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Piscon B, Pia Esposito E, Fichtman B, Samburski G, Efremushkin L, Amselem S, Harel A, Rahav G, Zarrilli R, Gal-Mor O. The Effect of Outer Space and Other Environmental Cues on Bacterial Conjugation. Microbiol Spectr 2023; 11:e0368822. [PMID: 36995224 PMCID: PMC10269834 DOI: 10.1128/spectrum.03688-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 03/11/2023] [Indexed: 03/31/2023] Open
Abstract
Bacterial conjugation is one of the most abundant horizontal gene transfer (HGT) mechanisms, playing a fundamental role in prokaryote evolution. A better understanding of bacterial conjugation and its cross talk with the environment is needed for a more complete understanding of HGT mechanisms and to fight the dissemination of malicious genes between bacteria. Here, we studied the effect of outer space, microgravity, and additional key environmental cues on transfer (tra) gene expression and conjugation efficiency, using the under studied broad-host range plasmid pN3, as a model. High resolution scanning electron microscopy revealed the morphology of the pN3 conjugative pili and mating pair formation during conjugation. Using a nanosatellite carrying a miniaturized lab, we studied pN3 conjugation in outer space, and used qRT-PCR, Western blotting and mating assays to determine the effect of ground physicochemical parameters on tra gene expression and conjugation. We showed for the first time that bacterial conjugation can occur in outer space and on the ground, under microgravity-simulated conditions. Furthermore, we demonstrated that microgravity, liquid media, elevated temperature, nutrient depletion, high osmolarity and low oxygen significantly reduce pN3 conjugation. Interestingly, under some of these conditions we observed an inverse correlation between tra gene transcription and conjugation frequency and found that induction of at least traK and traL can negatively affect pN3 conjugation frequency in a dose-dependent manner. Collectively, these results uncover pN3 regulation by various environmental cues and highlight the diversity of conjugation systems and the different ways in which they may be regulated in response to abiotic signals. IMPORTANCE Bacterial conjugation is a highly ubiquitous and promiscuous process, by which a donor bacterium transfers a large portion of genetic material to a recipient cell. This mechanism of horizontal gene transfer plays an important role in bacterial evolution and in the ability of bacteria to acquire resistance to antimicrobial drugs and disinfectants. Bacterial conjugation is a complex and energy-consuming process, that is tightly regulated and largely affected by various environmental signals sensed by the bacterial cell. Comprehensive knowledge about bacterial conjugation and the ways it is affected by environmental cues is required to better understand bacterial ecology and evolution and to find new effective ways to counteract the threating dissemination of antibiotic resistance genes between bacterial populations. Moreover, characterizing this process under stress or suboptimal growth conditions such as elevated temperatures, high salinity or in the outer space, may provide insights relevant to future habitat environmental conditions.
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Affiliation(s)
- Bar Piscon
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eliana Pia Esposito
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Boris Fichtman
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Guy Samburski
- SpacePharma R&D Israel LTD., Herzliya Pituach, Israel & SpacePharma SA, Courgenay, Switzerland
| | - Lihi Efremushkin
- SpacePharma R&D Israel LTD., Herzliya Pituach, Israel & SpacePharma SA, Courgenay, Switzerland
| | - Shimon Amselem
- SpacePharma R&D Israel LTD., Herzliya Pituach, Israel & SpacePharma SA, Courgenay, Switzerland
| | - Amnon Harel
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Galia Rahav
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Ohad Gal-Mor
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Sun R, Yu P, Zuo P, Alvarez PJ. Bacterial Concentrations and Water Turbulence Influence the Importance of Conjugation Versus Phage-Mediated Antibiotic Resistance Gene Transfer in Suspended Growth Systems. ACS ENVIRONMENTAL AU 2022; 2:156-165. [PMID: 37101581 PMCID: PMC10114721 DOI: 10.1021/acsenvironau.1c00027] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Despite the abundance of phage-borne antibiotic resistance genes (ARGs) in the environment, the frequency of ARG propagation via phage-mediated transduction (relative to via conjugation) is poorly understood. We investigated the influence of bacterial concentration and water turbulence level [quantified as Reynold's number (Re)] in suspended growth systems on the frequency of ARG transfer by two mechanisms: delivery by a lysogenic phage (phage λ carrying gentamycin-resistance gene, genR) and conjugation mediated by the self-transmissible plasmid RP4. Using Escherichia coli (E. coli) as the recipient, phage delivery had a comparable frequency (1.2 ± 0.9 × 10-6) to that of conjugation (1.1 ± 0.9 × 10-6) in suspensions with low cell concentration (104 CFU/mL) and moderate turbulence (Re = 5 × 104). Turbulence affected cell (or phage)-to-cell contact rates and detachment (due to shear force), and thus, it affected the relative importance of conjugation versus phage delivery. At 107 CFU/mL, no significant difference was observed between the frequencies of ARG transfer by the two mechanisms under quiescent water conditions (2.8 ± 0.3 × 10-5 for conjugation vs 2.2 ± 0.5 × 10-5 for phage delivery, p = 0.19) or when Re reached 5 × 105 (3.4 ± 1.5 × 10-5 for conjugation vs 2.9 ± 1.0 × 10-5 for phage delivery, p = 0.52). Transcriptomic analysis of genes related to conjugation and phage delivery and simulation of cell (or phage)-to-cell collisions at different Re values corroborate that the importance of phage delivery relative to conjugation increases under either quiescent or turbulent conditions. This finding challenges the prevailing view that conjugation is the dominant ARG transfer mechanism and underscores the need to consider and mitigate potential ARG dissemination via transduction.
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Affiliation(s)
- Ruonan Sun
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Pingfeng Yu
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Pengxiao Zuo
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Pedro J.J. Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
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Abstract
Horizontal transfer of bacterial plasmids generates genetic variability and contributes to the dissemination of the genes that enable bacterial cells to develop antimicrobial resistance (AMR). Several aspects of the conjugative process have long been known, namely, those related to the proteins that participate in the establishment of cell-to-cell contact and to the enzymatic processes associated with the processing of plasmid DNA and its transfer to the recipient cell. In this work, we describe the roles of newly identified proteins that influence the conjugation of several plasmids. Genes encoding high-molecular-weight bacterial proteins that contain one or several immunoglobulin-like domains (Big) are located in the transfer regions of several plasmids that usually harbor AMR determinants. These Big proteins are exported to the external medium and target two extracellular organelles: the flagella and conjugative pili. The plasmid gene-encoded Big proteins facilitate conjugation by reducing cell motility and facilitating cell-to-cell contact by binding both to the flagella and to the conjugative pilus. They use the same export machinery as that used by the conjugative pilus components. In the examples characterized in this paper, these proteins influence conjugation at environmental temperatures (i.e., 25°C). This suggests that they may play relevant roles in the dissemination of plasmids in natural environments. Taking into account that they interact with outer surface organelles, they could be targeted to control the dissemination of different bacterial plasmids carrying AMR determinants. IMPORTANCE Transmission of a plasmid from one bacterial cell to another, in several instances, underlies the dissemination of antimicrobial resistance (AMR) genes. The process requires well-characterized enzymatic machinery that facilitates cell-to-cell contact and the transfer of the plasmid. Our paper identifies novel plasmid gene-encoded high-molecular-weight proteins that contain an immunoglobulin-like domain and are required for plasmid transmission. They are encoded by genes on different groups of plasmids. These proteins are exported outside the cell. They bind to extracellular cell appendages such as the flagella and conjugative pili. Expression of these proteins reduces cell motility and increases the ability of the bacterial cells to transfer the plasmid. These proteins could be targeted with specific antibodies to combat infections caused by AMR microorganisms that harbor these plasmids.
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4
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Harmer CJ. HI1 and I1 Resistance Plasmids from Salmonella enterica Serovar Typhimurium Strain SRC27 Are Epidemic. Microb Drug Resist 2021; 27:1495-1504. [PMID: 34242087 DOI: 10.1089/mdr.2020.0579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Conjugative plasmids are a major contributor to the global spread of antibiotic resistance determinants, but the tracking of their evolutionary history is often neglected. Salmonella enterica serovar Typhimurium (S. Typhimurium) strain SRC27 was isolated from an equine infection in Australia in 1999. SRC27 was known to carry conjugative HI1 and I1 resistance plasmids. In this study, SRC27 was sequenced to determine the relationship between these HI1 and I1 resistance plasmids it was known to carry and HI1 and I1 resistance plasmids circulating worldwide. The resistance genes in the HI1 plasmid, pSRC27-H, are all located in a single complex 34.7 kb resistance region. The backbone sequence and location of the pSRC27-H resistance island were used to identify the most closely related HI1 plasmids among the >90 that have been sequenced since 2011. This defined a sublineage of 20 type 2 HI1 plasmids that have been circulating in Europe, Asia, North America, and Australia since at least 1993. The overall resistance gene content of these HI1 plasmids differs, indicating extensive evolution in situ through the acquisition of additional transposons and deletion or replacement of ancestral regions. The I1 plasmid contains a complete copy of Tn5393a, containing the strAB genes that confer resistance to streptomycin. The precise location of Tn5393a in the backbone also defined a globally disseminated sublineage of I1 plasmids, many of which have also acquired additional resistance determinants. The sequence revealed that SRC27 also carried two additional plasmids, the pSLT-type FIB(S):FII(S) virulence plasmid and a small cryptic theta-replicating Col156 plasmid.
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Affiliation(s)
- Christopher J Harmer
- School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
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Gibert M, Paytubi S, Madrid C, Balsalobre C. Temperature Dependent Control of the R27 Conjugative Plasmid Genes. Front Mol Biosci 2020; 7:124. [PMID: 32754612 PMCID: PMC7366339 DOI: 10.3389/fmolb.2020.00124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/02/2020] [Indexed: 11/25/2022] Open
Abstract
Conjugation of R27 plasmid is thermoregulated, being promoted at 25°C and repressed at 37°C. Previous studies identified plasmid-encoded regulators, HtdA, TrhR and TrhY, that control expression of conjugation-related genes (tra). Moreover, the nucleoid-associated protein H-NS represses conjugation at non-permissive temperature. A transcriptomic approach has been used to characterize the effect of temperature on the expression of the 205 R27 genes. Many of the 35 tra genes, directly involved in plasmid-conjugation, were upregulated at 25°C. However, the majority of the non-tra R27 genes—many of them with unknown function—were more actively expressed at 37°C. The role of HtdA, a regulator that causes repression of the R27 conjugation by counteracting TrhR/TrhY mediated activation of tra genes, has been investigated. Most of the R27 genes are severely derepressed at 25°C in an htdA mutant, suggesting that HtdA is involved also in the repression of R27 genes other than the tra genes. Interestingly, the effect of htdA mutation was abolished at non-permissive temperature, indicating that the HtdA-TrhR/TrhY regulatory circuit mediates the environmental regulation of R27 gene expression. The role of H-NS in the proposed model is discussed.
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Affiliation(s)
- Marta Gibert
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Sonia Paytubi
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Cristina Madrid
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Carlos Balsalobre
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
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Cuevas-Ferrando E, Guirado P, Miró E, Iglesias-Torrens Y, Navarro F, Alioto TS, Gómez-Garrido J, Madrid C, Balsalobre C. Tetracycline resistance transmission in Campylobacter is promoted at temperatures resembling the avian reservoir. Vet Microbiol 2020; 244:108652. [PMID: 32402330 DOI: 10.1016/j.vetmic.2020.108652] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 11/26/2022]
Abstract
Campylobacter is the causal agent of campylobacteriosis in humans, a self-limiting gastroenteritis. Campylobacteriosis is a zoonosis, commonly transmitted from contaminated chicken meat by either direct consumption or cross contamination during food manipulation. Presence of plasmids encoding for resistance to antibiotics such as tetracycline is common among Campylobacter isolates. In this report, we studied the effect of the temperature in the conjugation frequency of several tet(O) carrying plasmids, providing tetracycline resistance to the recipient cells. The conjugation frequency from donor cells carrying three previously characterized plasmids (pCjA13, pCjA9 and pTet) and from two clinical isolates was determined. Two temperatures, 37 and 42 °C, mimicking the conditions encountered by C. jejuni in the human and broiler chicken gastrointestinal tracts, respectively, were assessed. Our results clearly indicate that the conjugation process is promoted at high temperature. Accordingly, the transcriptional expression of some putative conjugative apparatus genes is thermoregulated, being induced at 42 °C. The two plasmids present in the clinical isolates were sequenced and assembled. Both plasmids are highly related among them and to the pTet plasmid. The high identity of the genes putatively involved in the conjugation process among the plasmids is in agreement with the similar behavior regarding the temperature dependency of the conjugative process. This report suggest that conjugation of plasmids carrying antibiotic resistance genes occurs preferentially at temperatures that resemble the gastrointestinal tract of birds, the main reservoir of C. jejuni.
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Affiliation(s)
- E Cuevas-Ferrando
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Av. Diagonal, 643, 08028, Barcelona Spain
| | - P Guirado
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Av. Diagonal, 643, 08028, Barcelona Spain
| | - E Miró
- Hospital de la Santa Creu i Sant Pau and Institut d'Investigació Biomèdica Sant Pau (IIB Sant Pau), Barcelona, Spain
| | - Y Iglesias-Torrens
- Hospital de la Santa Creu i Sant Pau and Institut d'Investigació Biomèdica Sant Pau (IIB Sant Pau), Barcelona, Spain; Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - F Navarro
- Hospital de la Santa Creu i Sant Pau and Institut d'Investigació Biomèdica Sant Pau (IIB Sant Pau), Barcelona, Spain; Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - T S Alioto
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - J Gómez-Garrido
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, 08028 Barcelona, Spain
| | - C Madrid
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Av. Diagonal, 643, 08028, Barcelona Spain.
| | - C Balsalobre
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Av. Diagonal, 643, 08028, Barcelona Spain.
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7
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Luque A, Paytubi S, Sánchez-Montejo J, Gibert M, Balsalobre C, Madrid C. Crosstalk between bacterial conjugation and motility is mediated by plasmid-borne regulators. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:708-717. [PMID: 31309702 DOI: 10.1111/1758-2229.12784] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
Plasmid conjugation is a major horizontal gene transfer mechanism. The acquisition of a plasmid may cause a perturbation of the cell functions in addition to provide advantageous properties for the recipient cell, such as the gaining of antibiotic resistances. The interplay between plasmid and chromosomal functions has been studied using the IncHI1 plasmid R27. Plasmids of the incompatibility group HI1, isolated from several Gram-negative pathogens, are associated with the spread of multidrug resistance. Their conjugation is tightly regulated by temperature, being repressed at temperatures within the host (37°C). In this report, we described that at permissive temperature, when conjugation of plasmid R27 is prompted, a reduction in the motility of the cells is observed. This reduction is mediated by the plasmid-encoded regulators TrhR/TrhY, which together with HtdA form a plasmid-borne regulatory circuit controlling R27 conjugation. TrhR/TrhY, required to induce R27 conjugation, is responsible for the downregulation of the flagella synthesis and the consequent decrease in motility. TrhR/TrhY repress, direct or indirectly, the expression of the specific flagellar sigma subunit FliA and, consequently, the expression of all genes located bellow in the flagellar expression cascade.
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Affiliation(s)
- Ainara Luque
- Secció de Microbiologia, Virologia i Biotecnologia. Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Sonia Paytubi
- Secció de Microbiologia, Virologia i Biotecnologia. Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Javier Sánchez-Montejo
- Secció de Microbiologia, Virologia i Biotecnologia. Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Marta Gibert
- Secció de Microbiologia, Virologia i Biotecnologia. Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Carlos Balsalobre
- Secció de Microbiologia, Virologia i Biotecnologia. Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Cristina Madrid
- Secció de Microbiologia, Virologia i Biotecnologia. Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
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8
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Hüttener M, Prieto A, Aznar S, Bernabeu M, Glaría E, Valledor AF, Paytubi S, Merino S, Tomás J, Juárez A. Expression of a novel class of bacterial Ig-like proteins is required for IncHI plasmid conjugation. PLoS Genet 2019; 15:e1008399. [PMID: 31527905 PMCID: PMC6764697 DOI: 10.1371/journal.pgen.1008399] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 09/27/2019] [Accepted: 09/04/2019] [Indexed: 01/10/2023] Open
Abstract
Antimicrobial resistance (AMR) is currently one of the most important challenges to the treatment of bacterial infections. A critical issue to combat AMR is to restrict its spread. In several instances, bacterial plasmids are involved in the global spread of AMR. Plasmids belonging to the incompatibility group (Inc)HI are widespread in Enterobacteriaceae and most of them express multiple antibiotic resistance determinants. They play a relevant role in the recent spread of colistin resistance. We present in this report novel findings regarding IncHI plasmid conjugation. Conjugative transfer in liquid medium of an IncHI plasmid requires expression of a plasmid-encoded, large-molecular-mass protein that contains an Ig-like domain. The protein, termed RSP, is encoded by a gene (ORF R0009) that maps in the Tra2 region of the IncHI1 R27 plasmid. The RSP protein is exported outside the cell by using the plasmid-encoded type IV secretion system that is also used for its transmission to new cells. Expression of the protein reduces cell motility and enables plasmid conjugation. Flagella are one of the cellular targets of the RSP protein. The RSP protein is required for a high rate of plasmid transfer in both flagellated and nonflagellated Salmonella cells. This effect suggests that RSP interacts with other cellular structures as well as with flagella. These unidentified interactions must facilitate mating pair formation and, hence, facilitate IncHI plasmid conjugation. Due to its location on the outer surfaces of the bacterial cell, targeting the RSP protein could be a means of controlling IncHI plasmid conjugation in natural environments or of combatting infections caused by AMR enterobacteria that harbor IncHI plasmids. Dissemination of antimicrobial resistance (AMR) among different bacterial populations occurs due to mainly the presence of plasmids that encode AMR determinants. IncHI plasmids are one of the groups of bacterial plasmids that confer AMR to several enterobacteria. Recently, resistance to one of the last-resort antibiotics (colistin) for some multidrug-resistant infections has spread very rapidly. IncHI plasmids represent 20% of all plasmids transmitting colistin resistance worldwide and 40% in Europe. When analyzing the interactions of the IncHI1 plasmid R27 with Salmonella, we identified a large-molecular-mass protein that is encoded by this plasmid and is exported to the external medium. The R27 plasmid gene coding for that protein (R0009) is widespread among IncHI plasmids. In this report, we characterize the protein, termed RSP. The presented data show that RSP plays a relevant role in IncHI plasmid conjugation and suggest that the protein is retained on the outer surface of the bacterial cells and facilitates cell-to-cell contact before plasmid DNA transfer. Considering that IncHI plasmids significantly contribute to AMR dissemination within enterobacteria, the findings reported in this paper suggest that the identified protein can be a target to control both IncHI-mediated AMR dissemination and infections caused by AMR enterobacteria that harbor these plasmids.
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Affiliation(s)
- Mário Hüttener
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Alejandro Prieto
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Sonia Aznar
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Manuel Bernabeu
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Estibaliz Glaría
- Department of Cell Biology, Physiology and Immunology, University of Barcelona, Barcelona, Spain
| | - Annabel F. Valledor
- Department of Cell Biology, Physiology and Immunology, University of Barcelona, Barcelona, Spain
| | - Sonia Paytubi
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Susana Merino
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Joan Tomás
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - Antonio Juárez
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, Barcelona, Spain
- * E-mail:
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9
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Rozwandowicz M, Brouwer MSM, Fischer J, Wagenaar JA, Gonzalez-Zorn B, Guerra B, Mevius DJ, Hordijk J. Plasmids carrying antimicrobial resistance genes in Enterobacteriaceae. J Antimicrob Chemother 2019; 73:1121-1137. [PMID: 29370371 DOI: 10.1093/jac/dkx488] [Citation(s) in RCA: 507] [Impact Index Per Article: 101.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bacterial antimicrobial resistance (AMR) is constantly evolving and horizontal gene transfer through plasmids plays a major role. The identification of plasmid characteristics and their association with different bacterial hosts provides crucial knowledge that is essential to understand the contribution of plasmids to the transmission of AMR determinants. Molecular identification of plasmid and strain genotypes elicits a distinction between spread of AMR genes by plasmids and dissemination of these genes by spread of bacterial clones. For this reason several methods are used to type the plasmids, e.g. PCR-based replicon typing (PBRT) or relaxase typing. Currently, there are 28 known plasmid types in Enterobacteriaceae distinguished by PBRT. Frequently reported plasmids [IncF, IncI, IncA/C, IncL (previously designated IncL/M), IncN and IncH] are the ones that bear the greatest variety of resistance genes. The purpose of this review is to provide an overview of all known AMR-related plasmid families in Enterobacteriaceae, the resistance genes they carry and their geographical distribution.
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Affiliation(s)
- M Rozwandowicz
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - M S M Brouwer
- Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - J Fischer
- Department of Biological Safety, Federal Institute for Risk Assessment, BfR, Berlin, Germany
| | - J A Wagenaar
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.,Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - B Gonzalez-Zorn
- Department of Animal Health and VISAVET, Complutense University of Madrid, Madrid, Spain
| | - B Guerra
- Department of Biological Safety, Federal Institute for Risk Assessment, BfR, Berlin, Germany
| | - D J Mevius
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.,Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - J Hordijk
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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10
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Hüttener M, Prieto A, Aznar S, Dietrich M, Paytubi S, Juárez A. Tetracycline alters gene expression in Salmonella strains that harbor the Tn10 transposon. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:202-209. [PMID: 29393572 DOI: 10.1111/1758-2229.12621] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this report, we show that bacterial plasmids that harbor the Tn10 transposon (i.e., the IncHI1 plasmid R27) modify expression of different Salmonella regulons responding to the presence of tetracycline (Tc) in the medium. By using as a model the Tc-dependent upregulation of the ibpAB operon (which belongs to the heat shock regulon), we have identified Tn10-tetA (coding for a Tc efflux pump) and adjacent tetC sequences as required for ibpAB upregulation. Characterization of transcripts in the tetAC region showed that tetA transcription can continue into tetC sequences, generating a long 3'UTR sequence, which can protect transcripts from RNA processing, thus increasing the expression of TetA protein. In the presence of Tc, the DnaK and IbpA chaperones are overexpressed and translocated to the periplasm and to the membrane fraction respectively. DnaK targeting unfolded proteins is known to induce heat shock by avoiding RpoH proteolysis. We correlate expression levels of Tn10-encoded TetA protein with heat shock induction in Salmonella, likely because TetA activity compromises protein secretion.
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Affiliation(s)
- M Hüttener
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - A Prieto
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - S Aznar
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - M Dietrich
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - S Paytubi
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
| | - A Juárez
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and technology, Barcelona, Spain
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11
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Liang Q, Yin Z, Zhao Y, Liang L, Feng J, Zhan Z, Wang H, Song Y, Tong Y, Wu W, Chen W, Wang J, Jiang L, Zhou D. Sequencing and comparative genomics analysis of the IncHI2 plasmids pT5282-mphA and p112298-catA and the IncHI5 plasmid pYNKP001-dfrA. Int J Antimicrob Agents 2017; 49:709-718. [DOI: 10.1016/j.ijantimicag.2017.01.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/09/2016] [Accepted: 01/22/2017] [Indexed: 01/16/2023]
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12
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Gibert M, Paytubi S, Beltrán S, Juárez A, Balsalobre C, Madrid C. Growth phase-dependent control of R27 conjugation is mediated by the interplay between the plasmid-encoded regulatory circuit TrhR/TrhY-HtdA and the cAMP regulon. Environ Microbiol 2016; 18:5277-5287. [PMID: 27768816 DOI: 10.1111/1462-2920.13579] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 10/14/2016] [Indexed: 01/06/2023]
Abstract
Plasmids of the incompatibility group HI1 (IncHI1) have been isolated from several Gram-negative pathogens and are associated with the spread of multidrug resistance. Their conjugation is tightly regulated and it is inhibited at temperatures higher than 30°C, indicating that conjugation occurs outside warm-blooded hosts. Using R27, the prototype of IncHI1 plasmids, we report that plasmid transfer efficiency in E. coli strongly depends on the physiological state of the donor cells. Conjugation frequency is high when cells are actively growing, dropping sharply when cells enter the stationary phase of growth. Accordingly, our transcriptomic assays show significant downregulation of numerous R27 genes during the stationary phase, including several tra (transfer) genes. Growth phase-dependent regulation of tra genes transcription is independent of H-NS, a silencer of horizontal gene transfer, and ppGpp and RpoS, regulators of the stationary phase, but highly dependent on the plasmid-encoded regulatory circuit TrhR/TrhY-HtdA. The metabolic sensor cAMP, whose synthesis is chromosomally encoded, is also involved in the growth phase regulation of R27 conjugation by modulating htdA expression. Our data suggest that the involvement of regulators encoded by both chromosome and plasmid are required for efficient physiological control of IncHI1 plasmid conjugation.
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Affiliation(s)
- Marta Gibert
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Sonia Paytubi
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Sergi Beltrán
- Centre Nacional d'Anàlisi Genòmica (CNAG), Parc Científic de Barcelona, Baldiri Reixac 4, Barcelona, 08028, Spain
| | - Antonio Juárez
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain.,Institut de Bioenginyeria de Catalunya (IBEC), Parc Científic de Barcelona, Baldiri Reixac 10, Barcelona, 08028, Spain
| | - Carlos Balsalobre
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
| | - Cristina Madrid
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, Barcelona, 08028, Spain
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Aviv G, Rahav G, Gal-Mor O. Horizontal Transfer of the Salmonella enterica Serovar Infantis Resistance and Virulence Plasmid pESI to the Gut Microbiota of Warm-Blooded Hosts. mBio 2016; 7:e01395-16. [PMID: 27601577 PMCID: PMC5013300 DOI: 10.1128/mbio.01395-16] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Salmonella enterica serovar Infantis is one of the prevalent salmonellae worldwide. Recently, we showed that the emergence of S Infantis in Israel was facilitated by the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Here we elucidate the ecology, transmission properties, and regulation of pESI. We show that despite its large size (~280 kb), pESI does not impose a significant metabolic burden in vitro and that it has been recently fixed in the domestic S Infantis population. pESI conjugation and the transcription of its pilus (pil) genes are inhibited at the ambient temperature (27°C) and by ≥1% bile but increased under temperatures of 37 to 41°C, oxidative stress, moderate osmolarity, and the microaerobic conditions characterizing the intestinal environment of warm-blooded animals. The pESI-encoded protein TraB and the oxygen homeostasis regulator Fnr were identified as transcriptional regulators of pESI conjugation. Using the mouse model, we show that following S Infantis infection, pESI can be horizontally transferred to the gut microbiota, including to commensal Escherichia coli strains. Possible transfer, but not persistence, of pESI was also observed into Gram-positive mouse microbiota species, especially Lactobacillus reuteri Moreover, pESI was demonstrated to further disseminate from gut microbiota to S. enterica serovar Typhimurium, in the context of gastrointestinal infection. These findings exhibit the ability of a selfish clinically relevant megaplasmid to distribute to and from the microbiota and suggest an overlooked role of the microbiota as a reservoir of mobile genetic elements and intermediator in the spread of resistance and virulence genes between commensals and pathogenic bacteria. IMPORTANCE Plasmid conjugation plays a key role in microbial evolution, enabling the acquisition of new phenotypes, including resistance and virulence. Salmonella enterica serovar Infantis is one of the ubiquitous salmonellae worldwide and a major cause of foodborne infections. Previously, we showed that the emergence of S Infantis in Israel has involved the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Recently, the emergence of another S Infantis strain carrying a pESI-like plasmid was identified in Italy, suggesting that the acquisition of pESI may be common to different emergent S Infantis populations globally. Transmission of this plasmid to other strains or bacterial species is an alarming scenario. Understanding the ecology, regulation, and transmission properties of clinically relevant plasmids and the role of the microbiota in their spreading offers a new mechanism explaining the emergence of new pathogenic and resistant biotypes and may assist in the development of appropriate surveillance and prevention measures.
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Affiliation(s)
- Gili Aviv
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Galia Rahav
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ohad Gal-Mor
- The Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Horizontal Transfer of the Salmonella enterica Serovar Infantis Resistance and Virulence Plasmid pESI to the Gut Microbiota of Warm-Blooded Hosts. mBio 2016. [PMID: 27601577 DOI: 10.1128/mbio.01395‐16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Salmonella enterica serovar Infantis is one of the prevalent salmonellae worldwide. Recently, we showed that the emergence of S Infantis in Israel was facilitated by the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Here we elucidate the ecology, transmission properties, and regulation of pESI. We show that despite its large size (~280 kb), pESI does not impose a significant metabolic burden in vitro and that it has been recently fixed in the domestic S Infantis population. pESI conjugation and the transcription of its pilus (pil) genes are inhibited at the ambient temperature (27°C) and by ≥1% bile but increased under temperatures of 37 to 41°C, oxidative stress, moderate osmolarity, and the microaerobic conditions characterizing the intestinal environment of warm-blooded animals. The pESI-encoded protein TraB and the oxygen homeostasis regulator Fnr were identified as transcriptional regulators of pESI conjugation. Using the mouse model, we show that following S Infantis infection, pESI can be horizontally transferred to the gut microbiota, including to commensal Escherichia coli strains. Possible transfer, but not persistence, of pESI was also observed into Gram-positive mouse microbiota species, especially Lactobacillus reuteri Moreover, pESI was demonstrated to further disseminate from gut microbiota to S. enterica serovar Typhimurium, in the context of gastrointestinal infection. These findings exhibit the ability of a selfish clinically relevant megaplasmid to distribute to and from the microbiota and suggest an overlooked role of the microbiota as a reservoir of mobile genetic elements and intermediator in the spread of resistance and virulence genes between commensals and pathogenic bacteria. IMPORTANCE Plasmid conjugation plays a key role in microbial evolution, enabling the acquisition of new phenotypes, including resistance and virulence. Salmonella enterica serovar Infantis is one of the ubiquitous salmonellae worldwide and a major cause of foodborne infections. Previously, we showed that the emergence of S Infantis in Israel has involved the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Recently, the emergence of another S Infantis strain carrying a pESI-like plasmid was identified in Italy, suggesting that the acquisition of pESI may be common to different emergent S Infantis populations globally. Transmission of this plasmid to other strains or bacterial species is an alarming scenario. Understanding the ecology, regulation, and transmission properties of clinically relevant plasmids and the role of the microbiota in their spreading offers a new mechanism explaining the emergence of new pathogenic and resistant biotypes and may assist in the development of appropriate surveillance and prevention measures.
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15
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Tassinari E, Aznar S, Urcola I, Prieto A, Hüttener M, Juárez A. The incC Sequence Is Required for R27 Plasmid Stability. Front Microbiol 2016; 7:629. [PMID: 27199955 PMCID: PMC4853401 DOI: 10.3389/fmicb.2016.00629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/18/2016] [Indexed: 11/15/2022] Open
Abstract
IncHI plasmids account for multiple antimicrobial resistance in Salmonella and other enterobacterial genera. These plasmids are generally very stable in their bacterial hosts. R27 is the archetype of IncHI1 plasmids. A high percentage of the R27-encoded open reading frames (ORFs) (66.7%) do not show similarity to any known ORFs. We performed a deletion analysis of all non-essential R27 DNA sequences to search for hitherto non-identified plasmid functions that might be required for plasmid stability. We report the identification of a short DNA sequence (incC) that is essential for R27 stability. That region contains several repeats (incC repeats), belongs to one of the three-plasmid replicons (R27 FIA-like) and is targeted by the R27 E protein. Deletion of the incC sequence drastically reduces R27 stability both in Escherichia coli and in Salmonella, the effect being more pronounced in this latter species. Interfering with incC–E protein interaction must lead to a reduced IncHI1 plasmid stability, and may represent a new approach to combat antimicrobial resistance.
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Affiliation(s)
| | - Sonia Aznar
- Institut de Bioenginyeria de Catalunya Barcelona, Spain
| | - Imanol Urcola
- Institut de Bioenginyeria de Catalunya Barcelona, Spain
| | - Alejandro Prieto
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona Barcelona, Spain
| | | | - Antonio Juárez
- Institut de Bioenginyeria de CatalunyaBarcelona, Spain; Departament de Microbiologia, Facultat de Biologia, Universitat de BarcelonaBarcelona, Spain
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16
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Bhutani N, Muraleedharan C, Talreja D, Rana SW, Walia S, Kumar A, Walia SK. Occurrence of Multidrug Resistant Extended Spectrum Beta-Lactamase-Producing Bacteria on Iceberg Lettuce Retailed for Human Consumption. BIOMED RESEARCH INTERNATIONAL 2015; 2015:547547. [PMID: 26064922 PMCID: PMC4433657 DOI: 10.1155/2015/547547] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 11/18/2014] [Accepted: 11/26/2014] [Indexed: 11/18/2022]
Abstract
Antibiotic resistance in bacteria is a global problem exacerbated by the dissemination of resistant bacteria via uncooked food, such as green leafy vegetables. New strains of bacteria are emerging on a daily basis with novel expanded antibiotic resistance profiles. In this pilot study, we examined the occurrence of antibiotic resistant bacteria against five classes of antibiotics on iceberg lettuce retailed in local convenience stores in Rochester, Michigan. In this study, 138 morphologically distinct bacterial colonies from 9 iceberg lettuce samples were randomly picked and tested for antibiotic resistance. Among these isolates, the vast majority (86%) demonstrated resistance to cefotaxime, and among the resistant bacteria, the majority showed multiple drug resistance, particularly against cefotaxime, chloramphenicol, and tetracycline. Three bacterial isolates (2.17%) out of 138 were extended spectrum beta-lactamase (ESBL) producers. Two ESBL producers (T1 and T5) were identified as Klebsiella pneumoniae, an opportunistic pathogen with transferable sulfhydryl variable- (SHV-) and TEM-type ESBLs, respectively. The DNA sequence analysis of the bla SHV detected in K. pneumoniae isolate T1 revealed 99% relatedness to bla SHV genes found in clinical isolates. This implies that iceberg lettuce is a potential reservoir of newly emerging and evolving antibiotic resistant bacteria and its consumption poses serious threat to human health.
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Affiliation(s)
- Natasha Bhutani
- Department of Biological Sciences, Oakland University, 375 Dodge Hall of Engineering, Rochester, MI 48309, USA
| | - Chithra Muraleedharan
- Department of Biological Sciences, Oakland University, 375 Dodge Hall of Engineering, Rochester, MI 48309, USA
| | - Deepa Talreja
- Department of Biological Sciences, Oakland University, 375 Dodge Hall of Engineering, Rochester, MI 48309, USA
- Department of Ophthalmology, Kresge Eye Institute, Wayne State University School of Medicine, 4717 Saint Antoine Street, Detroit, MI 48201, USA
| | - Sonia Walia Rana
- Department of Ophthalmology, Kresge Eye Institute, Wayne State University School of Medicine, 4717 Saint Antoine Street, Detroit, MI 48201, USA
| | - Sandeep Walia
- Department of Gastroenterology, Henry Ford Health System, Detroit, MI 48208, USA
| | - Ashok Kumar
- Department of Biological Sciences, Oakland University, 375 Dodge Hall of Engineering, Rochester, MI 48309, USA
- Department of Ophthalmology, Kresge Eye Institute, Wayne State University School of Medicine, 4717 Saint Antoine Street, Detroit, MI 48201, USA
| | - Satish K. Walia
- Department of Biological Sciences, Oakland University, 375 Dodge Hall of Engineering, Rochester, MI 48309, USA
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17
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Gibert M, Juárez A, Zechner EL, Madrid C, Balsalobre C. TrhR, TrhY and HtdA, a novel regulatory circuit that modulates conjugation of the IncHI plasmids. Mol Microbiol 2014; 94:1146-1161. [PMID: 25302406 DOI: 10.1111/mmi.12823] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2014] [Indexed: 11/28/2022]
Abstract
Bacterial conjugation promotes horizontal gene transfer and, consequently, the acquisition of new capabilities such as resistance to antimicrobial compounds and virulence related traits. Conjugative plasmids belonging to the incompatibility group HI are associated with multidrug resistance in Gram-negative pathogens. IncHI plasmid conjugation is thermodependent and all transfer-related genes are encoded in six operons (tra operons). Using R27, the prototype of IncHI1 plasmids, we reported that the plasmid-encoded factor HtdA represses four of the six tra operons. Moreover, our results indicated that other R27 factors were required for appropriate expression of the tra genes. In this report, using R27 libraries and random mutagenesis assays, two genes - trhR and trhY - have been identified as essential for the transcriptional expression of four tra operons and, accordingly, for the R27 conjugation. TrhR and TrhY are required simultaneously and their stimulatory activity is counteracted by HtdA. Functional and physical interactions between TrhR, TrhY and HtdA suggest that they form a three-element regulatory circuit that controls conjugation of IncHI plasmids. Expression studies suggest that H-NS represses conjugation at high temperature by repressing trhR expression. Remarkably, we show that this regulatory circuit is highly conserved among the IncHI plasmids.
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Affiliation(s)
- M Gibert
- Departament de Microbiologia, Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
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18
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Paytubi S, Aznar S, Madrid C, Balsalobre C, Dillon SC, Dorman CJ, Juárez A. A novel role for antibiotic resistance plasmids in facilitatingSalmonellaadaptation to non-host environments. Environ Microbiol 2013; 16:950-62. [DOI: 10.1111/1462-2920.12244] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/05/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Sonia Paytubi
- Departament de Microbiologia; Facultat de Biologia; Universitat de Barcelona; Avda. Diagonal 643 08028 Barcelona Spain
| | - Sonia Aznar
- Departament de Microbiologia; Facultat de Biologia; Universitat de Barcelona; Avda. Diagonal 643 08028 Barcelona Spain
| | - Cristina Madrid
- Departament de Microbiologia; Facultat de Biologia; Universitat de Barcelona; Avda. Diagonal 643 08028 Barcelona Spain
| | - Carlos Balsalobre
- Departament de Microbiologia; Facultat de Biologia; Universitat de Barcelona; Avda. Diagonal 643 08028 Barcelona Spain
| | - Shane C. Dillon
- Department of Microbiology; Trinity College Dublin; Dublin 2 Ireland
| | - Charles J. Dorman
- Department of Microbiology; Trinity College Dublin; Dublin 2 Ireland
| | - Antonio Juárez
- Departament de Microbiologia; Facultat de Biologia; Universitat de Barcelona; Avda. Diagonal 643 08028 Barcelona Spain
- Institut de Bioenginyeria de Catalunya (IBEC); Parc Científic de Barcelona; Baldiri Reixach 15-21 08028 Barcelona Spain
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19
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Gibert M, Juárez A, Madrid C, Balsalobre C. New insights in the role of HtdA in the regulation of R27 conjugation. Plasmid 2013; 70:61-8. [DOI: 10.1016/j.plasmid.2013.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/28/2013] [Accepted: 01/30/2013] [Indexed: 10/27/2022]
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20
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Drudge CN, Warren LA. Prokaryotic Horizontal Gene Transfer in Freshwater Lakes: Implications of Dynamic Biogeochemical Zonation. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/jep.2012.312181] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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21
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Peterson G, Kumar A, Gart E, Narayanan S. Catecholamines increase conjugative gene transfer between enteric bacteria. Microb Pathog 2011; 51:1-8. [PMID: 21419838 DOI: 10.1016/j.micpath.2011.03.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 03/02/2011] [Accepted: 03/09/2011] [Indexed: 11/24/2022]
Abstract
The ability of pathogenic bacteria to sense and respond to periods of host stress is critical to their lifestyle. Adrenaline and norepinephrine are catecholamines that mediate acute host stress in vertebrates and invertebrates. Catecholamines are also used as environmental cues to enhance growth, motility and virulence of bacterial pathogens via specific binding receptors. Incidence of multidrug resistant and highly virulent bacterial pathogens is on the rise, and majority of the genes for antimicrobial resistance (AMR) and virulence are carried on horizontally transferable genetic elements. Conjugation machinery offers an efficient method for acquisition of AMR and virulence genes, which may be responsible for propelling the evolution of pathogenic bacteria. Here we show that norepinephrine (NE) at physiological concentrations enhances horizontal gene transfer (HGT) efficiencies of a conjugative plasmid from a clinical strain of Salmonella Typhimurium to an Escherichia coli recipient in vitro. Expressions of plasmid encoded transfer (tra) genes necessary for conjugation were also significantly upregulated in the presence of NE. Phentolamine, an α-adrenergic receptor antagonist, negated the effects of NE on conjugation more strongly than propranolol, a β-adrenergic receptor antagonist. This study for the first time provides evidence that innate mediators of acute host stress may influence evolution and adaptation of bacterial pathogens.
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Affiliation(s)
- Greg Peterson
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, K-246 Mosier Hall, 1800 Denison Avenue, Manhattan, KS 66506, USA
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22
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Frost LS, Koraimann G. Regulation of bacterial conjugation: balancing opportunity with adversity. Future Microbiol 2010; 5:1057-71. [PMID: 20632805 DOI: 10.2217/fmb.10.70] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Conjugative plasmids are involved in the dissemination of important traits such as antibiotic resistance, virulence determinants and metabolic pathways involved in adapting to environmental niches, a process termed horizontal or lateral gene transfer. Conjugation is the process of transferring DNA from a donor to a recipient cell with the establishment of the incoming DNA and its cargo of genetic traits within the transconjugant. Conjugation is mediated by self-transmissible plasmids as well as phage-like sequences that have been integrated into the bacterial chromosome, such as integrative and conjugative elements (ICEs) that now include conjugative transposons. Both conjugative plasmids and ICEs can mediate the transfer of mobilizable elements by sharing their conjugative machinery. Conjugation can either be induced, usually by small molecules or peptides or by excision of the ICE from the host chromosome, or it can be tightly regulated by plasmid- and host-encoded factors. The transfer potential of these transfer regions depends on the integration of many signals in response to environmental and physiological cues. This review will focus on the mechanisms that influence transfer potential in these systems, particularly those of the IncF incompatibility group.
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Affiliation(s)
- Laura S Frost
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada.
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23
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Norman A, Hansen LH, Sørensen SJ. Conjugative plasmids: vessels of the communal gene pool. Philos Trans R Soc Lond B Biol Sci 2009; 364:2275-89. [PMID: 19571247 DOI: 10.1098/rstb.2009.0037] [Citation(s) in RCA: 314] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Comparative whole-genome analyses have demonstrated that horizontal gene transfer (HGT) provides a significant contribution to prokaryotic genome innovation. The evolution of specific prokaryotes is therefore tightly linked to the environment in which they live and the communal pool of genes available within that environment. Here we use the term supergenome to describe the set of all genes that a prokaryotic 'individual' can draw on within a particular environmental setting. Conjugative plasmids can be considered particularly successful entities within the communal pool, which have enabled HGT over large taxonomic distances. These plasmids are collections of discrete regions of genes that function as 'backbone modules' to undertake different aspects of overall plasmid maintenance and propagation. Conjugative plasmids often carry suites of 'accessory elements' that contribute adaptive traits to the hosts and, potentially, other resident prokaryotes within specific environmental niches. Insight into the evolution of plasmid modules therefore contributes to our knowledge of gene dissemination and evolution within prokaryotic communities. This communal pool provides the prokaryotes with an important mechanistic framework for obtaining adaptability and functional diversity that alleviates the need for large genomes of specialized 'private genes'.
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Affiliation(s)
- Anders Norman
- Department of Biology, Section for Evolution and Microbiology, University of Copenhagen, Copenhagen K, Denmark.
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24
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Garcillán-Barcia MP, Francia MV, de la Cruz F. The diversity of conjugative relaxases and its application in plasmid classification. FEMS Microbiol Rev 2009; 33:657-87. [PMID: 19396961 DOI: 10.1111/j.1574-6976.2009.00168.x] [Citation(s) in RCA: 375] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Bacterial conjugation is an efficient and sophisticated mechanism of DNA transfer among bacteria. While mobilizable plasmids only encode a minimal MOB machinery that allows them to be transported by other plasmids, conjugative plasmids encode a complete set of transfer genes (MOB1T4SS). The only essential ingredient of the MOB machinery is the relaxase, the protein that initiates and terminates conjugative DNA processing. In this review we compared the sequences and properties of the relaxase proteins contained in gene sequence databases. Proteins were arranged in families and phylogenetic trees constructed from the family alignments. This allowed the classification of conjugative transfer systems in six MOB families:MOB(F), MOB(H), MOB(Q), MOB(C), MOB(P) and MOB(V). The main characteristics of each family were reviewed. The phylogenetic relationships of the coupling proteins were also analysed and resulted in phylogenies congruent to those of the cognate relaxases. We propose that the sequences of plasmid relaxases can be used for plasmid classification. We hope our effort will provide researchers with a useful tool for further mining and analysing the plasmid universe both experimentally and in silico.
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Affiliation(s)
- María Pilar Garcillán-Barcia
- Departamento de Biología Molecular e Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-CSIC-IDICAN, Santander, Spain
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25
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Drlica K, Hiasa H, Kerns R, Malik M, Mustaev A, Zhao X. Quinolones: action and resistance updated. Curr Top Med Chem 2009; 9:981-98. [PMID: 19747119 PMCID: PMC3182077 DOI: 10.2174/156802609789630947] [Citation(s) in RCA: 235] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 07/30/2009] [Indexed: 11/22/2022]
Abstract
The quinolones trap DNA gyrase and DNA topoisomerase IV on DNA as complexes in which the DNA is broken but constrained by protein. Early studies suggested that drug binding occurs largely along helix-4 of the GyrA (gyrase) and ParC (topoisomerase IV) proteins. However, recent X-ray crystallography shows drug intercalating between the -1 and +1 nucleotides of cut DNA, with only one end of the drug extending to helix-4. These two models may reflect distinct structural steps in complex formation. A consequence of drug-enzyme-DNA complex formation is reversible inhibition of DNA replication; cell death arises from subsequent events in which bacterial chromosomes are fragmented through two poorly understood pathways. In one pathway, chromosome fragmentation stimulates excessive accumulation of highly toxic reactive oxygen species that are responsible for cell death. Quinolone resistance arises stepwise through selective amplification of mutants when drug concentrations are above the MIC and below the MPC, as observed with static agar plate assays, dynamic in vitro systems, and experimental infection of rabbits. The gap between MIC and MPC can be narrowed by compound design that should restrict the emergence of resistance. Resistance is likely to become increasingly important, since three types of plasmid-borne resistance have been reported.
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Affiliation(s)
- Karl Drlica
- Public Health Research Institute, New Jersey Medical School, UMDNJ, 225 Warren Street, Newark, NJ 07103, USA.
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26
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Schumann W. Chapter 7 Temperature Sensors of Eubacteria. ADVANCES IN APPLIED MICROBIOLOGY 2009; 67:213-56. [DOI: 10.1016/s0065-2164(08)01007-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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27
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Structural biology of plasmid partition: uncovering the molecular mechanisms of DNA segregation. Biochem J 2008; 412:1-18. [PMID: 18426389 DOI: 10.1042/bj20080359] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
DNA segregation or partition is an essential process that ensures stable genome transmission. In prokaryotes, partition is best understood for plasmids, which serve as tractable model systems to study the mechanistic underpinnings of DNA segregation at a detailed atomic level owing to their simplicity. Specifically, plasmid partition requires only three elements: a centromere-like DNA site and two proteins: a motor protein, generally an ATPase, and a centromere-binding protein. In the first step of the partition process, multiple centromere-binding proteins bind co-operatively to the centromere, which typically consists of several tandem repeats, to form a higher-order nucleoprotein complex called the partition complex. The partition complex recruits the ATPase to form the segrosome and somehow activates the ATPase for DNA separation. Two major families of plasmid par systems have been delineated based on whether they utilize ATPase proteins with deviant Walker-type motifs or actin-like folds. In contrast, the centromere-binding proteins show little sequence homology even within a given family. Recent structural studies, however, have revealed that these centromere-binding proteins appear to belong to one of two major structural groups: those that employ helix-turn-helix DNA-binding motifs or those with ribbon-helix-helix DNA-binding domains. The first structure of a higher-order partition complex was recently revealed by the structure of pSK41 centromere-binding protein, ParR, bound to its centromere site. This structure showed that multiple ParR ribbon-helix-helix motifs bind symmetrically to the tandem centromere repeats to form a large superhelical structure with dimensions suitable for capture of the filaments formed by the actinlike ATPases. Surprisingly, recent data indicate that the deviant Walker ATPase proteins also form polymer-like structures, suggesting that, although the par families harbour what initially appeared to be structurally and functionally divergent proteins, they actually utilize similar mechanisms of DNA segregation. Thus, in the present review, the known Par protein and Par-protein complex structures are discussed with regard to their functions in DNA segregation in an attempt to begin to define, at a detailed atomic level, the molecular mechanisms involved in plasmid segregation.
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Gunton JE, Gilmour MW, Alonso G, Taylor DE. Subcellular localization and functional domains of the coupling protein, TraG, from IncHI1 plasmid R27. Microbiology (Reading) 2005; 151:3549-3561. [PMID: 16272378 DOI: 10.1099/mic.0.28255-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial conjugation is a horizontal gene transfer event mediated by the type IV secretion system (T4SS) encoded by bacterial plasmids. Within the T4SS, the coupling protein plays an essential role in linking the membrane-associated pore-forming proteins to the cytoplasmic, DNA-processing proteins. TraG is the coupling protein encoded by the incompatibility group HI plasmids. A hallmark feature of the IncHI plasmids is optimal conjugative transfer at 30 °C and an inability to transfer at 37 °C. Transcriptional analysis of the transfer region 1 (Tra1) of R27 has revealed thattraGis transcribed in a temperature-dependent manner, with significantly reduced levels of expression at 37 °C as compared to expression at 30 °C. The R27 coupling protein contains nucleoside triphosphate (NTP)-binding domains, the Walker A and Walker B boxes, which are well conserved among this family of proteins. Site-specific mutagenesis within these motifs abrogated the conjugative transfer of R27 into recipient cells. Mutational analysis of the TraG periplasmic-spanning residues, in conjunction with bacterial two-hybrid and immunoprecipitation analysis, determined that this region is essential for a successful interaction with the T4SS protein TrhB. Further characterization of TraG by immunofluorescence studies revealed that the R27 coupling protein forms membrane-associated fluorescent foci independent of R27 conjugative proteins. These foci were found at discrete positions within the cell periphery. These results allow the definition of domains within TraG that are involved in conjugative transfer, and determination of the cellular location of the R27 coupling protein.
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Affiliation(s)
- James E Gunton
- Department of Medical Microbiology and Immunology, 1-63 Medical Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2R3
| | - Matthew W Gilmour
- National Microbiology Laboratory, Health Canada, Winnipeg, Manitoba, Canada R3E 3R2
| | - Guillermina Alonso
- Instituto de Biologia Experimental, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela
| | - Diane E Taylor
- Department of Medical Microbiology and Immunology, 1-63 Medical Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2R3
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