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Zhu L, Yang X, Fu X, Yang P, Lin X, Wang F, Shen Z, Wang J, Sun F, Qiu Z. Pheromone cCF10 inhibits the antibiotic persistence of Enterococcus faecalis by modulating energy metabolism. Front Microbiol 2024; 15:1408701. [PMID: 39040910 PMCID: PMC11260814 DOI: 10.3389/fmicb.2024.1408701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/24/2024] [Indexed: 07/24/2024] Open
Abstract
Introduction Bacterial resistance presents a major challenge to both the ecological environment and human well-being, with persistence playing a key role. Multiple studies were recently undertaken to examine the factors influencing the formation of persisters and the underlying process, with a primary focus on Gram-negative bacteria and Staphylococcus aureus (Gram-positive bacteria). Enterococcus faecalis (E. faecalis) is capable of causing a variety of infectious diseases, but there have been few studies of E. faecalis persisters. Previous studies have shown that the sex pheromone cCF10 secreted by E. faecalis induces conjugative plasmid transfer. However, whether the pheromone cCF10 regulates the persistence of E. faecalis has not been investigated. Methods As a result, we investigated the effect and potential molecular mechanism of pheromone cCF10 in regulating the formation of persisters in E. faecalis OG1RF using a persistent bacteria model. Results and discussion The metabolically active E. faecalis OG1RF reached a persistence state and temporarily tolerated lethal antibiotic concentrations after 8 h of levofloxacin hydrochloride (20 mg/mL) exposure, exhibiting a persistence rate of 0.109 %. During the growth of E. faecalis OG1RF, biofilm formation was a critical factor contributing to antibiotic persistence, whereas 10 ng/mL cCF10 blocked persister cell formation. Notably, cCF10 mediated the antibiotic persistence of E. faecalis OG1RF via regulating metabolic activity rather than suppressing biofilm formation. The addition of cCF10 stimulated the Opp system and entered bacterial cells, inhibiting (p)ppGpp accumulation, thus maintaining the metabolically active state of bacteria and reducing persister cell generation. These findings offer valuable insights into the formation, as well as the control mechanism of E. faecalis persisters.
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Affiliation(s)
- Li Zhu
- School of Environmental and Chemical Engineering, Xi’an Polytechnic University, Xi’an, China
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Xiaobo Yang
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Xinyue Fu
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai, China
| | - Panpan Yang
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
- School of Public Health, North China University of Science and Technology, Tangshan, China
| | - Xiaoli Lin
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
- Key Laboratory of Karst Geological Resources and Environment, Guizhou University, Guizhou, China
| | - Feng Wang
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai, China
| | - Zhiqiang Shen
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Jingfeng Wang
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Feilong Sun
- School of Environmental and Chemical Engineering, Xi’an Polytechnic University, Xi’an, China
| | - Zhigang Qiu
- Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
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Shah D, Varahan S. Enterococcus faecalis. Trends Microbiol 2024:S0966-842X(24)00095-7. [PMID: 38762335 DOI: 10.1016/j.tim.2024.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/20/2024]
Affiliation(s)
- Dhrumi Shah
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sriram Varahan
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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3
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Kristensen SS, Diep DB, Kjos M, Mathiesen G. The role of site-2-proteases in bacteria: a review on physiology, virulence, and therapeutic potential. MICROLIFE 2023; 4:uqad025. [PMID: 37223736 PMCID: PMC10202637 DOI: 10.1093/femsml/uqad025] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/21/2023] [Accepted: 05/02/2023] [Indexed: 05/25/2023]
Abstract
Site-2-proteases are a class of intramembrane proteases involved in regulated intramembrane proteolysis. Regulated intramembrane proteolysis is a highly conserved signaling mechanism that commonly involves sequential digestion of an anti-sigma factor by a site-1- and site-2-protease in response to external stimuli, resulting in an adaptive transcriptional response. Variation of this signaling cascade continues to emerge as the role of site-2-proteases in bacteria continues to be explored. Site-2-proteases are highly conserved among bacteria and play a key role in multiple processes, including iron uptake, stress response, and pheromone production. Additionally, an increasing number of site-2-proteases have been found to play a pivotal role in the virulence properties of multiple human pathogens, such as alginate production in Pseudomonas aeruginosa, toxin production in Vibrio cholerae, resistance to lysozyme in enterococci and antimicrobials in several Bacillus spp, and cell-envelope lipid composition in Mycobacterium tuberculosis. The prominent role of site-2-proteases in bacterial pathogenicity highlights the potential of site-2-proteases as novel targets for therapeutic intervention. In this review, we summarize the role of site-2-proteases in bacterial physiology and virulence, as well as evaluate the therapeutic potential of site-2-proteases.
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Affiliation(s)
- Sofie S Kristensen
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), 1433 Ås, Norway
| | | | - Morten Kjos
- Corresponding author. NMBU, P.O. Box 5003, 1433 Ås, Norway. E-mail:
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Yang Y, Yang X, Zhou H, Niu Y, Li J, Fu X, Wang S, Xue B, Li C, Zhao C, Zhang X, Shen Z, Wang J, Qiu Z. Bisphenols Promote the Pheromone-Responsive Plasmid-Mediated Conjugative Transfer of Antibiotic Resistance Genes in Enterococcus faecalis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17653-17662. [PMID: 36445841 DOI: 10.1021/acs.est.2c05349] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The enrichment and spread of antibiotic resistance genes (ARGs) induced by environmental chemical pollution further exacerbated the threat to human health and ecological safety. Several compounds are known to induce R plasmid-mediated conjugation through inducing reactive oxygen species (ROS), increasing cell membrane permeability, enhancing regulatory genes expression, and so forth. Up to now, there has been no substantial breakthrough in the studies of models and related mechanisms. Here, we established a new conjugation model using pheromone-responsive plasmid pCF10 and confirmed that five kinds of bisphenols (BPs) at environmentally relevant concentrations could significantly promote the conjugation of ARGs mediated by plasmid pCF10 in E. faecalis by up to 4.5-fold compared with untreated cells. Using qPCR, gene knockout and UHPLC, we explored the mechanisms behind this phenomenon using bisphenol A (BPA) as a model of BPs and demonstrated that BPA could upregulate the expression of pheromone, promote bacterial aggregation, and even directly activate conjugation as a pheromone instead of producing ROS and enhancing cell membrane permeability. Interestingly, the result of mathematical analysis showed that the pheromone effect of most BPs is more potent than that of synthetic pheromone cCF10. These findings provide new insight into the environmental behavior and biological effect of BPs and provided new method and theory to study on enrichment and spread of ARGs induced by environmental chemical pollution.
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Affiliation(s)
- Yutong Yang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Xiaobo Yang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Hongrui Zhou
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Yuanyuan Niu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Shanghai Ocean University, Shanghai201306, China
| | - Jing Li
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Tianjin University of Traditional Chinese Medicine, Tianjin301617, China
| | - Xinyue Fu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
- Shanghai Ocean University, Shanghai201306, China
| | - Shang Wang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Bin Xue
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Chenyu Li
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Chen Zhao
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Xi Zhang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Zhiqiang Shen
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Jingfeng Wang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
| | - Zhigang Qiu
- Tianjin Institute of Environmental and Operational Medicine, Tianjin300050, China
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Santajit S, Sookrung N, Indrawattana N. Quorum Sensing in ESKAPE Bugs: A Target for Combating Antimicrobial Resistance and Bacterial Virulence. BIOLOGY 2022; 11:biology11101466. [PMID: 36290370 PMCID: PMC9598666 DOI: 10.3390/biology11101466] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/22/2022] [Accepted: 09/30/2022] [Indexed: 11/26/2022]
Abstract
A clique of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. (ESKAPE) bugs is the utmost causative agent responsible for multidrug resistance in hospital settings. These microorganisms employ a type of cell-cell communication termed 'quorum sensing (QS) system' to mediate population density and synchronously control the genes that modulate drug resistance and pathogenic behaviors. In this article, we focused on the present understanding of the prevailing QS system in ESKAPE pathogens. Basically, the QS component consisted of an autoinducer synthase, a ligand (e.g., acyl homoserine lactones/peptide hormones), and a transcriptional regulator. QS mediated expression of the bacterial capsule, iron acquisition, adherence factors, synthesis of lipopolysaccharide, poly-N-acetylglucosamine (PNAG) biosynthesis, motility, as well as biofilm development allow bacteria to promote an antimicrobial-resistant population that can escape the action of traditional drugs and endorse a divergent virulence production. The increasing prevalence of these harmful threats to infection control, as well as the urgent need for effective antimicrobial strategies to combat them, serve to highlight the important anti-QS strategies developed to address the difficulty of treating microorganisms.
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Affiliation(s)
- Sirijan Santajit
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Research Center in Tropical Pathobiology, Walailak University, Nakhon Si Thammarat 80160, Thailand
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Nitat Sookrung
- Biomedical Research Incubator Unit, Department of Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Nitaya Indrawattana
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
- Correspondence: ; Tel.: +66-2-354-9100 (ext. 1598)
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A bioanalytical screening method for Enterococcus faecalis RNPP-type quorum sensing peptides in murine feces. Bioanalysis 2022; 14:151-167. [PMID: 35014887 DOI: 10.4155/bio-2021-0225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: Bacteria coordinate their behavior as a group via communication with their peers, known as 'quorum sensing'. Enterococcus faecalis employs quorum sensing via RNPP-peptides which were not yet reported to be present in mammalian biofluids. Results: Solid phase extraction of murine feces was performed, followed by ultra high performance liquid chromatography (UHPLC-MS/MS) in multiple reaction monitoring (MRM) mode (in total <90 min/sample) for the nine known RNPP peptides. Limits of detection ranged between 0.045 and 52 nM. Adequate identification criteria allowed detection of RNPP quorum sensing peptides in 2/20 wild-type murine feces samples (i.e., cAM373 and cOB1). Conclusion: A fit-for-purpose UHPLC-MS/MS method detected these RNPP peptides in wild-type murine feces samples.
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7
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Conwell M, Dooley J, Naughton PJ. Enterococcal biofilm - a nidus for antibiotic resistance transfer? J Appl Microbiol 2022; 132:3444-3460. [PMID: 34990042 PMCID: PMC9306868 DOI: 10.1111/jam.15441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/03/2021] [Accepted: 01/03/2022] [Indexed: 11/30/2022]
Abstract
Enterococci, important agents of hospital acquired infection, are listed on the WHO list of multi-drug resistant pathogens commonly encountered in hospital acquired infections are now of increasing importance, due to the development of strains resistant to multiple antibiotics. Enterococci are also important microorganisms in the environment and their presence is frequently used as an indicator of faecal pollution. Their success is related to their ability to survive within a broad range of habitats and the ease by which they acquire mobile genetic elements, including plasmids, from other bacteria. The enterococci are frequently present within a bacterial biofilm which provides stability and protection to the bacterial population along with an opportunity for a variety of bacterial interactions. Enterococci can accept extrachromosomal DNA both from within its own species and from other bacterial species and this is enhanced by the proximity of the donor and recipient strains. It is this exchange of genetic material that makes the role of biofilm such an important aspect of the success of enterococci. There remain many questions regarding the most suitable model systems to study enterococci in biofilm and regarding the transfer of genetic material including antibiotic resistance in these biofilms. This review focuses on some important aspects of biofilm in the context of horizontal gene transfer (HGT) in enterococci.
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Affiliation(s)
- M Conwell
- The Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA
| | - Jsg Dooley
- The Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA
| | - P J Naughton
- The Nutrition Innovation Centre for Food and Health (NICHE), School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, Co. Londonderry, BT52 1SA
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8
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Kang J, Zhou X, Zhang W, Pei F, Ge J. Transcriptomic analysis of bacteriocin synthesis and stress response in Lactobacillus paracasei HD1.7 under acetic acid stress. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2021.112897] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Shlla B, Gazioglu O, Shafeeq S, Manzoor I, Kuipers OP, Ulijasz A, Hiller NL, Andrew PW, Yesilkaya H. The Rgg1518 transcriptional regulator is a necessary facet of sugar metabolism and virulence in Streptococcus pneumoniae. Mol Microbiol 2021; 116:996-1008. [PMID: 34328238 DOI: 10.1111/mmi.14788] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 10/20/2022]
Abstract
Rggs are a group of transcriptional regulators with diverse roles in metabolism and virulence. Here, we present work on the Rgg1518/SHP1518 quorum sensing system of Streptococcus pneumoniae. The activity of Rgg1518 is induced by its cognate peptide, SHP1518. In vitro analysis showed that the Rgg1518 system is active in conditions rich in galactose and mannose, key nutrients during nasopharyngeal colonization. Rgg1518 expression is highly induced in the presence of these sugars and its isogenic mutant is attenuated in growth on galactose and mannose. When compared with other Rgg systems, Rgg1518 has the largest regulon on galactose. On galactose it controls up- or downregulation of a functionally diverse set of genes involved in galactose metabolism, capsule biosynthesis, iron metabolism, protein translation, as well as other metabolic functions, acting mainly as a repressor of gene expression. Rgg1518 is a repressor of capsule biosynthesis, and binds directly to the capsule regulatory region. Comparison with other Rggs revealed inter-regulatory interactions among Rggs. Finally, the rgg1518 mutant is attenuated in colonization and virulence in a mouse model of colonization and pneumonia. We conclude that Rgg1518 is a virulence determinant that contributes to a regulatory network composed of multiple Rgg systems.
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Affiliation(s)
- Bushra Shlla
- Department of Respiratory Sciences, University of Leicester, Leicester, UK.,Department of Biology, College of Science, University of Mosul, Mosul, Iraq
| | - Ozcan Gazioglu
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Sulman Shafeeq
- Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Irfan Manzoor
- Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Oscar P Kuipers
- Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Andrew Ulijasz
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, USA
| | - N Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Peter W Andrew
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Hasan Yesilkaya
- Department of Respiratory Sciences, University of Leicester, Leicester, UK
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Kranjec C, Kristensen SS, Bartkiewicz KT, Brønner M, Cavanagh JP, Srikantam A, Mathiesen G, Diep DB. A bacteriocin-based treatment option for Staphylococcus haemolyticus biofilms. Sci Rep 2021; 11:13909. [PMID: 34230527 PMCID: PMC8260761 DOI: 10.1038/s41598-021-93158-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 06/15/2021] [Indexed: 01/19/2023] Open
Abstract
Bacteriocins are ribosomally-synthesized antimicrobial peptides, showing great potential as novel treatment options for multidrug-resistant pathogens. In this study, we designed a novel hybrid bacteriocin, Hybrid 1 (H1), by combing the N-terminal part and the C-terminal part of the related bacteriocins enterocin K1 (K1) and enterocin EJ97 (EJ97), respectively. Like the parental bacteriocins, H1 used the membrane-bound protease RseP as receptor, however, it differed from the others in the inhibition spectrum. Most notably, H1 showed a superior antimicrobial effect towards Staphylococcus haemolyticus—an important nosocomial pathogen. To avoid strain-dependency, we further evaluated H1 against 27 clinical and commensal S. haemolyticus strains, with H1 indeed showing high activity towards all strains. To curtail the rise of resistant mutants and further explore the potential of H1 as a therapeutic agent, we designed a bacteriocin-based formulation where H1 was used in combination with the broad-spectrum bacteriocins micrococcin P1 and garvicin KS. Unlike the individual bacteriocins, the three-component combination was highly effective against planktonic cells and completely eradicated biofilm-associated S. haemolyticus cells in vitro. Most importantly, the formulation efficiently prevented development of resistant mutants as well. These findings indicate the potential of a bacteriocins-based formulation as a treatment option for S. haemolyticus.
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Affiliation(s)
- Christian Kranjec
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Sofie S Kristensen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Karolina T Bartkiewicz
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Mikkel Brønner
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Jorunn P Cavanagh
- Pediatric Infections Group, Department of Pediatrics, University Hospital of North Norway, Tromsö, Norway.,Pediatric Infections Group, Department of Clinical Medicine, UiT the Arctic University of Norway, Tromsö, Norway
| | - Aparna Srikantam
- Blue Peter Public Health and Research Centre, LEPRA Society, Hyderabad, India
| | - Geir Mathiesen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Dzung B Diep
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
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Abstract
Gram-positive bacteria employ an array of secreted peptides to control population-level behaviors in response to environmental cues. We review mechanistic and functional features of secreted peptides produced by the human pathogen Streptococcus pneumoniae. We discuss sequence features, mechanisms of transport, and receptors for 3 major categories of small peptides: the double-glycine peptides, the Rap, Rgg, NprR, PlcR, and PrgX (RRNPP)-binding peptides, and the lanthionine-containing peptides. We highlight the impact of factors that contribute to carriage and pathogenesis, specifically genetic diversity, microbial competition, biofilm development, and environmental adaptation. A recent expansion in pneumococcal peptide studies reveals a complex network of interacting signaling systems where multiple peptides are integrated into the same signaling pathway, allowing multiple points of entry into the pathway and extending information content in new directions. In addition, since peptides are present in the extracellular milieu, there are opportunities for crosstalk, quorum sensing (QS), as well as intra- and interstrain and species interactions. Knowledge on the manner that population-level behaviors contribute to disease provides an avenue for the design and development of anti-infective strategies.
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Lingeswaran A, Metton C, Henry C, Monnet V, Juillard V, Gardan R. Export of Rgg Quorum Sensing Peptides is Mediated by the PptAB ABC Transporter in Streptococcus Thermophilus Strain LMD-9. Genes (Basel) 2020; 11:genes11091096. [PMID: 32961685 PMCID: PMC7564271 DOI: 10.3390/genes11091096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/10/2020] [Accepted: 09/17/2020] [Indexed: 12/26/2022] Open
Abstract
In streptococci, intracellular quorum sensing pathways are based on quorum-sensing systems that are responsible for peptide secretion, maturation, and reimport. These peptides then interact with Rgg or ComR transcriptional regulators in the Rap, Rgg, NprR, PlcR, and PrgX (RRNPP) family, whose members are found in Gram-positive bacteria. Short hydrophobic peptides (SHP) interact with Rgg whereas ComS peptides interact with ComR regulators. To date, in Streptococcus thermophilus, peptide secretion, maturation, and extracellular fate have received little attention, even though this species has several (at least five) genes encoding Rgg regulators and one encoding a ComR regulator. We studied pheromone export in this species, focusing our attention on PptAB, which is an exporter of signaling peptides previously identified in Enterococcus faecalis, pathogenic streptococci and Staphylococcus aureus. In the S. thermophilus strain LMD-9, we showed that PptAB controlled three regulation systems, two SHP/Rgg systems (SHP/Rgg1358 and SHP/Rgg1299), and the ComS/ComR system, while using transcriptional fusions and that PptAB helped to produce and export at least three different mature SHPs (SHP1358, SHP1299, and SHP279) peptides while using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Using a deep sequencing approach (RNAseq), we showed that the exporter PptAB, the membrane protease Eep, and the oligopeptide importer Ami controlled the transcription of the genes that were located downstream from the five non-truncated rgg genes as well as few distal genes. This led us to propose that the five non-truncated shp/rgg loci were functional. Only three shp genes were expressed in our experimental condition. Thus, this transcriptome analysis also highlighted the complex interconnected network that exists between SHP/Rgg systems, where a few homologous signaling peptides likely interact with different regulators.
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Involvement of Chromosomally Encoded Homologs of the RRNPP Protein Family in Enterococcus faecalis Biofilm Formation and Urinary Tract Infection Pathogenesis. J Bacteriol 2020; 202:JB.00063-20. [PMID: 32540933 DOI: 10.1128/jb.00063-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/02/2020] [Indexed: 11/20/2022] Open
Abstract
Enterococcus faecalis is an opportunistic pathogen capable of causing infections, including endocarditis and urinary tract infections (UTI). One of the well-characterized quorum-sensing pathways in E. faecalis involves coordination of the conjugal transfer of pheromone-responsive plasmids by PrgX, a member of the RRNPP protein family. Members of this protein family in various Firmicutes have also been shown to contribute to numerous cellular processes, including sporulation, competence, conjugation, nutrient sensing, biofilm formation, and virulence. As PrgX is a plasmid-encoded RRNPP family member, we surveyed the genome of the multidrug-resistant strain V583 for additional RRNPP homologs using computational searches and refined those identified hits for predicted structural similarities to known RRNPP family members. This led us to investigate the contribution of the chromosomally encoded RRNPP homologs to biofilm processes and pathogenesis in a catheter-associated urinary tract infection (CAUTI) model. In this study, we identified five such homologs and report that 3 of the 5 homologs, EF0073, EF1599, and EF1316, affect biofilm formation as well as outcomes in the CAUTI model.IMPORTANCE Enterococcus faecalis causes health care-associated infections and displays resistance to a variety of broad-spectrum antibiotics by acquisition of resistance traits as well as the ability to form biofilms. Even though a growing number of factors related to biofilm formation have been identified, mechanisms that contribute to biofilm formation are still largely unknown. Members of the RRNPP protein family regulate a diverse set of biological reactions in low-G+C Gram-positive bacteria (Firmicutes). Here, we identify three predicted structural homologs of the RRNPP family, EF0073, EF1599, and EF1316, which affect biofilm formation and CAUTI pathogenesis.
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Abstract
Staphylococcus aureus can colonize the human host and cause a variety of superficial and invasive infections. The success of S. aureus as a pathogen derives from its ability to modulate its virulence through the release, sensing of and response to cyclic signaling peptides. Here we provide, for the first time, evidence that S. aureus processes and secretes small linear peptides through a specialized pathway that converts a lipoprotein leader into an extracellular peptide signal. We have identified and confirmed the machinery for each step and demonstrate that the putative membrane metalloprotease Eep and the EcsAB transporter are required to complete the processing and secretion of the peptides. In addition, we have identified several linear peptides, including the interspecies signaling molecule staph-cAM373, that are dependent on this processing and secretion pathway. These findings are particularly important because multiple Gram-positive bacteria rely on small linear peptides to control bacterial gene expression and virulence.IMPORTANCE Here, we provide evidence indicating that S. aureus secretes small linear peptides into the environment via a novel processing and secretion pathway. The discovery of a specialized pathway for the production of small linear peptides and the identification of these peptides leads to several important questions regarding their role in S. aureus biology, most interestingly, their potential to act as signaling molecules. The observations in this study provide a foundation for further in-depth studies into the biological activity of small linear peptides in S. aureus.
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Sterling AJ, Snelling WJ, Naughton PJ, Ternan NG, Dooley JSG. Competent but complex communication: The phenomena of pheromone-responsive plasmids. PLoS Pathog 2020; 16:e1008310. [PMID: 32240270 PMCID: PMC7117660 DOI: 10.1371/journal.ppat.1008310] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Enterococci are robust gram-positive bacteria that are found in a variety of surroundings and that cause a significant number of healthcare-associated infections. The genus possesses a high-efficiency pheromone-responsive plasmid (PRP) transfer system for genetic exchange that allows antimicrobial-resistance determinants to spread within bacterial populations. The pCF10 plasmid system is the best characterised, and although other PRP systems are structurally similar, they lack exact functional homologues of pCF10-encoded genes. In this review, we provide an overview of the enterococcal PRP systems, incorporating functional details for the less-well-defined systems. We catalogue the virulence-associated elements of the PRPs that have been identified to date, and we argue that this reinforces the requirement for elucidation of the less studied systems.
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Affiliation(s)
- Amy J. Sterling
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
- * E-mail:
| | - William J. Snelling
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
| | - Patrick J. Naughton
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
| | - Nigel G. Ternan
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
| | - James S. G. Dooley
- Nutrition Innovation Centre for Food and Health (NICHE), Ulster University, Coleraine, Londonderry, Northern Ireland
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16
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Gour S, Kumar V, Rana M, Yadav JK. Pheromone peptide cOB1 from native Enterococcus faecalis forms amyloid-like structures: A new paradigm for peptide pheromones. J Pept Sci 2019; 25:e3178. [PMID: 31317612 DOI: 10.1002/psc.3178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/29/2019] [Accepted: 05/04/2019] [Indexed: 12/19/2022]
Abstract
Pheromone peptides are an important component of bacterial quorum-sensing system. The pheromone peptide cOB1 (VAVLVLGA) of native commensal Enterococcus faecalis has also been identified as an antimicrobial peptide (AMP) and reported to kill the prototype clinical isolate strain of E. faecalis V583. In this study, the pheromone peptide cOB1 has shown to form amyloid-like structures, a characteristic which is never reported for a pheromone peptide so far. With in silico analysis, the peptide was predicted to be highly amyloidogenic. Further, under experimental conditions, cOB1 formed aggregates displaying characteristics of amyloid structures such as bathochromic shift in Congo red absorbance, enhancement in thioflavin T fluorescence, and fibrillar morphology under transmission electron microscopy. This novel property of pheromone peptide cOB1 may have some direct effects on the binding of the pheromone to the receptor cells and subsequent conjugative transfer, making this observation more important for the therapeutics, dealing with the generation of virulent and multidrug-resistant pathogenic strains.
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Affiliation(s)
- Shalini Gour
- Department of Biotechnology, Central University of Rajasthan, NH-8 Bandarsindri, Kishangarh Ajmer, 305817, Rajasthan, India
| | - Vijay Kumar
- Department of Biotechnology, Central University of Rajasthan, NH-8 Bandarsindri, Kishangarh Ajmer, 305817, Rajasthan, India
| | - Monika Rana
- Department of Chemistry, Central University of Rajasthan, NH-8, Bandarsindri, Kishangarh Ajmer, 305817, Rajasthan, India
| | - Jay Kant Yadav
- Department of Biotechnology, Central University of Rajasthan, NH-8 Bandarsindri, Kishangarh Ajmer, 305817, Rajasthan, India
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17
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Vickerman MM, Mansfield JM. Streptococcal peptides that signal Enterococcus faecalis cells carrying the pheromone-responsive conjugative plasmid pAM373. Mol Oral Microbiol 2019; 34:254-262. [PMID: 31610092 DOI: 10.1111/omi.12271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/11/2019] [Accepted: 10/09/2019] [Indexed: 01/30/2023]
Abstract
Pheromone-mediated conjugative transfer of enterococcal plasmids can contribute to the dissemination of genes involved in antibiotic resistance, fitness, and virulence among co-residents of mixed microbial communities. We have previously shown that intergeneric signaling by the Streptococcus gordonii strain Challis heptapeptide s.g.cAM373 (SVFILAA) induces an aggregation substance-mediated mating response and facilitates plasmid transfer from Enterococcus faecalis cells carrying the pheromone-responsive plasmid pAM373 to both pheromone-producing and non-pheromone-producing oral streptococcal recipients. To further investigate the streptococcal pheromone-like peptides, s.g.cAM373-like sequences were identified in the signal sequences of streptococcal CamG lipoproteins and their abilities to induce a mating response in E. faecalis/pAM373 cells were examined. Synthetic heptamers with the consensus sequence (A/S)-(I/V)-F-I-L-(A/V/T)-(S/A) induced AS-mediated clumping. The conserved pheromone ABC transporter encoded by S. gordonii genome loci SGO_RS02660 and SGO_RS02665 was identified and confirmed to be required for s.g.cAM373 activity. Functional assays of culture supernatants from representative oral and blood isolates of S. gordonii showed that in addition to strains encoding s.g.cAM373, strain SK120, encoding the newly identified pheromone s.g.cAM373-V (SVFILVA), was able to induce enterococcal clumping, whereas strains SK6, SK8, SK9, and SK86 which encoded s.g.cAM373-T (SVFILTA) did not elicit a detectable mating response. Absence of pheromone activity in supernatants of heterologous hosts encoding its CamG precursor suggested that s.g.cAM373-T was not effectively processed and/or transported. Overall, these studies demonstrated the distribution of active pheromone peptides among strains of S. gordonii, and support a potential role for enterococcal-streptococcal communication in contributing to genetic plasticity in the oral metagenome.
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Affiliation(s)
- M Margaret Vickerman
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, USA
| | - Jillian M Mansfield
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, USA
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18
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Suryaletha K, Narendrakumar L, John J, Radhakrishnan MP, George S, Thomas S. Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants. BMC Microbiol 2019; 19:146. [PMID: 31253082 PMCID: PMC6599329 DOI: 10.1186/s12866-019-1527-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/20/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Enterococcus faecalis is a major clinically relevant nosocomial bacterial pathogen frequently isolated from polymicrobial infections. The biofilm forming ability of E. faecalis attributes a key role in its virulence and drug resistance. Biofilm cells are phenotypically and metabolically different from their planktonic counterparts and many aspects involved in E. faecalis biofilm formation are yet to be elucidated. The strain E. faecalis SK460 used in the present study is esp (Enterococcal surface protein) and fsr (two-component signal transduction system) negative non-gelatinase producing strong biofilm former isolated from a chronic diabetic foot ulcer patient. We executed a label-free quantitative proteomic approach to elucidate the differential protein expression pattern at planktonic and biofilm stages of SK460 to come up with potential determinants associated with Enterococcal biofilm formation. RESULTS The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of proteomic data revealed that biofilm cells expressed higher levels of proteins which are associated with glycolysis, amino acid biosynthesis, biosynthesis of secondary metabolites, microbial metabolism in diverse environments and stress response factors. Besides these basic survival pathways, LuxS-mediated quorum sensing, arginine metabolism, rhamnose biosynthesis, pheromone and adhesion associated proteins were found to be upregulated during the biofilm transit from planktonic stages. The selected subsets were validated by quantitative real-time PCR. In silico functional interaction analysis revealed that the genes involved in upregulated pathways pose a close molecular interaction thereby coordinating the regulatory network to thrive as a biofilm community. CONCLUSIONS The present study describes the first report of the quantitative proteome analysis of an esp and fsr negative non gelatinase producing E. faecalis. Proteome analysis evidenced enhanced expression of glycolytic pathways, stress response factors, LuxS quorum signaling system, rhamnopolysaccharide synthesis and pheromone associated proteins in biofilm phenotype. We also pointed out the relevance of LuxS quorum sensing and pheromone associated proteins in the biofilm development of E. faecalis which lacks the Fsr quorum signaling system. These validated biofilm determinants can act as potential inhibiting targets in Enterococcal infections.
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Affiliation(s)
- Karthika Suryaletha
- Cholera and Biofilm Research Laboratory, Pathogen Biology, Rajiv Gandhi Centre for Biotechnology, (National Institute under the Department of Biotechnology, Government of India), Trivandrum, Kerala, 695014, India
| | - Lekshmi Narendrakumar
- Cholera and Biofilm Research Laboratory, Pathogen Biology, Rajiv Gandhi Centre for Biotechnology, (National Institute under the Department of Biotechnology, Government of India), Trivandrum, Kerala, 695014, India
| | - Joby John
- Department of Surgery, Government Medical College Hospital, Trivandrum, Kerala, 695011, India
| | - Megha Periyappilly Radhakrishnan
- Cholera and Biofilm Research Laboratory, Pathogen Biology, Rajiv Gandhi Centre for Biotechnology, (National Institute under the Department of Biotechnology, Government of India), Trivandrum, Kerala, 695014, India
| | - Sanil George
- Interdisciplinary Biology, Rajiv Gandhi Centre for Biotechnology, Trivandrum, Kerala, 695014, India
| | - Sabu Thomas
- Cholera and Biofilm Research Laboratory, Pathogen Biology, Rajiv Gandhi Centre for Biotechnology, (National Institute under the Department of Biotechnology, Government of India), Trivandrum, Kerala, 695014, India.
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Lees JA, Ferwerda B, Kremer PHC, Wheeler NE, Serón MV, Croucher NJ, Gladstone RA, Bootsma HJ, Rots NY, Wijmega-Monsuur AJ, Sanders EAM, Trzciński K, Wyllie AL, Zwinderman AH, van den Berg LH, van Rheenen W, Veldink JH, Harboe ZB, Lundbo LF, de Groot LCPGM, van Schoor NM, van der Velde N, Ängquist LH, Sørensen TIA, Nohr EA, Mentzer AJ, Mills TC, Knight JC, du Plessis M, Nzenze S, Weiser JN, Parkhill J, Madhi S, Benfield T, von Gottberg A, van der Ende A, Brouwer MC, Barrett JC, Bentley SD, van de Beek D. Joint sequencing of human and pathogen genomes reveals the genetics of pneumococcal meningitis. Nat Commun 2019; 10:2176. [PMID: 31092817 PMCID: PMC6520353 DOI: 10.1038/s41467-019-09976-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 04/11/2019] [Indexed: 12/21/2022] Open
Abstract
Streptococcus pneumoniae is a common nasopharyngeal colonizer, but can also cause life-threatening invasive diseases such as empyema, bacteremia and meningitis. Genetic variation of host and pathogen is known to play a role in invasive pneumococcal disease, though to what extent is unknown. In a genome-wide association study of human and pathogen we show that human variation explains almost half of variation in susceptibility to pneumococcal meningitis and one-third of variation in severity, identifying variants in CCDC33 associated with susceptibility. Pneumococcal genetic variation explains a large amount of invasive potential (70%), but has no effect on severity. Serotype alone is insufficient to explain invasiveness, suggesting other pneumococcal factors are involved in progression to invasive disease. We identify pneumococcal genes involved in invasiveness including pspC and zmpD, and perform a human-bacteria interaction analysis. These genes are potential candidates for the development of more broadly-acting pneumococcal vaccines.
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Affiliation(s)
- John A Lees
- Department of Microbiology, New York University School of Medicine, New York, NY, 10016, USA
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, CB10 1SA, UK
| | - Bart Ferwerda
- Amsterdam UMC, University of Amsterdam, Department of Neurology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
| | - Philip H C Kremer
- Amsterdam UMC, University of Amsterdam, Department of Neurology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
| | - Nicole E Wheeler
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, CB10 1SA, UK
- The Centre for Genomic Pathogen Surveillance, Wellcome Sanger Institute, Cambridge, CB10 1SA, UK
| | - Mercedes Valls Serón
- Amsterdam UMC, University of Amsterdam, Department of Neurology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
| | - Nicholas J Croucher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK
| | | | - Hester J Bootsma
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, 3721 MA, The Netherlands
| | - Nynke Y Rots
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, 3721 MA, The Netherlands
| | - Alienke J Wijmega-Monsuur
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, 3721 MA, The Netherlands
| | - Elisabeth A M Sanders
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, 3721 MA, The Netherlands
- Department of Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, 3508 AB, The Netherlands
| | - Krzysztof Trzciński
- Department of Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, 3508 AB, The Netherlands
| | - Anne L Wyllie
- Department of Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, 3508 AB, The Netherlands
- Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06520, USA
| | - Aeilko H Zwinderman
- Amsterdam UMC, University of Amsterdam, Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam Public Health, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
| | - Leonard H van den Berg
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, 3584 CG, The Netherlands
| | - Wouter van Rheenen
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, 3584 CG, The Netherlands
| | - Jan H Veldink
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, 3584 CG, The Netherlands
| | - Zitta B Harboe
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, DK-2300, Denmark
| | - Lene F Lundbo
- Department of Infectious Diseases, Hvidovre Hospital, University of Copenhagen, Hvidovre, 2650, Denmark
| | - Lisette C P G M de Groot
- Department of Human Nutrition, Wageningen University, P.O. Box 17, 6700 AA, Wageningen, The Netherlands
| | - Natasja M van Schoor
- Amsterdam UMC, VU University, Department of Epidemiology and Biostatistics, Amsterdam Public Health, Van der Boechorststraat 7, Amsterdam, 1007 MB, The Netherlands
| | - Nathalie van der Velde
- Amsterdam UMC, University of Amsterdam, Department of Internal Medicine, Geriatrics, Amsterdam Public Health, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Lars H Ängquist
- Center for Clinical Research and Disease Prevention, Bispebjerg and Frederiksberg Hospitals, The Capital Region, Copenhagen, DK-2000, Denmark
| | - Thorkild I A Sørensen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Copenhagen, DK-2200, Denmark
- The Department of Public Health, Section of Epidemiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK-1014, Denmark
| | - Ellen A Nohr
- Institute of Clinical Research, University of Southern Denmark, Odense, DK-5000, Denmark
| | - Alexander J Mentzer
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Tara C Mills
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Julian C Knight
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Mignon du Plessis
- School of Pathology, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2000, South Africa
| | - Susan Nzenze
- School of Pathology, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2000, South Africa
| | - Jeffrey N Weiser
- Department of Microbiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Julian Parkhill
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, CB10 1SA, UK
| | - Shabir Madhi
- National Institute for Communicable Diseases, Johannesburg, 2192, South Africa
| | - Thomas Benfield
- Department of Infectious Diseases, Hvidovre Hospital, University of Copenhagen, Hvidovre, 2650, Denmark
| | - Anne von Gottberg
- School of Pathology, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2000, South Africa
- National Institute for Communicable Diseases, Johannesburg, 2192, South Africa
| | - Arie van der Ende
- Amsterdam UMC, University of Amsterdam, Department of Medical Microbiology, Amsterdam Infection and Immunity, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
- Netherlands Reference Laboratory for Bacterial Meningitis, Amsterdam UMC/RIVM, University of Amsterdam, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
| | - Matthijs C Brouwer
- Amsterdam UMC, University of Amsterdam, Department of Neurology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
| | - Jeffrey C Barrett
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, CB10 1SA, UK
- Genomics Plc, East Road, Cambridge, CB1 1BH, UK
| | - Stephen D Bentley
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, CB10 1SA, UK.
| | - Diederik van de Beek
- Amsterdam UMC, University of Amsterdam, Department of Neurology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands.
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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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Verbeke F, Debunne N, Janssens Y, Tack L, Wynendaele E, Rigole P, Coenye T, De Spiegeleer B. Detection and quantification of Enterococcus faecalis RNPP-type quorum sensing peptides in bacterial culture media by UHPLC-MS. J Pharm Biomed Anal 2018; 160:55-63. [DOI: 10.1016/j.jpba.2018.07.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 07/08/2018] [Accepted: 07/14/2018] [Indexed: 11/29/2022]
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22
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Pham HT, Nhiep NTH, Vu TNM, Huynh TN, Zhu Y, Huynh ALD, Chakrabortti A, Marcellin E, Lo R, Howard CB, Bansal N, Woodward JJ, Liang ZX, Turner MS. Enhanced uptake of potassium or glycine betaine or export of cyclic-di-AMP restores osmoresistance in a high cyclic-di-AMP Lactococcus lactis mutant. PLoS Genet 2018; 14:e1007574. [PMID: 30074984 PMCID: PMC6108528 DOI: 10.1371/journal.pgen.1007574] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/24/2018] [Accepted: 07/20/2018] [Indexed: 11/22/2022] Open
Abstract
The broadly conserved bacterial signalling molecule cyclic-di-adenosine monophosphate (c-di-AMP) controls osmoresistance via its regulation of potassium (K+) and compatible solute uptake. High levels of c-di-AMP resulting from inactivation of c-di-AMP phosphodiesterase activity leads to poor growth of bacteria under high osmotic conditions. To better understand how bacteria can adjust in response to excessive c-di-AMP levels and to identify signals that feed into the c-di-AMP network, we characterised genes identified in a screen for osmoresistant suppressor mutants of the high c-di-AMP Lactococcus ΔgdpP strain. Mutations were identified which increased the uptake of osmoprotectants, including gain-of-function mutations in a Kup family K+ importer (KupB) and inactivation of the glycine betaine transporter transcriptional repressor BusR. The KupB mutations increased the intracellular K+ level while BusR inactivation increased the glycine betaine level. In addition, BusR was found to directly bind c-di-AMP and repress expression of the glycine betaine transporter in response to elevated c-di-AMP. Interestingly, overactive KupB activity or loss of BusR triggered c-di-AMP accumulation, suggesting turgor pressure changes act as a signal for this second messenger. In another group of suppressors, overexpression of an operon encoding an EmrB family multidrug resistance protein allowed cells to lower their intracellular level of c-di-AMP through active export. Lastly evidence is provided that c-di-AMP levels in several bacteria are rapidly responsive to environmental osmolarity changes. Taken together, this work provides evidence for a model in which high c-di-AMP containing cells are dehydrated due to lower K+ and compatible solute levels and that this osmoregulation system is able to sense and respond to cellular water stress.
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Affiliation(s)
- Huong Thi Pham
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
- The University of Danang, University of Science and Technology, Da Nang, Vietnam
| | - Nguyen Thi Hanh Nhiep
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Thu Ngoc Minh Vu
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - TuAnh Ngoc Huynh
- Department of Microbiology, University of Washington, Seattle, WA, United States of America
| | - Yan Zhu
- Monash Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Anh Le Diep Huynh
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | | | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Queensland, Australia
| | - Raquel Lo
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Christopher B. Howard
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Queensland, Australia
| | - Nidhi Bansal
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Joshua J. Woodward
- Department of Microbiology, University of Washington, Seattle, WA, United States of America
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Mark S. Turner
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, Queensland, Australia
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Yu W, Missiakas D, Schneewind O. Septal secretion of protein A in Staphylococcus aureus requires SecA and lipoteichoic acid synthesis. eLife 2018; 7:34092. [PMID: 29757141 PMCID: PMC5962339 DOI: 10.7554/elife.34092] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/05/2018] [Indexed: 12/26/2022] Open
Abstract
Surface proteins of Staphylococcus aureus are secreted across septal membranes for assembly into the bacterial cross-wall. This localized secretion requires the YSIRK/GXXS motif signal peptide, however the mechanisms supporting precursor trafficking are not known. We show here that the signal peptide of staphylococcal protein A (SpA) is cleaved at the YSIRK/GXXS motif. A SpA signal peptide mutant defective for YSIRK/GXXS cleavage is also impaired for septal secretion and co-purifies with SecA, SecDF and LtaS. SecA depletion blocks precursor targeting to septal membranes, whereas deletion of secDF diminishes SpA secretion into the cross-wall. Depletion of LtaS blocks lipoteichoic acid synthesis and abolishes SpA precursor trafficking to septal membranes. We propose a model whereby SecA directs SpA precursors to lipoteichoic acid-rich septal membranes for YSIRK/GXXS motif cleavage and secretion into the cross-wall.
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Affiliation(s)
- Wenqi Yu
- Department of Microbiology, University of Chicago, Chicago, United States
| | | | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, United States
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24
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Neiditch MB, Capodagli GC, Prehna G, Federle MJ. Genetic and Structural Analyses of RRNPP Intercellular Peptide Signaling of Gram-Positive Bacteria. Annu Rev Genet 2017; 51:311-333. [PMID: 28876981 PMCID: PMC6588834 DOI: 10.1146/annurev-genet-120116-023507] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bacteria use diffusible chemical messengers, termed pheromones, to coordinate gene expression and behavior among cells in a community by a process known as quorum sensing. Pheromones of many gram-positive bacteria, such as Bacillus and Streptococcus, are small, linear peptides secreted from cells and subsequently detected by sensory receptors such as those belonging to the large family of RRNPP proteins. These proteins are cytoplasmic pheromone receptors sharing a structurally similar pheromone-binding domain that functions allosterically to regulate receptor activity. X-ray crystal structures of prototypical RRNPP members have provided atomic-level insights into their mechanism and regulation by pheromones. This review provides an overview of RRNPP prototype signaling; describes the structure-function of this protein family, which is spread widely among gram-positive bacteria; and suggests approaches to target RRNPP systems in order to manipulate beneficial and harmful bacterial behaviors.
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Affiliation(s)
- Matthew B Neiditch
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103, USA; ,
| | - Glenn C Capodagli
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103, USA; ,
| | - Gerd Prehna
- Center for Structural Biology, Research Resources Center and Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois 60607, USA;
| | - Michael J Federle
- Department of Medicinal Chemistry and Pharmacognosy and Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, Illinois 60607, USA;
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Ovchinnikov KV, Kristiansen PE, Straume D, Jensen MS, Aleksandrzak-Piekarczyk T, Nes IF, Diep DB. The Leaderless Bacteriocin Enterocin K1 Is Highly Potent against Enterococcus faecium: A Study on Structure, Target Spectrum and Receptor. Front Microbiol 2017; 8:774. [PMID: 28515717 PMCID: PMC5413573 DOI: 10.3389/fmicb.2017.00774] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 04/18/2017] [Indexed: 12/29/2022] Open
Abstract
Enterocin K1 (EntK1), enterocin EJ97 (EntEJ97), and LsbB are three sequence related leaderless bacteriocins. Yet LsbB kills only lactococci while EntK1 and EntEJ97 target wider spectra with EntK1 being particularly active against Enterococcus faecium, including nosocomial multidrug resistant isolates. NMR study of EntK1 showed that it had a structure very similar to LsbB – both having an amphiphilic N-terminal α-helix and an unstructured C-terminus. The α-helix in EntK1 is, however, about 3–4 residues longer than that of LsbB. Enterococcal mutants highly resistant to EntEJ97 and EntK1 were found to have mutations within rseP, a gene encoding a stress response membrane-bound Zn-dependent protease. Heterologous expression of the enterococcal rseP rendered resistant cells of Streptococcus pneumoniae sensitive to EntK1 and EntEJ97, suggesting that RseP likely serves as the receptor for EntK1 and EntEJ97. It was also shown that the conserved proteolytic active site in E. faecalis RseP is partly required for EntK1 and EntEJ97 activity, since alanine substitutions of its conserved residues (HExxH) reduced the sensitivity of the clones to the bacteriocins. RseP is known to be involved in bacterial stress response. As expected, the growth of resistant mutants with mutations within rseP was severely affected when they were exposed to higher (stressing) growth temperatures, e.g., at 45°C, at which wild type cells still grew well. These findings allow us to design a hurdle strategy with a combination of the bacteriocin(s) and higher temperature that effectively kills bacteriocin sensitive bacteria and prevents the development of resistant cells.
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Affiliation(s)
- Kirill V Ovchinnikov
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life SciencesÅs, Norway
| | | | - Daniel Straume
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life SciencesÅs, Norway
| | - Marianne S Jensen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life SciencesÅs, Norway
| | | | - Ingolf F Nes
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life SciencesÅs, Norway
| | - Dzung B Diep
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life SciencesÅs, Norway
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Ali L, Goraya MU, Arafat Y, Ajmal M, Chen JL, Yu D. Molecular Mechanism of Quorum-Sensing in Enterococcus faecalis: Its Role in Virulence and Therapeutic Approaches. Int J Mol Sci 2017; 18:ijms18050960. [PMID: 28467378 PMCID: PMC5454873 DOI: 10.3390/ijms18050960] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 04/26/2017] [Indexed: 12/22/2022] Open
Abstract
Quorum-sensing systems control major virulence determinants in Enterococcusfaecalis, which causes nosocomial infections. The E. faecalis quorum-sensing systems include several virulence factors that are regulated by the cytolysin operon, which encodes the cytolysin toxin. In addition, the E. faecalis Fsr regulator system controls the expression of gelatinase, serine protease, and enterocin O16. The cytolysin and Fsr virulence factor systems are linked to enterococcal diseases that affect the health of humans and other host models. Therefore, there is substantial interest in understanding and targeting these regulatory pathways to develop novel therapies for enterococcal infection control. Quorum-sensing inhibitors could be potential therapeutic agents for attenuating the pathogenic effects of E. faecalis. Here, we discuss the regulation of cytolysin, the LuxS system, and the Fsr system, their role in E. faecalis-mediated infections, and possible therapeutic approaches to prevent E. faecalis infection.
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Affiliation(s)
- Liaqat Ali
- College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45550, Pakistan.
| | - Mohsan Ullah Goraya
- College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Yasir Arafat
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Muhammad Ajmal
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45550, Pakistan.
| | - Ji-Long Chen
- College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing 100101, China.
| | - Daojin Yu
- College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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Chang JC, Federle MJ. PptAB Exports Rgg Quorum-Sensing Peptides in Streptococcus. PLoS One 2016; 11:e0168461. [PMID: 27992504 PMCID: PMC5167397 DOI: 10.1371/journal.pone.0168461] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/01/2016] [Indexed: 11/30/2022] Open
Abstract
A transposon mutagenesis screen designed to identify mutants that were defective in peptide-pheromone signaling of the Rgg2/Rgg3 pathway in Streptococcus pyogenes generated insertions in sixteen loci displaying diminished reporter activity. Fourteen unique transposon insertions were mapped to pptAB, an ABC-type transporter recently described to export sex pheromones of Enterococcus faecalis. Consistent with an idea that PptAB exports signaling peptides, the pheromones known as SHPs (short hydrophobic peptides) were no longer detected in cell-free culture supernatants in a generated deletion mutant of pptAB. PptAB exporters are conserved among the Firmicutes, but their function and substrates remain unclear. Therefore, we tested a pptAB mutant generated in Streptococcus mutans and found that while secretion of heterologously expressed SHP peptides required PptAB, secretion of the S. mutans endogenous pheromone XIP (sigX inducing peptide) was only partially disrupted, indicating that a secondary secretion pathway for XIP exists.
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Affiliation(s)
- Jennifer C. Chang
- Department of Medicinal Chemistry and Pharmacognosy, Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Michael J. Federle
- Department of Medicinal Chemistry and Pharmacognosy, Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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Garai P, Chandra K, Chakravortty D. Bacterial peptide transporters: Messengers of nutrition to virulence. Virulence 2016; 8:297-309. [PMID: 27589415 DOI: 10.1080/21505594.2016.1221025] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bacteria possess numerous peptide transporters for importing peptides as nutrients. However, these peptide transporters are now consistently reported to play a role in the virulence of various bacterial pathogens. Their ability to transport peptides has implications in antibacterial therapy as well. Therefore, it would be instrumental to have complete knowledge about the role of peptide transporters in mediating this cross connection between metabolism and pathogenesis. Studies on various peptide transporters in bacterial pathogens have improved our understanding of this field. In this review, we have given an overview of the functioning of bacterial peptide transporters and their contribution in virulence of major bacterial pathogens.
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Affiliation(s)
- Preeti Garai
- a Department of Microbiology and Cell Biology , Indian Institute of Science , Bangalore , India
| | - Kasturi Chandra
- a Department of Microbiology and Cell Biology , Indian Institute of Science , Bangalore , India
| | - Dipshikha Chakravortty
- a Department of Microbiology and Cell Biology , Indian Institute of Science , Bangalore , India
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Comparative transcriptome analysis of fruiting body and sporulating mycelia of Villosiclava virens reveals genes with putative functions in sexual reproduction. Curr Genet 2016; 62:575-84. [DOI: 10.1007/s00294-015-0563-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 12/23/2015] [Accepted: 12/30/2015] [Indexed: 10/22/2022]
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Pheromone killing of multidrug-resistant Enterococcus faecalis V583 by native commensal strains. Proc Natl Acad Sci U S A 2015; 112:7273-8. [PMID: 26039987 PMCID: PMC4466700 DOI: 10.1073/pnas.1500553112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Multidrug-resistant enterococci are leading causes of hospital infection. The antibiotic-perturbed patient gut serves as a staging ground—small numbers of resistant hospital strains colonize and then, greatly amplify in the colon. Little is known of the colonization principles involved—whether hospital strains are competitive or noncompetitive with commensal enterococci or whether mobile elements comprising over 25% of the genome of the former impose significant fitness costs. We unexpectedly found that the prototype vancomycin-resistant Enterococcus faecalis strain V583 was actively killed by fecal organisms, and we traced that to pheromone production by commensal enterococci that trigger lethal mobile element cross-talk. This work highlights the importance of maintaining commensal enterococci in the gut of the hospitalized patient. Multidrug-resistant Enterococcus faecalis possess numerous mobile elements that encode virulence and antibiotic resistance traits as well as new metabolic pathways, often constituting over one-quarter of the genome. It was of interest to determine how this large accretion of mobile elements affects competitive growth in the gastrointestinal (GI) tract consortium. We unexpectedly observed that the prototype clinical isolate strain V583 was actively killed by GI tract flora, whereas commensal enterococci flourished. It was found that killing of V583 resulted from lethal cross-talk between accumulated mobile elements and that this cross-talk was induced by a heptapeptide pheromone produced by native E. faecalis present in the fecal consortium. These results highlight two important aspects of the evolution of multidrug-resistant enterococci: (i) the accretion of mobile elements in E. faecalis V583 renders it incompatible with commensal strains, and (ii) because of this incompatibility, multidrug-resistant strains sharing features found in V583 cannot coexist with commensal strains. The accumulation of mobile elements in hospital isolates of enterococci can include those that are inherently incompatible with native flora, highlighting the importance of maintaining commensal populations as means of preventing colonization and subsequent infection by multidrug-resistant strains.
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RovS and its associated signaling peptide form a cell-to-cell communication system required for Streptococcus agalactiae pathogenesis. mBio 2015; 6:mBio.02306-14. [PMID: 25604789 PMCID: PMC4324310 DOI: 10.1128/mbio.02306-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Bacteria can communicate with each other to coordinate their biological functions at the population level. In a previous study, we described a cell-to-cell communication system in streptococci that involves a transcriptional regulator belonging to the Rgg family and short hydrophobic peptides (SHPs) that act as signaling molecules. Streptococcus agalactiae, an opportunistic pathogenic bacterium responsible for fatal infections in neonates and immunocompromised adults, has one copy of the shp/rgg locus. The SHP-associated Rgg is called RovS in S. agalactiae. In this study, we found that the SHP/RovS cell-to-cell communication system is active in the strain NEM316 of S. agalactiae, and we identified different partners that are involved in this system, such as the Eep peptidase, the PptAB, and the OppA1-F oligopeptide transporters. We also identified a new target gene controlled by this system and reexamined the regulation of a previously proposed target gene, fbsA, in the context of the SHP-associated RovS system. Furthermore, our results are the first to indicate the SHP/RovS system specificity to host liver and spleen using a murine model, which demonstrates its implication in streptococci virulence. Finally, we observed that SHP/RovS regulation influences S. agalactiae's ability to adhere to and invade HepG2 hepatic cells. Hence, the SHP/RovS cell-to-cell communication system appears to be an essential mechanism that regulates pathogenicity in S. agalactiae and represents an attractive target for the development of new therapeutic strategies. IMPORTANCE Rgg regulators and their cognate pheromones, called small hydrophobic peptides (SHPs), are present in nearly all streptococcal species. The general pathways of the cell-to-cell communication system in which Rgg and SHP take part are well understood. However, many other players remain unidentified, and the direct targets of the system, as well as its link to virulence, remain unclear. Here, we identified the different players involved in the SHP/Rgg system in S. agalactiae, which is the leading agent of severe infections in human newborns. We have identified a direct target of the Rgg regulator in S. agalactiae (called RovS) and examined a previously proposed target, all in the context of associated SHP. For the first time, we have also demonstrated the implication of the SHP/RovS mechanism in virulence, as well as its host organ specificity. Thus, this cell-to-cell communication system may represent a future target for S. agalactiae disease treatment.
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