge of riverine MP-associated biofilms will improve the understanding of the fate and potential effects of MPs in marine environments. This study aimed to characterize the microbial biofilms colonizing MPs in the riverine water of the Pearl River Delta, China, and identify the seasonal, geographical and environmental influences on MP-associated communities. We sampled MPs and the surrounding surface water from eight outlets in three seasons and analyzed their microbial communities by Illumina sequencing of the 16S rRNA gene libraries. Across all sampling seasons and locations, abundant MP-colonizing taxa belonged to the phylum Proteobacteria, which suggested initial biofilm development on those MPs. The structure and composition of MP-attached microbial communities varied with respect to season and location, and the microbial diversity of the MP-associated biofilm communities decreased in June compared with that in the April and November sampling events. Opportunistic pathogens of the genus Acinetobacter were significantly enriched on the MP surfaces for all sampling events. Among the 15 environmental variables examined, the main drivers of MP-associated biofilm community composition included IC, alkalinity, TOC, TDS, Cl-, NO3-, NO2- and pH. This study provides an insight into the environmental factors that shape microbial biofilm colonization on MPs in estuary environments and a further understanding of the structure, diversity and ecological roles of MP-associated communities.
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Affiliation(s)
- Guiqin Yang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
| | - Mengting Gong
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
| | - Lei Mai
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
| | - Li Zhuang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
| | - Eddy Y Zeng
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
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8
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Afonso AC, Gomes IB, Saavedra MJ, Giaouris E, Simões LC, Simões M. Bacterial coaggregation in aquatic systems. WATER RESEARCH 2021; 196:117037. [PMID: 33751976 DOI: 10.1016/j.watres.2021.117037] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 03/07/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
The establishment of a sessile community is believed to occur in a sequence of steps where genetically distinct bacteria can become attached to partner cells via specific molecules, in a process known as coaggregation. The presence of bacteria with the ability to autoaggregate and coaggregate has been described for diverse aquatic systems, particularly freshwater, drinking water, wastewater, and marine water. In these aquatic systems, coaggregation already demonstrated a role in the development of complex multispecies sessile communities, including biofilms. While specific molecular aspects on coaggregation in aquatic systems remain to be understood, clear evidence exist on the impact of this mechanism in multispecies biofilm resilience and homeostasis. The identification of bridging bacteria among coaggregating consortia has potential to improve the performance of wastewater treatment plants and/or to contribute for the development of strategies to control undesirable biofilms. This study provides a comprehensive analysis on the occurrence and role of bacterial coaggregation in diverse aquatic systems. The potential of this mechanism in water-related biotechnology is further described, with particular emphasis on the role of bridging bacteria.
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Affiliation(s)
- Ana C Afonso
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
| | - Inês B Gomes
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
| | - Maria José Saavedra
- CITAB, Centre for the Research and Technology for Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Ierou Lochou 10 & Makrygianni, Myrina 81400, Lemnos, Greece
| | - Lúcia C Simões
- CEB, Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Manuel Simões
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal.
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9
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Gong M, Yang G, Zhuang L, Zeng EY. Microbial biofilm formation and community structure on low-density polyethylene microparticles in lake water microcosms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 252:94-102. [PMID: 31146243 DOI: 10.1016/j.envpol.2019.05.090] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 05/17/2019] [Accepted: 05/17/2019] [Indexed: 05/20/2023]
Abstract
The occurrence of microplastics (MPs) in the environment has been gaining widespread attention globally. MP-colonizing microorganisms are important links for MPs contamination in various ecosystems, but have not been well understood. To partially address this issue, the present study investigated biofilm formation by microorganisms originating from lake water on low-density polyethylene (LDPE) MPs using a cultivation approach and the surface-related effects on the MP-associated microbial communities using 16S rRNA high-throughput sequencing. With the addition of nonionic surfactants and UV-irradiation pretreatment that changed the surface properties of LDPE MPs, more microorganisms were colonized on LDPE surface. Microbial community analysis indicated that LDPE MPs were primarily colonized by the phyla Proteobacteria, Bacteroidetes and Firmicutes, and the surface roughness and hydrophobicity of MP were important factors shaping the LDPE MP-associated microbial community structure. Half of the top 20 most abundant genera colonizing on LDPE were found to be potential pathogens, e.g., plant pathogens Agrobacterium, nosocomial pathogens Chryseobacterium and fish pathogens Flavobacterium. This study demonstrated rapid bacterial colonization of LDPE MPs in lake water microcosms, the role of MPs as transfer vectors for harmful microorganisms in lake water, and provided a first glimpse into the effect of surface properties on LDPE MP-associated biofilm communities.
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Affiliation(s)
- Mengting Gong
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Guiqin Yang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
| | - Li Zhuang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China.
| | - Eddy Y Zeng
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China
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10
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Oliveira GS, Lopes DRG, Andre C, Silva CC, Baglinière F, Vanetti MCD. Multispecies biofilm formation by the contaminating microbiota in raw milk. BIOFOULING 2019; 35:819-831. [PMID: 31558046 DOI: 10.1080/08927014.2019.1666267] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 08/26/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
Biofilms can be formed on the surfaces of dairy processing equipment and are a potential source of product contamination. This study evaluated the diversity of multispecies biofilms formed on stainless steel (SS) due to the contaminating microbiota in raw milk. Samples of raw milk were used: one was fresh milk and the other maintained in refrigerated bulk tanks for up to 48 h. The mesophilic aerobic contamination was ∼104 CFU ml-1 in fresh milk and 106 CFU ml-1 in bulk milk. SS coupons were kept immersed in the milk at 7 ±2 °C for 10 days, and every two days, the raw milk was changed for samples of the same origin collected on the current day. After incubation for 10 days, sessile cells in the biofilm reached 105 CFU cm-2 in the presence of fresh milk, and 106 CFU cm-2 in the presence of bulk milk. The genetic diversity analysis showed that Gammaproteobacteria and Bacilli predominated in the biofilms throughout the incubation of both milk samples and these biofilms showed a reduction in diversity over time. The main classes of bacteria found in these biofilms have representatives of great importance since many of them have spoilage potential.
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Affiliation(s)
- G S Oliveira
- Department of Microbiology, Federal University of Viçosa, Viçosa, Brazil
| | - D R G Lopes
- Department of Microbiology, Federal University of Viçosa, Viçosa, Brazil
| | - C Andre
- Department of Microbiology, Federal University of Viçosa, Viçosa, Brazil
| | - C C Silva
- Department of Microbiology, Federal University of Viçosa, Viçosa, Brazil
| | - F Baglinière
- Department of Microbiology, Federal University of Viçosa, Viçosa, Brazil
| | - M C D Vanetti
- Department of Microbiology, Federal University of Viçosa, Viçosa, Brazil
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11
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Irankhah S, Abdi Ali A, Mallavarapu M, Soudi MR, Subashchandrabose S, Gharavi S, Ayati B. Ecological role of Acinetobacter calcoaceticus GSN3 in natural biofilm formation and its advantages in bioremediation. BIOFOULING 2019; 35:377-391. [PMID: 31119950 DOI: 10.1080/08927014.2019.1597061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 03/10/2019] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
This study assessed the role of a new Acinetobacter calcoaceticus strain, GSN3, with biofilm-forming and phenol-degrading abilities. Three biofilm reactors were spiked with activated sludge (R1), green fluorescent plasmid (GFP) tagged GSN3 (R2), and their combination (R3). More than 99% phenol removal was achieved during four weeks in R3 while this efficiency was reached after two and four further operational weeks in R2 and R1, respectively. Confocal scanning electron microscopy revealed that GSN3-gfp strains appeared mostly in the deeper layers of the biofilm in R3. After four weeks, almost 7.07 × 107 more attached sludge cells were counted per carrier in R3 in comparison to R1. Additionally, the higher numbers of GSN3-gfp in R2 were unable to increase the efficiency as much as measured in R3. The presence of GSN3-gfp in R3 conveyed advantages, including enhancement of cell immobilization, population diversity, metabolic cooperation and ultimately treatment efficiency.
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Affiliation(s)
- Sahar Irankhah
- a Department of Microbiology, Faculty of Biological Sciences , Alzahra University , Tehran , Iran
- b Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology , University of Newcastle , Callaghan , NSW , Australia
| | - Ahya Abdi Ali
- a Department of Microbiology, Faculty of Biological Sciences , Alzahra University , Tehran , Iran
| | - Megharaj Mallavarapu
- b Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology , University of Newcastle , Callaghan , NSW , Australia
- c CRC CARE, Newcastle University LPO , Callaghan , NSW , Australia
| | - Mohammad Reza Soudi
- a Department of Microbiology, Faculty of Biological Sciences , Alzahra University , Tehran , Iran
| | - Suresh Subashchandrabose
- b Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology , University of Newcastle , Callaghan , NSW , Australia
- c CRC CARE, Newcastle University LPO , Callaghan , NSW , Australia
| | - Sara Gharavi
- d Department of Biotechnology, Faculty of Biological Sciences , Alzahra University , Tehran , Iran
| | - Bita Ayati
- e Environmental Engineering Division, Civil and Environmental Engineering Faculty , Tarbiat Modares University , Tehran , Iran
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12
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Irankhah S, Abdi Ali A, Reza Soudi M, Gharavi S, Ayati B. Highly efficient phenol degradation in a batch moving bed biofilm reactor: benefiting from biofilm-enhancing bacteria. World J Microbiol Biotechnol 2018; 34:164. [PMID: 30368594 DOI: 10.1007/s11274-018-2543-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/20/2018] [Indexed: 11/26/2022]
Abstract
In this study, the efficiency improvement of three moving bed biofilm reactors (MBBRs) was investigated by inoculation of activated sludge cells (R1), mixed culture of eight strong phenol-degrading bacteria consisted of Pseudomonas spp. and Acinetobacter spp. (R2) and the combination of both (R3). Biofilm formation ability of eight bacteria was assessed initially using different methods and media. Maximum degradation of phenol, COD, biomass growth and also changes in organic loading shock were used as parameters to measure the performance of reactors. According to the results, all eight strains were determined as enhanced biofilm forming bacteria (EBFB). Under optimum operating conditions, more than 90% of initial COD load of 2795 mg L-1 was reduced at 24 HRT in R3 while this reduction efficiency was observed in concentrations of 1290 mg L-1 and 1935 mg L-1, in R1 and R2, respectively. When encountering phenol loading shock-twice greater than optimum amount-R1, R2 and R3 managed to return to the steady-state condition within 32, 24 and 18 days, respectively. SEM microscopy and biomass growth measurements confirmed the contribution of more cells to biofilm formation in R3 followed by R2. Additionally, established biofilm in R3 was more resistant to phenol loading shock which can be attributed to the enhancer role of EBFB strains in this reactor. It has been demonstrated that the bacteria with both biofilm-forming and contaminant-degrading abilities are not only able to promote the immobilization of other favorable activated sludge cells in biofilm structure, but also cooperate in contaminant degradation which all consequently lead to improvement of treatment efficiency.
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Affiliation(s)
- Sahar Irankhah
- Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, 1993891176, Iran
| | - Ahya Abdi Ali
- Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, 1993891176, Iran.
| | - Mohammad Reza Soudi
- Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, 1993891176, Iran
| | - Sara Gharavi
- Department of Biotechnology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran
| | - Bita Ayati
- Environmental Engineering Division, Civil and Environmental Engineering Faculty, Tarbiat Modares University, Tehran, Iran
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13
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Song Y, He JZ, Wang RK, Ma JZ, Zou L. Effect of SrtA on Interspecies Adherence of Oral Bacteria. Curr Med Sci 2018; 38:160-166. [PMID: 30074166 DOI: 10.1007/s11596-018-1860-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 12/05/2017] [Indexed: 02/05/2023]
Abstract
This study aimed to study whether the Sortase A (srtA) gene helps mediate coaggregation and co-adherence between Streptococcus mutans (S. mutans) and other salivary bacteria. S. mutans UA159 and srtA-deficient mutant served as "bait" in classical co-aggregation assays and membrane-based co-adherence assays were used to examine interactions of S. mutans with Fusobacterium nucleatum (F. nucleatum), Streptococcus mitis (S. mitis), Streptococcus gordonii (S. gordonii), Streptococcus sanguis (S. sanguis), Actinomyces naeslundii (A. naeslundii) and Lactobacillus. Co-adherence assays were also performed using unfractionated saliva from healthy individuals. Co-adhering partners of S. mutans were sensitively detected using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Both UA159 and its srtA-deficient mutant bound to F. nucleatum but not to any of the other five salivary bacteria. The srtA-deficient mutant showed lower co-adherence with F.nucleatum. The two S. mutans strains also showed similar co-adherence profiles against unfractionated salivary bacteria, except that UA159 S. mutans but not the srtA-deficient bound to a Neisseria sp. under the same conditions. Deleting srtA reduces the ability of S. mutans to bind to F.nucleatum, but it does not appear to significantly affect the binding profile of S. mutans to bulk salivary bacteria.
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Affiliation(s)
- Ying Song
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Conservation Dentistry and Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, 401147, China
| | - Jin-Zhi He
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Conservation Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Ren-Ke Wang
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, 610041, China.,Department of Conservation Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China
| | - Jing-Zhi Ma
- Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Ling Zou
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, 610041, China. .,Department of Conservation Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
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14
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Tsagkari E, Sloan WT. Turbulence accelerates the growth of drinking water biofilms. Bioprocess Biosyst Eng 2018; 41:757-770. [PMID: 29428998 PMCID: PMC5958169 DOI: 10.1007/s00449-018-1909-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 02/06/2018] [Indexed: 11/14/2022]
Abstract
Biofilms are found at the inner surfaces of drinking water pipes and, therefore, it is essential to understand biofilm processes to control their formation. Hydrodynamics play a crucial role in shaping biofilms. Thus, knowing how biofilms form, develop and disperse under different flow conditions is critical in the successful management of these systems. Here, the development of biofilms after 4 weeks, the initial formation of biofilms within 10 h and finally, the response of already established biofilms within 24-h intervals in which the flow regime was changed, were studied using a rotating annular reactor under three different flow regimes: turbulent, transition and laminar. Using fluorescence microscopy, information about the number of microcolonies on the reactor slides, the surface area of biofilms and of extracellular polymeric substances and the biofilm structures was acquired. Gravimetric measurements were conducted to characterise the thickness and density of biofilms, and spatial statistics were used to characterise the heterogeneity and spatial correlation of biofilm structures. Contrary to the prevailing view, it was shown that turbulent flow did not correlate with a reduction in biofilms; turbulence was found to enhance both the initial formation and the development of biofilms on the accessible surfaces. Additionally, after 24-h changes of the flow regime it was indicated that biofilms responded to the quick changes of the flow regime. Overall, this work suggests that different flow conditions can cause substantial changes in biofilm morphology and growth and specifically that turbulent flow can accelerate biofilm growth in drinking water.
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Affiliation(s)
- E Tsagkari
- College of Science and Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK.
| | - W T Sloan
- College of Science and Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK
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15
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Yoon HY, Lee SY. Establishing a laboratory model of dental unit waterlines bacterial biofilms using a CDC biofilm reactor. BIOFOULING 2017; 33:917-926. [PMID: 29160100 DOI: 10.1080/08927014.2017.1391950] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/06/2017] [Indexed: 06/07/2023]
Abstract
In this study, a laboratory model to reproduce dental unit waterline (DUWL) biofilms was developed using a CDC biofilm reactor (CBR). Bacteria obtained from DUWLs were filtered and cultured in Reasoner's 2A (R2A) for 10 days, and were subsequently stored at -70°C. This stock was cultivated on R2A in batch mode. After culturing for five days, the bacteria were inoculated into the CBR. Biofilms were grown on polyurethane tubing for four days. Biofilm accumulation and thickness was 1.3 × 105 CFU cm-2 and 10-14 μm respectively, after four days. Bacteria in the biofilms included cocci and rods of short and medium lengths. In addition, 38 bacterial genera were detected in biofilms. In this study, the suitability and reproducibility of the CBR model for DUWL biofilm formation were demonstrated. The model provides a foundation for the development of bacterial control methods for DUWLs.
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Affiliation(s)
- Hye Young Yoon
- a Department of Oral Microbiology, College of Dentistry, Research Institute of Oral Science , Gangneung-Wonju National University , Gangneung , Korea
| | - Si Young Lee
- a Department of Oral Microbiology, College of Dentistry, Research Institute of Oral Science , Gangneung-Wonju National University , Gangneung , Korea
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16
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A Keystone Methylobacterium Strain in Biofilm Formation in Drinking Water. WATER 2017. [DOI: 10.3390/w9100778] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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17
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The Behavior of Staphylococcus aureus Dual-Species Biofilms Treated with Bacteriophage phiIPLA-RODI Depends on the Accompanying Microorganism. Appl Environ Microbiol 2017; 83:AEM.02821-16. [PMID: 27836851 DOI: 10.1128/aem.02821-16] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/07/2016] [Indexed: 02/07/2023] Open
Abstract
The use of bacteriophages as antimicrobials against pathogenic bacteria offers a promising alternative to traditional antibiotics and disinfectants. Significantly, phages may help to remove biofilms, which are notoriously resistant to commonly used eradication methods. However, the successful development of novel antibiofilm strategies must take into account that real-life biofilms usually consist of mixed-species populations. Within this context, this study aimed to explore the effectiveness of bacteriophage-based sanitation procedures for removing polymicrobial biofilms from food industry surfaces. We treated dual-species biofilms formed by the food pathogenic bacterium Staphylococcus aureus in combination with Lactobacillus plantarum, Enterococcus faecium, or Lactobacillus pentosus with the staphylococcal phage phiIPLA-RODI. Our results suggest that the impact of bacteriophage treatment on S. aureus mixed-species biofilms varies depending on the accompanying species and the infection conditions. For instance, short treatments (4 h) with a phage suspension under nutrient-limiting conditions reduced the number of S. aureus cells in 5-h biofilms by ∼1 log unit without releasing the nonsusceptible species. In contrast, longer infection periods (18 h) with no nutrient limitation increased the killing of S. aureus cells by the phage (decrease of up to 2.9 log units). However, in some cases, these conditions promoted the growth of the accompanying species. For example, the L. plantarum cell count in the treated sample was up to 2.3 log units higher than that in the untreated control. Furthermore, phage propagation inside dual-species biofilms also depended greatly on the accompanying species, with the highest rate detected in biofilms formed by S. aureus-L. pentosus Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) also showed changes in the three-dimensional structures of the mixed-species biofilms after phage treatment. Altogether, the results presented here highlight the need to study the impact of phage therapy on microbial communities that reflect a more realistic setting. IMPORTANCE Biofilms represent a major source of contamination in industrial and hospital settings. Therefore, developing efficient strategies to combat bacterial biofilms is of the utmost importance from medical and economic perspectives. Bacteriophages have shown potential as novel antibiofilm agents, but further research is still required to fully understand the interactions between phages and biofilm-embedded bacteria. The results presented in this study contribute to achieving a better understanding of such interactions in a more realistic context, considering that most biofilms in the environment consist of mixed-species populations.
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18
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Naz I, Hodgson D, Smith A, Marchesi J, Ahmed S, Avignone-Rossa C, Saroj DP. Effect of the chemical composition of filter media on the microbial community in wastewater biofilms at different temperatures. RSC Adv 2016; 6:104345-104353. [PMID: 28018581 PMCID: PMC5154295 DOI: 10.1039/c6ra21040f] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 10/24/2016] [Indexed: 01/22/2023] Open
Abstract
This study investigates the microbial community composition in the biofilms grown on two different support media in fixed biofilm reactors for aerobic wastewater treatment, using next generation sequencing (NGS) technology. The chemical composition of the new type of support medium (TDR) was found to be quite different from the conventionally used support medium (stone). The analysis of 16S rRNA gene fragments recovered from the laboratory scale biofilm system show that biofilm support media and temperature conditions influence bacterial community structure and composition. Greater bacterial diversity was observed under each condition, primarily due to the large number of sequences available and sustenance of rare species. There were 6 phyla found, with the highest relative abundance shown by the phylum Proteobacteria (52.71%) followed by Bacteroidetes (33.33%), Actinobacteria (4.65%), Firmicutes, Verrucomicrobia (3.1%) and Chloroflex (>1%). The dataset showed 17 genera of bacterial populations to be commonly shared under all conditions, suggesting the presence of a core microbial community in the biofilms for wastewater treatment. However, some genera in the biofilms on TDR were observed in high proportions, which may be attributed to its chemical composition, explaining the improved level of wastewater treatment. The findings show that the structure of microbial communities in biofilm systems for wastewater treatment is affected by the properties of support matrix.
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Affiliation(s)
- Iffat Naz
- Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK. ; Department of Biology, Qassim University, Buraidah 51452, Kingdom of Saudi Arabia; Environmental Microbiology Laboratory, Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan; Department of Microbial Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Douglas Hodgson
- Department of Microbial Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Ann Smith
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3XQ, UK
| | - Julian Marchesi
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3XQ, UK; Centre for Digestive and Gut Health, Imperial College London, London W2 1NY, UK
| | - Safia Ahmed
- Environmental Microbiology Laboratory, Department of Microbiology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | | | - Devendra P Saroj
- Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK.
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19
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Rizzo G, Baroni L. Health and ecological implications of fish consumption: A deeper insight. MEDITERRANEAN JOURNAL OF NUTRITION AND METABOLISM 2016. [DOI: 10.3233/mnm-160054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Gianluca Rizzo
- Nutrition Ecology International Center (NEIC), Torino, Italy
| | - Luciana Baroni
- Primary Care Unit, Northern District, U.L.S.S. No. 9, Treviso, Italy
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20
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Jordaan K, Bezuidenhout CC. Bacterial community composition of an urban river in the North West Province, South Africa, in relation to physico-chemical water quality. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:5868-5880. [PMID: 26593724 DOI: 10.1007/s11356-015-5786-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/09/2015] [Indexed: 06/05/2023]
Abstract
The aim of this study was to determine the impacts of anthropogenic disturbances on bacterial community composition in an urban river (Mooi River). Physico-chemical analysis, bacterial enumeration and 454-pyrosequencing were conducted on the Mooi River system upstream and downstream of an urban settlement in the North West Province, South Africa. Pyrosequencing and multivariate analysis showed that nutrient inputs and faecal pollution strongly impacted the physico-chemical and microbiological quality at the downstream sites. Also, bacterial communities showed higher richness and evenness at the downstream sites. Multivariate analysis suggested that the abundances of Betaproteobacteria, Epsilonproteobacteria, Acidobacteria, Bacteroidetes and Verrucomicrobia are related to temperature, pH, dissolved oxygen (DO), sulphate and chlorophyll-a levels. These results suggest that urbanisation caused the overall water quality of this river to deteriorate, which in turn affected the bacterial community composition. In addition, our work identified potential indicator groups that may be used to track faecal and organic pollution in freshwater systems.
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Affiliation(s)
- K Jordaan
- Unit for Environmental Science and Management, North-West University, Potchefstroom Campus, Private Bag X6001, Potchefstroom, 2520, South Africa
| | - C C Bezuidenhout
- Unit for Environmental Science and Management, North-West University, Potchefstroom Campus, Private Bag X6001, Potchefstroom, 2520, South Africa.
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21
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Said Al-Adawi A, C. Gaylarde C, Sunner J, B. Beech I. Transfer of bacteria between stainless steel and chicken meat: A CLSM and DGGE study of biofilms. AIMS Microbiol 2016. [DOI: 10.3934/microbiol.2016.3.340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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22
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Stevens MRE, Luo TL, Vornhagen J, Jakubovics NS, Gilsdorf JR, Marrs CF, Møretrø T, Rickard AH. Coaggregation occurs between microorganisms isolated from different environments. FEMS Microbiol Ecol 2015; 91:fiv123. [DOI: 10.1093/femsec/fiv123] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2015] [Indexed: 11/12/2022] Open
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23
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Vinod Kumar K, Lall C, Raj RV, Vedhagiri K, Vijayachari P. Coexistence and survival of pathogenic leptospires by formation of biofilm withAzospirillum. FEMS Microbiol Ecol 2015; 91:fiv051. [DOI: 10.1093/femsec/fiv051] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2015] [Indexed: 11/13/2022] Open
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24
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Silver-zinc redox-coupled electroceutical wound dressing disrupts bacterial biofilm. PLoS One 2015; 10:e0119531. [PMID: 25803639 PMCID: PMC4372374 DOI: 10.1371/journal.pone.0119531] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 01/20/2015] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa biofilm is commonly associated with chronic wound infection. A FDA approved wireless electroceutical dressing (WED), which in the presence of conductive wound exudate gets activated to generate electric field (0.3–0.9V), was investigated for its anti-biofilm properties. Growth of pathogenic P. aeruginosa strain PAO1 in LB media was markedly arrested in the presence of the WED. Scanning electron microscopy demonstrated that WED markedly disrupted biofilm integrity in a setting where silver dressing was ineffective. Biofilm thickness and number of live bacterial cells were decreased in the presence of WED. Quorum sensing genes lasR and rhlR and activity of electric field sensitive enzyme, glycerol-3-phosphate dehydrogenase was also repressed by WED. This work provides first electron paramagnetic resonance spectroscopy evidence demonstrating that WED serves as a spontaneous source of reactive oxygen species. Redox-sensitive multidrug efflux systems mexAB and mexEF were repressed by WED. Taken together, these observations provide first evidence supporting the anti-biofilm properties of WED.
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25
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Godoy-Gallardo M, Wang Z, Shen Y, Manero JM, Gil FJ, Rodriguez D, Haapasalo M. Antibacterial coatings on titanium surfaces: a comparison study between in vitro single-species and multispecies biofilm. ACS APPLIED MATERIALS & INTERFACES 2015; 7:5992-6001. [PMID: 25734758 DOI: 10.1021/acsami.5b00402] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Dental plaque is a biofilm that causes dental caries, gingivitis, and periodontitis. Most of the studies in antibacterial coatings have been conducted by in vitro single-species biofilm formation, but oral biofilm involves more than 700 different bacterial species that are able to interact. Therefore, new studies are focused on in vitro multispecies biofilm models that mimic in vivo biofilms. The aim of the present work was to study different antibacterial coatings onto titanium surfaces and evaluate the in vitro antimicrobial properties of the surfaces on two different bacterial species and an oral biofilm. The lactate dehydrogenase assay determined that treated samples did not affect fibroblast viability. In addition, the viability of microorganisms on modified samples was evaluated by a LIVE/DEAD BacLight bacterial viability kit. Although a decrease in viable bacteria onto treated samples was obtained, the results showed differences in effectiveness when single-biofilm and oral plaque were tested. It confirms, as we expected, the distinct sensitivities that bacterial strains have. Thus, this multispecies biofilms model holds a great potential to assess antibacterial properties onto samples for dental purposes.
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Affiliation(s)
- Maria Godoy-Gallardo
- †Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028, Barcelona, Spain
- ‡Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain
- §Centre for Research in NanoEngineering (CRNE)-UPC, C/Pascual i Vila 15, 08028, Barcelona, Spain
| | - Zhejun Wang
- #Division of Endodontics, Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
- ∥The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, Hubei 430079, PR China
| | - Ya Shen
- #Division of Endodontics, Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - José M Manero
- †Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028, Barcelona, Spain
- ‡Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain
- §Centre for Research in NanoEngineering (CRNE)-UPC, C/Pascual i Vila 15, 08028, Barcelona, Spain
| | - Francisco J Gil
- †Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028, Barcelona, Spain
- ‡Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain
- §Centre for Research in NanoEngineering (CRNE)-UPC, C/Pascual i Vila 15, 08028, Barcelona, Spain
| | - Daniel Rodriguez
- †Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028, Barcelona, Spain
- ‡Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), C/Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain
- §Centre for Research in NanoEngineering (CRNE)-UPC, C/Pascual i Vila 15, 08028, Barcelona, Spain
| | - Markus Haapasalo
- #Division of Endodontics, Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Li X, Kong H, Mout R, Saha K, Moyano DF, Robinson SM, Rana S, Zhang X, Riley MA, Rotello VM. Rapid identification of bacterial biofilms and biofilm wound models using a multichannel nanosensor. ACS NANO 2014; 8:12014-9. [PMID: 25454256 PMCID: PMC4278688 DOI: 10.1021/nn505753s] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/02/2014] [Indexed: 05/21/2023]
Abstract
Identification of infectious bacteria responsible for biofilm-associated infections is challenging due to the complex and heterogeneous biofilm matrix. To address this issue and minimize the impact of heterogeneity on biofilm identification, we developed a gold nanoparticle (AuNP)-based multichannel sensor to detect and identify biofilms based on their physicochemical properties. Our results showed that the sensor can discriminate six bacterial biofilms including two composed of uropathogenic bacteria. The capability of the sensor was further demonstrated through discrimination of biofilms in a mixed bacteria/mammalian cell in vitro wound model.
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Affiliation(s)
- Xiaoning Li
- Department of Chemistry and Biology Department, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Hao Kong
- Beijing Key Laboratory of Analytical Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing, 100084, People’s Republic of China
| | - Rubul Mout
- Department of Chemistry and Biology Department, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Krishnendu Saha
- Department of Chemistry and Biology Department, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Daniel F. Moyano
- Department of Chemistry and Biology Department, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Sandra M. Robinson
- Department of Chemistry and Biology Department, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Subinoy Rana
- Department of Chemistry and Biology Department, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Xinrong Zhang
- Beijing Key Laboratory of Analytical Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing, 100084, People’s Republic of China
| | - Margaret A. Riley
- Department of Chemistry and Biology Department, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
| | - Vincent M. Rotello
- Department of Chemistry and Biology Department, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
- Address correspondence to
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27
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Covalent immobilization of hLf1-11 peptide on a titanium surface reduces bacterial adhesion and biofilm formation. Acta Biomater 2014; 10:3522-34. [PMID: 24704699 DOI: 10.1016/j.actbio.2014.03.026] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 03/19/2014] [Accepted: 03/24/2014] [Indexed: 01/18/2023]
Abstract
Bacterial infection represents a major cause of implant failure in dentistry. A common approach to overcoming this issue and treating peri-implant infection consists in the use of antibiotics. However, the rise of multidrug-resistant bacteria poses serious concerns to this strategy. A promising alternative is the use of antimicrobial peptides due to their broad-spectrum activity against bacteria and reduced bacterial resistance responses. The aim of the present study was to determine the in vitro antibacterial activity of the human lactoferrin-derived peptide hLf1-11 anchored to titanium surfaces. To this end, titanium samples were functionalized with the hLf1-11 peptide either by silanization methods or physical adsorption. X-ray photoelectron spectroscopy analyses confirmed the successful covalent attachment of the hLf1-11 peptide onto titanium surfaces. Lactate dehydrogenase assay determined that hLf1-11 peptide did not affect fibroblast viability. An outstanding reduction in the adhesion and early stages of biofilm formation of Streptococcus sanguinis and Lactobacillus salivarius was observed on the biofunctionalized surfaces compared to control non-treated samples. Furthermore, samples coated with the hLf1-11 peptide inhibited the early stages of bacterial growth. Thus, this strategy holds great potential to develop antimicrobial biomaterials for dental applications.
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Hoellein T, Rojas M, Pink A, Gasior J, Kelly J. Anthropogenic litter in urban freshwater ecosystems: distribution and microbial interactions. PLoS One 2014; 9:e98485. [PMID: 24955768 PMCID: PMC4067278 DOI: 10.1371/journal.pone.0098485] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 05/03/2014] [Indexed: 11/19/2022] Open
Abstract
Accumulation of anthropogenic litter (i.e. garbage; AL) and its ecosystem effects in marine environments are well documented. Rivers receive AL from terrestrial habitats and represent a major source of AL to marine environments, but AL is rarely studied within freshwater ecosystems. Our objectives were to 1) quantify AL density in urban freshwaters, 2) compare AL abundance among freshwater, terrestrial, and marine ecosystems, and 3) characterize the activity and composition of AL biofilms in freshwater habitats. We quantified AL from the Chicago River and Chicago's Lake Michigan shoreline, and found that AL abundance in Chicago freshwater ecosystems was comparable to previously reported data for marine and terrestrial ecosystems, although AL density and composition differed among habitats. To assess microbial interactions with AL, we incubated AL and natural substrates in 3 freshwater ecosystems, quantified biofilm metabolism as gross primary production (GPP) and community respiration (CR), and characterized biofilm bacterial community composition via high-throughput sequencing of 16S rRNA genes. The main driver of biofilm community composition was incubation location (e.g., river vs pond), but there were some significant differences in biofilm composition and metabolism among substrates. For example, biofilms on organic substrates (cardboard and leaves) had lower GPP than hard substrates (glass, plastic, aluminum and tiles). In addition, bacterial communities on organic substrates were distinct in composition from those on hard substrates, with higher relative abundances of bacteria associated with cellulose decomposition. Finally, we used our results to develop a conceptual diagram designed to unite the study of AL in terrestrial and freshwater environments with the well-established field of marine debris research. We suggest this broad perspective will be useful for future studies which synthesize AL sources, ecosystem effects, and fate across multiple ecosystem types, and will benefit management and reduction of global AL accumulations.
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Affiliation(s)
- Timothy Hoellein
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Miguel Rojas
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Adam Pink
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Joseph Gasior
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - John Kelly
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
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Cheng Z, Meng X, Wang H, Chen M, Li M. Isolation and characterization of broad spectrum coaggregating bacteria from different water systems for potential use in bioaugmentation. PLoS One 2014; 9:e94220. [PMID: 24736645 PMCID: PMC3988075 DOI: 10.1371/journal.pone.0094220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 03/13/2014] [Indexed: 01/30/2023] Open
Abstract
The bridging bacteria with broad-spectrum coaggregation ability play an important role during multispecies-biofilm development. In this study, through a visual and semi-quantitative assay, twenty-two bacterial strains with aggregation ability were obtained from 8 different water environments, and these strains were assigned to 7 genera according to their 16S rDNA and they were Aeromonas, Bacillus, Comamonas, Exiguobacterium, Pseudomonas, Shewanella and Comamonas. Furthermore, all possible 231 pairwise combinations among these 22 strains were explored for coaggregation ability by spectrophotometric assay. Among all these strains, it was found that Bacillus cereus G5 and Bacillus megaterium T1 coaggregated with themajority of assayed other strains, 90.5% (19 of 21 strains) and 76.2% respectively (17 of 21 strains) at a higher coaggregation rates (A.I. greater than 50%), indicating they have a broad-spectrum coaggregation property. The images of coaggregates also confirmed the coexistence of G5 and T1 with their partner strains. Biofilm biomass development of G5 cocultured with each of its partner strains were further evaluateded. The results showed that 15 of 21 strains, when paired with G5, developed greater biofilm biomass than the monocultures. Furthermore, the images from both fluorescence microscopy and scanning electron microscopy (SEM) demonstrated that G5 and A3-GFP (a 3,5-dinitrobenzoic acid-degrading strain, staining with gfp),could develop a typical spatial structure of dual-species biofilm when cocultured. These results suggested that bridging-bacteria with a broad spectrum coaggregating ability, such as G5,could mediate the integration of exogenous degrading bacteria into biofilms and contribute to the bioaugmentation treatment.
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Affiliation(s)
- Zhongqin Cheng
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, PR China
| | - Xiangxun Meng
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, PR China
| | - Haichao Wang
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, PR China
| | - Mei Chen
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, PR China
| | - Mengying Li
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, PR China
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Vornhagen J, Stevens M, McCormick D, Dowd SE, Eisenberg JN, Boles BR, Rickard AH. Coaggregation occurs amongst bacteria within and between biofilms in domestic showerheads. BIOFOULING 2013. [PMID: 23194413 PMCID: PMC4199578 DOI: 10.1080/08927014.2012.744395] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Showerheads support the development of multi-species biofilms that can be unsightly, produce malodor, and may harbor pathogens. The outer-surface spray-plates of many showerheads support visible biofilms that likely contain a mixture of bacteria from freshwater and potentially from human users. Coaggregation, a mechanism by which genetically distinct bacteria specifically recognize one another, may contribute to the retention and enrichment of different species within these biofilms. The aim of this work was to describe the bacterial composition of outer spray-plate biofilms of three domestic showerheads and to determine the intra- and inter-biofilm coaggregation ability of each culturable isolate. The bacterial composition of the three biofilms was determined by using bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) and by culturing on R2A medium. An average of 31 genera per biofilm were identified using bTEFAP and a total of 30 isolates were cultured. Even though the microbial diversity of each showerhead biofilm differed, every cultured isolate was able to coaggregate with at least one other isolate from the same or different showerhead biofilm. Promiscuous coaggregating isolates belonged to the genera Brevundimonas, Micrococcus, and Lysobacter. This work suggests that coaggregation may be a common feature of showerhead biofilms. Characterization of the mechanisms mediating coaggregation, and the inter-species interactions they facilitate, may allow for novel strategies to inhibit biofilm development.
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Affiliation(s)
- Jay Vornhagen
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Michael Stevens
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - David McCormick
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Scot E. Dowd
- Molecular Research LP (MR DNA), Shallowater, TX, 79363, USA
| | - Joseph N.S. Eisenberg
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Blaise R. Boles
- Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Alexander H. Rickard
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
- Corresponding author: Alexander H. Rickard, Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA, , Tel: (734)6158491
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Laanto E, Bamford JKH, Laakso J, Sundberg LR. Phage-driven loss of virulence in a fish pathogenic bacterium. PLoS One 2012; 7:e53157. [PMID: 23308090 PMCID: PMC3534065 DOI: 10.1371/journal.pone.0053157] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 11/26/2012] [Indexed: 01/17/2023] Open
Abstract
Parasites provide a selective pressure during the evolution of their hosts, and mediate a range of effects on ecological communities. Due to their short generation time, host-parasite interactions may also drive the virulence of opportunistic bacteria. This is especially relevant in systems where high densities of hosts and parasites on different trophic levels (e.g. vertebrate hosts, their bacterial pathogens, and virus parasitizing bacteria) co-exist. In farmed salmonid fingerlings, Flavobacterium columnare is an emerging pathogen, and phage that infect F. columnare have been isolated. However, the impact of these phage on their host bacterium is not well understood. To study this, four strains of F. columnare were exposed to three isolates of lytic phage and the development of phage resistance and changes in colony morphology were monitored. Using zebrafish (Danio rerio) as a model system, the ancestral rhizoid morphotypes were associated with a 25-100% mortality rate, whereas phage-resistant rough morphotypes that lost their virulence and gliding motility (which are key characteristics of the ancestral types), did not affect zebrafish survival. Both morphotypes maintained their colony morphologies over ten serial passages in liquid culture, except for the low-virulence strain, Os06, which changed morphology with each passage. To our knowledge, this is the first report of the effects of phage-host interactions in a commercially important fish pathogen where phage resistance directly correlates with a decline in bacterial virulence. These results suggest that phage can cause phenotypic changes in F. columnare outside the fish host, and antagonistic interactions between bacterial pathogens and their parasitic phage can favor low bacterial virulence under natural conditions. Furthermore, these results suggest that phage-based therapies can provide a disease management strategy for columnaris disease in aquaculture.
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Affiliation(s)
- Elina Laanto
- Centre of Excellence in Biological Interactions, Universities of Jyväskylä and Helsinki, Finland
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Jaana K. H. Bamford
- Centre of Excellence in Biological Interactions, Universities of Jyväskylä and Helsinki, Finland
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Jouni Laakso
- Centre of Excellence in Biological Interactions, Universities of Jyväskylä and Helsinki, Finland
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Lotta-Riina Sundberg
- Centre of Excellence in Biological Interactions, Universities of Jyväskylä and Helsinki, Finland
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- * E-mail:
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Kunttu HMT, Sundberg LR, Pulkkinen K, Valtonen ET. Environment may be the source of Flavobacterium columnare outbreaks at fish farms. ENVIRONMENTAL MICROBIOLOGY REPORTS 2012; 4:398-402. [PMID: 23760824 DOI: 10.1111/j.1758-2229.2012.00342.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Flavobacterium columnare, causing columnaris disease, was isolated for the first time from free water and biofilms in the environment outside fish farms. Fourteen isolates were found from Central Finland from a river by a water intake of a salmonid farm and 400 m upstream of the farm. One isolate was from a lake not under the influence of any fish farming. The bacterium could not be isolated from five other lakes in Central Finland or from three lakes in Eastern Finland, none of them in use for fish farming. Among the environmental isolates there was both genetic variability and difference in virulence, but the isolates were less virulent than the isolates originating from a disease outbreak at a fish farm. The isolates were able to survive for months outside the fish host and also to change their colony morphology, a phenomenon probably used as a survival strategy for F. columnare. This indicates that waters upstream of fish farms are a potential source of columnaris outbreaks at the farms during the summer. The results support the hypothesis that fish farms and farming practices may select for the virulent strains of F. columnare occurring in environmental waters to cause the infections at the farms.
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Affiliation(s)
- Heidi M T Kunttu
- Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland
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Catheter-associated bloodstream infection caused by Leifsonia aquatica in a haemodialysis patient: a case report. J Med Microbiol 2012; 61:868-873. [DOI: 10.1099/jmm.0.037457-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Phuong K, Hanazaki S, Kakii K, Nikata T. Involvement of Acinetobacter sp. in the floc-formation in activated sludge process. J Biotechnol 2012; 157:505-11. [DOI: 10.1016/j.jbiotec.2011.09.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 09/02/2011] [Accepted: 09/22/2011] [Indexed: 11/16/2022]
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Besemer K, Peter H, Logue JB, Langenheder S, Lindström ES, Tranvik LJ, Battin TJ. Unraveling assembly of stream biofilm communities. ISME JOURNAL 2012; 6:1459-68. [PMID: 22237539 PMCID: PMC3400417 DOI: 10.1038/ismej.2011.205] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Microbial biofilms assemble from cells that attach to a surface, where they develop into matrix-enclosed communities. Mechanistic insights into community assembly are crucial to better understand the functioning of natural biofilms, which drive key ecosystem processes in numerous aquatic habitats. We studied the role of the suspended microbial community as the source of the biofilm community in three streams using terminal-restriction fragment length polymorphism and 454 pyrosequencing of the 16S ribosomal RNA (rRNA) and the 16S rRNA gene (as a measure for the active and the bulk community, respectively). Diversity was consistently lower in the biofilm communities than in the suspended stream water communities. We propose that the higher diversity in the suspended communities is supported by continuous inflow from various sources within the catchment. Community composition clearly differed between biofilms and suspended communities, whereas biofilm communities were similar in all three streams. This suggests that biofilm assembly did not simply reflect differences in the source communities, but that certain microbial groups from the source community proliferate in the biofilm. We compared the biofilm communities with random samples of the respective community suspended in the stream water. This analysis confirmed that stochastic dispersal from the source community was unlikely to shape the observed community composition of the biofilms, in support of species sorting as a major biofilm assembly mechanism. Bulk and active populations generated comparable patterns of community composition in the biofilms and the suspended communities, which suggests similar assembly controls on these populations.
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An experimental model for the spatial structuring and selection of bacterial communities. J Microbiol Methods 2011; 87:165-8. [DOI: 10.1016/j.mimet.2011.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 08/17/2011] [Accepted: 08/17/2011] [Indexed: 11/27/2022]
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Kunttu HMT, Jokinen EI, Valtonen ET, Sundberg LR. Virulent and nonvirulent Flavobacterium columnare colony morphologies: characterization of chondroitin AC lyase activity and adhesion to polystyrene. J Appl Microbiol 2011; 111:1319-26. [PMID: 21914095 DOI: 10.1111/j.1365-2672.2011.05149.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Colony morphology variants of fish pathogenic Flavobacterium columnare were studied to clarify the role of colony morphology change in the virulence of the bacterium. Typical rhizoid colony (Rz) variants are virulent and moderately adherent, nonrhizoid rough (R) colony variants are nonvirulent and highly adherent, and soft colony (S) variants are nonvirulent and poorly adherent. METHODS AND RESULTS Chondroitin AC lyase activity, adhesion to polystyrene at different temperatures and after modification of bacterial surface, and lipopolysaccharide (LPS) profiles of the variants were studied. The chondroitinase activity was significantly higher in the virulent, rhizoid variants than in the rough variants of the same strain. Temperature significantly increased the adhesion of rhizoid variants up to 20°C. Modification of bacterial surface suggested that adhesion molecules contain both carbohydrates and proteins. LPS did not differ between the variants of the same strain. CONCLUSIONS The results suggest that in Fl. columnare both rhizoid colony morphology and high chondroitinase activity are needed for virulence and that temperature may promote the adhesion of the virulent variants to surfaces at fish farms. SIGNIFICANCE AND IMPACT OF THE STUDY New information is produced on the virulence mechanisms of Fl. columnare and the reasons behind the survival of the bacterium at fish farms.
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Affiliation(s)
- H M T Kunttu
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.
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Phage specificity of the freshwater fish pathogen Flavobacterium columnare. Appl Environ Microbiol 2011; 77:7868-72. [PMID: 21890667 DOI: 10.1128/aem.05574-11] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flavobacteria and their phages were isolated from Finnish freshwaters and fish farms. Emphasis was placed on finding phages infecting the fish pathogen Flavobacterium columnare for use as phage therapy agents. The host ranges of the flavobacterial phages varied, phages infecting F. columnare being more host specific than the other phages.
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Jacobs A, Chenia HY. Biofilm formation and adherence characteristics of an Elizabethkingia meningoseptica isolate from Oreochromis mossambicus. Ann Clin Microbiol Antimicrob 2011; 10:16. [PMID: 21545730 PMCID: PMC3112384 DOI: 10.1186/1476-0711-10-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 05/05/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Elizabethkingia spp. are opportunistic pathogens often found associated with intravascular device-related bacteraemias and ventilator-associated pneumonia. Their ability to exist as biofilm structures has been alluded to but not extensively investigated. METHODS The ability of Elizabethkingia meningoseptica isolate CH2B from freshwater tilapia (Oreochromis mossambicus) and E. meningoseptica strain NCTC 10016(T) to adhere to abiotic surfaces was investigated using microtiter plate adherence assays following exposure to varying physico-chemical challenges. The role of cell-surface properties was investigated using hydrophobicity (bacterial adherence to hydrocarbons), autoaggregation and coaggregation assays. The role of extracellular components in adherence was determined using reversal or inhibition of coaggregation assays in conjunction with Listeria spp. isolates, while the role of cell-free supernatants, from diverse bacteria, in inducing enhanced adherence was investigated using microtitre plate assays. Biofilm architecture of isolate CH2B alone as well as in co-culture with Listeria monocytogenes was investigated using flow cells and microscopy. RESULTS E. meningoseptica isolates CH2B and NCTC 10016(T) demonstrated stronger biofilm formation in nutrient-rich medium compared to nutrient-poor medium at both 21 and 37°C, respectively. Both isolates displayed a hydrophilic cell surface following the bacterial adherence to xylene assay. Varying autoaggregation and coaggregation indices were observed for the E. meningoseptica isolates. Coaggregation by isolate CH2B appeared to be strongest with foodborne pathogens like Enterococcus, Staphylococcus and Listeria spp. Partial inhibition of coaggregation was observed when isolate CH2B was treated with heat or protease exposure, suggesting the presence of heat-sensitive adhesins, although sugar treatment resulted in increased coaggregation and may be associated with a lactose-associated lectin or capsule-mediated attachment. CONCLUSIONS E. meningoseptica isolate CH2B and strain NCTC 10016(T) displayed a strong biofilm-forming phenotype which may play a role in its potential pathogenicity in both clinical and aquaculture environments. The ability of E. meningoseptica isolates to adhere to abiotic surfaces and form biofilm structures may result from the hydrophilic cell surface and multiple adhesins located around the cell.
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Affiliation(s)
- Anelet Jacobs
- Department of Microbiology, University of Stellenbosch, Private Bag X1, Matieland, 7602, South Africa
| | - Hafizah Y Chenia
- Discipline: Microbiology, University of KwaZulu-Natal, Private Bag X54001, Durban, 4001, South Africa
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Gião MS, Azevedo NF, Wilks SA, Vieira MJ, Keevil CW. Interaction of Legionella pneumophila and Helicobacter pylori with bacterial species isolated from drinking water biofilms. BMC Microbiol 2011; 11:57. [PMID: 21418578 PMCID: PMC3068934 DOI: 10.1186/1471-2180-11-57] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 03/18/2011] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND It is well established that Legionella pneumophila is a waterborne pathogen; by contrast, the mode of Helicobacter pylori transmission remains unknown but water seems to play an important role. This work aims to study the influence of five microorganisms isolated from drinking water biofilms on the survival and integration of both of these pathogens into biofilms. RESULTS Firstly, both pathogens were studied for auto- and co-aggregation with the species isolated from drinking water; subsequently the formation of mono and dual-species biofilms by L. pneumophila or H. pylori with the same microorganisms was investigated. Neither auto- nor co-aggregation was observed between the microorganisms tested. For biofilm studies, sessile cells were quantified in terms of total cells by SYTO 9 staining, viable L. pneumophila or H. pylori cells were quantified using 16 S rRNA-specific peptide nucleic acid (PNA) probes and cultivable cells by standard culture techniques. Acidovorax sp. and Sphingomonas sp. appeared to have an antagonistic effect on L. pneumophila cultivability but not on the viability (as assessed by rRNA content using the PNA probe), possibly leading to the formation of viable but noncultivable (VBNC) cells, whereas Mycobacterium chelonae increased the cultivability of this pathogen. The results obtained for H. pylori showed that M. chelonae and Sphingomonas sp. help this pathogen to maintain cultivability for at least 24 hours. CONCLUSIONS It appears that M. chelonae may have an important role in the survival of both pathogens in drinking water. This work also suggests that the presence of some microorganisms can decrease the cultivability of L. pneumophila but not the viability which indicates that the presence of autochthonous microorganisms can lead to misleading results when the safety of water is assessed by cultivable methods alone.
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Affiliation(s)
- Maria S Gião
- School of Biological Sciences, Life Sciences Building, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar 4710-057, Braga, Portugal
| | - Nuno F Azevedo
- School of Biological Sciences, Life Sciences Building, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar 4710-057, Braga, Portugal
- LEPAE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Sandra A Wilks
- School of Biological Sciences, Life Sciences Building, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
| | - Maria J Vieira
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar 4710-057, Braga, Portugal
| | - Charles W Keevil
- School of Biological Sciences, Life Sciences Building, Highfield Campus, University of Southampton, Southampton SO17 1BJ, UK
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Percival SL, Malic S, Cruz H, Williams DW. Introduction to Biofilms. SPRINGER SERIES ON BIOFILMS 2011. [DOI: 10.1007/978-3-642-21289-5_2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Role of planktonic and sessile extracellular metabolic byproducts on Pseudomonas aeruginosa and Escherichia coli intra and interspecies relationships. J Ind Microbiol Biotechnol 2010; 38:133-40. [PMID: 20811926 DOI: 10.1007/s10295-010-0838-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 07/26/2010] [Indexed: 02/07/2023]
Abstract
Bacterial species are found primarily as residents of complex surface-associated communities, known as biofilms. Although these structures prevail in nature, bacteria still exist in planktonic lifestyle and differ from those in morphology, physiology, and metabolism. This study aimed to investigate the influence of physiological states of Pseudomonas aeruginosa and Escherichia coli in cell-to-cell interactions. Filtered supernatants obtained under planktonic and biofilm cultures of each single species were supplemented with tryptic soy broth (TSB) and used as the growth media (conditioned media) to planktonic and sessile growth of both single- and two-species cultures. Planktonic bacterial growth was examined through OD(640) measurement. One-day-old biofilms were evaluated in terms of biofilm biomass (CV), respiratory activity (XTT), and CFU number. Conditioned media obtained either in biofilm or in planktonic mode of life triggered a synergistic effect on planktonic growth, mainly for E. coli single cultures growing in P. aeruginosa supernatants. Biofilms grown in the presence of P. aeruginosa biofilms-derived metabolites presented less mass and activity. These events highlight that, when developed in biofilm, P. aeruginosa release signals or metabolites able to prejudice single and binary biofilm growth of others species and of their own species. However, products released by their planktonic counterparts did not impair biofilm growth or activity. E. coli, living as planktonic or sessile cultures, released signals and metabolites or removed un-beneficial compounds which promoted the growth and activity of all the species. Our findings revealed that inter and intraspecies behaviors depend on the involved bacteria and their adopted mode of life.
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Upadya MH, Kishen A. Influence of bacterial growth modes on the susceptibility to light-activated disinfection. Int Endod J 2010; 43:978-87. [DOI: 10.1111/j.1365-2591.2010.01717.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Adhesion and biofilm formation on polystyrene by drinking water-isolated bacteria. Antonie van Leeuwenhoek 2010; 98:317-29. [PMID: 20405208 DOI: 10.1007/s10482-010-9444-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 04/06/2010] [Indexed: 01/15/2023]
Abstract
This study was performed in order to characterize the relationship between adhesion and biofilm formation abilities of drinking water-isolated bacteria (Acinetobacter calcoaceticus, Burkholderia cepacia, Methylobacterium sp., Mycobacterium mucogenicum, Sphingomonas capsulata and Staphylococcus sp.). Adhesion was assessed by two distinct methods: thermodynamic prediction of adhesion potential by quantifying hydrophobicity and the free energy of adhesion; and by microtiter plate assays. Biofilms were developed in microtiter plates for 24, 48 and 72 h. Polystyrene (PS) was used as adhesion substratum. The tested bacteria had negative surface charge and were hydrophilic. PS had negative surface charge and was hydrophobic. The free energy of adhesion between the bacteria and PS was > 0 mJ/m(2) (thermodynamic unfavorable adhesion). The thermodynamic approach was inappropriate for modelling adhesion of the tested drinking water bacteria, underestimating adhesion to PS. Only three (B. cepacia, Sph. capsulata and Staphylococcus sp.) of the six bacteria were non-adherent to PS. A. calcoaceticus, Methylobacterium sp. and M. mucogenicum were weakly adherent. This adhesion ability was correlated with the biofilm formation ability when comparing with the results of 24 h aged biofilms. Methylobacterium sp. and M. mucogenicum formed large biofilm amounts, regardless the biofilm age. Given time, all the bacteria formed biofilms; even those non-adherents produced large amounts of matured (72 h aged) biofilms. The overall results indicate that initial adhesion did not predict the ability of the tested drinking water-isolated bacteria to form a mature biofilm, suggesting that other events such as phenotypic and genetic switching during biofilm development and the production of extracellular polymeric substances (EPS), may play a significant role on biofilm formation and differentiation. This understanding of the relationship between adhesion and biofilm formation is important for the development of control strategies efficient in the early stages of biofilm development.
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Hill KE, Malic S, McKee R, Rennison T, Harding KG, Williams DW, Thomas DW. An in vitro model of chronic wound biofilms to test wound dressings and assess antimicrobial susceptibilities. J Antimicrob Chemother 2010; 65:1195-206. [DOI: 10.1093/jac/dkq105] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Abstract
Oral biofilms develop under a range of different conditions and different environments. This review will discuss emerging concepts in microbial ecology and how they relate to oral biofilm development and the treatment of oral diseases. Clues to how oral biofilms develop may lie in other complex systems, such as interactions between host and gut microbiota, and even in factors that affect biofilm development on leaf surfaces. Most of the conditions under which oral biofilms develop are tightly linked to the overall health and biology of the host. Advances in molecular techniques have led to a greater appreciation of the diversity of human microbiota, the extent of interactions with the human host, and how that relates to inter-individual variation. As a consequence, plaque development may no longer be thought of as a generic process, but rather as a highly individualized process, which has ramifications for the treatment of the diseases it causes.
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Affiliation(s)
- S Filoche
- Dental Research Group, Department of Pathology and Molecular Medicine, University of Otago-Wellington, Wellington School of Medicine and Health Sciences, PO Box 7343, Mein Street, Wellington 6242, New Zealand.
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Abstract
Microorganisms can form tightly knit communities such as biofilms. Many others include marine snow, anaerobic digester granules, the ginger beer plant and bacterial colonies. This chapter is devoted to a survey of the main properties of these communities, with an emphasis on biofilms. We start with attachment to surfaces and the nature of adhesion. The growing community then forms within a matrix, generally of organic macromolecules. Inevitably the environment within such a matrix is different from that outside. Organisms respond by forming crowd-detection and response units; these quorum sensing systems act as switches between planktonic life and the dramatically altered conditions found inside microbial aggregates. The community then matures and changes and may even fail and disappear. Antimicrobial resistance is discussed as an example of multicellular behavior. The multicellular lifestyle has been modeled mathematically and responded to powerful molecular biological techniques. Latterly, microbial systems have been used as models for fundamental evolutionary processes, mostly because of their high rates of reproduction and the ease of genetic manipulation. The life of most microbes is a duality between the yin of the community and the yang of planktonic existence. Sadly far less research has been devoted to adaptation to free-living forms than in the opposite direction.
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Affiliation(s)
- Julian Wimpenny
- Cardiff School of Biosciences, Cardiff University, Cathays Park, Cardiff, Wales
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Pulkkinen K, Suomalainen LR, Read AF, Ebert D, Rintamäki P, Valtonen ET. Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland. Proc Biol Sci 2009; 277:593-600. [PMID: 19864284 DOI: 10.1098/rspb.2009.1659] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Ecological changes affect pathogen epidemiology and evolution and may trigger the emergence of novel diseases. Aquaculture radically alters the ecology of fish and their pathogens. Here we show an increase in the occurrence of the bacterial fish disease Flavobacterium columnare in salmon fingerlings at a fish farm in northern Finland over 23 years. We hypothesize that this emergence was owing to evolutionary changes in bacterial virulence. We base this argument on several observations. First, the emergence was associated with increased severity of symptoms. Second, F. columnare strains vary in virulence, with more lethal strains inducing more severe symptoms prior to death. Third, more virulent strains have greater infectivity, higher tissue-degrading capacity and higher growth rates. Fourth, pathogen strains co-occur, so that strains compete. Fifth, F. columnare can transmit efficiently from dead fish, and maintain infectivity in sterilized water for months, strongly reducing the fitness cost of host death likely experienced by the pathogen in nature. Moreover, this saprophytic infectiousness means that chemotherapy strongly select for strains that rapidly kill their hosts: dead fish remain infectious; treated fish do not. Finally, high stocking densities of homogeneous subsets of fish greatly enhance transmission opportunities. We suggest that fish farms provide an environment that promotes the circulation of more virulent strains of F. columnare. This effect is intensified by the recent increases in summer water temperature. More generally, we predict that intensive fish farming will lead to the evolution of more virulent pathogens.
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Affiliation(s)
- K Pulkkinen
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, FI-40014 Jyväskylä, Finland.
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Bacterial community composition of stream biofilms in spatially variable-flow environments. Appl Environ Microbiol 2009; 75:7189-95. [PMID: 19767473 DOI: 10.1128/aem.01284-09] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streams are highly heterogeneous ecosystems, in terms of both geomorphology and hydrodynamics. While flow is recognized to shape the physical architecture of benthic biofilms, we do not yet understand what drives community assembly and biodiversity of benthic biofilms in the heterogeneous flow landscapes of streams. Within a metacommunity ecology framework, we experimented with streambed landscapes constructed from bedforms in large-scale flumes to illuminate the role of spatial flow heterogeneity in biofilm community composition and biodiversity in streams. Our results show that the spatial variation of hydrodynamics explained a remarkable percentage (up to 47%) of the variation in community composition along bedforms. This suggests species sorting as a model of metacommunity dynamics in stream biofilms, though natural biofilm communities will clearly not conform to a single model offered by metacommunity ecology. The spatial variation induced by the hydrodynamics along the bedforms resulted in a gradient of bacterial beta diversity, measured by a range of diversity and similarity indices, that increased with bedform height and hence with spatial flow heterogeneity at the flume level. Our results underscore the necessity to maintain small-scale physical heterogeneity for community composition and biodiversity of biofilms in stream ecosystems.
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50
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Saprophytism of a fish pathogen as a transmission strategy. Epidemics 2009; 1:96-100. [DOI: 10.1016/j.epidem.2009.04.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 04/22/2009] [Accepted: 04/29/2009] [Indexed: 11/23/2022] Open
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