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Rodrigues SH, Nunes GD, Soares GG, Ferreira RL, Damas MSF, Laprega PM, Shilling RE, Campos LC, da Costa AS, Malavazi I, da Cunha AF, Pranchevicius MCDS. First report of coexistence of blaKPC-2 and blaNDM-1 in carbapenem-resistant clinical isolates of Klebsiella aerogenes in Brazil. Front Microbiol 2024; 15:1352851. [PMID: 38426065 PMCID: PMC10903355 DOI: 10.3389/fmicb.2024.1352851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/26/2024] [Indexed: 03/02/2024] Open
Abstract
Klebsiella aerogenes is an important opportunistic pathogen with the potential to develop resistance against last-line antibiotics, such as carbapenems, limiting the treatment options. Here, we investigated the antibiotic resistance profiles of 10 K. aerogenes strains isolated from patient samples in the intensive-care unit of a Brazilian tertiary hospital using conventional PCR and a comprehensive genomic characterization of a specific K. aerogenes strain (CRK317) carrying both the blaKPC-2 and blaNDM-1 genes simultaneously. All isolates were completely resistant to β-lactam antibiotics, including ertapenem, imipenem, and meropenem with differencing levels of resistance to aminoglycosides, quinolones, and tigecycline also observed. Half of the strains studied were classified as multidrug-resistant. The carbapenemase-producing isolates carried many genes of interest including: β-lactams (blaNDM-1, blaKPC-2, blaTEM-1, blaCTX-M-1 group, blaOXA-1 group and blaSHVvariants in 20-80% of the strains), aminoglycoside resistance genes [aac(6')-Ib and aph(3')-VI, 70 and 80%], a fluoroquinolone resistance gene (qnrS, 80%), a sulfonamide resistance gene (sul-2, 80%) and a multidrug efflux system transporter (mdtK, 70%) while all strains carried the efflux pumps Acr (subunit A) and tolC. Moreover, we performed a comprehensive genomic characterization of a specific K. aerogenes strain (CRK317) carrying both the blaKPC-2 and blaNDM-1 genes simultaneously. The draft genome assembly of the CRK317 had a total length of 5,462,831 bp and a GC content of 54.8%. The chromosome was found to contain many essential genes. In silico analysis identified many genes associated with resistance phenotypes, including β-lactamases (blaOXA-9, blaTEM-1, blaNDM-1, blaCTX-M-15, blaAmpC-1, blaAmpC-2), the bleomycin resistance gene (bleMBL), an erythromycin resistance methylase (ermC), aminoglycoside-modifying enzymes [aac(6')-Ib, aadA/ant(3")-Ia, aph(3')-VI], a sulfonamide resistance enzyme (sul-2), a chloramphenicol acetyltransferase (catA-like), a plasmid-mediated quinolone resistance protein (qnrS1), a glutathione transferase (fosA), PEtN transferases (eptA, eptB) and a glycosyltransferase (arnT). We also detected 22 genomic islands, eight families of insertion sequences, two putative integrative and conjugative elements with a type IV secretion system, and eight prophage regions. This suggests the significant involvement of these genetic structures in the dissemination of antibiotic resistance. The results of our study show that the emergence of carbapenemase-producing K. aerogenes, co-harboring blaKPC-2 and blaNDM-1, is a worrying phenomenon which highlights the importance of developing strategies to detect, prevent, and control the spread of these microorganisms.
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Affiliation(s)
- Saulo Henrique Rodrigues
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Gustavo Dantas Nunes
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Gabriela Guerrera Soares
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Roumayne Lopes Ferreira
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | | | - Pedro Mendes Laprega
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | | | | | - Andrea Soares da Costa
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
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Gowripriya T, Meharaj Afrin K, Paurna M, Yashwanth R, Bhaskar JP, Suresh R, Balamurugan K. Regulation of miR-61 and col-19 via TGF-β and Notch signalling in Caenorhabditis elegans against Klebsiella aerogenes infection. Microb Pathog 2024; 186:106505. [PMID: 38122874 DOI: 10.1016/j.micpath.2023.106505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/06/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Klebsiella aerogenes, previously known as Enterobacter aerogenes, is a gram-negative bacterium typically present in the gastrointestinal tract. While numerous studies reported the pathogenicity and drug resistance of this bacterium there remains a lack of comprehensive research on K. aerogenes induced alterations in the host cellular mechanisms. In this study, we identify a previously uncharacterized C. elegans miR-61 that defines an evolutionarily conserved miRNA important for development and innate immunity regulation through Notch and TGF-β signaling pathway. We employed C. elegans wild-type (N2) as well as mutant strains, such as TGF-β (sma-6) and notch-signaling pathway mutants (adm-4 and mir-61). Our results have demonstrated that the K. aerogenes infected mutants exhibited significantly reduced survival rate, reduced pharyngeal pumping, altered swimming and chemotactic behavior. Moreover, K. aerogenes affects the healthspan by increasing ROS level in the mutants. The gene expression analysis revealed that K. aerogenes upregulated egl-30, tph-1 and sod-1 in adm-4, mir-61 mutants not in sma-6. The in-silico analysis indicated an interaction between mir-61 and col-19, which was confirmed by the upregulation of miR-61 expression and the downregulation of col-19 in sma-6, adm-4, and wild-type strains. These findings suggest that C. elegans activates mir-61 and col-19 regulation through the Notch and TGF-β signaling pathway against K. aerogenes infection.
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Affiliation(s)
- Thirumugam Gowripriya
- Department of Biotechnology, Science Campus, Alagappa University, Karaikudi, 630 003, India.
| | | | - Manikandan Paurna
- Department of Biotechnology, Science Campus, Alagappa University, Karaikudi, 630 003, India.
| | - Radhakrishnan Yashwanth
- ITC Life Sciences and Technology Centre, Peenya Industrial Area, Bangalore, 560 058, Karnataka, India.
| | - James Prabhanand Bhaskar
- ITC Life Sciences and Technology Centre, Peenya Industrial Area, Bangalore, 560 058, Karnataka, India.
| | - Ramamurthi Suresh
- ITC Life Sciences and Technology Centre, Peenya Industrial Area, Bangalore, 560 058, Karnataka, India.
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Zhou G, Wang Q, Wang Y, Wen X, Peng H, Peng R, Shi Q, Xie X, Li L. Outer Membrane Porins Contribute to Antimicrobial Resistance in Gram-Negative Bacteria. Microorganisms 2023; 11:1690. [PMID: 37512863 PMCID: PMC10385648 DOI: 10.3390/microorganisms11071690] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
Gram-negative bacteria depend on their cell membranes for survival and environmental adaptation. They contain two membranes, one of which is the outer membrane (OM), which is home to several different outer membrane proteins (Omps). One class of important Omps is porins, which mediate the inflow of nutrients and several antimicrobial drugs. The microorganism's sensitivity to antibiotics, which are predominantly targeted at internal sites, is greatly influenced by the permeability characteristics of porins. In this review, the properties and interactions of five common porins, OmpA, OmpC, OmpF, OmpW, and OmpX, in connection to porin-mediated permeability are outlined. Meanwhile, this review also highlighted the discovered regulatory characteristics and identified molecular mechanisms in antibiotic penetration through porins. Taken together, uncovering porins' functional properties will pave the way to investigate effective agents or approaches that use porins as targets to get rid of resistant gram-negative bacteria.
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Affiliation(s)
- Gang Zhou
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Qian Wang
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yingsi Wang
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xia Wen
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Hong Peng
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Ruqun Peng
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Qingshan Shi
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xiaobao Xie
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Liangqiu Li
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
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Li Y, Liang W, Li C. Exogenous adenosine and/or guanosine enhances tetracycline sensitivity of persister cells. Microbiol Res 2023; 270:127321. [PMID: 36773473 DOI: 10.1016/j.micres.2023.127321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/25/2023] [Accepted: 02/04/2023] [Indexed: 02/11/2023]
Abstract
Vibrio splendidus is an opportunistic pathogen, its pathogenicity continues to be a major aquaculture disease infection problem in many parts of the world. Bacteria can form dormant and persister cells, which may be responsible for the difficulty in treating latent infections. Bacterial persister cells are a small subpopulation with high phenotypic heterogeneity that have the ability to persist in response to high concentrations of antibiotics. In our previous work, we have confirmed tetracycline could induce V. splendidus AJ01 persister cells formation. Here, we show that exogenous adenosine and/or guanosine supply restores susceptibility of AJ01 persister cells to tetracycline, leading to effective killing of this persist subpopulation upon wake-up. Mechanistically, exogenous adenosine and/or guanosine promotes the intracellular ATP level, reduces percentage of cells with protein aggresomes, and destroys membrane stability. In addition, when cells were exposed to tetracycline, we found that cells with small nucleocytoplasmic ratio is easy to survive. Overall, our results support that exogenous adenosine or guanosine could be an effective strategy for treating infections with antibiotic-persist bacteria via regulating persisters cells formation.
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Affiliation(s)
- Yanan Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo 315211, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, PR China
| | - Weikang Liang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo 315211, PR China
| | - Chenghua Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo 315211, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, PR China.
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Liu W, Xu Y, Slaveykova VI. Oxidative stress induced by sub-lethal exposure to copper as a mediator in development of bacterial resistance to antibiotics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 860:160516. [PMID: 36470380 DOI: 10.1016/j.scitotenv.2022.160516] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
Limited information exists on how bacterial resistance to antibiotics is acquired and altered in response to short-term metal stress, and what the prevailing pathways are. Here the precursor mechanisms of development of bacterial antibiotic resistance mediated by oxidative stress induce under sub-lethal Cu2+ exposure were explored. The results showed that the overall level of antibiotic resistance in wild-type Escherichia coli and antibiotic-resistant E. coli was enhanced under 4 and 20 mg/L Cu2+ exposure, as demonstrated by the 2- to 8-fold increase in minimum inhibitory concentration (MIC). The MIC correlated with the increase of the cellular ROS generation and the enhancement of the antioxidant enzyme activity (p < 0.05), suggesting that changes in antibiotic resistance under sub-lethal Cu2+ exposure could be associated with oxidative stress. Likewise, enhanced cell membrane permeability and an increase in the number of bacteria entering the viable but non culturable (VBNC) state contributed to bacterial resistance to antibiotics. Moreover, the variance partitioning analysis demonstrated that the alterations of the antibiotic resistance phenotype of wild-type E. coli was mainly caused by oxidative stress-mediated increase in cell membrane permeability and entry into the VBNC state. The development of antibiotic resistance in resistant E. coli was primarily attributed to changes in the abundance and horizontal transfer ability of its antibiotic resistance genes, both of which contributed up to 20 %. Taken together the results allowed to propose a conseptual scheme on developing bacterial antibiotic resistance mediated by oxidative stress under sub-lethal Cu2+ exposure. This result provided a strong basis for reduction of early bacterial resistance.
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Affiliation(s)
- Wei Liu
- Environmental Biogeochemistry and Ecotoxicology, Department F.A. Forel for Environmental and Aquatic Sciences, Faculty of Sciences, University of Geneva, Bvd. Carl-Vogt 66, 1211 Geneva, Switzerland
| | - Yan Xu
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, 300191, Fukang Road 31, Tianjin, China.
| | - Vera I Slaveykova
- Environmental Biogeochemistry and Ecotoxicology, Department F.A. Forel for Environmental and Aquatic Sciences, Faculty of Sciences, University of Geneva, Bvd. Carl-Vogt 66, 1211 Geneva, Switzerland.
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Parker JK, Gu R, Estrera GA, Kirkpatrick B, Rose DT, Mavridou DAI, Mondy KE, Davies BW. Carbapenem-Resistant and ESBL-Producing Enterobacterales Emerging in Central Texas. Infect Drug Resist 2023; 16:1249-1261. [PMID: 36891378 PMCID: PMC9987243 DOI: 10.2147/idr.s403448] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 02/24/2023] [Indexed: 03/06/2023] Open
Abstract
Purpose Carbapenem-resistant Enterobacterales (CRE) are subject to intense global monitoring in an attempt to maintain awareness of prevalent and emerging resistance mechanisms and to inform treatment and infection prevention strategies. CRE and extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales are not usually examined collectively in regards to their shared pool of resistance determinants. Here, we genetically and phenotypically assess clinical isolates of CRE and extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales in the growing region of Central Texas, where CRE are emergent and occurrence of non-carbapenemase-producing-CRE (non-CP-CRE) infections is increasing. Methods CRE (n=16) and ESBL-producing Enterobacterales (n=116) isolates were acquired from a regional hospital in Central Texas between December 2018 and January 2020. Isolates were assessed genetically and phenotypically using antibiotic susceptibility testing, targeted PCR, and whole genome sequencing. Results CRE infections are increasing in incidence in Central Texas, and Klebsiella pneumoniae is causing the majority of these infections. Moreover, K. pneumoniae sequence type (ST) 307 is commonly found among both non-CP-CRE and EBSL-producing strains. Isolates carry similar plasmids harboring the gene for the ESBL CTX-M-15 and belong to the global lineage, rather than the Texas lineage, of ST307. Antibiotic resistance profiles, sequence data, and clinical records suggest that porin mutations may promote the transition of ST307 isolates from ESBL-producing to non-CP-CRE. In addition to antibiotic resistance mechanisms, several CRE isolates harbor active colicinogenic plasmids, which might influence the competitiveness of these bacteria during patient colonization. Conclusion K. pneumoniae of the global ST307 lineage is circulating in Central Texas and is responsible for both non-CP CRE and ESBL-producing Enterobacterales infections. Enhanced surveillance is needed to understand the possible routes for the emergence of non-CP-CRE from EBSL-producing strains.
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Affiliation(s)
- Jennifer K Parker
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Richard Gu
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Gregory A Estrera
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | | | - Dusten T Rose
- Department of Pharmacy, Ascension Seton, Dell Seton Medical Center at The University of Texas, Austin, TX, USA
| | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.,John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, TX, USA
| | - Kristin E Mondy
- Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Bryan W Davies
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA.,John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, TX, USA
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Efflux-Mediated bile Resistance in Gram-Positive Pathogens. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2022. [DOI: 10.22207/jpam.16.1.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gram-positive pathogens are causing many serious infections that affect humans and result in mild to severe diseases worldwide. In order to survive and initiate infection, enteric pathogens must resist the physiochemical defence factors in the human intestinal tract. One of these defence factors is bile, a potent antibacterial like compound in the intestine. Efflux pumps are the important mechanism by which bacteria resist antibacterial agents such as bile. Efflux of antimicrobial substances outside the bacterial cell is considered as a key factor for intestinal colonization and virulence of enteric pathogens. This paper will review the research conducted on efflux–mediated bile resistance in Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis and Clostridium perfringens. These bacteria colonize in the human & animal gastrointestinal tract and they have a multiple mechanism to resist the innate defences in the gut and antibacterial activity of bile. However, bile resistance in these bacteria is not fully understood. The evidence from this review suggests that Gram-positive pathogens have the ability to active transport of bile. Further research is needed to know how these pathogens sense bile and how bile regulates its virulence factor. In general, therefore, it seems that understanding the specific mechanism of bile resistance in enteric bacteria including gram-positive pathogens may involve in the development of novel strategies to control and treatment of gastrointestinal infections.
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Clinical Status of Efflux Resistance Mechanisms in Gram-Negative Bacteria. Antibiotics (Basel) 2021; 10:antibiotics10091117. [PMID: 34572699 PMCID: PMC8467137 DOI: 10.3390/antibiotics10091117] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/05/2021] [Accepted: 09/15/2021] [Indexed: 01/25/2023] Open
Abstract
Antibiotic efflux is a mechanism that is well-documented in the phenotype of multidrug resistance in bacteria. Efflux is considered as an early facilitating mechanism in the bacterial adaptation face to the concentration of antibiotics at the infectious site, which is involved in the acquirement of complementary efficient mechanisms, such as enzymatic resistance or target mutation. Various efflux pumps have been described in the Gram-negative bacteria most often encountered in infectious diseases and, in healthcare-associated infections. Some are more often involved than others and expel virtually all families of antibiotics and antibacterials. Numerous studies report the contribution of these pumps in resistant strains previously identified from their phenotypes. The authors characterize the pumps involved, the facilitating antibiotics and those mainly concerned by the efflux. However, today no study describes a process for the real-time quantification of efflux in resistant clinical strains. It is currently necessary to have at hospital level a reliable and easy method to quantify the efflux in routine and contribute to a rational choice of antibiotics. This review provides a recent overview of the prevalence of the main efflux pumps observed in clinical practice and provides an idea of the prevalence of this mechanism in the multidrug resistant Gram-negative bacteria. The development of a routine diagnostic tool is now an emergency need for the proper application of current recommendations regarding a rational use of antibiotics.
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Engineering nanoscale hierarchical morphologies and geometrical shapes for microbial inactivation in aqueous solution. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 122:111844. [PMID: 33641886 DOI: 10.1016/j.msec.2020.111844] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 11/29/2020] [Accepted: 12/27/2020] [Indexed: 01/09/2023]
Abstract
Here, we study the effect of hierarchical and one-dimensional (1D) metal oxide nanorods (H-NRs) such as γ-Al2O3, β-MnO2, and ZnO as microbial inhibitors on the antimicrobial efficiency in aqueous solution. These microbial inhibitors are fabricated in a diverse range of nanoscale hierarchical morphologies and geometrical shapes that have effective surface exposure, and well-defined 1D orientation. For instance, γ-Al2O3 H-NRs with 20 nm width and ˂0.5 μm length are grown dominantly in the [400] direction. The wurtzite structures of β-MnO2 H-NRs with 30 nm width and 0.5-1 μm length are preferentially oriented in the [100] direction. Longitudinal H-NRs with a width of 40 nm and length of 1 μm are controlled with ZnO wurtzite structure and grown in [0001] direction. The antimicrobial efficiency of H-NRs was evaluated through experimental assays using a set of microorganisms (Gram-positive Staphylococcus aureus, Bacillus thuriginesis, and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Minimal inhibitory and minimum bactericidal concentrations (MIC and MBC) were determined. These 1D H-NRs exhibited antibacterial activity against all the used strains. The active surface exposure sites of H-NRs play a key role in the strong interaction with the thiol units of vital bacterial enzymes, leading to microbial inactivation. Our finding indicates that the biological effect of the H-NR surface planes on microbial inhibition is decreased in the order of [400]-γ-Al2O3 > [100]-β-MnO2 > [0001]-ZnO geometrics. The lowest key values including MIC (1.146 and 0.250 μg/mL), MBC (1.146, 0.313 μg/mL), and MIC/MFC (0.375 and 0.375 μg/mL) are achieved for [400]-plane γ-Al2O3 surfaces when tested against Gram-positive and -negative bacteria, respectively. Among the three H-NRs, the smallest diameter size and length, the largest surface area, and the active exposure [400] direction of γ-Al2O3 H-NRs could provide the highest microbial inactivation.
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Mishra M, Panda S, Barik S, Sarkar A, Singh DV, Mohapatra H. Antibiotic Resistance Profile, Outer Membrane Proteins, Virulence Factors and Genome Sequence Analysis Reveal Clinical Isolates of Enterobacter Are Potential Pathogens Compared to Environmental Isolates. Front Cell Infect Microbiol 2020; 10:54. [PMID: 32154188 PMCID: PMC7047878 DOI: 10.3389/fcimb.2020.00054] [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: 12/08/2019] [Accepted: 01/31/2020] [Indexed: 01/02/2023] Open
Abstract
Outer membrane proteins (OMPs) of gram-negative bacteria play an important role in mediating antibacterial resistance, bacterial virulence and thus affect pathogenic ability of the bacteria. Over the years, prevalence of environmental antibiotic resistant organisms, their transmission to clinics and ability to transfer resistance genes, have been studied extensively. Nevertheless, how successful environmental bacteria can be in establishing as pathogenic bacteria under clinical setting, is less addressed. In the present study, we utilized an integrated approach of investigating the antibiotic resistance profile, presence of outer membrane proteins and virulence factors to understand extent of threat posed due to multidrug resistant environmental Enterobacter isolates. Also, we investigated clinical Enterobacter isolates and compared the results thereof. Results of the study showed that multidrug resistant environmental Enterobacter isolates lacked OmpC, lacked cell invasion abilities and exhibited low reactive oxygen species (ROS) production in neutrophils. In contrast, clinical isolates possessed OmpF, exhibited high invasive and adhesive property and produced higher amounts of ROS in neutrophils. These attributes indicated limited pathogenic potential of environmental Enterobacter isolates. Informations obtained from whole genome sequence of two representative bacterial isolates from environment (DL4.3) and clinical sources (EspIMS6) corroborated well with the observed results. Findings of the present study are significant as it highlights limited fitness of multidrug resistant environmental Enterobacter isolates.
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Affiliation(s)
- Mitali Mishra
- School of Biological Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
| | - Sasmita Panda
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Susmita Barik
- Trident School of Biotech Sciences, Trident Academy of Creative and Technology, Bhubaneswar, India
| | - Arup Sarkar
- Trident School of Biotech Sciences, Trident Academy of Creative and Technology, Bhubaneswar, India
| | - Durg Vijai Singh
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Harapriya Mohapatra
- School of Biological Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar, India.,Homi Bhabha National Institute (HBNI), Mumbai, India
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Porins and small-molecule translocation across the outer membrane of Gram-negative bacteria. Nat Rev Microbiol 2019; 18:164-176. [DOI: 10.1038/s41579-019-0294-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2019] [Indexed: 02/07/2023]
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12
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Cai Y, Chen C, Zhao M, Yu X, Lan K, Liao K, Guo P, Zhang W, Ma X, He Y, Zeng J, Chen L, Jia W, Tang YW, Huang B. High Prevalence of Metallo-β-Lactamase-Producing Enterobacter cloacae From Three Tertiary Hospitals in China. Front Microbiol 2019; 10:1610. [PMID: 31447788 PMCID: PMC6697253 DOI: 10.3389/fmicb.2019.01610] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 06/27/2019] [Indexed: 11/17/2022] Open
Abstract
Enterobacter cloacae has recently emerged as one of the most common carbapenem-resistant Enterobacteriaceae. The emergence and spread of metallo-β-lactamase-producing E. cloacae have posed an immediate threat globally. Here, we investigated the molecular characteristics of 84 carbapenem-resistant Enterobacter cloacae (CREL) collected from three tertiary hospitals in China between 2012 and 2016. Species identification and antimicrobial susceptibility testing were performed using a VITEK-2 system. Carbapenems, polymyxins B, and tigecycline were tested by broth microdilution method. The carbapenem in activation method (CIM) and cefoxitin three-dimensional test were used to detect carbapenemase and AmpC β-lactamase, respectively. Isolates were screened for β-lactam resistance genes by PCR, and expression of ompC and ompF was determined by qRT-PCR. Genetic relatedness was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST), while selected isolates were subjected to whole-genome sequencing. Among the 84 CREL isolates, 50 (59.5%) were detected as carbapenemase producers. NDM-1 was the dominant carbapenemase (80.0%), followed by IMP-26 (8.0%) and IMP-4 (6.0%). Notably, we identified the first NDM-1 and IMP-1 co-producing E. cloacae, carrying plasmids of several incompatibility (Inc) groups, including IncHI2, IncHI2A, and IncN. Most isolates showed decreased expression of ompC and/or ompF, and contained a broad distribution of ESBLs and AmpC β-lactamases. These findings suggested that different molecular mechanisms, including carbapenemase, ESBL and/or AmpC plus loss of porins, have contributed to carbapenem resistance. The blaNDM−1-harboring plasmids contained highly conserved gene environment around blaNDM−1 (blaNDM−1-bleMBL-trpF-dsbD-cutA1-groES-groEL), which could be associated with the potential dissemination of blaNDM−1. IMP-type MBL was located within a variety of integrons and usually contained various gene cassettes encoding multidrug resistance. These isolates produced 54 different pulsotypes, and were classified into 42 STs by MLST. Nineteen blaNDM−1-positive E. cloacae isolates obtained from Ningxia had the same pulsotype (PFGE type 1), belonging to ST78 within clonal complex 74 (CC74). The plasmid-based replicon typing indicated that IncX3 plasmids mediated the dissemination of blaNDM−1 among these homologous strains. This is the first report on the outbreak of NDM-1-producing E. cloacae ST78 with contribution of IncX3 plasmids in Northwestern China. There's an immediate need to intensify surveillance attentively to prevent and control the further spread of NDM-1 in China.
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Affiliation(s)
- Yimei Cai
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Cha Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Laboratory Medicine, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Mei Zhao
- Department of Laboratory Medicine, Ningxia Hospital of Ningxia Medical University, Yinchuan, China
| | - Xuegao Yu
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Kai Lan
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Laboratory Medicine, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Kang Liao
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Penghao Guo
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Weizheng Zhang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Laboratory Medicine, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Xingyan Ma
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yuting He
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jianming Zeng
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Laboratory Medicine, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Liang Chen
- Public Health Research Institute Tuberculosis Center, New Jersey Medical School, Rutgers University, Newark, NJ, United States
| | - Wei Jia
- Department of Laboratory Medicine, Ningxia Hospital of Ningxia Medical University, Yinchuan, China
| | - Yi-Wei Tang
- Department of Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, United States.,Department of Pathology and Laboratory Medicine, Weill Medical College of Cornell University, New York, NY, United States
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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Enterobacter spp.: Update on Taxonomy, Clinical Aspects, and Emerging Antimicrobial Resistance. Clin Microbiol Rev 2019; 32:32/4/e00002-19. [PMID: 31315895 DOI: 10.1128/cmr.00002-19] [Citation(s) in RCA: 239] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The genus Enterobacter is a member of the ESKAPE group, which contains the major resistant bacterial pathogens. First described in 1960, this group member has proven to be more complex as a result of the exponential evolution of phenotypic and genotypic methods. Today, 22 species belong to the Enterobacter genus. These species are described in the environment and have been reported as opportunistic pathogens in plants, animals, and humans. The pathogenicity/virulence of this bacterium remains rather unclear due to the limited amount of work performed to date in this field. In contrast, its resistance against antibacterial agents has been extensively studied. In the face of antibiotic treatment, it is able to manage different mechanisms of resistance via various local and global regulator genes and the modulation of the expression of different proteins, including enzymes (β-lactamases, etc.) or membrane transporters, such as porins and efflux pumps. During various hospital outbreaks, the Enterobacter aerogenes and E. cloacae complex exhibited a multidrug-resistant phenotype, which has stimulated questions about the role of cascade regulation in the emergence of these well-adapted clones.
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14
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Next-Generation-Sequencing-Based Hospital Outbreak Investigation Yields Insight into Klebsiella aerogenes Population Structure and Determinants of Carbapenem Resistance and Pathogenicity. Antimicrob Agents Chemother 2019; 63:AAC.02577-18. [PMID: 30910904 DOI: 10.1128/aac.02577-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/21/2019] [Indexed: 02/08/2023] Open
Abstract
Klebsiella aerogenes is a nosocomial pathogen associated with drug resistance and outbreaks in intensive care units. In a 5-month period in 2017, we experienced an increased incidence of cultures for carbapenem-resistant K. aerogenes (CR-KA) from an adult cardiothoracic intensive care unit (CICU) involving 15 patients. Phylogenomic analysis following whole-genome sequencing (WGS) identified the outbreak CR-KA isolates to group together as a tight monoclonal cluster (with no more than six single nucleotide polymorphisms [SNPs]), suggestive of a protracted intraward transmission event. No clonal relationships were identified between the CICU CR-KA strains and additional hospital CR-KA patient isolates from different wards and/or previous years. Carbapenemase-encoding genes and drug-resistant plasmids were absent in the outbreak strains, and carbapenem resistance was attributed to mutations impacting AmpD activity and membrane permeability. The CICU outbreak strains harbored an integrative conjugative element (ICE) which has been associated with pathogenic Klebsiella pneumoniae lineages (ICEKp10). Comparative genomics with global K. aerogenes genomes showed our outbreak strains to group closely with global sequence type 4 (ST4) strains, which, along with ST93, likely represent dominant K. aerogenes lineages associated with human infections. For poorly characterized pathogens, scaling analyses to include sequenced genomes from public databases offer the opportunity to identify emerging trends and dominant clones associated with specific attributes, syndromes, and geographical locations.
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15
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Espinal P, Pantel A, Rolo D, Marti S, López-Rojas R, Smani Y, Pachón J, Vila J, Lavigne JP. Relationship Between Different Resistance Mechanisms and Virulence in Acinetobacter baumannii. Microb Drug Resist 2019; 25:752-760. [PMID: 30632884 DOI: 10.1089/mdr.2018.0182] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Aim: This study analyzed the virulence of several Acinetobacter baumannii strains expressing different resistance mechanisms using the Caenorhabditis elegans infection model. Results: Strains susceptible/resistant to carbapenems (presenting class D (OXA-23, OXA-24), class B metallo-β-lactamase (MBL) (NDM-1), penicillin binding protein (PBP) altered and decreased expression of Omp 33-36 kDa) and isogenic A. baumannii strains susceptible/resistant to colistin (presenting loss of lipopolysaccharide (LPS) and pmrA mutations) were included to evaluate the virulence using the C. elegans infection model. The nematode killing assay, bacterial ingestion in worms, and bacterial lawn avoidance assay were performed with the Fer-15 mutant line. A. baumannii strains generally presented low virulence, showing no difference between carbapenem-resistant strains (expressing class D, MBLs, or altered PBP) and their isogenic susceptible strains. In contrast, the absence of the Omp 33-36 kDa protein in the knockout was associated with a decrease of virulence, and a significant difference was observed between colistin-resistant mutants and their susceptible counterpart when the mechanism of resistance was associated with the loss of LPS but not with its modification. Conclusions: Resistance to carbapenems in A. baumannii associated with the production of OXA-type or NDM-type enzymes does not seem to affect their virulence in the C. elegans infection model. In contrast, the presence of Omp 33-36 kDa, and high level resistance to colistin related with the loss of LPS, might contribute with the virulence profile in A. baumannii.
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Affiliation(s)
- Paula Espinal
- 1 Barcelona Institute for Global Health (ISGlobal) Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,2 National Institute of Health and Medical Research, U1047, Montpellier University, Nîmes, France
| | - Alix Pantel
- 2 National Institute of Health and Medical Research, U1047, Montpellier University, Nîmes, France.,3 Department of Microbiology, University Hospital Nîmes, Nîmes, France
| | - Dora Rolo
- 1 Barcelona Institute for Global Health (ISGlobal) Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Sara Marti
- 4 Microbiology Department, Hospital Universitari Bellvitge, Barcelona, Spain.,5 Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Rafael López-Rojas
- 6 Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Younes Smani
- 6 Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Jerónimo Pachón
- 6 Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville, IBiS, University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Jordi Vila
- 1 Barcelona Institute for Global Health (ISGlobal) Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Jean-Philippe Lavigne
- 2 National Institute of Health and Medical Research, U1047, Montpellier University, Nîmes, France.,3 Department of Microbiology, University Hospital Nîmes, Nîmes, France
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16
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Abstract
The transport of small molecules across membranes is essential for the import of nutrients and other energy sources into the cell and, for the export of waste and other potentially harmful byproducts out of the cell. While hydrophobic molecules are permeable to membranes, ions and other small polar molecules require transport via specialized membrane transport proteins . The two major classes of membrane transport proteins are transporters and channels. With our focus here on porins-major class of non-specific diffusion channel proteins , we will highlight some recent structural biology reports and functional assays that have substantially contributed to our understanding of the mechanism that mediates uptake of small molecules, including antibiotics, across the outer membrane of Enterobacteriaceae . We will also review advances in the regulation of porin expression and porin biogenesis and discuss these pathways as new therapeutic targets.
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Affiliation(s)
- Muriel Masi
- UMR_MD1, Inserm U1261, IRBA, Membranes et Cibles Thérapeutiques, Facultés de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France
| | | | - Jean-Marie Pagès
- UMR_MD1, Inserm U1261, IRBA, Membranes et Cibles Thérapeutiques, Facultés de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France.
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17
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Modulation of antimicrobial resistance in clinical isolates of Enterobacter aerogenes: A strategy combining antibiotics and chemosensitisers. J Glob Antimicrob Resist 2018; 16:187-198. [PMID: 30321623 DOI: 10.1016/j.jgar.2018.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 10/05/2018] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE The main focus of this study was to evaluate the antimicrobial susceptibility profiles of a number of human clinical isolates of Enterobacter aerogenes isolates and to explore the effects of selected chemosensitisers on reversal of the resistant phenotype of these isolates. METHODS This study design was accomplished by: (i) characterising several multidrug-resistant (MDR) E. aerogenes clinical isolates; (ii) evaluating the contribution of target gene mutations to the resistance phenotype, focusing on fluoroquinolones and chloramphenicol only; (iii) evaluating the contribution of membrane permeability and efflux to the MDR phenotype; (iv) assessing the combined action of selected antimicrobials and chemosensitisers in order to identify combinations with synergistic effects able to reduce the minimum inhibitory concentration (MIC); and (v) understanding how these combinations can modulate the permeability or efflux of these isolates. RESULTS Resistance to ciprofloxacin could not be totally reversed owing to pre-existing mutations in target genes. Chloramphenicol susceptibility was efficiently restored by the addition of the selected chemosensitisers. From the modulation kinetics it was clear that phenothiazines were able to increase the accumulation of Hoechst dye. CONCLUSIONS Modulation of permeability and efflux in the presence of chemosensitisers can help us to propose more appropriate chemotherapeutic combinations that can set the model to be used in the treatment of these and other MDR infections.
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18
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Guo X, Wang M, Wang L, Wang Y, Chen T, Wu P, Chen M, Liu B, Feng L. Establishment of a Molecular Serotyping Scheme and a Multiplexed Luminex-Based Array for Enterobacter aerogenes. Front Microbiol 2018; 9:501. [PMID: 29616012 PMCID: PMC5867348 DOI: 10.3389/fmicb.2018.00501] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/05/2018] [Indexed: 11/17/2022] Open
Abstract
Serotyping based on surface polysaccharide antigens is important for the clinical detection and epidemiological surveillance of pathogens. Polysaccharide gene clusters (PSgcs) are typically responsible for the diversity of bacterial surface polysaccharides. Through whole-genome sequencing and analysis, eight putative PSgc types were identified in 23 Enterobacter aerogenes strains from several geographic areas, allowing us to present the first molecular serotyping system for E. aerogenes. A conventional antigenic scheme was also established and correlated well with the molecular serotyping system that was based on PSgc genetic variation, indicating that PSgc-based molecular typing and immunological serology provide equally valid results. Further, a multiplex Luminex-based array was developed, and a double-blind test was conducted with 97 clinical specimens from Shanghai, China, to validate our array. The results of these analyses indicated that strains containing PSgc4 and PSgc7 comprised the predominant groups. We then examined 86 publicly available E. aerogenes strain genomes and identified an additional seven novel PSgc types, with PSgc10 being the most abundant type. In total, our study identified 15 PSgc types in E. aerogenes, providing the basis for a molecular serotyping scheme. From these results, differing epidemic patterns were identified between strains that were predominant in different regions. Our study highlights the feasibility and reliability of a serotyping system based on PSgc diversity, and for the first time, presents a molecular serotyping system, as well as an antigenic scheme for E. aerogenes, providing the basis for molecular diagnostics and epidemiological surveillance of this important emerging pathogen.
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Affiliation(s)
- Xi Guo
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education-Tianjin Economic-Technological Development Area, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Nankai University-Tianjin Economic-Technological Development Area, Tianjin, China
| | - Min Wang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education-Tianjin Economic-Technological Development Area, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Nankai University-Tianjin Economic-Technological Development Area, Tianjin, China
| | - Lu Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University-Tianjin Economic-Technological Development Area, Tianjin, China
| | - Yao Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University-Tianjin Economic-Technological Development Area, Tianjin, China
| | - Tingting Chen
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University-Tianjin Economic-Technological Development Area, Tianjin, China
| | - Pan Wu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University-Tianjin Economic-Technological Development Area, Tianjin, China
| | - Min Chen
- Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China
| | - Bin Liu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education-Tianjin Economic-Technological Development Area, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Nankai University-Tianjin Economic-Technological Development Area, Tianjin, China
| | - Lu Feng
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education-Tianjin Economic-Technological Development Area, Tianjin, China.,Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Economic-Technological Development Area, Tianjin, China.,TEDA Institute of Biological Sciences and Biotechnology, Nankai University-Tianjin Economic-Technological Development Area, Tianjin, China
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19
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Hornsey M, Wareham DW. Effects of In vivo Emergent Tigecycline Resistance on the Pathogenic Potential of Acinetobacter baumannii. Sci Rep 2018. [PMID: 29523824 PMCID: PMC5844891 DOI: 10.1038/s41598-018-22549-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Multidrug-resistant lineages of Acinetobacter baumannii (MDRAB) are important nosocomial pathogens. As tigecycline remains active against most MDRAB we sought to investigate whether tigecycline resistance impacts biological fitness. The effects of treatment-emergent tigecycline resistance were investigated in vitro and in vivo using two pre- (AB210; W6976) and post-therapy (AB211; W7282) clinical pairs, recovered from individual patients, where tigecycline resistance was associated with up-regulated efflux activity. All isolates belonged to the same epidemic UK lineage. Significant differences were observed in end-point survival proportions between AB210 and AB211, but not between W6976 and W7282, using the Galleria mellonella infection model. Isolate AB211 outcompeted AB210 in vivo, in contrast to isolate W7282, which was outcompeted by its pre-therapy counterpart, W6972. Whole-genome sequencing of isolates W6976 and W7282 revealed a mutation in the adeABC regulatory gene, adeS in W7282; resulting in a Ser-8 → Arg substitution. Previous whole-genome comparison of AB210 and AB211 also identified a non-synonymous mutation in adeS, among several other lesions in genes involved in biofilm formation and DNA mismatch repair; consistent with the phenotypic differences described here. In conclusion, the differing effects on the wider phenotype were not predictable from the antibiograms or clonal lineage, despite a common mechanism of tigecycline resistance.
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Affiliation(s)
- Michael Hornsey
- Antimicrobial Research Group, Centre for Immunology and Infectious Disease, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University London, London, UK
| | - David W Wareham
- Antimicrobial Research Group, Centre for Immunology and Infectious Disease, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University London, London, UK. .,Division of Infection, Barts & The London NHS Trust, London, UK.
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20
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Molitor A, James CE, Fanning S, Pagès JM, Davin-Regli A. Ram locus is a key regulator to trigger multidrug resistance in Enterobacter aerogenes. J Med Microbiol 2018; 67:148-159. [PMID: 29297851 DOI: 10.1099/jmm.0.000667] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Several genetic regulators belonging to AraC family are involved in the emergence of MDR isolates of E. aerogenes due to alterations in membrane permeability. Compared with the genetic regulator Mar, RamA may be more relevant towards the emergence of antibiotic resistance. METHODOLOGY Focusing on the global regulators, Mar and Ram, we compared the amino acid sequences of the Ram repressor in 59 clinical isolates and laboratory strains of E. aerogenes. Sequence types were associated with their corresponding multi-drug resistance phenotypes and membrane protein expression profiles using MIC and immunoblot assays. Quantitative gene expression analysis of the different regulators and their targets (porins and efflux pump components) were performed. RESULTS In the majority of the MDR isolates tested, ramR and a region upstream of ramA were mutated but marR or marA were unchanged. Expression and cloning experiments highlighted the involvement of the ram locus in the modification of membrane permeability. Overexpression of RamA lead to decreased porin production and increased expression of efflux pump components, whereas overexpression of RamR had the opposite effects. CONCLUSION Mutations or deletions in ramR, leading to the overexpression of RamA predominated in clinical MDR E. aerogenes isolates and were associated with a higher-level of expression of efflux pump components. It was hypothesised that mutations in ramR, and the self-regulating region proximal to ramA, probably altered the binding properties of the RamR repressor; thereby producing the MDR phenotype. Consequently, mutability of RamR may play a key role in predisposing E. aerogenes towards the emergence of a MDR phenotype.
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Affiliation(s)
- Alexander Molitor
- UMR_MD1, Facultés de Pharmacie and Médecine, Aix-Marseille Univ, Marseille, France
| | - Chloë E James
- Biomedical Research Centre and Ecosystems and Environment Research Centre, School of Environment and Life Sciences, University of Salford, Salford, M5 4WT, UK
| | - Séamus Fanning
- School of Public Health, Physiotherapy and Sports Science, UCD-Centre For Food Safety, University College Dublin, Belfield, Dublin D4 N2E5, Ireland
| | - Jean-Marie Pagès
- UMR_MD1, Facultés de Pharmacie and Médecine, Aix-Marseille Univ, Marseille, France
| | - Anne Davin-Regli
- UMR_MD1, Facultés de Pharmacie and Médecine, Aix-Marseille Univ, Marseille, France
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21
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Raphael E, Riley LW. Infections Caused by Antimicrobial Drug-Resistant Saprophytic Gram-Negative Bacteria in the Environment. Front Med (Lausanne) 2017; 4:183. [PMID: 29164118 PMCID: PMC5670356 DOI: 10.3389/fmed.2017.00183] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 10/12/2017] [Indexed: 11/25/2022] Open
Abstract
Background Drug-resistance genes found in human bacterial pathogens are increasingly recognized in saprophytic Gram-negative bacteria (GNB) from environmental sources. The clinical implication of such environmental GNBs is unknown. Objectives We conducted a systematic review to determine how often such saprophytic GNBs cause human infections. Methods We queried PubMed for articles published in English, Spanish, and French between January 2006 and July 2014 for 20 common environmental saprophytic GNB species, using search terms “infections,” “human infections,” “hospital infection.” We analyzed 251 of 1,275 non-duplicate publications that satisfied our selection criteria. Saprophytes implicated in blood stream infection (BSI), urinary tract infection (UTI), skin and soft tissue infection (SSTI), post-surgical infection (PSI), osteomyelitis (Osteo), and pneumonia (PNA) were quantitatively assessed. Results Thirteen of the 20 queried GNB saprophytic species were implicated in 674 distinct infection episodes from 45 countries. The most common species included Enterobacter aerogenes, Pantoea agglomerans, and Pseudomonas putida. Of these infections, 443 (66%) had BSI, 48 (7%) had SSTI, 36 (5%) had UTI, 28 (4%) had PSI, 21 (3%) had PNA, 16 (3%) had Osteo, and 82 (12%) had other infections. Nearly all infections occurred in subjects with comorbidities. Resistant strains harbored extended-spectrum beta-lactamase (ESBL), carbapenemase, and metallo-β-lactamase genes recognized in human pathogens. Conclusion These observations show that saprophytic GNB organisms that harbor recognized drug-resistance genes cause a wide spectrum of infections, especially as opportunistic pathogens. Such GNB saprophytes may become increasingly more common in healthcare settings, as has already been observed with other environmental GNBs such as Acinetobacter baumannii and Pseudomonas aeruginosa.
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Affiliation(s)
- Eva Raphael
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Lee W Riley
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
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22
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Rosa JF, Rizek C, Marchi AP, Guimaraes T, Miranda L, Carrilho C, Levin AS, Costa SF. Clonality, outer-membrane proteins profile and efflux pump in KPC- producing Enterobacter sp. in Brazil. BMC Microbiol 2017; 17:69. [PMID: 28302074 PMCID: PMC5356252 DOI: 10.1186/s12866-017-0970-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 03/04/2017] [Indexed: 11/21/2022] Open
Abstract
Background Carbapenems resistance in Enterobacter spp. has increased in the last decade, few studies, however, described the mechanisms of resistance in this bacterium. This study evaluated clonality and mechanisms of carbapenems resistance in clinical isolates of Enterobacter spp. identified in three hospitals in Brazil (Hospital A, B and C) over 7-year. Methods Antibiotics sensitivity, pulsed-field gel electrophoresis (PFGE), PCR for carbapenemase and efflux pump genes were performed for all carbapenems-resistant isolates. Outer-membrane protein (OMP) was evaluated based on PFGE profile. Results A total of 130 isolates of Enterobacter spp were analyzed, 44/105 (41, 9%) E. aerogenes and 8/25 (32,0%) E. cloacae were resistant to carbapenems. All isolates were susceptible to fosfomycin, polymyxin B and tigecycline. KPC was present in 88.6% of E. aerogenes and in all E. cloacae resistant to carbapenems. The carbapenems-resistant E. aerogenes identified in hospital A belonged to six clones, however, a predominant clone was identified in this hospital over the study period. There is a predominant clone in Hospital B and Hospital C as well. The mechanisms of resistance to carbapenems differ among subtypes. Most of the isolates co-harbored blaKPC, blaTEM and /or blaCTX associated with decreased or lost of 35–36KDa and or 39 KDa OMP. The efflux pump AcrAB-TolC gene was only identified in carbapenems-resistant E. cloacae. Conclusions There was a predominant clone in each hospital suggesting that cross-transmission of carbapenems-resistant Enterobacter spp. was frequent. The isolates presented multiple mechanisms of resistance to carbapenems including OMP alteration.
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Affiliation(s)
- Juliana Ferraz Rosa
- Department of Infectious Diseases, University of São Paulo, Laboratory of Medical Investigation 54 (LIM-54), Hospital Das Clínicas FMUSP, São Paulo, Brazil
| | - Camila Rizek
- Department of Infectious Diseases, University of São Paulo, Laboratory of Medical Investigation 54 (LIM-54), Hospital Das Clínicas FMUSP, São Paulo, Brazil
| | - Ana Paula Marchi
- Department of Infectious Diseases, University of São Paulo, Laboratory of Medical Investigation 54 (LIM-54), Hospital Das Clínicas FMUSP, São Paulo, Brazil
| | - Thais Guimaraes
- Department of Infectious Diseases, University of São Paulo, Laboratory of Medical Investigation 54 (LIM-54), Hospital Das Clínicas FMUSP, São Paulo, Brazil
| | - Lourdes Miranda
- Hospital de Itapecerica da Serra, Itapecerica da Serra, SP, Brazil
| | | | - Anna S Levin
- Department of Infectious Diseases, University of São Paulo, Laboratory of Medical Investigation 54 (LIM-54), Hospital Das Clínicas FMUSP, São Paulo, Brazil
| | - Silvia F Costa
- LIM-54, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
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Majewski P, Wieczorek P, Ojdana D, Sieńko A, Kowalczuk O, Sacha P, Nikliński J, Tryniszewska E. Altered Outer Membrane Transcriptome Balance with AmpC Overexpression in Carbapenem-Resistant Enterobacter cloacae. Front Microbiol 2016; 7:2054. [PMID: 28066375 PMCID: PMC5179509 DOI: 10.3389/fmicb.2016.02054] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/07/2016] [Indexed: 11/13/2022] Open
Abstract
The growing incidence of multidrug-resistant (MDR) bacteria is an emerging challenge in modern medicine. The utility of carbapenems, considered “last-line” agents in therapy of infections caused by MDR pathogens, is being diminished by the growing incidence of various resistance mechanisms. Enterobacter cloacae have lately begun to emerge as an important pathogen prone to exhibiting multiple drug resistance. We aimed to investigate the molecular basis of carbapenem-resistance in 44 E. cloacae clinical strains resistant to at least one carbapenem, and 21 susceptible strains. Molecular investigation of 65 E. cloacae clinical strains was based on quantitative polymerase chain reaction (qPCR) allowing for amplification of ampC, ompF, and ompC transcripts, and analysis of nucleotide sequences of alleles included in MLST scheme. Co-operation of three distinct carbapenem resistance mechanisms has been reported—production of OXA-48 (5%), AmpC overproduction (97.7%), and alterations in outer membrane (OM) transcriptome balance. Carbapenem-resistant E. cloacae were characterized by (1.) downregulation of ompF gene (53.4%), which encodes protein with extensive transmembrane channels, and (2.) the polarization of OM transcriptome-balance (79.1%), which was sloped toward ompC gene, encoding proteins recently reported to possess restrictive transmembrane channels. Subpopulations of carbapenem-susceptible strains showed relatively high degrees of sequence diversity without predominant types. ST-89 clearly dominates among carbapenem-resistant strains (88.6%) suggesting clonal spread of resistant strains. The growing prevalence of pathogens resistant to all currently available antimicrobial agents heralds the potential risk of a future “post-antibiotic era.” Great efforts need to be taken to explore the background of resistance to “last resort” antimicrobials.
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Affiliation(s)
- Piotr Majewski
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok Bialystok, Poland
| | - Piotr Wieczorek
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok Bialystok, Poland
| | - Dominika Ojdana
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok Bialystok, Poland
| | - Anna Sieńko
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok Bialystok, Poland
| | - Oksana Kowalczuk
- Department of Clinical Molecular Biology, Medical University of Bialystok Bialystok, Poland
| | - Paweł Sacha
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok Bialystok, Poland
| | - Jacek Nikliński
- Department of Clinical Molecular Biology, Medical University of Bialystok Bialystok, Poland
| | - Elżbieta Tryniszewska
- Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok Bialystok, Poland
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Grazziotin AL, Vidal NM, Palmeiro JK, Dalla-Costa LM, Venancio TM. Genome Sequencing of Four Multidrug-Resistant Enterobacter aerogenes Isolates from Hospitalized Patients in Brazil. Front Microbiol 2016; 7:1649. [PMID: 27833588 PMCID: PMC5081556 DOI: 10.3389/fmicb.2016.01649] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 10/04/2016] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ana Laura Grazziotin
- Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy RibeiroCampos dos Goytacazes, Brazil
| | - Newton M. Vidal
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesda, MD, USA
| | - Jussara K. Palmeiro
- Laboratório de Bacteriologia, Unidade Laboratório de Análises Clínicas, Hospital de Clínicas, Universidade Federal do ParanáCuritiba, Brazil
- Faculdades e Instituto de Pesquisa Pelé Pequeno PríncipeCuritiba, Brazil
| | - Libera Maria Dalla-Costa
- Laboratório de Bacteriologia, Unidade Laboratório de Análises Clínicas, Hospital de Clínicas, Universidade Federal do ParanáCuritiba, Brazil
- Faculdades e Instituto de Pesquisa Pelé Pequeno PríncipeCuritiba, Brazil
| | - Thiago M. Venancio
- Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy RibeiroCampos dos Goytacazes, Brazil
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Abstract
UNLABELLED The outer membrane (OM) of Gram-negative bacteria provides protection against toxic molecules, including reactive oxygen species (ROS). Decreased OM permeability can promote bacterial survival under harsh circumstances and protects against antibiotics. To better understand the regulation of OM permeability, we studied the real-time influx of hydrogen peroxide in Salmonella bacteria and discovered two novel mechanisms by which they rapidly control OM permeability. We found that pores in two major OM proteins, OmpA and OmpC, could be rapidly opened or closed when oxidative stress is encountered and that the underlying mechanisms rely on the formation of disulfide bonds in the periplasmic domain of OmpA and TrxA, respectively. Additionally, we found that a Salmonella mutant showing increased OM permeability was killed more effectively by treatment with antibiotics. Together, these results demonstrate that Gram-negative bacteria regulate the influx of ROS for defense against oxidative stress and reveal novel targets that can be therapeutically targeted to increase bacterial killing by conventional antibiotics. IMPORTANCE Pathogenic bacteria have evolved ways to circumvent inflammatory immune responses. A decrease in bacterial outer membrane permeability during infection helps protect bacteria from toxic molecules produced by the host immune system and allows for effective colonization of the host. In this report, we reveal molecular mechanisms that rapidly alter outer membrane pores and their permeability in response to hydrogen peroxide and oxidative stress. These mechanisms are the first examples of pores that are rapidly opened or closed in response to reactive oxygen species. Moreover, one of these mechanisms can be targeted to artificially increase membrane permeability and thereby increase bacterial killing by the antibiotic cefotaxime during in vitro experiments and in a mouse model of infection. We envision that a better understanding of the regulation of membrane permeability will lead to new targets and treatment options for multidrug-resistant infections.
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Aelenei P, Miron A, Trifan A, Bujor A, Gille E, Aprotosoaie AC. Essential Oils and Their Components as Modulators of Antibiotic Activity against Gram-Negative Bacteria. MEDICINES 2016; 3:medicines3030019. [PMID: 28930130 PMCID: PMC5456245 DOI: 10.3390/medicines3030019] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 07/17/2016] [Accepted: 07/18/2016] [Indexed: 12/21/2022]
Abstract
Gram-negative bacteria cause infections that are difficult to treat due to the emergence of multidrug resistance. This review summarizes the current status of the studies investigating the capacity of essential oils and their components to modulate antibiotic activity against Gram-negative bacteria. Synergistic interactions are particularly discussed with reference to possible mechanisms by which essential oil constituents interact with antibiotics. Special emphasis is given to essential oils and volatile compounds that inhibit efflux pumps, thus reversing drug resistance in Gram-negative bacteria. In addition, indifference and antagonism between essential oils/volatile compounds and conventional antibiotics have also been reported. Overall, this literature review reveals that essential oils and their purified components enhance the efficacy of antibiotics against Gram-negative bacteria, being promising candidates for the development of new effective formulations against Gram-negative bacteria.
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Affiliation(s)
- Petruta Aelenei
- Department of Pharmacognosy, Faculty of Pharmacy, University of Medicine and Pharmacy Grigore T. Popa-Iasi, Universitatii 16, Iasi 700115, Romania.
- Regulatory Affairs Department, Fiterman Pharma LLC, Pacurari Road 127, Iasi 700544, Romania.
| | - Anca Miron
- Department of Pharmacognosy, Faculty of Pharmacy, University of Medicine and Pharmacy Grigore T. Popa-Iasi, Universitatii 16, Iasi 700115, Romania.
| | - Adriana Trifan
- Department of Pharmacognosy, Faculty of Pharmacy, University of Medicine and Pharmacy Grigore T. Popa-Iasi, Universitatii 16, Iasi 700115, Romania.
| | - Alexandra Bujor
- Department of Pharmacognosy, Faculty of Pharmacy, University of Medicine and Pharmacy Grigore T. Popa-Iasi, Universitatii 16, Iasi 700115, Romania.
| | - Elvira Gille
- Stejarul Biological Research Centre/National Institute of Research and Development for Biological Sciences, Alexandru cel Bun 6, Piatra Neamt 610004, Romania.
| | - Ana Clara Aprotosoaie
- Department of Pharmacognosy, Faculty of Pharmacy, University of Medicine and Pharmacy Grigore T. Popa-Iasi, Universitatii 16, Iasi 700115, Romania.
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Modulation of Membrane Influx and Efflux in Escherichia coli Sequence Type 131 Has an Impact on Bacterial Motility, Biofilm Formation, and Virulence in a Caenorhabditis elegans Model. Antimicrob Agents Chemother 2016; 60:2901-11. [PMID: 26926643 DOI: 10.1128/aac.02872-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/21/2016] [Indexed: 12/17/2022] Open
Abstract
Energy-dependent efflux overexpression and altered outer membrane permeability (influx) can promote multidrug resistance (MDR). The present study clarifies the regulatory pathways that control membrane permeability in the pandemic clone Escherichia coli sequence type 131 (ST131) and evaluates the impact of efflux and influx modulations on biofilm formation, motility, and virulence in the Caenorhabditis elegans model. Mutants of two uropathogenic E. coli (UPEC) strains, MECB5 (ST131; H30-Rx) and CFT073 (ST73), as well as a fecal strain, S250 (ST131; H22), were in vitro selected using continuous subculture in subinhibitory concentrations of ertapenem (ETP), chloramphenicol (CMP), and cefoxitin (FOX). Mutations in genes known to control permeability were shown for the two UPEC strains: MECB5-FOX (deletion of 127 bp in marR; deletion of 1 bp and insertion of an IS1 element in acrR) and CFT073-CMP (a 1-bp deletion causing a premature stop in marR). We also demonstrated that efflux phenotypes in the mutants selected with CMP and FOX were related to the AcrAB-TolC pump, but also to other efflux systems. Alteration of membrane permeability, caused by underexpression of the two major porins, OmpF and OmpC, was shown in MECB5-ETP and mutants selected with FOX. Lastly, our findings suggest that efflux pump-overproducing isolates (CMP mutants) pose a serious threat in terms of virulence (significant reduction in worm median survival) and host colonization. Lack of porins (ETP and FOX mutants) led to a high level of antibiotic resistance in an H30-Rx subclone. Nevertheless, this adaptation created a physiological disadvantage (decreased motility and ability to form biofilm) associated with a low potential for virulence.
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Mutters NT, Zimmermann S, Kaase M, Mischnik A. Activity of temocillin, mecillinam, ceftazidime, and ceftazidime/avibactam against carbapenem-non-susceptible Enterobacteriaceae without carbapenemase production. Eur J Clin Microbiol Infect Dis 2015; 34:2429-37. [PMID: 26433746 DOI: 10.1007/s10096-015-2498-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 09/21/2015] [Indexed: 12/31/2022]
Abstract
Treatment options for multidrug-resistant Gram-negative infections are scarce and therefore alternatives with a narrow spectrum or new agents are sought. Antimicrobial susceptibility to temocillin, mecillinam, ceftazidime, and ceftazidime/avibactam was determined using Etest and disk diffusion according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) methodology. A total of 77 carbapenem-nonsusceptible Enterobacteriaceae were studied, including Klebsiella pneumoniae (26%), Escherichia coli (26%), Enterobacter cloacae (26%), and Enterobacter aerogenes (22%). Several phenotypic tests, PCRs followed by sequencing and a microbiological bioassay excluded carbapenemase production in all isolates. Antimicrobial susceptibility rates were low for temocillin (15.6%, minimum inhibitory concentration [MIC] range 2 to >1,024 μg/ml), moderate for mecillinam (59.7%, MIC range 0.25 to >256 μg/ml), and excellent for ceftazidime/avibactam (100%, zone diameter range 19 to 32 mm, median 25 mm). 5.2% of the isolates were susceptible to ceftazidime alone (zone diameter range 6 to 32 mm). In this study, mecillinam exhibited moderate and ceftazidime/avibactam excellent in vitro antimicrobial activity against carbapenem-nonsusceptible Enterobacteriaceae without carbapenemase production. Ceftazidime/avibactam was able to restore previously reduced susceptibility to ceftazidime in all isolates, thus potentiating its activity. Temocillin only exhibited low in vitro antimicrobial activity against the isolates. Further evaluation of mecillinam and ceftazidime/avibactam with regard to the potential clinical utility against infections caused by these pathogens has to be performed.
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Affiliation(s)
- N T Mutters
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - S Zimmermann
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany
| | - M Kaase
- National Reference Laboratory for Multidrug-Resistant Gram-Negative Bacteria, Department of Medical Microbiology, Ruhr University Bochum, 44801, Bochum, Germany
| | - A Mischnik
- Department of Infectious Diseases, Medical Microbiology and Hygiene, Heidelberg University Hospital, 69120, Heidelberg, Germany. .,Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Strasse 55, 79106, Freiburg, Germany.
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29
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In Vivo Evolution of Bacterial Resistance in Two Cases of Enterobacter aerogenes Infections during Treatment with Imipenem. PLoS One 2015; 10:e0138828. [PMID: 26398358 PMCID: PMC4580588 DOI: 10.1371/journal.pone.0138828] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/03/2015] [Indexed: 11/24/2022] Open
Abstract
Infections caused by multidrug resistant (MDR) bacteria are a major concern worldwide. Changes in membrane permeability, including decreased influx and/or increased efflux of antibiotics, are known as key contributors of bacterial MDR. Therefore, it is of critical importance to understand molecular mechanisms that link membrane permeability to MDR in order to design new antimicrobial strategies. In this work, we describe genotype-phenotype correlations in Enterobacter aerogenes, a clinically problematic and antibiotic resistant bacterium. To do this, series of clinical isolates have been periodically collected from two patients during chemotherapy with imipenem. The isolates exhibited different levels of resistance towards multiple classes of antibiotics, consistently with the presence or the absence of porins and efflux pumps. Transport assays were used to characterize membrane permeability defects. Simultaneous genome-wide analysis allowed the identification of putative mutations responsible for MDR. The genome of the imipenem-susceptible isolate G7 was sequenced to closure and used as a reference for comparative genomics. This approach uncovered several loci that were specifically mutated in MDR isolates and whose products are known to control membrane permeability. These were omp35 and omp36, encoding the two major porins; rob, encoding a global AraC-type transcriptional activator; cpxA, phoQ and pmrB, encoding sensor kinases of the CpxRA, PhoPQ and PmrAB two-component regulatory systems, respectively. This report provides a comprehensive analysis of membrane alterations relative to mutational steps in the evolution of MDR of a recognized nosocomial pathogen.
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30
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Davin-Regli A, Pagès JM. Enterobacter aerogenes and Enterobacter cloacae; versatile bacterial pathogens confronting antibiotic treatment. Front Microbiol 2015; 6:392. [PMID: 26042091 PMCID: PMC4435039 DOI: 10.3389/fmicb.2015.00392] [Citation(s) in RCA: 292] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 04/16/2015] [Indexed: 12/14/2022] Open
Abstract
Enterobacter aerogenes and E. cloacae have been reported as important opportunistic and multiresistant bacterial pathogens for humans during the last three decades in hospital wards. These Gram-negative bacteria have been largely described during several outbreaks of hospital-acquired infections in Europe and particularly in France. The dissemination of Enterobacter sp. is associated with the presence of redundant regulatory cascades that efficiently control the membrane permeability ensuring the bacterial protection and the expression of detoxifying enzymes involved in antibiotic degradation/inactivation. In addition, these bacterial species are able to acquire numerous genetic mobile elements that strongly contribute to antibiotic resistance. Moreover, this particular fitness help them to colonize several environments and hosts and rapidly and efficiently adapt their metabolism and physiology to external conditions and environmental stresses. Enterobacter is a versatile bacterium able to promptly respond to the antibiotic treatment in the colonized patient. The balance of the prevalence, E. aerogenes versus E. cloacae, in the reported hospital infections during the last period, questions about the horizontal transmission of mobile elements containing antibiotic resistance genes, e.g., the efficacy of the exchange of resistance genes Klebsiella pneumoniae to Enterobacter sp. It is also important to mention the possible role of antibiotic use in the treatment of bacterial infectious diseases in this E. aerogenes/E. cloacae evolution.
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Affiliation(s)
- Anne Davin-Regli
- Transporteurs Membranaires, Chimiorésistance et Drug Design, Facultés de Médecine et Pharmacie, UMR-MD1, IRBA - Aix-Marseille Université, Marseille France
| | - Jean-Marie Pagès
- Transporteurs Membranaires, Chimiorésistance et Drug Design, Facultés de Médecine et Pharmacie, UMR-MD1, IRBA - Aix-Marseille Université, Marseille France
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31
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Wang Q, Mao D, Mu Q, Luo Y. Enhanced horizontal transfer of antibiotic resistance genes in freshwater microcosms induced by an ionic liquid. PLoS One 2015; 10:e0126784. [PMID: 25951456 PMCID: PMC4423773 DOI: 10.1371/journal.pone.0126784] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 04/07/2015] [Indexed: 12/22/2022] Open
Abstract
The spread and propagation of antibiotic resistance genes (ARGs) is a worldwide public health concern. Ionic liquids (ILs), considered as "environmentally friendly" replacements for industrial organic solvents, have been widely applied in modern industry. However, few data have been collected regarding the potential ecological and environmental risks of ILs, which are important for preparing for their potential discharge into the environment. In this paper, the IL 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]) (0.001-5.0 g/L) was tested for its effects on facilitating ARGs horizontal transfer mediated by plasmid RP4 in freshwater microcosms. In the horizontal transfer microcosms, the transfer frequency of plasmid RP4 was significantly enhanced (60-fold higher than untreated groups) by the IL [BMIm][PF6] (1.0 g/L). Meanwhile, two strains of opportunistic pathogen Acinetobacter spp. and Salmonella spp. were isolated among the transconjugants, illustrating plasmid RP4 mediated horizontal transfer of ARGs occurred in pathogen. This could increase the risk of ARGs dissemination to human pathogens and pose great threat to public health. The cause that [BMIm[PF6] enhanced the transfer frequency of plasmid RP4 was proposed by suppressed cell membrane barrier and enhanced cell membrane permeability, which was evidenced by flow cytometry (FCM). This is the first report that some ILs facilitate horizontal transfer of plasmid RP4 which is widely distributed in the environment and thus add the adverse effects of the environmental risk of ILs.
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Affiliation(s)
- Qing Wang
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Daqing Mao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Quanhua Mu
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Yi Luo
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
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32
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Chen Z, Li H, Feng J, Li Y, Chen X, Guo X, Chen W, Wang L, Lin L, Yang H, Yang W, Wang J, Zhou D, Liu C, Yin Z. NDM-1 encoded by a pNDM-BJ01-like plasmid p3SP-NDM in clinical Enterobacter aerogenes. Front Microbiol 2015; 6:294. [PMID: 25926823 PMCID: PMC4396501 DOI: 10.3389/fmicb.2015.00294] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/25/2015] [Indexed: 11/13/2022] Open
Abstract
A carbapenem-nonsusceptible Enterobacter aerogenes strain named 3-SP was isolated from a human case of pneumonia in a Chinese teaching hospital. NDM-1 carbapenemase is produced by a pNDM-BJ01-like conjugative plasmid designated p3SP-NDM to account for carbapenem resistance of 3-SP. p3SP-NDM was fully sequenced and compared with all publically available pNDM-BJ01-like plasmids. The genetic differences between p3SP-NDM and pNDM-BJ01 include only 18 single nucleotide polymorphisms, a 1 bp deletion and a 706 bp deletion. p3SP-NDM and pNDM-BJ01 harbor an identical Tn125 element organized as ISAba125, blaNDM−1, bleMBL, ΔtrpF, dsbC, cutA, ΔgroES, groEL, ISCR27, and ISAba125. The blaNDM−1 surrounding regions in these pNDM-BJ01-like plasmids have a conserved linear organization ISAba14-aphA6-Tn125-unknown IS, with considerable genetic differences identified within or immediately downstream of Tn125. All reported pNDM-BJ01-like plasmids are exclusively found in Acinetobacter, whereas this is the first report of identification of a pNDM-BJ01-like plasmid in Enterobacteriaceae.
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Affiliation(s)
- Zhenhong Chen
- Nanlou Respiratory Diseases Department, Chinese People's Liberation Army General Hospital Beijing, China
| | - Hongxia Li
- Nanlou Respiratory Diseases Department, Chinese People's Liberation Army General Hospital Beijing, China
| | - Jiao Feng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Yuxue Li
- The First Hospital of Shijiazhuang City Shijiazhuang, China
| | - Xin Chen
- Zhongshan School of Medicine, Sun Yat-Sen University Guangzhou, China
| | - Xuemin Guo
- Zhongshan School of Medicine, Sun Yat-Sen University Guangzhou, China
| | - Weijun Chen
- Beijing Institute of Genomics, Chinese Academy of Sciences Beijing, China
| | - Li Wang
- Nanlou Respiratory Diseases Department, Chinese People's Liberation Army General Hospital Beijing, China
| | - Lei Lin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Huiying Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Wenhui Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Jie Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Changting Liu
- Nanlou Respiratory Diseases Department, Chinese People's Liberation Army General Hospital Beijing, China
| | - Zhe Yin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
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33
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Weichbrodt C, Bajaj H, Baaken G, Wang J, Guinot S, Kreir M, Behrends JC, Winterhalter M, Fertig N. Antibiotic translocation through porins studied in planar lipid bilayers using parallel platforms. Analyst 2015; 140:4874-81. [DOI: 10.1039/c4an02335h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A comparative study of three different techniques Orbit16, Port-a-Patch and BLM applied for the investigation of antibiotic translocation.
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Affiliation(s)
| | | | | | - Jiajun Wang
- Nanion Technologies GmbH
- 80 636 Munich
- Germany
- Jacobs University Bremen
- 28 759 Bremen
| | | | | | - Jan C. Behrends
- Ionera Technologies GmbH
- 79104 Freiburg
- Germany
- Laboratory for Membrane Physiology and Technology
- Department of Physiology
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34
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In vitro and in vivo activities of tigecycline-colistin combination therapies against carbapenem-resistant Enterobacteriaceae. Antimicrob Agents Chemother 2014; 58:3541-6. [PMID: 24687491 DOI: 10.1128/aac.02449-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We assessed the activity of tigecycline (TGC) combined with colistin (COL) against carbapenem-resistant enterobacteria. Synergy occurred in vitro against the majority of isolates, with the exception of Serratia marcescens. In a simple animal model (Galleria mellonella), TGC-COL was superior (P < 0.01) in treating Escherichia coli, Klebsiella pneumoniae, and Enterobacter infections, including those with TGC-COL resistance. Clinical studies are needed to determine whether TGC-COL regimens may be a viable option.
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35
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Beceiro A, Tomás M, Bou G. Antimicrobial resistance and virulence: a successful or deleterious association in the bacterial world? Clin Microbiol Rev 2013; 26:185-230. [PMID: 23554414 PMCID: PMC3623377 DOI: 10.1128/cmr.00059-12] [Citation(s) in RCA: 602] [Impact Index Per Article: 54.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hosts and bacteria have coevolved over millions of years, during which pathogenic bacteria have modified their virulence mechanisms to adapt to host defense systems. Although the spread of pathogens has been hindered by the discovery and widespread use of antimicrobial agents, antimicrobial resistance has increased globally. The emergence of resistant bacteria has accelerated in recent years, mainly as a result of increased selective pressure. However, although antimicrobial resistance and bacterial virulence have developed on different timescales, they share some common characteristics. This review considers how bacterial virulence and fitness are affected by antibiotic resistance and also how the relationship between virulence and resistance is affected by different genetic mechanisms (e.g., coselection and compensatory mutations) and by the most prevalent global responses. The interplay between these factors and the associated biological costs depend on four main factors: the bacterial species involved, virulence and resistance mechanisms, the ecological niche, and the host. The development of new strategies involving new antimicrobials or nonantimicrobial compounds and of novel diagnostic methods that focus on high-risk clones and rapid tests to detect virulence markers may help to resolve the increasing problem of the association between virulence and resistance, which is becoming more beneficial for pathogenic bacteria.
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36
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Masi M, Pagès JM. Structure, Function and Regulation of Outer Membrane Proteins Involved in Drug Transport in Enterobactericeae: the OmpF/C - TolC Case. Open Microbiol J 2013; 7:22-33. [PMID: 23569467 PMCID: PMC3617542 DOI: 10.2174/1874285801307010022] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 02/01/2013] [Accepted: 02/03/2013] [Indexed: 11/26/2022] Open
Abstract
Antibiotic translocation across membranes of Gram-negative bacteria is a key step for the activity on their specific intracellular targets. Resistant bacteria control their membrane permeability as a first line of defense to protect themselves against external toxic compounds such as antibiotics and biocides. On one hand, resistance to small hydrophilic antibiotics such as ß-lactams and fluoroquinolones frequently results from the « closing » of their way in: the general outer membrane porins. On the other hand, an effective way out for a wide range of antibiotics is provided by TolC-like proteins, which are outer membrane components of multidrug efflux pumps. Accordingly, altered membrane permeability, including porin modifications and/or efflux pumps’ overexpression, is always associated to multidrug resistance (MDR) in a number of clinical isolates. Several recent studies have highlighted our current understanding of porins/TolC structures and functions in Enterobacteriaceae. Here, we review the transport of antibiotics through the OmpF/C general porins and the TolC-like channels with regards to recent data on their structure, function, assembly, regulation and contribution to bacterial resistance. Because MDR strains have evolved global strategies to identify and fight our antibiotic arsenal, it is important to constantly update our global knowledge on antibiotic transport.
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Affiliation(s)
- Muriel Masi
- CNRS-UMR 8619, Institut de Biophysique et de Biochimie Moléculaire et Cellulaire (IBBMC), Université Paris Sud, Orsay, France
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Recent Advances in Multi-Drug Resistance (MDR) Efflux Pump Inhibitors of Gram-Positive Bacteria S. aureus. Antibiotics (Basel) 2013; 2:28-45. [PMID: 27029290 PMCID: PMC4790296 DOI: 10.3390/antibiotics2010028] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 01/29/2013] [Accepted: 01/30/2013] [Indexed: 11/17/2022] Open
Abstract
The paper focuses on recent achievements in the search for new chemical compounds able to inhibit multidrug resistance (MDR) mechanisms in Gram-positive pathogens. An analysis of the results of the search for new efflux pump inhibitors (EPIs) for Gram-positive bacteria, which have been performed over the last decade, indicates that almost all efforts are focused on the NorA (MFS) efflux pump in S. aureus. Considering the chemical structures of the NorA EPIs that have been identified, it can be observed that the most active agents belong to the families of compounds possessing conjugated double bonds, e.g., chalcones, piperine-like compounds, N-cinnamoylphenalkylamides or citral amide derivatives. Indole-, dihydronaphthyl-, 2-chloro-5-bromo-phenyl- or piperidine moieties seem to be profitable for the EPI properties, as well. These results, together with an increasing knowledge about a variety of efflux pumps that are involved in MDR of Gram-positive pathogens underline that further search for new EPIs should pay more attention to develop MDR efflux protein targets, including SMR, MATE, ABC or other members of the MFS family.
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Lavigne JP, Sotto A, Nicolas-Chanoine MH, Bouziges N, Pagès JM, Davin-Regli A. An adaptive response of Enterobacter aerogenes to imipenem: regulation of porin balance in clinical isolates. Int J Antimicrob Agents 2012; 41:130-6. [PMID: 23280442 DOI: 10.1016/j.ijantimicag.2012.10.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 10/21/2012] [Accepted: 10/24/2012] [Indexed: 12/28/2022]
Abstract
Imipenem (IPM) is a carbapenem antibiotic frequently used in severe hospital infections. Several reports have mentioned the emergence of resistant isolates exhibiting membrane modifications. A study was conducted between September 2005 and August 2007 to survey infections due to Enterobacter aerogenes in patients hospitalised in a French university hospital. Resistant E. aerogenes clinical isolates obtained from patients treated with IPM and collected during the 3 months following initiation of treatment were phenotypically and molecularly characterised for β-lactamases, efflux pumps activity and outer membrane proteins. Among the 339 patients infected with E. aerogenes during the study period, 41 isolates (12.1%) were resistant to extended-spectrum cephalosporins and 17 patients (5.0%) were treated with IPM. The isolates from these 17 patients presented TEM-24 and basal efflux expression. Following IPM treatment, an IPM-intermediate-susceptible (IPM-I) isolate emerged in 11 patients and an IPM-resistant (IPM-R) isolate in 6 patients. A change in the porin balance (Omp35/Omp36) was observed in IPM-I isolates exhibiting ertapenem resistance. Finally, a porin deficiency (Omp35 and Omp36 absence) was detected in IPM-R isolates associated with efflux pump expression. This study indicates that the alteration in porin expression, including the shift of porin expression and lack of porins, contribute to the E. aerogenes adaptive response to IPM treatment.
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Affiliation(s)
- Jean-Philippe Lavigne
- UMR-MD1, Aix-Marseille Université, IRBA, Facultés de Médecine et de Pharmacie, Marseille, France
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Nicolas-Chanoine MH. Les entérobactéries productrices de bêta-lactamases à spectre élargi : où sont les dangers ? MEDECINE INTENSIVE REANIMATION 2012. [DOI: 10.1007/s13546-012-0463-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nordmann P, Dortet L, Poirel L. Carbapenem resistance in Enterobacteriaceae: here is the storm! Trends Mol Med 2012; 18:263-72. [PMID: 22480775 DOI: 10.1016/j.molmed.2012.03.003] [Citation(s) in RCA: 678] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/29/2012] [Accepted: 03/08/2012] [Indexed: 12/21/2022]
Abstract
The current worldwide emergence of resistance to the powerful antibiotic carbapenem in Enterobacteriaceae constitutes an important growing public health threat. Sporadic outbreaks or endemic situations with enterobacterial isolates not susceptible to carbapenems are now reported not only in hospital settings but also in the community. Acquired class A (KPC), class B (IMP, VIM, NDM), or class D (OXA-48, OXA-181) carbapenemases, are the most important determinants sustaining resistance to carbapenems. The corresponding genes are mostly plasmid-located and associated with various mobile genetic structures (insertion sequences, integrons, transposons), further enhancing their spread. This review summarizes the current knowledge on carbapenem resistance in Enterobacteriaceae, including activity, distribution, clinical impact, and possible novel antibiotic pathways.
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Affiliation(s)
- Patrice Nordmann
- Service de Bactériologie-Virologie, INSERM U914 Emerging Resistance to Antibiotic, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris Sud, K.-Bicêtre, 94275 Le Kremlin-Bicêtre Cedex, France.
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Nikaido H, Pagès JM. Broad-specificity efflux pumps and their role in multidrug resistance of Gram-negative bacteria. FEMS Microbiol Rev 2011; 36:340-63. [PMID: 21707670 DOI: 10.1111/j.1574-6976.2011.00290.x] [Citation(s) in RCA: 479] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Antibiotic resistance mechanisms reported in Gram-negative bacteria are causing a worldwide health problem. The continuous dissemination of 'multidrug-resistant' (MDR) bacteria drastically reduces the efficacy of our antibiotic 'arsenal' and consequently increases the frequency of therapeutic failure. In MDR bacteria, the overexpression of efflux pumps that expel structurally unrelated drugs contributes to the reduced susceptibility by decreasing the intracellular concentration of antibiotics. During the last decade, several clinical data have indicated an increasing involvement of efflux pumps in the emergence and dissemination of resistant Gram-negative bacteria. It is necessary to clearly define the molecular, functional and genetic bases of the efflux pump in order to understand the translocation of antibiotic molecules through the efflux transporter. The recent investigation on the efflux pump AcrB at its structural and physiological levels, including the identification of drug affinity sites and kinetic parameters for various antibiotics, may pave the way towards the rational development of an improved new generation of antibacterial agents as well as efflux inhibitors in order to efficiently combat efflux-based resistance mechanisms.
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Affiliation(s)
- Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
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