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Djonović S, Urbach JM, Drenkard E, Bush J, Feinbaum R, Ausubel JL, Traficante D, Risech M, Kocks C, Fischbach MA, Priebe GP, Ausubel FM. Trehalose biosynthesis promotes Pseudomonas aeruginosa pathogenicity in plants. PLoS Pathog 2013; 9:e1003217. [PMID: 23505373 PMCID: PMC3591346 DOI: 10.1371/journal.ppat.1003217] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 01/13/2013] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa strain PA14 is a multi-host pathogen that infects plants, nematodes, insects, and vertebrates. Many PA14 factors are required for virulence in more than one of these hosts. Noting that plants have a fundamentally different cellular architecture from animals, we sought to identify PA14 factors that are specifically required for plant pathogenesis. We show that synthesis by PA14 of the disaccharide trehalose is required for pathogenesis in Arabidopsis, but not in nematodes, insects, or mice. In-frame deletion of two closely-linked predicted trehalose biosynthetic operons, treYZ and treS, decreased growth in Arabidopsis leaves about 50 fold. Exogenously co-inoculated trehalose, ammonium, or nitrate, but not glucose, sulfate, or phosphate suppressed the phenotype of the double ΔtreYZΔtreS mutant. Exogenous trehalose or ammonium nitrate does not suppress the growth defect of the double ΔtreYZΔtreS mutant by suppressing the plant defense response. Trehalose also does not function intracellularly in P. aeruginosa to ameliorate a variety of stresses, but most likely functions extracellularly, because wild-type PA14 rescued the in vivo growth defect of the ΔtreYZΔtreS in trans. Surprisingly, the growth defect of the double ΔtreYZΔtreS double mutant was suppressed by various Arabidopsis cell wall mutants that affect xyloglucan synthesis, including an xxt1xxt2 double mutant that completely lacks xyloglucan, even though xyloglucan mutants are not more susceptible to pathogens and respond like wild-type plants to immune elicitors. An explanation of our data is that trehalose functions to promote the acquisition of nitrogen-containing nutrients in a process that involves the xyloglucan component of the plant cell wall, thereby allowing P. aeruginosa to replicate in the intercellular spaces in a leaf. This work shows how P. aeruginosa, a multi-host opportunistic pathogen, has repurposed a highly conserved "house-keeping" anabolic pathway (trehalose biosynthesis) as a potent virulence factor that allows it to replicate in the intercellular environment of a leaf.
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Affiliation(s)
- Slavica Djonović
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jonathan M. Urbach
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Eliana Drenkard
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jenifer Bush
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Rhonda Feinbaum
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jonathan L. Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - David Traficante
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Martina Risech
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Christine Kocks
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael A. Fischbach
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States of America
| | - Gregory P. Priebe
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
- Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts, United States of America
| | - Frederick M. Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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152
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Lechner S, Patra P, Klumpp S, Bertram R. Interplay between population dynamics and drug tolerance of Staphylococcus aureus persister cells. J Mol Microbiol Biotechnol 2013; 22:381-91. [PMID: 23363876 DOI: 10.1159/000346073] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Population dynamics parameters of Staphylococcus aureus strain SA113 were quantified based on growth and killing experiments with batch culture cells in rich medium. Eradication kinetics and the concomitant isolation of a subpopulation of drug-tolerant SA113 persisters upon treatment with super-minimal inhibitory concentrations of antibiotics such as ciprofloxacin, daptomycin, and tobramycin served as a basis for mathematical analyses. According to a two-state model for stochastic phenotype switching, levels of persister cells and their eradication rates were influenced by the antibiotics used for isolation, clearly indicating a heterogeneous pool of S. aureus persisters. Judging from time-dependent experiments, the persisters' degree of drug tolerance correlated with the duration of antibiotic challenge. Moreover, cross-tolerance experiments with cells consecutively treated with two different antibiotics revealed that multi-drug tolerance is not a necessary trait of S. aureus persisters isolated by antibiotic challenge. In some cases, the results depended on the order of the two antibiotic treatments, suggesting that antibiotic tolerance may be achieved by a combination of preexisting persisters and an adaptive response to drug exposure. Counts of live cells which had endured drug treatment increased only after lag phases of at least 3 h after the shift to non-selective conditions. Thus, this study provides quantitative insights into population dynamics of S. aureus persisters with regard to antibiotic challenge.
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Affiliation(s)
- Sabrina Lechner
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin, Lehrbereich Mikrobielle Genetik, Eberhard Karls Universität Tübingen, Tübingen, Germany
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153
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New-found fundamentals of bacterial persistence. Trends Microbiol 2012; 20:577-85. [DOI: 10.1016/j.tim.2012.08.009] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/10/2012] [Accepted: 08/17/2012] [Indexed: 12/26/2022]
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154
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Niepa TH, Gilbert JL, Ren D. Controlling Pseudomonas aeruginosa persister cells by weak electrochemical currents and synergistic effects with tobramycin. Biomaterials 2012; 33:7356-65. [DOI: 10.1016/j.biomaterials.2012.06.092] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 06/29/2012] [Indexed: 11/27/2022]
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155
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Dufour D, Leung V, Lévesque CM. Bacterial biofilm: structure, function, and antimicrobial resistance. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1601-1546.2012.00277.x] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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156
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Pan J, Bahar AA, Syed H, Ren D. Reverting antibiotic tolerance of Pseudomonas aeruginosa PAO1 persister cells by (Z)-4-bromo-5-(bromomethylene)-3-methylfuran-2(5H)-one. PLoS One 2012; 7:e45778. [PMID: 23029239 PMCID: PMC3447867 DOI: 10.1371/journal.pone.0045778] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 08/24/2012] [Indexed: 01/23/2023] Open
Abstract
Background Bacteria are well known to form dormant persister cells that are tolerant to most antibiotics. Such intrinsic tolerance also facilitates the development of multidrug resistance through acquired mechanisms. Thus persister cells are a promising target for developing more effective methods to control chronic infections and help prevent the development of multidrug-resistant bacteria. However, control of persister cells is still an unmet challenge. Methodology/Principal Findings We show in this report that (Z)-4-bromo-5-(bromomethylene)-3-methylfuran-2(5H)-one (BF8) can restore the antibiotic susceptibility of Pseudomonas aeruginosa PAO1 persister cells at growth non-inhibitory concentrations. Persister control by BF8 was found to be effective against both planktonic and biofilm cells of P. aeruginosa PAO1. Interestingly, although BF8 is an inhibitor of quorum sensing (QS) in Gram-negative bacteria, the data in this study suggest that the activities of BF8 to revert antibiotic tolerance of P. aeruginosa PAO1 persister cells is not through QS inhibition and may involve other targets. Conclusion BF8 can sensitize P. aeruginosa persister cells to antibiotics.
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Affiliation(s)
- Jiachuan Pan
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
- Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York, United States of America
| | - Ali Adem Bahar
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
- Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York, United States of America
| | - Haseeba Syed
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
- Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York, United States of America
| | - Dacheng Ren
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States of America
- Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York, United States of America
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, New York, United States of America
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
- * E-mail:
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157
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Jubair M, Morris JG, Ali A. Survival of Vibrio cholerae in nutrient-poor environments is associated with a novel "persister" phenotype. PLoS One 2012; 7:e45187. [PMID: 23028836 PMCID: PMC3445476 DOI: 10.1371/journal.pone.0045187] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 08/16/2012] [Indexed: 12/14/2022] Open
Abstract
In response to antibiotic and/or environmental stress, some species of bacteria shift to a “persister” phenotype. Although toxigenic Vibrio cholerae, responsible for the disease cholera, can be found in nutrient-poor aquatic environments in endemic areas, the underlying mechanism(s) by which culturable cells persist in these environmental reservoirs is largely unknown. Here we report that introduction of V. cholerae into a nutrient-poor filter sterilized lake water (FSLW) microcosm promoted a shift to what we have defined as a “persister” phenotype (PP) which was culturable for >700 days. Direct transfer of PP of V. cholerae from original microcosms to freshly prepared FSLW resulted in the same pattern of persistence seen in the original microcosms. Scanning electron microscopy of cells persisting for over 700 days demonstrated cell morphologies that were very small in size, with a high degree of aggregation associated with flagella emanating from all aspects of the cell. V. cholerae PP cells reverted to a typical V. cholerae morphology when transferred to nutrient-rich L- broth. Cell-free supernatants obtained from microcosms at 24 hours, 180 days, and 700 days all showed >2-fold increase in CAI-1 signaling molecules, consistent with quorum sensing activity, as has been described for Pseudomonas aeruginosa persister cells. Chitin and phosphate promoted cell growth. Our data suggest that nutrient stress can select a V. cholerae persister phenotype in environmental reservoirs, with these strains then seeding subsequent cholera epidemics in response to chitin and phosphate availability.
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Affiliation(s)
- Mohamma Jubair
- Department of Environmental and Global Health, School of Public Health and Health Profession, University of Florida at Gainesville, Gainesville, Florida
| | - J. Glenn Morris
- Emerging Pathogens Institute, University of Florida at Gainesville, Gainesville, Florida
| | - Afsar Ali
- Department of Environmental and Global Health, School of Public Health and Health Profession, University of Florida at Gainesville, Gainesville, Florida
- Emerging Pathogens Institute, University of Florida at Gainesville, Gainesville, Florida
- * E-mail:
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158
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Lechner S, Lewis K, Bertram R. Staphylococcus aureus persisters tolerant to bactericidal antibiotics. J Mol Microbiol Biotechnol 2012; 22:235-44. [PMID: 22986269 DOI: 10.1159/000342449] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Bacterial persister cells are non- or slow-growing reversible phenotypic variants of the wild type, tolerant to bactericidal antibiotics. We analyzed here Staphylococcus aureus persister levels by monitoring colony-forming unit counts of planktonically grown cells treated with six different antimicrobials over time. The model laboratory strains HG001-HG003, SA113 and the small colony variant (SCV) strains hemB and menD were challenged by the compounds at different logs of minimal inhibitory concentration (MIC) in exponential or stationary growth phase. Antibiotic tolerance was usually elevated in SCV strains compared to normally growing cells and in stationary versus exponential phase cultures. Biphasic killing kinetics, typical for persister cell enrichment, were observed in both growth phases under different selective conditions. Treatment of exponential phase cultures of HG001-HG003 with 10-fold MIC of tobramycin resulted in the isolation of persisters which upon cultivation on plates formed either normal or phenotypically stable small colonies. Trajectories of different killing curves indicated physiological heterogeneity within persister subpopulations. Daptomycin added at 100-fold MIC to stationary phase SA113 cells rapidly isolated very robust persisters. Fractions of antibiotic-tolerant cells were observed with all S. aureus strains and mutants tested. Our results refute the hypothesis that S. aureus stationary phase cells are equivalent to persisters, as not all of these cells showed antibiotic tolerance. Isolation of S. aureus persisters of different robustness seems to depend on the kind and concentration of the antibiotic, as well as on the strain used.
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Affiliation(s)
- Sabrina Lechner
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin, Lehrbereich Mikrobielle Genetik, Eberhard Karls Universität Tübingen, Tübingen, Germany
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159
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Gabani P, Prakash D, Singh OV. Emergence of antibiotic-resistant extremophiles (AREs). Extremophiles 2012; 16:697-713. [PMID: 22907125 DOI: 10.1007/s00792-012-0475-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 08/02/2012] [Indexed: 12/14/2022]
Abstract
Excessive use of antibiotics in recent years has produced bacteria that are resistant to a wide array of antibiotics. Several genetic and non-genetic elements allow microorganisms to adapt and thrive under harsh environmental conditions such as lethal doses of antibiotics. We attempt to classify these microorganisms as antibiotic-resistant extremophiles (AREs). AREs develop strategies to gain greater resistance to antibiotics via accumulation of multiple genes or plasmids that harbor genes for multiple drug resistance (MDR). In addition to their altered expression of multiple genes, AREs also survive by producing enzymes such as penicillinase that inactivate antibiotics. It is of interest to identify the underlying molecular mechanisms by which the AREs are able to survive in the presence of wide arrays of high-dosage antibiotics. Technologically, "omics"-based approaches such as genomics have revealed a wide array of genes differentially expressed in AREs. Proteomics studies with 2DE, MALDI-TOF, and MS/MS have identified specific proteins, enzymes, and pumps that function in the adaptation mechanisms of AREs. This article discusses the molecular mechanisms by which microorganisms develop into AREs and how "omics" approaches can identify the genetic elements of these adaptation mechanisms. These objectives will assist the development of strategies and potential therapeutics to treat outbreaks of pathogenic microorganisms in the future.
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Affiliation(s)
- Prashant Gabani
- Division of Biological and Health Sciences, University of Pittsburgh, 300 Campus Drive, Bradford, PA 16701, USA
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160
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Rogers GB, Carroll MP, Bruce KD. Enhancing the utility of existing antibiotics by targeting bacterial behaviour? Br J Pharmacol 2012; 165:845-57. [PMID: 21864314 DOI: 10.1111/j.1476-5381.2011.01643.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The discovery of novel classes of antibiotics has slowed dramatically. This has occurred during a time when the appearance of resistant strains of bacteria has shown a substantial increase. Concern is therefore mounting over our ability to continue to treat infections in an effective manner using the antibiotics that are currently available. While ongoing efforts to discover new antibiotics are important, these must be coupled with strategies that aim to maintain as far as possible the spectrum of activity of existing antibiotics. In many instances, the resistance to antibiotics exhibited by bacteria in chronic infections is mediated not by direct resistance mechanisms, but by the adoption of modes of growth that confer reduced susceptibility. These include the formation of biofilms and the occurrence of subpopulations of 'persister' cells. As our understanding of these processes has increased, a number of new potential drug targets have been revealed. Here, advances in our ability to disrupt these systems that confer reduced susceptibility, and in turn increase the efficacy of antibiotic therapy, are discussed.
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Affiliation(s)
- Geraint B Rogers
- Molecular Microbiology Research Laboratory, Institute of Pharmaceutical Sciences, King's College London, London, UK.
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161
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A stress-inducible quorum-sensing peptide mediates the formation of persister cells with noninherited multidrug tolerance. J Bacteriol 2012; 194:2265-74. [PMID: 22366415 DOI: 10.1128/jb.06707-11] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Within a given microbial population, a small subpopulation known as dormant persister cells exists. This persistence property ensures the survival of the population as a whole in the presence of lethal factors. Although persisters are highly important in antibiotic therapy, the mechanism for persistence is still not thoroughly understood. We show here that the cariogenic organism Streptococcus mutans forms persister cells showing noninherited multidrug tolerance. We demonstrated that the ectopic expression of the type II toxin-antitoxin systems, MazEF and RelBE, caused an increase in the number of persisters. In a search for additional persistence genes, an expression library was constructed, and several clones exhibiting a significant difference in persister formation after prolonged antibiotic treatment were selected. The candidate persister genes include genes involved in transcription/replication, sugar metabolism, cell wall synthesis, and energy metabolism, clearly pointing to redundant pathways for persister formation. We have previously reported that the S. mutans quorum-sensing peptide, CSP pheromone, was a stress-inducible alarmone capable of conveying sophisticated messages in the bacterial population. In this study, we demonstrate the involvement of the intraspecies quorum-sensing system during the formation of stress-induced multidrug-tolerant persisters. To the best of our knowledge, this is the first study reporting the induction of bacterial persistence using a quorum-sensing regulatory system.
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162
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RelE-mediated dormancy is enhanced at high cell density in Escherichia coli. J Bacteriol 2011; 194:1169-76. [PMID: 22210768 DOI: 10.1128/jb.06628-11] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria show remarkable adaptability under several stressful conditions by shifting themselves into a dormant state. Less is known, however, about the mechanism underlying the cell transition to dormancy. Here, we report that the transition to dormant states is mediated by one of the major toxin-antitoxin systems, RelEB, in a cell density-dependent manner in Escherichia coli K-12 MG1655. We constructed a strain, IKA121, which expresses the toxin RelE in the presence of rhamnose and lacks chromosomal relBE and rhaBAD. With this strain, we demonstrated that RelE-mediated dormancy is enhanced at high cell densities compared to that at low cell densities. The initiation of expression of the antitoxin RelB from a plasmid, pCA24N, reversed RelE-mediated dormancy in bacterial cultures. The activation of RelE increased the appearance of persister cells against β-lactams, quinolones, and aminoglycosides, and more persister cells appeared at high cell densities than at low cell densities. Further analysis indicated that amino acid starvation and an uncharacterized extracellular heat-labile substance promote RelE-mediated dormancy. This is a first report on the induction of RelE-mediated dormancy by high cell density. This work establishes a population-based dormancy mechanism to help explain E. coli survival in stressful environments.
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163
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Wei Q, Tarighi S, Dötsch A, Häussler S, Müsken M, Wright VJ, Cámara M, Williams P, Haenen S, Boerjan B, Bogaerts A, Vierstraete E, Verleyen P, Schoofs L, Willaert R, De Groote VN, Michiels J, Vercammen K, Crabbé A, Cornelis P. Phenotypic and genome-wide analysis of an antibiotic-resistant small colony variant (SCV) of Pseudomonas aeruginosa. PLoS One 2011; 6:e29276. [PMID: 22195037 PMCID: PMC3240657 DOI: 10.1371/journal.pone.0029276] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 11/23/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Small colony variants (SCVs) are slow-growing bacteria, which often show increased resistance to antibiotics and cause latent or recurrent infections. It is therefore important to understand the mechanisms at the basis of this phenotypic switch. METHODOLOGY/PRINCIPAL FINDINGS One SCV (termed PAO-SCV) was isolated, showing high resistance to gentamicin and to the cephalosporine cefotaxime. PAO-SCV was prone to reversion as evidenced by emergence of large colonies with a frequency of 10(-5) on media without antibiotics while it was stably maintained in presence of gentamicin. PAO-SCV showed a delayed growth, defective motility, and strongly reduced levels of the quorum sensing Pseudomonas quinolone signal (PQS). Whole genome expression analysis further suggested a multi-layered antibiotic resistance mechanism, including simultaneous over-expression of two drug efflux pumps (MexAB-OprM, MexXY-OprM), the LPS modification operon arnBCADTEF, and the PhoP-PhoQ two-component system. Conversely, the genes for the synthesis of PQS were strongly down-regulated in PAO-SCV. Finally, genomic analysis revealed the presence of mutations in phoP and phoQ genes as well as in the mexZ gene encoding a repressor of the mexXY and mexAB-oprM genes. Only one mutation occurred only in REV, at nucleotide 1020 of the tufA gene, a paralog of tufB, both encoding the elongation factor Tu, causing a change of the rarely used aspartic acid codon GAU to the more common GAC, possibly causing an increase of tufA mRNA translation. High expression of phoP and phoQ was confirmed for the SCV variant while the revertant showed expression levels reduced to wild-type levels. CONCLUSIONS By combining data coming from phenotypic, gene expression and proteome analysis, we could demonstrate that resistance to aminoglycosides in one SCV mutant is multifactorial including overexpression of efflux mechanisms, LPS modification and is accompanied by a drastic down-regulation of the Pseudomonas quinolone signal quorum sensing system.
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Affiliation(s)
- Qing Wei
- Research Group Microbiology, VIB Department of Structural Biology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Saeed Tarighi
- Research Group Microbiology, VIB Department of Structural Biology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Andreas Dötsch
- Chronic Pseudomonas Infections, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Susanne Häussler
- Chronic Pseudomonas Infections, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Twincore, Center for Experimental and Clinical Infection Research, Helmholtz Center for Infection Research and the Medical School Hannover, Hannover, Germany
| | - Mathias Müsken
- Chronic Pseudomonas Infections, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Twincore, Center for Experimental and Clinical Infection Research, Helmholtz Center for Infection Research and the Medical School Hannover, Hannover, Germany
| | - Victoria J. Wright
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Miguel Cámara
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Paul Williams
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Steven Haenen
- Functional Genomics and Proteomics, Faculty of Sciences, K.U. Leuven, Leuven, Belgium
| | - Bart Boerjan
- Functional Genomics and Proteomics, Faculty of Sciences, K.U. Leuven, Leuven, Belgium
| | - Annelies Bogaerts
- Functional Genomics and Proteomics, Faculty of Sciences, K.U. Leuven, Leuven, Belgium
| | - Evy Vierstraete
- Functional Genomics and Proteomics, Faculty of Sciences, K.U. Leuven, Leuven, Belgium
| | - Peter Verleyen
- Functional Genomics and Proteomics, Faculty of Sciences, K.U. Leuven, Leuven, Belgium
| | - Liliane Schoofs
- Functional Genomics and Proteomics, Faculty of Sciences, K.U. Leuven, Leuven, Belgium
| | - Ronnie Willaert
- Structural Biology Brussels, VIB Department of Structural Biology, Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Jan Michiels
- Centre of Microbial and Plant Genetics, K.U. Leuven, Heverlee, Belgium
| | - Ken Vercammen
- Research Group Microbiology, VIB Department of Structural Biology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Aurélie Crabbé
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Pierre Cornelis
- Research Group Microbiology, VIB Department of Structural Biology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- * E-mail:
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164
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Balaban NQ. Persistence: mechanisms for triggering and enhancing phenotypic variability. Curr Opin Genet Dev 2011; 21:768-75. [DOI: 10.1016/j.gde.2011.10.001] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 09/19/2011] [Accepted: 10/04/2011] [Indexed: 11/28/2022]
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165
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Antigny F, Norez C, Becq F, Vandebrouck C. CFTR and Ca Signaling in Cystic Fibrosis. Front Pharmacol 2011; 2:67. [PMID: 22046162 PMCID: PMC3200540 DOI: 10.3389/fphar.2011.00067] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 10/11/2011] [Indexed: 11/13/2022] Open
Abstract
Among the diverse physiological functions exerted by calcium signaling in living cells, its role in the regulation of protein biogenesis and trafficking remains incompletely understood. In cystic fibrosis (CF) disease the most common CF transmembrane conductance regulator (CFTR) mutation, F508del-CFTR generates a misprocessed protein that is abnormally retained in the endoplasmic reticulum (ER) compartment, rapidly degraded by the ubiquitin/proteasome pathway and hence absent at the plasma membrane of CF epithelial cells. Recent studies have demonstrated that intracellular calcium signals consequent to activation of apical G-protein-coupled receptors by different agonists are increased in CF airway epithelia. Moreover, the regulation of various intracellular calcium storage compartments, such as ER is also abnormal in CF cells. Although the molecular mechanism at the origin of this increase remains puzzling in epithelial cells, the F508del-CFTR mutation is proposed to be the onset of abnormal Ca2+ influx linking the calcium signaling to CFTR pathobiology. This article reviews the relationships between CFTR and calcium signaling in the context of the genetic disease CF.
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Affiliation(s)
- Fabrice Antigny
- Institut de Physiologie et de Biologie Cellulaires, Université de Poitiers, CNRS Poitiers, France
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166
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Fauvart M, De Groote VN, Michiels J. Role of persister cells in chronic infections: clinical relevance and perspectives on anti-persister therapies. J Med Microbiol 2011; 60:699-709. [PMID: 21459912 DOI: 10.1099/jmm.0.030932-0] [Citation(s) in RCA: 298] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Certain infectious diseases caused by pathogenic bacteria are typically chronic in nature. Potentially deadly examples include tuberculosis, caused by Mycobacterium tuberculosis, cystic fibrosis-associated lung infections, primarily caused by Pseudomonas aeruginosa, and candidiasis, caused by the fungal pathogen Candida albicans. A hallmark of this type of illness is the recalcitrance to treatment with antibiotics, even in the face of laboratory tests showing the causative agents to be sensitive to drugs. Recent studies have attributed this treatment failure to the presence of a small, transiently multidrug-tolerant subpopulation of cells, so-called persister cells. Here, we review our current understanding of the role that persisters play in the treatment and outcome of chronic infections. In a second part, we offer a perspective on the development of anti-persister therapies based on genes and mechanisms that have been implicated in persistence over the last decade.
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Affiliation(s)
- Maarten Fauvart
- Centre of Microbial and Plant Genetics, K.U.Leuven, Leuven, Belgium
| | | | - Jan Michiels
- Centre of Microbial and Plant Genetics, K.U.Leuven, Leuven, Belgium
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167
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Shapiro JA, Nguyen VL, Chamberlain NR. Evidence for persisters in Staphylococcus epidermidis RP62a planktonic cultures and biofilms. J Med Microbiol 2011; 60:950-960. [PMID: 21415203 DOI: 10.1099/jmm.0.026013-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The pathogenesis of Staphylococcus epidermidis in foreign device-related infections is attributed primarily to its ability to form biofilms on a polymer surface. One mechanism proposed for the survival of organisms in a biofilm is the presence of persister cells. Persister cells survive antibiotic treatment without acquiring heritable antibiotic resistance. This study was conducted to determine if S. epidermidis RP62a growing in planktonic cultures and biofilms could survive as persister cells following treatment with levofloxacin and vancomycin. S. epidermidis RP62a produced a small percentage of persisters (levofloxacin, 3.09×10⁻⁷%; vancomycin, 8.21×10⁻⁵ %) when grown to exponential phase, whereas biofilms contained 28 and 94 % persisters, following exposure to levofloxacin and vancomycin, respectively. The highest percentages of persisters were obtained during stationary phase in planktonic cultures and the lowest percentages of persisters were obtained during mid-exponential phase. An increase in persister number was not due to activation of quorum-sensing regulons. Confocal laser scanning microscopy images of biofilms exposed to levofloxacin demonstrated that the antibiotic was able to kill bacteria throughout the biofilm. Our results suggest that antibiotic tolerance in biofilms and in planktonic cultures of S. epidermidis RP62a is due in part to the presence of persister cells.
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Affiliation(s)
- Julie A Shapiro
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, 800 West Jefferson Street, Kirksville, MO 63501, USA
| | - Valerie L Nguyen
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, 800 West Jefferson Street, Kirksville, MO 63501, USA
| | - Neal R Chamberlain
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, 800 West Jefferson Street, Kirksville, MO 63501, USA
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168
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Mayer ML, Sheridan JA, Blohmke CJ, Turvey SE, Hancock REW. The Pseudomonas aeruginosa autoinducer 3O-C12 homoserine lactone provokes hyperinflammatory responses from cystic fibrosis airway epithelial cells. PLoS One 2011; 6:e16246. [PMID: 21305014 PMCID: PMC3031552 DOI: 10.1371/journal.pone.0016246] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 12/07/2010] [Indexed: 12/02/2022] Open
Abstract
The discovery of novel antiinflammatory targets to treat inflammation in the cystic fibrosis (CF) lung stands to benefit patient populations suffering with this disease. The Pseudomonas aeruginosa quorum sensing autoinducer N-3-oxododecanoyl homoserine lactone (3O-C12) is an important bacterial virulence factor that has been reported to induce proinflammatory cytokine production from a variety of cell types. The goal of this study was to examine the ability of 3O-C12 to induce proinflammatory cytokine production in normal and CF bronchial epithelial cells, and better understand the cellular mechanisms by which this cytokine induction occurs. 3O-C12 was found to induce higher levels of IL-6 production in the CF cell lines IB3-1 and CuFi, compared to their corresponding control cell lines C38 and NuLi. Systems biology and network analysis revealed a high predominance of over-represented innate immune pathways bridged together by calcium-dependant transcription factors governing the transcriptional responses of A549 airway cells to stimulation with 3O-C12. Using calcium-flux assays, 3O-C12 was found to induce larger and more sustained increases in intracellular calcium in IB3-1 cells compared to C38, and blocking this calcium flux with BAPTA-AM reduced the production of IL-6 by IB3-1 to the levels produced by C38. These data suggest that 3O-C12 induces proinflammatory cytokine production in airway epithelial cells in a calcium-dependent manner, and that dysregulated calcium storage or signalling in CF cells results in an increased production of proinflammatory cytokines.
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Affiliation(s)
- Matthew L. Mayer
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
| | - Jared A. Sheridan
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
| | - Christoph J. Blohmke
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- Child and Family Research Institute, BC Children's Hospital, Vancouver, Canada
| | - Stuart E. Turvey
- Department of Pediatrics, University of British Columbia, Vancouver, Canada
- Child and Family Research Institute, BC Children's Hospital, Vancouver, Canada
| | - Robert E. W. Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, Canada
- * E-mail:
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169
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De Groote VN, Fauvart M, Kint CI, Verstraeten N, Jans A, Cornelis P, Michiels J. Pseudomonas aeruginosa fosfomycin resistance mechanisms affect non-inherited fluoroquinolone tolerance. J Med Microbiol 2011; 60:329-336. [PMID: 21212150 DOI: 10.1099/jmm.0.019703-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that poses a threat in clinical settings due to its intrinsic and acquired resistance to a wide spectrum of antibiotics. Additionally, the presence of a subpopulation of cells surviving high concentrations of antibiotics, called persisters, makes it virtually impossible to eradicate a chronic infection. The mechanism underlying persistence is still unclear, partly due to the fact that it is a non-inherited phenotype. Based on our findings from a previously performed screening effort for P. aeruginosa persistence genes, we hypothesize that crosstalk can occur between two clinically relevant mechanisms: the persistence phenomenon and antibiotic resistance. This was tested by determining the persistence phenotype of P. aeruginosa strains that are resistant to the antibiotic fosfomycin due to either of two unrelated fosfomycin resistance mechanisms. Overexpression of fosA (PA1129) confers fosfomycin resistance by enzymic modification of the antibiotic, and in addition causes a decrease in the number of persister cells surviving ofloxacin treatment. Both phenotypes require the enzymic function of FosA, as mutation of the Arg119 residue abolishes fosfomycin resistance as well as low persistence. The role for fosfomycin resistance mechanisms in persistence is corroborated by demonstrating a similar phenotype in a strain with a mutation in glpT (PA5235), which encodes a glycerol-3-phosphate transporter essential for fosfomycin uptake. These results indicate that fosfomycin resistance, conferred by glpT mutation or by overexpression of fosA, results in a decrease in the number of persister cells after treatment with ofloxacin and additionally stress that further research into the interplay between fosfomycin resistance and persistence is warranted.
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Affiliation(s)
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Cyrielle I Kint
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | | | - Ann Jans
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Pierre Cornelis
- Department of Molecular and Cellular Interactions, Laboratory of Microbial Interactions, Flanders Interuniversity Institute for Biotechnology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
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170
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Bialasiewicz AA, Breidenbach KA, Klauss V, Al-Saeidi RM, Shenoy R, Bischoff G. Clinical management of infectious contact lens complications: from antibiotics to quorum-sensing inhibitors. EXPERT REVIEW OF OPHTHALMOLOGY 2010. [DOI: 10.1586/eop.10.74] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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171
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Coenye T. Social interactions in the Burkholderia cepacia complex: biofilms and quorum sensing. Future Microbiol 2010; 5:1087-99. [DOI: 10.2217/fmb.10.68] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Burkholderia cepacia complex bacteria are opportunistic pathogens that cause respiratory tract infections in susceptible patients, mainly people with cystic fibrosis. There is convincing evidence that B. cepacia complex bacteria can form biofilms, not only on abiotic surfaces (e.g., glass and plastics), but also on biotic surfaces such as epithelial cells, leading to the suggestion that biofilm formation plays a key role in persistent infection of cystic fibrosis lungs. This article presents an overview of the molecular mechanisms involved in B. cepacia complex biofilm formation, the increased resistance of sessile B. cepacia complex cells and the role of quorum sensing in B. cepacia complex biofilm formation.
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Affiliation(s)
- Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Harelbekestraat 72, B-9000 Gent, Belgium
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