1
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Alreja AB, Linden SB, Lee HR, Chao KL, Herzberg O, Nelson DC. Understanding the Molecular Basis for Homodimer Formation of the Pneumococcal Endolysin Cpl-1. ACS Infect Dis 2023; 9:1092-1104. [PMID: 37126660 PMCID: PMC10577085 DOI: 10.1021/acsinfecdis.2c00627] [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] [Indexed: 05/03/2023]
Abstract
The rise of multi-drug-resistant bacteria that cannot be treated with traditional antibiotics has prompted the search for alternatives to combat bacterial infections. Endolysins, which are bacteriophage-derived peptidoglycan hydrolases, are attractive tools in this fight. Several studies have already demonstrated the efficacy of endolysins in targeting bacterial infections. Endolysins encoded by bacteriophages that infect Gram-positive bacteria typically possess an N-terminal catalytic domain and a C-terminal cell-wall binding domain (CWBD). In this study, we have uncovered the molecular mechanisms that underlie formation of a homodimer of Cpl-1, an endolysin that targets Streptococcus pneumoniae. Here, we use site-directed mutagenesis, analytical size exclusion chromatography, and analytical ultracentrifugation to disprove a previous suggestion that three residues at the N-terminus of the CWBD are involved in the formation of a Cpl-1 dimer in the presence of choline in solution. We conclusively show that the C-terminal tail region of Cpl-1 is involved in formation of the dimer. Alanine scanning mutagenesis generated various tail mutant constructs that allowed identification of key residues that mediate Cpl-1 dimer formation. Finally, our results allowed identification of a consensus sequence (FxxEPDGLIT) required for choline-dependent dimer formation─a sequence that occurs frequently in pneumococcal autolysins and endolysins. These findings shed light on the mechanisms of Cpl-1 and related enzymes and can be used to inform future engineering efforts for their therapeutic development against S. pneumoniae.
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Affiliation(s)
- Adit B Alreja
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
- Biological Sciences Graduate Program - Molecular and Cellular Biology Concentration, University of Maryland, College Park, Maryland 20742, USA
| | - Sara B Linden
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
| | - Harrison R Lee
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
| | - Kinlin L Chao
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
| | - Osnat Herzberg
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
- Department of Biochemistry and Chemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Daniel C Nelson
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, USA
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
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2
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Korkmaz FT, Traber KE. Innate immune responses in pneumonia. Pneumonia (Nathan) 2023; 15:4. [PMID: 36829255 PMCID: PMC9957695 DOI: 10.1186/s41479-023-00106-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 01/05/2023] [Indexed: 02/26/2023] Open
Abstract
The lungs are an immunologically unique environment; they are exposed to innumerable pathogens and particulate matter daily. Appropriate clearance of pathogens and response to pollutants is required to prevent overwhelming infection, while preventing tissue damage and maintaining efficient gas exchange. Broadly, the innate immune system is the collection of immediate, intrinsic immune responses to pathogen or tissue injury. In this review, we will examine the innate immune responses of the lung, with a particular focus on their role in pneumonia. We will discuss the anatomic barriers and antimicrobial proteins of the lung, pathogen and injury recognition, and the role of leukocytes (macrophages, neutrophils, and innate lymphocytes) and lung stromal cells in innate immunity. Throughout the review, we will focus on new findings in innate immunity as well as features that are unique to the lung.
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Affiliation(s)
- Filiz T Korkmaz
- Department of Medicine, Division of Immunology & Infectious Disease, University of Massachusetts, Worcester, MA, USA
- Pulmonary Center, Boston University School of Medicine, Boston, MA, USA
| | - Katrina E Traber
- Pulmonary Center, Boston University School of Medicine, Boston, MA, USA.
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
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3
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Gupta V, Shekhawat SS, Kulshreshtha NM, Gupta AB. A systematic review on chlorine tolerance among bacteria and standardization of their assessment protocol in wastewater. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 86:261-291. [PMID: 35906907 DOI: 10.2166/wst.2022.206] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Though chlorine is a cost-effective disinfectant for water and wastewaters, the bacteria surviving after chlorination pose serious public health and environmental problems. This review critically assesses the mechanism of chlorine disinfection as described by various researchers; factors affecting chlorination efficacy; and the re-growth potential of microbial contaminations in treated wastewater post chlorination to arrive at meaningful doses for ensuring health safety. Literature analysis shows procedural inconsistencies in the assessment of chlorine tolerant bacteria, making it extremely difficult to compare the tolerance characteristics of different reported tolerant bacteria. A comparison of logarithmic reduction after chlorination and the concentration-time values for prominent pathogens led to the generation of a standard protocol for the assessment of chlorine tolerance. The factors that need to be critically monitored include applied chlorine doses, contact time, determination of chlorine demands of the medium, and the consideration of bacterial counts immediately after chlorination and in post chlorinated samples (regrowth). The protocol devised here appropriately assesses the chlorine-tolerant bacteria and urges the scientific community to report the regrowth characteristics as well. This would increase the confidence in data interpretation that can provide a better understanding of chlorine tolerance in bacteria and aid in formulating strategies for effective chlorination.
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Affiliation(s)
- Vinayak Gupta
- Alumnus, Department of Civil and Environmental Engineering, National University of Singapore, Singapore; School of Environment and Society, Tokyo Institute of Technology, Tokyo, Japan
| | - Sandeep Singh Shekhawat
- Department of Civil Engineering, Malaviya National Institute of Technology, Jaipur, India E-mail: ; School of Life and Basic Sciences, SIILAS Campus, Jaipur National University Jaipur, India
| | - Niha Mohan Kulshreshtha
- Department of Civil Engineering, Malaviya National Institute of Technology, Jaipur, India E-mail:
| | - Akhilendra Bhushan Gupta
- Department of Civil Engineering, Malaviya National Institute of Technology, Jaipur, India E-mail:
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4
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Simmons SR, Tchalla EYI, Bhalla M, Bou Ghanem EN. The Age-Driven Decline in Neutrophil Function Contributes to the Reduced Efficacy of the Pneumococcal Conjugate Vaccine in Old Hosts. Front Cell Infect Microbiol 2022; 12:849224. [PMID: 35402289 PMCID: PMC8984502 DOI: 10.3389/fcimb.2022.849224] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/28/2022] [Indexed: 01/04/2023] Open
Abstract
Despite the availability of vaccines, Streptococcus pneumoniae (pneumococcus) remains a serious cause of infections in the elderly. The efficacy of anti-pneumococcal vaccines declines with age. While age-driven changes in antibody responses are well defined, less is known about the role of innate immune cells such as polymorphonuclear leukocytes (PMNs) in the reduced vaccine protection seen in aging. Here we explored the role of PMNs in protection against S. pneumoniae in vaccinated hosts. We found that depletion of PMNs in pneumococcal conjugate vaccine (PCV) treated young mice prior to pulmonary challenge with S. pneumoniae resulted in dramatic loss of host protection against infection. Immunization boosted the ability of PMNs to kill S. pneumoniae and this was dependent on bacterial opsonization by antibodies. Bacterial opsonization with immune sera increased several PMN anti-microbial activities including bacterial uptake, degranulation and ROS production. As expected, PCV failed to protect old mice against S. pneumoniae. In probing the role of PMNs in this impaired protection, we found that aging was accompanied by an intrinsic decline in PMN function. PMNs from old mice failed to effectively kill S. pneumoniae even when the bacteria were opsonized with immune sera from young controls. In exploring mechanisms, we found that PMNs from old mice produced less of the antimicrobial peptide CRAMP and failed to efficiently kill engulfed pneumococci. Importantly, adoptive transfer of PMNs from young mice reversed the susceptibility of vaccinated old mice to pneumococcal infection. Overall, this study demonstrates that the age-driven decline in PMN function impairs vaccine-mediated protection against Streptococcus pneumoniae.
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5
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de Porto AP, Liu Z, de Beer R, Florquin S, Roelofs JJTH, de Boer OJ, den Haan JMM, Hendriks RW, van 't Veer C, van der Poll T, de Vos AF. Bruton's Tyrosine Kinase-Mediated Signaling in Myeloid Cells Is Required for Protective Innate Immunity During Pneumococcal Pneumonia. Front Immunol 2021; 12:723967. [PMID: 34552589 PMCID: PMC8450579 DOI: 10.3389/fimmu.2021.723967] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/19/2021] [Indexed: 12/20/2022] Open
Abstract
Bruton’s tyrosine kinase (Btk) is a cytoplasmic kinase expressed in B cells and myeloid cells. It is essential for B cell development and natural antibody-mediated host defense against bacteria in humans and mice, but little is known about the role of Btk in innate host defense in vivo. Previous studies have indicated that lack of (natural) antibodies is paramount for impaired host defense against Streptococcus (S.) pneumoniae in patients and mice with a deficiency in functional Btk. In the present study, we re-examined the role of Btk in B cells and myeloid cells during pneumococcal pneumonia and sepsis in mice. The antibacterial defense of Btk-/- mice was severely impaired during pneumococcal pneumosepsis and restoration of natural antibody production in Btk-/- mice by transgenic expression of Btk specifically in B cells did not suffice to protect against infection. Btk-/- mice with reinforced Btk expression in MhcII+ cells, including B cells, dendritic cells and macrophages, showed improved antibacterial defense as compared to Btk-/- mice. Bacterial outgrowth in Lysmcre-Btkfl/Y mice was unaltered despite a reduced capacity of Btk-deficient alveolar macrophages to respond to pneumococci. Mrp8cre-Btkfl/Y mice with a neutrophil specific paucity in Btk expression, however, demonstrated impaired antibacterial defense. Neutrophils of Mrp8cre-Btkfl/Y mice displayed reduced release of granule content after pulmonary installation of lipoteichoic acid, a gram-positive bacterial cell wall component relevant for pneumococci. Moreover, Btk deficient neutrophils showed impaired degranulation and phagocytosis upon incubation with pneumococci ex vivo. Taken together, the results of our study indicate that besides regulating B cell-mediated immunity, Btk is critical for regulation of myeloid cell-mediated, and particularly neutrophil-mediated, innate host defense against S. pneumoniae in vivo.
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Affiliation(s)
- Alexander P de Porto
- Center for Experimental and Molecular Medicine (CEMM), Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Zhe Liu
- Center for Experimental and Molecular Medicine (CEMM), Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Amsterdam Infection and Immunity Institute (AI&II), Amsterdam University Medical Centers (UMC), Amsterdam, Netherlands
| | - Regina de Beer
- Center for Experimental and Molecular Medicine (CEMM), Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Amsterdam Infection and Immunity Institute (AI&II), Amsterdam University Medical Centers (UMC), Amsterdam, Netherlands
| | - Sandrine Florquin
- Department of Pathology, Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Joris J T H Roelofs
- Department of Pathology, Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Onno J de Boer
- Department of Pathology, Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Joke M M den Haan
- Department of Molecular Cell Biology and Immunology, Amsterdam University Medical Centers (UMC), Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Rudi W Hendriks
- Department of Pulmonary Medicine, Erasmus Medical Center Rotterdam, University Medical Center, Rotterdam, Netherlands
| | - Cornelis van 't Veer
- Center for Experimental and Molecular Medicine (CEMM), Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Amsterdam Infection and Immunity Institute (AI&II), Amsterdam University Medical Centers (UMC), Amsterdam, Netherlands
| | - Tom van der Poll
- Center for Experimental and Molecular Medicine (CEMM), Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Amsterdam Infection and Immunity Institute (AI&II), Amsterdam University Medical Centers (UMC), Amsterdam, Netherlands.,Division of Infectious Diseases, Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Alex F de Vos
- Center for Experimental and Molecular Medicine (CEMM), Amsterdam University Medical Centers (UMC), Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Amsterdam Infection and Immunity Institute (AI&II), Amsterdam University Medical Centers (UMC), Amsterdam, Netherlands
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6
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Perret C, Le Corre N, Castro-Rodriguez JA. Emergent Pneumonia in Children. Front Pediatr 2021; 9:676296. [PMID: 34222146 PMCID: PMC8247473 DOI: 10.3389/fped.2021.676296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/21/2021] [Indexed: 12/11/2022] Open
Abstract
In recent decades there have been multiple pathogens, viruses and bacteria, which have emerged as causal agents of pneumonia affecting adults, albeit less frequently, to children. For the purposes of this article we have classified emerging pathogens as follows: True emerging, to pathogens identified for the very first time affecting human population (SARS-CoV-1, SARS-CoV-2, MERS-CoV, avian influenza, and hantavirus); Re-emerging, to known pathogens which circulation was controlled once, but they have reappeared (measles, tuberculosis, antimicrobial resistant bacteria such as CA-MRSA, Mycoplasma pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and new serotypes of post-vaccine pneumococcal); and finally, those that we have called old known with new presentations, including common pathogens that, in particular condition, have changed their form of presentation (rhinovirus, and non-SARS coronavirus). We will review for each of them their epidemiology, forms of presentation, therapy, and prognosis in children compared to the adult with the aim of being able to recognize them to establish appropriate therapy, prognostics, and effective control measures.
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Affiliation(s)
- Cecilia Perret
- Department of Pediatric Infectious Diseases and Immunology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicole Le Corre
- Department of Pediatric Infectious Diseases and Immunology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jose A Castro-Rodriguez
- Department of Pediatric Pulmonology and Cardiology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
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7
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Luck JN, Tettelin H, Orihuela CJ. Sugar-Coated Killer: Serotype 3 Pneumococcal Disease. Front Cell Infect Microbiol 2020; 10:613287. [PMID: 33425786 PMCID: PMC7786310 DOI: 10.3389/fcimb.2020.613287] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022] Open
Abstract
Capsular polysaccharide (CPS), which surrounds the bacteria, is one of the most significant and multifaceted contributors to Streptococcus pneumoniae virulence. Capsule prevents entrapment in mucus during colonization, traps water to protect against desiccation, can serve as an energy reserve, and protects the bacterium against complement-mediated opsonization and immune cell phagocytosis. To date, 100 biochemically and serologically distinct capsule types have been identified for S. pneumoniae; 20 to 30 of which have well-defined propensity to cause opportunistic human infection. Among these, serotype 3 is perhaps the most problematic as serotype 3 infections are characterized as having severe clinical manifestations including empyema, bacteremia, cardiotoxicity, and meningitis; consequently, with a fatality rate of 30%-47%. Moreover, serotype 3 resists antibody-mediated clearance despite its inclusion in the current 13-valent conjugate vaccine formulation. This review covers the role of capsule in pneumococcal pathogenesis and the importance of serotype 3 on human disease. We discuss how serotype 3 capsule synthesis and presentation on the bacterial surface is distinct from other serotypes, the biochemical and physiological properties of this capsule type that facilitate its ability to cause disease, and why existing vaccines are unable to confer protection. We conclude with discussion of the clonal properties of serotype 3 and how these have changed since introduction of the 13-valent vaccine in 2000.
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Affiliation(s)
- Jennifer N. Luck
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Hervé Tettelin
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Carlos J. Orihuela
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States
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8
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Bradshaw JL, Rafiqullah IM, Robinson DA, McDaniel LS. Transformation of nonencapsulated Streptococcus pneumoniae during systemic infection. Sci Rep 2020; 10:18932. [PMID: 33144660 PMCID: PMC7641166 DOI: 10.1038/s41598-020-75988-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/16/2020] [Indexed: 11/24/2022] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is a principal cause of bacterial middle ear infections, pneumonia, and meningitis. Capsule-targeted pneumococcal vaccines have likely contributed to increased carriage of nonencapsulated S. pneumoniae (NESp). Some NESp lineages are associated with highly efficient DNA uptake and transformation frequencies. However, NESp strains lack capsule that may increase disease severity. We tested the hypothesis that NESp could acquire capsule during systemic infection and transform into more virulent pneumococci. We reveal that NESp strains MNZ67 and MNZ41 are highly transformable and resistant to multiple antibiotics. Natural transformation of NESp when co-administered with heat-killed encapsulated strain WU2 in a murine model of systemic infection resulted in encapsulation of NESp and increased virulence during bacteremia. Functional capsule production increased the pathogenic potential of MNZ67 by significantly decreasing complement deposition on the bacterial surface. However, capsule acquisition did not further decrease complement deposition on the relatively highly pathogenic strain MNZ41. Whole genome sequencing of select transformants demonstrated that recombination of up to 56.7 kbp length occurred at the capsule locus, along with additional recombination occurring at distal sites harboring virulence-associated genes. These findings indicate NESp can compensate for lack of capsule production and rapidly evolve into more virulent strains.
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Affiliation(s)
- Jessica L Bradshaw
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, USA.,Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Iftekhar M Rafiqullah
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, USA
| | - D Ashley Robinson
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Larry S McDaniel
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, USA.
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9
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Kashyap D, Baral B, Verma TP, Sonkar C, Chatterji D, Jain AK, Jha HC. Oral rinses in growth inhibition and treatment of Helicobacter pylori infection. BMC Microbiol 2020; 20:45. [PMID: 32131741 PMCID: PMC7055109 DOI: 10.1186/s12866-020-01728-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 02/14/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Helicobacter pylori (H. pylori) is well-known for its role in chronic gastritis and gastric cancer. Eradication of these carcinogenic bacteria from the gut is one of the challenges for clinicians. The complexity of treatment mainly owes to antibiotic resistance and relapse due to an additional reservoir in the oral cavity. Our study emphases the isolation of H. pylori from distinct habitats of the gut microenvironment (gastric biopsy and gastric juice) and its subsequent characterization. We have also evaluated the effect of various oral rinses on isolated H. pylori from different anatomical locations of included subjects. RESULTS The possible strains isolated from two different habitats of the same subject shows a striking difference in their growth pattern. Promisingly, some of the included oral rinses are efficient in growth inhibition as per recommended 30 s treatment. The subsequent evaluation shows that oral rinse B (among A-E) is most effective and down-regulates the expression of one of the potent H. pylori gene, CagA, in the infected gastric adenocarcinoma (AGS) cells. CONCLUSION Our study, for the first time, revealed that H. pylori, isolated from the different habitat of the same subject, show a different growth pattern. The expression of H. pylori pathogenic gene (CagA) was down-regulated by the use of oral rinses. Hence, oral rinses will reduce the H. pylori in the oral cavity and help to control its migration from oral to the gastric compartment and may be used as an adjuvant treatment option for its re-infection.
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Affiliation(s)
- Dharmendra Kashyap
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, 453552, Indore, Madhya Pradesh, India
| | - Budhadev Baral
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, 453552, Indore, Madhya Pradesh, India
| | - Tarun Prakash Verma
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, 453552, Indore, Madhya Pradesh, India
| | - Charu Sonkar
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, 453552, Indore, Madhya Pradesh, India
| | - Debi Chatterji
- Choithram Hospital and Research Centre, 452014, Indore, Madhya Pradesh, India
| | - Ajay Kumar Jain
- Choithram Hospital and Research Centre, 452014, Indore, Madhya Pradesh, India
| | - Hem C Jha
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, 453552, Indore, Madhya Pradesh, India.
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10
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Shenoy AT, Wasserman GA, Arafa EI, Wooten AK, Smith NM, Martin IM, Jones MR, Quinton LJ, Mizgerd JP. Lung CD4 + resident memory T cells remodel epithelial responses to accelerate neutrophil recruitment during pneumonia. Mucosal Immunol 2020; 13:334-343. [PMID: 31748706 PMCID: PMC7044037 DOI: 10.1038/s41385-019-0229-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 11/04/2019] [Indexed: 02/04/2023]
Abstract
Previous pneumococcal experience establishes lung-resident IL-17A-producing CD4+ memory TRM cells that accelerate neutrophil recruitment against heterotypic pneumococci. Herein, we unravel a novel crosstalk between CD4+ TRM cells and lung epithelial cells underlying this protective immunity. Depletion of CD4+ cells in pneumococcus-experienced mice diminished CXCL5 (but not CXCL1 or CXCL2) and downstream neutrophil accumulation in the lungs. Epithelial cells from experienced lungs exhibited elevated mRNA for CXCL5 but not other epithelial products such as GM-CSF or CCL20, suggesting a skewing by CD4+ TRM cells. Genome-wide expression analyses revealed a significant remodeling of the epithelial transcriptome of infected lungs due to infection history, ~80% of which was CD4+ cell-dependent. The CD4+ TRM cell product IL-17A stabilized CXCL5 but not GM-CSF or CCL20 mRNA in cultured lung epithelial cells, implicating posttranscriptional regulation as a mechanism for altered epithelial responses. These results suggest that epithelial cells in experienced lungs are effectively different, owing to their communication with TRM cells. Our study highlights the role of tissue-resident adaptive immune cells in fine-tuning epithelial functions to hasten innate immune responses and optimize defense in experienced lungs, a concept that may apply broadly to mucosal immunology.
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Affiliation(s)
- Anukul T. Shenoy
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Gregory A. Wasserman
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Emad I. Arafa
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Alicia K. Wooten
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Nicole M.S. Smith
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Ian M.C. Martin
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Matthew R. Jones
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Lee J. Quinton
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Joseph P. Mizgerd
- Pulmonary Center, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA.,Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.,CORRESPONDING AUTHOR: Joseph P. Mizgerd, Sc.D., Pulmonary Center, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118 USA, Phone: (617)-358-1186; Fax: (617)-638-5227,
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11
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Slack TJ, Li W, Shi D, McArthur JB, Zhao G, Li Y, Xiao A, Khedri Z, Yu H, Liu Y, Chen X. Triazole-linked transition state analogs as selective inhibitors against V. cholerae sialidase. Bioorg Med Chem 2018; 26:5751-5757. [PMID: 30389408 PMCID: PMC6326775 DOI: 10.1016/j.bmc.2018.10.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/15/2018] [Accepted: 10/26/2018] [Indexed: 01/07/2023]
Abstract
Sialidases or neuraminidases are enzymes that catalyze the cleavage of terminal sialic acids from oligosaccharides and glycoconjugates. They play important roles in bacterial and viral infection and have been attractive targets for drug development. Structure-based drug design has led to potent inhibitors against neuraminidases of influenza A viruses that have been used successfully as approved therapeutics. However, selective and effective inhibitors against bacterial and human sialidases are still being actively pursued. Guided by crystal structural analysis, several derivatives of 2-deoxy-2,3-didehydro-N-acetylneuraminic acid (Neu5Ac2en or DANA) were designed and synthesized as triazole-linked transition state analogs. Inhibition studies revealed that glycopeptide analog E-(TriazoleNeu5Ac2en)-AKE and compound (TriazoleNeu5Ac2en)-A were selective inhibitors against Vibrio cholerae sialidase, while glycopeptide analog (TriazoleNeu5Ac2en)-AdE selectively inhibited Vibrio cholerae and A. ureafaciens sialidases.
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Affiliation(s)
- Teri J. Slack
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA,These authors contributed equality to this work
| | - Wanqing Li
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA,These authors contributed equality to this work
| | - Dashuang Shi
- Center for Genetic Medicine Research, Children’s National Medical Center, 111 Michigan Ave, NW, Washington DC 20012, USA
| | - John B. McArthur
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Gengxiang Zhao
- Center for Genetic Medicine Research, Children’s National Medical Center, 111 Michigan Ave, NW, Washington DC 20012, USA
| | - Yanhong Li
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - An Xiao
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Zahra Khedri
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Hai Yu
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Yang Liu
- Center for Genetic Medicine Research, Children’s National Medical Center, 111 Michigan Ave, NW, Washington DC 20012, USA
| | - Xi Chen
- Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA,Corresponding author. Tel: +1 530 754 6037; fax: +1 530 752 8995. (X. Chen)
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12
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Manna S, Waring A, Papanicolaou A, Hall NE, Bozinovski S, Dunne EM, Satzke C. The transcriptomic response of Streptococcus pneumoniae following exposure to cigarette smoke extract. Sci Rep 2018; 8:15716. [PMID: 30356075 PMCID: PMC6200755 DOI: 10.1038/s41598-018-34103-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/11/2018] [Indexed: 11/09/2022] Open
Abstract
Exposure to cigarette smoke is a risk factor for respiratory diseases. Although most research has focused on its effects on the host, cigarette smoke can also directly affect respiratory pathogens, in some cases enhancing virulence. Streptococcus pneumoniae (the pneumococcus) is a leading cause of community-acquired pneumonia worldwide, however data on the effects of cigarette smoke on the pneumococcus are sparse. Using RNA-seq, we show that pneumococci exposed to cigarette smoke extract in a concentrated acute exposure in vitro model initiate a 'survival' transcriptional response including the upregulation of detoxification enzymes, efflux pumps and osmoregulator transporters, as well as the downregulation of fatty acid and D-alanyl lipoteichoic acid biosynthesis genes. Except for the downregulation of the pneumolysin gene, there were no changes in the expression of major virulence factors following exposure to cigarette smoke. Compared to unexposed pneumococci, smoke-exposed pneumococci did not exhibit any changes in viability, adherence, hydrophobicity or cell lysis susceptibility. In this study, we demonstrate that pneumococci adapt to acute noxious cigarette smoke exposure by inducing a gene expression signature that allows the bacteria to resist its harmful effects.
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Affiliation(s)
- Sam Manna
- Pneumococcal Research, Murdoch Children's Research Institute, Infection and Immunity, Parkville, 3052, Australia.
| | - Alicia Waring
- Pneumococcal Research, Murdoch Children's Research Institute, Infection and Immunity, Parkville, 3052, Australia
| | - Angelica Papanicolaou
- Chronic Infectious and Inflammatory Disease Programme, School of Health & Biomedical Sciences, RMIT University, Bundoora, 3083, Australia
| | - Nathan E Hall
- Department of Animal, Plant and Soil Sciences, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Steven Bozinovski
- Chronic Infectious and Inflammatory Disease Programme, School of Health & Biomedical Sciences, RMIT University, Bundoora, 3083, Australia
| | - Eileen M Dunne
- Pneumococcal Research, Murdoch Children's Research Institute, Infection and Immunity, Parkville, 3052, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, 3052, Australia
| | - Catherine Satzke
- Pneumococcal Research, Murdoch Children's Research Institute, Infection and Immunity, Parkville, 3052, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, 3052, Australia.,Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, 3010, Australia
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13
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Shenoy AT, Beno SM, Brissac T, Bell JW, Novak L, Orihuela CJ. Severity and properties of cardiac damage caused by Streptococcus pneumoniae are strain dependent. PLoS One 2018; 13:e0204032. [PMID: 30216364 PMCID: PMC6138390 DOI: 10.1371/journal.pone.0204032] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/31/2018] [Indexed: 01/15/2023] Open
Abstract
Streptococcus pneumoniae is an opportunistic Gram-positive pathogen that can cause invasive disease. Recent studies have shown that S. pneumoniae is able to invade the myocardium and kill cardiomyocytes, with one-in-five adults hospitalized for pneumococcal pneumonia having a pneumonia-associated adverse cardiac event. Furthermore, clinical reports have shown up to a 10-year increased risk of adverse cardiac events in patients formerly hospitalized for pneumococcal bacteremia. In this study, we investigated the ability of nine S. pneumoniae clinical isolates, representing eight unique serotypes, to cause cardiac damage in a mouse model of invasive disease. Following intraperitoneal challenge of C57BL/6 mice, four of these strains (D39, WU2, TIGR4, and 6A-10) caused high-grade bacteremia, while CDC7F:2617-97 and AMQ16 caused mid- and low-grade bacteremia, respectively. Three strains did not cause any discernible disease. Of note, only the strains capable of high-grade bacteremia caused cardiac damage, as inferred by serum levels of cardiac troponin-I. This link between bacteremia and heart damage was further corroborated by Hematoxylin & Eosin and Trichrome staining which showed cardiac cytotoxicity only in D39, WU2, TIGR4, and 6A-10 infected mice. Finally, hearts infected with these strains showed varying histopathological characteristics, such as differential lesion formation and myocytolysis, suggesting that the mechanism of heart damage varied between strains.
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Affiliation(s)
- Anukul T. Shenoy
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Sarah M. Beno
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Terry Brissac
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jeremiah W. Bell
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Lea Novak
- Department of Pathology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Carlos J. Orihuela
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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14
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Nakamya MF, Ayoola MB, Park S, Shack LA, Swiatlo E, Nanduri B. The Role of Cadaverine Synthesis on Pneumococcal Capsule and Protein Expression. Med Sci (Basel) 2018; 6:E8. [PMID: 29351189 PMCID: PMC5872165 DOI: 10.3390/medsci6010008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 01/07/2018] [Accepted: 01/09/2018] [Indexed: 12/25/2022] Open
Abstract
Invasive infections caused by Streptococcus pneumoniae, a commensal in the nasopharynx, pose significant risk to human health. Limited serotype coverage by the available polysaccharide-based conjugate vaccines coupled with increasing incidence of antibiotic resistance complicates therapeutic strategies. Bacterial physiology and metabolism that allows pathogens to adapt to the host are a promising avenue for the discovery of novel therapeutics. Intracellular polyamine concentrations are tightly regulated by biosynthesis, transport and degradation. We previously reported that deletion of cadA, a gene that encodes for lysine decarboxylase, an enzyme that catalyzes cadaverine synthesis results in an attenuated phenotype. Here, we report the impact of cadA deletion on pneumococcal capsule and protein expression. Our data show that genes for polyamine biosynthesis and transport are downregulated in ∆cadA. Immunoblot assays show reduced capsule in ∆cadA. Reduced capsule synthesis could be due to reduced transcription and availability of precursors for synthesis. The capsule is the predominant virulence factor in pneumococci and is critical for evading opsonophagocytosis and its loss in ∆cadA could explain the reported attenuation in vivo. Results from this study show that capsule synthesis in pneumococci is regulated by polyamine metabolism, which can be targeted for developing novel therapies.
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Affiliation(s)
- Mary F Nakamya
- Department of Basic Sciences, College of Veterinary Medicine, P.O. Box 6100, Mississippi State, MS 39762, USA.
| | - Moses B Ayoola
- Department of Basic Sciences, College of Veterinary Medicine, P.O. Box 6100, Mississippi State, MS 39762, USA.
| | - Seongbin Park
- Department of Basic Sciences, College of Veterinary Medicine, P.O. Box 6100, Mississippi State, MS 39762, USA.
| | - Leslie A Shack
- Department of Basic Sciences, College of Veterinary Medicine, P.O. Box 6100, Mississippi State, MS 39762, USA.
| | - Edwin Swiatlo
- Section of Infectious Diseases, Southeast Louisiana Veterans Health Care System, New Orleans, LA 70112, USA.
| | - Bindu Nanduri
- Department of Basic Sciences, College of Veterinary Medicine, P.O. Box 6100, Mississippi State, MS 39762, USA.
- Institute for Genomics, Biocomputing & Biotechnology, Mississippi State University, Mississippi State, MS 39762, USA.
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15
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Hare KM, Leach AJ, Smith-Vaughan HC, Chang AB, Grimwood K. Streptococcus pneumoniae and chronic endobronchial infections in childhood. Pediatr Pulmonol 2017; 52:1532-1545. [PMID: 28922566 DOI: 10.1002/ppul.23828] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 08/06/2017] [Indexed: 01/03/2023]
Abstract
Streptococcus pneumoniae (pneumococcus) is the main cause of bacterial pneumonia worldwide and has been studied extensively in this context. However, its role in chronic endobronchial infections and accompanying lower airway neutrophilic infiltration has received little attention. Severe and recurrent pneumonia are risk factors for chronic suppurative lung disease (CSLD) and bronchiectasis; the latter causes considerable morbidity and, in some populations, premature death in children and adults. Protracted bacterial bronchitis (PBB) is another chronic endobronchial infection associated with substantial morbidity. In some children, PBB may progress to bronchiectasis. Although nontypeable Haemophilus influenzae is the main pathogen in PBB, CSLD and bronchiectasis, pneumococci are isolated commonly from the lower airways of children with these diagnoses. Here we review what is known currently about pneumococci in PBB, CSLD and bronchiectasis, including the importance of pneumococcal nasopharyngeal colonization and how persistence in the lower airways may contribute to the pathogenesis of these chronic pulmonary disorders. Antibiotic treatments, particularly long-term azithromycin therapy, are discussed together with antibiotic resistance and the impact of pneumococcal conjugate vaccines. Important areas requiring further investigation are identified, including immune responses associated with pneumococcal lower airway infection, alone and in combination with other respiratory pathogens, and microarray serotyping to improve detection of carriage and infection by multiple serotypes. Genome wide association studies of pneumococci from the upper and lower airways will help identify virulence and resistance determinants, including potential therapeutic targets and vaccine antigens to treat and prevent endobronchial infections. Much work is needed, but the benefits will be substantial.
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Affiliation(s)
- Kim M Hare
- Child Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Amanda J Leach
- Child Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Heidi C Smith-Vaughan
- Child Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia.,School of Medicine, Griffith University, Gold Coast, Queensland, Australia
| | - Anne B Chang
- Child Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia.,Department of Respiratory Medicine, Lady Cilento Children's Hospital, Brisbane, Queensland, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Keith Grimwood
- School of Medicine, Griffith University, Gold Coast, Queensland, Australia.,Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia.,Gold Coast Health, Gold Coast, Queensland, Australia
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16
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Shenoy AT, Brissac T, Gilley RP, Kumar N, Wang Y, Gonzalez-Juarbe N, Hinkle WS, Daugherty SC, Shetty AC, Ott S, Tallon LJ, Deshane J, Tettelin H, Orihuela CJ. Streptococcus pneumoniae in the heart subvert the host response through biofilm-mediated resident macrophage killing. PLoS Pathog 2017; 13:e1006582. [PMID: 28841717 PMCID: PMC5589263 DOI: 10.1371/journal.ppat.1006582] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 09/07/2017] [Accepted: 08/15/2017] [Indexed: 11/18/2022] Open
Abstract
For over 130 years, invasive pneumococcal disease has been associated with the presence of extracellular planktonic pneumococci, i.e. diplococci or short chains in affected tissues. Herein, we show that Streptococcus pneumoniae that invade the myocardium instead replicate within cellular vesicles and transition into non-purulent biofilms. Pneumococci within mature cardiac microlesions exhibited salient biofilm features including intrinsic resistance to antibiotic killing and the presence of an extracellular matrix. Dual RNA-seq and subsequent principal component analyses of heart- and blood-isolated pneumococci confirmed the biofilm phenotype in vivo and revealed stark anatomical site-specific differences in virulence gene expression; the latter having major implications on future vaccine antigen selection. Our RNA-seq approach also identified three genomic islands as exclusively expressed in vivo. Deletion of one such island, Region of Diversity 12, resulted in a biofilm-deficient and highly inflammogenic phenotype within the heart; indicating a possible link between the biofilm phenotype and a dampened host-response. We subsequently determined that biofilm pneumococci released greater amounts of the toxin pneumolysin than did planktonic or RD12 deficient pneumococci. This allowed heart-invaded wildtype pneumococci to kill resident cardiac macrophages and subsequently subvert cytokine/chemokine production and neutrophil infiltration into the myocardium. This is the first report for pneumococcal biofilm formation in an invasive disease setting. We show that biofilm pneumococci actively suppress the host response through pneumolysin-mediated immune cell killing. As such, our findings contradict the emerging notion that biofilm pneumococci are passively immunoquiescent.
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Affiliation(s)
- Anukul T. Shenoy
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States of America
- Department of Microbiology, Immunology, and Molecular Genetics, The University of Texas Health San Antonio, San Antonio, TX, United States of America
| | - Terry Brissac
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Ryan P. Gilley
- Department of Microbiology, Immunology, and Molecular Genetics, The University of Texas Health San Antonio, San Antonio, TX, United States of America
| | - Nikhil Kumar
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Yong Wang
- Division of Pulmonary, Allergy & Critical Care Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Norberto Gonzalez-Juarbe
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Whitney S. Hinkle
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Sean C. Daugherty
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Amol C. Shetty
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Sandra Ott
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Luke J. Tallon
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Jessy Deshane
- Division of Pulmonary, Allergy & Critical Care Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Hervé Tettelin
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Carlos J. Orihuela
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States of America
- Department of Microbiology, Immunology, and Molecular Genetics, The University of Texas Health San Antonio, San Antonio, TX, United States of America
- * E-mail:
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17
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Masters IB, Isles AF, Grimwood K. Necrotizing pneumonia: an emerging problem in children? Pneumonia (Nathan) 2017; 9:11. [PMID: 28770121 PMCID: PMC5525269 DOI: 10.1186/s41479-017-0035-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 06/22/2017] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND In children, necrotizing pneumonia (NP) is an uncommon, severe complication of pneumonia. It is characterized by destruction of the underlying lung parenchyma resulting in multiple small, thin-walled cavities and is often accompanied by empyema and bronchopleural fistulae. REVIEW NP in children was first reported in children in 1994, and since then there has been a gradual increase in cases, which is partially explained by greater physician awareness and use of contrast computed tomography (CT) scans, and by temporal changes in circulating respiratory pathogens and antibiotic prescribing. The most common pathogens detected in children with NP are pneumococci and Staphylococcus aureus. The underlying disease mechanisms are poorly understood, but likely relate to multiple host susceptibility and bacterial virulence factors, with viral-bacterial interactions also possibly having a role. Most cases are in previously healthy young children who, despite adequate antibiotic therapy for bacterial pneumonia, remain febrile and unwell. Many also have evidence of pleural effusion, empyema, or pyopneumothorax, which has undergone drainage or surgical intervention without clinical improvement. The diagnosis is generally made by chest imaging, with CT scans being the most sensitive, showing loss of normal pulmonary architecture, decreased parenchymal enhancement and multiple thin-walled cavities. Blood culture and culture and molecular testing of pleural fluid provide a microbiologic diagnosis in as many as 50% of cases. Prolonged antibiotics, draining pleural fluid and gas that causes mass effects, and maintaining ventilation, circulation, nutrition, fluid, and electrolyte balance are critical components of therapy. Despite its serious nature, death is uncommon, with good clinical, radiographic and functional recovery achieved in the 5-6 months following diagnosis. Increased knowledge of NP's pathogenesis will assist more rapid diagnosis and improve treatment and, ultimately, prevention. CONCLUSION It is important to consider that our understanding of NP is limited to individual case reports or small case series, and treatment data from randomized-controlled trials are lacking. Furthermore, case series are retrospective and usually confined to single centers. Consequently, these studies may not be representative of patients in other locations, especially when allowing for temporal changes in pathogen behaviour and differences in immunization schedules and antibiotic prescribing practices.
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Affiliation(s)
- I. Brent Masters
- Department of Respiratory and Sleep Medicine, Lady Cilento Children’s Hospital, South Brisbane, QLD Australia
| | - Alan F. Isles
- Department of Respiratory and Sleep Medicine, Lady Cilento Children’s Hospital, South Brisbane, QLD Australia
| | - Keith Grimwood
- School of Medicine and Menzies Health Institute Queensland, Gold Coast campus, Griffith University, Building G40, Southport Gold Coast, QLD Australia
- Departments of Infectious Diseases and Paediatrics, Gold Coast Health, Southport Gold Coast, QLD Australia
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18
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Nagaraj G, Ganaie F, Govindan V, Ravikumar KL. Development of PCRSeqTyping-a novel molecular assay for typing of Streptococcus pneumoniae. Pneumonia (Nathan) 2017; 9:8. [PMID: 28702310 PMCID: PMC5471960 DOI: 10.1186/s41479-017-0032-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 05/01/2017] [Indexed: 11/25/2022] Open
Abstract
Background Precise serotyping of pneumococci is essential for vaccine development, to better understand the pathogenicity and trends of drug resistance. Currently used conventional and molecular methods of serotyping are expensive and time-consuming, with limited coverage of serotypes. An accurate and rapid serotyping method with complete coverage of serotypes is an urgent necessity. This study describes the development and application of a novel technology that addresses this need. Methods Polymerase chain reaction (PCR) was performed, targeting 1061 bp cpsB region, and the amplicon was subjected to sequencing. The sequence data was analyzed using the National Centre for Biotechnology Information database. For homologous strains, a second round of PCR, sequencing, and data analysis was performed targeting 10 group-specific genes located in the capsular polysaccharide region. Ninety-one pneumococcal reference strains were analyzed with PCRSeqTyping and compared with Quellung reaction using Pneumotest Kit (SSI, Denmark). Results A 100% correlation of PCRSeqTyping results was observed with Pneumotest results. Fifty-nine reference strains were uniquely identified in the first step of PCRSeqTyping. The remaining 32 homologous strains out of 91 were also uniquely identified in the second step. Conclusion This study describes a PCRSeqTyping assay that is accurate and rapid, with high reproducibility. This assay is amenable for clinical testing and does not require culturing of the samples. It is a significant improvement over other methods because it covers all pneumococcal serotypes, and it has the potential for use in diagnostic laboratories and surveillance studies.
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Affiliation(s)
- Geetha Nagaraj
- Central Research Laboratory, KIMS Hospital and Research Centre, KR Road, VV Purum, Bangalore, Karnataka 560 004 India
| | - Feroze Ganaie
- Central Research Laboratory, KIMS Hospital and Research Centre, KR Road, VV Purum, Bangalore, Karnataka 560 004 India
| | - Vandana Govindan
- Central Research Laboratory, KIMS Hospital and Research Centre, KR Road, VV Purum, Bangalore, Karnataka 560 004 India
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19
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Pizzutto SJ, Hare KM, Upham JW. Bronchiectasis in Children: Current Concepts in Immunology and Microbiology. Front Pediatr 2017; 5:123. [PMID: 28611970 PMCID: PMC5447051 DOI: 10.3389/fped.2017.00123] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 05/08/2017] [Indexed: 12/26/2022] Open
Abstract
Bronchiectasis is a complex chronic respiratory condition traditionally characterized by chronic infection, airway inflammation, and progressive decline in lung function. Early diagnosis and intensive treatment protocols can stabilize or even improve the clinical prognosis of children with bronchiectasis. However, understanding the host immunologic mechanisms that contribute to recurrent infection and prolonged inflammation has been identified as an important area of research that would contribute substantially to effective prevention strategies for children at risk of bronchiectasis. This review will focus on the current understanding of the role of the host immune response and important pathogens in the pathogenesis of bronchiectasis (not associated with cystic fibrosis) in children.
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Affiliation(s)
- Susan J Pizzutto
- Child Health Division, Menzies School of Health Research, Darwin, NT, Australia
| | - Kim M Hare
- Child Health Division, Menzies School of Health Research, Darwin, NT, Australia
| | - John W Upham
- Department of Respiratory Medicine, Princess Alexandra Hospital, Brisbane, QLD, Australia.,School of Medicine, The University of Queensland, Brisbane, QLD, Australia
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