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Canè C, Gallucci N, Amoresano A, Fontanarosa C, Paduano L, De Gregorio E, Duilio A, Di Somma A. The antimicrobial peptide Temporin-L induces vesicle formation and reduces the virulence in S. aureus. Biochem Biophys Rep 2024; 39:101808. [PMID: 39238505 PMCID: PMC11375239 DOI: 10.1016/j.bbrep.2024.101808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 06/06/2024] [Accepted: 08/04/2024] [Indexed: 09/07/2024] Open
Abstract
The evolution of methicillin-resistant Staphylococcus aureus (MRSA) has required the development of new antimicrobial agents and new approaches to prevent and overcome drug resistance. AntiMicrobial Peptides (AMPs) represent promising alternatives due to their rapid bactericidal activity and their broad-spectrum of action against a wide range of microorganisms. The amphibian Temporins constitute a well-known family of AMPs with high antibacterial properties against both Gram-positive and Gram-negative bacteria. In this paper, we evaluated the in vivo effect of Temp-L on S. aureus performing morphological studies using Transmission Electron Microscopy (TEM) that revealed the occurrence of protrusions from the cell surface. The formation of vesicle-like structure was confirmed by Dynamic Light Scattering (DLS). The global effect of Temp-L on Staphylococcus aureus (S. aureus) was deeply investigated by differential proteomics leading to the identification of up-regulated proteins involved in the synthesis of the cell membrane and fatty acids, and down-regulated virulence factors. GC-MS analysis suggested a possible protective response mechanism implemented by the bacterium after treatment with Temp-L, as the synthesis of fatty acids was increased. Adhesion and invasion assays on eukaryotic cells confirmed a reduced virulence of S. aureus following treatment with Temp-L. These results suggested the targeting of virulence factors as novel strategy to replace traditional antimicrobial agents that can be used to treat infections, especially infections caused by the resistant pathogen S. aureus.
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Affiliation(s)
- Carolina Canè
- Department of Chemical Sciences, University of Naples "Federico II" Via Cinthia 4, 80126, Napoli, Italy
| | - Noemi Gallucci
- Department of Chemical Sciences, University of Naples "Federico II" Via Cinthia 4, 80126, Napoli, Italy
| | - Angela Amoresano
- Department of Chemical Sciences, University of Naples "Federico II" Via Cinthia 4, 80126, Napoli, Italy
- National Institute of Biostructures and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136, Rome, Italy
| | - Carolina Fontanarosa
- Department of Chemical Sciences, University of Naples "Federico II" Via Cinthia 4, 80126, Napoli, Italy
| | - Luigi Paduano
- Department of Chemical Sciences, University of Naples "Federico II" Via Cinthia 4, 80126, Napoli, Italy
| | - Eliana De Gregorio
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via S. Pansini 5, 80131, Naples, Italy
| | - Angela Duilio
- Department of Chemical Sciences, University of Naples "Federico II" Via Cinthia 4, 80126, Napoli, Italy
- National Institute of Biostructures and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136, Rome, Italy
| | - Angela Di Somma
- Department of Chemical Sciences, University of Naples "Federico II" Via Cinthia 4, 80126, Napoli, Italy
- CEINGE Biotecnologie Avanzate, Via Gaetano Salvatore 486, 80126, Napoli, Italy
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2
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Akbari MS, Joyce LR, Spencer BL, McIver KS, Doran KS. Identification of Glyoxalase A in Group B Streptococcus and its contribution to methylglyoxal tolerance and virulence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.30.605887. [PMID: 39131367 PMCID: PMC11312555 DOI: 10.1101/2024.07.30.605887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Group B Streptococcus (GBS) is a Gram-positive pathobiont that commonly colonizes the gastrointestinal and lower female genital tracts but can cause sepsis and pneumonia in newborns and is a leading cause of neonatal meningitis. Despite the resulting disease severity, the pathogenesis of GBS is not completely understood, especially during the early phases of infection. To investigate GBS factors necessary for blood stream survival, we performed a transposon (Tn) mutant screen in our bacteremia infection model using a GBS mariner transposon mutant library previously developed by our group. We identified significantly underrepresented mutations in 628 genes that contribute to survival in the blood, including those encoding known virulence factors such as capsule, the β-hemolysin, and inorganic metal ion transport systems. Most of the underrepresented genes have not been previously characterized or studied in GBS, including gloA and gloB, which are homologs for genes involved in methylglyoxal (MG) detoxification. MG is a byproduct of glycolysis and a highly reactive toxic aldehyde that is elevated in immune cells during infection. Here, we observed MG sensitivity across multiple GBS isolates and confirm that gloA contributes to MG tolerance and invasive GBS infection. We show specifically that gloA contributes to GBS survival in the presence of neutrophils and depleting neutrophils in mice abrogates the decreased survival and infection of the gloA mutant. The requirement of the glyoxalase pathway during GBS infection suggests that MG detoxification is important for bacterial survival during host-pathogen interactions.
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Affiliation(s)
- Madeline S. Akbari
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado USA
| | - Luke R. Joyce
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado USA
| | - Brady L. Spencer
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado USA
| | - Kevin S. McIver
- Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Kelly S. Doran
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado USA
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3
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Joyce LR, Kim S, Spencer BL, Christensen PM, Palmer KL, Guan Z, Siegenthaler JA, Doran KS. Streptococcus agalactiae glycolipids promote virulence by thwarting immune cell clearance. SCIENCE ADVANCES 2024; 10:eadn7848. [PMID: 38809989 PMCID: PMC11135403 DOI: 10.1126/sciadv.adn7848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 04/25/2024] [Indexed: 05/31/2024]
Abstract
Streptococcus agalactiae [group B Streptococcus (GBS)] is a leading cause of neonatal meningitis, with late-onset disease (LOD) occurring after gastrointestinal tract colonization in infants. Bacterial membrane lipids are essential for host-pathogen interactions, and the functions of glycolipids are yet to be fully elucidated. GBS synthesizes three major glycolipids: glucosyl-diacylglycerol (Glc-DAG), diglucosyl-DAG (Glc2-DAG), and lysyl-Glc-DAG (Lys-Glc-DAG). Here, we identify the enzyme, IagB, as responsible for biosynthesis of Glc-DAG, the precursor for the two other glycolipids in GBS. To examine the collective role of glycolipids to GBS virulence, we adapted a murine model of neonatal meningitis to simulate LOD. The GBS∆iagB mutant traversed the gut-epithelial barrier comparable to wild type but was severely attenuated in bloodstream survival, resulting in decreased bacterial loads in the brain. The GBS∆iagB mutant was more susceptible to neutrophil killing and membrane targeting by host antimicrobial peptides. This work reveals an unexplored function of GBS glycolipids with their ability to protect the bacterial cell from host antimicrobial killing.
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Affiliation(s)
- Luke R. Joyce
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Sol Kim
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Brady L. Spencer
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Priya M. Christensen
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Kelli L. Palmer
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Julie A. Siegenthaler
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Kelly S. Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
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4
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Lê-Bury P, Echenique-Rivera H, Pizarro-Cerdá J, Dussurget O. Determinants of bacterial survival and proliferation in blood. FEMS Microbiol Rev 2024; 48:fuae013. [PMID: 38734892 PMCID: PMC11163986 DOI: 10.1093/femsre/fuae013] [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: 11/06/2023] [Revised: 04/29/2024] [Accepted: 05/10/2024] [Indexed: 05/13/2024] Open
Abstract
Bloodstream infection is a major public health concern associated with high mortality and high healthcare costs worldwide. Bacteremia can trigger fatal sepsis whose prevention, diagnosis, and management have been recognized as a global health priority by the World Health Organization. Additionally, infection control is increasingly threatened by antimicrobial resistance, which is the focus of global action plans in the framework of a One Health response. In-depth knowledge of the infection process is needed to develop efficient preventive and therapeutic measures. The pathogenesis of bloodstream infection is a dynamic process resulting from the invasion of the vascular system by bacteria, which finely regulate their metabolic pathways and virulence factors to overcome the blood immune defenses and proliferate. In this review, we highlight our current understanding of determinants of bacterial survival and proliferation in the bloodstream and discuss their interactions with the molecular and cellular components of blood.
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Affiliation(s)
- Pierre Lê-Bury
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Autoimmune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT), 18 route du Panorama, 92260 Fontenay-aux-Roses, France
| | - Hebert Echenique-Rivera
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
| | - Javier Pizarro-Cerdá
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Institut Pasteur, Université Paris Cité, Yersinia National Reference Laboratory, WHO Collaborating Research & Reference Centre for Plague FRA-146, 28 rue du Dr Roux, 75015 Paris, France
| | - Olivier Dussurget
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
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5
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Zhang P, Liu Z. Structural insights into the transporting and catalyzing mechanism of DltB in LTA D-alanylation. Nat Commun 2024; 15:3404. [PMID: 38649359 PMCID: PMC11035591 DOI: 10.1038/s41467-024-47783-7] [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: 06/21/2023] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
DltB, a model member of the Membrane-Bound O-AcylTransferase (MBOAT) superfamily, plays a crucial role in D-alanylation of the lipoteichoic acid (LTA), a significant component of the cell wall of gram-positive bacteria. This process stabilizes the cell wall structure, influences bacterial virulence, and modulates the host immune response. Despite its significance, the role of DltB is not well understood. Through biochemical analysis and cryo-EM imaging, we discover that Streptococcus thermophilus DltB forms a homo-tetramer on the cell membrane. We further visualize DltB in an apo form, in complex with DltC, and in complex with its inhibitor amsacrine (m-AMSA). Each tetramer features a central hole. The C-tunnel of each protomer faces the intratetramer interface and provides access to the periphery membrane. Each protomer binds a DltC without changing the tetrameric organization. A phosphatidylglycerol (PG) molecule in the substrate-binding site may serve as an LTA carrier. The inhibitor m-AMSA bound to the L-tunnel of each protomer blocks the active site. The tetrameric organization of DltB provides a scaffold for catalyzing D-alanyl transfer and regulating the channel opening and closing. Our findings unveil DltB's dual function in the D-alanylation pathway, and provide insight for targeting DltB as a anti-virulence antibiotic.
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Affiliation(s)
- Pingfeng Zhang
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China.
| | - Zheng Liu
- Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Shenzhen, China.
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6
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Schultz BJ, Snow ED, Walker S. Mechanism of D-alanine transfer to teichoic acids shows how bacteria acylate cell envelope polymers. Nat Microbiol 2023; 8:1318-1329. [PMID: 37308592 PMCID: PMC10664464 DOI: 10.1038/s41564-023-01411-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/17/2023] [Indexed: 06/14/2023]
Abstract
Bacterial cell envelope polymers are often modified with acyl esters that modulate physiology, enhance pathogenesis and provide antibiotic resistance. Here, using the D-alanylation of lipoteichoic acid (Dlt) pathway as a paradigm, we have identified a widespread strategy for how acylation of cell envelope polymers occurs. In this strategy, a membrane-bound O-acyltransferase (MBOAT) protein transfers an acyl group from an intracellular thioester onto the tyrosine of an extracytoplasmic C-terminal hexapeptide motif. This motif shuttles the acyl group to a serine on a separate transferase that moves the cargo to its destination. In the Dlt pathway, here studied in Staphylococcus aureus and Streptococcus thermophilus, the C-terminal 'acyl shuttle' motif that forms the crucial pathway intermediate is found on a transmembrane microprotein that holds the MBOAT protein and the other transferase together in a complex. In other systems, found in both Gram-negative and Gram-positive bacteria as well as some archaea, the motif is fused to the MBOAT protein, which interacts directly with the other transferase. The conserved chemistry uncovered here is widely used for acylation throughout the prokaryotic world.
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Affiliation(s)
- Bailey J Schultz
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Eric D Snow
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Suzanne Walker
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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7
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Li T, Wang Z, Guo J, de la Fuente-Nunez C, Wang J, Han B, Tao H, Liu J, Wang X. Bacterial resistance to antibacterial agents: Mechanisms, control strategies, and implications for global health. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 860:160461. [PMID: 36435256 DOI: 10.1016/j.scitotenv.2022.160461] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 11/19/2022] [Accepted: 11/20/2022] [Indexed: 06/16/2023]
Abstract
The spread of bacterial drug resistance has posed a severe threat to public health globally. Here, we cover bacterial resistance to current antibacterial drugs, including traditional herbal medicines, conventional antibiotics, and antimicrobial peptides. We summarize the influence of bacterial drug resistance on global health and its economic burden while highlighting the resistance mechanisms developed by bacteria. Based on the One Health concept, we propose 4A strategies to combat bacterial resistance, including prudent Application of antibacterial agents, Administration, Assays, and Alternatives to antibiotics. Finally, we identify several opportunities and unsolved questions warranting future exploration for combating bacterial resistance, such as predicting genetic bacterial resistance through the use of more effective techniques, surveying both genetic determinants of bacterial resistance and the transmission dynamics of antibiotic resistance genes (ARGs).
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Affiliation(s)
- Ting Li
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China; State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, No. 20, Dongda Street, Fengtai District, Beijing 100071, PR China
| | - Zhenlong Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Jianhua Guo
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, St Lucia, Queensland 4072, Australia.
| | - Cesar de la Fuente-Nunez
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America; Departments of Bioengineering and Chemical and Biomolecular Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States of America; Penn Institute for Computational Science, University of Pennsylvania, Philadelphia, PA, United States of America.
| | - Jinquan Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Bing Han
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Hui Tao
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Jie Liu
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China
| | - Xiumin Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China; Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing 100081, PR China.
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8
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Öhlmann S, Krieger AK, Gisch N, Meurer M, de Buhr N, von Köckritz-Blickwede M, Schütze N, Baums CG. d-Alanylation of Lipoteichoic Acids in Streptococcus suis Reduces Association With Leukocytes in Porcine Blood. Front Microbiol 2022; 13:822369. [PMID: 35509315 PMCID: PMC9058155 DOI: 10.3389/fmicb.2022.822369] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Streptococcus suis (S. suis) is a common swine pathogen but also poses a threat to human health in causing meningitis and severe cases of streptococcal toxic shock-like syndrome (STSLS). Therefore, it is crucial to understand how S. suis interacts with the host immune system during bacteremia. As S. suis has the ability to introduce d-alanine into its lipoteichoic acids (LTAs), we investigated the working hypothesis that cell wall modification by LTA d-alanylation influences the interaction of S. suis with porcine blood immune cells. We created an isogenic mutant of S. suis strain 10 by in-frame deletion of the d-alanine d-alanyl carrier ligase (DltA). d-alanylation of LTAs was associated with reduced phagocytosis of S. suis by porcine granulocytes, reduced deposition of complement factor C3 on the bacterial surface, increased hydrophobicity of streptococci, and increased resistance to cationic antimicrobial peptides (CAMPs). At the same time, survival of S. suis was not significantly increased by LTA d-alanylation in whole blood of conventional piglets with specific IgG. However, we found a distinct cytokine pattern as IL-1β but not tumor necrosis factor (TNF)-α levels were significantly reduced in blood infected with the ΔdltA mutant. In contrast to TNF-α, activation and secretion of IL-1β are inflammasome-dependent, suggesting a possible influence of LTA d-alanylation on inflammasome regulation. Especially in the absence of specific antibodies, the association of S. suis with porcine monocytes was reduced by d-alanylation of its LTAs. This dltA-dependent phenotype was also observed with a non-encapsulated dltA double mutant indicating that it is independent of capsular polysaccharides. High antibody levels caused high levels of S. suis—monocyte—association followed by inflammatory cell death and strong production of both IL-1β and TNF-α, while the influence of LTA d-alanylation of the streptococci became less visible. In summary, the results of this study expand previous findings on d-alanylation of LTAs in S. suis and suggest that this pathogen specifically modulates association with blood leukocytes through this modification of its surface.
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Affiliation(s)
- Sophie Öhlmann
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Ann-Kathrin Krieger
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Marita Meurer
- Institute for Biochemistry, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Nicole de Buhr
- Institute for Biochemistry, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Maren von Köckritz-Blickwede
- Institute for Biochemistry, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Nicole Schütze
- Institute of Immunology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Christoph Georg Baums
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
- *Correspondence: Christoph Georg Baums,
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9
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Aradanas M, Poljak Z, Fittipaldi N, Ricker N, Farzan A. Serotypes, Virulence-Associated Factors, and Antimicrobial Resistance of Streptococcus suis Isolates Recovered From Sick and Healthy Pigs Determined by Whole-Genome Sequencing. Front Vet Sci 2021; 8:742345. [PMID: 34796225 PMCID: PMC8593187 DOI: 10.3389/fvets.2021.742345] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/23/2021] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis is ubiquitous in swine, and yet, only a small percentage of pigs become clinically ill. The objective of this study was to describe the distribution of serotypes, virulence-associated factor (VAF), and antimicrobial resistance (AMR) genes in S. suis isolates recovered from systemic (blood, meninges, spleen, and lymph node) and non-systemic (tonsil, nasal cavities, ileum, and rectum) sites of sick and healthy pigs using whole-genome sequencing. In total, 273 S. suis isolates recovered from 112 pigs (47 isolates from systemic and 136 from non-systemic sites of 65 sick pigs; 90 isolates from non-systemic sites of 47 healthy pigs) on 17 Ontario farms were subjected to whole-genome sequencing. Using in silico typing, 21 serotypes were identified with serotypes 9 (13.9%) and 2 (8.4%) as the most frequent serotypes, whereas 53 (19.4%) isolates remained untypable. The relative frequency of VAF genes in isolates from systemic (Kruskal–Wallis, p < 0.001) and non-systemic (Kruskal–Wallis, p < 0.001) sites in sick pigs was higher compared with isolates from non-systemic sites in healthy pigs. Although many VAF genes were abundant in all isolates, three genes, including dltA [Fisher's test (FT), p < 0.001], luxS (FT, p = 0.01), and troA (FT, p = 0.02), were more prevalent in isolates recovered from systemic sites compared with non-systemic sites of pigs. Among the isolates, 98% had at least one AMR gene, and 79% had genes associated with at least four drug classes. The most frequently detected AMR genes were tetO conferring resistance to tetracycline and ermB conferring resistance to macrolide, lincosamide, and streptogramin. The wide distribution of VAFs genes in S. suis isolates in this study suggests that other host and environmental factors may contribute to S. suis disease development.
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Affiliation(s)
- Maverick Aradanas
- Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Zvonimir Poljak
- Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Nahuel Fittipaldi
- Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Nicole Ricker
- Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Abdolvahab Farzan
- Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.,Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
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10
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Brokaw A, Furuta A, Dacanay M, Rajagopal L, Adams Waldorf KM. Bacterial and Host Determinants of Group B Streptococcal Vaginal Colonization and Ascending Infection in Pregnancy. Front Cell Infect Microbiol 2021; 11:720789. [PMID: 34540718 PMCID: PMC8446444 DOI: 10.3389/fcimb.2021.720789] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/09/2021] [Indexed: 12/17/2022] Open
Abstract
Group B streptococcus (GBS) is a gram-positive bacteria that asymptomatically colonizes the vaginal tract. However, during pregnancy maternal GBS colonization greatly predisposes the mother and baby to a wide range of adverse outcomes, including preterm birth (PTB), stillbirth, and neonatal infection. Although many mechanisms involved in GBS pathogenesis are partially elucidated, there is currently no approved GBS vaccine. The development of a safe and effective vaccine that can be administered during or prior to pregnancy remains a principal objective in the field, because current antibiotic-based therapeutic strategies do not eliminate all cases of invasive GBS infections. Herein, we review our understanding of GBS disease pathogenesis at the maternal-fetal interface with a focus on the bacterial virulence factors and host defenses that modulate the outcome of infection. We follow GBS along its path from an asymptomatic colonizer of the vagina to an invasive pathogen at the maternal-fetal interface, noting factors critical for vaginal colonization, ascending infection, and vertical transmission to the fetus. Finally, at each stage of infection we emphasize important host-pathogen interactions, which, if targeted therapeutically, may help to reduce the global burden of GBS.
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Affiliation(s)
- Alyssa Brokaw
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Global Health, University of Washington, Seattle, WA, United States
| | - Anna Furuta
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Global Health, University of Washington, Seattle, WA, United States
| | - Matthew Dacanay
- Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, United States
| | - Lakshmi Rajagopal
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, United States.,Department of Global Health, University of Washington, Seattle, WA, United States.,Department of Pediatrics, University of Washington, Seattle, WA, United States
| | - Kristina M Adams Waldorf
- Department of Global Health, University of Washington, Seattle, WA, United States.,Department of Obstetrics & Gynecology, University of Washington, Seattle, WA, United States.,Department of Obstetrics and Gynecology, University of Washington and Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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11
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Abstract
When attempting to propagate infections, bacterial pathogens encounter phagocytes that encase them in vacuoles called phagosomes. Within phagosomes, bacteria are bombarded with a plethora of stresses that often lead to their demise. However, pathogens have evolved numerous strategies to counter those host defenses and facilitate survival. Given the importance of phagosome-bacteria interactions to infection outcomes, they represent a collection of targets that are of interest for next-generation antibacterials. To facilitate such therapies, different approaches can be employed to increase understanding of phagosome-bacteria interactions, and these can be classified broadly as top down (starting from intact systems and breaking down the importance of different parts) or bottom up (developing a knowledge base on simplified systems and progressively increasing complexity). Here we review knowledge of phagosomal compositions and bacterial survival tactics useful for bottom-up approaches, which are particularly relevant for the application of reaction engineering to quantify and predict the time evolution of biochemical species in these death-dealing vacuoles. Further, we highlight how understanding in this area can be built up through the combination of immunology, microbiology, and engineering.
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Affiliation(s)
- Darshan M Sivaloganathan
- Program in Quantitative and Computational Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Mark P Brynildsen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA;
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12
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Gram Positive Bacterial Lipoteichoic Acid Role in a Root Canal Infection – A Literature Review. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2021. [DOI: 10.22207/jpam.15.2.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria and its by-products are found to be the main cause of pulpal and periapical infection of tooth. Infected root canals of tooth harbours a wide variation of microbial flora that includes both Gram-positive and Gram-negative microorganisms. Bacterial components such as Lipopolysaccharide (LPS) of gram negative bacteria and Lipoteichoic Acid (LTA) of gram positive bacteria have the potential to enter the peri-apical tissue of tooth and initiate the inflammatory process. After microbial death that occurs either due to body’s defence cells or by antibiotic action, bacterial cell wall components such as LTA are released which can persist inside macrophages for prolonged periods causing chronic inflammation. Once these cell-wall components are recognized by the body immune surveillance cells, numerous inflammatory mediators are released leading to inflammation and subsequent pathological consequences. The purpose of this review is intend to summarize the role of gram positive bacterial component LTA in causing endodontic infection and use of potential therapeutic agents against LTA.
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13
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Assoni L, Milani B, Carvalho MR, Nepomuceno LN, Waz NT, Guerra MES, Converso TR, Darrieux M. Resistance Mechanisms to Antimicrobial Peptides in Gram-Positive Bacteria. Front Microbiol 2020; 11:593215. [PMID: 33193264 PMCID: PMC7609970 DOI: 10.3389/fmicb.2020.593215] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/03/2020] [Indexed: 02/06/2023] Open
Abstract
With the alarming increase of infections caused by pathogenic multidrug-resistant bacteria over the last decades, antimicrobial peptides (AMPs) have been investigated as a potential treatment for those infections, directly through their lytic effect or indirectly, due to their ability to modulate the immune system. There are still concerns regarding the use of such molecules in the treatment of infections, such as cell toxicity and host factors that lead to peptide inhibition. To overcome these limitations, different approaches like peptide modification to reduce toxicity and peptide combinations to improve therapeutic efficacy are being tested. Human defense peptides consist of an important part of the innate immune system, against a myriad of potential aggressors, which have in turn developed different ways to overcome the AMPs microbicidal activities. Since the antimicrobial activity of AMPs vary between Gram-positive and Gram-negative species, so do the bacterial resistance arsenal. This review discusses the mechanisms exploited by Gram-positive bacteria to circumvent killing by antimicrobial peptides. Specifically, the most clinically relevant genera, Streptococcus spp., Staphylococcus spp., Enterococcus spp. and Gram-positive bacilli, have been explored.
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Affiliation(s)
- Lucas Assoni
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Barbara Milani
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Marianna Ribeiro Carvalho
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Lucas Natanael Nepomuceno
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Natalha Tedeschi Waz
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Maria Eduarda Souza Guerra
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Thiago Rojas Converso
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Michelle Darrieux
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
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14
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Zhang Z, Li Y, Hu M, Yu A. Genome reanalysis to decipher resistome, virulome, and attenuated characters of attenuated Streptococcus agalactiae strain HZAUSC001. Microb Pathog 2020; 147:104416. [PMID: 32745666 DOI: 10.1016/j.micpath.2020.104416] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/11/2020] [Accepted: 07/20/2020] [Indexed: 10/23/2022]
Abstract
Streptococcus agalactiae is a serious pathogen causing severe anthropozoonosis in a broad range of hosts, from aquatic animals to mammals, including humans. S. agalactiae HZAUSC001 was isolated from a moribund tilapia fish exhibiting classic clinical symptoms of streptococcosis in Zhanjiang, Guangdong, China. And it was identified as the etiological factor resulting in fish disease, but was notable because it exhibited attenuated virulence. Here, the genome of S. agalactiae HZAUSC001 was re-analyzed; we assessed the resistome and virulome and deciphered the attenuated characters of HZAUSC001. The S. agalactiae HZAUSC001 genome was assembled into one chromosome with a GC-content of 35.37% and 1972 predicted open reading frames (ORFs). Phylogenetic analysis indicated that it is evolutionarily similar to piscine GBS strains GD201008-001 and ZQ0910. After re-analyzing the published genomic sequence of HZAUSC001, we identified 38 virulence factor genes and one antibiotic-resistance gene. Note that three previously noted virulence genes, bca (C protein alpha-antigen), cpbA (choline-binding protein A) and esp (enterococcal surface protein), were absent in the virulence-attenuated strain S. agalactiae HZAUSC001 but present in the highly virulent strain S. agalactiae GD201008-001. We speculate that the absence of these three virulence genes may be associated with the attenuated traits of the HZAUSC001 strain. Collectively, our study supports that HZAUSC001 may be an excellent candidate for development of an attenuated vaccine, and our results contribute to further understanding of GBS epidemiology and surveillance targets.
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Affiliation(s)
- Ze Zhang
- College of Life Sciences, Beijing Normal University, Beijing, 100875, China; National Institute of Biological Sciences, Zhongguancun Life Science Park, Changping, 102206, Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, 102206, Beijing, China.
| | - Yuhui Li
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Minqiang Hu
- School of Chemical Biology and Biotechnology, Shenzhen Graduate School, Peking University, Shenzhen, 518055, China
| | - Angen Yu
- Department of Aquatic Animal Medicine, Research Center for Marine Biology, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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15
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John PP, Baker BC, Paudel S, Nassour L, Cagle H, Kulkarni R. Exposure to Moderate Glycosuria Induces Virulence of Group B Streptococcus. J Infect Dis 2020; 223:843-847. [PMID: 32702082 DOI: 10.1093/infdis/jiaa443] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 07/17/2020] [Indexed: 12/26/2022] Open
Abstract
To explore whether glycosuria induces virulence of uropathogens, in turn facilitating urinary tract infection (UTI), we exposed group B Streptococcus (GBS) strain 10/84 to human urine plain or with 300 mg/dL glucose (mimicking moderate glycosuria). Exposure to moderate glycosuria significantly augmented bacterial growth, kidney bacterial burden in a mouse model of ascending UTI, and virulence characteristics and expression of corresponding genes. Exposure to glycosuria increased GBS adherence to human bladder epithelial cell line and expression of corresponding PI2a fimbrial gene, antimicrobial peptide LL-37 resistance and bacterial surface charge modulating dltA, and GBS hemolytic ability and expression of genes encoding pore-forming toxins.
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Affiliation(s)
- Preeti P John
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Brady C Baker
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Santosh Paudel
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Lauren Nassour
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Hayden Cagle
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Ritwij Kulkarni
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
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16
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Two-Component Signal Transduction Systems in the Human Pathogen Streptococcus agalactiae. Infect Immun 2020; 88:IAI.00931-19. [PMID: 31988177 DOI: 10.1128/iai.00931-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Streptococcus agalactiae (group B Streptococcus [GBS]) is an important cause of invasive infection in newborns, maternal women, and older individuals with underlying chronic illnesses. GBS has many mechanisms to adapt and survive in its host, and these mechanisms are often controlled via two-component signal transduction systems. In GBS, more than 20 distinct two-component systems (TCSs) have been classified to date, consisting of canonical TCSs as well as orphan and atypical sensors and regulators. These signal transducing systems are necessary for metabolic regulation, resistance to antibiotics and antimicrobials, pathogenesis, and adhesion to the mucosal surfaces to colonize the host. This minireview discusses the structures of these TCSs in GBS as well as how selected systems regulate essential cellular processes such as survival and colonization. GBS contains almost double the number of TCSs compared to the closely related Streptococcus pyogenes and Streptococcus pneumoniae, and while research on GBS TCSs has been increasing in recent years, no comprehensive reviews of these TCSs exist, making this review especially relevant.
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17
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Multiple ways to kill bacteria via inhibiting novel cell wall or membrane targets. Future Med Chem 2020; 12:1253-1279. [PMID: 32538147 DOI: 10.4155/fmc-2020-0046] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The rise of antibiotic-resistant infections has been well documented and the need for novel antibiotics cannot be overemphasized. US FDA approved antibiotics target only a small fraction of bacterial cell wall or membrane components, well-validated antimicrobial targets. In this review, we highlight small molecules that inhibit relatively unexplored cell wall and membrane targets. Some of these targets include teichoic acids-related proteins (DltA, LtaS, TarG and TarO), lipid II, Mur family enzymes, components of LPS assembly (MsbA, LptA, LptB and LptD), penicillin-binding protein 2a in methicillin-resistant Staphylococcus aureus, outer membrane protein transport (such as LepB and BamA) and lipoprotein transport components (LspA, LolC, LolD and LolE). Inhibitors of SecA, cell division protein, FtsZ and compounds that kill persister cells via membrane targeting are also covered.
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18
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Wu F, Tan C. Dead bacterial absorption of antimicrobial peptides underlies collective tolerance. J R Soc Interface 2020; 16:20180701. [PMID: 30958185 DOI: 10.1098/rsif.2018.0701] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The collective tolerance towards antimicrobial peptides (APs) is thought to occur primarily through mechanisms associated with live bacterial cells. In contrast to the focus on live cells, we discover that the LL37 antimicrobial peptide kills a subpopulation of Escherichia coli, forming dead cells that absorb the remaining LL37 from the environment. Combining mathematical modelling with population and single-cell experiments, we show that bacteria absorb LL37 at a timing that coincides with the permeabilization of their cytoplasmic membranes. Furthermore, we show that one bacterial strain can absorb LL37 and protect another strain from killing by LL37. Finally, we demonstrate that the absorption of LL37 by dead bacteria can be reduced using a peptide adjuvant. In contrast to the known collective tolerance mechanisms, we show that the absorption of APs by dead bacteria is a dynamic process that leads to emergent population behaviour.
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Affiliation(s)
- Fan Wu
- Department of Biomedical Engineering, University of California Davis , Davis, CA 95616 , USA
| | - Cheemeng Tan
- Department of Biomedical Engineering, University of California Davis , Davis, CA 95616 , USA
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19
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Abdi M, Mirkalantari S, Amirmozafari N. Bacterial resistance to antimicrobial peptides. J Pept Sci 2019; 25:e3210. [DOI: 10.1002/psc.3210] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/04/2019] [Accepted: 07/21/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Milad Abdi
- Student Research Committee, Faculty of MedicineIran University of Medical Sciences Tehran Iran
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
| | - Shiva Mirkalantari
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
| | - Nour Amirmozafari
- Department of Microbiology, Faculty of MedicineIran University of Medical Sciences Tehran Iran
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20
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Armistead B, Oler E, Adams Waldorf K, Rajagopal L. The Double Life of Group B Streptococcus: Asymptomatic Colonizer and Potent Pathogen. J Mol Biol 2019; 431:2914-2931. [PMID: 30711542 DOI: 10.1016/j.jmb.2019.01.035] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 12/22/2022]
Abstract
Group B streptococcus (GBS) is a β-hemolytic gram-positive bacterium that colonizes the lower genital tract of approximately 18% of women globally as an asymptomatic member of the gastrointestinal and/or vaginal flora. If established in other host niches, however, GBS is highly pathogenic. During pregnancy, ascending GBS infection from the vagina to the intrauterine space is associated with preterm birth, stillbirth, and fetal injury. In addition, vertical transmission of GBS during or after birth results in life-threatening neonatal infections, including pneumonia, sepsis, and meningitis. Although the mechanisms by which GBS traffics from the lower genital tract to vulnerable host niches are not well understood, recent advances have revealed that many of the same bacterial factors that promote asymptomatic vaginal carriage also facilitate dissemination and virulence. Furthermore, highly pathogenic GBS strains have acquired unique factors that enhance survival in invasive niches. Several host factors also exist that either subdue GBS upon vaginal colonization or alternatively permit invasive infection. This review summarizes the GBS and host factors involved in GBS's state as both an asymptomatic colonizer and an invasive pathogen. Gaining a better understanding of these mechanisms is key to overcoming the challenges associated with vaccine development and identification of novel strategies to mitigate GBS virulence.
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Affiliation(s)
- Blair Armistead
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle 98101, WA, USA
| | - Elizabeth Oler
- Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle 98195, WA, USA
| | - Kristina Adams Waldorf
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle 98195, WA, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle 98109, WA, USA; Sahlgrenska Academy, Gothenburg University, Gothenburg 413 90, Sweden
| | - Lakshmi Rajagopal
- Department of Global Health, University of Washington, Seattle 98195, WA, USA; Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle 98101, WA, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle 98195, WA, USA.
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21
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Yang Y, Luo M, Zhou H, Li C, Luk A, Zhao G, Fung K, Ip M. Role of Two-Component System Response Regulator bceR in the Antimicrobial Resistance, Virulence, Biofilm Formation, and Stress Response of Group B Streptococcus. Front Microbiol 2019; 10:10. [PMID: 30728810 PMCID: PMC6351488 DOI: 10.3389/fmicb.2019.00010] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 01/07/2019] [Indexed: 01/31/2023] Open
Abstract
Group B Streptococcus (GBS; Streptococcus agalactiae) is a leading cause of sepsis in neonates and pregnant mothers worldwide. Whereas the hyper-virulent serogroup III clonal cluster 17 has been associated with neonatal disease and meningitis, serogroup III ST283 was recently implicated in invasive disease among non-pregnant adults in Asia. Here, through comparative genome analyses of invasive and non-invasive ST283 strains, we identified a truncated DNA-binding regulator of a two-component system in a non-invasive strain that was homologous to Bacillus subtilis bceR, encoding the bceRSAB response regulator, which was conserved among GBS strains. Using isogenic knockout and complementation mutants of the ST283 strain, we demonstrated that resistance to bacitracin and the human antimicrobial peptide cathelicidin LL-37 was reduced in the ΔbceR strain with MICs changing from 64 and 256 μg/ml to 0.25 and 64 μg/ml, respectively. Further, the ATP-binding cassette transporter was upregulated by sub-inhibitory concentrations of bacitracin in the wild-type strain. Upregulation of dltA in the wild-type strain was also observed and thought to explain the increased resistance to antimicrobial peptides. DltA, an enzyme involved in D-alanylation during the synthesis of wall teichoic acids, which mediates reduced antimicrobial susceptibility, was previously shown to be regulated by the bceR-type regulator in Staphylococcus aureus. In a murine infection model, we found that the ΔbceR mutation significantly reduced the mortality rate compared to that with the wild-type strain (p < 0.01). Moreover, this mutant was more susceptible to oxidative stress compared to the wild-type strain (p < 0.001) and was associated with reduced biofilm formation (p < 0.0001). Based on 2-DGE and mass spectrometry, we showed that downregulation of alkyl hydroperoxide reductase (AhpC), a Gls24 family stress protein, and alcohol dehydrogenase (Adh) in the ΔbceR strain might explain the attenuated virulence and compromised stress response. Together, we showed for the first time that the bceR regulator in GBS plays an important role in bacitracin and antimicrobial peptide resistance, virulence, survival under oxidative stress, and biofilm formation.
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Affiliation(s)
- Ying Yang
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Mingjing Luo
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Haokui Zhou
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Carmen Li
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Alison Luk
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - GuoPing Zhao
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Kitty Fung
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Margaret Ip
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, Hong Kong
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22
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Hirt H, Hall JW, Larson E, Gorr SU. A D-enantiomer of the antimicrobial peptide GL13K evades antimicrobial resistance in the Gram positive bacteria Enterococcus faecalis and Streptococcus gordonii. PLoS One 2018; 13:e0194900. [PMID: 29566082 PMCID: PMC5864073 DOI: 10.1371/journal.pone.0194900] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/12/2018] [Indexed: 11/18/2022] Open
Abstract
Antimicrobial peptides represent an alternative to traditional antibiotics that may be less susceptible to bacterial resistance mechanisms by directly attacking the bacterial cell membrane. However, bacteria have a variety of defense mechanisms that can prevent cationic antimicrobial peptides from reaching the cell membrane. The L- and D-enantiomers of the antimicrobial peptide GL13K were tested against the Gram-positive bacteria Enterococcus faecalis and Streptococcus gordonii to understand the role of bacterial proteases and cell wall modifications in bacterial resistance. GL13K was derived from the human salivary protein BPIFA2. Minimal inhibitory concentrations were determined by broth dilution and a serial assay used to determine bacterial resistance. Peptide degradation was determined in a bioassay utilizing a luminescent strain of Pseudomonas aeruginosa to detect peptide activity. Autolysis and D-alanylation-deficient strains of E. faecalis and S. gordonii were tested in autolysis assays and peptide activity assays. E. faecalis protease inactivated L-GL13K but not D-GL13K, whereas autolysis did not affect peptide activity. Indeed, the D-enantiomer appeared to kill the bacteria prior to initiation of autolysis. D-alanylation mutants were killed by L-GL13K whereas this modification did not affect killing by D-GL13K. The mutants regained resistance to L-GL13K whereas bacteria did not gain resistance to D-GL13K after repeated treatment with the peptides. D-alanylation affected the hydrophobicity of bacterial cells but hydrophobicity alone did not affect GL13K activity. D-GL13K evades two resistance mechanisms in Gram-positive bacteria without giving rise to substantial new resistance. D-GL13K exhibits attractive properties for further antibiotic development.
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Affiliation(s)
- Helmut Hirt
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - Jeffrey W. Hall
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - Elliot Larson
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
| | - Sven-Ulrik Gorr
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, Minnesota, United States of America
- * E-mail:
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23
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Kamar R, Réjasse A, Jéhanno I, Attieh Z, Courtin P, Chapot-Chartier MP, Nielsen-Leroux C, Lereclus D, El Chamy L, Kallassy M, Sanchis-Borja V. DltX of Bacillus thuringiensis Is Essential for D-Alanylation of Teichoic Acids and Resistance to Antimicrobial Response in Insects. Front Microbiol 2017; 8:1437. [PMID: 28824570 PMCID: PMC5541007 DOI: 10.3389/fmicb.2017.01437] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/14/2017] [Indexed: 11/13/2022] Open
Abstract
The dlt operon of Gram-positive bacteria is required for the incorporation of D-alanine esters into cell wall-associated teichoic acids (TAs). Addition of D-alanine to TAs reduces the negative charge of the cell envelope thereby preventing cationic antimicrobial peptides (CAMPs) from reaching their target of action on the bacterial surface. In most gram-positive bacteria, this operon consists of five genes dltXABCD but the involvement of the first ORF (dltX) encoding a small protein of unknown function, has never been investigated. The aim of this study was to establish whether this protein is involved in the D-alanylation process in Bacillus thuringiensis. We, therefore constructed an in frame deletion mutant of dltX, without affecting the expression of the other genes of the operon. The growth characteristics of the dltX mutant and those of the wild type strain were similar under standard in vitro conditions. However, disruption of dltX drastically impaired the resistance of B. thuringiensis to CAMPs and significantly attenuated its virulence in two insect species. Moreover, high-performance liquid chromatography studies showed that the dltX mutant was devoid of D-alanine, and electrophoretic mobility measurements indicated that the cells carried a higher negative surface charge. Scanning electron microscopy experiments showed morphological alterations of these mutant bacteria, suggesting that depletion of D-alanine from TAs affects cell wall structure. Our findings suggest that DltX is essential for the incorporation of D-alanyl esters into TAs. Therefore, DltX plays a direct role in the resistance to CAMPs, thus contributing to the survival of B. thuringiensis in insects. To our knowledge, this work is the first report examining the involvement of dltX in the D-alanylation of TAs.
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Affiliation(s)
- Rita Kamar
- INRA, UMR1319 MicalisJouy-en-Josas, France.,AgroParisTech, UMR MicalisJouy-en-Josas, France.,Laboratoire de Génétique de la Drosophile et Virulence Microbienne, Université Saint-JosephBeirut, Lebanon
| | - Agnès Réjasse
- INRA, UMR1319 MicalisJouy-en-Josas, France.,AgroParisTech, UMR MicalisJouy-en-Josas, France
| | - Isabelle Jéhanno
- INRA, UMR1319 MicalisJouy-en-Josas, France.,AgroParisTech, UMR MicalisJouy-en-Josas, France
| | - Zaynoun Attieh
- Laboratoire de Génétique de la Drosophile et Virulence Microbienne, Université Saint-JosephBeirut, Lebanon
| | - Pascal Courtin
- INRA, UMR1319 MicalisJouy-en-Josas, France.,AgroParisTech, UMR MicalisJouy-en-Josas, France
| | | | | | - Didier Lereclus
- INRA, UMR1319 MicalisJouy-en-Josas, France.,AgroParisTech, UMR MicalisJouy-en-Josas, France
| | - Laure El Chamy
- Laboratoire de Génétique de la Drosophile et Virulence Microbienne, Université Saint-JosephBeirut, Lebanon
| | - Mireille Kallassy
- Laboratoire de Génétique de la Drosophile et Virulence Microbienne, Université Saint-JosephBeirut, Lebanon
| | - Vincent Sanchis-Borja
- INRA, UMR1319 MicalisJouy-en-Josas, France.,AgroParisTech, UMR MicalisJouy-en-Josas, France
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24
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Transcriptome analysis of Streptococcus gallolyticus subsp. gallolyticus in interaction with THP-1 macrophage-like cells. PLoS One 2017; 12:e0180044. [PMID: 28672015 PMCID: PMC5495212 DOI: 10.1371/journal.pone.0180044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 06/08/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Streptococcus gallolyticus subsp. gallolyticus (S. gallolyticus) is a pathogen of infective endocarditis. It was observed previously that this bacterium survives longer in macrophages than other species and the phagocytic uptake by and survival in THP-1 macrophages is strain-dependent. METHODS The phagocytosis assay was performed with THP-1 macrophages. S. gallolyticus specific whole genome microarrays were used for transcriptome analysis. RESULTS Better survival in macrophages was observed for UCN34, BAA-2069 and ATCC43143 than for DSM16831 and LMG17956. S. gallolyticus strains show high resistance to tested bactericidal agents (acid, lysozyme and hydrogen peroxide). S. gallolyticus stimulates significant lower cytokine gene expression and causes less lysis of macrophages compared to the control strain Staphylococcus aureus. S. gallolyticus reacts to oxidative burst with a higher gene expression of NADH oxidase initially at the early phase. Expression of genes involved in D-alanylation of teichoic acid, carbohydrate metabolism and transport systems were upregulated thereafter. CONCLUSION S. gallolyticus is very resistant to bactericidal agents normally causing degradation of bacteria in phagolysosomes. Additionally, the D-alanylation of teichoic acid is an important factor for survival.
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25
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Arena MP, Capozzi V, Spano G, Fiocco D. The potential of lactic acid bacteria to colonize biotic and abiotic surfaces and the investigation of their interactions and mechanisms. Appl Microbiol Biotechnol 2017; 101:2641-2657. [PMID: 28213732 DOI: 10.1007/s00253-017-8182-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/01/2017] [Accepted: 02/03/2017] [Indexed: 12/23/2022]
Abstract
Lactic acid bacteria (LAB) are a heterogeneous group of Gram-positive bacteria that comprise several species which have evolved in close association with humans (food and lifestyle). While their use to ferment food dates back to very ancient times, in the last decades, LAB have attracted much attention for their documented beneficial properties and for potential biomedical applications. Some LAB are commensal that colonize, stably or transiently, host mucosal surfaces, inlcuding the gut, where they may contribute to host health. In this review, we present and discuss the main factors enabling LAB adaptation to such lifestyle, including the gene reprogramming accompanying gut colonization, the specific bacterial components involved in adhesion and interaction with host, and how the gut niche has shaped the genome of intestine-adapted species. Moreover, the capacity of LAB to colonize abiotic surfaces by forming structured communities, i.e., biofilms, is briefly discussed, taking into account the main bacterial and environmental factors involved, particularly in relation to food-related environments. The vast spread of LAB surface-associated communities and the ability to control their occurrence hold great potentials for human health and food safety biotechnologies.
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Affiliation(s)
- Mattia Pia Arena
- Department of Agriculture, Food and Environment Sciences, University of Foggia, via Napoli 25, 71122, Foggia, Italy
| | - Vittorio Capozzi
- Department of Agriculture, Food and Environment Sciences, University of Foggia, via Napoli 25, 71122, Foggia, Italy
| | - Giuseppe Spano
- Department of Agriculture, Food and Environment Sciences, University of Foggia, via Napoli 25, 71122, Foggia, Italy.
| | - Daniela Fiocco
- Department of Clinical and Experimental Medicine, University of Foggia, Viale Pinto 1, 71122, Foggia, Italy
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26
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Parker RE, Knupp D, Al Safadi R, Rosenau A, Manning SD. Contribution of the RgfD Quorum Sensing Peptide to rgf Regulation and Host Cell Association in Group B Streptococcus. Genes (Basel) 2017; 8:genes8010023. [PMID: 28067833 PMCID: PMC5295018 DOI: 10.3390/genes8010023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/29/2016] [Accepted: 01/04/2017] [Indexed: 11/16/2022] Open
Abstract
Streptococcus agalactiae (group B Streptococcus; GBS) is a common inhabitant of the genitourinary and/or gastrointestinal tract in up to 40% of healthy adults; however, this opportunistic pathogen is able to breach restrictive host barriers to cause disease and persist in harsh and changing conditions. This study sought to identify a role for quorum sensing, a form of cell to cell communication, in the regulation of the fibrinogen-binding (rgfBDAC) two-component system and the ability to associate with decidualized endometrial cells in vitro. To do this, we created a deletion in rgfD, which encodes the putative autoinducing peptide, in a GBS strain belonging to multilocus sequence type (ST)-17 and made comparisons to the wild type. Sequence variation in the rgf operon was detected in 40 clinical strains and a non-synonymous single nucleotide polymorphism was detected in rgfD in all of the ST-17 genomes that resulted in a truncation. Using qPCR, expression of rgf operon genes was significantly decreased in the ST-17 ΔrgfD mutant during exponential growth with the biggest difference (3.3-fold) occurring at higher cell densities. Association with decidualized endometrial cells was decreased 1.3-fold in the mutant relative to the wild type and rgfC expression was reduced 22-fold in ΔrgfD following exposure to the endometrial cells. Collectively, these data suggest that this putative quorum sensing molecule is important for attachment to human tissues and demonstrate a role for RgfD in GBS pathogenesis through regulation of rgfC.
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Affiliation(s)
- Robert E Parker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
| | - David Knupp
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
| | - Rim Al Safadi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
| | - Agnѐs Rosenau
- Infectiologie et Santé Publique ISP, Institut National de la Recherche Agronomique, Université de Tours, Equipe Bactéries et Risque Materno-fœtal, UMR1282 Tours, France.
| | - Shannon D Manning
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
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Abstract
Antimicrobial peptides (AMPs), also known as host defense peptides, are small naturally occurring microbicidal molecules produced by the host innate immune response that function as a first line of defense to kill pathogenic microorganisms by inducing deleterious cell membrane damage. AMPs also possess signaling and chemoattractant activities and can modulate the innate immune response to enhance protective immunity or suppress inflammation. Human pathogens have evolved defense molecules and strategies to counter and survive the AMPs released by host immune cells such as neutrophils and macrophages. Here, we review the various mechanisms used by human bacterial pathogens to resist AMP-mediated killing, including surface charge modification, active efflux, alteration of membrane fluidity, inactivation by proteolytic digestion, and entrapment by surface proteins and polysaccharides. Enhanced understanding of AMP resistance at the molecular level may offer insight into the mechanisms of bacterial pathogenesis and augment the discovery of novel therapeutic targets and drug design for the treatment of recalcitrant multidrug-resistant bacterial infections.
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28
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Santos-Sierra S, Golenbock DT, Henneke P. Toll-like receptor-dependent discrimination of streptococci. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519060120050601] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Streptococcus pneumoniae and Streptococcus agalactiae cause distinct infectious diseases in small children. Similarly, these bacteria elicit very different host-cell responses in vitro. Inactivated S. agalactiae by far exceeds S. pneumoniae in the activation of inflammatory cytokines and upstream signaling intermediates such as the MAP kinase JNK. The inflammatory response to both Streptococcus spp. is mediated by MyD88, an essential adapter protein of Toll-like receptors (TLRs), although the specific TLRs that are involved have not been fully resolved. Furthermore, during logarithmic growth, S. pneumoniae releases pneumolysin that interacts with TLR4 whereas S. agalactiae releases diacylated molecules that interact with TLR2/6. Interaction of these soluble bacterial products with their cognate TLRs is critical for limiting bacterial dissemination and and systemic inflammation in mice. This might be due, in part, to TLR-mediated apoptosis induced by these factors. In conclusion related streptococcal species induce specific events in TLR-mediated signal transduction. Comparative analysis of the host-cell response to these bacteria reveals molecules such as JNK as valuable targets for adjunctive sepsis therapy.
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Affiliation(s)
| | - Douglas T. Golenbock
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Philipp Henneke
- Division of Infectious Diseases, Children's Hospital, Freiburg, Germany, philipp.henneke@ uniklinik-freiburg.de
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29
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Andersson D, Hughes D, Kubicek-Sutherland J. Mechanisms and consequences of bacterial resistance to antimicrobial peptides. Drug Resist Updat 2016; 26:43-57. [DOI: 10.1016/j.drup.2016.04.002] [Citation(s) in RCA: 319] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 10/21/2022]
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30
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Malanovic N, Lohner K. Gram-positive bacterial cell envelopes: The impact on the activity of antimicrobial peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:936-46. [DOI: 10.1016/j.bbamem.2015.11.004] [Citation(s) in RCA: 249] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 12/21/2022]
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31
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Dang G, Cao J, Cui Y, Song N, Chen L, Pang H, Liu S. Characterization of Rv0888, a Novel Extracellular Nuclease from Mycobacterium tuberculosis. Sci Rep 2016; 6:19033. [PMID: 26742696 PMCID: PMC4733049 DOI: 10.1038/srep19033] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/02/2015] [Indexed: 02/07/2023] Open
Abstract
Bacterial extracellular nucleases play important roles in virulence, biofilm formation, utilization of extracellular DNA as a nutrient, and degradation of neutrophil DNA extracellular traps. However, there is no current data available for extracellular nucleases derived from M. tuberculosis. Herein, we have identified and characterized Rv0888, an extracellular nuclease in M. tuberculosis. The protein was overexpressed in E. coli, and the purified Rv0888 protein was found to require divalent cations for activity, with an optimal temperature and pH of 41 °C and 6.5, respectively. Further results demonstrated that Rv0888 nuclease activity could be inhibited by four Chinese medicine monomers. Based on sequence analysis, Rv0888 nuclease exhibited no homology with any known extracellular nucleases, indicating that Rv0888 is a novel nuclease. Site-directed mutagenesis studies revealed that the H353, D387, and D438 residues play catalytic roles in Rv0888. In vivo infection studies confirmed that Rv0888 is required for infection and is related to pathogenicity, as the persistent ability of recombinant Mycobacterium smegmatis (rMS) Rv0888NS/MS and Rv0888S/MS is significantly higher than pMV262/MS in the lung tissue, and the Rv0888NS/MS and Rv0888S/MS could produce pathological changes in the mice lung. These results show that Rv0888 is relevant to pathogenicity of M. tuberculosis.
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Affiliation(s)
- Guanghui Dang
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Jun Cao
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Yingying Cui
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Ningning Song
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Liping Chen
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Hai Pang
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Siguo Liu
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
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32
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Pasquina L, Maria JPS, Wood BM, Moussa SH, Matano L, Santiago M, Martin SES, Lee W, Meredith TC, Walker S. A synthetic lethal approach for compound and target identification in Staphylococcus aureus. Nat Chem Biol 2016; 12:40-5. [PMID: 26619249 PMCID: PMC4684722 DOI: 10.1038/nchembio.1967] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 10/14/2015] [Indexed: 01/12/2023]
Abstract
The majority of bacterial proteins are dispensable for growth in the laboratory but nevertheless have important physiological roles. There are no systematic approaches to identify cell-permeable small-molecule inhibitors of these proteins. We demonstrate a strategy to identify such inhibitors that exploits synthetic lethal relationships both for small-molecule discovery and for target identification. Applying this strategy in Staphylococcus aureus, we have identified a compound that inhibits DltB, a component of the teichoic acid D-alanylation machinery that has been implicated in virulence. This D-alanylation inhibitor sensitizes S. aureus to aminoglycosides and cationic peptides and is lethal in combination with a wall teichoic acid inhibitor. We conclude that DltB is a druggable target in the D-alanylation pathway. More broadly, the work described demonstrates a systematic method to identify biologically active inhibitors of major bacterial processes that can be adapted to numerous organisms.
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Affiliation(s)
- Lincoln Pasquina
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - John P. Santa Maria
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - B. McKay Wood
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Samir H. Moussa
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Leigh Matano
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Marina Santiago
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Sara E. S. Martin
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Wonsik Lee
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Timothy C. Meredith
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
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33
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The functional dlt operon of Clostridium butyricum controls the d-alanylation of cell wall components and influences cell septation and vancomycin-induced lysis. Anaerobe 2015; 35:105-14. [DOI: 10.1016/j.anaerobe.2015.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 09/04/2015] [Accepted: 09/07/2015] [Indexed: 02/05/2023]
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34
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Flores-Kim J, Darwin AJ. Regulation of bacterial virulence gene expression by cell envelope stress responses. Virulence 2015; 5:835-51. [PMID: 25603429 DOI: 10.4161/21505594.2014.965580] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The bacterial cytoplasm lies within a multilayered envelope that must be protected from internal and external hazards. This protection is provided by cell envelope stress responses (ESRs), which detect threats and reprogram gene expression to ensure survival. Pathogens frequently need these ESRs to survive inside the host, where their envelopes face dangerous environmental changes and attack from antimicrobial molecules. In addition, some virulence genes have become integrated into ESR regulons. This might be because these genes can protect the cell envelope from damage by host molecules, or it might help ESRs to reduce stress by moderating the assembly of virulence factors within the envelope. Alternatively, it could simply be a mechanism to coordinate the induction of virulence gene expression with entry into the host. Here, we briefly describe some of the bacterial ESRs, followed by examples where they control virulence gene expression in both Gram-negative and Gram-positive pathogens.
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Key Words
- BFP, bundle-forming pilus
- CAMP, cationic antimicrobial peptide
- CF, cystic fibrosis
- ECF, extracytoplasmic function
- EPEC, enteropathogenic E. coli
- ESR, envelope stress response
- HMV, hypermucoviscosity
- IM, inner membrane
- LPS, lipopolysaccharide
- LTA, lipoteichoic acids
- OM, outer membrane
- OMP, outer membrane protein
- PG, phosphatidylglycerol
- T(2/3/4)SS, type II/III/IV secretion system
- UPEC, uropathogenic E. coli
- WTA, wall teichoic acids
- antimicrobial peptide
- bacterial pathogens
- cell envelope
- gene regulation
- peptidoglycan
- phospholipid
- stress response
- teichoic acid
- virulence gene
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Affiliation(s)
- Josué Flores-Kim
- a Department of Microbiology ; New York University School of Medicine ; New York , NY USA
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35
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Mucosal physical and chemical innate barriers: Lessons from microbial evasion strategies. Semin Immunol 2015; 27:111-8. [PMID: 25936225 DOI: 10.1016/j.smim.2015.03.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/13/2015] [Indexed: 12/24/2022]
Abstract
The innate immune system has evolved since millions of years under a selective pressure. Among the different host mechanisms selected and conserved as a first line of defense, the gastrointestinal mucus layer constitutes an efficient physical and chemical barrier against invading microbes. Mucin glycoproteins and antimicrobial peptides are the major components of the mucus barrier, and evidences prove that they form an effective protection against most microbes. However, successful pathogens have evolved evasion strategies to circumvent this defense barrier. Here, we discuss the interactions between pathogens, mucins, and antimicrobial peptides, and the mechanisms that pathogens have developed to evade the innate defense systems of the intestinal mucosal barrier.
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36
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Bauer ME, Shafer WM. On the in vivo significance of bacterial resistance to antimicrobial peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:3101-11. [PMID: 25701234 DOI: 10.1016/j.bbamem.2015.02.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 02/04/2015] [Accepted: 02/07/2015] [Indexed: 12/17/2022]
Abstract
Antimicrobial peptides (AMPs) are at the front-line of host defense during infection and play critical roles both in reducing the microbial load early during infection and in linking innate to adaptive immunity. However, successful pathogens have developed mechanisms to resist AMPs. Although considerable progress has been made in elucidating AMP-resistance mechanisms of pathogenic bacteria in vitro, less is known regarding the in vivo significance of such resistance. Nevertheless, progress has been made in this area, largely by using murine models and, in two instances, human models of infection. Herein, we review progress on the use of in vivo infection models in AMP research and discuss the AMP resistance mechanisms that have been established by in vivo studies to contribute to microbial infection. We posit that in vivo infection models are essential tools for investigators to understand the significance to pathogenesis of genetic changes that impact levels of bacterial susceptibility to AMPs. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.
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Affiliation(s)
- Margaret E Bauer
- Department of Microbiology and Immunology, Indiana University School of Medicine, 635 Barnhill Drive MS-420, Indianapolis, IN 46254, USA.
| | - William M Shafer
- Laboratories of Bacterial Pathogenesis, Veterans Affairs Medical Center, Decatur, GA 30033, USA; Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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37
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LaRock CN, Nizet V. Cationic antimicrobial peptide resistance mechanisms of streptococcal pathogens. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:3047-54. [PMID: 25701232 DOI: 10.1016/j.bbamem.2015.02.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/04/2015] [Accepted: 02/07/2015] [Indexed: 02/06/2023]
Abstract
Cationic antimicrobial peptides (CAMPs) are critical front line contributors to host defense against invasive bacterial infection. These immune factors have direct killing activity toward microbes, but many pathogens are able to resist their effects. Group A Streptococcus, group B Streptococcus and Streptococcus pneumoniae are among the most common pathogens of humans and display a variety of phenotypic adaptations to resist CAMPs. Common themes of CAMP resistance mechanisms among the pathogenic streptococci are repulsion, sequestration, export, and destruction. Each pathogen has a different array of CAMP-resistant mechanisms, with invasive disease potential reflecting the utilization of several mechanisms that may act in synergy. Here we discuss recent progress in identifying the sources of CAMP resistance in the medically important Streptococcus genus. Further study of these mechanisms can contribute to our understanding of streptococcal pathogenesis, and may provide new therapeutic targets for therapy and disease prevention. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.
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Affiliation(s)
- Christopher N LaRock
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA; Skaggs School of Medicine and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA; Rady Children's Hospital, San Diego, CA, USA.
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38
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Henningham A, Döhrmann S, Nizet V, Cole JN. Mechanisms of group A Streptococcus resistance to reactive oxygen species. FEMS Microbiol Rev 2015; 39:488-508. [PMID: 25670736 PMCID: PMC4487405 DOI: 10.1093/femsre/fuu009] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 12/19/2014] [Indexed: 12/16/2022] Open
Abstract
Streptococcus pyogenes, also known as group A Streptococcus (GAS), is an exclusively human Gram-positive bacterial pathogen ranked among the ‘top 10’ causes of infection-related deaths worldwide. GAS commonly causes benign and self-limiting epithelial infections (pharyngitis and impetigo), and less frequent severe invasive diseases (bacteremia, toxic shock syndrome and necrotizing fasciitis). Annually, GAS causes 700 million infections, including 1.8 million invasive infections with a mortality rate of 25%. In order to establish an infection, GAS must counteract the oxidative stress conditions generated by the release of reactive oxygen species (ROS) at the infection site by host immune cells such as neutrophils and monocytes. ROS are the highly reactive and toxic byproducts of oxygen metabolism, including hydrogen peroxide (H2O2), superoxide anion (O2•−), hydroxyl radicals (OH•) and singlet oxygen (O2*), which can damage bacterial nucleic acids, proteins and cell membranes. This review summarizes the enzymatic and regulatory mechanisms utilized by GAS to thwart ROS and survive under conditions of oxidative stress. This review discusses the mechanisms utilized by the bacterial pathogen group A Streptococcus to detoxify reactive oxygen species and survive in the human host under conditions of oxidative stress.
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Affiliation(s)
- Anna Henningham
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA The School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia The Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Simon Döhrmann
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Victor Nizet
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA Rady Children's Hospital, San Diego, CA 92123, USA
| | - Jason N Cole
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA The School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD 4072, Australia The Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD 4072, Australia
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39
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The sensor histidine kinase RgfC affects group B streptococcal virulence factor expression independent of its response regulator RgfA. Infect Immun 2015; 83:1078-88. [PMID: 25561709 DOI: 10.1128/iai.02738-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Group B streptococci (GBS; Streptococcus agalactiae) are beta-hemolytic, Gram-positive bacteria that are common asymptomatic colonizers of healthy adults. However, these opportunistic bacteria also cause invasive infections in human newborns and in certain adult populations. To adapt to the various environments encountered during its disease cycle, GBS encodes a number of two-component signaling systems. Previous studies have indicated that the TCS comprising the sensor histidine kinase RgfC and the response regulator RgfA mediate GBS binding to extracellular matrix components, such as fibrinogen. However, in certain GBS clinical isolates, a point mutation in rgfA results in premature truncation of the response regulator. The truncated RgfA protein lacks the C-terminal DNA binding domain necessary for promoter binding and gene regulation. Here, we show that deletion of rgfC in GBS strains lacking a functional RgfA increased systemic infection. Furthermore, infection with the rgfC mutant increased induction of proinflammatory signaling pathways in vivo. Phosphoproteomic analysis revealed that 19 phosphopeptides corresponding to 12 proteins were differentially phosphorylated at aspartate, cysteine, serine, threonine, or tyrosine residues in the rgfC mutant. This included aspartate phosphorylation of a tyrosine kinase, CpsD, and a transcriptional regulator. Consistent with this observation, microarray analysis of the rgfC mutant indicated that >200 genes showed altered expression compared to the isogenic wild-type strain and included transcriptional regulators, transporters, and genes previously associated with GBS pathogenesis. Our observations suggest that in the absence of RgfA, nonspecific RgfC signaling affects the expression of virulence factors and GBS pathogenesis.
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40
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Nawrocki KL, Crispell EK, McBride SM. Antimicrobial Peptide Resistance Mechanisms of Gram-Positive Bacteria. Antibiotics (Basel) 2014; 3:461-92. [PMID: 25419466 PMCID: PMC4239024 DOI: 10.3390/antibiotics3040461] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 09/25/2014] [Accepted: 09/28/2014] [Indexed: 01/09/2023] Open
Abstract
Antimicrobial peptides, or AMPs, play a significant role in many environments as a tool to remove competing organisms. In response, many bacteria have evolved mechanisms to resist these peptides and prevent AMP-mediated killing. The development of AMP resistance mechanisms is driven by direct competition between bacterial species, as well as host and pathogen interactions. Akin to the number of different AMPs found in nature, resistance mechanisms that have evolved are just as varied and may confer broad-range resistance or specific resistance to AMPs. Specific mechanisms of AMP resistance prevent AMP-mediated killing against a single type of AMP, while broad resistance mechanisms often lead to a global change in the bacterial cell surface and protect the bacterium from a large group of AMPs that have similar characteristics. AMP resistance mechanisms can be found in many species of bacteria and can provide a competitive edge against other bacterial species or a host immune response. Gram-positive bacteria are one of the largest AMP producing groups, but characterization of Gram-positive AMP resistance mechanisms lags behind that of Gram-negative species. In this review we present a summary of the AMP resistance mechanisms that have been identified and characterized in Gram-positive bacteria. Understanding the mechanisms of AMP resistance in Gram-positive species can provide guidelines in developing and applying AMPs as therapeutics, and offer insight into the role of resistance in bacterial pathogenesis.
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Affiliation(s)
- Kathryn L Nawrocki
- Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Rd, Atlanta, GA 30322, USA; (K.L.N.); (E.K.C.)
| | - Emily K Crispell
- Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Rd, Atlanta, GA 30322, USA; (K.L.N.); (E.K.C.)
| | - Shonna M McBride
- Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Rd, Atlanta, GA 30322, USA; (K.L.N.); (E.K.C.)
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41
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Wobser D, Ali L, Grohmann E, Huebner J, Sakinc T. A novel role for D-alanylation of lipoteichoic acid of enterococcus faecalis in urinary tract infection. PLoS One 2014; 9:e107827. [PMID: 25296179 PMCID: PMC4189791 DOI: 10.1371/journal.pone.0107827] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/20/2014] [Indexed: 11/19/2022] Open
Abstract
Background Enterococci are the third most common cause of healthcare-associated infections, which include urinary tract infections, bacteremia and endocarditis. Cell-surface structures such as lipoteichoic acid (LTA) have been poorly examined in E. faecalis, especially with respect to urinary tract infections (UTIs). The dlt operon is responsible for the D-alanylation of LTA and includes the gene dltA, which encodes the D-alanyl carrier protein ligase (Dcl). The involvement of LTA in UTI infection by E. faecalis has not been studied so far. Here, we examined the role of teichoic acid alanylation in the adhesion of enterococci to uroepithelial cells. Results In a mouse model of urinary tract infection, we showed that E. faecalis 12030ΔdltA mutant colonizes uroepithelial surfaces more efficiently than wild type bacteria. We also demonstrated that this mutant adhered four fold better to human bladder carcinoma cell line T24 compared to the wild type strain. Bacterial adherence could be significantly inhibited by purified lipoteichoic acid (LTA) and inhibition was specific. Conclusion In contrast to bacteraemia model and adherence to colon surfaces, E. faecalis 12030ΔdltA mutant colonized uroepithelial surfaces more efficiently than wild-type bacteria. In the case of the uroepithelial surface the adherence to specific host cells could be prevented by purified LTA. Our results therefore suggest a novel function of alanylation of LTA in E. faecalis.
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Affiliation(s)
- Dominique Wobser
- Division of Infectious Diseases, Department of Internal Medicine II, University Hospital Freiburg, Freiburg, Germany
| | - Liaqat Ali
- Division of Infectious Diseases, Department of Internal Medicine II, University Hospital Freiburg, Freiburg, Germany
- Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Elisabeth Grohmann
- Division of Infectious Diseases, Department of Internal Medicine II, University Hospital Freiburg, Freiburg, Germany
- Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Johannes Huebner
- Division of Infectious Diseases, Department of Internal Medicine II, University Hospital Freiburg, Freiburg, Germany
- Division of Pediatric Infectious Diseases, Dr. Von Hauner Children's Hospital, Ludwig Maximilian University Munich, Munich, Germany
| | - Türkan Sakinc
- Division of Infectious Diseases, Department of Internal Medicine II, University Hospital Freiburg, Freiburg, Germany
- * E-mail:
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Okumura CYM, Nizet V. Subterfuge and sabotage: evasion of host innate defenses by invasive gram-positive bacterial pathogens. Annu Rev Microbiol 2014; 68:439-58. [PMID: 25002085 DOI: 10.1146/annurev-micro-092412-155711] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The development of a severe invasive bacterial infection in an otherwise healthy individual is one of the most striking and fascinating aspects of human medicine. A small cadre of gram-positive pathogens of the genera Streptococcus and Staphylococcus stand out for their unique invasive disease potential and sophisticated ability to counteract the multifaceted components of human innate defense. This review illustrates how these leading human disease agents evade host complement deposition and activation, impede phagocyte recruitment and activation, resist the microbicidal activities of host antimicrobial peptides and reactive oxygen species, escape neutrophil extracellular traps, and promote and accelerate phagocyte cell death through the action of pore-forming cytolysins. Understanding the molecular basis of bacterial innate immune resistance can open new avenues for therapeutic intervention geared to disabling specific virulence factors and resensitizing the pathogen to host innate immune clearance.
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Affiliation(s)
- Cheryl Y M Okumura
- Department of Biology, Occidental College, Los Angeles, California 90041;
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Revilla-Guarinos A, Gebhard S, Mascher T, Zúñiga M. Defence against antimicrobial peptides: different strategies inFirmicutes. Environ Microbiol 2014; 16:1225-37. [DOI: 10.1111/1462-2920.12400] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/10/2014] [Accepted: 01/11/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Ainhoa Revilla-Guarinos
- Departamento de Biotecnología; Instituto de Agroquímica y Tecnología de Alimentos (IATA); Consejo Superior de Investigaciones Científicas (CSIC); Paterna Valencia Spain
| | - Susanne Gebhard
- Department Biologie I, Mikrobiologie; Ludwig-Maximilians-Universität München; Planegg-Martinsried Germany
| | - Thorsten Mascher
- Department Biologie I, Mikrobiologie; Ludwig-Maximilians-Universität München; Planegg-Martinsried Germany
| | - Manuel Zúñiga
- Departamento de Biotecnología; Instituto de Agroquímica y Tecnología de Alimentos (IATA); Consejo Superior de Investigaciones Científicas (CSIC); Paterna Valencia Spain
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Guo CM, Chen RR, Kalhoro DH, Wang ZF, Liu GJ, Lu CP, Liu YJ. Identification of genes preferentially expressed by highly virulent piscine Streptococcus agalactiae upon interaction with macrophages. PLoS One 2014; 9:e87980. [PMID: 24498419 PMCID: PMC3912197 DOI: 10.1371/journal.pone.0087980] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 12/31/2013] [Indexed: 11/19/2022] Open
Abstract
Streptococcus agalactiae, long recognized as a mammalian pathogen, is an emerging concern with regard to fish. In this study, we used a mouse model and in vitro cell infection to evaluate the pathogenetic characteristics of S. agalactiae GD201008-001, isolated from tilapia in China. This bacterium was found to be highly virulent and capable of inducing brain damage by migrating into the brain by crossing the blood–brain barrier (BBB). The phagocytosis assays indicated that this bacterium could be internalized by murine macrophages and survive intracellularly for more than 24 h, inducing injury to macrophages. Further, selective capture of transcribed sequences (SCOTS) was used to investigate microbial gene expression associated with intracellular survival. This positive cDNA selection technique identified 60 distinct genes that could be characterized into 6 functional categories. More than 50% of the differentially expressed genes were involved in metabolic adaptation. Some genes have previously been described as associated with virulence in other bacteria, and four showed no significant similarities to any other previously described genes. This study constitutes the first step in further gene expression analyses that will lead to a better understanding of the molecular mechanisms used by S. agalactiae to survive in macrophages and to cross the BBB.
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Affiliation(s)
- Chang-Ming Guo
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Rong-Rong Chen
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | | | - Zhao-Fei Wang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Guang-Jin Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Cheng-Ping Lu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yong-Jie Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- * E-mail:
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45
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Tavares LS, Silva CSF, de Souza VC, da Silva VL, Diniz CG, Santos MO. Strategies and molecular tools to fight antimicrobial resistance: resistome, transcriptome, and antimicrobial peptides. Front Microbiol 2013; 4:412. [PMID: 24427156 PMCID: PMC3876575 DOI: 10.3389/fmicb.2013.00412] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 12/15/2013] [Indexed: 11/13/2022] Open
Abstract
The increasing number of antibiotic resistant bacteria motivates prospective research toward discovery of new antimicrobial active substances. There are, however, controversies concerning the cost-effectiveness of such research with regards to the description of new substances with novel cellular interactions, or description of new uses of existing substances to overcome resistance. Although examination of bacteria isolated from remote locations with limited exposure to humans has revealed an absence of antibiotic resistance genes, it is accepted that these genes were both abundant and diverse in ancient living organisms, as detected in DNA recovered from Pleistocene deposits (30,000 years ago). Indeed, even before the first clinical use of antibiotics more than 60 years ago, resistant organisms had been isolated. Bacteria can exhibit different strategies for resistance against antibiotics. New genetic information may lead to the modification of protein structure affecting the antibiotic carriage into the cell, enzymatic inactivation of drugs, or even modification of cellular structure interfering in the drug-bacteria interaction. There are still plenty of new genes out there in the environment that can be appropriated by putative pathogenic bacteria to resist antimicrobial agents. On the other hand, there are several natural compounds with antibiotic activity that may be used to oppose them. Antimicrobial peptides (AMPs) are molecules which are wide-spread in all forms of life, from multi-cellular organisms to bacterial cells used to interfere with microbial growth. Several AMPs have been shown to be effective against multi-drug resistant bacteria and have low propensity to resistance development, probably due to their unique mode of action, different from well-known antimicrobial drugs. These substances may interact in different ways with bacterial cell membrane, protein synthesis, protein modulation, and protein folding. The analysis of bacterial transcriptome may contribute to the understanding of microbial strategies under different environmental stresses and allows the understanding of their interaction with novel AMPs.
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Affiliation(s)
| | - Carolina S. F. Silva
- Department of Microbiology, Immunology and Infectious Diseases, University of Juiz de ForaJuiz de Fora, Brazil
| | | | - Vânia L. da Silva
- Department of Microbiology, Immunology and Infectious Diseases, University of Juiz de ForaJuiz de Fora, Brazil
| | - Cláudio G. Diniz
- Department of Microbiology, Immunology and Infectious Diseases, University of Juiz de ForaJuiz de Fora, Brazil
| | - Marcelo O. Santos
- Department of Biology, University of Juiz de ForaJuiz de Fora, Brazil
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Reichmann NT, Cassona CP, Gründling A. Revised mechanism of D-alanine incorporation into cell wall polymers in Gram-positive bacteria. MICROBIOLOGY-SGM 2013; 159:1868-1877. [PMID: 23858088 PMCID: PMC3783018 DOI: 10.1099/mic.0.069898-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Teichoic acids (TAs) are important for growth, biofilm formation, adhesion and virulence of Gram-positive bacterial pathogens. The chemical structures of the TAs vary between bacteria, though they typically consist of zwitterionic polymers that are anchored to either the peptidoglycan layer as in the case of wall teichoic acid (WTA) or the cell membrane and named lipoteichoic acid (LTA). The polymers are modified with D-alanines and a lack of this decoration leads to increased susceptibility to cationic antimicrobial peptides. Four proteins, DltA-D, are essential for the incorporation of d-alanines into cell wall polymers and it has been established that DltA transfers D-alanines in the cytoplasm of the cell onto the carrier protein DltC. However, two conflicting models have been proposed for the remainder of the mechanism. Using a cellular protein localization and membrane topology analysis, we show here that DltC does not traverse the membrane and that DltD is anchored to the outside of the cell. These data are in agreement with the originally proposed model for D-alanine incorporation through a process that has been proposed to proceed via a D-alanine undecaprenyl phosphate membrane intermediate. Furthermore, we found that WTA isolated from a Staphylococcus aureus strain lacking LTA contains only a small amount of D-alanine, indicating that LTA has a role, either direct or indirect, in the efficient D-alanine incorporation into WTA in living cells.
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Affiliation(s)
- Nathalie T Reichmann
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Carolina Picarra Cassona
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Angelika Gründling
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
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47
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Derré-Bobillot A, Cortes-Perez NG, Yamamoto Y, Kharrat P, Couvé E, Da Cunha V, Decker P, Boissier MC, Escartin F, Cesselin B, Langella P, Bermúdez-Humarán LG, Gaudu P. Nuclease A (Gbs0661), an extracellular nuclease of Streptococcus agalactiae, attacks the neutrophil extracellular traps and is needed for full virulence. Mol Microbiol 2013; 89:518-31. [PMID: 23772975 DOI: 10.1111/mmi.12295] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2013] [Indexed: 12/30/2022]
Abstract
Most bacteria of the genus Streptococcus are opportunistic pathogens, and some of them produce extracellular DNases, which may be important for virulence. Genome analyses of Streptococcus agalactiae (GBS) neonate isolate NEM316 revealed the presence of seven genes putatively encoding secreted DNases, although their functions, if any, are unknown. In this study, we observed that respiration growth of GBS led to the extracellular accumulation of a putative nuclease, identified as being encoded by the gbs0661 gene. When overproduced in Lactococcus lactis, the protein was found to be a divalent cation-requiring, pH-stable and heat-stable nuclease that we named Nuclease A (NucA). Substitution of the histidine(148) by alanine reduced nuclease activity of the GBS wild-type strain, indicating that NucA is the major nuclease ex vivo. We determined that GBS is able to degrade the DNA matrix comprising the neutrophil extracellular trap (NET). The nucA(H148A) mutant was impaired for this function, implicating NucA in the virulence of GBS. In vivo infection studies confirmed that NucA is required for full infection, as the mutant strain allowed increased bacterial clearance from lung tissue and decreased mortality in infected mice. These results show that NucA is involved in NET escape and is needed for full virulence.
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48
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Klinzing DC, Ishmael N, Hotopp JCD, Tettelin H, Shields KR, Madoff LC, Puopolo KM. The two-component response regulator LiaR regulates cell wall stress responses, pili expression and virulence in group B Streptococcus. MICROBIOLOGY-SGM 2013; 159:1521-1534. [PMID: 23704792 DOI: 10.1099/mic.0.064444-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Group B Streptococcus (GBS) remains the leading cause of early onset sepsis among term infants. Evasion of innate immune defences is critical to neonatal GBS disease pathogenesis. Effectors of innate immunity, as well as numerous antibiotics, frequently target the peptidoglycan layer of the Gram-positive bacterial cell wall. The intramembrane-sensing histidine kinase (IM-HK) class of two-component regulatory systems has been identified as important to the Gram-positive response to cell wall stress. We have characterized the GBS homologue of LiaR, the response regulator component of the Lia system, to determine its role in GBS pathogenesis. LiaR is expressed as part of a three-gene operon (liaFSR) with a promoter located upstream of liaF. A LiaR deletion mutant is more susceptible to cell wall-active antibiotics (vancomycin and bacitracin) as well as antimicrobial peptides (polymixin B, colistin, and nisin) compared to isogenic wild-type GBS. LiaR mutant GBS are significantly attenuated in mouse models of both GBS sepsis and pneumonia. Transcriptional profiling with DNA microarray and Northern blot demonstrated that LiaR regulates expression of genes involved in microbial defence against host antimicrobial systems including genes functioning in cell wall synthesis, pili formation and cell membrane modification. We conclude that the LiaFSR system, the first member of the IM-HK regulatory systems to be studied in GBS, is involved in sensing perturbations in the integrity of the cell wall and activates a transcriptional response that is important to the pathogenesis of GBS infection.
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Affiliation(s)
- David C Klinzing
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.,Channing Laboratory, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA
| | - Nadeeza Ishmael
- Institute for Genome Sciences, University of Maryland Baltimore, 801 West Baltimore Street, Baltimore, MD 21201, USA.,The J. Craig Venter Institute, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Julie C Dunning Hotopp
- Institute for Genome Sciences, University of Maryland Baltimore, 801 West Baltimore Street, Baltimore, MD 21201, USA.,The J. Craig Venter Institute, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Hervé Tettelin
- Institute for Genome Sciences, University of Maryland Baltimore, 801 West Baltimore Street, Baltimore, MD 21201, USA.,The J. Craig Venter Institute, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Kelly R Shields
- Channing Laboratory, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA
| | - Lawrence C Madoff
- Massachusetts Department of Public Health, Jamaica Plain, MA 02130, USA.,Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, 55 Lake Avenue, North Worcester, MA 01655, USA
| | - Karen M Puopolo
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.,Department of Newborn Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.,Channing Laboratory, Brigham and Women's Hospital, 181 Longwood Avenue, Boston, MA 02115, USA
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Gnanadhas DP, Marathe SA, Chakravortty D. Biocides--resistance, cross-resistance mechanisms and assessment. Expert Opin Investig Drugs 2012; 22:191-206. [PMID: 23215733 DOI: 10.1517/13543784.2013.748035] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Antibiotic resistance in bacterial pathogens has increased worldwide leading to treatment failures. Concerns have been raised about the use of biocides as a contributing factor to the risk of antimicrobial resistance (AMR) development. In vitro studies demonstrating increase in resistance have often been cited as evidence for increased risks. It is therefore important to understand the mechanisms of resistance employed by bacteria toward biocides used in consumer products and their potential to impart cross-resistance to therapeutic antibiotics. AREAS COVERED In this review, the mechanisms of resistance and cross-resistance reported in the literature toward biocides commonly used in consumer products are summarized. The physiological and molecular techniques used in describing and examining these mechanisms are reviewed and application of these techniques for systematic assessment of biocides for their potential to develop resistance and/or cross-resistance is discussed. EXPERT OPINION The guidelines in the usage of biocides in household or industrial purpose should be monitored and regulated to avoid the emergence of any MDR strains. The genetic and molecular methods to monitor the resistance development to biocides should be developed and included in preclinical and clinical studies.
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Affiliation(s)
- Divya Prakash Gnanadhas
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research and Biosafety Laboratories, Indian Institute of Science, Bangalore 560012, India
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50
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McQuade R, Roxas B, Viswanathan V, Vedantam G. Clostridium difficile clinical isolates exhibit variable susceptibility and proteome alterations upon exposure to mammalian cationic antimicrobial peptides. Anaerobe 2012; 18:614-20. [DOI: 10.1016/j.anaerobe.2012.09.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 09/06/2012] [Accepted: 09/12/2012] [Indexed: 01/04/2023]
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