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Blanco P, Hipólito A, García-Pastor L, Trigo da Roza F, Toribio-Celestino L, Ortega A, Vergara E, San Millán Á, Escudero J. Identification of promoter activity in gene-less cassettes from Vibrionaceae superintegrons. Nucleic Acids Res 2024; 52:2961-2976. [PMID: 38214222 PMCID: PMC11014356 DOI: 10.1093/nar/gkad1252] [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: 04/18/2023] [Revised: 12/18/2023] [Accepted: 12/26/2023] [Indexed: 01/13/2024] Open
Abstract
Integrons are genetic platforms that acquire new genes encoded in integron cassettes (ICs), building arrays of adaptive functions. ICs generally encode promoterless genes, whose expression relies on the platform-associated Pc promoter, with the cassette array functioning as an operon-like structure regulated by the distance to the Pc. This is relevant in large sedentary chromosomal integrons (SCIs) carrying hundreds of ICs, like those in Vibrio species. We selected 29 gene-less cassettes in four Vibrio SCIs, and explored whether their function could be related to the transcription regulation of adjacent ICs. We show that most gene-less cassettes have promoter activity on the sense strand, enhancing the expression of downstream cassettes. Additionally, we identified the transcription start sites of gene-less ICs through 5'-RACE. Accordingly, we found that most of the superintegron in Vibrio cholerae is not silent. These promoter cassettes can trigger the expression of a silent dfrB9 cassette downstream, increasing trimethoprim resistance >512-fold in V. cholerae and Escherichia coli. Furthermore, one cassette with an antisense promoter can reduce trimethoprim resistance when cloned downstream. Our findings highlight the regulatory role of gene-less cassettes in the expression of adjacent cassettes, emphasizing their significance in SCIs and their clinical importance if captured by mobile integrons.
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Affiliation(s)
- Paula Blanco
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Alberto Hipólito
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Lucía García-Pastor
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Filipa Trigo da Roza
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Laura Toribio-Celestino
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Alba Cristina Ortega
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Ester Vergara
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Álvaro San Millán
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
- Centro de Investigación Biológica en Red de Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Madrid 28222, Spain
| | - José Antonio Escudero
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
- VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid 28040, Spain
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2
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Freddi S, Rajabal V, Tetu SG, Gillings MR, Penesyan A. Microbial biofilms on macroalgae harbour diverse integron gene cassettes. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001446. [PMID: 38488860 PMCID: PMC10963911 DOI: 10.1099/mic.0.001446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 02/27/2024] [Indexed: 03/19/2024]
Abstract
Integrons are genetic platforms that capture, rearrange and express mobile modules called gene cassettes. The best characterized gene cassettes encode antibiotic resistance, but the function of most integron gene cassettes remains unknown. Functional predictions suggest that many gene cassettes could encode proteins that facilitate interactions with other cells and with the extracellular environment. Because cell interactions are essential for biofilm stability, we sequenced gene cassettes from biofilms growing on the surface of the marine macroalgae Ulva australis and Sargassum linearifolium. Algal samples were obtained from coastal rock platforms around Sydney, Australia, using seawater as a control. We demonstrated that integrons in microbial biofilms did not sample genes randomly from the surrounding seawater, but harboured specific functions that potentially provided an adaptive advantage to both the bacterial cells in biofilm communities and their macroalgal host. Further, integron gene cassettes had a well-defined spatial distribution, suggesting that each bacterial biofilm acquired these genetic elements via sampling from a large but localized pool of gene cassettes. These findings suggest two forms of filtering: a selective acquisition of different integron-containing bacterial species into the distinct biofilms on Ulva and Sargassum surfaces, and a selective retention of unique populations of gene cassettes at each sampling location.
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Affiliation(s)
- Stefano Freddi
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, NSW 2109, Australia
| | - Vaheesan Rajabal
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, NSW 2109, Australia
- Australian Research Council Centre of Excellence in Synthetic Biology, Macquarie University, NSW 2109, Australia
| | - Sasha G. Tetu
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, NSW 2109, Australia
- Australian Research Council Centre of Excellence in Synthetic Biology, Macquarie University, NSW 2109, Australia
| | - Michael R. Gillings
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, NSW 2109, Australia
- Australian Research Council Centre of Excellence in Synthetic Biology, Macquarie University, NSW 2109, Australia
| | - Anahit Penesyan
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, NSW 2109, Australia
- Australian Research Council Centre of Excellence in Synthetic Biology, Macquarie University, NSW 2109, Australia
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3
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Ghaly TM, Rajabal V, Penesyan A, Coleman NV, Paulsen IT, Gillings MR, Tetu SG. Functional enrichment of integrons: Facilitators of antimicrobial resistance and niche adaptation. iScience 2023; 26:108301. [PMID: 38026211 PMCID: PMC10661359 DOI: 10.1016/j.isci.2023.108301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/11/2023] [Accepted: 10/19/2023] [Indexed: 12/01/2023] Open
Abstract
Integrons are genetic elements, found among diverse bacteria and archaea, that capture and rearrange gene cassettes to rapidly generate genetic diversity and drive adaptation. Despite their broad taxonomic and geographic prevalence, and their role in microbial adaptation, the functions of gene cassettes remain poorly characterized. Here, using a combination of bioinformatic and experimental analyses, we examined the functional diversity of gene cassettes from different environments. We find that cassettes encode diverse antimicrobial resistance (AMR) determinants, including those conferring resistance to antibiotics currently in the developmental pipeline. Further, we find a subset of cassette functions is universally enriched relative to their broader metagenomes. These are largely involved in (a)biotic interactions, including AMR, phage defense, virulence, biodegradation, and stress tolerance. The remainder of functions are sample-specific, suggesting that they confer localised functions relevant to their microenvironment. Together, they comprise functional profiles different from bulk metagenomes, representing niche-adaptive components of the prokaryotic pangenome.
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Affiliation(s)
- Timothy M. Ghaly
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
| | - Vaheesan Rajabal
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
| | - Anahit Penesyan
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
| | - Nicholas V. Coleman
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
| | - Ian T. Paulsen
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
| | - Michael R. Gillings
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
| | - Sasha G. Tetu
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
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4
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Mahdi I, Fahsi N, Hijri M, Sobeh M. Antibiotic resistance in plant growth promoting bacteria: A comprehensive review and future perspectives to mitigate potential gene invasion risks. Front Microbiol 2022; 13:999988. [PMID: 36204627 PMCID: PMC9530320 DOI: 10.3389/fmicb.2022.999988] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/25/2022] [Indexed: 11/26/2022] Open
Abstract
Plant growth-promoting bacteria (PGPB) are endowed with several attributes that can be beneficial for host plants. They opened myriad doors toward green technology approach to reduce the use of chemical inputs, improve soil fertility, and promote plants’ health. However, many of these PGPB harbor antibiotic resistance genes (ARGs). Less attention has been given to multi-resistant bacterial bioinoculants which may transfer their ARGs to native soil microbial communities and other environmental reservoirs including animals, waters, and humans. Therefore, large-scale inoculation of crops by ARGs-harboring bacteria could worsen the evolution and dissemination of antibiotic resistance and aggravate the negative impacts on such ecosystem and ultimately public health. Their introduction into the soil could serve as ARGs invasion which may inter into the food chain. In this review, we underscore the antibiotic resistance of plant-associated bacteria, criticize the lack of consideration for this phenomenon in the screening and application processes, and provide some recommendations as well as a regulation framework relating to the development of bacteria-based biofertilizers to aid maximizing their value and applications in crop improvement while reducing the risks of ARGs invasion.
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Affiliation(s)
- Ismail Mahdi
- Agrobiosciences Research Program, Mohammed VI Polytechnic University (UM6P), Ben Guerir, Morocco
| | - Nidal Fahsi
- Agrobiosciences Research Program, Mohammed VI Polytechnic University (UM6P), Ben Guerir, Morocco
| | - Mohamed Hijri
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, QC, Canada
- African Genome Center, Mohammed VI Polytechnic University (UM6P), Ben Guerir, Morocco
- *Correspondence: Mohamed Hijri,
| | - Mansour Sobeh
- Agrobiosciences Research Program, Mohammed VI Polytechnic University (UM6P), Ben Guerir, Morocco
- Mansour Sobeh,
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5
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Responses of the Soil Bacterial Community, Resistome, and Mobilome to a Decade of Annual Exposure to Macrolide Antibiotics. Appl Environ Microbiol 2022; 88:e0031622. [PMID: 35384705 DOI: 10.1128/aem.00316-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biosolids that are applied to agricultural soil as an organic fertilizer are frequently contaminated with pharmaceutical residues that have persisted during wastewater treatment and partitioned into the organic phase. Macrolide antibiotics, which serve as a critically important human medicine, have been detected within biosolids. To determine the impacts of macrolide antibiotics on soil bacteria, every year for a decade, a series of replicated field plots received an application of a mixture of erythromycin, clarithromycin, and azithromycin at a realistic (0.1 mg kg soil-1) or an unrealistically high (10 mg kg soil-1) dose or were left untreated. The effects of repeated antibiotic exposure on the soil bacterial community, resistome, mobilome, and integron gene cassette content were evaluated by 16S rRNA and integron gene cassette amplicon sequencing, as well as whole-metagenome sequencing. At the unrealistically high dose, the overall diversity of the resistome and mobilome was altered, as 21 clinically important antibiotic resistance genes predicted to encode resistance to 10 different antibiotic drug classes were increased and 20 mobile genetic element variants (tnpA, intI1, tnpAN, and IS91) were increased. In contrast, at the realistic dose, no effect was observed on the overall diversity of the soil bacterial community, resistome, mobilome, or integron gene cassette-carrying genes. Overall, these results suggest that macrolide antibiotics entrained into soil at concentrations anticipated with biosolid applications would not result in major changes to these endpoints. IMPORTANCE Biosolids, produced from the treatment of sewage sludge, are rich in plant nutrients and are a valuable alternative to inorganic fertilizer when applied to agricultural soil. However, the use of biosolids in agriculture, which are frequently contaminated with pharmaceuticals, such as macrolide antibiotics, may pose a risk to human health by selecting for antibiotic resistance genes that could be transferred to plant-based food destined for human consumption. The consequences of long-term, repeated macrolide antibiotic exposure on the diversity of the soil bacterial community, resistome, and mobilome were evaluated. At unrealistically high concentrations, macrolide antibiotics alter the overall diversity of the resistome and mobilome, enriching for antibiotic resistance genes and mobile genetic elements of concern to human health. However, at realistic antibiotic concentrations, no effect on these endpoints was observed, suggesting that current biosolids land management practices are unlikely to pose a risk to human health due to macrolide antibiotic contamination alone.
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6
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Ghaly TM, Penesyan A, Pritchard A, Qi Q, Rajabal V, Tetu SG, Gillings MR. Methods for the targeted sequencing and analysis of integrons and their gene cassettes from complex microbial communities. Microb Genom 2022; 8. [PMID: 35298369 PMCID: PMC9176274 DOI: 10.1099/mgen.0.000788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Integrons are microbial genetic elements that can integrate mobile gene cassettes. They are mostly known for spreading antibiotic resistance cassettes among human pathogens. However, beyond clinical settings, gene cassettes encode an extraordinarily diverse range of functions important for bacterial adaptation. The recovery and sequencing of cassettes has promising applications, including: surveillance of clinically important genes, particularly antibiotic resistance determinants; investigating the functional diversity of integron-carrying bacteria; and novel enzyme discovery. Although gene cassettes can be directly recovered using PCR, there are no standardised methods for their amplification and, importantly, for validating sequences as genuine integron gene cassettes. Here, we present reproducible methods for the amplification, sequence processing, and validation of gene cassette amplicons from complex communities. We describe two different PCR assays that either amplify cassettes together with integron integrases, or gene cassettes together within cassette arrays. We compare the performance of Nanopore and Illumina sequencing, and present bioinformatic pipelines that filter sequences to ensure that they represent amplicons from genuine integrons. Using a diverse set of environmental DNAs, we show that our approach can consistently recover thousands of unique cassettes per sample and up to hundreds of different integron integrases. Recovered cassettes confer a wide range of functions, including antibiotic resistance, with as many as 300 resistance cassettes found in a single sample. In particular, we show that class one integrons are collecting and concentrating resistance genes out of the broader diversity of cassette functions. The methods described here can be applied to any environmental or clinical microbiome sample.
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Affiliation(s)
- Timothy M Ghaly
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
| | - Anahit Penesyan
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
| | - Alexander Pritchard
- Division of Food Sciences, University of Nottingham, Loughborough LE12 5RD, Australia
| | - Qin Qi
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia
| | - Vaheesan Rajabal
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
| | - Sasha G Tetu
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
| | - Michael R Gillings
- School of Natural Sciences, Macquarie University, New South Wales 2109, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, New South Wales 2109, Australia
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7
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Quintela-Baluja M, Frigon D, Abouelnaga M, Jobling K, Romalde JL, Gomez Lopez M, Graham DW. Dynamics of integron structures across a wastewater network - Implications to resistance gene transfer. WATER RESEARCH 2021; 206:117720. [PMID: 34673462 PMCID: PMC8626773 DOI: 10.1016/j.watres.2021.117720] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/14/2021] [Accepted: 09/24/2021] [Indexed: 05/19/2023]
Abstract
Class 1 and other integrons are common in wastewater networks, often being associated with antibiotic resistance genes (ARGs). However, the importance of different integron structures in ARG transfer within wastewater systems has only been implied, especially between community and hospital sources, among wastewater treatment plant compartments, and in receiving waters. This uncertainty is partly because current clinical class 1 integron qPCR assays (i.e., that target human-impacted structures, i.e., clintI1) poorly delineate clintI1 from non-impacted class 1 integron structures. They also say nothing about their ARG content. To fill these technical gaps, new real-time qPCR assays were developed for "impacted" class 1 structures (called aint1; i.e., anthropogenic class 1 integrons) and empty aint1 structures (i.e., carry no ARGs; called eaint1). The new assays and other integron assays then were used to examine integron dynamics across a wastewater network. 16S metagenomic sequencing also was performed to characterise associated microbiomes. aint1 abundances per bacterial cell were about 10 times greater in hospital wastewaters compared with other compartments, suggesting aint1 enrichment with ARGs in hospital sources. Conversely, the relative abundance of eaint1 structures were over double in recycled activated sludge compared with other compartments, except receiving waters (RAS; ∼30% of RAS class 1 structures did not carry ARGs). Microbiome analysis showed that human-associated bacterial taxa with mobile integrons also differed in RAS and river sediments. Further, class 1 integrons in RAS bacteria appear to have released ARGs, whereas hospital bacteria have accumulated ARGs. Results show that quantifying integron dynamics can help explain where ARG transfer occurs in wastewater networks, and should be considered in future studies on antibiotic resistance in the environment.
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Affiliation(s)
- Marcos Quintela-Baluja
- School of Engineering, Cassie Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; Department of Analytical Chemistry, Nutrition and Bromatology, University of Santiago de Compostela, Spain.
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, Montréal (QC), Canada
| | - M Abouelnaga
- Department of Analytical Chemistry, School of Veterinary Sciences, Suez Canel University, Ismailia, Egypt
| | - Kelly Jobling
- School of Engineering, Cassie Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Jesús L Romalde
- Departamento de Microbiología y Parasitología, CIBUS-Facultad de Biología & Institute CRETUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | | | - David W Graham
- School of Engineering, Cassie Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
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8
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Antelo V, Giménez M, Azziz G, Valdespino‐Castillo P, Falcón LI, Ruberto LAM, Mac Cormack WP, Mazel D, Batista S. Metagenomic strategies identify diverse integron-integrase and antibiotic resistance genes in the Antarctic environment. Microbiologyopen 2021; 10:e1219. [PMID: 34713606 PMCID: PMC8435808 DOI: 10.1002/mbo3.1219] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/24/2021] [Indexed: 11/08/2022] Open
Abstract
The objective of this study is to identify and analyze integrons and antibiotic resistance genes (ARGs) in samples collected from diverse sites in terrestrial Antarctica. Integrons were studied using two independent methods. One involved the construction and analysis of intI gene amplicon libraries. In addition, we sequenced 17 metagenomes of microbial mats and soil by high-throughput sequencing and analyzed these data using the IntegronFinder program. As expected, the metagenomic analysis allowed for the identification of novel predicted intI integrases and gene cassettes (GCs), which mostly encode unknown functions. However, some intI genes are similar to sequences previously identified by amplicon library analysis in soil samples collected from non-Antarctic sites. ARGs were analyzed in the metagenomes using ABRIcate with CARD database and verified if these genes could be classified as GCs by IntegronFinder. We identified 53 ARGs in 15 metagenomes, but only four were classified as GCs, one in MTG12 metagenome (Continental Antarctica), encoding an aminoglycoside-modifying enzyme (AAC(6´)acetyltransferase) and the other three in CS1 metagenome (Maritime Antarctica). One of these genes encodes a class D β-lactamase (blaOXA-205) and the other two are located in the same contig. One is part of a gene encoding the first 76 amino acids of aminoglycoside adenyltransferase (aadA6), and the other is a qacG2 gene.
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Affiliation(s)
- Verónica Antelo
- Laboratorio de Microbiología MolecularInstituto de Investigaciones Biológicas Clemente Estable (MECAv. Italia 3318MontevideoCP 11600Uruguay
| | - Matías Giménez
- Laboratorio de Microbiología MolecularInstituto de Investigaciones Biológicas Clemente Estable (MECAv. Italia 3318MontevideoCP 11600Uruguay
- Laboratorio de Genómica MicrobianaInstitut Pasteur Montevideo. Mataojo 2020MontevideoUruguay
| | - Gastón Azziz
- Laboratorio de MicrobiologíaFacultad de AgronomíaUdelaR. Av. Garzón 780. CP 12900MontevideoUruguay
| | - Patricia Valdespino‐Castillo
- Molecular Biophysics and Integrated Bioimaging DivisionBSISB ProgramLawrence Berkeley National LaboratoryOne Cyclotron RdBerkeleyCA94720USA
| | - Luisa I. Falcón
- Laboratorio de Ecología BacterianaInstituto de EcologíaUniversidad Nacional Autónoma de MéxicoCDMX04510Mexico
- UNAMParque Científico y Tecnológico de Yucatán97302Mexico
| | - Lucas A. M. Ruberto
- Instituto Antártico Argentino. Av25 de Mayo 1143San Martín, Buenos Aires1650Argentina
- Cátedra de BiotecnologíaFacultad de Farmacia y Bioquímica e Instituto Nanobiotec UBA‐CONICET. Ave. Junín 956Buenos Aires1113Argentina
| | - Walter P. Mac Cormack
- Instituto Antártico Argentino. Av25 de Mayo 1143San Martín, Buenos Aires1650Argentina
- Cátedra de BiotecnologíaFacultad de Farmacia y Bioquímica e Instituto Nanobiotec UBA‐CONICET. Ave. Junín 956Buenos Aires1113Argentina
| | - Didier Mazel
- Département Génomes et GénétiqueInstitut PasteurUnité Plasticité du Génome BactérienParisFrance
- CNRSUMR3525ParisFrance
| | - Silvia Batista
- Laboratorio de Microbiología MolecularInstituto de Investigaciones Biológicas Clemente Estable (MECAv. Italia 3318MontevideoCP 11600Uruguay
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Lundbäck IC, McDougall FK, Dann P, Slip DJ, Gray R, Power ML. Into the sea: Antimicrobial resistance determinants in the microbiota of little penguins (Eudyptula minor). INFECTION GENETICS AND EVOLUTION 2020; 88:104697. [PMID: 33370595 DOI: 10.1016/j.meegid.2020.104697] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/11/2020] [Accepted: 12/22/2020] [Indexed: 12/30/2022]
Abstract
Terrestrial and aquatic birds have been proposed as sentinels for the spread of antimicrobial resistant bacteria, but few species have been investigated specifically in the context of AMR in the marine ecosystem. This study contrasts the occurrence of class 1 integrons and associated antimicrobial resistance genes in wild and captive little penguins (Eudyptula minor), an Australian seabird with local population declines. PCR screening of faecal samples (n = 448) revealed a significant difference in the prevalence of class 1 integrons in wild and captive groups, 3.2% and 44.7% respectively, with genes that confer resistance to streptomycin, spectinomycin, trimethoprim and multidrug efflux pumps detected. Class 1 integrons were not detected in two clinically relevant bacterial species, Klebsiella pneumoniae or Escherichia coli, isolated from penguin faeces. The presence of class 1 integrons in the little penguin supports the use of marine birds as sentinels of AMR in marine environments.
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Affiliation(s)
- Ida C Lundbäck
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, Australia
| | - Fiona K McDougall
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, Australia
| | - Peter Dann
- Conservation Department, Phillip Island Nature Parks, Victoria, Australia
| | - David J Slip
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, Australia; Taronga Conservation Society, Sydney, Australia
| | - Rachael Gray
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Australia
| | - Michelle L Power
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, Australia.
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10
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Zhang X, Li X, Wang W, Qi J, Wang D, Xu L, Liu Y, Zhang Y, Guo K. Diverse Gene Cassette Arrays Prevail in Commensal Escherichia coli From Intensive Farming Swine in Four Provinces of China. Front Microbiol 2020; 11:565349. [PMID: 33154738 PMCID: PMC7591504 DOI: 10.3389/fmicb.2020.565349] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/01/2020] [Indexed: 12/14/2022] Open
Abstract
Multiple-drug resistance bacteria containing antimicrobial resistance genes (ARGs) are a concern for public health. Integrons are bacterial genetic elements that can capture, rearrange, and express mobile gene cassettes responsible for the spread of ARGs. Few studies link genotype and phenotype of swine-related ARGs in the context of mobile gene cassette arrays among commensal Escherichia coli (E. coli) in nonclinical livestock isolates from intensive farms. In the present study, a total of 264 isolates were obtained from 330 rectal swabs to determine the prevalence and characteristics of antibiotic-resistant gene being carried by commensal E. coli in the healthy swine from four intensive farms at Anhui, Hebei, Shanxi, and Shaanxi, in China. Antimicrobial resistance phenotypes of the recovered isolates were determined for 19 antimicrobials. The E. coli isolates were commonly nonsusceptible to doxycycline (75.8%), tetracycline (73.5%), sulfamethoxazole-trimethoprim (71.6%), amoxicillin (68.2%), sulfasalazine (67.1%), ampicillin (58.0%), florfenicol (56.1%), and streptomycin (53.0%), but all isolates were susceptible to imipenem (100%). Isolates [184 (69.7%)] exhibited multiple drug resistance with 11 patterns. Moreover, 197 isolates (74.6%) were detected carrying the integron-integrase gene (intI1) of class 1 integrons. A higher incidence of antimicrobial resistance was observed in the intI1-positive E. coli isolates than in the intI1-negative E. coli isolates. Furthermore, there were 17 kinds of gene cassette arrays in the 70 integrons as detected by sequencing amplicons of variable regions, with 66 isolates (94.3%) expressing their gene cassettes encoding for multiple drug resistance phenotypes for streptomycin, neomycin, gentamicin, kanamycin, amikacin, sulfamethoxazole-trimethoprim, sulfasalazine, and florfenicol. Notably, due to harboring multiple, hybrid, and recombination cassettes, complex cassette arrays were attributed to multiple drug resistance patterns than simple arrays. In conclusion, we demonstrated that the prevalence of multiple drug resistance and the incidence of class 1 integrons were 69.7 and 74.6% in commensal E. coli isolated from healthy swine, which were lower in frequency than that previously reported in China.
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Affiliation(s)
- Xiuping Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China.,College of Animal Science, Tarim University, Alar, China
| | - Xinxin Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Weihua Wang
- Weinan Vocational and Technical College, Weinan, China
| | - Jiali Qi
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Dong Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Lei Xu
- College of Life Science, Northwest A&F University, Yangling, China
| | - Yong Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Yanming Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Kangkang Guo
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
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11
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Ali N, Lin Y, Qing Z, Xiao D, Ud Din A, Ali I, Lian T, Chen B, Wen R. The Role of Agriculture in the Dissemination of Class 1 Integrons, Antimicrobial Resistance, and Diversity of Their Gene Cassettes in Southern China. Genes (Basel) 2020; 11:genes11091014. [PMID: 32872161 PMCID: PMC7564866 DOI: 10.3390/genes11091014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 12/15/2022] Open
Abstract
Integrons are hot spots for acquiring gene cassettes from the environment and play a major role in the bacterial evolution and dissemination of antimicrobial resistance (AMR), thus posing a serious threat. There are currently studies on integrons and antibiotic resistance genes; however, the presence and association of integrons in different agricultural crops and their subsequent dissemination and role in AMR have not been reported previously. This study examines the abundance of integrons, their gene cassette diversity in various crop soils, and their role in the dissemination of AMR in the southern region of China. Samples from different agri-crop soil, such as rice (R.S), sugarcane (S.S), citrus (C.S), banana (B.S), agricultural runoff (the point where the runoff of all sites meet (R.O)), and wild (non-agricultural) soil (W.S), were collected. Quantitative PCR was used to determine the abundance of integrons, and clone libraries were constructed to examine the gene cassette arrays. All the tested samples were found positive for Class-I (CL1) integrons and revealed a higher concentration and higher relative abundance of R.S than the others, with the least found at the W.S site. The W.S CL1 cassette arrays were found empty, and no putative conserved domains were found. The R.O was found to contain a high number of gene cassettes with various functions, while the smallest number of gene cassettes was found in the S.S among the crop soils. Most of the gene cassettes presented by the R.O were primarily shared with other sites, and the antibiotic-resistant genes were consistently observed to be dominant. The constructed clone libraries represented a diverse gene cassette array with 16% novel gene cassettes that play a vital role in pathogenesis, transportation, biosynthesis, and AMR. Most resistance-related gene cassettes were associated with the genes encoding resistance to quaternary ammonium compound (QAC) and aminoglycosides. This study highlights the significant differences in the abundance of integrons among various agricultural soils and offers deep insight into the pools of gene cassettes that play a key role in the dissemination of integrons and AMR.
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Affiliation(s)
- Niyaz Ali
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Yinfu Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Zhen Qing
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Dan Xiao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Ahmad Ud Din
- Drug Discovery Research Center, South West Medical University, Luzhou 646000, China;
| | - Izhar Ali
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
| | - Tengxiang Lian
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, South China Agricultural University, Guangzhou 510642, China;
| | - Baoshan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
- Guangxi Key Lab for Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Ronghui Wen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bio-Resources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (N.A.); (Y.L.); (Z.Q.); (D.X.); (I.A.); (B.C.)
- Correspondence: ; Tel.: +86-13669614062
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12
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Buongermino Pereira M, Österlund T, Eriksson KM, Backhaus T, Axelson-Fisk M, Kristiansson E. A comprehensive survey of integron-associated genes present in metagenomes. BMC Genomics 2020; 21:495. [PMID: 32689930 PMCID: PMC7370490 DOI: 10.1186/s12864-020-06830-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 06/15/2020] [Indexed: 12/19/2022] Open
Abstract
Background Integrons are genomic elements that mediate horizontal gene transfer by inserting and removing genetic material using site-specific recombination. Integrons are commonly found in bacterial genomes, where they maintain a large and diverse set of genes that plays an important role in adaptation and evolution. Previous studies have started to characterize the wide range of biological functions present in integrons. However, the efforts have so far mainly been limited to genomes from cultivable bacteria and amplicons generated by PCR, thus targeting only a small part of the total integron diversity. Metagenomic data, generated by direct sequencing of environmental and clinical samples, provides a more holistic and unbiased analysis of integron-associated genes. However, the fragmented nature of metagenomic data has previously made such analysis highly challenging. Results Here, we present a systematic survey of integron-associated genes in metagenomic data. The analysis was based on a newly developed computational method where integron-associated genes were identified by detecting their associated recombination sites. By processing contiguous sequences assembled from more than 10 terabases of metagenomic data, we were able to identify 13,397 unique integron-associated genes. Metagenomes from marine microbial communities had the highest occurrence of integron-associated genes with levels more than 100-fold higher than in the human microbiome. The identified genes had a large functional diversity spanning over several functional classes. Genes associated with defense mechanisms and mobility facilitators were most overrepresented and more than five times as common in integrons compared to other bacterial genes. As many as two thirds of the genes were found to encode proteins of unknown function. Less than 1% of the genes were associated with antibiotic resistance, of which several were novel, previously undescribed, resistance gene variants. Conclusions Our results highlight the large functional diversity maintained by integrons present in unculturable bacteria and significantly expands the number of described integron-associated genes.
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Affiliation(s)
- Mariana Buongermino Pereira
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden
| | - Tobias Österlund
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden
| | - K Martin Eriksson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.,Gothenburg Centre for Sustainable Development, Chalmers University of Technology, Gothenburg, Sweden
| | - Thomas Backhaus
- Centre for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden.,Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Marina Axelson-Fisk
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Erik Kristiansson
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden. .,Centre for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden.
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13
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The Peril and Promise of Integrons: Beyond Antibiotic Resistance. Trends Microbiol 2020; 28:455-464. [PMID: 31948729 DOI: 10.1016/j.tim.2019.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/13/2019] [Accepted: 12/09/2019] [Indexed: 12/11/2022]
Abstract
Integrons are bacterial genetic elements that can capture, rearrange, and express mobile gene cassettes. They are best known for their role in disseminating antibiotic-resistance genes among pathogens. Their ability to rapidly spread resistance phenotypes makes it important to consider what other integron-mediated traits might impact human health in the future, such as increased virulence, pathogenicity, or resistance to novel antimicrobial strategies. Exploring the functional diversity of cassettes and understanding their de novo creation will allow better pre-emptive management of bacterial growth, while also facilitating development of technologies that could harness integron activity. If we can control integrons and cassette formation, we could use integrons as a platform for enzyme discovery and to construct novel biochemical pathways, with applications in bioremediation or biosynthesis of industrial and therapeutic molecules. Integron activity thus holds both peril and promise for humans.
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14
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Shen JP, Li ZM, Hu HW, Zeng J, Zhang LM, Du S, He JZ. Distribution and Succession Feature of Antibiotic Resistance Genes Along a Soil Development Chronosequence in Urumqi No.1 Glacier of China. Front Microbiol 2019; 10:1569. [PMID: 31354668 PMCID: PMC6629927 DOI: 10.3389/fmicb.2019.01569] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 06/24/2019] [Indexed: 01/03/2023] Open
Abstract
Primary succession of plant and microbial communities in the glacier retreating foreland has been extensively studied, but shifts of antibiotic resistance genes (ARGs) with the glacier retreating due to global warming remain elusive. Unraveling the diversity and succession features of ARGs in pristine soil during glacier retreating could contribute to a mechanistic understanding of the evolution and development of soil resistome. In this study, we quantified the abundance and diversity of ARGs along a 50-year soil development chronosequence by using a high-throughput quantitative PCR (HT-qPCR) technique. A total of 24 ARGs and two mobile genetic elements (MGEs) were detected from all the glacier samples, and the numbers of detected ARGs showed a unimodal pattern with an increasing trend at the early stage (0∼8 years) but no significant change at later stages (17∼50 years). The oprJ and mexF genes encoding multidrug resistance were the only two ARGs that were detected across all the succession ages, and the mexF gene showed an increasing trend along the succession time. Structural equation models indicated the predominant role of the intI1 gene encoding the Class 1 integron-integrase in shaping the variation of ARG profiles. These findings suggested the presence of ARGs in pristine soils devoid of anthropogenic impacts, and horizontal gene transfer mediated by MGEs may contribute to the succession patterns of ARGs during the initial soil formation stage along the chronosequence.
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Affiliation(s)
- Ju-Pei Shen
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Zong-Ming Li
- College of Animal Science, Yangtze University, Jingzhou, China
| | - Hang-Wei Hu
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia.,School of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Jun Zeng
- Institute of Applied Microbiology, Xinjiang Academy of Agricultural Sciences, Ürümqi, China
| | - Li-Mei Zhang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Shuai Du
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Ji-Zheng He
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia
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15
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Tansirichaiya S, Mullany P, Roberts AP. Promoter activity of ORF-less gene cassettes isolated from the oral metagenome. Sci Rep 2019; 9:8388. [PMID: 31182805 PMCID: PMC6557892 DOI: 10.1038/s41598-019-44640-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 05/17/2019] [Indexed: 01/09/2023] Open
Abstract
Integrons are genetic elements consisting of a functional platform for recombination and expression of gene cassettes (GCs). GCs usually carry promoter-less open reading frames (ORFs), encoding proteins with various functions including antibiotic resistance. The transcription of GCs relies mainly on a cassette promoter (PC), located upstream of an array of GCs. Some integron GCs, called ORF-less GCs, contain no identifiable ORF with a small number shown to be involved in antisense mRNA mediated gene regulation. In this study, the promoter activity of ORF-less GCs, previously recovered from the oral metagenome, was verified by cloning them upstream of a gusA reporter, proving they can function as a promoter, presumably allowing bacteria to adapt to multiple stresses within the complex physico-chemical environment of the human oral cavity. A bi-directional promoter detection system was also developed allowing direct identification of clones with promoter-containing GCs on agar plates. Novel promoter-containing GCs were identified from the human oral metagenomic DNA using this construct, called pBiDiPD. This is the first demonstration and detection of promoter activity of ORF-less GCs from Treponema bacteria and the development of an agar plate-based detection system will enable similar studies in other environments.
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Affiliation(s)
- Supathep Tansirichaiya
- Department of Microbial Diseases, University College London, Eastman Dental Institute, 256 Gray's Inn Road, London, WC1X 8LD, UK.,Department of Clinical Dentistry, Faculty of Health Sciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Peter Mullany
- Department of Microbial Diseases, University College London, Eastman Dental Institute, 256 Gray's Inn Road, London, WC1X 8LD, UK
| | - Adam P Roberts
- Department of Microbial Diseases, University College London, Eastman Dental Institute, 256 Gray's Inn Road, London, WC1X 8LD, UK. .,Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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16
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Ghaly TM, Geoghegan JL, Alroy J, Gillings MR. High diversity and rapid spatial turnover of integron gene cassettes in soil. Environ Microbiol 2019; 21:1567-1574. [PMID: 30724441 DOI: 10.1111/1462-2920.14551] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 01/30/2019] [Indexed: 12/01/2022]
Abstract
Integrons are genetic elements that promote rapid adaptation in bacteria by capturing exogenous, mobile gene cassettes. Recently, a subset of gene cassettes has facilitated the global spread of antibiotic resistance. However, outside clinical settings, very little is known about their diversity and spatial ecology. To address this question, we sequenced integron gene cassettes from soils sampled across Australia and Antarctica. We recovered 44 970 open reading frames that encoded 27 215 unique proteins, representing an order of magnitude more cassettes than previous sequencing efforts. We found that cassettes have extremely high local richness, significantly greater than previously predicted, with estimates ranging from 4000 to 18 000 unique cassettes per 0.3 g of soil. We show that cassettes have a heterogeneous distribution across space, and that they exhibit rapid turnover with distance. Similarity between samples drops to between 0.1% and 10% at distances of as little as 100 m. Together, these data provide key insights into the ecology and size of the gene cassette metagenome.
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Affiliation(s)
- Timothy M Ghaly
- Department of Biological Science, Macquarie University, Sydney, NSW, 2109, Australia
| | - Jemma L Geoghegan
- Department of Biological Science, Macquarie University, Sydney, NSW, 2109, Australia
| | - John Alroy
- Department of Biological Science, Macquarie University, Sydney, NSW, 2109, Australia
| | - Michael R Gillings
- Department of Biological Science, Macquarie University, Sydney, NSW, 2109, Australia
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17
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Gatica J, Tripathi V, Green S, Manaia CM, Berendonk T, Cacace D, Merlin C, Kreuzinger N, Schwartz T, Fatta-Kassinos D, Rizzo L, Schwermer CU, Garelick H, Jurkevitch E, Cytryn E. High Throughput Analysis of Integron Gene Cassettes in Wastewater Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:11825-11836. [PMID: 27689892 DOI: 10.1021/acs.est.6b03188] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Integrons are extensively targeted as a proxy for anthropogenic impact in the environment. We developed a novel high-throughput amplicon sequencing pipeline that enables characterization of thousands of integron gene cassette-associated reads, and applied it to acquire a comprehensive overview of gene cassette composition in effluents from wastewater treatment facilities across Europe. Between 38 100 and 172 995 reads per-sample were generated and functionally characterized by screening against nr, SEED, ARDB and β-lactamase databases. Over 75% of the reads were characterized as hypothetical, but thousands were associated with toxin-antitoxin systems, DNA repair, cell membrane function, detoxification and aminoglycoside and β-lactam resistance. Among the reads characterized as β-lactamases, the carbapenemase blaOXA was dominant in most of the effluents, except for Cyprus and Israel where blaGES was also abundant. Quantitative PCR assessment of blaOXA and blaGES genes in the European effluents revealed similar trends to those displayed in the integron amplicon sequencing pipeline described above, corroborating the robustness of this method and suggesting that these integron-associated genes may be excellent targets for source tracking of effluents in downstream environments. Further application of the above analyses revealed several order-of-magnitude reductions in effluent-associated β-lactamase genes in effluent-saturated soils, suggesting marginal persistence in the soil microbiome.
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Affiliation(s)
- Joao Gatica
- The Institute of Soil, Water and Environmental Sciences, The Volcani Center, Agricultural Research Organization, Bet-Dagan, Israel
- The Department of Soil and Water Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot, Israel
| | - Vijay Tripathi
- The Department of Soil and Water Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot, Israel
| | - Stefan Green
- DNA Services Facility, Research Resources Center, University of Illinois at Chicago , Chicago, Illinois 60612, United States
| | - Celia M Manaia
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa , Lisboa, Portugal
| | - Thomas Berendonk
- Faculty of Environmental Sciences, Technische Universität Dresden , Dresden, Germany
| | - Damiano Cacace
- Faculty of Environmental Sciences, Technische Universität Dresden , Dresden, Germany
| | - Christophe Merlin
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol , 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France
- Université de Lorraine, LCPME , UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France
| | - Norbert Kreuzinger
- Institute for Water Quality, Resources and Waste Managment, Technische Universität Wien , Wien, Austria
| | - Thomas Schwartz
- Karlsruhe Institute of Technology , Eggenstein-Leopoldshafen, Germany
| | - Despo Fatta-Kassinos
- Department of Civil and Environmental Engineering and Nireas, International Water Research Center, University of Cyprus , P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Luigi Rizzo
- Department of Civil Engineering, University of Salerno , Salerno, Italy
| | | | - Hemda Garelick
- School of Science and Technology, Middlesex University , London, U.K
| | - Edouard Jurkevitch
- The Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , Rehovot, Israel
| | - Eddie Cytryn
- The Institute of Soil, Water and Environmental Sciences, The Volcani Center, Agricultural Research Organization, Bet-Dagan, Israel
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18
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Upadhyay S, Joshi SR. TEM mediated extended spectrum cephalosporin resistance in clinical & environmental isolates of Gram negative bacilli: A report from northeast India. Indian J Med Res 2016; 142:614-7. [PMID: 26658599 PMCID: PMC4743351 DOI: 10.4103/0971-5916.171294] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
| | - S R Joshi
- Microbiology Laboratory, Department of Biotechnology & Bioinformatics, North Eastern Hill University, Shillong 793 022, Meghalaya, India
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19
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Gillings MR, Paulsen IT, Tetu SG. Genomics and the evolution of antibiotic resistance. Ann N Y Acad Sci 2016; 1388:92-107. [DOI: 10.1111/nyas.13268] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/06/2016] [Indexed: 12/21/2022]
Affiliation(s)
| | - Ian T. Paulsen
- Department of Chemistry and Biomolecular Sciences; Macquarie University; Sydney Australia
| | - Sasha G. Tetu
- Department of Chemistry and Biomolecular Sciences; Macquarie University; Sydney Australia
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20
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Patterson SK, Singer RS. Development of a Polymerase Chain Reaction Assay for the Detection of Antibiotic Resistance Genes in Community DNA. J Vet Diagn Invest 2016; 18:172-81. [PMID: 16617698 DOI: 10.1177/104063870601800206] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Many methods are used to detect antibiotic resistance genes in samples. The objective of the study reported here was to compare polymerase chain reaction (PCR) analysis of community DNA with fecal culturing for detecting antibiotic resistance genes in cattle samples. In the laboratory-based portion of this study, known concentrations of an Escherichia coli strain with 3 antibiotic resistance genes ( cmy-2, flo, and cat) were added to feces from dairy cattle. These genes were used to assess the effect of various primer pairs, chromosomally versus plasmid-encoded genes, and gene copy number on the sensitivity of PCR amplification. Gene-specific PCR amplification was performed on the community DNA extracted from the feces. Feces were cultured for the inoculated strain. In the field-based portion of the study, 80 cattle fecal samples of unknown gene status were compared by use of similar methods. Culture and PCR amplification from community DNA extractions produced variable results, and this variability was most noticeable at dilutions that approached the detection limit of the assay. Typically, PCR amplification had a higher sensitivity than did culture for detecting the gene of interest. However, the sensitivity of culture was improved by plating on selective media containing antibiotics. The community DNA approach enables assessment of bacterial communities in complex samples such as feces, a task that can be prohibitive by budget or time constraints associated with culture methods. Through a strategic combination of culture and community DNA approaches, the relationship between specific selection pressures and the persistence and dissemination of specific resistance genes can be elucidated.
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Affiliation(s)
- Sheila K Patterson
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana 61802, USA
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21
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Detection of Novel Integrons in the Metagenome of Human Saliva. PLoS One 2016; 11:e0157605. [PMID: 27304457 PMCID: PMC4909258 DOI: 10.1371/journal.pone.0157605] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/01/2016] [Indexed: 01/08/2023] Open
Abstract
Integrons are genetic elements capable of capturing and expressing open reading frames (ORFs) embedded within gene cassettes. They are involved in the dissemination of antibiotic resistance genes (ARGs) in clinically important pathogens. Although the ARGs are common in the oral cavity the association of integrons and antibiotic resistance has not been reported there. In this work, a PCR-based approach was used to investigate the presence of integrons and associated gene cassettes in human oral metagenomic DNA obtained from both the UK and Bangladesh. We identified a diverse array of gene cassettes containing ORFs predicted to confer antimicrobial resistance and other adaptive traits. The predicted proteins include a putative streptogramin A O-acetyltransferase, a bleomycin binding protein, cof-like hydrolase, competence and motility related proteins. This is the first study detecting integron gene cassettes directly from oral metagenomic DNA samples. The predicted proteins are likely to carry out a multitude of functions; however, the function of the majority is yet unknown.
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22
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Maurya AP, Choudhury D, Talukdar AD, Dhar Chanda D, Chakravarty A, Bhattacharjee A. Emergence of integron borne PER-1 mediated extended spectrum cephalosporin resistance among nosocomial isolates of Gram-negative bacilli. Indian J Med Res 2016. [PMID: 26205025 PMCID: PMC4525407 DOI: 10.4103/0971-5916.160718] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Background & objectives: Pseudomonas extended resistant (PER) enzymes are rare type of extended-spectrum beta lactamases (ESBLs) that confer third generation cephalosporin resistance. These are often integron borne and laterally transmitted. The aim of the present study was to investigate the emergence of integron borne cephalosporin resistant PER-1 gene in diverse incompatibility (Inc) group plasmids among Gram-negative bacteria. Methods: A total of 613 consecutive, non-duplicate, Gram-negative bacteria of Enterobacteriaceae family and non-fermenting Gram-negative bacteria were isolated from different clinical specimens during a period of 18 months. For amplification and detection of blaPER, multiplex PCR was done. For understanding the genetic environment of blaPER-1, integrase gene PCR and cassette PCR (59 be) was performed. Gene transferability experiment was carried out and PCR based replicon typing was performed for incompatibility group typing of plasmids using 18 pairs of primers. An inhibitor based method was used for phenotypic detection of intrinsic resistance. Results: Multiplex PCR and sequencing confirmed that 45 isolates were harbouring blaPER-1. Both class 1 and class 2 integrons were observed among them. Integrase and cassette PCR (59 be) PCR results confirmed that the resistant determinant was located within class 1 integron. Transformation and conjugation experiments revealed that PER-1 was laterally transferable and disseminated through diverse Inc plasmid type. Efflux pump mediated carbapenem resistance was observed in all isolates. All isolates belonged to heterogenous groups. Interpretation & conclusions: This study demonstrates the dissemination of cephalosporins resistant, integron borne blaPER-1 in hospital setting in this part of the country and emphasizes on the rational use of third generation cephalosporins to slow down the expansion of this rare type of ESBL gene.
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23
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Abstract
The integron is a powerful system which, by capturing, stockpiling, and rearranging new functions carried by gene encoding cassettes, confers upon bacteria a rapid adaptation capability in changing environments. Chromosomally located integrons (CI) have been identified in a large number of environmental Gram-negative bacteria. Integron evolutionary history suggests that these sedentary CIs acquired mobility among bacterial species through their association with transposable elements and conjugative plasmids. As a result of massive antibiotic use, these so-called mobile integrons are now widespread in clinically relevant bacteria and are considered to be the principal agent in the emergence and rise of antibiotic multiresistance in Gram-negative bacteria. Cassette rearrangements are catalyzed by the integron integrase, a site-specific tyrosine recombinase. Central to these reactions is the single-stranded DNA nature of one of the recombination partners, the attC site. This makes the integron a unique recombination system. This review describes the current knowledge on this atypical recombination mechanism, its implications in the reactions involving the different types of sites, attC and attI, and focuses on the tight regulation exerted by the host on integron activity through the control of attC site folding. Furthermore, cassette and integrase expression are also highly controlled by host regulatory networks and the bacterial stress (SOS) response. These intimate connections to the host make the integron a genetically stable and efficient system, granting the bacteria a low cost, highly adaptive evolution potential "on demand".
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Oliveira-Pinto C, Costa PS, Reis MP, Chartone-Souza E, Nascimento AMA. Diversity of gene cassettes and the abundance of the class 1 integron-integrase gene in sediment polluted by metals. Extremophiles 2016; 20:283-9. [PMID: 26961777 DOI: 10.1007/s00792-016-0820-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 02/23/2016] [Indexed: 11/25/2022]
Abstract
The integron-gene cassette system has typically been associated with antibiotic-resistant pathogens. However, the diversity of gene cassettes and the abundance of class 1 integrons outside of the clinical context are not fully explored. Primers targeting the conserved segments of attC recombination sites were used to amplify gene cassettes from the sediment of the Mina stream, which exhibited a higher degree of stress to metal pollution in the dry season than the rainy season. Of the 143 total analyzed sequences, 101 had no matches to proteins in the database, where cassette open reading frames could be identified by homology with database entries. There was a predominance of sequences encoding essential cellular functions. Each season that was sampled yielded a specific pool of gene cassettes. Real-time PCR revealed that 8.5 and 41.6 % of bacterial cells potentially harbored a class 1 integron in the rainy and dry seasons, respectively. In summary, our findings demonstrate that most of the gene cassettes have no ascribable function and, apparently, historically metal-contaminated sediment favors the maintenance of bacteria containing the intI1 gene. Thus, the diversity of gene cassettes is far from being fully explored deserving further attention.
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Affiliation(s)
- Clarisse Oliveira-Pinto
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Patrícia S Costa
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Mariana P Reis
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Edmar Chartone-Souza
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Andréa M A Nascimento
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
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Paul D, Dhar Chanda D, Maurya AP, Mishra S, Chakravarty A, Sharma GD, Bhattacharjee A. Co-Carriage of blaKPC-2 and blaNDM-1 in Clinical Isolates of Pseudomonas aeruginosa Associated with Hospital Infections from India. PLoS One 2015; 10:e0145823. [PMID: 26714034 PMCID: PMC4694648 DOI: 10.1371/journal.pone.0145823] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022] Open
Abstract
Global spread of KPC poses to be a serious threat complicating treatment options in hospital settings. The present study investigates the genetic environment of blaKPC-2 among clinical isolates of Pseudomonas aeruginosa from a tertiary referral hospital of India. The study isolates were collected from different wards and clinics of Silchar Medical College and Hospital, India, from 2012–2013. The presence of blaKPC was confirmed by genotypic characterization followed by sequencing. Cloning of the blaKPC-2 gene was performed and the genetic environment of this gene was characterized as well. Transferability of the resistance gene was determined by transformation assay and Southern hybridization. Additionally, restriction mapping was also carried out. Two isolates of P. aeruginosa were found to harbor blaKPC-2, were resistant towards aminoglycosides, quinolone and β-lactam-β-lactamase inhibitor combination. In both the isolates, the resistance determinant was associated with class 1 integron and horizontally transferable. Both the isolates were co-harboring blaNDM-1. The first detection of this integron mediated blaKPC-2 coexisting with blaNDM-1 in P. aeruginosa from India is worrisome, and further investigation is required to track the gene cassette mediated blaKPC-2 in terms of infection control and to prevent the spread of this gene in hospitals as well as in the community.
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Affiliation(s)
- Deepjyoti Paul
- Department of Microbiology, Assam University, Silchar, India
| | | | | | - Shweta Mishra
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Atanu Chakravarty
- Department of Microbiology, Silchar Medical College and Hospital, Silchar, India
| | - Gauri Dutt Sharma
- Department of Life science and Bioinformatics, Assam University, Silchar, India
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Abella J, Fahy A, Duran R, Cagnon C. Integron diversity in bacterial communities of freshwater sediments at different contamination levels. FEMS Microbiol Ecol 2015; 91:fiv140. [DOI: 10.1093/femsec/fiv140] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/29/2022] Open
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Abella J, Bielen A, Huang L, Delmont TO, Vujaklija D, Duran R, Cagnon C. Integron diversity in marine environments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015. [PMID: 26213132 DOI: 10.1007/s11356-015-5085-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Integrons are bacterial genetic elements known to be active vectors of antibiotic resistance among clinical bacteria. They are also found in bacterial communities from natural environments. Although integrons have become especially efficient for bacterial adaptation in the particular context of antibiotic usage, their role in natural environments in other contexts is still unknown. Indeed, most studies have focused on integrons and the spread of antibiotic resistance in freshwater or soil impacted by anthropogenic activities, with only few on marine environments. Notably, integrons show a wider diversity of both gene cassettes and integrase gene in natural environments than in clinical environments, suggesting a general role of integrons in bacterial adaptation. This article reviews the current knowledge on integrons in marine environments. We also present conclusions of our studies on polluted and nonpolluted backgrounds.
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Affiliation(s)
- Justine Abella
- Equipe Environnement et Microbiologie, MELODY Group, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau, Cedex, France
| | - Ana Bielen
- Laboratory for Molecular Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000, Zagreb, Croatia
- Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, 10000, Zagreb, Croatia
| | - Lionel Huang
- Equipe Environnement et Microbiologie, MELODY Group, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau, Cedex, France
- Euro Engineering, Technopole Hélioparc Bât Newton, 4 rue Jules Ferry, CS N 99207, 64053, Pau, Cedex 09, France
| | - Tom O Delmont
- Equipe Environnement et Microbiologie, MELODY Group, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau, Cedex, France
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biology Laboratory, Woods Hole, MA, USA
| | - Dušica Vujaklija
- Laboratory for Molecular Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000, Zagreb, Croatia
| | - Robert Duran
- Equipe Environnement et Microbiologie, MELODY Group, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau, Cedex, France
| | - Christine Cagnon
- Equipe Environnement et Microbiologie, MELODY Group, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau, Cedex, France.
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Upadhyay S, Hussain A, Mishra S, Maurya AP, Bhattacharjee A, Joshi SR. Genetic Environment of Plasmid Mediated CTX-M-15 Extended Spectrum Beta-Lactamases from Clinical and Food Borne Bacteria in North-Eastern India. PLoS One 2015; 10:e0138056. [PMID: 26361395 PMCID: PMC4567302 DOI: 10.1371/journal.pone.0138056] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 08/24/2015] [Indexed: 01/09/2023] Open
Abstract
Background The study investigated the presence of CTX-M-15 type extended spectrum beta-lactamases (ESBL), compared their genetic arrangements and plasmid types in gram negative isolates of hospital and food origin in north-east India. From September 2013 to April 2014, a total of 252 consecutive, non-duplicate clinical isolates and 88 gram negative food isolates were selected. Phenotypic and molecular characterization of ESBL genes was performed. Presence of integrons and gene cassettes were analyzed by integrase and 59 base-element PCR respectively. The molecular environments surrounding blaCTX-M and plasmid types were investigated by PCR and PCR-based replicon typing respectively. Transformation was carried out to assess plasmid transfer. Southern blotting was conducted to localize the blaCTX-M-15 genes. DNA fingerprinting was performed by ERIC-PCR. Results Prevalence of ESBL was found to be 40.8% (103/252) in clinical and 31.8% (28/88) in food-borne isolates. Molecular characterization revealed the presence of 56.3% (58/103) and 53.5% (15/28) blaCTX-M-15 in clinical and food isolates respectively. Strains of clinical and food origin were non-clonal. Replicon typing revealed that IncI1 and IncFII plasmid were carrying blaCTX-M-15 in clinical and food isolates and were horizontally transferable. The ISEcp1 element was associated with blaCTX-M-15 in both clinical and food isolates. Conclusions The simultaneous presence of resistance determinants in non-clonal isolates of two different groups thus suggests that the microbiota of common food products consumed may serve as a reservoir for some of the drug resistance genes prevalent in human pathogens.
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Affiliation(s)
- Supriya Upadhyay
- Department of Biotechnology & Bioinformatics, North Eastern Hill University, Shillong, Meghalaya, India
| | - Abbas Hussain
- Department of Biotechnology & Bioinformatics, North Eastern Hill University, Shillong, Meghalaya, India
| | - Shweta Mishra
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | | | | | - Santa Ram Joshi
- Department of Biotechnology & Bioinformatics, North Eastern Hill University, Shillong, Meghalaya, India
- * E-mail:
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Maurya AP, Talukdar AD, Dhar Chanda D, Chakravarty A, Bhattacharjee A. Genetic environment of OXA-2 beta-lactamase producing Gram-negative bacilli from a tertiary referral hospital. Indian J Med Res 2015; 141:368-9. [PMID: 25963501 PMCID: PMC4442339 DOI: 10.4103/0971-5916.156584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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MOLECULAR DETECTION OF ANTIBIOTIC-RESISTANCE DETERMINANTS IN ESCHERICHIA COLI ISOLATED FROM THE ENDANGERED AUSTRALIAN SEA LION (NEOPHOCA CINEREA). J Wildl Dis 2015; 51:555-63. [PMID: 25919463 DOI: 10.7589/2014-08-200] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Greater interaction between humans and wildlife populations poses significant risks of anthropogenic impact to natural ecosystems, especially in the marine environment. Understanding the spread of microorganisms at the marine interface is therefore important if we are to mitigate adverse effects on marine wildlife. We investigated the establishment of Escherichia coli in the endangered Australian sea lion (Neophoca cinerea) by comparing fecal isolation from wild and captive sea lion populations. Fecal samples were collected from wild colonies March 2009-September 2010 and from captive individuals March 2011-May 2013. Using molecular screening, we assigned a phylotype to E. coli isolates and determined the presence of integrons, mobile genetic elements that capture gene cassettes conferring resistance to antimicrobial agents common in fecal coliforms. Group B2 was the most abundant phylotype in all E. coli isolates (n = 37), with groups A, B1, and D also identified. Integrons were not observed in E. coli (n = 21) isolated from wild sea lions, but were identified in E. coli from captive animals (n = 16), from which class I integrases were detected in eight isolates. Sequencing of gene cassette arrays identified genes conferring resistance to streptomycin-spectinomycin (aadA1) and trimethoprim (dfrA17, dfrB4). Class II integrases were not detected in the E. coli isolates. The frequent detection in captive sea lions of E. coli with resistance genes commonly identified in human clinical cases suggests that conditions experienced in captivity may contribute to establishment. Identification of antibiotic resistance in the microbiota of Australian sea lions provides crucial information for disease management. Our data will inform conservation management strategies and provide a mechanism to monitor microorganism dissemination to sensitive pinniped populations.
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Abstract
Integrons are versatile gene acquisition systems commonly found in bacterial genomes. They are ancient elements that are a hot spot for genomic complexity, generating phenotypic diversity and shaping adaptive responses. In recent times, they have had a major role in the acquisition, expression, and dissemination of antibiotic resistance genes. Assessing the ongoing threats posed by integrons requires an understanding of their origins and evolutionary history. This review examines the functions and activities of integrons before the antibiotic era. It shows how antibiotic use selected particular integrons from among the environmental pool of these elements, such that integrons carrying resistance genes are now present in the majority of Gram-negative pathogens. Finally, it examines the potential consequences of widespread pollution with the novel integrons that have been assembled via the agency of human antibiotic use and speculates on the potential uses of integrons as platforms for biotechnology.
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Genetic acquisition of NDM gene offers sustainability among clinical isolates of Pseudomonas aeruginosa in clinical settings. PLoS One 2015; 10:e0116611. [PMID: 25635921 PMCID: PMC4312061 DOI: 10.1371/journal.pone.0116611] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 12/11/2014] [Indexed: 11/19/2022] Open
Abstract
New Delhi metallo β-lactamases are one of the most significant emerging resistance determinants towards carbapenem drugs. Their persistence and adaptability often depends on their genetic environment and linkage. This study reports a unique and novel arrangement of blaNDM-1 gene within clinical isolates of Pseudomonas aeruginosa from a tertiary referral hospital in north India. Three NDM positive clonally unrelated clinical isolates of P. aeruginosa were recovered from hospital patients. Association of integron with blaNDM-1 and presence of gene cassettes were assessed by PCR. Genetic linkage of NDM gene with ISAba125 was determined and in negative cases linkage in upstream region was mapped by inverse PCR. In which only one isolate’s NDM gene was linked with ISAba125 for mobility, while other two reveals new genetic arrangement and found to be inserted within DNA directed RNA polymerase gene of the host genome detected by inverse PCR followed by sequencing analysis. In continuation significance of this novel linkage was further analyzed wherein promoter site detected by Softberry BPROM software and activity were assessed by cloning succeeding semi-quantitative RT-PCR indicating the higher expression level of NDM gene. This study concluded out that the unique genetic makeup of NDM gene with DNA-dependent-RNA-polymerase favours adaptability to the host in hospital environment against huge antibiotic pressure.
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Maurya AP, Choudhury D, Talukdar AD, Dhar (Chanda) A, Chakravarty A, Bhattacharjee A. A report on the presence of GES-5 extended spectrum beta-lactamase producing Pseudomonas aeruginosa associated with urinary tract infection from north-east India. Indian J Med Res 2014; 140:565-7. [PMID: 25488455 PMCID: PMC4277147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
| | - Debarati Choudhury
- Department of Life Science & Bioinformatics, Assam University, Silchar 788 011, India
| | - Anupam Das Talukdar
- Department of Life Science & Bioinformatics, Assam University, Silchar 788 011, India
| | - Anupam Dhar (Chanda)
- Department of Microbiology, Silchar Medical College & Hospital, Silchar 788 014, India
| | - Atanu Chakravarty
- Department of Microbiology, Silchar Medical College & Hospital, Silchar 788 014, India
| | - Amitabha Bhattacharjee
- Department of Microbiology, Assam University, Silchar 788 011, India,For correspondence:
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Culligan EP, Sleator RD, Marchesi JR, Hill C. Metagenomics and novel gene discovery: promise and potential for novel therapeutics. Virulence 2014; 5:399-412. [PMID: 24317337 PMCID: PMC3979868 DOI: 10.4161/viru.27208] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/21/2013] [Accepted: 11/14/2013] [Indexed: 02/06/2023] Open
Abstract
Metagenomics provides a means of assessing the total genetic pool of all the microbes in a particular environment, in a culture-independent manner. It has revealed unprecedented diversity in microbial community composition, which is further reflected in the encoded functional diversity of the genomes, a large proportion of which consists of novel genes. Herein, we review both sequence-based and functional metagenomic methods to uncover novel genes and outline some of the associated problems of each type of approach, as well as potential solutions. Furthermore, we discuss the potential for metagenomic biotherapeutic discovery, with a particular focus on the human gut microbiome and finally, we outline how the discovery of novel genes may be used to create bioengineered probiotics.
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Affiliation(s)
- Eamonn P Culligan
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- School of Microbiology; University College Cork; Cork, Ireland
| | - Roy D Sleator
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
| | - Julian R Marchesi
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- Cardiff School of Biosciences; Cardiff University; Cardiff, UK
- Department of Hepatology and Gastroenterology; Imperial College London; London, UK
| | - Colin Hill
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- School of Microbiology; University College Cork; Cork, Ireland
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Berglund B, Khan GA, Weisner SEB, Ehde PM, Fick J, Lindgren PE. Efficient removal of antibiotics in surface-flow constructed wetlands, with no observed impact on antibiotic resistance genes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 476-477:29-37. [PMID: 24448029 DOI: 10.1016/j.scitotenv.2013.12.128] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/20/2013] [Accepted: 12/30/2013] [Indexed: 06/03/2023]
Abstract
Recently, there have been growing concerns about pharmaceuticals including antibiotics as environmental contaminants. Antibiotics of concentrations commonly encountered in wastewater have been suggested to affect bacterial population dynamics and to promote dissemination of antibiotic resistance. Conventional wastewater treatment processes do not always adequately remove pharmaceuticals causing environmental dissemination of low levels of these compounds. Using constructed wetlands as an additional treatment step after sewage treatment plants have been proposed as a cheap alternative to increase reduction of wastewater contaminants, however this means that the natural microbial community of the wetlands becomes exposed to elevated levels of antibiotics. In this study, experimental surface-flow wetlands in Sweden were continuously exposed to antibiotics of concentrations commonly encountered in wastewater. The aim was to assess the antibiotic removal efficiency of constructed wetlands and to evaluate the impact of low levels of antibiotics on bacterial diversity, resistance development and expression in the wetland bacterial community. Antibiotic concentrations were measured using liquid chromatography-mass spectrometry and the effect on the bacterial diversity was assessed with 16S rRNA-based denaturing gradient gel electrophoresis. Real-time PCR was used to detect and quantify antibiotic resistance genes and integrons in the wetlands, during and after the exposure period. The results indicated that the antibiotic removal efficiency of constructed wetlands was comparable to conventional wastewater treatment schemes. Furthermore, short-term treatment of the constructed wetlands with environmentally relevant concentrations (i.e. 100-2000 ng×l(-1)) of antibiotics did not significantly affect resistance gene concentrations, suggesting that surface-flow constructed wetlands are well-suited for wastewater treatment purposes.
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Affiliation(s)
- Björn Berglund
- Linköping University, Division of Medical Microbiology, Department of Clinical and Experimental Medicine, SE-581 85 Linköping, Sweden.
| | | | - Stefan E B Weisner
- Wetland Research Centre, Halmstad University, P.O. Box 823, SE-301 18 Halmstad, Sweden
| | - Per Magnus Ehde
- Wetland Research Centre, Halmstad University, P.O. Box 823, SE-301 18 Halmstad, Sweden
| | - Jerker Fick
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Per-Eric Lindgren
- Linköping University, Division of Medical Microbiology, Department of Clinical and Experimental Medicine, SE-581 85 Linköping, Sweden; Department of Microbiology, Medical Services, County Hospital Ryhov, SE-551 85 Jönköping, Sweden
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Elsaied H, Stokes HW, Yoshioka H, Mitani Y, Maruyama A. Novel integrons and gene cassettes from a Cascadian submarine gas-hydrate-bearing core. FEMS Microbiol Ecol 2013; 87:343-56. [PMID: 24117886 DOI: 10.1111/1574-6941.12227] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 09/14/2013] [Accepted: 09/16/2013] [Indexed: 11/28/2022] Open
Abstract
To determine whether integrons are present in a submarine gas hydrate community, metagenomic DNA was extracted from a gas-hydrate-bearing core, 150 m below the seafloor, from the Cascadian Margin. Integrons and gene cassettes were recovered by PCR from metagenomic DNA and sequenced. Thirty-seven integron integrase phylotypes were identified. The phylotypes were diverse and included members with homology to integrases from Methylomonas methanica, Desulfuromonas acetoxidans, Thermodesulfatator indicus, and marine uncultured bacteria. The gene cassette composition, 153 gene cassettes, was dominated by two types of encoded putative proteins. The first of these was predicted oxidoreductases, such as iron/sulfur cluster-binding proteins. A second type was alkyl transferases. Some cassette proteins showed homologies with those from methane-related archaea. These observations suggest that integrons may assist in the adaptation of microbial communities in this environment.
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Affiliation(s)
- Hosam Elsaied
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, AIST, Tsukuba, Japan; Genetics and Biotechnology Research Group, National Institute of Oceanography, Cairo, Egypt
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Filip R, Chihu-Amparan L, Coman G, Velázquez ME, Silva J. Molecular Characterization of β-lactam Resistance ofSalmonellaIsolates from Pediatric Patients in Romania. J Chemother 2013; 16:337-42. [PMID: 15332707 DOI: 10.1179/joc.2004.16.4.337] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The molecular characterization of 16 clinical isolates of Salmonella enterica (14 serotype Typhimurium and 2 serotype Kingston) obtained between January and June 1999 from feces of children hospitalized in Iasi, Romania were genotypically compared by pulse field gel electrophoresis of XbaI restricted bacterial DNA. The majority of the clinical isolates (12/16) belonged to cluster A and (4/16) to unrelated strains, correlating to the OMP profile. Two major different patterns of beta-lactamases were identified: the first with pI of 5.4, 8.2 in 6/16 strains and the second with pI of 5.4 in 5/16. The blaTEM beta-lactamase was identified in 14/16 of the clinical isolates and the blaSHV-5 gene in one strain. We concluded that extended spectrum beta-lactamase (ESBL) with pIs of 8.2 was the most frequent enzyme produced by serotype Typhimurium isolates which were related.
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Affiliation(s)
- R Filip
- Department of Microbiology, Faculty of Medicine, University of Medicine and Pharmacy Gr.T. Popa Iasi, Romania
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Mishra S, Sen MR, Upadhyay S, Bhattacharjee A. Genetic linkage of blaNDM among nosocomial isolates of Acinetobacter baumannii from a tertiary referral hospital in northern India. Int J Antimicrob Agents 2013; 41:452-6. [DOI: 10.1016/j.ijantimicag.2013.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 12/29/2012] [Accepted: 01/03/2013] [Indexed: 11/30/2022]
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Wu YW, Doak TG, Ye Y. The gain and loss of chromosomal integron systems in the Treponema species. BMC Evol Biol 2013; 13:16. [PMID: 23339550 PMCID: PMC3607928 DOI: 10.1186/1471-2148-13-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 01/11/2013] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Integron systems are now recognized as important agents of bacterial evolution and are prevalent in most environments. One of the human pathogens known to harbor chromosomal integrons, the Treponema spirochetes are the only clade among spirochete species found to carry integrons. With the recent release of many new Treponema genomes, we were able to study the distribution of chromosomal integrons in this genus. RESULTS We find that the Treponema spirochetes implicated in human periodontal diseases and those isolated from cow and swine intestines contain chromosomal integrons, but not the Treponema species isolated from termite guts. By examining the species tree of selected spirochetes (based on 31 phylogenetic marker genes) and the phylogenetic tree of predicted integron integrases, and assisted by our analysis of predicted integron recombination sites, we found that all integron systems identified in Treponema spirochetes are likely to have evolved from a common ancestor--a horizontal gain into the clade. Subsequent to this event, the integron system was lost in the branch leading to the speciation of T. pallidum and T. phagedenis (the Treponema sps. implicated in sexually transmitted diseases). We also find that the lengths of the integron attC sites shortened through Treponema speciation, and that the integron gene cassettes of T. denticola are highly strain specific. CONCLUSIONS This is the first comprehensive study to characterize the chromosomal integron systems in Treponema species. By characterizing integron distribution and cassette contents in the Treponema sps., we link the integrons to the speciation of the various species, especially to the pathogens T. pallidum and T. phagedenis.
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Affiliation(s)
- Yu-Wei Wu
- School of Informatics and Computing, Indiana University, Bloomington, IN 47408, USA
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Sureshan V, Deshpande CN, Boucher Y, Koenig JE, Stokes HW, Harrop SJ, Curmi PMG, Mabbutt BC. Integron gene cassettes: a repository of novel protein folds with distinct interaction sites. PLoS One 2013; 8:e52934. [PMID: 23349695 PMCID: PMC3548836 DOI: 10.1371/journal.pone.0052934] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 11/26/2012] [Indexed: 11/19/2022] Open
Abstract
Mobile gene cassettes captured within integron arrays encompass a vast and diverse pool of genetic novelty. In most cases, functional annotation of gene cassettes directly recovered by cassette-PCR is obscured by their characteristically high sequence novelty. This inhibits identification of those specific functions or biological features that might constitute preferential factors for lateral gene transfer via the integron system. A structural genomics approach incorporating x-ray crystallography has been utilised on a selection of cassettes to investigate evolutionary relationships hidden at the sequence level. Gene cassettes were accessed from marine sediments (pristine and contaminated sites), as well as a range of Vibrio spp. We present six crystal structures, a remarkably high proportion of our survey of soluble proteins, which were found to possess novel folds. These entirely new structures are diverse, encompassing all-α, α+β and α/β fold classes, and many contain clear binding pocket features for small molecule substrates. The new structures emphasise the large repertoire of protein families encoded within the integron cassette metagenome and which remain to be characterised. Oligomeric association is a notable recurring property common to these new integron-derived proteins. In some cases, the protein–protein contact sites utilised in homomeric assembly could instead form suitable contact points for heterogeneous regulator/activator proteins or domains. Such functional features are ideal for a flexible molecular componentry needed to ensure responsive and adaptive bacterial functions.
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Affiliation(s)
- Visaahini Sureshan
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Chandrika N. Deshpande
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Yan Boucher
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Jeremy E. Koenig
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - H. W. Stokes
- ithree institute, University of Technology, Sydney, New South Wales, Australia
| | - Stephen J. Harrop
- School of Physics, University of New South Wales, New South Wales, Australia
| | - Paul M. G. Curmi
- School of Physics, University of New South Wales, New South Wales, Australia
- Centre for Applied Medical Research, St Vincent's Hospital, Sydney, New South Wales, Australia
| | - Bridget C. Mabbutt
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
- * E-mail:
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Tennstedt T, Szczepanowski R, Braun S, Pühler A, Schlüter A. Occurrence of integron-associated resistance gene cassettes located on antibiotic resistance plasmids isolated from a wastewater treatment plant. FEMS Microbiol Ecol 2012; 45:239-52. [PMID: 19719593 DOI: 10.1016/s0168-6496(03)00164-8] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The role of a municipal wastewater treatment plant as a reservoir for bacteria carrying antibiotic resistance plasmids was analysed. Altogether, ninety-seven different multiresistance plasmids were isolated and screened by PCR for the presence of class 1 integron-specific sequences. Twelve of these plasmids were identified to carry integrons. In addition, integron-specific sequences were found on plasmid-DNA preparations from bacteria residing in activated sludge and in the final effluents of the wastewater treatment plant. Sequencing and annotation of the integrons identified nineteen different gene cassette arrays, containing twenty-one different resistance gene cassettes. These cassettes carry genes encoding eight different aminoglycoside-modifying enzymes, seven dihydrofolate reductases, three beta-lactamases, two chloramphenicol resistance proteins and two small exporter proteins. Moreover, new gene cassettes and cassettes with unknown function were identified. Eleven gene cassette combinations are described for the first time. Six integron-associated gene cassette arrays are located on self-transmissible, putative broad-host-range plasmids belonging to the IncP group. Hybridisation analyses, using the integron-specific gene cassette arrays as templates and labelled plasmid-DNA preparations from bacteria of the final effluents as hybridisation probes, revealed that bacteria containing integron-specific sequences on plasmids are released into the environment.
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Affiliation(s)
- Thomas Tennstedt
- Fakultät für Biologie, Lehrstuhl für Genetik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
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Rodríguez-Lecompte JC, Yitbarek A, Brady J, Sharif S, Cavanagh MD, Crow G, Guenter W, House JD, Camelo-Jaimes G. The effect of microbial-nutrient interaction on the immune system of young chicks after early probiotic and organic acid administration1. J Anim Sci 2012; 90:2246-54. [DOI: 10.2527/jas.2011-4184] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - A. Yitbarek
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - J. Brady
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - S. Sharif
- Department of Pathobiology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - M. D. Cavanagh
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - G. Crow
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - W. Guenter
- Department of Animal Science, University of Manitoba, Winnipeg R3T 2N2, Canada
| | - J. D. House
- Department of Human Nutritional Science, University of Manitoba, Winnipeg R3T 2N2, Canada
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Nardelli M, Scalzo PM, Ramírez MS, Quiroga MP, Cassini MH, Centrón D. Class 1 integrons in environments with different degrees of urbanization. PLoS One 2012; 7:e39223. [PMID: 22761743 PMCID: PMC3382206 DOI: 10.1371/journal.pone.0039223] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 05/17/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Class 1 integrons are one of the most successful elements in the acquisition, expression and spread of antimicrobial resistance genes (ARG) among clinical isolates. Little is known about the gene flow of the components of the genetic platforms of class 1 integrons within and between bacterial communities. Thus it is important to better understand the interactions among "environmental" intI1, its genetic platforms and its distribution with human activities. METHODOLOGY/PRINCIPAL FINDINGS An evaluation of two types of genetic determinants, ARG (sul1 and qacE1/qacEΔ1 genes) and lateral genetic elements (LGE) (intI1, ISCR1 and tniC genes) in a model of a culture-based method without antibiotic selection was conducted in a gradient of anthropogenic disturbances in a Patagonian island recognized as being one of the last regions containing wild areas. The intI1, ISCR1 genes and intI1 pseudogenes that were found widespread throughout natural communities were not associated with urbanization (p>0.05). Each ARG that is embedded in the most common genetic platform of clinical class 1 integrons, showed different ecological and molecular behaviours in environmental samples. While the sul1 gene frequency was associated with urbanization, the qacE1/qacEΔ1 gene showed an adaptive role to several habitats. CONCLUSIONS/SIGNIFICANCE The high frequency of intI1 pseudogenes suggests that, although intI1 has a deleterious impact within several genomes, it can easily be disseminated among natural bacterial communities. The widespread occurrence of ISCR1 and intI1 throughout Patagonian sites with different degree of urbanization, and within different taxa, could be one of the causes of the increasing frequency of multidrug-resistant isolates that have characterized Argentina for decades. The flow of ARG and LGE between natural and clinical communities cannot be explained with a single general process but is a direct consequence of the interaction of multiple factors operating at molecular, ecological, phylogenetic and historical levels.
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Affiliation(s)
- Maximiliano Nardelli
- Laboratorio de Investigaciones de los Mecanismos de Resistencia a Antibióticos, Facultad de Medicina, Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Paula Marina Scalzo
- Laboratorio de Investigaciones de los Mecanismos de Resistencia a Antibióticos, Facultad de Medicina, Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - María Soledad Ramírez
- Laboratorio de Investigaciones de los Mecanismos de Resistencia a Antibióticos, Facultad de Medicina, Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - María Paula Quiroga
- Laboratorio de Investigaciones de los Mecanismos de Resistencia a Antibióticos, Facultad de Medicina, Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
| | - Marcelo Hernán Cassini
- Grupo GEMA, Departamento de Ciencias Básicas, Universidad Nacional de Luján, Luján, Buenos Aires, Argentina
- Laboratorio de Biología del Comportamiento, IBYME, Ciudad Autónoma de Buenos Aires, Argentina
| | - Daniela Centrón
- Laboratorio de Investigaciones de los Mecanismos de Resistencia a Antibióticos, Facultad de Medicina, Instituto de Microbiología y Parasitología Médica (IMPaM, UBA-CONICET), Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
- * E-mail:
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Boyapati VK, Huang W, Spedale J, Aboul-ela F. Basis for ligand discrimination between ON and OFF state riboswitch conformations: the case of the SAM-I riboswitch. RNA (NEW YORK, N.Y.) 2012; 18:1230-1243. [PMID: 22543867 PMCID: PMC3358645 DOI: 10.1261/rna.032177.111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 03/17/2012] [Indexed: 05/31/2023]
Abstract
Riboswitches are RNA elements that bind to effector ligands and control gene expression. Most consist of two domains. S-Adenosyl Methionine (SAM) binds the aptamer domain of the SAM-I riboswitch and induces conformational changes in the expression domain to form an intrinsic terminator (transcription OFF state). Without SAM the riboswitch forms the transcription ON state, allowing read-through transcription. The mechanistic link between the SAM/aptamer recognition event and subsequent secondary structure rearrangement by the riboswitch is unclear. We probed for those structural features of the Bacillus subtilis yitJ SAM-I riboswitch responsible for discrimination between the ON and OFF states by SAM. We designed SAM-I riboswitch RNA segments forming "hybrid" structures of the ON and OFF states. The choice of segment constrains the formation of a partial P1 helix, characteristic of the OFF state, together with a partial antiterminator (AT) helix, characteristic of the ON state. For most choices of P1 vs. AT helix lengths, SAM binds with micromolar affinity according to equilibrium dialysis. Mutational analysis and in-line probing confirm that the mode of SAM binding by hybrid structures is similar to that of the aptamer. Altogether, binding measurements and in-line probing are consistent with the hypothesis that when SAM is present, stacking interactions with the AT helix stabilize a partially formed P1 helix in the hybrids. Molecular modeling indicates that continuous stacking between the P1 and the AT helices is plausible with SAM bound. Our findings raise the possibility that conformational intermediates may play a role in ligand-induced aptamer folding.
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Affiliation(s)
- Vamsi Krishna Boyapati
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70802, USA
| | - Wei Huang
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70802, USA
| | - Jessica Spedale
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70802, USA
| | - Fareed Aboul-ela
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70802, USA
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45
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Oral spirochetes implicated in dental diseases are widespread in normal human subjects and carry extremely diverse integron gene cassettes. Appl Environ Microbiol 2012; 78:5288-96. [PMID: 22635997 DOI: 10.1128/aem.00564-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The NIH Human Microbiome Project (HMP) has produced several hundred metagenomic data sets, allowing studies of the many functional elements in human-associated microbial communities. Here, we survey the distribution of oral spirochetes implicated in dental diseases in normal human individuals, using recombination sites associated with the chromosomal integron in Treponema genomes, taking advantage of the multiple copies of the integron recombination sites (repeats) in the genomes, and using a targeted assembly approach that we have developed. We find that integron-containing Treponema species are present in ∼80% of the normal human subjects included in the HMP. Further, we are able to de novo assemble the integron gene cassettes using our constrained assembly approach, which employs a unique application of the de Bruijn graph assembly information; most of these cassette genes were not assembled in whole-metagenome assemblies and could not be identified by mapping sequencing reads onto the known reference Treponema genomes due to the dynamic nature of integron gene cassettes. Our study significantly enriches the gene pool known to be carried by Treponema chromosomal integrons, totaling 826 (598 97% nonredundant) genes. We characterize the functions of these gene cassettes: many of these genes have unknown functions. The integron gene cassette arrays found in the human microbiome are extraordinarily dynamic, with different microbial communities sharing only a small number of common genes.
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46
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Diversity of integron- and culture-associated antibiotic resistance genes in freshwater floc. Appl Environ Microbiol 2012; 78:4367-72. [PMID: 22467502 DOI: 10.1128/aem.00405-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clinically important antibiotic resistance genes were detected in culturable bacteria and class 1 integron gene cassettes recovered from suspended floc, a significant aquatic repository for microorganisms and trace elements, across freshwater systems variably impacted by anthropogenic activities. Antibiotic resistance gene cassettes in floc total community DNA differed appreciably in number and type from genes detected in bacteria cultured from floc. The number of floc antibiotic resistance gene cassette types detected across sites was positively correlated with total (the sum of Ag, As, Cu, and Pb) trace element concentrations in aqueous solution and in a component of floc readily accessible to bacteria. In particular, concentrations of Cu and Pb in the floc component were positively correlated with floc resistance gene cassette diversity. Collectively, these results identify suspended floc as an important reservoir, distinct from bulk water and bed sediment, for antibiotic resistance in aquatic environments ranging from heavily impacted urban sites to remote areas of nature reserves and indicate that trace elements, particularly Cu and Pb, are geochemical markers of resistance diversity in this environmental reservoir. The increase in contamination of global water supplies suggests that aquatic environments will become an even more important reservoir of clinically important antibiotic resistance in the future.
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47
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Martínez-Rosales C, Fullana N, Musto H, Castro-Sowinski S. Antarctic DNA moving forward: genomic plasticity and biotechnological potential. FEMS Microbiol Lett 2012; 331:1-9. [PMID: 22360528 DOI: 10.1111/j.1574-6968.2012.02531.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/09/2012] [Accepted: 02/18/2012] [Indexed: 02/06/2023] Open
Abstract
Antarctica is the coldest, driest, and windiest continent, where only cold-adapted organisms survive. It has been frequently cited as a pristine place, but it has a highly diverse microbial community that is continually seeded by nonindigenous microorganisms. In addition to the intromission of 'alien' microorganisms, global warming strongly affects microbial Antarctic communities, changing the genes (qualitatively and quantitatively) potentially available for horizontal gene transfer. Several mobile genetic elements have been described in Antarctic bacteria (including plasmids, transposons, integrons, and genomic islands), and the data support that they are actively involved in bacterial evolution in the Antarctic environment. In addition, this environment is a genomic source for the identification of novel molecules, and many investigators have used culture-dependent and culture-independent approaches to identify cold-adapted proteins. Some of them are described in this review. We also describe studies for the design of new recombinant technologies for the production of 'difficult' proteins.
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Elsaied H, Stokes HW, Kitamura K, Kurusu Y, Kamagata Y, Maruyama A. Marine integrons containing novel integrase genes, attachment sites, attI, and associated gene cassettes in polluted sediments from Suez and Tokyo Bays. THE ISME JOURNAL 2011; 5:1162-77. [PMID: 21248857 PMCID: PMC3146285 DOI: 10.1038/ismej.2010.208] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 10/14/2010] [Accepted: 12/14/2010] [Indexed: 11/21/2022]
Abstract
In order to understand the structure and biological significance of integrons and associated gene cassettes in marine polluted sediments, metagenomic DNAs were extracted from sites at Suez and Tokyo Bays. PCR amplicons containing new integrase genes, intI, linked with novel gene cassettes, were recovered and had sizes from 1.8 to 2.5 kb. This approach uncovered, for the first time, the structure and diversity of both marine integron attachment site, attI, and the first gene cassette, the most efficiently expressed integron-associated gene cassette. The recovered 13 and 20 intI phylotypes, from Suez and Tokyo Bay samples, respectively, showed a highly divergence, suggesting a difference in integron composition between the sampling sites. Some intI phylotypes showed similarity with that from Geobacter metallireducens, belonging to Deltaproteobacteria, the dominant class in both sampling sites, as determined by 16S rRNA gene analysis. Thirty distinct families of putative attI site, as determined by the presence of an attI-like simple site, were recovered. A total of 146 and 68 gene cassettes represented Suez and Tokyo Bay unsaturated cassette pools, respectively. Gene cassettes, including a first cassette, from both sampling sites encoded two novel families of glyoxalase/bleomycin antibiotic-resistance protein. Gene cassettes from Suez Bay encoded proteins similar to haloacid dehalogenases, protein disulfide isomerases and death-on-curing and plasmid maintenance system killer proteins. First gene cassettes from Tokyo Bay encoded a xenobiotic-degrading protein, cardiolipin synthetase, esterase and WD40-like β propeller protein. Many of the first gene cassettes encoded proteins with no ascribable function but some of them were duplicated and possessed signal functional sites, suggesting efficient adaptive functions to their bacterial sources. Thus, each sampling site had a specific profile of integrons and cassette types consistent with the hypothesis that the environment shapes the genome.
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Affiliation(s)
- Hosam Elsaied
- Microbial and Genetic Resources Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi Tsukuba, Ibaraki, Japan
- Department of Genetics, National Institute of Oceanography, Cairo, Egypt
| | - Hatch W Stokes
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, New South Wales, Australia
| | - Keiko Kitamura
- Microbial and Genetic Resources Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi Tsukuba, Ibaraki, Japan
| | - Yasurou Kurusu
- Department of Molecular Microbiology, College of Agriculture, Ibaraki University, Ami, Ibaraki, Japan
| | - Yoichi Kamagata
- Microbial and Genetic Resources Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi Tsukuba, Ibaraki, Japan
| | - Akihiko Maruyama
- Microbial and Genetic Resources Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi Tsukuba, Ibaraki, Japan
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Deshpande CN, Harrop SJ, Boucher Y, Hassan KA, Leo RD, Xu X, Cui H, Savchenko A, Chang C, Labbate M, Paulsen IT, Stokes HW, Curmi PMG, Mabbutt BC. Crystal structure of an integron gene cassette-associated protein from Vibrio cholerae identifies a cationic drug-binding module. PLoS One 2011; 6:e16934. [PMID: 21390267 PMCID: PMC3048380 DOI: 10.1371/journal.pone.0016934] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 01/05/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The direct isolation of integron gene cassettes from cultivated and environmental microbial sources allows an assessment of the impact of the integron/gene cassette system on the emergence of new phenotypes, such as drug resistance or virulence. A structural approach is being exploited to investigate the modularity and function of novel integron gene cassettes. METHODOLOGY/PRINCIPAL FINDINGS We report the 1.8 Å crystal structure of Cass2, an integron-associated protein derived from an environmental V. cholerae. The structure defines a monomeric beta-barrel protein with a fold related to the effector-binding portion of AraC/XylS transcription activators. The closest homologs of Cass2 are multi-drug binding proteins, such as BmrR. Consistent with this, a binding pocket made up of hydrophobic residues and a single glutamate side chain is evident in Cass2, occupied in the crystal form by polyethylene glycol. Fluorescence assays demonstrate that Cass2 is capable of binding cationic drug compounds with submicromolar affinity. The Cass2 module possesses a protein interaction surface proximal to its drug-binding cavity with features homologous to those seen in multi-domain transcriptional regulators. CONCLUSIONS/SIGNIFICANCE Genetic analysis identifies Cass2 to be representative of a larger family of independent effector-binding proteins associated with lateral gene transfer within Vibrio and closely-related species. We propose that the Cass2 family not only has capacity to form functional transcription regulator complexes, but represents possible evolutionary precursors to multi-domain regulators associated with cationic drug compounds.
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Affiliation(s)
- Chandrika N. Deshpande
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Stephen J. Harrop
- School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- St Vincent's Centre for Applied Medical Research, Sydney, New South Wales, Australia
| | - Yan Boucher
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Karl A. Hassan
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Rosa Di Leo
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
| | - Xiaohui Xu
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
| | - Hong Cui
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
| | - Alexei Savchenko
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
| | - Changsoo Chang
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
| | - Maurizio Labbate
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, New South Wales, Australia
| | - Ian T. Paulsen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - H. W. Stokes
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, New South Wales, Australia
| | - Paul M. G. Curmi
- School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- St Vincent's Centre for Applied Medical Research, Sydney, New South Wales, Australia
| | - Bridget C. Mabbutt
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
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Abstract
Pseudomonas aeruginosa strains exhibit significant variability in pathogenicity and ecological flexibility. Such interstrain differences reflect the dynamic nature of the P. aeruginosa genome, which is composed of a relatively invariable "core genome" and a highly variable "accessory genome." Here we review the major classes of genetic elements comprising the P. aeruginosa accessory genome and highlight emerging themes in the acquisition and functional importance of these elements. Although the precise phenotypes endowed by the majority of the P. aeruginosa accessory genome have yet to be determined, rapid progress is being made, and a clearer understanding of the role of the P. aeruginosa accessory genome in ecology and infection is emerging.
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