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Horn J, Klepsch M, Manger M, Wolz C, Rudel T, Fraunholz M. Long Noncoding RNA SSR42 Controls Staphylococcus aureus Alpha-Toxin Transcription in Response to Environmental Stimuli. J Bacteriol 2018; 200:e00252-18. [PMID: 30150231 PMCID: PMC6199474 DOI: 10.1128/jb.00252-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 08/22/2018] [Indexed: 02/02/2023] Open
Abstract
Staphylococcus aureus is a human pathogen causing a variety of diseases by versatile expression of a large set of virulence factors that most prominently features the cytotoxic and hemolytic pore-forming alpha-toxin. Expression of alpha-toxin is regulated by an intricate network of transcription factors. These include two-component systems sensing quorum and environmental signals as well as regulators reacting to the nutritional status of the pathogen. We previously identified the repressor of surface proteins (Rsp) as a virulence regulator. Acute cytotoxicity and hemolysis are strongly decreased in rsp mutants, which are characterized by decreased transcription of toxin genes as well as loss of transcription of a 1,232-nucleotide (nt)-long noncoding RNA (ncRNA), SSR42. Here, we show that SSR42 is the effector of Rsp in transcription regulation of the alpha-toxin gene, hla SSR42 transcription is enhanced after exposure of S. aureus to subinhibitory concentrations of oxacillin which thus leads to an SSR42-dependent increase in hemolysis. Aside from Rsp, SSR42 transcription is under the control of additional global regulators, such as CodY, AgrA, CcpE, and σB, but is positioned upstream of the two-component system SaeRS in the regulatory cascade leading to alpha-toxin production. Thus, alpha-toxin expression depends on two long ncRNAs, SSR42 and RNAIII, which control production of the cytolytic toxin on the transcriptional and translational levels, respectively, with SSR42 as an important regulator of SaeRS-dependent S. aureus toxin production in response to environmental and metabolic signals.IMPORTANCEStaphylococcus aureus is a major cause of life-threatening infections. The bacterium expresses alpha-toxin, a hemolysin and cytotoxin responsible for many of the pathologies of S. aureus Alpha-toxin production is enhanced by subinhibitory concentrations of antibiotics. Here, we show that this process is dependent on the long noncoding RNA, SSR42. Further, SSR42 itself is regulated by several global regulators, thereby integrating environmental and nutritional signals that modulate hemolysis of the pathogen.
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Affiliation(s)
- Jessica Horn
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | - Maximilian Klepsch
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | - Michelle Manger
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | - Christiane Wolz
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Thomas Rudel
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
| | - Martin Fraunholz
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
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52
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Barros RPC, Cunha EVLD, Catão RMR, Scotti L, Souza MSR, Brás AAQ, Scotti MT. Virtual screening of secondary metabolites of the genus Solanum with potential antimicrobial activity. REVISTA BRASILEIRA DE FARMACOGNOSIA-BRAZILIAN JOURNAL OF PHARMACOGNOSY 2018. [DOI: 10.1016/j.bjp.2018.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Genome Plasticity of agr-Defective Staphylococcus aureus during Clinical Infection. Infect Immun 2018; 86:IAI.00331-18. [PMID: 30061376 PMCID: PMC6204747 DOI: 10.1128/iai.00331-18] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/21/2018] [Indexed: 01/05/2023] Open
Abstract
Therapy for bacteremia caused by Staphylococcus aureus is often ineffective, even when treatment conditions are optimal according to experimental protocols. Adapted subclones, such as those bearing mutations that attenuate agr-mediated virulence activation, are associated with persistent infection and patient mortality. Therapy for bacteremia caused by Staphylococcus aureus is often ineffective, even when treatment conditions are optimal according to experimental protocols. Adapted subclones, such as those bearing mutations that attenuate agr-mediated virulence activation, are associated with persistent infection and patient mortality. To identify additional alterations in agr-defective mutants, we sequenced and assembled the complete genomes of clone pairs from colonizing and infected sites of several patients in whom S. aureus demonstrated a within-host loss of agr function. We report that events associated with agr inactivation result in agr-defective blood and nares strain pairs that are enriched in mutations compared to pairs from wild-type controls. The random distribution of mutations between colonizing and infecting strains from the same patient, and between strains from different patients, suggests that much of the genetic complexity of agr-defective strains results from prolonged infection or therapy-induced stress. However, in one of the agr-defective infecting strains, multiple genetic changes resulted in increased virulence in a murine model of bloodstream infection, bypassing the mutation of agr and raising the possibility that some changes were selected. Expression profiling correlated the elevated virulence of this agr-defective mutant to restored expression of the agr-regulated ESAT6-like type VII secretion system, a known virulence factor. Thus, additional mutations outside the agr locus can contribute to diversification and adaptation during infection by S. aureus agr mutants associated with poor patient outcomes.
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54
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Krishna A, Holden MTG, Peacock SJ, Edwards AM, Wigneshweraraj S. Naturally occurring polymorphisms in the virulence regulator Rsp modulate Staphylococcus aureus survival in blood and antibiotic susceptibility. MICROBIOLOGY (READING, ENGLAND) 2018; 164:1189-1195. [PMID: 30028663 PMCID: PMC6230762 DOI: 10.1099/mic.0.000695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/03/2018] [Indexed: 01/20/2023]
Abstract
Nasal colonization by the pathogen Staphylococcus aureus is a risk factor for subsequent infection. Loss of function mutations in the gene encoding the virulence regulator Rsp are associated with the transition of S. aureus from a colonizing isolate to one that causes bacteraemia. Here, we report the identification of several novel activity-altering mutations in rsp detected in clinical isolates, including for the first time, mutations that enhance agr operon activity. We assessed how these mutations affected infection-relevant phenotypes and found loss and enhancement of function mutations to have contrasting effects on S. aureus survival in blood and antibiotic susceptibility. These findings add to the growing body of evidence that suggests S. aureus 'trades off' virulence for the acquisition of traits that benefit survival in the host, and indicates that infection severity and treatment options can be significantly affected by mutations in the virulence regulator rsp.
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Affiliation(s)
- Aishwarya Krishna
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Matthew T. G. Holden
- Wellcome Trust Sanger Institute, Hinxton, UK
- School of Medicine, University of St Andrews, St Andrews, UK
| | - Sharon J. Peacock
- Wellcome Trust Sanger Institute, Hinxton, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | - Andrew M. Edwards
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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55
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Foster TJ. Can β-Lactam Antibiotics Be Resurrected to Combat MRSA? Trends Microbiol 2018; 27:26-38. [PMID: 30031590 DOI: 10.1016/j.tim.2018.06.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/25/2018] [Accepted: 06/22/2018] [Indexed: 01/26/2023]
Abstract
The use of β-lactam antibiotics to treat infections caused by Staphylococcus aureus has been severely compromised by the acquisition by horizontal gene transfer of a gene that encodes the β-lactam-insensitive penicillin-binding protein PBP2a. This allows methicillin-resistant S. aureus (MRSA) to proliferate in the presence of β-lactam antibiotics. Paradoxically the dependence on PBP2a for the essential transpeptidase activity in cell wall peptidoglycan biosynthesis is the 'Achilles heel' of MRSA. Compounds that disrupt the divisome, wall teichoic acid, and functional membrane microdomains act synergistically with β-lactams against MRSA. These include drugs such as statins that are widely used in human medicine. The antibiotics vancomycin and daptomycin are also synergistic with β-lactams, and combinations have been employed to treat persistent MRSA infections. An additional benefit of exposing MRSA to β-lactams could be a reduction in virulence mediated by interfering with the global regulator Agr. The mechanistic basis of synergy is discussed, and the possibility that β-lactams can be resurrected to combat MRSA infections is explored.
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Affiliation(s)
- Timothy J Foster
- Microbiology Department, Trinity College Dublin, Dublin 2, Ireland.
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56
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Mannala GK, Koettnitz J, Mohamed W, Sommer U, Lips KS, Spröer C, Bunk B, Overmann J, Hain T, Heiss C, Domann E, Alt V. Whole-genome comparison of high and low virulent Staphylococcus aureus isolates inducing implant-associated bone infections. Int J Med Microbiol 2018; 308:505-513. [DOI: 10.1016/j.ijmm.2018.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/08/2018] [Accepted: 04/22/2018] [Indexed: 11/16/2022] Open
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Benoit JB, Frank DN, Bessesen MT. Genomic evolution of Staphylococcus aureus isolates colonizing the nares and progressing to bacteremia. PLoS One 2018; 13:e0195860. [PMID: 29723202 PMCID: PMC5933776 DOI: 10.1371/journal.pone.0195860] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/31/2018] [Indexed: 12/21/2022] Open
Abstract
Background Nasal colonization by Staphylococcus aureus is a key risk factor for bacteremia. The objective of this study is to identify genomic modifications occurring in nasal carriage strains of S. aureus as they progress to bacteremia in a cohort of hospitalized patients. Methods Eight patients with S. aureus bacteremia were identified. Genomic sequences of the bloodstream isolates were compared with 57 nasal isolates collected longitudinally prior to the occurrence of bacteremia, which covered a timespan of up to 326 days before bacteremia. Results Within each subject, nasal colonizing strains were closely related to bacteremia strains. Within a subject, the number of single nucleotide polymorphisms (SNPs) observed between time points was greater than within a single time point. Co-colonization and strain replacement were observed in one case. In all cases colonization progressed to bacteremia without addition of new virulence genes. In one case, a mutation in the accessory gene regulator gene caused abrogation of agr function. Conclusion S. aureus evolves in the human nares at a variable rate. Progression of S. aureus nasal colonization to nosocomial infection is seldom associated with acquisition of new virulence determinants. Mutation in the agr gene with abrogation of function was associated with progression to bacteremia in one case.
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Affiliation(s)
- Jeanne B. Benoit
- Division of Infectious Diseases, Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Veterans Affairs Eastern Colorado Healthcare System, Denver, Colorado, United States of America
| | - Daniel N. Frank
- Division of Infectious Diseases, Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Veterans Affairs Eastern Colorado Healthcare System, Denver, Colorado, United States of America
| | - Mary T. Bessesen
- Division of Infectious Diseases, Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Veterans Affairs Eastern Colorado Healthcare System, Denver, Colorado, United States of America
- * E-mail:
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58
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Suligoy CM, Lattar SM, Noto Llana M, González CD, Alvarez LP, Robinson DA, Gómez MI, Buzzola FR, Sordelli DO. Mutation of Agr Is Associated with the Adaptation of Staphylococcus aureus to the Host during Chronic Osteomyelitis. Front Cell Infect Microbiol 2018; 8:18. [PMID: 29456969 PMCID: PMC5801681 DOI: 10.3389/fcimb.2018.00018] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 01/12/2018] [Indexed: 11/13/2022] Open
Abstract
Selection pressures exerted on Staphylococcus aureus by host factors may lead to the emergence of mutants better adapted to the evolving conditions at the infection site. This study was aimed at identifying the changes that occur in S. aureus exposed to the host defense mechanisms during chronic osteomyelitis and evaluating whether these changes affect the virulence of the organism. Genome assessment of two S. aureus isolates collected 13 months apart (HU-85a and HU-85c) from a host with chronic osteomyelitis was made by whole genome sequencing. Agr functionality was assessed by qRT-PCR. Isolates were tested in a rat model of osteomyelitis and the bacterial load (CFU/tibia) and the morphometric osteomyelitic index (OI) were determined. The ability of the isolates to trigger the release of proinflammatory cytokines was determined on macrophages in culture. Persistence of S. aureus within the host resulted in an agrC frameshift mutation that likely led to the observed phenotype. The capacity to cause bone tissue damage and trigger proinflammatory cytokines by macrophages of the agr-deficient, unencapsulated derivative (HU-85c) was decreased when compared with those of the isogenic CP8-capsulated parental strain (HU-85a). By comparison, no significant differences were found in the bacterial load or the OI from rats challenged with isogenic Reynolds strains [CP5, CP8, and non-typeable (NT)], indicating that lack of CP expression alone was not likely responsible for the reduced capacity to cause tissue damage in HU-85c compared with HU-85a. The production of biofilm was significantly increased in the isogenic derivative HU-85c. Lack of agr-dependent factors makes S. aureus less virulent during chronic osteomyelitis and alteration of the agr functionality seems to permit better adaptation of S. aureus to the chronically infected host.
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Affiliation(s)
- Carlos M Suligoy
- Instituto de Investigaciones en Microbiología y Parasitología Médica, University of Buenos Aires - CONICET, Buenos Aires, Argentina
| | - Santiago M Lattar
- Instituto de Investigaciones en Microbiología y Parasitología Médica, University of Buenos Aires - CONICET, Buenos Aires, Argentina
| | - Mariángeles Noto Llana
- Instituto de Investigaciones en Microbiología y Parasitología Médica, University of Buenos Aires - CONICET, Buenos Aires, Argentina
| | - Cintia D González
- Instituto de Investigaciones en Microbiología y Parasitología Médica, University of Buenos Aires - CONICET, Buenos Aires, Argentina
| | - Lucía P Alvarez
- Instituto de Investigaciones en Microbiología y Parasitología Médica, University of Buenos Aires - CONICET, Buenos Aires, Argentina
| | - D Ashley Robinson
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Marisa I Gómez
- Instituto de Investigaciones en Microbiología y Parasitología Médica, University of Buenos Aires - CONICET, Buenos Aires, Argentina
| | - Fernanda R Buzzola
- Instituto de Investigaciones en Microbiología y Parasitología Médica, University of Buenos Aires - CONICET, Buenos Aires, Argentina
| | - Daniel O Sordelli
- Instituto de Investigaciones en Microbiología y Parasitología Médica, University of Buenos Aires - CONICET, Buenos Aires, Argentina
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59
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Young BC, Wu CH, Gordon NC, Cole K, Price JR, Liu E, Sheppard AE, Perera S, Charlesworth J, Golubchik T, Iqbal Z, Bowden R, Massey RC, Paul J, Crook DW, Peto TE, Walker AS, Llewelyn MJ, Wyllie DH, Wilson DJ. Severe infections emerge from commensal bacteria by adaptive evolution. eLife 2017; 6. [PMID: 29256859 PMCID: PMC5736351 DOI: 10.7554/elife.30637] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 12/02/2017] [Indexed: 12/23/2022] Open
Abstract
Bacteria responsible for the greatest global mortality colonize the human microbiota far more frequently than they cause severe infections. Whether mutation and selection among commensal bacteria are associated with infection is unknown. We investigated de novo mutation in 1163 Staphylococcus aureus genomes from 105 infected patients with nose colonization. We report that 72% of infections emerged from the nose, with infecting and nose-colonizing bacteria showing parallel adaptive differences. We found 2.8-to-3.6-fold adaptive enrichments of protein-altering variants in genes responding to rsp, which regulates surface antigens and toxin production; agr, which regulates quorum-sensing, toxin production and abscess formation; and host-derived antimicrobial peptides. Adaptive mutations in pathogenesis-associated genes were 3.1-fold enriched in infecting but not nose-colonizing bacteria. None of these signatures were observed in healthy carriers nor at the species-level, suggesting infection-associated, short-term, within-host selection pressures. Our results show that signatures of spontaneous adaptive evolution are specifically associated with infection, raising new possibilities for diagnosis and treatment.
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Affiliation(s)
- Bernadette C Young
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,Microbiology and Infectious Diseases Department, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Chieh-Hsi Wu
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom
| | - N Claire Gordon
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom
| | - Kevin Cole
- Department of Infectious Diseases and Microbiology, Royal Sussex County Hospital, Brighton, United Kingdom
| | - James R Price
- Department of Infectious Diseases and Microbiology, Royal Sussex County Hospital, Brighton, United Kingdom.,Department of Global Health and Infection, Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - Elian Liu
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,Microbiology and Infectious Diseases Department, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Anna E Sheppard
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,NIHR Health Protection Unit in Healthcare Associated Infections and Antimicrobial Resistance at University of Oxford in partnership with Public Health England, Oxford, United Kingdom
| | - Sanuki Perera
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,Microbiology and Infectious Diseases Department, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Jane Charlesworth
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom
| | - Tanya Golubchik
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom
| | - Zamin Iqbal
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Rory Bowden
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Ruth C Massey
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - John Paul
- National Infection Service, Public Health England, London, United Kingdom.,National Institute for Health Research, Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Derrick W Crook
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,National Infection Service, Public Health England, London, United Kingdom.,National Institute for Health Research, Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Timothy E Peto
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,National Institute for Health Research, Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - A Sarah Walker
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,National Institute for Health Research, Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Martin J Llewelyn
- Department of Infectious Diseases and Microbiology, Royal Sussex County Hospital, Brighton, United Kingdom.,Department of Global Health and Infection, Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - David H Wyllie
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,Centre for Molecular and Cellular Physiology, Jenner Institute, Oxford, United Kingdom
| | - Daniel J Wilson
- Nuffield Department of Medicine, Experimental Medicine Division, University of Oxford, Oxford, United Kingdom.,Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.,Institute for Emerging Infections, Oxford Martin School, University of Oxford, Oxford, United Kingdom
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60
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Horn J, Stelzner K, Rudel T, Fraunholz M. Inside job: Staphylococcus aureus host-pathogen interactions. Int J Med Microbiol 2017; 308:607-624. [PMID: 29217333 DOI: 10.1016/j.ijmm.2017.11.009] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/17/2017] [Accepted: 11/21/2017] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus is a notorious opportunistic pathogen causing a plethora of diseases. Recent research established that once phagocytosed by neutrophils and macrophages, a certain percentage of S. aureus is able to survive within these phagocytes which thereby even may contribute to dissemination of the pathogen. S. aureus further induces its uptake by otherwise non-phagocytic cells and the ensuing intracellular cytotoxicity is suggested to lead to tissue destruction, whereas bacterial persistence within cells is thought to lead to immune evasion and chronicity of infections. We here review recent work on the S. aureus host pathogen interactions with a focus on the intracellular survival of the pathogen.
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Affiliation(s)
- Jessica Horn
- Chair of Microbiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Kathrin Stelzner
- Chair of Microbiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Thomas Rudel
- Chair of Microbiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Martin Fraunholz
- Chair of Microbiology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
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61
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Xu T, Wang XY, Cui P, Zhang YM, Zhang WH, Zhang Y. The Agr Quorum Sensing System Represses Persister Formation through Regulation of Phenol Soluble Modulins in Staphylococcus aureus. Front Microbiol 2017; 8:2189. [PMID: 29163457 PMCID: PMC5681930 DOI: 10.3389/fmicb.2017.02189] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/25/2017] [Indexed: 12/30/2022] Open
Abstract
The opportunistic pathogen Staphylococcus aureus has become an increasing threat to public health. While the Agr quorum sensing (QS) system is a master regulator of S. aureus virulence, its dysfunction has been frequently reported to promote bacteremia and mortality in clinical infections. Here we show that the Agr system is involved in persister formation in S. aureus. Mutation of either agrCA or agrD but not RNAIII resulted in increased persister formation of stationary phase cultures. RNA-seq analysis showed that in stationary phase AgrCA/AgrD and RNAIII mutants showed consistent up-regulation of virulence associated genes (lip and splE, etc.) and down-regulation of metabolism genes (bioA and nanK, etc.). Meanwhile, though knockout of agrCA or agrD strongly repressed expression of phenol soluble modulin encoding genes psmα1-4, psmβ1-2 and phenol soluble modulins (PSM) transporter encoding genes in the pmt operon, mutation of RNAIII enhanced expression of the genes. We further found that knockout of psmα1-4 or psmβ1-2 augmented persister formation and that co-overexpression of PSMαs and PSMβs reversed the effects of AgrCA mutation on persister formation. We also detected the effects on persister formation by mutations of metabolism genes (arcA, hutU, narG, nanK, etc.) that are potentially regulated by Agr system. It was found that deletion of the ManNAc kinase encoding gene nanK decreased persister formation. Taken together, these results shed new light on the PSM dependent regulatory role of Agr system in persister formation and may have implications for clinical treatment of MRSA persistent infections.
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Affiliation(s)
- Tao Xu
- Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xu-Yang Wang
- Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Peng Cui
- Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Yu-Meng Zhang
- Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Wen-Hong Zhang
- Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Ying Zhang
- Key Laboratory of Medical Molecular Virology, Huashan Hospital, Shanghai Medical College of Fudan University, Shanghai, China
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States
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62
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Tuning of the Lethal Response to Multiple Stressors with a Single-Site Mutation during Clinical Infection by Staphylococcus aureus. mBio 2017; 8:mBio.01476-17. [PMID: 29066545 PMCID: PMC5654930 DOI: 10.1128/mbio.01476-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The agr system of Staphylococcus aureus promotes invasion of host tissues, and as expected, agents that block agr quorum sensing have anti-infective properties. Paradoxically, agr-defective mutants are frequently recovered from patients, especially those persistently infected with S. aureus We found that an agr deficiency increased survival of cultured bacteria during severe stress, such as treatment with gentamicin, ciprofloxacin, heat, or low pH. With daptomycin, deletion of agr decreased survival. Therefore, agr activity can be either detrimental or protective, depending on the type of lethal stress. Deletion of agr had no effect on the ability of the antimicrobials to block bacterial growth, indicating that agr effects are limited to lethal action. Thus, the effect of an agr deletion is on bacterial tolerance, not resistance. For gentamicin and daptomycin, activity can be altered by agr-regulated secreted factors. For ciprofloxacin, a detrimental function was downregulation of glutathione peroxidase (bsaA), an enzyme responsible for defense against oxidative stress. Deficiencies in agr and bsaA were epistatic for survival, consistent with agr having a destructive role mediated by reactive oxygen species. Enhanced susceptibility to lethal stress by wild-type agr, particularly antimicrobial stress, helps explain why inactivating mutations in S. aureus agr commonly occur in hospitalized patients during infection. Moreover, the agr quorum-sensing system of S. aureus provides a clinically relevant example in which a single-step change in the response to severe stress alters the evolutionary path of a pathogen during infection.IMPORTANCE When phenotypes produced in response to an environmental stress are inadequate to buffer against that stress, changes that do buffer may become genetically encoded by natural selection. A clinically relevant example is seen with S. aureus mutants that are deficient in the key virulence regulator agr Paradoxically, defects in agr are selected during serious hospital infection and have been associated with worse outcome. The current work helps resolve this paradox: agr mutants are often less readily killed by lethal stressors without affecting MIC, a phenomenon known as tolerance. Our results indicate that tolerance, which would not be detected as resistance, can be selected in clinical settings. The data also support the ideas that (i) S. aureus broadly hedges against environmental change and stress through genome plasticity, (ii) reactive oxygen can be involved in the self-destructive response in bacteria, and (iii) therapeutic targeting of agr and virulence can be counterproductive.
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63
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Weinert LA, Welch JJ. Why Might Bacterial Pathogens Have Small Genomes? Trends Ecol Evol 2017; 32:936-947. [PMID: 29054300 DOI: 10.1016/j.tree.2017.09.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 12/31/2022]
Abstract
Bacteria that cause serious disease often have smaller genomes, and fewer genes, than their nonpathogenic, or less pathogenic relatives. Here, we review evidence for the generality of this association, and summarise the various reasons why the association might hold. We focus on the population genetic processes that might lead to reductive genome evolution, and show how several of these could be connected to pathogenicity. We find some evidence for most of the processes having acted in bacterial pathogens, including several different modes of genome reduction acting in the same lineage. We argue that predictable processes of genome evolution might not reflect any common underlying process.
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Affiliation(s)
- Lucy A Weinert
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK.
| | - John J Welch
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
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64
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Abstract
The secretion of proteins that damage host tissue is well established as integral to the infectious processes of many bacterial pathogens. However, recent advances in our understanding of the activity of toxins suggest that the attributes we have assigned to them from early in vitro experimentation have misled us into thinking of them as merely destructive tools. Here, we will discuss the multifarious ways in which toxins contribute to the lifestyle of bacteria and, by considering their activity from an evolutionary perspective, demonstrate how this extends far beyond their ability to destroy host tissue.
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65
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Recker M, Laabei M, Toleman MS, Reuter S, Saunderson RB, Blane B, Török ME, Ouadi K, Stevens E, Yokoyama M, Steventon J, Thompson L, Milne G, Bayliss S, Bacon L, Peacock SJ, Massey RC. Clonal differences in Staphylococcus aureus bacteraemia-associated mortality. Nat Microbiol 2017; 2:1381-1388. [PMID: 28785103 DOI: 10.1038/s41564-017-0001-x] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 06/22/2017] [Indexed: 11/09/2022]
Abstract
The bacterium Staphylococcus aureus is a major human pathogen for which the emergence of antibiotic resistance is a global public health concern. Infection severity, and in particular bacteraemia-associated mortality, has been attributed to several host-related factors, such as age and the presence of comorbidities. The role of the bacterium in infection severity is less well understood, as it is complicated by the multifaceted nature of bacterial virulence, which has so far prevented a robust mapping between genotype, phenotype and infection outcome. To investigate the role of bacterial factors in contributing to bacteraemia-associated mortality, we phenotyped a collection of sequenced clinical S. aureus isolates from patients with bloodstream infections, representing two globally important clonal types, CC22 and CC30. By adopting a genome-wide association study approach we identified and functionally verified several genetic loci that affect the expression of cytolytic toxicity and biofilm formation. By analysing the pooled data comprising bacterial genotype and phenotype together with clinical metadata within a machine-learning framework, we found significant clonal differences in the determinants most predictive of poor infection outcome. Whereas elevated cytolytic toxicity in combination with low levels of biofilm formation was predictive of an increased risk of mortality in infections by strains of a CC22 background, these virulence-specific factors had little influence on mortality rates associated with CC30 infections. Our results therefore suggest that different clones may have adopted different strategies to overcome host responses and cause severe pathology. Our study further demonstrates the use of a combined genomics and data analytic approach to enhance our understanding of bacterial pathogenesis at the individual level, which will be an important step towards personalized medicine and infectious disease management.
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Affiliation(s)
- Mario Recker
- Centre for Mathematics & the Environment, University of Exeter, Penryn, TR10 9EZ, UK
| | - Maisem Laabei
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | | | - Sandra Reuter
- Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ, UK
| | | | - Beth Blane
- Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - M Estee Török
- Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Khadija Ouadi
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | - Emily Stevens
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | - Maho Yokoyama
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | - Joseph Steventon
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | - Luke Thompson
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | - Gregory Milne
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | - Sion Bayliss
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | - Leann Bacon
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK
| | - Sharon J Peacock
- Department of Medicine, University of Cambridge, Cambridge, CB2 0QQ, UK.,London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Ruth C Massey
- Department of Biology and Biochemistry and the Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK. .,School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, UK.
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66
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Inactivation of Transcriptional Regulators during Within-Household Evolution of Escherichia coli. J Bacteriol 2017; 199:JB.00036-17. [PMID: 28439032 DOI: 10.1128/jb.00036-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/13/2017] [Indexed: 01/24/2023] Open
Abstract
We analyzed the within-household evolution of two household-associated Escherichia coli strains from pandemic clonal group ST131-H30, using isolates recovered from five individuals within two families, each of which had a distinct strain. Family 1's strain was represented by a urine isolate from the index patient (older sister) with recurrent cystitis and a blood isolate from her younger sister with fatal urosepsis. Family 2's strain was represented by a urine isolate from the index patient (father) with pyelonephritis and renal abscesses, blood and kidney drainage isolates from the daughter with emphysematous pyelonephritis, and urine and fecal isolates from the mother with cystitis. Collectively, the several variants of each family's strain had accumulated a total of 8 (family 1) and 39 (family 2) point mutations; no two isolates were identical. Of the 47 total mutations, 36 resulted in amino acid changes or truncation of coded proteins. Fourteen such mutations (39%) targeted genes encoding transcriptional regulators, and 9 (25%) involved DNA-binding transcription factors (TFs), which significantly exceeded the relative contribution of TF genes to the isolates' genomes (∼6%). At least one-half of the transcriptional regulator mutations were inactivating, based on phenotypic and/or transcriptional analysis. In particular, inactivating mutations in the global regulator LrhA (repressor of type 1 fimbriae and flagella) occurred in the blood isolates from both households and increased the virulence of E. coli strains in a murine sepsis model. The results indicate that E. coli undergoes adaptive evolution between and/or within hosts, generating subpopulations with distinctive phenotypes and virulence potential.IMPORTANCE The clonal evolution of bacterial strains associated with interhost transmission is poorly understood. We characterized the genome sequences of clonal descendants of two Escherichia coli strains, recovered at different time points from multiple individuals within two households who had different types of urinary tract infection. We found evidence that the E. coli strains underwent extensive mutational diversification between and within these individuals, driven disproportionately by inactivation of transcriptional regulators. In urosepsis isolates, the mutations observed in the global regulator LrhA increased bacterial virulence in a murine sepsis model. Our findings help in understanding the adaptive dynamics and strategies of E. coli during short-term natural evolution.
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67
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Wilkening RV, Federle MJ. Evolutionary Constraints Shaping Streptococcus pyogenes-Host Interactions. Trends Microbiol 2017; 25:562-572. [PMID: 28216292 DOI: 10.1016/j.tim.2017.01.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/15/2016] [Accepted: 01/23/2017] [Indexed: 02/07/2023]
Abstract
Research on the Gram-positive human-restricted pathogen Streptococcus pyogenes (Group A Streptococcus, GAS) has long focused on invasive illness, the most severe manifestations of GAS infection. Recent advances in descriptions of molecular mechanisms of GAS virulence, coupled with massive sequencing efforts to isolate genomes, have allowed the field to better understand the molecular and evolutionary changes leading to pandemic strains. These findings suggest that it is necessary to rethink the dogma involving GAS pathogenesis, and that the most productive avenues for research going forward may be investigations into GAS in its 'normal' habitat, the nasopharynx, and its ability to either live with its host in an asymptomatic lifestyle or as an agent of superficial infections. This review will consider these advances, focusing on the natural history of GAS, the evolution of pandemic strains, and novel roles for several key virulence factors that may allow the field to better understand their physiological role.
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Affiliation(s)
- Reid V Wilkening
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL 60607, USA; Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Michael J Federle
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, IL 60607, USA; Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
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68
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Lees JA, Kremer PHC, Manso AS, Croucher NJ, Ferwerda B, Serón MV, Oggioni MR, Parkhill J, Brouwer MC, van der Ende A, van de Beek D, Bentley SD. Large scale genomic analysis shows no evidence for pathogen adaptation between the blood and cerebrospinal fluid niches during bacterial meningitis. Microb Genom 2017; 3:e000103. [PMID: 28348877 PMCID: PMC5361624 DOI: 10.1099/mgen.0.000103] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 12/18/2016] [Indexed: 12/26/2022] Open
Abstract
Recent studies have provided evidence for rapid pathogen genome diversification, some of which could potentially affect the course of disease. We have previously described such variation seen between isolates infecting the blood and cerebrospinal fluid (CSF) of a single patient during a case of bacterial meningitis. Here, we performed whole-genome sequencing of paired isolates from the blood and CSF of 869 meningitis patients to determine whether such variation frequently occurs between these two niches in cases of bacterial meningitis. Using a combination of reference-free variant calling approaches, we show that no genetic adaptation occurs in either invaded niche during bacterial meningitis for two major pathogen species, Streptococcus pneumoniae and Neisseria meningitidis. This study therefore shows that the bacteria capable of causing meningitis are already able to do this upon entering the blood, and no further sequence change is necessary to cross the blood–brain barrier. Our findings place the focus back on bacterial evolution between nasopharyngeal carriage and invasion, or diversity of the host, as likely mechanisms for determining invasiveness.
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Affiliation(s)
- John A Lees
- 1Pathogen Genomics, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Philip H C Kremer
- 2Department of Neurology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, The Netherlands
| | - Ana S Manso
- 3Department of Genetics, University of Leicester, Leicester, UK
| | - Nicholas J Croucher
- 4Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Bart Ferwerda
- 2Department of Neurology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, The Netherlands
| | - Mercedes Valls Serón
- 2Department of Neurology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, The Netherlands
| | - Marco R Oggioni
- 3Department of Genetics, University of Leicester, Leicester, UK
| | - Julian Parkhill
- 1Pathogen Genomics, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Matthijs C Brouwer
- 2Department of Neurology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, The Netherlands
| | - Arie van der Ende
- 5Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, The Netherlands.,6Netherlands Reference Laboratory for Bacterial Meningitis, Academic Medical Center, Amsterdam, The Netherlands
| | - Diederik van de Beek
- 2Department of Neurology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, The Netherlands
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69
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Roetzer A, Jilma B, Eibl MM. Vaccine against toxic shock syndrome in a first-in-man clinical trial. Expert Rev Vaccines 2016; 16:81-83. [PMID: 27918218 DOI: 10.1080/14760584.2017.1268921] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
| | - Bernd Jilma
- b Department of Clinical Pharmacology , Medical University of Vienna , Vienna , Austria
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70
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Genomic Landscape of Intrahost Variation in Group A Streptococcus: Repeated and Abundant Mutational Inactivation of the fabT Gene Encoding a Regulator of Fatty Acid Synthesis. Infect Immun 2016; 84:3268-3281. [PMID: 27600505 DOI: 10.1128/iai.00608-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/08/2016] [Indexed: 01/03/2023] Open
Abstract
To obtain new information about Streptococcus pyogenes intrahost genetic variation during invasive infection, we sequenced the genomes of 2,954 serotype M1 strains recovered from a nonhuman primate experimental model of necrotizing fasciitis. A total of 644 strains (21.8%) acquired polymorphisms relative to the input parental strain. The fabT gene, encoding a transcriptional regulator of fatty acid biosynthesis genes, contained 54.5% of these changes. The great majority of polymorphisms were predicted to deleteriously alter FabT function. Transcriptome-sequencing (RNA-seq) analysis of a wild-type strain and an isogenic fabT deletion mutant strain found that between 3.7 and 28.5% of the S. pyogenes transcripts were differentially expressed, depending on the growth temperature (35°C or 40°C) and growth phase (mid-exponential or stationary phase). Genes implicated in fatty acid synthesis and lipid metabolism were significantly upregulated in the fabT deletion mutant strain. FabT also directly or indirectly regulated central carbon metabolism genes, including pyruvate hub enzymes and fermentation pathways and virulence genes. Deletion of fabT decreased virulence in a nonhuman primate model of necrotizing fasciitis. In addition, the fabT deletion strain had significantly decreased survival in human whole blood and during phagocytic interaction with polymorphonuclear leukocytes ex vivo We conclude that FabT mutant progeny arise during infection, constitute a metabolically distinct subpopulation, and are less virulent in the experimental models used here.
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71
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Blättner S, Das S, Paprotka K, Eilers U, Krischke M, Kretschmer D, Remmele CW, Dittrich M, Müller T, Schuelein-Voelk C, Hertlein T, Mueller MJ, Huettel B, Reinhardt R, Ohlsen K, Rudel T, Fraunholz MJ. Staphylococcus aureus Exploits a Non-ribosomal Cyclic Dipeptide to Modulate Survival within Epithelial Cells and Phagocytes. PLoS Pathog 2016; 12:e1005857. [PMID: 27632173 PMCID: PMC5025175 DOI: 10.1371/journal.ppat.1005857] [Citation(s) in RCA: 44] [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: 04/19/2016] [Accepted: 08/10/2016] [Indexed: 12/21/2022] Open
Abstract
Community-acquired (CA) Staphylococcus aureus cause various diseases even in healthy individuals. Enhanced virulence of CA-strains is partly attributed to increased production of toxins such as phenol-soluble modulins (PSM). The pathogen is internalized efficiently by mammalian host cells and intracellular S. aureus has recently been shown to contribute to disease. Upon internalization, cytotoxic S. aureus strains can disrupt phagosomal membranes and kill host cells in a PSM-dependent manner. However, PSM are not sufficient for these processes. Here we screened for factors required for intracellular S. aureus virulence. We infected escape reporter host cells with strains from an established transposon mutant library and detected phagosomal escape rates using automated microscopy. We thereby, among other factors, identified a non-ribosomal peptide synthetase (NRPS) to be required for efficient phagosomal escape and intracellular survival of S. aureus as well as induction of host cell death. By genetic complementation as well as supplementation with the synthetic NRPS product, the cyclic dipeptide phevalin, wild-type phenotypes were restored. We further demonstrate that the NRPS is contributing to virulence in a mouse pneumonia model. Together, our data illustrate a hitherto unrecognized function of the S. aureus NRPS and its dipeptide product during S. aureus infection.
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Affiliation(s)
- Sebastian Blättner
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | - Sudip Das
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | - Kerstin Paprotka
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
| | - Ursula Eilers
- Core Unit Functional Genomics, University of Würzburg, Würzburg, Germany
| | - Markus Krischke
- Biocenter, Chair of Pharmaceutical Biology, University of Würzburg, Würzburg, Germany
| | - Dorothee Kretschmer
- Department of Infection Biology, Interfaculty Institute for Microbiology and Infection Medicine Tübingen (IMIT), University Tübingen, Tübingen, Germany
| | | | - Marcus Dittrich
- Biocenter, Chair of Bioinformatics, University of Würzburg, Würzburg, Germany
- Institute of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Tobias Müller
- Biocenter, Chair of Bioinformatics, University of Würzburg, Würzburg, Germany
| | | | - Tobias Hertlein
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Martin J. Mueller
- Biocenter, Chair of Pharmaceutical Biology, University of Würzburg, Würzburg, Germany
| | | | | | - Knut Ohlsen
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Thomas Rudel
- Biocenter, Chair of Microbiology, University of Würzburg, Würzburg, Germany
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72
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Smeltzer MS. Staphylococcus aureus Pathogenesis: The Importance of Reduced Cytotoxicity. Trends Microbiol 2016; 24:681-682. [PMID: 27450110 DOI: 10.1016/j.tim.2016.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 07/11/2016] [Indexed: 10/21/2022]
Abstract
Toxin production clearly contributes to the pathogenesis of Staphylococcus aureus, but that does not mean it is always in the best interest of the pathogen. Indeed, the ability to limit toxin production may provide an important mechanism for persistence, dissemination, and development of invasive disease within an individual human host.
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Affiliation(s)
- Mark S Smeltzer
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, 4301W. Markham, Little Rock, AR 72205, USA.
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