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Hupp S, Grandgirard D, Mitchell TJ, Leib SL, Hathaway LJ, Iliev AI. Pneumolysin and the bacterial capsule of Streptococcus pneumoniae cooperatively inhibit taxis and motility of microglia. J Neuroinflammation 2019; 16:105. [PMID: 31103037 PMCID: PMC6525981 DOI: 10.1186/s12974-019-1491-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/30/2019] [Indexed: 01/11/2023] Open
Abstract
Background Streptococcus pneumoniae is the cause of a highly lethal form of meningitis in humans. Microglial cells in the brain represent the first line of defense against pathogens, and they participate in the inflammatory response. The cholesterol-dependent cytolysin pneumolysin and the bacterial capsule are key pathogenic factors, known to exacerbate the course of pneumococcal meningitis. Methods We utilized live imaging and immunostaining of glial cells in dissociated and acute brain slice cultures to study the effect of pneumococcal factors, including the cholesterol-dependent cytolysin pneumolysin and the pneumococcal capsule, on microglial motility and taxis. Results In brain tissue, primary microglia cells showed an enhanced response towards lysates from bacteria lacking capsules and pneumolysin as they moved rapidly to areas with an abundance of bacterial factors. The presence of bacterial capsules and pneumolysin cumulatively inhibited microglial taxis. In mixed cultures of astrocytes and microglia, the motility of microglia was inhibited by capsular components within minutes after exposure. The reduced motility was partially reversed by mannan, a mannose receptor inhibitor. The effects on microglia were not mediated by astrocytes because pure microglial cells responded to various pneumococcal lysates similarly with distinct cell shape changes as seen in mixed cultures. Conclusions Our data indicate that microglia possess the capacity for a very agile response towards bacterial pathogens, but key pathogenic factors, such as pneumococcal capsules and pneumolysin, inhibited this response shortly after a bacterial challenge. Furthermore, we demonstrate for the first time that the bacterial capsule affects cellular behaviors such as motility and taxis. Electronic supplementary material The online version of this article (10.1186/s12974-019-1491-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sabrina Hupp
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland
| | - Denis Grandgirard
- Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3010, Bern, Switzerland
| | - Timothy J Mitchell
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, Biosciences Building, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Stephen L Leib
- Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3010, Bern, Switzerland
| | - Lucy J Hathaway
- Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3010, Bern, Switzerland
| | - Asparouh I Iliev
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012, Bern, Switzerland.
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Thorsdottir S, Henriques-Normark B, Iovino F. The Role of Microglia in Bacterial Meningitis: Inflammatory Response, Experimental Models and New Neuroprotective Therapeutic Strategies. Front Microbiol 2019; 10:576. [PMID: 30967852 PMCID: PMC6442515 DOI: 10.3389/fmicb.2019.00576] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/06/2019] [Indexed: 12/11/2022] Open
Abstract
Microglia have a pivotal role in the pathophysiology of bacterial meningitis. The goal of this review is to provide an overview on how microglia respond to bacterial pathogens targeting the brain, how the interplay between microglia and bacteria can be studied experimentally, and possible ways to use gained knowledge to identify novel preventive and therapeutic strategies. We discuss the dual role of microglia in disease development, the beneficial functions crucial for bacterial clearing, and the destructive properties through triggering neuroinflammation, characterized by cytokine and chemokine release which leads to leukocyte trafficking through the brain vascular endothelium and breakdown of the blood-brain barrier integrity. Due to intrinsic complexity of microglia and up until recently lack of specific markers, the study of microglial response to bacterial pathogens is challenging. New experimental models and techniques open up possibilities to accelerate progress in the field. We review existing models and discuss possibilities and limitations. Finally, we summarize recent findings where bacterial virulence factors are identified to be important for the microglial response, and how manipulation of evoked responses could be used for therapeutic or preventive purposes. Among promising approaches are: modulations of microglia phenotype switching toward anti-inflammatory and phagocytic functions, the use of non-bacterolytic antimicrobials, preventing release of bacterial components into the neural milieu and consequential amplification of immune activation, and protection of the blood-brain barrier integrity.
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Affiliation(s)
- Sigrun Thorsdottir
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Bioclinicum, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Bioclinicum, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,Singapore Centre for Environmental Life Sciences Engineering (SCELSE) and Lee Kong Chian School of Medicine (LKC), Nanyang Technological University (NTU), Singapore, Singapore
| | - Federico Iovino
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Bioclinicum, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
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3
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Contribution of Pili of S. Pneumoniae in the Onset of Meningitis. FOLIA VETERINARIA 2018. [DOI: 10.2478/fv-2018-0010] [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
Abstract
Bacterial meningitis is a devastating worldwide disease. Half of the survivors of meningitis remain with permanent neurological sequelae. The pathogenesis of meningitis is based on a complex host-pathogen interaction. Streptococcus pneumoniae is a life-threatening neuroinvasive pathogen that asymptomatically colonizes the upper respiratory tract. Adherence of pneumococci to the host epithelium is a prerequisite in the onset of streptococcal infections; such adherence is favored by the formation of bacterial pili. In this article, we will describe the pneumococcal pili and its contribution to the onset of meningitis.
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Jiménez-Munguía I, Pulzova L, Kanova E, Tomeckova Z, Majerova P, Bhide K, Comor L, Sirochmanova I, Kovac A, Bhide M. Proteomic and bioinformatic pipeline to screen the ligands of S. pneumoniae interacting with human brain microvascular endothelial cells. Sci Rep 2018; 8:5231. [PMID: 29588455 PMCID: PMC5869694 DOI: 10.1038/s41598-018-23485-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 03/14/2018] [Indexed: 01/17/2023] Open
Abstract
The mechanisms by which Streptococcus pneumoniae penetrates the blood-brain barrier (BBB), reach the CNS and causes meningitis are not fully understood. Adhesion of bacterial cells on the brain microvascular endothelial cells (BMECs), mediated through protein-protein interactions, is one of the crucial steps in translocation of bacteria across BBB. In this work, we proposed a systematic workflow for identification of cell wall associated ligands of pneumococcus that might adhere to the human BMECs. The proteome of S. pneumoniae was biotinylated and incubated with BMECs. Interacting proteins were recovered by affinity purification and identified by data independent acquisition (DIA). A total of 44 proteins were identified from which 22 were found to be surface-exposed. Based on the subcellular location, ontology, protein interactive analysis and literature review, five ligands (adhesion lipoprotein, endo-β-N-acetylglucosaminidase, PhtA and two hypothetical proteins, Spr0777 and Spr1730) were selected to validate experimentally (ELISA and immunocytochemistry) the ligand-BMECs interaction. In this study, we proposed a high-throughput approach to generate a dataset of plausible bacterial ligands followed by systematic bioinformatics pipeline to categorize the protein candidates for experimental validation. The approach proposed here could contribute in the fast and reliable screening of ligands that interact with host cells.
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Affiliation(s)
- Irene Jiménez-Munguía
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovak Republic
| | - Lucia Pulzova
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovak Republic
| | - Evelina Kanova
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovak Republic
| | - Zuzana Tomeckova
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovak Republic
| | - Petra Majerova
- Institute of Neuroimmunology of Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Katarina Bhide
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovak Republic
| | - Lubos Comor
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovak Republic
| | - Ivana Sirochmanova
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovak Republic
| | - Andrej Kovac
- Institute of Neuroimmunology of Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Mangesh Bhide
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Kosice, Kosice, Slovak Republic.
- Institute of Neuroimmunology of Slovak Academy of Sciences, Bratislava, Slovak Republic.
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John J, Kasudhan KS, Kanungo R, Sharma S, Dohe V, Prashanth K. Distribution of different genes responsible for invasive characteristics, detection of point mutations in capsular gene wchA and biofilm production among the invasive and non-invasive isolates of Streptococcus pneumoniae. Indian J Med Microbiol 2018; 35:511-517. [PMID: 29405142 DOI: 10.4103/ijmm.ijmm_17_183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Streptococcus pneumoniae continues to cause morbidity and mortality across the globe, with developing countries bearing the brunt of the disease. It is mainly responsible for meningitis, pneumonia and septicaemia primarily in children, elderly and immunocompromised persons. Colonisation and persistence in the human nasopharynx occur during early childhood, and it appears to be prerequisite for invasive pneumococcal disease (IPD). Factors that help in persistent colonisation and subsequent invasion are ill understood. Several virulence factors have been incriminated for nasopharyngeal carriage (NC) as well as for the manifestation of the pathogenesis of IPD. MATERIALS AND METHODS This study attempts to characterise the S. pneumoniae isolates through analysing the distribution of different virulence markers such as lytA, ply, pbpA, eno, psaA, amiA, ciaR and wchA among the isolates obtained from disease and NC. A total of 37 isolates which include 14 invasive and 23 non-invasive isolates were investigated by polymerase chain reaction to detect the genes. Eight representative isolates were investigated for mutations in wchA by DNA sequencing that may responsible for capsular variation. RESULTS Ply, pbpA, amiA and eno were observed in a greater percentage of invasive isolates than non-invasive isolates though these differences are not statistically significant. Other two genes ciaH and psaA did not show any significant difference between two groups of isolates. Biofilm production was significantly higher in than non-invasive isolates when compared to invasive isolates. Sequence analysis of wchA revealed three significant point mutations or single-nucleotide polymorphisms (SNPs) among the isolates of one particular cluster (cluster III). These SNPs are responsible for a non-synonymous mutation in wchA bringing in an amino acid change in WchA protein, which is a part of the capsule of S. pneumoniae. Notably, all the three isolates present in cluster III had these SNPs and all of them were isolated from ocular infections. CONCLUSION The results of our study implies a possible capsular variations among the isolates and this may have an impact on capsular typing.
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Affiliation(s)
- James John
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Kripa Shanker Kasudhan
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry; Department of Pharmacology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Reba Kanungo
- Department of Microbiology, Pondicherry Institute of Medical Sciences, Puducherry, India
| | - Savitri Sharma
- Jhaveri Microbiology Centre, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Vaishali Dohe
- Department of Microbiology, Byramjee Jeejeebhoy Government Medical College, Pune, Maharashtra, India
| | - K Prashanth
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Puducherry, India
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Rahman NA, Sharudin A, Diah S, Muharram SH. Serotyping of Brunei pneumococcal clinical strains and the investigation of their capability to adhere and invade a brain endothelium model. Microb Pathog 2017; 110:352-358. [PMID: 28711510 DOI: 10.1016/j.micpath.2017.07.021] [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: 01/03/2017] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Pneumococcal infections have caused morbidity and mortality globally. Streptococcus pneumoniae (pneumococci) are commensal bacteria that colonize the nasopharynx, asymptomatically. From there, pneumococci can spread in the lungs causing pneumonia and disseminate in the bloodstream causing bacteremia (sepsis) and reach the brain leading to meningitis. Endothelial cells are one of the most important components of the blood-brain barrier that separates the blood from the brain and plays the first protective role against pneumococcal entry. Thus this study aimed to investigate on the ability of non-meningitis pneumococcal clinical strains to adhere and invade a brain endothelium model. METHODS Two pneumococcal Brunei clinical strains were serotyped by multiplex PCR method using oligonucleotide sequences derived from Centers for Disease Control and Prevention. A validated immortalised mouse brain endothelial cell line (bEnd.3) was used as a brain endothelium model for the study of the pneumococcal breach of the blood-brain barrier using an adherence and invasion assay. RESULTS Both of the pneumococcal clinical strains were found to be serotype 19F, a common circulating serotype in Southeast Asia and globally and possess the ability to adhere and invade the brain endothelial cells. CONCLUSION In addition, this is the first report on the serotype identification of pneumococci in Brunei Darussalam and their application on a brain endothelium model. Further studies are required to understand the virulence capabilities of the clinical strains.
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Affiliation(s)
- Nurul Adhwa Rahman
- Pengiran Anak Puteri Rashidah Sa'adatul Bolkiah Institute of Health Sciences, Universiti Brunei Darussalam, Brunei Darussalam.
| | - Aishah Sharudin
- School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Suwarni Diah
- Pengiran Anak Puteri Rashidah Sa'adatul Bolkiah Institute of Health Sciences, Universiti Brunei Darussalam, Brunei Darussalam
| | - Siti Hanna Muharram
- Pengiran Anak Puteri Rashidah Sa'adatul Bolkiah Institute of Health Sciences, Universiti Brunei Darussalam, Brunei Darussalam
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TIGR4 strain causes more severe disease than WU2 strain in a mouse model of Streptococcus pneumoniae meningitis: a common pathogenic role for interferon-γ. Microbes Infect 2017; 19:413-421. [PMID: 28438705 DOI: 10.1016/j.micinf.2017.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 04/05/2017] [Accepted: 04/05/2017] [Indexed: 01/08/2023]
Abstract
Streptococcus pneumoniae (S. pneumoniae) meningitis causes debilitating neurological symptoms and acute fatalities in patients, and long-term neurological sequelae in some survivors. Current vaccines do not protect against all 94 known S. pneumoniae capsular serotypes, many of which are capable of causing pneumococcal meningitis (PM). We here compare the pathogenic outcomes of two clinically virulent isolates of S. pneumoniae, serotype 3 strain WU2 and serotype 4 strain TIGR4, in a murine model of PM. At an identical infectious dosage of 103 CFU administered via the intracerebroventricular route, significantly greater mortality, interleukin (IL)1β and IL6 production, and blood-brain barrier dysfunction occurred in TIGR4-induced PM compared to PM caused by WU2. Higher bacterial counts in the cerebrospinal fluid and nitrite/nitrate in serum were observed 40 h post inoculation with TIGR4 compared to mice infected with WU2. Similar to our previous findings in WU2 PM, interferon-γ was an essential driver of the pathogenesis of TIGR4 PM, suggesting that this cytokine may be a common pathogenic agent across a range of pneumococcal meningitides and, thus, a potential therapeutic target for intervention.
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8
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Gholamhosseini-Moghaddam T, Rad M, Mousavi SF, Ghazvini K. Detection of lytA, pspC, and rrgA genes in Streptococcus pneumoniae isolated from healthy children. IRANIAN JOURNAL OF MICROBIOLOGY 2015; 7:156-60. [PMID: 26668703 PMCID: PMC4676985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND AND OBJECTIVES Many surface proteins are implicated in nasopharyngeal colonization and pathogenesis of Streptococcus pneumoniae. Some of these factors are candidate antigens for protein based vaccines. New vaccine designs focus on the surface proteins (e. g., pspA and pspC) and also cytolysin, and pneumolysin. In this study, 3 key virulence genes, lytA, pspC, and rrgA, which encoded surface proteins, were detected among S. pneumoniae isolates. MATERIALS AND METHODS A total of 260 nasopharyngeal swabs were collected from healthy children under 6 years old attending day care centers in Mashhad, Iran. Isolates of S. pneumoniae were confirmed by optochin susceptibility and colony appearance and also by PCR for cpsA gene. The presence of lytA, pspC, and rrgA genes were also detected by PCR. RESULTS A total of 59 isolates were confirmed as S. pneumoniae. Among these isolates, 50 (84.74%), 19 (32.20%), and 2 (3.38%) were positive for lytA, rrgA, and pspC genes respectively. The presence of these genes among S.pneumoniae isolates were as follows: 1) rrgA, lytA, pspC (1 isolate), 2) rrgA, lytA(17isolates), 3) pspC (2 isolate), 4) lytA (50 isolates). CONCLUSION cpsA gene was specific for detection of S. pneumoniae isolates which were colonized in nasopharynx. The lytA gene was the most frequent gene among the S. pneumoniae isolates, and combination of rrgA, lytA was the most observed pattern. Thus, it is important for future monitoring of vaccine formulation in our country.
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Affiliation(s)
| | - Mehrnaz Rad
- Department of Pathobiology, School of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Seyed Fazlollah Mousavi
- Department of Bacteriology and Microbiology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Kiarash Ghazvini
- Antimicrobial Resistance Research Center, Faculty of Madicine, Mashhad University of Medical Sciences, Mashhad, Iran
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Hu DK, Liu Y, Li XY, Qu Y. In vitro expression of Streptococcus pneumoniae ply gene in human monocytes and pneumocytes. Eur J Med Res 2015; 20:52. [PMID: 25943628 PMCID: PMC4426643 DOI: 10.1186/s40001-015-0142-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/27/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Streptococcus pneumoniae is one major cause of pneumonia in human and contains various virulence factors that contribute to pathogenesis of pneumococcal disease. This study investigated the role of pneumolysin, Ply, in facilitating S. pneumoniae invasion into the host blood stream. METHODS S. pneumoniae strains were isolated from clinical blood and sputum samples and confirmed by PCR. Expression of ply gene was assessed by infecting human monocytes and pneumocytes. RESULTS A total of 23 strains of S. pneumoniae isolated from blood (n = 11) and sputum (n = 12) along with S. pneumoniae ATCC49619 were used to infect human monocyte (THP-1) and Type II pneumocyte (A549) cell lines. All clinical strains of S. pneumoniae showed higher expression of ply mRNA than the American Type Culture Collection (ATCC) strain. Among the clinical strains, blood isolates showed higher expression of ply genes than sputum isolates, i.e., 2(1.5)- to 2(1.6)-folds in THP-1 and 2(0.4)- to 2(4.9)-folds in A549 cell lines. CONCLUSIONS The data from the current study demonstrated that ply gene of blood- and sputum-derived S. pneumoniae is differentially expressed in two different cell lines. Under survival pressure, ply is highly expressed in these two cell lines for blood-derived S. pneumoniae, indicating that ply gene may facilitate S. pneumoniae invasion into the host blood system.
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Affiliation(s)
- Da-Kang Hu
- Department of Laboratory Medicine, Taizhou Municipal Hospital, 381# Zhongshan East Road, Taizhou, 318000, China.
| | - Yang Liu
- Department of Laboratory Medicine, The First Affiliated Hospital of Nanchang University, 17# Yong Wai Zheng Street, Nanchang, 330006, China.
| | - Xiang-Yang Li
- Department of Laboratory Medicine, The Second Affiliated Hospital of Wenzhou Medical University, 109# College West Road, Wenzhou, 325027, China.
| | - Ying Qu
- Department of Laboratory Medicine, Taizhou Municipal Hospital, 381# Zhongshan East Road, Taizhou, 318000, China.
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10
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León M, Bastías R. Virulence reduction in bacteriophage resistant bacteria. Front Microbiol 2015; 6:343. [PMID: 25954266 PMCID: PMC4407575 DOI: 10.3389/fmicb.2015.00343] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/07/2015] [Indexed: 01/21/2023] Open
Abstract
Bacteriophages can influence the abundance, diversity, and evolution of bacterial communities. Several bacteriophages have been reported to add virulence factors to their host and to increase bacterial virulence. However, lytic bacteriophages can also exert a selective pressure allowing the proliferation of strains with reduced virulence. This reduction can be explained because bacteriophages use structures present on the bacterial surface as receptors, which can be virulence factors in different bacterial species. Therefore, strains with modifications in these receptors will be resistant to bacteriophage infection and may also exhibit reduced virulence. This mini-review summarizes the reports on bacteriophage-resistant strains with reductions in virulence, and it discusses the potential consequences in phage therapy and in the use of bacteriophages to select attenuated strains for vaccines.
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Affiliation(s)
- Marcela León
- Laboratory of Microbiology, Institute of Biology, Pontificia Universidad Católica de Valparaíso Valparaíso, Chile
| | - Roberto Bastías
- Laboratory of Microbiology, Institute of Biology, Pontificia Universidad Católica de Valparaíso Valparaíso, Chile
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Zeng XF, Ma Y, Yang L, Zhou L, Xin Y, Chang L, Zhang JR, Hao X. A C-terminal truncated mutation of licC attenuates the virulence of Streptococcus pneumoniae. Res Microbiol 2014; 165:630-8. [PMID: 25283725 DOI: 10.1016/j.resmic.2014.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/21/2014] [Accepted: 09/11/2014] [Indexed: 10/24/2022]
Abstract
LicC has been identified as a virulence factor of Streptococcus pneumoniae. However, its role in virulence is still not fully understood because deletion of licC is lethal for the bacterium. In this study, a mutant with 78-bp truncation at the C-terminus of licC was obtained from a signature-tagged mutagenesis (STM) library. The mutant was viable with a large reduction in enzymatic activity as CTP:phosphocholine cytidylyltransferase detected in vitro using a firefly luciferase assay. The mutation attenuated the adhesion and invasion of S. pneumoniae ST556 (serotype 19F) to epithelial cells by 72% and 80%, respectively, and increased the phagocytosis by macrophages for 16.5%, compared to the parental strain. When the mutation was introduced into the encapsulated D39 strain (serotype 2), it led to attenuated virulence in mouse models either by intranasal colonization or by intraperitoneal infection. In addition, the phosphocholine (PCho) on cell surface was decreased, and the choline binding proteins (CBPs) were impaired, which may explain the attenuated virulence of the mutant. These observations indicate that C-terminus of licC is accounted for the main activity of LicC in PCho metabolism and is essential for the virulence of S. pneumoniae, which provides a novel target for drug design against pneumococcal infection.
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Affiliation(s)
- Xian-Fei Zeng
- Department of Clinical Laboratory Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
| | - Yueyun Ma
- Department of Clinical Laboratory Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
| | - Liu Yang
- Department of Clinical Laboratory Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
| | - Lei Zhou
- Department of Clinical Laboratory Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
| | - Yijuan Xin
- Department of Clinical Laboratory Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
| | - Liang Chang
- Department of Clinical Laboratory Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing 100017, China.
| | - Xiaoke Hao
- Department of Clinical Laboratory Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
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