101
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Pang Z, Raudonis R, Glick BR, Lin TJ, Cheng Z. Antibiotic resistance in Pseudomonas aeruginosa: mechanisms and alternative therapeutic strategies. Biotechnol Adv 2018; 37:177-192. [PMID: 30500353 DOI: 10.1016/j.biotechadv.2018.11.013] [Citation(s) in RCA: 966] [Impact Index Per Article: 161.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/21/2018] [Accepted: 11/24/2018] [Indexed: 01/09/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is a leading cause of morbidity and mortality in cystic fibrosis patients and immunocompromised individuals. Eradication of P. aeruginosa has become increasingly difficult due to its remarkable capacity to resist antibiotics. Strains of Pseudomonas aeruginosa are known to utilize their high levels of intrinsic and acquired resistance mechanisms to counter most antibiotics. In addition, adaptive antibiotic resistance of P. aeruginosa is a recently characterized mechanism, which includes biofilm-mediated resistance and formation of multidrug-tolerant persister cells, and is responsible for recalcitrance and relapse of infections. The discovery and development of alternative therapeutic strategies that present novel avenues against P. aeruginosa infections are increasingly demanded and gaining more and more attention. Although mostly at the preclinical stages, many recent studies have reported several innovative therapeutic technologies that have demonstrated pronounced effectiveness in fighting against drug-resistant P. aeruginosa strains. This review highlights the mechanisms of antibiotic resistance in P. aeruginosa and discusses the current state of some novel therapeutic approaches for treatment of P. aeruginosa infections that can be further explored in clinical practice.
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Affiliation(s)
- Zheng Pang
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Renee Raudonis
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Tong-Jun Lin
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Pediatrics, IWK Health Centre, Halifax, NS B3K 6R8, Canada
| | - Zhenyu Cheng
- Department of Pathology, Dalhousie University, Halifax, NS B3H 4R2, Canada; Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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102
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Liu T, Zhang Y, Wan Q. Pseudomonas aeruginosa bacteremia among liver transplant recipients. Infect Drug Resist 2018; 11:2345-2356. [PMID: 30532566 PMCID: PMC6247952 DOI: 10.2147/idr.s180283] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas aeruginosa bacteremia remains as a life-threatening complication after liver transplantation (LT) and is intractable because of the high rate of drug resistance to commonly used antibiotics. To better understand the characteristics of this postoperative complication, PubMed and Embase searches as well as reference mining was done for relevant literature from the start of the databases through August 2018. Among LT recipients, the incidence of P. aeruginosa bacteremia ranged from 0.5% to 14.4% and mortality rates were up to 40%. Approximately 35% of all episodes of bloodstream infections (BSIs) were P. aeruginosa bacteremia, of which 47% were multidrug resistant and 63% were extensively drug resistant. Several factors are known to affect the mortality of LT recipients with P. aeruginosa bacteremia, including hypotension, mechanical ventilation, and increasing severity of illness. In LT recipients with P. aeruginosa bacteremia, alteration in DNA gyrase A genes and overexpression of proteins involved in efflux systems, namely the expression of KPC-2-type carbapenemase, NDM-1, and VIM-2-type MBL, contribute to the high resistance of P. aeruginosa to a wide variety of antibiotics. Because of complicated mechanisms of drug resistance, P. aeruginosa causes high morbidity and mortality in bacteremic LT patients. Consequently, early detection and treatment with adequate early targeted coverage for P. aeruginosa BSI are of paramount importance in the early posttransplantation period to obtain a better prognosis for LT patients.
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Affiliation(s)
- Taohua Liu
- Xiangya School of Medicine, Central South University, Changsha 410083, China
| | - Yuezhong Zhang
- Xiangya School of Medicine, Central South University, Changsha 410083, China
| | - Qiquan Wan
- Department of Transplant Surgery, The Third Xiangya Hospital, Central South University, Changsha 410013, China,
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103
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Beaudoin T, Stone TA, Glibowicka M, Adams C, Yau Y, Ahmadi S, Bear CE, Grasemann H, Waters V, Deber CM. Activity of a novel antimicrobial peptide against Pseudomonas aeruginosa biofilms. Sci Rep 2018; 8:14728. [PMID: 30283025 PMCID: PMC6170476 DOI: 10.1038/s41598-018-33016-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/17/2018] [Indexed: 11/09/2022] Open
Abstract
With the increasing recognition of biofilms in human disease, the development of novel antimicrobial therapies is of critical importance. For example, in patients with cystic fibrosis (CF), the acquisition of host-adapted, chronic Pseudomonas aeruginosa infection is associated with a decline in lung function and increased mortality. Our objective was to test the in vitro efficacy of a membrane-active antimicrobial peptide we designed, termed 6K-F17 (sequence: KKKKKK-AAFAAWAAFAA-NH2), against multidrug resistant P. aeruginosa biofilms. This peptide displays high antimicrobial activity against a range of pathogenic bacteria, yet is non-hemolytic to human erythrocytes and non-toxic to human bronchial epithelial cells. In the present work, P. aeruginosa strain PAO1, and four multidrug resistant (MDR) isolates from chronically infected CF individuals, were grown as 48-hour biofilms in a static biofilm slide chamber model. These biofilms were then exposed to varying concentrations of 6K-F17 alone, or in the presence of tobramycin, prior to confocal imaging. Biofilm biovolume and viability were assessed. 6K-F17 was able to kill biofilms - even in the presence of sputum - and greatly reduce biofilm biovolume in PAO1 and MDR isolates. Strikingly, when used in conjunction with tobramycin, low doses of 6K-F17 significantly potentiated tobramycin killing, leading to biofilm destruction.
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Affiliation(s)
- Trevor Beaudoin
- Division of Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Tracy A Stone
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Miroslawa Glibowicka
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Christina Adams
- Division of Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Yvonne Yau
- Division of Microbiology, Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Saumel Ahmadi
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Christine E Bear
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Hartmut Grasemann
- Division of Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,Division of Respiratory Medicine, Department of Pediatrics, Hospital for Sick Children, Toronto, Canada
| | - Valerie Waters
- Division of Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, M5G 1X8, Canada
| | - Charles M Deber
- Division of Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada. .,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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104
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Apostolakos I, Piccirillo A. A review on the current situation and challenges of colistin resistance in poultry production. Avian Pathol 2018; 47:546-558. [DOI: 10.1080/03079457.2018.1524573] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Ilias Apostolakos
- Department of Comparative Biomedicine and Food Science, University of Padua, Legnaro, Italy
| | - Alessandra Piccirillo
- Department of Comparative Biomedicine and Food Science, University of Padua, Legnaro, Italy
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105
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Wee BA, Tai AS, Sherrard LJ, Ben Zakour NL, Hanks KR, Kidd TJ, Ramsay KA, Lamont I, Whiley DM, Bell SC, Beatson SA. Whole genome sequencing reveals the emergence of a Pseudomonas aeruginosa shared strain sub-lineage among patients treated within a single cystic fibrosis centre. BMC Genomics 2018; 19:644. [PMID: 30165811 PMCID: PMC6117919 DOI: 10.1186/s12864-018-5018-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/14/2018] [Indexed: 11/18/2022] Open
Abstract
Background Chronic lung infections caused by Pseudomonas aeruginosa are a significant cause of morbidity and mortality in people with cystic fibrosis (CF). Shared P. aeruginosa strains, that can be transmitted between patients, are of concern and in Australia the AUST-02 shared strain is predominant in individuals attending CF centres in Queensland and Western Australia. M3L7 is a multidrug resistant sub-type of AUST-02 that was recently identified in a Queensland CF centre and was shown to be associated with poorer clinical outcomes. The main aim of this study was to resolve the relationship of the emergent M3L7 sub-type within the AUST-02 group of strains using whole genome sequencing. Results A whole genome core phylogeny of 63 isolates indicated that M3L7 is a monophyletic sub-lineage within the context of the broader AUST-02 group. Relatively short branch lengths connected all of the M3L7 isolates. A phylogeny based on nucleotide polymorphisms present across the genome showed that the chronological estimation of the most recent common ancestor was around 2001 (± 3 years). SNP differences between sequential non-hypermutator M3L7 isolates collected 3–4 years apart from five patients suggested both continuous infection of the same strain and cross-infection of some M3L7 variants between patients. The majority of polymorphisms that were characteristic of M3L7 (i.e. acquired after divergence from all other AUST-02 isolates sequenced) were found to produce non-synonymous mutations in virulence and antibiotic resistance genes. Conclusions M3L7 has recently diverged from a common ancestor, indicating descent from a single carrier at a CF treatment centre in Australia. Both adaptation to the lung and transmission of M3L7 between adults attending this centre may have contributed to its rapid dissemination. Further genomic investigations are required on multiple intra-sample isolates of this sub-type to decipher potential mechanisms which facilitates its epidemiological success. Electronic supplementary material The online version of this article (10.1186/s12864-018-5018-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bryan A Wee
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Present Address: Usher Institute of Population Health Sciences & Informatics, University of Edinburgh, Edinburgh, United Kingdom
| | - Anna S Tai
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,Adult Cystic Fibrosis Centre, Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia.,Department of Respiratory Medicine, Western Australia Adult Cystic Fibrosis Centre, Sir Charles Gairdner Hospital, Nedlands, WA, Australia
| | - Laura J Sherrard
- Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,Present Address: School of Pharmacy, Queen's University Belfast, Belfast, United Kingdom
| | - Nouri L Ben Zakour
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Kirt R Hanks
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy J Kidd
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Centre for Experimental Medicine, Queen's University Belfast, Belfast, UK.,Child Health Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Kay A Ramsay
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,Present Address: Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Iain Lamont
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - David M Whiley
- Faculty of Medicine, UQ Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia.,Microbiology Department, Pathology Queensland Central Laboratory, Brisbane, QLD, Australia
| | - Scott C Bell
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.,Adult Cystic Fibrosis Centre, Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia.,Lung Bacteria Group, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia. .,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia. .,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, Australia.
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106
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Widely Used Benzalkonium Chloride Disinfectants Can Promote Antibiotic Resistance. Appl Environ Microbiol 2018; 84:AEM.01201-18. [PMID: 29959242 DOI: 10.1128/aem.01201-18] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 06/23/2018] [Indexed: 01/15/2023] Open
Abstract
While the misuse of antibiotics has clearly contributed to the emergence and proliferation of resistant bacterial pathogens, with major health consequences, it remains less clear if the widespread use of disinfectants, such as benzalkonium chlorides (BAC), a different class of biocides than antibiotics, has contributed to this problem. Here, we provide evidence that exposure to BAC coselects for antibiotic-resistant bacteria and describe the underlying genetic mechanisms. After inoculation with river sediment, BAC-fed bioreactors selected for several bacterial taxa, including the opportunistic pathogen Pseudomonas aeruginosa, that were more resistant to several antibiotics than their counterparts in a control (no BAC) bioreactor. A metagenomic analysis of the bioreactor microbial communities, confirmed by gene cloning experiments with the derived isolates, suggested that integrative and conjugative elements encoding a BAC efflux pump together with antibiotic resistance genes were responsible for these results. Furthermore, the exposure of the P. aeruginosa isolates to increasing concentrations of BAC selected for mutations in pmrB (polymyxin resistance) and physiological adaptations that contributed to a higher tolerance to polymyxin B and other antibiotics. The physiological adaptations included the overexpression of mexCD-oprJ multidrug efflux pump genes when BAC was added in the growth medium at subinhibitory concentrations. Collectively, our results demonstrated that disinfectants promote antibiotic resistance via several mechanisms and highlight the need to remediate (degrade) disinfectants in nontarget environments to further restrain the spread of antibiotic-resistant bacteria.IMPORTANCE Benzalkonium chlorides (BAC) are biocides broadly used in disinfectant solutions. Disinfectants are widely used in food processing lines, domestic households, and pharmaceutical products and are typically designed to have a different mode of action than antibiotics to avoid interfering with the use of the latter. Whether exposure to BAC makes bacteria more resistant to antibiotics remains an unresolved issue of obvious practical consequences for public health. Using an integrated approach that combines metagenomics of natural microbial communities with gene cloning experiments with isolates and experimental evolution assays, we show that the widely used benzalkonium chloride disinfectants promote clinically relevant antibiotic resistance. Therefore, more attention should be given to the usage of these disinfectants, and their fate in nontarget environments should be monitored more tightly.
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107
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Bricio-Moreno L, Sheridan VH, Goodhead I, Armstrong S, Wong JKL, Waters EM, Sarsby J, Panagiotou S, Dunn J, Chakraborty A, Fang Y, Griswold KE, Winstanley C, Fothergill JL, Kadioglu A, Neill DR. Evolutionary trade-offs associated with loss of PmrB function in host-adapted Pseudomonas aeruginosa. Nat Commun 2018; 9:2635. [PMID: 29980663 PMCID: PMC6035264 DOI: 10.1038/s41467-018-04996-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 06/06/2018] [Indexed: 12/22/2022] Open
Abstract
Pseudomonas aeruginosa colonises the upper airway of cystic fibrosis (CF) patients, providing a reservoir of host-adapted genotypes that subsequently establish chronic lung infection. We previously experimentally-evolved P. aeruginosa in a murine model of respiratory tract infection and observed early-acquired mutations in pmrB, encoding the sensor kinase of a two-component system that promoted establishment and persistence of infection. Here, using proteomics, we show downregulation of proteins involved in LPS biosynthesis, antimicrobial resistance and phenazine production in pmrB mutants, and upregulation of proteins involved in adherence, lysozyme resistance and inhibition of the chloride ion channel CFTR, relative to wild-type strain LESB65. Accordingly, pmrB mutants are susceptible to antibiotic treatment but show enhanced adherence to airway epithelial cells, resistance to lysozyme treatment, and downregulate host CFTR expression. We propose that P. aeruginosa pmrB mutations in CF patients are subject to an evolutionary trade-off, leading to enhanced colonisation potential, CFTR inhibition, and resistance to host defences, but also to increased susceptibility to antibiotics.
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Affiliation(s)
- Laura Bricio-Moreno
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Victoria H Sheridan
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Ian Goodhead
- School of Environment and Life Sciences, University of Salford, Salford, M5 4WT, UK
| | - Stuart Armstrong
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
- NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, L69 3GL, UK
| | - Janet K L Wong
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Elaine M Waters
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
- Department of Microbiology, School of Natural Science, National University of Ireland, Galway, H91 TK33, Ireland
| | - Joscelyn Sarsby
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Stavros Panagiotou
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - James Dunn
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Adrita Chakraborty
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Yongliang Fang
- Thayer School of Engineering, Dartmouth, Hanover, NH, 03755, USA
| | - Karl E Griswold
- Thayer School of Engineering, Dartmouth, Hanover, NH, 03755, USA
| | - Craig Winstanley
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Joanne L Fothergill
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK.
| | - Aras Kadioglu
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Daniel R Neill
- Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK.
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108
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Phan MD, Nhu NTK, Achard MES, Forde BM, Hong KW, Chong TM, Yin WF, Chan KG, West NP, Walker MJ, Paterson DL, Beatson SA, Schembri MA. Modifications in the pmrB gene are the primary mechanism for the development of chromosomally encoded resistance to polymyxins in uropathogenic Escherichia coli. J Antimicrob Chemother 2018; 72:2729-2736. [PMID: 29091192 DOI: 10.1093/jac/dkx204] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/26/2017] [Indexed: 01/08/2023] Open
Abstract
Objectives Polymyxins remain one of the last-resort drugs to treat infections caused by MDR Gram-negative pathogens. Here, we determined the mechanisms by which chromosomally encoded resistance to colistin and polymyxin B can arise in the MDR uropathogenic Escherichia coli ST131 reference strain EC958. Methods Two complementary approaches, saturated transposon mutagenesis and spontaneous mutation induction with high concentrations of colistin and polymyxin B, were employed to select for mutations associated with resistance to polymyxins. Mutants were identified using transposon-directed insertion-site sequencing or Illumina WGS. A resistance phenotype was confirmed by MIC and further investigated using RT-PCR. Competitive growth assays were used to measure fitness cost. Results A transposon insertion at nucleotide 41 of the pmrB gene (EC958pmrB41-Tn5) enhanced its transcript level, resulting in a 64- and 32-fold increased MIC of colistin and polymyxin B, respectively. Three spontaneous mutations, also located within the pmrB gene, conferred resistance to both colistin and polymyxin B with a corresponding increase in transcription of the pmrCAB genes. All three mutations incurred a fitness cost in the absence of colistin and polymyxin B. Conclusions This study identified the pmrB gene as the main chromosomal target for induction of colistin and polymyxin B resistance in E. coli.
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Affiliation(s)
- Minh-Duy Phan
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Nguyen Thi Khanh Nhu
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Maud E S Achard
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Brian M Forde
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland, Australia
| | - Kar Wai Hong
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala, Lumpur, Malaysia
| | - Teik Min Chong
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala, Lumpur, Malaysia
| | - Wai-Fong Yin
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala, Lumpur, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala, Lumpur, Malaysia
| | - Nicholas P West
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - Mark J Walker
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
| | - David L Paterson
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,The University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Scott A Beatson
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia.,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland, Australia
| | - Mark A Schembri
- School of Chemistry & Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Queensland, Australia
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109
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Jiménez-Guerra G, Heras-Cañas V, Gutiérrez-Soto M, Del Pilar Aznarte-Padial M, Expósito-Ruiz M, Navarro-Marí JM, Gutiérrez-Fernández J. Urinary tract infection by Acinetobacter baumannii and Pseudomonas aeruginosa: evolution of antimicrobial resistance and therapeutic alternatives. J Med Microbiol 2018; 67:790-797. [PMID: 29693543 DOI: 10.1099/jmm.0.000742] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose. Acinetobacter baumannii and Pseudomonas aeruginosa are responsible for numerous nosocomial infections. The objective of this study was to determine the development of their susceptibility to ten antibiotics and the antibiotic consumption of patients with suspicion of urinary tract infection (UTI).Methodology. A retrospective study was conducted on the susceptibility profiles of A. baumannii and P. aeruginosa isolates from 749 urine samples gathered between January 2013 and December 2016, and on the consumption of imipenem, meropenem and piperacillin-tazobactam between 2014 and 2016.Results. Hospital patients were the source of 82 (91.1 %) of the 90 A. baumannii isolates detected and 555 (84.2 %) of the 659 P. aeruginosa isolates. Globally, the lowest percentage susceptibility values were found for fosfomycin, aztreonam and ciprofloxacin, while colistin continued to be the most active antibiotic in vitro. In 2016, the susceptibility of A. baumannii to carbapenem and piperacillin-tazobactam decreased to very low values, while the susceptibility of P. aeruginosa to carbapenem remained stable but its susceptibility to piperacillin-tazobactam decreased. There was a marked increase in the consumption of piperacillin-tazobactam.Conclusion. In our setting, it is no longer possible to use carbapenems and piperacillin-tazobactam for empirical treatment of UTI due to A. baumannii or to use piperacillin-tazobactam for empirical treatment of UTI due to P. aeruginosa. Colistin was found to be the most active antibiotic in vitro. There was a marked increase in the consumption of piperacillin-tazobactam.
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Affiliation(s)
- Gemma Jiménez-Guerra
- Laboratorio de Microbiología, Hospital Virgen de las Nieves-Instituto de Investigación Biosanitaria de Granada, Granada, Spain
| | - Victor Heras-Cañas
- Laboratorio de Microbiología, Hospital Virgen de las Nieves-Instituto de Investigación Biosanitaria de Granada, Granada, Spain
| | | | | | - Manuela Expósito-Ruiz
- Unidad de Metodología de la Investigación y Bioestadística. Hospital Virgen de las Nieves-Instituto de Investigación Biosanitaria de Granada, Granada, Spain
| | - José María Navarro-Marí
- Laboratorio de Microbiología, Hospital Virgen de las Nieves-Instituto de Investigación Biosanitaria de Granada, Granada, Spain
| | - José Gutiérrez-Fernández
- Laboratorio de Microbiología, Hospital Virgen de las Nieves-Instituto de Investigación Biosanitaria de Granada, Granada, Spain.,Departamento de Microbiología, Facultad de Medicina, Universidad de Granada-Instituto de Investigación Biosanitaria de Granada, Granada, Spain
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110
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Genomic and Transcriptomic Insights into How Bacteria Withstand High Concentrations of Benzalkonium Chloride Biocides. Appl Environ Microbiol 2018; 84:AEM.00197-18. [PMID: 29654181 DOI: 10.1128/aem.00197-18] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/09/2018] [Indexed: 12/31/2022] Open
Abstract
Benzalkonium chlorides (BAC) are commonly used biocides in broad-spectrum disinfectant solutions. How microorganisms cope with BAC exposure remains poorly understood, despite its importance for disinfection and disinfectant-induced antibiotic resistance. To provide insights into these issues, we exposed two isolates of an opportunistic pathogen, Pseudomonas aeruginosa, to increasing concentrations of BAC. One isolate was preadapted to BAC, as it originated from a bioreactor fed with subinhibitory concentrations of BAC for 3 years, while the other originated from a bioreactor that received no BAC. Replicated populations of both isolates were able to survive high concentrations of BAC, up to 1,200 and 1,600 mg/liter for the non- and preadapted strains, respectively, exceeding typical application doses. Transcriptome sequencing (RNA-seq) analysis revealed upregulation of efflux pump genes and decreased expression of porins related to BAC transport as well as reduced growth rate. Increased expression of spermidine (a polycation) synthase genes and mutations in the pmrB (polymyxin resistance) gene, which cause a reduction in membrane negative charge, suggested that a major adaptation to exposure to the cationic surfactant BAC was to actively stabilize cell surface charge. Collectively, these results revealed that P. aeruginosa adapts to BAC exposure by a combination of mechanisms and provided genetic markers to monitor BAC-resistant organisms that may have applications in the practice of disinfection.IMPORTANCE BAC are widely used as biocides in disinfectant solutions, food-processing lines, domestic households, and health care facilities. Due to their wide use and mode of action, there has been rising concern that BAC may promote antibiotic resistance. Consistent with this idea, at least 40 outbreaks have been attributed to infection by disinfectant- and antibiotic-resistant pathogens such as P. aeruginosa However, the underlying molecular mechanisms that bacteria use to deal with BAC exposure remain poorly elucidated. Elucidating these mechanisms may be important for monitoring and limiting the spread of disinfectant-resistant pathogens. Using an integrated approach that combined genomics and transcriptomics with physiological characterization of BAC-adapted isolates, this study provided a comprehensive understanding of the BAC resistance mechanisms in P. aeruginosa Our findings also revealed potential genetic markers to detect and monitor the abundance of BAC-resistant pathogens across clinical or environmental settings. This work contributes new knowledge about high concentrations of benzalkonium chlorides disinfectants-resistance mechanisms at the whole-cell genomic and transcriptomic level.
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Alterations of Metabolic and Lipid Profiles in Polymyxin-Resistant Pseudomonas aeruginosa. Antimicrob Agents Chemother 2018; 62:AAC.02656-17. [PMID: 29632014 DOI: 10.1128/aac.02656-17] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 04/05/2018] [Indexed: 12/27/2022] Open
Abstract
Multidrug-resistant Pseudomonas aeruginosa presents a global medical challenge, and polymyxins are a key last-resort therapeutic option. Unfortunately, polymyxin resistance in P. aeruginosa has been increasingly reported. The present study was designed to define metabolic differences between paired polymyxin-susceptible and -resistant P. aeruginosa strains using untargeted metabolomics and lipidomics analyses. The metabolomes of wild-type P. aeruginosa strain K ([PAK] polymyxin B MIC, 1 mg/liter) and its paired pmrB mutant strains, PAKpmrB6 and PAKpmrB12 (polymyxin B MICs of 16 mg/liter and 64 mg/liter, respectively) were characterized using liquid chromatography-mass spectrometry, and metabolic differences were identified through multivariate and univariate statistics. PAKpmrB6 and PAKpmrB12, which displayed lipid A modifications with 4-amino-4-deoxy-l-arabinose, showed significant perturbations in amino acid and carbohydrate metabolism, particularly the intermediate metabolites from 4-amino-4-deoxy-l-arabinose synthesis and the methionine salvage cycle pathways. The genomics result showed a premature termination (Y275stop) in speE (encoding spermidine synthase) in PAKpmrB6, and metabolomics data revealed a decreased intracellular level of spermidine in PAKpmrB6 compared to that in PAKpmrB12 Our results indicate that spermidine may play an important role in high-level polymyxin resistance in P. aeruginosa Interestingly, both pmrB mutants had decreased levels of phospholipids, fatty acids, and acyl-coenzyme A compared to those in the wild-type PAK. Moreover, the more resistant PAKpmrB12 mutant exhibited much lower levels of phospholipids than the PAKpmrB6 mutant, suggesting that the decreased phospholipid level was associated with polymyxin resistance. In summary, this study provides novel mechanistic information on polymyxin resistance in P. aeruginosa and highlights its impacts on bacterial metabolism.
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Desriac F, Clamens T, Rosay T, Rodrigues S, Tahrioui A, Enault J, Roquigny L, Racine PJ, Taupin L, Bazire A, Dufour A, Leprince J, Bouffartigues E, Chevalier S, Feuilloley MGJ, Lesouhaitier O. Different Dose-Dependent Modes of Action of C-Type Natriuretic Peptide on Pseudomonas aeruginosa Biofilm Formation. Pathogens 2018; 7:pathogens7020047. [PMID: 29695043 PMCID: PMC6026938 DOI: 10.3390/pathogens7020047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/16/2018] [Accepted: 04/20/2018] [Indexed: 01/16/2023] Open
Abstract
We have previously shown that the C-type Natriuretic Peptide (CNP), a peptide produced by lungs, is able to impact Pseudomonasaeruginosa physiology. In the present work, the effect of CNP at different concentrations on P. aeruginosa biofilm formation was studied and the mechanisms of action of this human hormone on P. aeruginosa were deciphered. CNP was shown to inhibit dynamic biofilm formation in a dose-dependent manner without affecting the bacterial growth at any tested concentrations. The most effective concentrations were 1 and 0.1 µM. At 0.1 µM, the biofilm formation inhibition was fully dependent on the CNP sensor protein AmiC, whereas it was only partially AmiC-dependent at 1 µM, revealing the existence of a second AmiC-independent mode of action of CNP on P. aeruginosa. At 1 µM, CNP reduced both P. aeruginosa adhesion on glass and di-rhamnolipid production and also increased the bacterial membrane fluidity. The various effects of CNP at 1 µM and 0.1 µM on P. aeruginosa shown here should have major consequences to design drugs for biofilm treatment or prevention.
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Affiliation(s)
- Florie Desriac
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Thomas Clamens
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Thibaut Rosay
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Sophie Rodrigues
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
| | - Ali Tahrioui
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Jérémy Enault
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Lucille Roquigny
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Pierre-Jean Racine
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Laure Taupin
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
| | - Alexis Bazire
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
| | - Alain Dufour
- Laboratoire de Biotechnologie et Chimie Marines (LBCM), EA 3884, LBCM, IUEM Université de Bretagne-Sud, 56100 Lorient, France.
| | - Jérôme Leprince
- Inserm U1239, PRIMACEN, Normandie Université, IRIB, Université de Rouen, 76000 Rouen, France.
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandie Université, University Rouen-Normandy, 27000 Evreux, France.
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Lima WG, Alves MC, Cruz WS, Paiva MC. Chromosomally encoded and plasmid-mediated polymyxins resistance in Acinetobacter baumannii: a huge public health threat. Eur J Clin Microbiol Infect Dis 2018. [PMID: 29524060 DOI: 10.1007/s10096-018-3223-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Acinetobacter baumannii is an opportunistic pathogen associated with nosocomial and community infections of great clinical relevance. Its ability to rapidly develop resistance to antimicrobials, especially carbapenems, has re-boosted the prescription and use of polymyxins. However, the emergence of strains resistant to these antimicrobials is becoming a critical issue in several regions of the world because very few of currently available antibiotics are effective in these cases. This review summarizes the most up-to-date knowledge about chromosomally encoded and plasmid-mediated polymyxins resistance in A. baumannii. Different mechanisms are employed by A. baumannii to overcome the antibacterial effects of polymyxins. Modification of the outer membrane through phosphoethanolamine addition, loss of lipopolysaccharide, symmetric rupture, metabolic changes affecting osmoprotective amino acids, and overexpression of efflux pumps are involved in this process. Several genetic elements modulate these mechanisms, but only three of them have been described so far in A. baumannii clinical isolates such as mutations in pmrCAB, lpxACD, and lpsB. Elucidation of genotypic profiles and resistance mechanisms are necessary for control and fight against resistance to polymyxins in A. baumannii, thereby protecting this class for future treatment.
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Affiliation(s)
- William Gustavo Lima
- Laboratory of Medical Microbiology, Central-West Campus Dona Lindu, Federal University of São João del-Rei, Rua Sebastião Gonçalves Coelho, 400, Divinopolis, Minas Gerais, 35501-293, Brazil.
| | - Mara Cristina Alves
- Laboratory of Laboratorial Diagnostic and Clinical Microbiology, Central-West Campus Dona Lindu, Federal University of São João del-Rei, Divinopolis, MG, Brazil
| | - Waleska Stephanie Cruz
- Laboratory of Molecular and Celular Biology, Alto Paraopeba Campus, Federal University of São João del-Rei, Ouro Branco, MG, Brazil
| | - Magna Cristina Paiva
- Laboratory of Laboratorial Diagnostic and Clinical Microbiology, Central-West Campus Dona Lindu, Federal University of São João del-Rei, Divinopolis, MG, Brazil
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Sengyee S, Yoon SH, Paksanont S, Yimthin T, Wuthiekanun V, Limmathurotsakul D, West TE, Ernst RK, Chantratita N. Comprehensive analysis of clinical Burkholderia pseudomallei isolates demonstrates conservation of unique lipid A structure and TLR4-dependent innate immune activation. PLoS Negl Trop Dis 2018; 12:e0006287. [PMID: 29474381 PMCID: PMC5842036 DOI: 10.1371/journal.pntd.0006287] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 03/07/2018] [Accepted: 01/31/2018] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei is an environmental bacterium that causes melioidosis, a major community-acquired infection in tropical regions. Melioidosis presents with a range of clinical symptoms, is often characterized by a robust inflammatory response, may relapse after treatment, and results in high mortality rates. Lipopolysaccharide (LPS) of B. pseudomallei is a potent immunostimulatory molecule comprised of lipid A, core, and O-polysaccharide (OPS) components. Four B. pseudomallei LPS types have been described based on SDS-PAGE patterns that represent the difference of OPS-type A, type B, type B2 and rough LPS. The majority of B. pseudomallei isolates are type A. We used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) followed by electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QqTOF MS) and gas chromatography to characterize the lipid A of B. pseudomallei within LPS type A isolates. We determined that B. pseudomallei lipid A is represented by penta- and tetra-acylated species modified with 4-amino-4-deoxy-arabinose (Ara4N). The MALDI-TOF profiles from 171 clinical B. pseudomallei isolates, including 68 paired primary and relapse isolates and 35 within-host isolates were similar. We did not observe lipid A structural changes when the bacteria were cultured in different growth conditions. Dose-dependent NF-κB activation in HEK cells expressing TLR4 was observed using multiple heat-killed B. pseudomallei isolates and corresponding purified LPS. We demonstrated that TLR4-dependent NF-κB activation induced by heat-killed bacteria or LPS prepared from OPS deficient mutant was significantly greater than those induced by wild type B. pseudomallei. These findings suggest that the structure of B. pseudomallei lipid A is highly conserved in a wide variety of clinical and environmental circumstances but that the presence of OPS may modulate LPS-driven innate immune responses in melioidosis.
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Affiliation(s)
- Sineenart Sengyee
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sung Hwan Yoon
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States of America
| | - Suporn Paksanont
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thatcha Yimthin
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Vanaporn Wuthiekanun
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Direk Limmathurotsakul
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - T. Eoin West
- Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, WA, United States of America
- International Respiratory and Severe Illness Center, University of Washington, Seattle, WA, United States of America
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, United States of America
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- * E-mail:
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115
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Han ML, Velkov T, Zhu Y, Roberts KD, Le Brun AP, Chow SH, Gutu AD, Moskowitz SM, Shen HH, Li J. Polymyxin-Induced Lipid A Deacylation in Pseudomonas aeruginosa Perturbs Polymyxin Penetration and Confers High-Level Resistance. ACS Chem Biol 2018; 13:121-130. [PMID: 29182311 DOI: 10.1021/acschembio.7b00836] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Polymyxins are last-line antibiotics against life-threatening multidrug-resistant Gram-negative bacteria. Unfortunately, polymyxin resistance is increasingly reported, leaving a total lack of therapies. Using lipidomics and transcriptomics, we discovered that polymyxin B induced lipid A deacylation via pagL in both polymyxin-resistant and -susceptible Pseudomonas aeruginosa. Our results demonstrated that the deacylation of lipid A is an "innate immunity" response to polymyxins and a key compensatory mechanism to the aminoarabinose modification to confer high-level polymyxin resistance in P. aeruginosa. Furthermore, cutting-edge neutron reflectometry studies revealed that an assembled outer membrane (OM) with the less hydrophobic penta-acylated lipid A decreased polymyxin B penetration, compared to the hexa-acylated form. Polymyxin analogues with enhanced hydrophobicity displayed superior penetration into the tail regions of the penta-acylated lipid A OM. Our findings reveal a previously undiscovered mechanism of polymyxin resistance, wherein polymyxin-induced lipid A remodeling affects the OM packing and hydrophobicity, perturbs polymyxin penetration, and thereby confers high-level resistance.
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Affiliation(s)
- Mei-Ling Han
- Monash
Institute of Pharmaceutical Sciences, Monash University, 381 Royal
Parade, Parkville, Victoria 3052, Australia
- Monash
Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Tony Velkov
- Monash
Institute of Pharmaceutical Sciences, Monash University, 381 Royal
Parade, Parkville, Victoria 3052, Australia
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Yan Zhu
- Monash
Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Kade D. Roberts
- Monash
Institute of Pharmaceutical Sciences, Monash University, 381 Royal
Parade, Parkville, Victoria 3052, Australia
| | - Anton P. Le Brun
- Australian
Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee
DC, New South Wales 2232, Australia
| | - Seong Hoong Chow
- Monash
Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Alina D. Gutu
- Department
of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts United States
| | | | - Hsin-Hui Shen
- Monash
Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
- Department
of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Jian Li
- Monash
Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
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116
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Francis VI, Stevenson EC, Porter SL. Two-component systems required for virulence in Pseudomonas aeruginosa. FEMS Microbiol Lett 2018; 364:3828290. [PMID: 28510688 PMCID: PMC5812489 DOI: 10.1093/femsle/fnx104] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 05/15/2017] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a versatile opportunistic pathogen capable of infecting a broad range of hosts, in addition to thriving in a broad range of environmental conditions outside of hosts. With this versatility comes the need to tightly regulate its genome to optimise its gene expression and behaviour to the prevailing conditions. Two-component systems (TCSs) comprising sensor kinases and response regulators play a major role in this regulation. This minireview discusses the growing number of TCSs that have been implicated in the virulence of P. aeruginosa, with a special focus on the emerging theme of multikinase networks, which are networks comprising multiple sensor kinases working together, sensing and integrating multiple signals to decide upon the best response. The networks covered in depth regulate processes such as the switch between acute and chronic virulence (GacS network), the Cup fimbriae (Roc network and Rcs/Pvr network), the aminoarabinose modification of lipopolysaccharide (a network involving the PhoQP and PmrBA TCSs), twitching motility and virulence (a network formed from the Chp chemosensory pathway and the FimS/AlgR TCS), and biofilm formation (Wsp chemosensory pathway). In addition, we highlight the important interfaces between these systems and secondary messenger signals such as cAMP and c-di-GMP.
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Affiliation(s)
- Vanessa I Francis
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
| | - Emma C Stevenson
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
| | - Steven L Porter
- Biosciences, Geoffrey Pope Building, College of Life and Environmental Sciences, University of Exeter, Exeter EX 4QD, UK
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117
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Zamyatina A. Aminosugar-based immunomodulator lipid A: synthetic approaches. Beilstein J Org Chem 2018; 14:25-53. [PMID: 29379577 PMCID: PMC5769089 DOI: 10.3762/bjoc.14.3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 10/23/2017] [Indexed: 12/11/2022] Open
Abstract
The immediate immune response to infection by Gram-negative bacteria depends on the structure of a lipopolysaccharide (LPS, also known as endotoxin), a complex glycolipid constituting the outer leaflet of the bacterial outer membrane. Recognition of picomolar quantities of pathogenic LPS by the germ-line encoded Toll-like Receptor 4 (TLR4) complex triggers the intracellular pro-inflammatory signaling cascade leading to the expression of cytokines, chemokines, prostaglandins and reactive oxygen species which manifest an acute inflammatory response to infection. The "endotoxic principle" of LPS resides in its amphiphilic membrane-bound fragment glycophospholipid lipid A which directly binds to the TLR4·MD-2 receptor complex. The lipid A content of LPS comprises a complex mixture of structural homologs varying in the acylation pattern, the length of the (R)-3-hydroxyacyl- and (R)-3-acyloxyacyl long-chain residues and in the phosphorylation status of the β(1→6)-linked diglucosamine backbone. The structural heterogeneity of the lipid A isolates obtained from bacterial cultures as well as possible contamination with other pro-inflammatory bacterial components makes it difficult to obtain unambiguous immunobiological data correlating specific structural features of lipid A with its endotoxic activity. Advanced understanding of the therapeutic significance of the TLR4-mediated modulation of the innate immune signaling and the central role of lipid A in the recognition of LPS by the innate immune system has led to a demand for well-defined materials for biological studies. Since effective synthetic chemistry is a prerequisite for the availability of homogeneous structurally distinct lipid A, the development of divergent and reproducible approaches for the synthesis of various types of lipid A has become a subject of considerable importance. This review focuses on recent advances in synthetic methodologies toward LPS substructures comprising lipid A and describes the synthesis and immunobiological properties of representative lipid A variants corresponding to different bacterial species. The main criteria for the choice of orthogonal protecting groups for hydroxyl and amino functions of synthetically assembled β(1→6)-linked diglucosamine backbone of lipid A which allows for a stepwise introduction of multiple functional groups into the molecule are discussed. Thorough consideration is also given to the synthesis of 1,1'-glycosyl phosphodiesters comprising partial structures of 4-amino-4-deoxy-β-L-arabinose modified Burkholderia lipid A and galactosamine-modified Francisella lipid A. Particular emphasis is put on the stereoselective construction of binary glycosyl phosphodiester fragments connecting the anomeric centers of two aminosugars as well as on the advanced P(III)-phosphorus chemistry behind the assembly of zwitterionic double glycosyl phosphodiesters.
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Affiliation(s)
- Alla Zamyatina
- Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
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118
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Casabuono AC, Czibener C, Del Giudice MG, Valguarnera E, Ugalde JE, Couto AS. New Features in the Lipid A Structure of Brucella suis and Brucella abortus Lipopolysaccharide. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2716-2723. [PMID: 28924631 DOI: 10.1007/s13361-017-1805-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/18/2017] [Accepted: 08/26/2017] [Indexed: 06/07/2023]
Abstract
Brucellaceae are Gram-negative bacteria that cause brucellosis, one of the most distributed worldwide zoonosis, transmitted to humans by contact with either infected animals or their products. The lipopolysaccharide exposed on the cell surface has been intensively studied and is considered a major virulence factor of Brucella. In the last years, structural studies allowed the determination of new structures in the core oligosaccharide and the O-antigen of this lipopolysaccharide. In this work, we have reinvestigated the lipid A structure isolated from B. suis and B. abortus lipopolysaccharides. A detailed study by MALDI-TOF mass spectrometry in the positive and negative ion modes of the lipid A moieties purified from both species was performed. Interestingly, a new feature was detected: the presence of a pyrophosphorylethanolamine residue substituting the backbone. LID-MS/MS analysis of some of the detected ions allowed assurance that the Lipid A structure composed by the diGlcN3N disaccharide, mainly hexa-acylated and penta-acylated, bearing one phosphate and one pyrophosphorylethanolamine residue. Graphical abstract ᅟ.
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Affiliation(s)
- Adriana C Casabuono
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica - Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Investigación en Hidratos de Carbono (CIHIDECAR), Ciudad Universitaria, Intendente Güiraldes 2160, C1428GA, Buenos Aires, Argentina
| | - Cecilia Czibener
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Mariela G Del Giudice
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Ezequiel Valguarnera
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Juan E Ugalde
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Alicia S Couto
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica - Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Investigación en Hidratos de Carbono (CIHIDECAR), Ciudad Universitaria, Intendente Güiraldes 2160, C1428GA, Buenos Aires, Argentina.
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Transcriptional and Mutational Profiling of an Aminoglycoside-Resistant Pseudomonas aeruginosa Small-Colony Variant. Antimicrob Agents Chemother 2017; 61:AAC.01178-17. [PMID: 28874369 DOI: 10.1128/aac.01178-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/18/2017] [Indexed: 02/01/2023] Open
Abstract
Pseudomonas aeruginosa is a major causative agent of both acute and chronic infections. Although aminoglycoside antibiotics are very potent drugs against such infections, antibiotic failure is steadily increasing mainly because of increasing resistance of the bacteria. Many molecular mechanisms that determine resistance, such as acquisition of genes encoding aminoglycoside-inactivating enzymes or overexpression of efflux pumps, have been elucidated. However, there are additional, less well-described mechanisms of aminoglycoside resistance. In this study, we profiled a clinical tobramycin-resistant P. aeruginosa strain that exhibited a small-colony variant (SCV) phenotype. Both the resistance and colony morphology phenotypes were lost upon passage of the isolate under rich medium conditions. Transcriptional and mutational profiling revealed that the SCV harbored activating mutations in the two-component systems AmgRS and PmrAB. Introduction of these mutations individually into type strain PA14 conferred tobramycin and colistin resistance, respectively. However, their combined introduction had an additive effect on the tobramycin resistance phenotype. Activation of the AmgRS system slightly reduced the colony size of wild-type PA14, whereas the simultaneous overexpression of gacA, the response regulator of the GacSA two-component system, further reduced colony size. In conclusion, we uncovered combinatorial influences of two-component systems on clinically relevant phenotypes such as resistance and the expression of the SCV phenotype. Our results clearly demonstrate that the combined activation of P. aeruginosa two-component systems has pleiotropic effects with unforeseen consequences.
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Rapid and Consistent Evolution of Colistin Resistance in Extensively Drug-Resistant Pseudomonas aeruginosa during Morbidostat Culture. Antimicrob Agents Chemother 2017. [PMID: 28630206 DOI: 10.1128/aac.00043-17] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Colistin is a last-resort antibiotic commonly used against multidrug-resistant strains of Pseudomonas aeruginosa To investigate the potential for in situ evolution of resistance against colistin and to map the molecular targets of colistin resistance, we exposed two P. aeruginosa isolates to colistin using a continuous-culture device known as a morbidostat. As a result, colistin resistance reproducibly increased 10-fold within 10 days and 100-fold within 20 days, along with highly stereotypic yet strain-specific mutation patterns. The majority of mutations hit the pmrAB two-component signaling system and genes involved in lipopolysaccharide (LPS) synthesis, including lpxC, pmrE, and migA We tracked the frequencies of all arising mutations by whole-genome deep sequencing every 3 to 4 days to obtain a detailed picture of the dynamics of resistance evolution, including competition and displacement among multiple resistant subpopulations. In 7 out of 18 cultures, we observed mutations in mutS along with a mutator phenotype that seemed to facilitate resistance evolution.
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121
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Han ML, Shen HH, Hansford KA, Schneider EK, Sivanesan S, Roberts KD, Thompson PE, Le Brun AP, Zhu Y, Sani MA, Separovic F, Blaskovich MAT, Baker MA, Moskowitz SM, Cooper MA, Li J, Velkov T. Investigating the Interaction of Octapeptin A3 with Model Bacterial Membranes. ACS Infect Dis 2017; 3:606-619. [PMID: 28695731 DOI: 10.1021/acsinfecdis.7b00065] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Octapeptins are cyclic lipopeptides with a broader spectrum of activity against fungi and polymyxin-resistant Gram-negative and Gram-positive bacteria. In the present study, we investigated the interaction of octapeptin A3 with asymmetric outer membrane models of Gram-negative pathogen Pseudomonas aeruginosa using neutron reflectometry, together with fluorimetric and calorimetry methods. For the first time, our neutron reflectometry results reveal that the interaction of octapeptin A3 with the Gram-negative outer membrane involves an initial transient polar interaction with the phospholipid and lipid A headgroups, followed by the penetration of the entire octapeptin molecule into the fatty acyl core of the outer membrane. This mechanism contrasts with that of polymyxin B, which specifically targets lipid A, whereas octapeptins appear to target both lipid A and phospholipids. Furthermore, the mechanism of octapeptins does not appear to be highly dependent on an initial complementary electrostatic interaction with lipid A, which accounts for their ability to bind to lipid A of polymyxin-resistant Gram-negative bacteria that is modified with cationic moieties that act to electrostatically repel the cationic polymyxin molecule. The presented findings shed new light on the mechanism whereby octapeptins penetrate the outer membrane of polymyxin-resistant Gram-negative pathogens and highlight their potential as candidates for development as new antibiotics against problematic multi-drug-resistant pathogens.
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Affiliation(s)
- Mei-Ling Han
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | | | - Karl A. Hansford
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Elena K. Schneider
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Sivashangarie Sivanesan
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Kade D. Roberts
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Philip E. Thompson
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Anton P. Le Brun
- Bragg Institute, Australian
Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Yan Zhu
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Mark A. T. Blaskovich
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Mark A. Baker
- Priority Research Centre in Reproductive
Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Samuel M. Moskowitz
- Vertex Pharmaceuticals, 50 Northern Avenue, Boston, Massachusetts 02210, United States
| | - Matthew A. Cooper
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Tony Velkov
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
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122
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Chung ES, Lee JY, Rhee JY, Ko KS. Colistin resistance in Pseudomonas aeruginosa that is not linked to arnB. J Med Microbiol 2017. [PMID: 28621641 DOI: 10.1099/jmm.0.000456] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE It is known that the arnB (or pmrH) gene encoding uridine 5'-(beta-1-threo-pentapyranosyl-4-ulose diphosphate) aminotransferase plays a critical role in colistin resistance in Pseudomonas aeruginosa through the addition of 4-amino-4-deoxy-l-arabinose (l-Ara4N) to lipid A. In this study, we attempted to obtain a colistin-resistant mutant from an arnB-deleted mutant through exposure to colistin. METHODOLOGY We constructed an arnB deletion mutant (P5ΔarnB :: nptIII) from a colistin-susceptible strain (P5) by allelic replacement mutagenesis, and colistin-resistant mutants were selected in vitro using P5 and P5ΔarnB :: nptIII. The growth rate, lipid A structure, biofilm-forming activity and cell viability in diverse stressful conditions (osmotic, oxidative, acidic and heat stress) were investigated. Expression of phoP, pmrA, parR, and cprR was evaluated by qRT-PCR. RESULTS An arnB deletion mutant was shown to develop colistin resistance through the addition of l-Ara4N to lipid A, despite a low survival rate (over 1000-fold lower than that of the wild-type strain) in the media with colistin. Two colistin-resistant mutants showed higher survival rates than colistin-susceptible strains against 5 % NaCl. In the presence of acidic and heat stress, P5ΔarnB :: nptIII-CstR exhibited higher survival rates during conditions of 1 % HCl and 42 °C than the other strains. Both phoP and pmrA genes were overexpressed significantly in both colistin-resistant mutants, but parR and cprR genes were not. CONCLUSION We revealed that colistin resistance could be developed despite arnB deletion in P. aeruginosa through the addition of l-Ara4N to lipid A, which was accompanied by diverse physiological changes.
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Affiliation(s)
- Eun Seon Chung
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Ji-Young Lee
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Ji-Young Rhee
- Division of Infectious Diseases, Department of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Kwan Soo Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
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123
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Susceptibility of Colistin-Resistant, Gram-Negative Bacteria to Antimicrobial Peptides and Ceragenins. Antimicrob Agents Chemother 2017; 61:AAC.00292-17. [PMID: 28584137 PMCID: PMC5527650 DOI: 10.1128/aac.00292-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/20/2017] [Indexed: 11/20/2022] Open
Abstract
The susceptibility of colistin-resistant clinical isolates of Klebsiella pneumoniae to ceragenins and antimicrobial peptides (AMPs) suggests that there is little to no cross-resistance between colistin and ceragenins/AMPs and that lipid A modifications are found in bacteria with modest changes in susceptibility to ceragenins and with high levels of resistance to colistin. These results suggest that there are differences in the resistance mechanisms to colistin and ceragenins/AMPs.
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124
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Structural Modification of Lipopolysaccharide Conferred by mcr-1 in Gram-Negative ESKAPE Pathogens. Antimicrob Agents Chemother 2017; 61:AAC.00580-17. [PMID: 28373195 PMCID: PMC5444183 DOI: 10.1128/aac.00580-17] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 03/31/2017] [Indexed: 11/20/2022] Open
Abstract
mcr-1 was initially reported as the first plasmid-mediated colistin resistance gene in clinical isolates of Escherichia coli and Klebsiella pneumoniae in China and has subsequently been identified worldwide in various species of the family Enterobacteriaceaemcr-1 encodes a phosphoethanolamine transferase, and its expression has been shown to generate phosphoethanolamine-modified bis-phosphorylated hexa-acylated lipid A in E. coli Here, we investigated the effects of mcr-1 on colistin susceptibility and on lipopolysaccharide structures in laboratory and clinical strains of the Gram-negative ESKAPE (Enterococcus faecium, Staphylococcus aureus, K. pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens, which are often treated clinically by colistin. The effects of mcr-1 on colistin resistance were determined using MIC assays of laboratory and clinical strains of E. coli, K. pneumoniae, A. baumannii, and P. aeruginosa Lipid A structural changes resulting from MCR-1 were analyzed by mass spectrometry. The introduction of mcr-1 led to colistin resistance in E. coli, K. pneumoniae, and A. baumannii but only moderately reduced susceptibility in P. aeruginosa Phosphoethanolamine modification of lipid A was observed consistently for all four species. These findings highlight the risk of colistin resistance as a consequence of mcr-1 expression among ESKAPE pathogens, especially in K. pneumoniae and A. baumannii Furthermore, the observation that lipid A structures were modified despite only modest increases in colistin MICs in some instances suggests more sophisticated surveillance methods may need to be developed to track the dissemination of mcr-1 or plasmid-mediated phosphoethanolamine transferases in general.
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125
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Antibiotic-non-antibiotic combinations for combating extremely drug-resistant Gram-negative 'superbugs'. Essays Biochem 2017; 61:115-125. [PMID: 28258235 DOI: 10.1042/ebc20160058] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/02/2016] [Accepted: 11/03/2016] [Indexed: 12/13/2022]
Abstract
The emergence of antimicrobial resistance of Gram-negative pathogens has become a worldwide crisis. The status quo for combating resistance is to employ synergistic combinations of antibiotics. Faced with this fast-approaching post-antibiotic era, it is critical that we devise strategies to prolong and maximize the clinical efficacy of existing antibiotics. Unfortunately, reports of extremely drug-resistant (XDR) Gram-negative pathogens have become more common. Combining antibiotics such as polymyxin B or the broad-spectrum tetracycline and minocycline with various FDA-approved non-antibiotic drugs have emerged as a novel combination strategy against otherwise untreatable XDR pathogens. This review surveys the available literature on the potential benefits of employing antibiotic-non-antibiotic drug combination therapy. The apex of this review highlights the clinical utility of this novel therapeutic strategy for combating infections caused by 'superbugs'.
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126
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Jeannot K, Bolard A, Plésiat P. Resistance to polymyxins in Gram-negative organisms. Int J Antimicrob Agents 2017; 49:526-535. [PMID: 28163137 DOI: 10.1016/j.ijantimicag.2016.11.029] [Citation(s) in RCA: 255] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/10/2016] [Accepted: 11/25/2016] [Indexed: 12/30/2022]
Abstract
Polymyxins have recently been re-introduced into the therapeutic arsenal to combat infections caused by multidrug-resistant Gram-negative bacteria. However, the emergence of strains resistant to these last-resort drugs is becoming a critical issue in a growing number of countries. Both intrinsic and transferable mechanisms of polymyxin resistance have been characterised. These mechanisms as well as the epidemiological data regarding four relevant bacterial pathogens (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa) are considered in this review. A special focus is made on plasmid-mediated resistance and the spread of mcr genes.
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Affiliation(s)
- Katy Jeannot
- Laboratoire de bactériologie, Centre national de référence (CNR) de la résistance aux antibiotiques, Centre hospitalier universitaire (CHRU) de Besançon, boulevard Fleming, 25000 Besançon, France.
| | - Arnaud Bolard
- Laboratoire de bactériologie, Centre national de référence (CNR) de la résistance aux antibiotiques, Centre hospitalier universitaire (CHRU) de Besançon, boulevard Fleming, 25000 Besançon, France
| | - Patrick Plésiat
- Laboratoire de bactériologie, Centre national de référence (CNR) de la résistance aux antibiotiques, Centre hospitalier universitaire (CHRU) de Besançon, boulevard Fleming, 25000 Besançon, France
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127
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Meneguetti BT, Machado LDS, Oshiro KGN, Nogueira ML, Carvalho CME, Franco OL. Antimicrobial Peptides from Fruits and Their Potential Use as Biotechnological Tools-A Review and Outlook. Front Microbiol 2017; 7:2136. [PMID: 28119671 PMCID: PMC5223440 DOI: 10.3389/fmicb.2016.02136] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/19/2016] [Indexed: 12/20/2022] Open
Abstract
Bacterial resistance is a major threat to plant crops, animals and human health, and over the years this situation has increasingly spread worldwide. Due to their many bioactive compounds, plants are promising sources of antimicrobial compounds that can potentially be used in the treatment of infections caused by microorganisms. As well as stem, flowers and leaves, fruits have an efficient defense mechanism against pests and pathogens, besides presenting nutritional and functional properties due to their multifunctional molecules. Among such compounds, the antimicrobial peptides (AMPs) feature different antimicrobials that are capable of disrupting the microbial membrane and of acting in binding to intra-cytoplasmic targets of microorganisms. They are therefore capable of controlling or halting the growth of microorganisms. In summary, this review describes the major classes of AMPs found in fruits, their possible use as biotechnological tools and prospects for the pharmaceutical industry and agribusiness.
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Affiliation(s)
- Beatriz T Meneguetti
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco Campo Grande, Brazil
| | - Leandro Dos Santos Machado
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco Campo Grande, Brazil
| | - Karen G N Oshiro
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco Campo Grande, Brazil
| | - Micaella L Nogueira
- Graduação em Ciências Biológicas, Universidade Católica Dom Bosco Campo Grande, Brazil
| | - Cristiano M E Carvalho
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom BoscoCampo Grande, Brazil; Graduação em Ciências Biológicas, Universidade Católica Dom BoscoCampo Grande, Brazil
| | - Octávio L Franco
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom BoscoCampo Grande, Brazil; Graduação em Ciências Biológicas, Universidade Católica Dom BoscoCampo Grande, Brazil; Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de BrasíliaBrasília, Brazil
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128
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Kröger C, Kary SC, Schauer K, Cameron ADS. Genetic Regulation of Virulence and Antibiotic Resistance in Acinetobacter baumannii. Genes (Basel) 2016; 8:genes8010012. [PMID: 28036056 PMCID: PMC5295007 DOI: 10.3390/genes8010012] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 12/18/2016] [Accepted: 12/20/2016] [Indexed: 01/14/2023] Open
Abstract
Multidrug resistant microorganisms are forecast to become the single biggest challenge to medical care in the 21st century. Over the last decades, members of the genus Acinetobacter have emerged as bacterial opportunistic pathogens, in particular as challenging nosocomial pathogens because of the rapid evolution of antimicrobial resistances. Although we lack fundamental biological insight into virulence mechanisms, an increasing number of researchers are working to identify virulence factors and to study antibiotic resistance. Here, we review current knowledge regarding the regulation of virulence genes and antibiotic resistance in Acinetobacter baumannii. A survey of the two-component systems AdeRS, BaeSR, GacSA and PmrAB explains how each contributes to antibiotic resistance and virulence gene expression, while BfmRS regulates cell envelope structures important for pathogen persistence. A. baumannii uses the transcription factors Fur and Zur to sense iron or zinc depletion and upregulate genes for metal scavenging as a critical survival tool in an animal host. Quorum sensing, nucleoid-associated proteins, and non-classical transcription factors such as AtfA and small regulatory RNAs are discussed in the context of virulence and antibiotic resistance.
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Affiliation(s)
- Carsten Kröger
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland.
| | - Stefani C Kary
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland.
| | - Kristina Schauer
- Department of Veterinary Science, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Oberschleißheim 85764, Germany.
| | - Andrew D S Cameron
- Department of Biology, University of Regina, Regina, SK S4S 042, Canada.
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129
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Hollaus R, Kosma P, Zamyatina A. Stereoselective Synthesis of α- and β-l-Ara4N Glycosyl H-Phosphonates and a Neoglycoconjugate Comprising Glycosyl Phosphodiester Linked β-l-Ara4N. Org Lett 2016; 19:78-81. [PMID: 28009171 PMCID: PMC5223274 DOI: 10.1021/acs.orglett.6b03358] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
Stereoselective synthesis
of variably protected α- and β-l-Ara4N glycosyl
H-phosphonates as key intermediates in the
syntheses of β-l-Ara4N-modified LPS structures and
α-l-Ara4N-containing biosynthetic precursors is reported.
A facile one-pot approach toward β-l-Ara4N glycosyl
H-phosphonates includes anomeric deallylation of protected 4-azido
β-l-Ara4N via terminal olefin isomerization followed
by ozonolysis and methanolysis of formyl groups to furnish exclusively
β-configured lactols that are phosphitylated with retention
of configuration. The carbohydrate epitope of β-l-Ara4N-modified
Lipid A, βGlcN(1→6)αGlcN(1→P←1)β-l-Ara4N, was stereoselectively synthesized and linked to maleimide-activated
bovine serum albumin.
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Affiliation(s)
- Ralph Hollaus
- Department of Chemistry, University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria
| | - Alla Zamyatina
- Department of Chemistry, University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria
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130
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Abstract
Antimicrobial peptides (AMPs), also known as host defense peptides, are small naturally occurring microbicidal molecules produced by the host innate immune response that function as a first line of defense to kill pathogenic microorganisms by inducing deleterious cell membrane damage. AMPs also possess signaling and chemoattractant activities and can modulate the innate immune response to enhance protective immunity or suppress inflammation. Human pathogens have evolved defense molecules and strategies to counter and survive the AMPs released by host immune cells such as neutrophils and macrophages. Here, we review the various mechanisms used by human bacterial pathogens to resist AMP-mediated killing, including surface charge modification, active efflux, alteration of membrane fluidity, inactivation by proteolytic digestion, and entrapment by surface proteins and polysaccharides. Enhanced understanding of AMP resistance at the molecular level may offer insight into the mechanisms of bacterial pathogenesis and augment the discovery of novel therapeutic targets and drug design for the treatment of recalcitrant multidrug-resistant bacterial infections.
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131
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Gibbons MA, Bowdish DM, Davidson DJ, Sallenave JM, Simpson AJ. Endogenous Pulmonary Antibiotics. Scott Med J 2016; 51:37-42. [PMID: 16722137 DOI: 10.1258/rsmsmj.51.2.37] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The human lung produces a variety of peptides and proteins which have intrinsic antimicrobial activity. In general these molecules have broad spectra of antimicrobial activity, kill micro-organisms rapidly, and evade resistance generated by pathogens. In recent years it has become increasingly apparent that the antimicrobial peptides (AMPs) simultaneously possess immunomodulatory functions, suggesting complex roles for these molecules in regulating the clearance of, and immune response to, invading pathogens. These collective properties have stimulated considerable interest in the potential clinical application of endogenous AMPs. This article outlines the biology of AMPs, their pattern of expression in the lung, and their functions, with reference to both antimicrobial and immunomodulatory activity. We then consider the biological importance of AMPs, before concentrating on the potential to use AMPs to therapeutic effect. The principles discussed in the article apply to innate immune defence throughout the body, but particular emphasis is placed on AMPs in the lung and the potential application to pulmonary infection.
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Affiliation(s)
- M A Gibbons
- Rayne Laboratory, MRC Centre for Inflammation Research, Edinburgh University Medical School, Teviot Place, Edinburgh EH8 9AG, Scotland, UK
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132
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Jochumsen N, Marvig RL, Damkiær S, Jensen RL, Paulander W, Molin S, Jelsbak L, Folkesson A. The evolution of antimicrobial peptide resistance in Pseudomonas aeruginosa is shaped by strong epistatic interactions. Nat Commun 2016; 7:13002. [PMID: 27694971 PMCID: PMC5494192 DOI: 10.1038/ncomms13002] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/24/2016] [Indexed: 11/25/2022] Open
Abstract
Colistin is an antimicrobial peptide that has become the only remaining alternative for the treatment of multidrug-resistant Gram-negative bacterial infections, but little is known of how clinical levels of colistin resistance evolve. We use in vitro experimental evolution and whole-genome sequencing of colistin-resistant Pseudomonas aeruginosa isolates from cystic fibrosis patients to reconstruct the molecular evolutionary pathways open for high-level colistin resistance. We show that the evolution of resistance is a complex, multistep process that requires mutation in at least five independent loci that synergistically create the phenotype. Strong intergenic epistasis limits the number of possible evolutionary pathways to resistance. Mutations in transcriptional regulators are essential for resistance evolution and function as nodes that potentiate further evolution towards higher resistance by functionalizing and increasing the effect of the other mutations. These results add to our understanding of clinical antimicrobial peptide resistance and the prediction of resistance evolution. Colistin is an antibiotic used in the treatment of Pseudomonas aeruginosa infections in cystic fibrosis patients. Here, Jochumsen et al. reconstruct the pathways for the molecular evolution of colistin resistance in P. aeruginosa and show that the number of pathways is highly constrained by interactions among genes.
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Affiliation(s)
- Nicholas Jochumsen
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Rasmus L Marvig
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark.,Center for Genomic Medicine, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Søren Damkiær
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Rune Lyngklip Jensen
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Wilhelm Paulander
- Department of Veterinary Disease Biology, University of Copenhagen, 1870 Frederiksberg C, Denmark
| | - Søren Molin
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Lars Jelsbak
- Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Anders Folkesson
- National Veterinary Institute, Technical University of Denmark, Frederiksberg, Denmark
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133
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Trent MS, Stead CM, Tran AX, Hankins JV. Invited review: Diversity of endotoxin and its impact on pathogenesis. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519060120040201] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Lipopolysaccharide or LPS is localized to the outer leaflet of the outer membrane and serves as the major surface component of the bacterial cell envelope. This remarkable glycolipid is essential for virtually all Gram-negative organisms and represents one of the conserved microbial structures responsible for activation of the innate immune system. For these reasons, the structure, function, and biosynthesis of LPS has been an area of intense research. The LPS of a number of bacteria is composed of three distinct regions — lipid A, a short core oligosaccharide, and the O-antigen polysaccharide. The lipid A domain, also known as endotoxin, anchors the molecule in the outer membrane and is the bioactive component recognized by TLR4 during human infection. Overall, the biochemical synthesis of lipid A is a highly conserved process; however, investigation of the lipid A structures of various organisms shows an impressive amount of diversity. These differences can be attributed to the action of latent enzymes that modify the canonical lipid A molecule. Variation of the lipid A domain of LPS serves as one strategy utilized by Gram-negative bacteria to promote survival by providing resistance to components of the innate immune system and helping to evade recognition by TLR4. This review summarizes the biochemical machinery required for the production of diverse lipid A structures of human pathogens and how structural modification of endotoxin impacts pathogenesis.
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Affiliation(s)
- M. Stephen Trent
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA,
| | - Christopher M. Stead
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - An X. Tran
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Jessica V. Hankins
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
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134
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Review: Conserved and variable structural features in the lipopolysaccharide of Pseudomonas aeruginosa. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519060120060201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The review is devoted to recent progress in the structural elucidation of the lipopolysaccharide of the bacterium Pseudomonas aeruginosa, including O-antigen biological repeats, core oligosaccharide, and lipid A. Data on biosynthesis, genetics and serology of the lipopolysaccharide isolated from various P. aeruginosa O-serogroups are discussed in relation to the chemical structures.
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135
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Liebens V, Frangipani E, Van der Leyden A, Fauvart M, Visca P, Michiels J. Membrane localization and topology of the DnpA protein control fluoroquinolone tolerance in Pseudomonas aeruginosa. FEMS Microbiol Lett 2016; 363:fnw184. [PMID: 27481702 DOI: 10.1093/femsle/fnw184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2016] [Indexed: 12/31/2022] Open
Abstract
DnpA, a putative de-N-acetylase of the PIG-L superfamily, is required for antibiotic tolerance in Pseudomonas aeruginosa Exactly how dnpA (gene locus PA5002) directs the formation of antibiotic-tolerant persister cells is currently unknown. Previous research provided evidence for a role in surface-associated process(es), possibly in lipopolysaccharide biosynthesis. In silico sequence analysis of DnpA predicts a single transmembrane domain and Nin/Cout orientation of DnpA. In contrast, we here show that DnpA is an integral inner membrane protein containing two transmembrane domains, with the major C-terminal part located at the cytoplasmic face. Correct insertion into the inner membrane is necessary for DnpA to promote fluoroquinolone tolerance. The membrane localization of DnpA further supports its role in cell envelope-associated process(es). In addition to shedding light on the biological role of DnpA, this study highlights the risks of overreliance on the predictive value of bioinformatics tools and the importance of rigorous experimental validation of in silico predictions.
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Affiliation(s)
- Veerle Liebens
- Centre of Microbial and Plant Genetics, KU Leuven, 3001 Leuven, Belgium
| | | | | | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven, 3001 Leuven, Belgium imec, Smart Systems and Emerging Technologies Unit, Department of Life Science Technologies, 3001 Leuven, Belgium
| | - Paolo Visca
- Department of Sciences, Roma Tre University, Rome 00146, Italy
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, 3001 Leuven, Belgium
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136
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Charretier Y, Schrenzel J. Mass spectrometry methods for predicting antibiotic resistance. Proteomics Clin Appl 2016; 10:964-981. [PMID: 27312049 DOI: 10.1002/prca.201600041] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/09/2016] [Accepted: 06/13/2016] [Indexed: 11/10/2022]
Abstract
Developing elaborate techniques for clinical applications can be a complicated process. Whole-cell MALDI-TOF MS revolutionized reliable microorganism identification in clinical microbiology laboratories and is now replacing phenotypic microbial identification. This technique is a generic, accurate, rapid, and cost-effective growth-based method. Antibiotic resistance keeps emerging in environmental and clinical microorganisms, leading to clinical therapeutic challenges, especially for Gram-negative bacteria. Antimicrobial susceptibility testing is used to reliably predict antimicrobial success in treating infection, but it is inherently limited by the need to isolate and grow cultures, delaying the application of appropriate therapies. Antibiotic resistance prediction by growth-independent methods is expected to reduce the turnaround time. Recently, the potential of next-generation sequencing and microarrays in predicting microbial resistance has been demonstrated, and this review evaluates the potential of MS in this field. First, technological advances are described, and the possibility of predicting antibiotic resistance by MS is then illustrated for three prototypical human pathogens: Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Clearly, MS methods can identify antimicrobial resistance mediated by horizontal gene transfers or by mutations that affect the quantity of a gene product, whereas antimicrobial resistance mediated by target mutations remains difficult to detect.
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Affiliation(s)
- Yannick Charretier
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals.
| | - Jacques Schrenzel
- Genomic Research Laboratory, Division of Infectious Diseases, Geneva University Hospitals
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137
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Maldonado RF, Sá-Correia I, Valvano MA. Lipopolysaccharide modification in Gram-negative bacteria during chronic infection. FEMS Microbiol Rev 2016; 40:480-93. [PMID: 27075488 PMCID: PMC4931227 DOI: 10.1093/femsre/fuw007] [Citation(s) in RCA: 372] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/23/2015] [Accepted: 03/10/2016] [Indexed: 12/16/2022] Open
Abstract
The Gram-negative bacterial lipopolysaccharide (LPS) is a major component of the outer membrane that plays a key role in host-pathogen interactions with the innate immune system. During infection, bacteria are exposed to a host environment that is typically dominated by inflammatory cells and soluble factors, including antibiotics, which provide cues about regulation of gene expression. Bacterial adaptive changes including modulation of LPS synthesis and structure are a conserved theme in infections, irrespective of the type or bacteria or the site of infection. In general, these changes result in immune system evasion, persisting inflammation and increased antimicrobial resistance. Here, we review the modifications of LPS structure and biosynthetic pathways that occur upon adaptation of model opportunistic pathogens (Pseudomonas aeruginosa, Burkholderia cepacia complex bacteria, Helicobacter pylori and Salmonella enterica) to chronic infection in respiratory and gastrointestinal sites. We also discuss the molecular mechanisms of these variations and their role in the host-pathogen interaction.
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Affiliation(s)
- Rita F. Maldonado
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal
| | - Isabel Sá-Correia
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal
| | - Miguel A. Valvano
- Department of Microbiology and Immunology, University of Western Ontario, London, ON N6A 5C1, Canada
- Centre for Infection and Immunity, Queen's University Belfast, Belfast BT9 7BL, UK
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138
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Rashid R, Veleba M, Kline KA. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides. Front Cell Dev Biol 2016; 4:55. [PMID: 27376064 PMCID: PMC4894902 DOI: 10.3389/fcell.2016.00055] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/23/2016] [Indexed: 01/15/2023] Open
Abstract
Antimicrobial peptides (AMPs) are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs) target anionic lipids [e.g., phosphatidylglycerol (PG) and cardiolipins (CL)] in the cell membrane and anionic components [e.g., lipopolysaccharide (LPS) and lipoteichoic acid (LTA)] of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g., lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1) CAMP disruption mechanisms, (2) delocalization of membrane proteins and lipids by CAMPs, and (3) CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging, and non-detergent-based membrane domain extraction.
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Affiliation(s)
- Rafi Rashid
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University Singapore, Singapore
| | - Mark Veleba
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University Singapore, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University Singapore, Singapore
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139
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Abstract
Polymyxins have emerged as an important last-line of defense against Gram-negative ‘superbugs’. Unfortunately, the effective use of polymyxins in the clinic has been hampered by their nephrotoxic side effects. Over the last 10 years various industry and academic groups across the globe have been trying to develop new polymyxins that are safer and more efficacious than the currently approved polymyxin B and colistin. However these drug discovery programs are yet to deliver a new and improved polymyxin drug into the clinic. In this piece we provide an overview of the current state of these polymyxin drug discovery programs from a medicinal chemistry perspective as well as some thoughts on how future drug discovery efforts may ultimately find success.
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140
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Morphological and functional adaptations of Fusobacterium nucleatum exposed to human neutrophil Peptide-1. Anaerobe 2016; 39:31-8. [DOI: 10.1016/j.anaerobe.2016.02.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 11/21/2022]
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141
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150292. [PMID: 27160595 PMCID: PMC4874390 DOI: 10.1098/rstb.2015.0292] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2016] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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142
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Joo HS, Fu CI, Otto M. Bacterial strategies of resistance to antimicrobial peptides. Philos Trans R Soc Lond B Biol Sci 2016. [PMID: 27160595 DOI: 10.1098/rstb.2015.0292.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Hwang-Soo Joo
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Chih-Iung Fu
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
| | - Michael Otto
- Pathogen Molecular Genetics Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases (NIAID), US National Institutes of Health (NIH), 50 South Drive, Bethesda, MD 20892, USA
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143
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Evolved resistance to colistin and its loss due to genetic reversion in Pseudomonas aeruginosa. Sci Rep 2016; 6:25543. [PMID: 27150578 PMCID: PMC4858706 DOI: 10.1038/srep25543] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 04/20/2016] [Indexed: 11/17/2022] Open
Abstract
The increased reliance on colistin for treating multidrug-resistant Gram-negative bacterial infections has resulted in the emergence of colistin-resistant Pseudomonas aeruginosa. We attempted to identify genetic contributors to colistin resistance in vitro evolved isogenic colistin-resistant and -susceptible strains of two P. aeruginosa lineages (P5 and P155). Their evolutionary paths to acquisition and loss of colistin resistance were also tracked. Comparative genomic analysis revealed 13 and five colistin resistance determinants in the P5 and P155 lineages, respectively. Lipid A in colistin-resistant mutants was modified through the addition of 4-amino-L-arabinose; this modification was absent in colistin-susceptible revertant strains. Many amino acid substitutions that emerged during the acquisition of colistin resistance were reversed in colistin-susceptible revertants. We demonstrated that evolved colistin resistance in P. aeruginosa was mediated by a complicated regulatory network that likely emerges through diverse genetic alterations. Colistin-resistant P. aeruginosa became susceptible to the colistin upon its withdrawal because of genetic reversion. The mechanisms through which P. aeruginosa acquires and loses colistin resistance have implications on the treatment options that can be applied against P. aeruginosa infections, with respect to improving bactericidal efficacy and preventing further resistance to antibiotics.
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144
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145
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Abstract
Cationic antimicrobial peptides (CAMPs) are important innate immune defenses that inhibit colonization by pathogens and contribute to clearance of infections. Gram-negative bacterial pathogens are a major target, yet many of them have evolved mechanisms to resist these antimicrobials. These resistance mechanisms can be critical contributors to bacterial virulence and are often crucial for survival within the host. Here, we summarize methods used by Gram-negative bacteria to resist CAMPs. Understanding these mechanisms may lead to new therapeutic strategies against pathogens with extensive CAMP resistance.
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Affiliation(s)
- Victor I. Band
- Department of Microbiology and Immunology, Emory University, Atlanta, GA 30329, USA; E-Mail:
- Yerkes Primate Research Center, Emory University, Atlanta, GA 30329, USA
- Emory Vaccine Center, Emory University, Atlanta, GA 30329, USA
| | - David S. Weiss
- Yerkes Primate Research Center, Emory University, Atlanta, GA 30329, USA
- Emory Vaccine Center, Emory University, Atlanta, GA 30329, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30329, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-404-727-8214; Fax: +1-404-727-8199
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146
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The Pseudomonas aeruginosa PAO1 Two-Component Regulator CarSR Regulates Calcium Homeostasis and Calcium-Induced Virulence Factor Production through Its Regulatory Targets CarO and CarP. J Bacteriol 2016; 198:951-63. [PMID: 26755627 DOI: 10.1128/jb.00963-15] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 12/31/2015] [Indexed: 02/02/2023] Open
Abstract
UNLABELLED Pseudomonas aeruginosa is an opportunistic human pathogen that causes severe, life-threatening infections in patients with cystic fibrosis (CF), endocarditis, wounds, or artificial implants. During CF pulmonary infections, P. aeruginosa often encounters environments where the levels of calcium (Ca(2+)) are elevated. Previously, we showed that P. aeruginosa responds to externally added Ca(2+) through enhanced biofilm formation, increased production of several secreted virulence factors, and by developing a transient increase in the intracellular Ca(2+) level, followed by its removal to the basal submicromolar level. However, the molecular mechanisms responsible for regulating Ca(2+)-induced virulence factor production and Ca(2+) homeostasis are not known. Here, we characterized the genome-wide transcriptional response of P. aeruginosa to elevated [Ca(2+)] in both planktonic cultures and biofilms. Among the genes induced by CaCl2 in strain PAO1 was an operon containing the two-component regulator PA2656-PA2657 (here called carS and carR), while the closely related two-component regulators phoPQ and pmrAB were repressed by CaCl2 addition. To identify the regulatory targets of CarSR, we constructed a deletion mutant of carR and performed transcriptome analysis of the mutant strain at low and high [Ca(2+)]. Among the genes regulated by CarSR in response to CaCl2 are the predicted periplasmic OB-fold protein, PA0320 (here called carO), and the inner membrane-anchored five-bladed β-propeller protein, PA0327 (here called carP). Mutations in both carO and carP affected Ca(2+) homeostasis, reducing the ability of P. aeruginosa to export excess Ca(2+). In addition, a mutation in carP had a pleotropic effect in a Ca(2+)-dependent manner, altering swarming motility, pyocyanin production, and tobramycin sensitivity. Overall, the results indicate that the two-component system CarSR is responsible for sensing high levels of external Ca(2+) and responding through its regulatory targets that modulate Ca(2+) homeostasis, surface-associated motility, and the production of the virulence factor pyocyanin. IMPORTANCE During infectious disease, Pseudomonas aeruginosa encounters environments with high calcium (Ca(2+)) concentrations, yet the cells maintain intracellular Ca(2+) at levels that are orders of magnitude less than that of the external environment. In addition, Ca(2+) signals P. aeruginosa to induce the production of several virulence factors. Compared to eukaryotes, little is known about how bacteria maintain Ca(2+) homeostasis or how Ca(2+) acts as a signal. In this study, we identified a two-component regulatory system in P. aeruginosa PAO1, termed CarRS, that is induced at elevated Ca(2+) levels. CarRS modulates Ca(2+) signaling and Ca(2+) homeostasis through its regulatory targets, CarO and CarP. The results demonstrate that P. aeruginosa uses a two-component regulatory system to sense external Ca(2+) and relays that information for Ca(2+)-dependent cellular processes.
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147
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Steinbuch KB, Fridman M. Mechanisms of resistance to membrane-disrupting antibiotics in Gram-positive and Gram-negative bacteria. MEDCHEMCOMM 2016. [DOI: 10.1039/c5md00389j] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A diverse repertoire of mechanisms has evolved to confer resistance to bacterial membrane disrupting antimicrobial cationic amphiphiles.
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Affiliation(s)
- Kfir B. Steinbuch
- School of Chemistry
- Beverly Raymond Sackler Faculty of Exact Sciences
- Tel Aviv University
- Tel Aviv
- Israel
| | - Micha Fridman
- School of Chemistry
- Beverly Raymond Sackler Faculty of Exact Sciences
- Tel Aviv University
- Tel Aviv
- Israel
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148
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Extracellular DNA Acidifies Biofilms and Induces Aminoglycoside Resistance in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2015; 60:544-53. [PMID: 26552982 DOI: 10.1128/aac.01650-15] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Biofilms consist of surface-adhered bacterial communities encased in an extracellular matrix composed of DNA, exopolysaccharides, and proteins. Extracellular DNA (eDNA) has a structural role in the formation of biofilms, can bind and shield biofilms from aminoglycosides, and induces antimicrobial peptide resistance mechanisms. Here, we provide evidence that eDNA is responsible for the acidification of Pseudomonas aeruginosa planktonic cultures and biofilms. Further, we show that acidic pH and acidification via eDNA constitute a signal that is perceived by P. aeruginosa to induce the expression of genes regulated by the PhoPQ and PmrAB two-component regulatory systems. Planktonic P. aeruginosa cultured in exogenous 0.2% DNA or under acidic conditions demonstrates a 2- to 8-fold increase in aminoglycoside resistance. This resistance phenotype requires the aminoarabinose modification of lipid A and the production of spermidine on the bacterial outer membrane, which likely reduce the entry of aminoglycosides. Interestingly, the additions of the basic amino acid L-arginine and sodium bicarbonate neutralize the pH and restore P. aeruginosa susceptibility to aminoglycosides, even in the presence of eDNA. These data illustrate that the accumulation of eDNA in biofilms and infection sites can acidify the local environment and that acidic pH promotes the P. aeruginosa antibiotic resistance phenotype.
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149
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Rodríguez-Rojas A, Makarova O, Müller U, Rolff J. Cationic Peptides Facilitate Iron-induced Mutagenesis in Bacteria. PLoS Genet 2015; 11:e1005546. [PMID: 26430769 PMCID: PMC4592263 DOI: 10.1371/journal.pgen.1005546] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/01/2015] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa is the causative agent of chronic respiratory infections and is an important pathogen of cystic fibrosis patients. Adaptive mutations play an essential role for antimicrobial resistance and persistence. The factors that contribute to bacterial mutagenesis in this environment are not clear. Recently it has been proposed that cationic antimicrobial peptides such as LL-37 could act as mutagens in P. aeruginosa. Here we provide experimental evidence that mutagenesis is the product of a joint action of LL-37 and free iron. By estimating mutation rate, mutant frequencies and assessing mutational spectra in P. aeruginosa treated either with LL-37, iron or a combination of both we demonstrate that mutation rate and mutant frequency were increased only when free iron and LL-37 were present simultaneously. Colistin had the same effect. The addition of an iron chelator completely abolished this mutagenic effect, suggesting that LL-37 enables iron to enter the cells resulting in DNA damage by Fenton reactions. This was also supported by the observation that the mutational spectrum of the bacteria under LL-37-iron regime showed one of the characteristic Fenton reaction fingerprints: C to T transitions. Free iron concentration in nature and within hosts is kept at a very low level, but the situation in infected lungs of cystic fibrosis patients is different. Intermittent bleeding and damage to the epithelial cells in lungs may contribute to the release of free iron that in turn leads to generation of reactive oxygen species and deterioration of the respiratory tract, making it more susceptible to the infection.
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Affiliation(s)
- Alexandro Rodríguez-Rojas
- Evolutionary Biology, Institute for Biology, Free University Berlin, Berlin, Germany
- * E-mail: (ARR); (JR)
| | - Olga Makarova
- Evolutionary Biology, Institute for Biology, Free University Berlin, Berlin, Germany
| | - Uta Müller
- Evolutionary Biology, Institute for Biology, Free University Berlin, Berlin, Germany
| | - Jens Rolff
- Evolutionary Biology, Institute for Biology, Free University Berlin, Berlin, Germany
- * E-mail: (ARR); (JR)
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150
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Polymyxin Susceptibility in Pseudomonas aeruginosa Linked to the MexXY-OprM Multidrug Efflux System. Antimicrob Agents Chemother 2015; 59:7276-89. [PMID: 26369970 DOI: 10.1128/aac.01785-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/04/2015] [Indexed: 12/21/2022] Open
Abstract
The ribosome-targeting antimicrobial, spectinomycin (SPC), strongly induced the mexXY genes of the MexXY-OprM multidrug efflux system in Pseudomonas aeruginosa and increased susceptibility to the polycationic antimicrobials polymyxin B and polymyxin E, concomitant with a decrease in expression of the polymyxin resistance-promoting lipopolysaccharide (LPS) modification loci, arnBCADTEF and PA4773-74. Consistent with the SPC-promoted reduction in arn and PA4773-74 expression being linked to mexXY, expression of these LPS modification loci was moderated in a mutant constitutively expressing mexXY and enhanced in a mutant lacking the efflux genes. Still, the SPC-mediated increase in polymyxin susceptibility was retained in mutants lacking arnB and/or PA4773-74, an indication that their reduced expression in SPC-treated cells does not explain the enhanced polymyxin susceptibility. That the polymyxin susceptibility of a mutant strain lacking mexXY was unaffected by SPC exposure, however, was an indication that the unknown polymyxin resistance 'mechanism' is also influenced by the MexXY status of the cell. In agreement with SPC and MexXY influencing polymyxin susceptibility as a result of changes in the LPS target of these agents, SPC treatment yielded a decline in common polysaccharide antigen (CPA) synthesis in wild-type P. aeruginosa but not in the ΔmexXY mutant. A mutant lacking CPA still showed the SPC-mediated decline in polymyxin MICs, however, indicating that the loss of CPA did not explain the SPC-mediated MexXY-dependent increase in polymyxin susceptibility. It is possible, therefore, that some additional change in LPS promoted by SPC-induced mexXY expression impacted CPA synthesis or its incorporation into LPS and that this was responsible for the observed changes in polymyxin susceptibility.
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