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Hallenbeck M, Chua M, Collins J. The role of the universal sugar transport system components PtsI (EI) and PtsH (HPr) in Enterococcus faecium. FEMS MICROBES 2024; 5:xtae018. [PMID: 38988831 PMCID: PMC11234649 DOI: 10.1093/femsmc/xtae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/08/2024] [Accepted: 05/31/2024] [Indexed: 07/12/2024] Open
Abstract
Vancomycin-resistant enterococci (VRE) pose a serious threat to public health because of their limited treatment options. Therefore, there is an increasing need to identify novel targets to develop new drugs. Here, we examined the roles of the universal PTS components, PtsI and PtsH, in Enterococcus faecium to determine their roles in carbon metabolism, biofilm formation, stress response, and the ability to compete in the gastrointestinal tract. Clean deletion of ptsHI resulted in a significant reduction in the ability to import and metabolize simple sugars, attenuated growth rate, reduced biofilm formation, and decreased competitive fitness both in vitro and in vivo. However, no significant difference in stress survival was observed when compared with the wild type. These results suggest that targeting universal or specific PTS may provide a novel treatment strategy by reducing the fitness of E. faecium.
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Affiliation(s)
- Michelle Hallenbeck
- Department of Microbiology & Immunology, University of Louisville, Louisville, KY 40202, United States
- Center for Predictive Medicine, University of Louisville, Louisville, KY 40202, United States
| | - Michelle Chua
- Department of Microbiology & Immunology, University of Louisville, Louisville, KY 40202, United States
- Center for Predictive Medicine, University of Louisville, Louisville, KY 40202, United States
| | - James Collins
- Department of Microbiology & Immunology, University of Louisville, Louisville, KY 40202, United States
- Center for Predictive Medicine, University of Louisville, Louisville, KY 40202, United States
- Center for Microbiomics, Inflammation and Pathogenicity, University of Louisville, Louisville, KY 40202, United States
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Singh KV, Galloway-Peña J, Montealegre MC, Dong X, Murray BE. Genomic context as well as sequence of both psr and penicillin-binding protein 5 contributes to β-lactam resistance in Enterococcus faecium. mBio 2024; 15:e0017024. [PMID: 38564699 PMCID: PMC11077988 DOI: 10.1128/mbio.00170-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 03/04/2024] [Indexed: 04/04/2024] Open
Abstract
Penicillin-binding protein 5 (PBP5) of Enterococcus faecium (Efm) is vital for ampicillin resistance (AMP-R). We previously designated three forms of PBP5, namely, PBP5-S in Efm clade B strains [ampicillin susceptible (AMP-S)], PBP5-S/R (AMP-S or R), and PBP5-R (AMP-R) in clade A strains. Here, pbp5 deletion resulted in a marked reduction in AMP minimum inhibitory concentrations (MICs) to 0.01-0.09 µg/mL for clade B and 0.12-0.19 µg/mL for clade A strains; in situ complementation restored parental AMP MICs. Using D344SRF (lacking ftsW/psr/pbp5), constructs with ftsWA/psrA (from a clade A1 strain) cloned upstream of pbp5-S and pbp5-S/R alleles resulted in modest increases in MICs to 3-8 µg/mL, while high MICs (>64 µg/mL) were seen using pbp5 from A1 strains. Next, using ftsW ± psr from clade B and clade A/B and B/A hybrid constructs, the presence of psrB, even alone or in trans, resulted in much lower AMP MICs (3-8 µg/mL) than when psrA was present (MICs >64 µg/mL). qRT PCR showed relatively greater pbp5 expression (P = 0.007) with pbp5 cloned downstream of clade A1 ftsW/psr (MIC >128 µg/mL) vs when cloned downstream of clade B ftsW/psr (MIC 4-16 µg/mL), consistent with results in western blots. In conclusion, we report the effect of clade A vs B psr on AMP MICs as well as the impact of pbp5 alleles from different clades. While previously, Psr was not thought to contribute to AMP MICs in Efm, our results showed that the presence of psrB resulted in a major decrease in Efm AMP MICs. IMPORTANCE The findings of this study shed light on ampicillin resistance in Enterococcus faecium clade A strains. They underscore the significance of alterations in the amino acid sequence of penicillin-binding protein 5 (PBP5) and the pivotal role of the psr region in PBP5 expression and ampicillin resistance. Notably, the presence of a full-length psrB leads to reduced PBP5 expression and lower minimum inhibitory concentrations (MICs) of ampicillin compared to the presence of a shorter psrA, regardless of the pbp5 allele involved. Additionally, clade B E. faecium strains exhibit lower AMP MICs when both psr alleles from clades A and B are present, although it is important to consider other distinctions between clade A and B strains that may contribute to this effect. It is intriguing to note that the divergence between clade A and clade B E. faecium and the subsequent evolution of heightened AMP MICs in hospital-associated strains appear to coincide with changes in Pbp5 and psr. These changes in psr may have resulted in an inactive Psr, facilitating increased PBP5 expression and greater ampicillin resistance. These results raise the possibility that a mimicker of PsrB, if one could be designed, might be able to lower MICs of ampicillin-resistant E. faecium, thus potentially resorting ampicillin to our therapeutic armamentarium for this species.
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Affiliation(s)
- Kavindra V. Singh
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA
| | - Jessica Galloway-Peña
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA
| | - Maria Camila Montealegre
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA
- Department of Microbiology and Infectious Diseases, University of Texas Health Science Center, Houston, Texas, USA
| | - Xingxing Dong
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA
| | - Barbara E. Murray
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA
- Department of Microbiology and Infectious Diseases, University of Texas Health Science Center, Houston, Texas, USA
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Roer L, Kaya H, Tedim AP, Novais C, Coque TM, Aarestrup FM, Peixe L, Hasman H, Hammerum AM, Freitas AR. VirulenceFinder for Enterococcus faecium and Enterococcus lactis: an enhanced database for detection of putative virulence markers by using whole-genome sequencing data. Microbiol Spectr 2024; 12:e0372423. [PMID: 38329344 PMCID: PMC10913372 DOI: 10.1128/spectrum.03724-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/20/2024] [Indexed: 02/09/2024] Open
Abstract
Enterococcus faecium (Efm) is a leading cause of hospital-associated (HA) infections, often enriched in putative virulence markers (PVMs). Recently, the Efm clade B was assigned as Enterococcus lactis (Elts), which usually lack HA-Efm infection markers. Available databases for extracting PVM are incomplete and/or present an intermix of genes from Efm and Enterococcus faecalis, with distinct virulence profiles. In this study, we constructed a new database containing 27 PVMs [acm, scm, sgrA, ecbA, fnm, sagA, hylEfm, ptsD, orf1481, fms15, fms21-fms20 (pili gene cluster 1, PGC-1), fms14-fms17-fms13 (PGC-2), empA-empB-empC (PGC-3), fms11-fms19-fms16 (PGC-4), ccpA, bepA, gls20-glsB1, and gls33-glsB] from nine reference genomes (seven Efm + two Elts). The database was validated against these reference genomes and further evaluated using a collection of well-characterized Efm (n = 43) and Elts (n = 7) control strains, by assessing PVM presence/absence and its variants together with a genomic phylogeny constructed as single-nucleotide polymorphisms. We found a high concordance between the phylogeny and in silico findings of the PVM, with Elts clustering separately and mostly carrying Elts-specific PVM gene variants. Based on our validation results, we recommend using the database with raw reads instead of assemblies to avoid missing gene variants. This newly constructed database of 27 PVMs will enable a more comprehensive characterization of Efm and Elts based on WGS data. The developed database exhibits scalability and boasts a range of applications in public health, including diagnostics, outbreak investigations, and epidemiological studies. It can be further used in risk assessment for distinguishing between safe and unsafe enterococci.IMPORTANCEThe newly constructed database, consisting of 27 putative virulence markers, is highly scalable and serves as a valuable resource for the comprehensive characterization of these closely related species using WGS data. It holds significant potential for various public health applications, including hospital outbreak investigations, surveillance, and risk assessment for probiotics and feed additives.
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Affiliation(s)
- Louise Roer
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Hülya Kaya
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Ana P. Tedim
- Group for Biomedical Research in Sepsis (BioSepsis), Instituto de Investigación Biomédica de Salamanca, Salamanca, Spain
- Grupo de Investigación Biomédica en Sepsis-BioSepsis, Hospital Universitario Río Hortega, Instituto de Investigación Biomédica de Salamanca (IBSAL), Valladollid, Spain
| | - Carla Novais
- UCIBIO, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Associate Laboratory i4HB, Faculty of Pharmacy, University of Porto, Institute for Health and Bioeconomy, Porto, Portugal
| | - Teresa M. Coque
- Department of Microbiology, Ramón y Cajal University Hospital and Ramón y Cajal Health Research Institute (IRYCIS), Madrid, Spain
- Network Research Centre for Infectious Diseases (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Frank M. Aarestrup
- Research Group for Genomic Epidemiology, Technical University of Denmark, National Food Institute, Lyngby, Denmark
| | - Luísa Peixe
- UCIBIO, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Associate Laboratory i4HB, Faculty of Pharmacy, University of Porto, Institute for Health and Bioeconomy, Porto, Portugal
| | - Henrik Hasman
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Anette M. Hammerum
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Ana R. Freitas
- UCIBIO, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Associate Laboratory i4HB, Faculty of Pharmacy, University of Porto, Institute for Health and Bioeconomy, Porto, Portugal
- 1H-TOXRUN—One Health Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, Gandra, Portugal
| | - On behalf of the ESCMID Study Group for Epidemiological Markers (ESGEM)
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
- Group for Biomedical Research in Sepsis (BioSepsis), Instituto de Investigación Biomédica de Salamanca, Salamanca, Spain
- Grupo de Investigación Biomédica en Sepsis-BioSepsis, Hospital Universitario Río Hortega, Instituto de Investigación Biomédica de Salamanca (IBSAL), Valladollid, Spain
- UCIBIO, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Associate Laboratory i4HB, Faculty of Pharmacy, University of Porto, Institute for Health and Bioeconomy, Porto, Portugal
- Department of Microbiology, Ramón y Cajal University Hospital and Ramón y Cajal Health Research Institute (IRYCIS), Madrid, Spain
- Network Research Centre for Infectious Diseases (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
- Research Group for Genomic Epidemiology, Technical University of Denmark, National Food Institute, Lyngby, Denmark
- 1H-TOXRUN—One Health Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, Gandra, Portugal
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AL Rubaye M, Janice J, Bjørnholt JV, Kacelnik O, Haldorsen BC, Nygaard RM, Hegstad J, Sundsfjord A, Hegstad K. The population structure of vancomycin-resistant and -susceptible Enterococcus faecium in a low-prevalence antimicrobial resistance setting is highly influenced by circulating global hospital-associated clones. Microb Genom 2023; 9:001160. [PMID: 38112685 PMCID: PMC10763505 DOI: 10.1099/mgen.0.001160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 12/01/2023] [Indexed: 12/21/2023] Open
Abstract
Between 2010 and 2015 the incidence of vancomycin-resistant Enterococcus faecium (VREfm) in Norway increased dramatically. Hence, we selected (1) a random subset of vancomycin-resistant enterococci (VRE) from the Norwegian Surveillance System for Communicable Diseases (2010-15; n=239) and (2) Norwegian vancomycin-susceptible E. faecium (VSEfm) bacteraemia isolates from the national surveillance system for antimicrobial resistance in microbes (2008 and 2014; n=261) for further analysis. Whole-genome sequences were collected for population structure, van gene cluster, mobile genetic element and virulome analysis, as well as antimicrobial susceptibility testing. Comparative genomic and phylogeographical analyses were performed with complete genomes of global E. faecium strains from the National Center for Biotechnology Information (NCBI) (1946-2022; n=272). All Norwegian VREfm and most of the VSEfm clustered with global hospital-associated sequence types (STs) in the phylogenetic subclade A1. The vanB2 subtype carried by chromosomal Tn1549 integrative conjugative elements was the dominant van type. The major Norwegian VREfm cluster types (CTs) were in accordance with concurrent European CTs. The dominant vanB-type VREfm CTs, ST192-CT3/26 and ST117-CT24, were mostly linked to a single hospital in Norway where the clones spread after independent chromosomal acquisition of Tn1549. The less prevalent vanA VRE were associated with more diverse CTs and vanA carrying Inc18 or RepA_N plasmids with toxin-antitoxin systems. Only 5 % of the Norwegian VRE were Enterococcus faecalis, all of which contained vanB. The Norwegian VREfm and VSEfm isolates harboured CT-specific virulence factor (VF) profiles supporting biofilm formation and colonization. The dominant VREfm CTs in general hosted more virulence determinants than VSEfm. The phylogenetic clade B VSEfm isolates (n=21), recently classified as Enterococcus lactis, harboured fewer VFs than E. faecium in general, and particularly subclade A1 isolates. In conclusion, the population structure of Norwegian E. faecium isolates mirrors the globally prevalent clones and particularly concurrent European VREfm/VSEfm CTs. Novel chromosomal acquisition of vanB2 on Tn1549 from the gut microbiota, however, formed a single major hospital VREfm outbreak. Dominant VREfm CTs contained more VFs than VSEfm.
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Affiliation(s)
- Mushtaq AL Rubaye
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Jessin Janice
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
- Present address: Section for development, Department of Microbiology, Clinic for Laboratory Medicine, Oslo University Hospital, Oslo, Norway
| | - Jørgen Vildershøj Bjørnholt
- Department of Clinical Microbiology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Oliver Kacelnik
- Department of Antibiotic Resistance and Infection Prevention, Norwegian Institute of Public Health, Oslo, Norway
| | - Bjørg C. Haldorsen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Randi M. Nygaard
- Department of Microbiology, Haukeland University Hospital, Bergen, Norway
| | - Joachim Hegstad
- Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Arnfinn Sundsfjord
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Kristin Hegstad
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - the Norwegian VRE study group
- Research group for Host–Microbe Interactions, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
- Department of Clinical Microbiology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Antibiotic Resistance and Infection Prevention, Norwegian Institute of Public Health, Oslo, Norway
- Department of Microbiology, Haukeland University Hospital, Bergen, Norway
- Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
- Present address: Section for development, Department of Microbiology, Clinic for Laboratory Medicine, Oslo University Hospital, Oslo, Norway
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5
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Gopalakrishna KP, Hillebrand GH, Bhavana VH, Elder JL, D'Mello A, Tettelin H, Hooven TA. Group B Streptococcus Cas9 variants provide insight into programmable gene repression and CRISPR-Cas transcriptional effects. Commun Biol 2023; 6:620. [PMID: 37296208 PMCID: PMC10256743 DOI: 10.1038/s42003-023-04994-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Group B Streptococcus (GBS; S. agalactiae) causes chorioamnionitis, neonatal sepsis, and can also cause disease in healthy or immunocompromised adults. GBS possesses a type II-A CRISPR-Cas9 system, which defends against foreign DNA within the bacterial cell. Several recent publications have shown that GBS Cas9 influences genome-wide transcription through a mechanism uncoupled from its function as a specific, RNA-programmable endonuclease. We examine GBS Cas9 effects on genome-wide transcription through generation of several isogenic variants with specific functional defects. We compare whole-genome RNA-seq from Δcas9 GBS with a full-length Cas9 gene deletion; dcas9 defective in its ability to cleave DNA but still able to bind to frequently occurring protospacer adjacent motifs; and scas9 that retains its catalytic domains but is unable to bind protospacer adjacent motifs. Comparing scas9 GBS to the other variants, we identify nonspecific protospacer adjacent motif binding as a driver of genome-wide, Cas9 transcriptional effects in GBS. We also show that Cas9 transcriptional effects from nonspecific scanning tend to influence genes involved in bacterial defense and nucleotide or carbohydrate transport and metabolism. While genome-wide transcription effects are detectable by analysis of next-generation sequencing, they do not result in virulence changes in a mouse model of sepsis. We also demonstrate that catalytically inactive dCas9 expressed from the GBS chromosome can be used with a straightforward, plasmid-based, single guide RNA expression system to suppress transcription of specific GBS genes without potentially confounding off-target effects. We anticipate that this system will be useful for study of nonessential and essential gene roles in GBS physiology and pathogenesis.
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Affiliation(s)
| | - Gideon H Hillebrand
- University of Pittsburgh School of Medicine, Program in Microbiology and Immunology, Pittsburgh, PA, USA
| | - Venkata H Bhavana
- University of Pittsburgh School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
| | - Jordan L Elder
- The Cleveland Clinic, Clinical Laboratory Services, Cleveland, OH, USA
| | - Adonis D'Mello
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hervé Tettelin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Thomas A Hooven
- University of Pittsburgh School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA.
- Richard King Mellon Institute for Pediatric Research, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
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6
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Gopalakrishna KP, Hillebrand GH, Bhavana VH, Elder JL, D'Mello A, Tettelin H, Hooven TA. Group B Streptococcus Cas9 variants provide insight into programmable gene repression and CRISPR-Cas transcriptional effects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.24.542094. [PMID: 37292749 PMCID: PMC10245859 DOI: 10.1101/2023.05.24.542094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Group B Streptococcus (GBS; S. agalactiae ) causes chorioamnionitis, neonatal sepsis, and can also cause disease in healthy or immunocompromised adults. GBS possesses a type II-A CRISPR-Cas9 system, which defends against foreign DNA within the bacterial cell. Several recent publications have shown that GBS Cas9 influences genome-wide transcription through a mechanism uncoupled from its function as a specific, RNA-programmable endonuclease. We examine GBS Cas9 effects on genome-wide transcription through generation of several isogenic variants with specific functional defects. We compare whole-genome RNA-seq from Δ cas9 GBS with a full-length Cas9 gene deletion; dcas9 defective in its ability to cleave DNA but still able to bind to frequently occurring protospacer adjacent motifs; and scas9 that retains its catalytic domains but is unable to bind protospacer adjacent motifs. Comparing scas9 GBS to the other variants, we identify nonspecific protospacer adjacent motif binding as a driver of genome-wide, Cas9 transcriptional effects in GBS. We also show that Cas9 transcriptional effects from nonspecific scanning tend to influence genes involved in bacterial defense and nucleotide or carbohydrate transport and metabolism. While genome-wide transcription effects are detectable by analysis of next-generation sequencing, they do not result in virulence changes in a mouse model of sepsis. We also demonstrate that catalytically inactive dCas9 expressed from the GBS chromosome can be used with a straightforward, plasmid-based, single guide RNA expression system to suppress transcription of specific GBS genes without potentially confounding off-target effects. We anticipate that this system will be useful for study of nonessential and essential gene roles in GBS physiology and pathogenesis.
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7
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Revtovich AV, Tjahjono E, Singh KV, Hanson BM, Murray BE, Kirienko NV. Development and Characterization of High-Throughput Caenorhabditis elegans - Enterococcus faecium Infection Model. Front Cell Infect Microbiol 2021; 11:667327. [PMID: 33996637 PMCID: PMC8116795 DOI: 10.3389/fcimb.2021.667327] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/13/2021] [Indexed: 12/16/2022] Open
Abstract
The genus Enterococcus includes two Gram-positive pathogens of particular clinical relevance: E. faecalis and E. faecium. Infections with each of these pathogens are becoming more frequent, particularly in the case of hospital-acquired infections. Like most other bacterial species of clinical importance, antimicrobial resistance (and, specifically, multi-drug resistance) is an increasing threat, with both species considered to be of particular importance by the World Health Organization and the US Centers for Disease Control. The threat of antimicrobial resistance is exacerbated by the staggering difference in the speeds of development for the discovery and development of the antimicrobials versus resistance mechanisms. In the search for alternative strategies, modulation of host-pathogen interactions in general, and virulence inhibition in particular, have drawn substantial attention. Unfortunately, these approaches require a fairly comprehensive understanding of virulence determinants. This requirement is complicated by the fact that enterococcal infection models generally require vertebrates, making them slow, expensive, and ethically problematic, particularly when considering the thousands of animals that would be needed for the early stages of experimentation. To address this problem, we developed the first high-throughput C. elegans-E. faecium infection model involving host death. Importantly, this model recapitulates many key aspects of murine peritonitis models, including utilizing similar virulence determinants. Additionally, host death is independent of peroxide production, unlike other E. faecium-C. elegans virulence models, which allows the assessment of other virulence factors. Using this system, we analyzed a panel of lab strains with deletions of targeted virulence factors. Although removal of certain virulence factors (e.g., Δfms15) was sufficient to affect virulence, multiple deletions were generally required to affect pathogenesis, suggesting that host-pathogen interactions are multifactorial. These data were corroborated by genomic analysis of selected isolates with high and low levels of virulence. We anticipate that this platform will be useful for identifying new treatments for E. faecium infection.
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Affiliation(s)
| | - Elissa Tjahjono
- Department of BioSciences, Rice University, Houston, TX, United States
| | - Kavindra V. Singh
- Division of Infectious Diseases, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
| | - Blake M. Hanson
- Division of Infectious Diseases, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
- Center for Infectious Diseases, School of Public Health, University of Texas Health Science Center, Houston, TX, United States
| | - Barbara E. Murray
- Division of Infectious Diseases, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
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Thurlow LR, Stephens AC, Hurley KE, Richardson AR. Lack of nutritional immunity in diabetic skin infections promotes Staphylococcus aureus virulence. SCIENCE ADVANCES 2020; 6:6/46/eabc5569. [PMID: 33188027 PMCID: PMC7673755 DOI: 10.1126/sciadv.abc5569] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 09/29/2020] [Indexed: 05/22/2023]
Abstract
Elevated blood/tissue glucose is a hallmark feature of advanced diabetes, and people with diabetes are prone to more frequent and invasive infections with Staphylococcus aureus. Phagocytes must markedly increase glucose consumption during infection to generate and oxidative burst and kill invading bacteria. Similarly, glucose is essential for S. aureus survival in an infection and competition with the host, for this limited resource is reminiscent of nutritional immunity. Here, we show that infiltrating phagocytes do not express their high-efficiency glucose transporters in modeled diabetic infections, resulting in a diminished respiratory burst and increased glucose availability for S. aureus We show that excess glucose in these hyperglycemic abscesses significantly enhances S. aureus virulence potential, resulting in worse infection outcomes. Last, we show that two glucose transporters recently acquired by S. aureus are essential for excess virulence factor production and the concomitant increase in disease severity in hyperglycemic infections.
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Affiliation(s)
- Lance R Thurlow
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Amelia C Stephens
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Kelly E Hurley
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Anthony R Richardson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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9
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de Maat V, Stege PB, Dedden M, Hamer M, van Pijkeren JP, Willems RJL, van Schaik W. CRISPR-Cas9-mediated genome editing in vancomycin-resistant Enterococcus faecium. FEMS Microbiol Lett 2020; 366:5697197. [PMID: 31905238 PMCID: PMC9189978 DOI: 10.1093/femsle/fnz256] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/03/2020] [Indexed: 12/29/2022] Open
Abstract
The Gram-positive bacterium Enterococcus faecium is becoming increasingly prevalent as a cause of hospital-acquired, antibiotic-resistant infections. A fundamental part of research into E. faecium biology relies on the ability to generate targeted mutants but this process is currently labour-intensive and time-consuming, taking 4 to 5 weeks per mutant. In this report, we describe a method relying on the high recombination rates of E. faecium and the application of the Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-Cas9 genome editing tool to more efficiently generate targeted mutants in the E. faecium chromosome. Using this tool and the multi-drug resistant clinical E. faecium strain E745, we generated a deletion mutant in the lacL gene, which encodes the large subunit of the E. faeciumβ-galactosidase. Blue/white screening using 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) could be used to distinguish between the wild-type and lacL deletion mutant. We also inserted two copies of gfp into the intrinsic E. faecium macrolide resistance gene msrC to generate stable green fluorescent cells. We conclude that CRISPR-Cas9 can be used to generate targeted genome modifications in E. faecium in 3 weeks, with limited hands-on time. This method can potentially be implemented in other Gram-positive bacteria with high intrinsic recombination rates.
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Affiliation(s)
- Vincent de Maat
- Department of Medical Microbiology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Paul B Stege
- Department of Medical Microbiology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Mark Dedden
- Department of Medical Microbiology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Maud Hamer
- Department of Medical Microbiology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Jan-Peter van Pijkeren
- Department of Food Science, A203B Babcock Hall, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Rob J L Willems
- Department of Medical Microbiology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Willem van Schaik
- Department of Medical Microbiology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
- Institute of Microbiology and Infection, Biosciences building, University of Birmingham, Birmingham B15 2TT, UK
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10
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Bai Y, Shang M, Xu M, Wu A, Sun L, Zheng L. Transcriptome, Phenotypic, and Virulence Analysis of Streptococcus sanguinis SK36 Wild Type and Its CcpA-Null Derivative (ΔCcpA). Front Cell Infect Microbiol 2019; 9:411. [PMID: 31867286 PMCID: PMC6904348 DOI: 10.3389/fcimb.2019.00411] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 11/19/2019] [Indexed: 12/15/2022] Open
Abstract
Catabolic control protein (CcpA) is linked to complex carbohydrate utilization and virulence factor in many bacteria species, influences the transcription of target genes by many mechanisms. To characterize the activity and regulatory mechanisms of CcpA in Streptococcus sanguinis, here, we analyzed the transcriptome of Streptococcus sanguinis SK36 and its CcpA-null derivative (ΔCcpA) using RNA-seq. Compared to the regulon of CcpA in SK36 in the RegPrecise database, we found that only minority of differentially expressed genes (DEGs) contained putative catabolite response element (cre) in their regulatory regions, indicating that many genes could have been affected indirectly by the loss of CcpA and analyzing the sequence of the promoter region using prediction tools is not a desirable method to recognize potential target genes of global regulator CcpA. Gene ontology and pathway analysis of DEGs revealed that CcpA exerts an influence predominantly involved in carbon catabolite metabolism and some amino acid catabolite pathways, which has been linked to expression of virulence genes in many pathogens and coordinately regulate the disease progression in vivo studies. However, in some scenarios, differences observed at the transcript level could not reflect the real differences at the protein level. Therefore, to confirm the differences in phenotype and virulence of SK36 and ΔCcpA, we characterized the role of CcpA in the regulation of biofilm development, EPS production and the virulence of Streptococcus sanguinis. Results showed CcpA inactivation impaired biofilm and EPS formation, and CcpA also involved in virulence in rabbit infective endocarditis model. These findings will undoubtedly contribute to investigate the mechanistic links between the global regulator CcpA and the virulence of Streptococcus sanguinis, further broaden our understanding of the relationship between basic metabolic processes and virulence.
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Affiliation(s)
- Yibo Bai
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Mengmeng Shang
- Department of Scientific Research, Peking Union Medical College Hospital (East), Beijing, China
| | - Mengya Xu
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Anyi Wu
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Luning Sun
- Department of Pathophysiology, College of Basic Medical Science, China Medical University, Shenyang, China
| | - Lanyan Zheng
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, China
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11
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Abstract
The study of the genetics of enterococci has focused heavily on mobile genetic elements present in these organisms, the complex regulatory circuits used to control their mobility, and the antibiotic resistance genes they frequently carry. Recently, more focus has been placed on the regulation of genes involved in the virulence of the opportunistic pathogenic species Enterococcus faecalis and Enterococcus faecium. Little information is available concerning fundamental aspects of DNA replication, partition, and division; this article begins with a brief overview of what little is known about these issues, primarily by comparison with better-studied model organisms. A variety of transcriptional and posttranscriptional mechanisms of regulation of gene expression are then discussed, including a section on the genetics and regulation of vancomycin resistance in enterococci. The article then provides extensive coverage of the pheromone-responsive conjugation plasmids, including sections on regulation of the pheromone response, the conjugative apparatus, and replication and stable inheritance. The article then focuses on conjugative transposons, now referred to as integrated, conjugative elements, or ICEs, and concludes with several smaller sections covering emerging areas of interest concerning the enterococcal mobilome, including nonpheromone plasmids of particular interest, toxin-antitoxin systems, pathogenicity islands, bacteriophages, and genome defense.
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12
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Enterococcus faecium TIR-Domain Genes Are Part of a Gene Cluster Which Promotes Bacterial Survival in Blood. Int J Microbiol 2019; 2018:1435820. [PMID: 30631364 PMCID: PMC6304867 DOI: 10.1155/2018/1435820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/14/2018] [Indexed: 11/29/2022] Open
Abstract
Enterococcus faecium has undergone a transition to a multidrug-resistant nosocomial pathogen. The population structure of E. faecium is characterized by a sharp distinction of clades, where the hospital-adapted lineage is primarily responsible for bacteremia. So far, factors that were identified in hospital-adapted strains and that promoted pathogenesis of nosocomial E. faecium mainly play a role in adherence and biofilm production, while less is known about factors contributing to survival in blood. This study identified a gene cluster, which includes genes encoding bacterial Toll/interleukin-1 receptor- (TIR-) domain-containing proteins (TirEs). The cluster was found to be unique to nosocomial strains and to be located on a putative mobile genetic element of phage origin. The three genes within the cluster appeared to be expressed as an operon. Expression was detected in bacterial culture media and in the presence of human blood. TirEs are released into the bacterial supernatant, and TirE2 is associated with membrane vesicles. Furthermore, the tirE-gene cluster promotes bacterial proliferation in human blood, indicating that TirE may contribute to the pathogenesis of bacteremia.
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13
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Paluscio E, Watson ME, Caparon MG. CcpA Coordinates Growth/Damage Balance for Streptococcus pyogenes Pathogenesis. Sci Rep 2018; 8:14254. [PMID: 30250043 PMCID: PMC6155242 DOI: 10.1038/s41598-018-32558-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/30/2018] [Indexed: 12/22/2022] Open
Abstract
To achieve maximum fitness, pathogens must balance growth with tissue damage, coordinating metabolism and virulence factor expression. In the gram-positive bacterium Streptococcus pyogenes, the DNA-binding transcriptional regulator Carbon Catabolite Protein A (CcpA) is a master regulator of both carbon catabolite repression and virulence, suggesting it coordinates growth/damage balance. To examine this, two murine models were used to compare the virulence of a mutant lacking CcpA with a mutant expressing CcpA locked into its high-affinity DNA-binding conformation (CcpAT307Y). In models of acute soft tissue infection and of long-term asymptomatic mucosal colonization, both CcpA mutants displayed altered virulence, albeit with distinct growth/damage profiles. Loss of CcpA resulted in a diminished ability to grow in tissue, leading to less damage and early clearance. In contrast, constitutive DNA-binding activity uncoupled the growth/damage relationship, such that high tissue burdens and extended time of carriage were achieved, despite reduced tissue damage. These data demonstrate that growth/damage balance can be actively controlled by the pathogen and implicate CcpA as a master regulator of this relationship. This suggests a model where the topology of the S. pyogenes virulence network has evolved to couple carbon source selection with growth/damage balance, which may differentially influence pathogenesis at distinct tissues.
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Affiliation(s)
- Elyse Paluscio
- Department of Molecular Microbiology, Washington University School of Medicine St Louis, St. Louis, MO, 63110-1093, United States
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15219, United States
| | - Michael E Watson
- Department of Molecular Microbiology, Washington University School of Medicine St Louis, St. Louis, MO, 63110-1093, United States
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, 48109-5624, United States
| | - Michael G Caparon
- Department of Molecular Microbiology, Washington University School of Medicine St Louis, St. Louis, MO, 63110-1093, United States.
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14
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Enterococcus faecium produces membrane vesicles containing virulence factors and antimicrobial resistance related proteins. J Proteomics 2018; 187:28-38. [DOI: 10.1016/j.jprot.2018.05.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/25/2018] [Accepted: 05/29/2018] [Indexed: 11/19/2022]
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15
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Goh HMS, Yong MHA, Chong KKL, Kline KA. Model systems for the study of Enterococcal colonization and infection. Virulence 2017; 8:1525-1562. [PMID: 28102784 PMCID: PMC5810481 DOI: 10.1080/21505594.2017.1279766] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/30/2016] [Accepted: 01/04/2017] [Indexed: 02/07/2023] Open
Abstract
Enterococcus faecalis and Enterococcus faecium are common inhabitants of the human gastrointestinal tract, as well as frequent opportunistic pathogens. Enterococci cause a range of infections including, most frequently, infections of the urinary tract, catheterized urinary tract, bloodstream, wounds and surgical sites, and heart valves in endocarditis. Enterococcal infections are often biofilm-associated, polymicrobial in nature, and resistant to antibiotics of last resort. Understanding Enterococcal mechanisms of colonization and pathogenesis are important for identifying new ways to manage and intervene with these infections. We review vertebrate and invertebrate model systems applied to study the most common E. faecalis and E. faecium infections, with emphasis on recent findings examining Enterococcal-host interactions using these models. We discuss strengths and shortcomings of each model, propose future animal models not yet applied to study mono- and polymicrobial infections involving E. faecalis and E. faecium, and comment on the significance of anti-virulence strategies derived from a fundamental understanding of host-pathogen interactions in model systems.
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Affiliation(s)
- H. M. Sharon Goh
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - M. H. Adeline Yong
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kelvin Kian Long Chong
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Interdisciplinary Graduate School, Nanyang Technological University, Singapore
| | - Kimberly A. Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
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16
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Miller WR, Murray BE, Rice LB, Arias CA. Vancomycin-Resistant Enterococci: Therapeutic Challenges in the 21st Century. Infect Dis Clin North Am 2017; 30:415-439. [PMID: 27208766 DOI: 10.1016/j.idc.2016.02.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Vancomycin-resistant enterococci are serious health threats due in part to their ability to persist in rugged environments and their propensity to acquire antibiotic resistance determinants. Enterococci have now established a home in our hospitals and possess mechanisms to defeat most currently available antimicrobials. This article reviews the history of the struggle with this pathogen, what is known about the traits associated with its rise in the modern medical environment, and the current understanding of therapeutic approaches in severe infections caused by these microorganisms. As the 21st century progresses, vancomycin-resistant enterococci continue to pose a daunting clinical challenge.
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Affiliation(s)
- William R Miller
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Barbara E Murray
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA; Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Louis B Rice
- Departments of Medicine, Microbiology and Immunology, Warren Alpert Medical School of Brown University, 593 Eddy Street, Providence, RI 02903, USA
| | - Cesar A Arias
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA; Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA; Molecular Genetics and Antimicrobial Resistance Unit, International Center for Microbial Genomics, Universidad El Bosque, Avenue Cra 9 No. 131 A - 02, Bogotá, Colombia.
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17
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A Multi-Serotype Approach Clarifies the Catabolite Control Protein A Regulon in the Major Human Pathogen Group A Streptococcus. Sci Rep 2016; 6:32442. [PMID: 27580596 PMCID: PMC5007534 DOI: 10.1038/srep32442] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/04/2016] [Indexed: 12/20/2022] Open
Abstract
Catabolite control protein A (CcpA) is a highly conserved, master regulator of carbon source utilization in gram-positive bacteria, but the CcpA regulon remains ill-defined. In this study we aimed to clarify the CcpA regulon by determining the impact of CcpA-inactivation on the virulence and transcriptome of three distinct serotypes of the major human pathogen Group A Streptococcus (GAS). CcpA-inactivation significantly decreased GAS virulence in a broad array of animal challenge models consistent with the idea that CcpA is critical to gram-positive bacterial pathogenesis. Via comparative transcriptomics, we established that the GAS CcpA core regulon is enriched for highly conserved CcpA binding motifs (i.e. cre sites). Conversely, strain-specific differences in the CcpA transcriptome seems to consist primarily of affected secondary networks. Refinement of cre site composition via analysis of the core regulon facilitated development of a modified cre consensus that shows promise for improved prediction of CcpA targets in other medically relevant gram-positive pathogens.
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18
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Abstract
Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.
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19
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Paganelli FL, Huebner J, Singh KV, Zhang X, van Schaik W, Wobser D, Braat JC, Murray BE, Bonten MJM, Willems RJL, Leavis HL. Genome-wide Screening Identifies Phosphotransferase System Permease BepA to Be Involved in Enterococcus faecium Endocarditis and Biofilm Formation. J Infect Dis 2016; 214:189-95. [PMID: 26984142 DOI: 10.1093/infdis/jiw108] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/07/2016] [Indexed: 02/02/2023] Open
Abstract
Enterococcus faecium is a common cause of nosocomial infections, of which infective endocarditis is associated with substantial mortality. In this study, we used a microarray-based transposon mapping (M-TraM) approach to evaluate a rat endocarditis model and identified a gene, originally annotated as "fruA" and renamed "bepA," putatively encoding a carbohydrate phosphotransferase system (PTS) permease (biofilm and endocarditis-associated permease A [BepA]), as important in infective endocarditis. This gene is highly enriched in E. faecium clinical isolates and absent in commensal isolates that are not associated with infection. Confirmation of the phenotype was established in a competition experiment of wild-type and a markerless bepA mutant in a rat endocarditis model. In addition, deletion of bepA impaired biofilm formation in vitro in the presence of 100% human serum and metabolism of β-methyl-D-glucoside. β-glucoside metabolism has been linked to the metabolism of glycosaminoglycans that are exposed on injured heart valves, where bacteria attach and form vegetations. Therefore, we propose that the PTS permease BepA is directly implicated in E. faecium pathogenesis.
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Affiliation(s)
- Fernanda L Paganelli
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
| | - Johannes Huebner
- Division of Pediatric Infectious Diseases, Hauner Children's Hospital, Ludwigs-Maximilian Universität München Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Germany
| | - Kavindra V Singh
- Department of Internal Medicine, Division of Infectious Diseases Center for the Study of Emerging and Re-emerging Pathogens
| | - Xinglin Zhang
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
| | - Willem van Schaik
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
| | - Dominique Wobser
- Center for Infectious Disease and Travel Medicine, University Medical Center Freiburg, Germany
| | - Johanna C Braat
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
| | - Barbara E Murray
- Department of Internal Medicine, Division of Infectious Diseases Center for the Study of Emerging and Re-emerging Pathogens Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston
| | - Marc J M Bonten
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
| | - Rob J L Willems
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
| | - Helen L Leavis
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
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20
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The fibronectin-binding protein Fnm contributes to adherence to extracellular matrix components and virulence of Enterococcus faecium. Infect Immun 2015; 83:4653-61. [PMID: 26371130 DOI: 10.1128/iai.00885-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/10/2015] [Indexed: 12/29/2022] Open
Abstract
The interaction between bacteria and fibronectin is believed to play an important role in the pathogenicity of clinically important Gram-positive cocci. In the present study, we identified a gene encoding a predicted fibronectin-binding protein of Enterococcus faecium (fnm), a homologue of Streptococcus pneumoniae pavA, in the genomes of E. faecium strain TX82 and all other sequenced E. faecium isolates. Full-length recombinant Fnm from strain TX82 bound to immobilized fibronectin in a concentration-dependent manner and also appeared to bind collagen type V and laminin, but not other proteins, such as transferrin, heparin, bovine serum albumin, mucin, or collagen IV. We demonstrated that the N-terminal fragment of Fnm is required for full fibronectin binding, since truncation of this region caused a 2.4-fold decrease (P < 0.05) in the adhesion of E. faecium TX82 to fibronectin. Deletion of fnm resulted in a significant reduction (P < 0.001) in the ability of the mutant, TX6128, to bind fibronectin relative to that of the wild-type strain; in situ reconstitution of fnm in the deletion mutant strain restored adherence. In addition, the Δfnm mutant was highly attenuated relative to TX82 (P ≤ 0.0001) in a mixed-inoculum rat endocarditis model. Taken together, these results demonstrate that Fnm affects the adherence of E. faecium to fibronectin and is important in the pathogenesis of experimental endocarditis.
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21
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Galloway-Peña JR, Liang X, Singh KV, Yadav P, Chang C, La Rosa SL, Shelburne S, Ton-That H, Höök M, Murray BE. The identification and functional characterization of WxL proteins from Enterococcus faecium reveal surface proteins involved in extracellular matrix interactions. J Bacteriol 2015; 197:882-92. [PMID: 25512313 PMCID: PMC4325096 DOI: 10.1128/jb.02288-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/10/2014] [Indexed: 11/20/2022] Open
Abstract
The WxL domain recently has been identified as a novel cell wall binding domain found in numerous predicted proteins within multiple Gram-positive bacterial species. However, little is known about the function of proteins containing this novel domain. Here, we identify and characterize 6 Enterococcus faecium proteins containing the WxL domain which, by reverse transcription-PCR (RT-PCR) and genomic analyses, are located in three similarly organized operons, deemed WxL loci A, B, and C. Western blotting, electron microscopy, and enzyme-linked immunosorbent assays (ELISAs) determined that genes of WxL loci A and C encode antigenic, cell surface proteins exposed at higher levels in clinical isolates than in commensal isolates. Secondary structural analyses of locus A recombinant WxL domain-containing proteins found they are rich in β-sheet structure and disordered segments. Using Biacore analyses, we discovered that recombinant WxL proteins from locus A bind human extracellular matrix proteins, specifically type I collagen and fibronectin. Proteins encoded by locus A also were found to bind to each other, suggesting a novel cell surface complex. Furthermore, bile salt survival assays and animal models using a mutant from which all three WxL loci were deleted revealed the involvement of WxL operons in bile salt stress and endocarditis pathogenesis. In summary, these studies extend our understanding of proteins containing the WxL domain and their potential impact on colonization and virulence in E. faecium and possibly other Gram-positive bacterial species.
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Affiliation(s)
- Jessica R Galloway-Peña
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Health Science Center, Houston, Texas, USA
| | - Xiaowen Liang
- Center for Infectious and Inflammatory Diseases, Institute for Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas, USA
| | - Kavindra V Singh
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Health Science Center, Houston, Texas, USA
| | - Puja Yadav
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Health Science Center, Houston, Texas, USA
| | - Chungyu Chang
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA
| | - Sabina Leanti La Rosa
- Department of Chemistry, Biotechnology and Food Science, Laboratory of Microbial Gene Technology and Food Microbiology, The Norwegian University of Life Sciences, Aas, Norway
| | - Samuel Shelburne
- Department of Infectious Diseases, Infection Control and Employee Health, M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Hung Ton-That
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA
| | - Magnus Höök
- Center for Infectious and Inflammatory Diseases, Institute for Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas, USA
| | - Barbara E Murray
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas, USA Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Health Science Center, Houston, Texas, USA
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