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Selci M, Correggia M, Cordone A, Guida M, Quero GM, Piredda R, Vetriani C, Ramirez C, Lloyd KG, de Moor JM, Barry PH, Schrenk MO, Giovannelli D. Recreational hot springs as environmental reservoir of potential multidrug-resistant pathogens. ENVIRONMENTAL RESEARCH 2024:119841. [PMID: 39182755 DOI: 10.1016/j.envres.2024.119841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 08/21/2024] [Accepted: 08/22/2024] [Indexed: 08/27/2024]
Affiliation(s)
- Matteo Selci
- Department of Biology, University of Naples Federico II, Naples, Italy; Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, USA
| | - Monica Correggia
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Angelina Cordone
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Marco Guida
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Grazia Marina Quero
- Institute for Marine Biological and Biotechnological Resources, National Research Council of Italy (CNR-IRBIM), Ancona, Italy
| | - Roberta Piredda
- Department of Veterinary Medicine - University of Bari Aldo Moro, Bari, Italy
| | - Costantino Vetriani
- Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, USA; Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, USA
| | | | - Karen G Lloyd
- Microbiology Department, University of Tennessee, Knoxville, TN, USA
| | - J Maarten de Moor
- Observatorio Volcanológico y Sismológico de Costa Rica (OVSICORI), Universidad Nacional, Heredia, Costa Rica
| | - Peter H Barry
- Marine Chemistry & Geochemistry Department - Woods Hole Oceanographic Institution, MA, USA
| | - Matthew O Schrenk
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, USA
| | - Donato Giovannelli
- Department of Biology, University of Naples Federico II, Naples, Italy; Institute for Marine Biological and Biotechnological Resources, National Research Council of Italy (CNR-IRBIM), Ancona, Italy; Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, USA; Marine Chemistry & Geochemistry Department - Woods Hole Oceanographic Institution, MA, USA; Earth-Life Science Institute, Tokyo Institute for Technology, Tokyo, Japan.
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Polymenakou PN, Nomikou P, Hannington M, Petersen S, Kilias SP, Anastasiou TI, Papadimitriou V, Zaka E, Kristoffersen JB, Lampridou D, Wind S, Heinath V, Lange S, Magoulas A. Taxonomic diversity of microbial communities in sub-seafloor hydrothermal sediments of the active Santorini-Kolumbo volcanic field. Front Microbiol 2023; 14:1188544. [PMID: 37455712 PMCID: PMC10345502 DOI: 10.3389/fmicb.2023.1188544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023] Open
Abstract
Introduction Active hydrothermal vents of volcanic origin provide a remarkable manifestation of life on Earth under extreme conditions, which may have consequences for our understanding of habitability on other terrestrial bodies as well. Methods Here, we performed for the first time Illumina sequencing of bacterial and archaeal communities on sub-seafloor samples collected from the Santorini-Kolumbo volcanic field. A total of 19 (3-m long) gravity corers were collected and processed for microbial community analysis. Results From a total of 6,46,671 produced V4 sequences for all samples, a total of 10,496 different Operational Taxonomic Units (OTUs) were identified that were assigned to 40 bacterial and 9 archaeal phyla and 14 candidate divisions. On average, the most abundant phyla in all samples were Chloroflexi (Chloroflexota) (24.62%), followed by Proteobacteria (Pseudomonadota) (11.29%), Firmicutes (Bacillota) (10.73%), Crenarchaeota (Thermoproteota) (8.55%), and Acidobacteria (Acidobacteriota) (8.07%). At the genus level, a total of 286 known genera and candidate genera were mostly dominated by members of Bacillus, Thermoflexus, Desulfatiglans, Pseudoalteromonas, and Pseudomonas. Discussion In most of the stations, the Chao1 values at the deeper layers were comparable to the surface sediment samples denoting the high diversity in the subsurface of these ecosystems. Heatmap analysis based on the 100 most abundant OTUs, grouped the sampling stations according to their geographical location, placing together the two hottest stations (up to 99°C). This result indicates that this specific area within the active Kolumbo crater create a distinct niche, where microorganisms with adaptation strategies to withstand heat stresses can thrive, such as the endospore-forming Firmicutes.
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Affiliation(s)
- Paraskevi N. Polymenakou
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology, and Aquaculture, Heraklion, Greece
| | - Paraskevi Nomikou
- Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, Greece
| | - Mark Hannington
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Sven Petersen
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Stephanos P. Kilias
- Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, Greece
| | - Thekla I. Anastasiou
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology, and Aquaculture, Heraklion, Greece
| | - Vasiliki Papadimitriou
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology, and Aquaculture, Heraklion, Greece
| | - Eleutheria Zaka
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology, and Aquaculture, Heraklion, Greece
- Department of Biology, University of Crete, Heraklion, Greece
| | - Jon Bent Kristoffersen
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology, and Aquaculture, Heraklion, Greece
| | - Danai Lampridou
- Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, Greece
| | - Sandra Wind
- Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Verena Heinath
- Institute of Geosciences, University of Kiel (CAU), Kiel, Germany
| | - Sabine Lange
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Antonios Magoulas
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology, and Aquaculture, Heraklion, Greece
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Salvà-Serra F, Pérez-Pantoja D, Donoso RA, Jaén-Luchoro D, Fernández-Juárez V, Engström-Jakobsson H, Moore ERB, Lalucat J, Bennasar-Figueras A. Comparative genomics of Stutzerimonas balearica ( Pseudomonas balearica): diversity, habitats, and biodegradation of aromatic compounds. Front Microbiol 2023; 14:1159176. [PMID: 37275147 PMCID: PMC10234333 DOI: 10.3389/fmicb.2023.1159176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 04/13/2023] [Indexed: 06/07/2023] Open
Abstract
Stutzerimonas balearica (Pseudomonas balearica) has been found principally in oil-polluted environments. The capability of S. balearica to thrive from the degradation of pollutant compounds makes it a species of interest for potential bioremediation applications. However, little has been reported about the diversity of S. balearica. In this study, genome sequences of S. balearica strains from different origins were analyzed, revealing that it is a diverse species with an open pan-genome that will continue revealing new genes and functionalities as the genomes of more strains are sequenced. The nucleotide signatures and intra- and inter-species variation of the 16S rRNA genes of S. balearica were reevaluated. A strategy of screening 16S rRNA gene sequences in public databases enabled the detection of 158 additional strains, of which only 23% were described as S. balearica. The species was detected from a wide range of environments, although mostly from aquatic and polluted environments, predominantly related to petroleum oil. Genomic and phenotypic analyses confirmed that S. balearica possesses varied inherent capabilities for aromatic compounds degradation. This study increases the knowledge of the biology and diversity of S. balearica and will serve as a basis for future work with the species.
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Affiliation(s)
- Francisco Salvà-Serra
- Microbiology, Department of Biology, University of the Balearic Islands, Palma de Mallorca, Spain
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Culture Collection University of Gothenburg (CCUG), Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Danilo Pérez-Pantoja
- Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Santiago, Chile
| | - Raúl A. Donoso
- Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Santiago, Chile
- Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
| | - Daniel Jaén-Luchoro
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Culture Collection University of Gothenburg (CCUG), Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Víctor Fernández-Juárez
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Hedvig Engström-Jakobsson
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Edward R. B. Moore
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Culture Collection University of Gothenburg (CCUG), Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jorge Lalucat
- Microbiology, Department of Biology, University of the Balearic Islands, Palma de Mallorca, Spain
| | - Antoni Bennasar-Figueras
- Microbiology, Department of Biology, University of the Balearic Islands, Palma de Mallorca, Spain
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Huang Q, Huang Y, Li B, Li X, Guo Y, Jiang Z, Liu X, Yang Z, Ning Z, Xiao T, Jiang C, Hao L. Metagenomic analysis characterizes resistomes of an acidic, multimetal(loid)-enriched coal source mine drainage treatment system. JOURNAL OF HAZARDOUS MATERIALS 2023; 448:130898. [PMID: 36731323 DOI: 10.1016/j.jhazmat.2023.130898] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/07/2023] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
Heavy metal(loid) contaminations caused by mine activities are potential hot spots of antibiotic resistance genes (ARGs) because of heavy metal(loid)-induced co-selection of ARGs and heavy metal(loid) resistance genes (MRGs). This study used high-throughput metagenomic sequencing to analyze the resistome characteristics of a coal source acid mine drainage passive treatment system. The multidrug efflux mechanism dominated the antibiotic resistome, and a highly diverse heavy metal(loid) resistome was dominated by mercury-, iron-, and arsenic--associated resistance. Correlation analysis indicated that mobile gene elements had a greater influence on the dynamic of MRGs than ARGs. Among the metagenome-assembled genomes, six potential pathogens carrying multiple resistance genes resistant to several antibiotics and heavy metal(loid)s were recovered. Pseudomonas spp. contained the highest numbers of resistance genes, with resistance to two types of antibiotics and 12 types of heavy metal(loid)s. Thus, high contents of heavy metal(loid)s drove the co-selection of ARGs and MRGs. The occurrence of potential pathogens containing multiple resistance genes might increase the risk of ARG dissemination in the environment.
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Affiliation(s)
- Qiang Huang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Ye Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Bao Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xiutong Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Yuan Guo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Zhen Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xiaoling Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Zhenni Yang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Zengping Ning
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Tangfu Xiao
- Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, PR China
| | - Chengying Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
| | - Likai Hao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, PR China.
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Robas Mora M, Fernández Pastrana VM, González Reguero D, Gutiérrez Oliva LL, Probanza Lobo A, Jiménez Gómez PA. Oxidative stress protection and growth promotion activity of Pseudomonas mercuritolerans sp. nov., in forage plants under mercury abiotic stress conditions. Front Microbiol 2022; 13:1032901. [PMID: 36560952 PMCID: PMC9763275 DOI: 10.3389/fmicb.2022.1032901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022] Open
Abstract
SAICEUPSMT strain was isolated from soils in the mining district of Almadén (Ciudad Real, Spain), subjected to a high concentration of mercury. Using the plant model of lupinus, the strain was inoculated into the rhizosphere of the plant in a soil characterized by a high concentration of mercury (1,710 ppm) from an abandoned dump in the mining district of Almadén (Ciudad Real, Spain). As a control, a soil with a minimum natural concentration of mercury, from a surrounding area, was used. Under greenhouse conditions, the effect that the inoculum of the SAICEUPSMT strain had on the antioxidant capacity of the plant was studied, through the quantification of the enzymatic activity catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD), and glutathione reductase (GR). Likewise, the capacity of the plant to bioaccumulate mercury in the presence of the inoculum was studied, as well as the effect on the biometric parameters total weight (g), shoot weight (g), root weight (g), shoot length (cm), root length (cm), total number of leaves (N), and total number of secondary roots (No). Finally, in view of the results, the SAICEUPSMT strain was identified from the phenotypic and genotypic point of view (housekeeping genes and complete genome sequencing). The inoculum with the SAICEUPSMT strain in the presence of mercury produced a significant reduction in the enzymatic response to oxidative stress (CAT, APX, and SOD). It can be considered that the strain exerts a phytoprotective effect on the plant. This led to a significant increase in the biometric parameters total plant weight, root weight and the number of leaves under mercury stress, compared to the control without abiotic stress. When analyzing the mercury content of the plant with and without bacterial inoculum, it was found that the incorporation of the SAICEUPSMT strain significantly reduced the uptake of mercury by the plant, while favoring its development in terms of biomass. Given the positive impact of the SAICEUPSMT strain on the integral development of the plant, it was identified, proving to be a Gram negative bacillus, in vitro producer of siderophores, auxins and molecules that inhibit stress precursors. The most represented fatty acids were C16:0 (33.29%), characteristic aggregate 3 (22.80%) comprising C16:1 ω7c and C16: 1ω6c, characteristic aggregate 8 (13.66%) comprising C18:1 ω7c, and C18: 1 cycle ω6c and C 17:0 (11.42%). From the genotypic point of view, the initial identification of the strain based on the 16S rRNA gene sequence classified it as Pseudomonas iranensis. However, genome-wide analysis showed that average nucleotide identity (ANI, 95.47%), DNA-DNA in silico hybridization (dDDH, 61.9%), average amino acid identity (AAI, 97.13%), TETRA (0.99%) and intergenic distance (0.04) values were below the established thresholds for differentiation. The results of the genomic analysis together with the differences in the phenotypic characteristics and the phylogenetic and chemotaxonomic analysis support the proposal of the SAICEUPSMT strain as the type strain of a new species for which the name Pseudomonas mercuritolerans sp. is proposed. No virulence genes or transmissible resistance mechanisms have been identified, which reveals its safety for agronomic uses, under mercury stress conditions.
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Affiliation(s)
- Marina Robas Mora
- Department of Health and Pharmaceutical Sciences, School of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | | | | | | | | | - Pedro A. Jiménez Gómez
- Department of Health and Pharmaceutical Sciences, School of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
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Wei M, Zeng X, Han X, Shao Z, Xie Q, Dong C, Wang Y, Qiu Z. Potential autotrophic carbon-fixer and Fe(II)-oxidizer Alcanivorax sp. MM125-6 isolated from Wocan hydrothermal field. Front Microbiol 2022; 13:930601. [PMID: 36316996 PMCID: PMC9616709 DOI: 10.3389/fmicb.2022.930601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 09/09/2022] [Indexed: 12/02/2022] Open
Abstract
The genus Alcanivorax is common in various marine environments, including in hydrothermal fields. They were previously recognized as obligate hydrocarbonoclastic bacteria, but their potential for autotrophic carbon fixation and Fe(II)-oxidation remains largely elusive. In this study, an in situ enrichment experiment was performed using a hydrothermal massive sulfide slab deployed 300 m away from the Wocan hydrothermal vent. Furthermore, the biofilms on the surface of the slab were used as an inoculum, with hydrothermal massive sulfide powder from the same vent as an energy source, to enrich the potential iron oxidizer in the laboratory. Three dominant bacterial families, Alcanivoraceae, Pseudomonadaceae, and Rhizobiaceae, were enriched in the medium with hydrothermal massive sulfides. Subsequently, strain Alcanivorax sp. MM125-6 was isolated from the enrichment culture. It belongs to the genus Alcanivorax and is closely related to Alcanivorax profundimaris ST75FaO-1T (98.9% sequence similarity) indicated by a phylogenetic analysis based on 16S rRNA gene sequences. Autotrophic growth experiments on strain MM125-6 revealed that the cell concentrations were increased from an initial 7.5 × 105 cells/ml to 3.13 × 108 cells/ml after 10 days, and that the δ13CVPDB in the cell biomass was also increased from 234.25‰ on day 2 to gradually 345.66 ‰ on day 10. The gradient tube incubation showed that bands of iron oxides and cells formed approximately 1 and 1.5 cm, respectively, below the air-agarose medium interface. In addition, the SEM-EDS data demonstrated that it can also secrete acidic exopolysaccharides and adhere to the surface of sulfide minerals to oxidize Fe(II) with NaHCO3 as the sole carbon source, which accelerates hydrothermal massive sulfide dissolution. These results support the conclusion that strain MM125-6 is capable of autotrophic carbon fixation and Fe(II) oxidization chemoautotrophically. This study expands our understanding of the metabolic versatility of the Alcanivorax genus as well as their important role(s) in coupling hydrothermal massive sulfide weathering and iron and carbon cycles in hydrothermal fields.
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Affiliation(s)
- Mingcong Wei
- Ocean College, Zhejiang University, Zhoushan, China
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Xiang Zeng
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Xiqiu Han
- Ocean College, Zhejiang University, Zhoushan, China
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
- *Correspondence: Xiqiu Han,
| | - Zongze Shao
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Qian Xie
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, China
| | - Chuanqi Dong
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
- College of Marine Geosciences, Ocean University of China, Qingdao, China
| | - Yejian Wang
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Zhongyan Qiu
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
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A Comprehensive Profile of Antibiotic Resistance Genes in the Water Column of a Shallow-Sea Hydrothermal Vent Ecosystem. SUSTAINABILITY 2022. [DOI: 10.3390/su14031776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Antibiotic resistance genes (ARGs) became an emerging contaminant, and were found to accumulate in natural and man-made environments. A comprehensive understanding of the diversity and abundance of ARGs in pristine environments is critical for defining the baseline levels of environmental ARGs. However, there is limited information available on the ARG profiles of pristine environments, especially for shallow-sea hydrothermal vents ecosystems. Here, we combined 16S rRNA gene full-length amplicon sequencing and high-throughput quantitative PCR (HT-qPCR) to study the bacterial communities, and ARG abundance and diversity in the shallow-sea hydrothermal vent ecosystem of the Kueishantao Islet. The results of the 16S rRNA gene amplicon sequencing showed that several sulfur-cycling related bacterial genera, including Thiomicrorhabdus, Thioreductor, Sulfurovum, Sulfurimonas and Lebetimonas, dominated in the water column of the shallow-sea system. Temperature was the significant factor shaping the bacterial communities. The results of HT-qPCR analysis showed that the Kueishantao shallow-sea system harbored the lowest diversity (average 10 ARG subtypes) and abundance (average 1.0 × 10−3 copy per bacterial cell) of ARGs compared with other pristine (i.e., Tibet lake sediments, marine water and sediments) and anthropogenic-disturbed (i.e., drinking water reservoirs, urban ponds and wastewater treatment plants) environments. Procrustes analysis demonstrated a concordant pattern between the compositions of bacterial communities and ARGs in the shallow-sea system, while variation partition analysis revealed that the shared effects of physicochemical and bacterial communities explained >80% of the variation in the composition of ARGs. These results suggest that the vent bacterial communities and local environmental factors played an important role in shaping the distribution of the ARG profiles. Our study provides the first comprehensive overview of the background level of ARGs in a shallow-sea hydrothermal vent ecosystem.
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