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Loza L, Doering TL. A fungal protein organizes both glycogen and cell wall glucans. Proc Natl Acad Sci U S A 2024; 121:e2319707121. [PMID: 38743622 PMCID: PMC11126952 DOI: 10.1073/pnas.2319707121] [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: 11/10/2023] [Accepted: 04/09/2024] [Indexed: 05/16/2024] Open
Abstract
Glycogen is a glucose storage molecule composed of branched α-1,4-glucan chains, best known as an energy reserve that can be broken down to fuel central metabolism. Because fungal cells have a specialized need for glucose in building cell wall glucans, we investigated whether glycogen is used for this process. For these studies, we focused on the pathogenic yeast Cryptococcus neoformans, which causes ~150,000 deaths per year worldwide. We identified two proteins that influence formation of both glycogen and the cell wall: glycogenin (Glg1), which initiates glycogen synthesis, and a protein that we call Glucan organizing enzyme 1 (Goe1). We found that cells missing Glg1 lack α-1,4-glucan in their walls, indicating that this material is derived from glycogen. Without Goe1, glycogen rosettes are mislocalized and β-1,3-glucan in the cell wall is reduced. Altogether, our results provide mechanisms for a close association between glycogen and cell wall.
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Affiliation(s)
- Liza Loza
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO63110
| | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO63110
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2
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Zhou S, Che J, Wang X, Lin Y, Niu J, Liang W, Xu L, Zhang M, Liao Y, Shao Z, Li Q. Identification of pneumococcal serotypes with individual recognition of vaccine types by a highly multiplexed real-time PCR-based MeltArray approach. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2024; 57:107-117. [PMID: 37919170 DOI: 10.1016/j.jmii.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 09/07/2023] [Accepted: 10/24/2023] [Indexed: 11/04/2023]
Abstract
BACKGROUND Pneumococcus serotyping is important for monitoring serotype epidemiology, vaccine-induced serotypes replacement and emerging pathogenic serotypes. However, the lack of high-resolution serotyping tools has hindered its widespread implementation. METHODS We devised a single-step, multiplex real-time polymerase chain reaction (PCR)-based MeltArray approach termed PneumoSero that can identify 92 serotypes with individual recognition of 54 serotypes, including all 24 currently available vaccine types. The limit of detection (LOD) and the ability to coexisting serotypes were studied, followed by analytical evaluation using 92 reference pneumococcal strains and 125 non-pneumococcal strains, and clinical evaluation using 471 pneumococcus isolates and 46 pneumococcus-positive clinical samples. RESULTS The LODs varied with serotypes from 50 to 100 copies per reaction and 10 % of the minor serotypes were detectable in samples containing two mixed serotypes. Analytical evaluation presented 100 % accuracy in both 92 reference pneumococcal strains and 125 non-pneumococcal strains. Clinical evaluation of 471 pneumococcus isolates displayed full concordance with Sanger sequencing results. The 46 clinical specimens yielded 45 typeable results and one untypeable result. Of the 45 typeable samples, 41 were of a single serotype and four were of mixed serotypes, all of which were confirmed by Sanger sequencing or separate PCR assays. CONCLUSION We conclude that the PneumoSero assay can be implemented as a routine tool for pneumococcal serotyping in standard microbiology laboratories and even in clinical settings.
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Affiliation(s)
- Shujuan Zhou
- Engineering Research Centre of Molecular Diagnostics of the Ministry of Education, State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen, China
| | - Jie Che
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xuran Wang
- Engineering Research Centre of Molecular Diagnostics of the Ministry of Education, State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen, China
| | - Yong Lin
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Jianjun Niu
- Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China
| | - Weitong Liang
- Engineering Research Centre of Molecular Diagnostics of the Ministry of Education, State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen, China
| | - Li Xu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Maojun Zhang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yiqun Liao
- Engineering Research Centre of Molecular Diagnostics of the Ministry of Education, State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen, China; School of Public Health, Xiamen University, Xiamen, China.
| | - Zhujun Shao
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
| | - Qingge Li
- Engineering Research Centre of Molecular Diagnostics of the Ministry of Education, State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen, China.
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3
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Henares D, Lo SW, Perez-Argüello A, Redin A, Ciruela P, Garcia-Garcia JJ, Brotons P, Yuste J, Sá-Leão R, Muñoz-Almagro C. Comparison of next generation technologies and bioinformatics pipelines for capsular typing of Streptococcus pneumoniae. J Clin Microbiol 2023; 61:e0074123. [PMID: 38092657 PMCID: PMC10729682 DOI: 10.1128/jcm.00741-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 10/01/2023] [Indexed: 12/20/2023] Open
Abstract
Whole genome sequencing (WGS)-based approaches for pneumococcal capsular typing have become an alternative to serological methods. In silico serotyping from WGS has not yet been applied to long-read sequences produced by third-generation technologies. The objective of the study was to determine the capsular types of pneumococci causing invasive disease in Catalonia (Spain) using serological typing and WGS and to compare the performance of different bioinformatics pipelines using short- and long-read data from WGS. All invasive pneumococcal pediatric isolates collected in Hospital Sant Joan de Déu (Barcelona) from 2013 to 2019 were included. Isolates were assigned a capsular type by serological testing based on anticapsular antisera and by different WGS-based pipelines: Illumina sequencing followed by serotyping with PneumoCaT, SeroBA, and Pathogenwatch vs MinION-ONT sequencing coupled with serotyping by Pathogenwatch from pneumococcal assembled genomes. A total of 119 out of 121 pneumococcal isolates were available for sequencing. Twenty-nine different serotypes were identified by serological typing, with 24F (n = 17; 14.3%), 14 (n = 10; 8.4%), and 15B/C (n = 8; 6.7%) being the most common serotypes. WGS-based pipelines showed initial concordance with serological typing (>91% of accuracy). The main discrepant results were found at the serotype level within a serogroup: 6A/B, 6C/D, 9A/V, 11A/D, and 18B/C. Only one discrepancy at the serogroup level was observed: serotype 29 by serological testing and serotype 35B/D by all WGS-based pipelines. Thus, bioinformatics WGS-based pipelines, including those using third-generation sequencing, are useful for pneumococcal capsular assignment. Possible discrepancies between serological typing and WGS-based approaches should be considered in pneumococcal capsular-type surveillance studies.
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Affiliation(s)
- Desiree Henares
- Department of RDI Microbiology, Hospital Sant Joan de Déu, Barcelona, Spain
- Infectious Diseases and Microbiome, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
- CIBER Center for Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
| | - Stephanie W. Lo
- Parasites and Microbes Programme, Wellcome Sanger Institute, Hinxton, United Kingdom
- Milner Center for Evolution, Life Sciences Department, University of Bath, Bath, United Kingdom
| | - Amaresh Perez-Argüello
- Department of RDI Microbiology, Hospital Sant Joan de Déu, Barcelona, Spain
- Infectious Diseases and Microbiome, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Alba Redin
- Department of RDI Microbiology, Hospital Sant Joan de Déu, Barcelona, Spain
- Infectious Diseases and Microbiome, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Pilar Ciruela
- CIBER Center for Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
- Surveillance and Public Health Emergency Response, Public Health Agency of Catalonia (ASPCAT), Barcelona, Spain
| | - Juan Jose Garcia-Garcia
- CIBER Center for Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
- Pediatrics Department, Hospital Sant Joan de Déu, Barcelona, Spain
- Department of Surgery and Medical-Surgical Specialties, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Pedro Brotons
- Department of RDI Microbiology, Hospital Sant Joan de Déu, Barcelona, Spain
- Infectious Diseases and Microbiome, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
- CIBER Center for Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
- School of Medicine, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Jose Yuste
- Spanish Pneumococcal Reference Laboratory, National Center for Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- CIBER of Respiratory Diseases (CIBERES), Instituto de salud Carlos III, Madrid, Spain
| | - Raquel Sá-Leão
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Carmen Muñoz-Almagro
- Department of RDI Microbiology, Hospital Sant Joan de Déu, Barcelona, Spain
- Infectious Diseases and Microbiome, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
- CIBER Center for Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain
- School of Medicine, Universitat Internacional de Catalunya, Barcelona, Spain
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Su T, Chua WZ, Liu Y, Fan J, Tan SY, Yang DW, Sham LT. Rewiring the pneumococcal capsule pathway for investigating glycosyltransferase specificity and genetic glycoengineering. SCIENCE ADVANCES 2023; 9:eadi8157. [PMID: 37672581 PMCID: PMC10482335 DOI: 10.1126/sciadv.adi8157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/03/2023] [Indexed: 09/08/2023]
Abstract
Virtually all living cells are covered with glycans. Their structures are primarily controlled by the specificities of glycosyltransferases (GTs). GTs typically adopt one of the three folds, namely, GT-A, GT-B, and GT-C. However, what defines their specificities remain poorly understood. Here, we developed a genetic glycoengineering platform by reprogramming the capsular polysaccharide pathways in Streptococcus pneumoniae to interrogate GT specificity and manipulate glycan structures. Our findings suggest that the central cleft of GT-B enzymes is important for determining acceptor specificity. The constraint of the glycoengineering platform was partially alleviated when the specificity of the precursor transporter was reduced, indicating that the transporter contributes to the overall fidelity of glycan synthesis. We also modified the pneumococcal capsule to produce several medically important mammalian glycans, as well as demonstrated the importance of regiochemistry in a glycosidic linkage on binding lung epithelial cells. Our work provided mechanistic insights into GT specificity and an approach for investigating glycan functions.
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Affiliation(s)
- Tong Su
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Yao Liu
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Jingsong Fan
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117545, Singapore
| | - Si-Yin Tan
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Dai-wen Yang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117545, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
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Ganaie FA, Saad JS, Lo SW, McGee L, Bentley SD, van Tonder AJ, Hawkins P, Keenan JD, Calix JJ, Nahm MH. Discovery and Characterization of Pneumococcal Serogroup 36 Capsule Subtypes, Serotypes 36A and 36B. J Clin Microbiol 2023; 61:e0002423. [PMID: 36971549 PMCID: PMC10117043 DOI: 10.1128/jcm.00024-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/20/2023] [Indexed: 03/29/2023] Open
Abstract
Streptococcus pneumoniae can produce a wide breadth of antigenically diverse capsule types, a fact that poses a looming threat to the success of vaccines that target pneumococcal polysaccharide (PS) capsule. Yet, many pneumococcal capsule types remain undiscovered and/or uncharacterized. Prior sequence analysis of pneumococcal capsule synthesis (cps) loci suggested the existence of capsule subtypes among isolates identified as "serotype 36" according to conventional capsule typing methods. We discovered these subtypes represent two antigenically similar but distinguishable pneumococcal capsule serotypes, 36A and 36B. Biochemical analysis of their capsule PS structure reveals that both have the shared repeat unit backbone [→5)-α-d-Galf-(1→1)-d-Rib-ol-(5→P→6)-β-d-ManpNAc-(1→4)-β-d-Glcp-(1→] with two branching structures. Both serotypes have a β-d-Galp branch to Ribitol. Serotypes 36A and 36B differ by the presence of a α-d-Glcp-(1→3)-β-d-ManpNAc or α-d-Galp-(1→3)-β-d-ManpNAc branch, respectively. Comparison of the phylogenetically distant serogroup 9 and 36 cps loci, which all encode this distinguishing glycosidic bond, revealed that the incorporation of Glcp (in types 9N and 36A) versus Galp (in types 9A, 9V, 9L, and 36B) is associated with the identity of four amino acids in the cps-encoded glycosyltransferase WcjA. Identifying functional determinants of cps-encoded enzymes and their impact on capsule PS structure is key to improving the resolution and reliability of sequencing-based capsule typing methods and discovering novel capsule variants indistinguishable by conventional serotyping methods.
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Affiliation(s)
- Feroze A. Ganaie
- Department of Medicine, Division of Pulmonary/Allergy/Critical Care, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jamil S. Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Stephanie W. Lo
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Lesley McGee
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Stephen D. Bentley
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Andries J. van Tonder
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Paulina Hawkins
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| | - Jeremy D. Keenan
- Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Juan J. Calix
- Department of Medicine, Division of Pulmonary/Allergy/Critical Care, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Moon H. Nahm
- Department of Medicine, Division of Pulmonary/Allergy/Critical Care, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Sackett K, Brown P, Dutta K, Scully IL, Gangolli S, Looi K, Nemani S, Yu AYH, Kleven M, Xie J, Moran J, Pride MW, Anderson AS, Lotvin J. Identification of a Novel Keto Sugar Component in Streptococcus pneumoniae Serotype 12F Capsular Polysaccharide and Impact on Vaccine Immunogenicity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:764-773. [PMID: 36723033 PMCID: PMC9986053 DOI: 10.4049/jimmunol.2100849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 01/09/2023] [Indexed: 02/02/2023]
Abstract
Implementation of conjugate vaccine technology revolutionized the ability to effectively elicit long-lasting immune responses to bacterial capsular polysaccharides. Although expansion of conjugate vaccine serotype coverage is designed to target residual disease burden to pneumococcal serotypes not contained in earlier vaccine versions, details of polysaccharide Ag structure, heterogeneity, and epitope structure components contributing to vaccine-mediated immunity are not always clear. Analysis of Streptococcus pneumoniae serotype 12F polysaccharide by two-dimensional nuclear magnetic resonance spectroscopy and mass spectrometry revealed a partial substitution of N-acetyl-galactosamine by the keto sugar 2-acetamido-2,6-dideoxy-xylo-hexos-4-ulose (Sug) in up to 25% of the repeat units. This substitution was not described in previous published structures for 12F. Screening a series of contemporary 12F strains isolated from humans (n = 17) identified Sug incorporation at varying levels in all strains examined. Thus, partial Sug substitution in S. pneumoniae serotype 12F may have always been present but is now detectable by state-of-the-art analytical techniques. During the steps of conjugation, the serotype 12F Sug epitope is modified by reduction, and both polysaccharide PPSV23 and conjugate PCV20 vaccines contain 12F Ags with little to no Sug epitope. Both PCV20 and PPSV23 vaccines were evaluated for protection against circulating 12F strains with varying amounts of Sug in their repeat unit based on an opsonophagocytic killing assay involving HL-60 cells and rabbit complement. Both vaccines elicited human-derived neutralizing Abs against serotype 12F, independent of Sug level between ∼2 and 25 mol%. These findings suggest that the newly identified serotype 12F Sug epitope is likely not an essential epitope for vaccine-elicited protection.
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Affiliation(s)
- Kelly Sackett
- Pfizer Analytical Research and Development, Groton, CT
| | - Paul Brown
- Pfizer Analytical Research and Development, Chesterfield, MO
| | - Kaushik Dutta
- Pfizer Vaccine Research and Development, Pearl River, NY
| | | | - Seema Gangolli
- Pfizer Vaccine Research and Development, Pearl River, NY
| | - Kelvin Looi
- Pfizer Vaccine Research and Development, Pearl River, NY
| | - Sandeep Nemani
- Pfizer Vaccine Research and Development, Pearl River, NY
| | | | - Mark Kleven
- Pfizer Vaccine Research and Development, Pearl River, NY
| | - Jin Xie
- Pfizer Bioprocess Research and Development, Chesterfield, MO
| | - Justin Moran
- Pfizer Vaccine Research and Development, Pearl River, NY
| | | | | | - Jason Lotvin
- Pfizer Vaccine Research and Development, Pearl River, NY
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Carbon Source-Dependent Changes of the Structure of Streptococcus pneumoniae Capsular Polysaccharide with Serotype 6F. Int J Mol Sci 2021; 22:ijms22094580. [PMID: 33925509 PMCID: PMC8123889 DOI: 10.3390/ijms22094580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 11/30/2022] Open
Abstract
The structure of the exopolysaccharide capsule of Streptococcus pneumoniae is defined by the genetic arrangement of the capsule operon allowing the unequivocal identification of the pneumococcal serotype. Here, we investigated the environment-dependent composition of the polysaccharide structure of S. pneumoniae serotype 6F. When grown in a chemically defined medium (CDM) with glucose versus galactose, the exopolysaccharide capsule of the serotype 6F strains reveals a ratio of 1/0.6 or 1/0.3 for galactose/glucose in the capsule by 1H-NMR analyses, respectively. Increased production of the capsule precursor UDP-glucose has been identified by 31P-NMR in CDM with glucose. Flow cytometric experiments using monoclonal antibodies showed decreased labelling of Hyp6AG4 (specific for serotype 6A) antibodies when 6F is grown in glucose as compared to galactose, which mirrors the 1H-NMR results. Whole-genome sequencing analyses of serotype 6F isolates suggested that the isolates evolved during two different events from serotype 6A during the time when the 13-valent pneumococcal conjugate vaccine (PCV-13) was introduced. In conclusion, this study shows differences in the capsular structure of serotype 6F strains using glucose as compared to galactose as the carbon source. Therefore, 6F strains may show slightly different polysaccharide composition while colonizing the human nasopharynx (galactose rich) as compared to invasive locations such as the blood (glucose rich).
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8
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Su T, Nakamoto R, Chun YY, Chua WZ, Chen JH, Zik JJ, Sham LT. Decoding capsule synthesis in Streptococcus pneumoniae. FEMS Microbiol Rev 2020; 45:6041728. [PMID: 33338218 DOI: 10.1093/femsre/fuaa067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 12/07/2020] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pneumoniae synthesizes more than one hundred types of capsular polysaccharides (CPS). While the diversity of the enzymes and transporters involved is enormous, it is not limitless. In this review, we summarized the recent progress on elucidating the structure-function relationships of CPS, the mechanisms by which they are synthesized, how their synthesis is regulated, the host immune response against them, and the development of novel pneumococcal vaccines. Based on the genetic and structural information available, we generated provisional models of the CPS repeating units that remain unsolved. In addition, to facilitate cross-species comparisons and assignment of glycosyltransferases, we illustrated the biosynthetic pathways of the known CPS in a standardized format. Studying the intricate steps of pneumococcal CPS assembly promises to provide novel insights for drug and vaccine development as well as improve our understanding of related pathways in other species.
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Affiliation(s)
- Tong Su
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Rei Nakamoto
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Ye Yu Chun
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Wan Zhen Chua
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Jia Hui Chen
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Justin J Zik
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
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9
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Deo D, Davray D, Kulkarni R. A Diverse Repertoire of Exopolysaccharide Biosynthesis Gene Clusters in Lactobacillus Revealed by Comparative Analysis in 106 Sequenced Genomes. Microorganisms 2019; 7:E444. [PMID: 31614693 PMCID: PMC6843789 DOI: 10.3390/microorganisms7100444] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/13/2022] Open
Abstract
Production of exopolysaccharides (EPS) is one of the unique features of Lactobacillus genus. EPS not only have many physiological roles such as in stress tolerance, quorum sensing and biofilm formation, but also have numerous applications in the food and pharmaceutical industries. In this study, we identified and compared EPS biosynthesis gene clusters in 106 sequenced Lactobacillus genomes representing 27 species. Of the 146 identified clusters, only 41 showed the typical generic organization of genes as reported earlier. Hierarchical clustering showed highly varied nature of the clusters in terms of the gene composition; nonetheless, habitat-wise grouping was observed for the gene clusters from host-adapted and nomadic strains. Of the core genes required for EPS biosynthesis, epsA, B, C, D and E showed higher conservation, whereas gt, wzx and wzy showed high variability in terms of the number and composition of the protein families. Analysis of the distribution pattern of the protein families indicated a higher proportion of mutually exclusive families in clusters from host-adapted and nomadic strains, whereas those from the free-living group had very few unique families. Taken together, this analysis highlights high variability in the EPS gene clusters amongst Lactobacillus with some of their properties correlated to the habitats.
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Affiliation(s)
- Dipti Deo
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412 115, India.
| | - Dimple Davray
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412 115, India.
| | - Ram Kulkarni
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412 115, India.
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10
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van Tonder AJ, Gladstone RA, Lo SW, Nahm MH, du Plessis M, Cornick J, Kwambana-Adams B, Madhi SA, Hawkins PA, Benisty R, Dagan R, Everett D, Antonio M, Klugman KP, von Gottberg A, Breiman RF, McGee L, Bentley SD. Putative novel cps loci in a large global collection of pneumococci. Microb Genom 2019; 5. [PMID: 31184299 PMCID: PMC6700660 DOI: 10.1099/mgen.0.000274] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The pneumococcus produces a polysaccharide capsule, encoded by the cps locus, that provides protection against phagocytosis and determines serotype. Nearly 100 serotypes have been identified with new serotypes still being discovered, especially in previously understudied regions. Here we present an analysis of the cps loci of more than 18 000 genomes from the Global Pneumococcal Sequencing (GPS) project with the aim of identifying novel cps loci with the potential to produce previously unrecognized capsule structures. Serotypes were assigned using whole genome sequence data and 66 of the approximately 100 known serotypes were included in the final dataset. Closer examination of each serotype’s sequences identified nine putative novel cps loci (9X, 11X, 16X, 18X1, 18X2, 18X3, 29X, 33X and 36X) found in ~2.6 % of the genomes. The large number and global distribution of GPS genomes provided an unprecedented opportunity to identify novel cps loci and consider their phylogenetic and geographical distribution. Nine putative novel cps loci were identified and examples of each will undergo subsequent structural and immunological analysis.
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Affiliation(s)
- Andries J van Tonder
- Parasites and Microbes, The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Rebecca A Gladstone
- Parasites and Microbes, The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Stephanie W Lo
- Parasites and Microbes, The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Moon H Nahm
- Division of Pulmonary Medicine, Departments of Medicine and Microbiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mignon du Plessis
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, Johannesburg, South Africa.,School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | | | - Shabir A Madhi
- Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Paulina A Hawkins
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Rachel Benisty
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheeba, Beer-Sheva, Israel
| | - Ron Dagan
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheeba, Beer-Sheva, Israel
| | - Dean Everett
- Queens Research Institute, University of Edinburgh, Edinburgh EH8 9YL, UK
| | - Martin Antonio
- Vaccines and Immunity Theme, MRC Unit, Banjul, The Gambia
| | - Keith P Klugman
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Anne von Gottberg
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, Johannesburg, South Africa.,School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Robert F Breiman
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.,Queens Research Institute, University of Edinburgh, Edinburgh EH8 9YL, UK
| | - Lesley McGee
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Stephen D Bentley
- Parasites and Microbes, The Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.,Emory Global Health Institute, Emory University, Atlanta, GA, USA
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- https://www.pneumogen.net/gps/
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11
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Harding CM, Haurat MF, Vinogradov E, Feldman MF. Distinct amino acid residues confer one of three UDP-sugar substrate specificities in Acinetobacter baumannii PglC phosphoglycosyltransferases. Glycobiology 2018; 28:522-533. [PMID: 29668902 DOI: 10.1093/glycob/cwy037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/11/2018] [Indexed: 01/02/2023] Open
Abstract
Acinetobacter baumannii is an opportunistic human pathogen with the highest reported rates of multidrug resistance among Gram-negative pathogens. The capsular polysaccharide of A. baumannii is considered one of its most significant virulence factors providing resistance against complemented-mediated killing. Capsule synthesis in A. baumannii is usually initiated by the phosphoglycosyltransferase PglC. PglC transfers a phosphosugar from a nucleotide diphosphate-sugar to a polyprenol phosphate generating a polyprenol diphosphate-linked monosaccharide. Traditionally, PglC was thought to have stringent specificity towards UDP-N-N'-diacetylbacillosamine (UDP-diNAcBac). In this work we demonstrate that A. baumannii PglC has the ability to utilize three different UDP-sugar substrates: UDP-N-acetylglucosamine (UDP-GlcNAc), UDP-N-acetylgalactosamine (UDP-GalNAc) or UDP-diNAcBac. Using phylogenetic analyses, we first demonstrate that A. baumannii PglC orthologs separate into three distinct clades. Moreover, all members within a clade are predicted to have the same preference for one of the three possible sugar substrates. To experimentally determine the substrate specificity of each clade, we utilized in vivo complementation models and NMR analysis. We demonstrate that UDP-diNAcBac is accommodated by all PglC orthologs, but some orthologs evolved to utilize UDP-GlcNAc or UDP-GalNAc in a clade-dependent manner. Furthermore, we show that a single point mutation can modify the sugar specificity of a PglC ortholog specific for UDP-diNAcBac and that introduction of a non-native PglC ortholog into A. baumannii can generate a new capsule serotype. Collectively, these studies begin to explain why A. baumannii strains have such highly diverse glycan repertoires.
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Affiliation(s)
- Christian M Harding
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA.,VaxNewMo LLC, St. Louis, MO, USA
| | - M Florencia Haurat
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Evgeny Vinogradov
- National Research Council Canada, Human Health Therapeutics, Ottawa, Ontario, Canada
| | - Mario F Feldman
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA.,VaxNewMo LLC, St. Louis, MO, USA
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12
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Manna S, Ortika BD, Dunne EM, Holt KE, Kama M, Russell FM, Hinds J, Satzke C. A novel genetic variant of Streptococcus pneumoniae serotype 11A discovered in Fiji. Clin Microbiol Infect 2017; 24:428.e1-428.e7. [PMID: 28736074 PMCID: PMC5869949 DOI: 10.1016/j.cmi.2017.06.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/13/2017] [Accepted: 06/30/2017] [Indexed: 11/26/2022]
Abstract
Objectives As part of annual cross-sectional Streptococcus pneumoniae carriage surveys in Fiji (2012–2015), we detected pneumococci in over 100 nasopharyngeal swabs that serotyped as ‘11F-like’ by microarray. We examined the genetic basis of this divergence in the 11F-like capsular polysaccharide (cps) locus compared to the reference 11F cps sequence. The impact of this diversity on capsule phenotype, and serotype results using genetic and serologic methods were determined. Methods Genomic DNA from representative 11F-like S. pneumoniae isolates obtained from the nasopharynx of Fijian children was extracted and subject to whole genome sequencing. Genetic and phylogenetic analyses were used to identify genetic changes in the cps locus. Capsular phenotypes were evaluated using the Quellung reaction and latex agglutination. Results Compared to published 11F sequences, the wcwC and wcrL genes of the 11F-like cps locus are phylogenetically divergent, and the gct gene contains a single nucleotide insertion within a homopolymeric region. These changes within the DNA sequence of the 11F-like cps locus have modified the antigenic properties of the capsule, such that 11F-like isolates serotype as 11A by Quellung reaction and latex agglutination. Conclusions This study demonstrates the ability of molecular serotyping by microarray to identify genetic variants of S. pneumoniae and highlights the potential for discrepant results between phenotypic and genotypic serotyping methods. We propose that 11F-like isolates are not a new serotype but rather are a novel genetic variant of serotype 11A. These findings have implications for invasive pneumococcal disease surveillance as well as studies investigating vaccine impact.
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Affiliation(s)
- S Manna
- Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.
| | - B D Ortika
- Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - E M Dunne
- Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - K E Holt
- Centre for Systems Genomics, The University of Melbourne, Parkville, Victoria, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - M Kama
- Ministry of Health and Medical Services, Suva, Fiji
| | - F M Russell
- Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia; Centre for International Child Health, Murdoch Childrens Research Institute, Melbourne, Australia
| | - J Hinds
- Institute for Infection and Immunity, St. George's, University of London, United Kingdom; BUGS Bioscience, London Bioscience Innovation Centre, London, United Kingdom
| | - C Satzke
- Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia; Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, Victoria, Australia
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13
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Abstract
The capsular polysaccharide (CPS) is the major virulence factor of the emerging zoonotic pathogen Streptococcus suis. CPS differences are also the basis for serological differentiation of the species into 29 serotypes. Serotypes 2 and 1/2, which possess identical gene content in their cps loci, express CPSs that differ only by substitution of galactose (Gal) by N-acetylgalactosamine (GalNAc) in the CPS side chain. The same sugar substitution differentiates the CPS of serotypes 14 and 1, whose cps loci are also identical in gene content. Here, using mutagenesis, CPS structural analysis, and protein structure modeling, we report that a single amino acid polymorphism in the glycosyltransferase CpsK defines the enzyme substrate predilection for Gal or GalNAc and therefore determines CPS composition, structure, and strain serotype. We also show that the different CPS structures have similar antiphagocytic properties and that serotype switching has limited impact on the virulence of S. suis.
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14
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Position of O-Acetylation within the Capsular Repeat Unit Impacts the Biological Properties of Pneumococcal Serotypes 33A and 33F. Infect Immun 2017; 85:IAI.00132-17. [PMID: 28438972 DOI: 10.1128/iai.00132-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/13/2017] [Indexed: 12/26/2022] Open
Abstract
Streptococcus pneumoniae (pneumococcus) produces many capsule types that differ in their abilities to evade host immune recognition. To explain these serotype-dependent protective capacities, many studies have investigated capsular thickness or the interaction of the capsule with complement proteins, but the effects of small chemical modifications of the capsule on its function have not been studied. One small chemical modification found frequently among pneumococcal capsules is O-acetylation. Pneumococcal serotype 33A has two membrane-bound O-acetyltransferase genes, wciG and wcjE A 33A wcjE-deficient variant, 33F, occurs naturally and is increasing in prevalence in the wake of widespread conjugate vaccine use, but no wciG-deficient variants have been reported. To study the biological consequence of the loss of O-acetylation, we created wciG-deficient variants in both serotypes 33A and 33F, which we named 33X1 (ΔwciG) and 33X2 (ΔwciG ΔwcjE). Serotypes 33X1 and 33X2 express novel capsule types based on serological and biochemical analyses. We found that loss of WcjE-mediated O-acetylation appears not to affect cell wall shielding, since serotypes 33A and 33F exhibit comparable nonspecific opsonophagocytic killing, biofilm production, and adhesion to nasopharyngeal cells, though serotype 33F survived short-term drying better than serotype 33A. Loss of WciG-mediated O-acetylation in serotypes 33X1 and 33X2, however, resulted in a phenotype resembling that of nonencapsulated strains: increased cell wall accessibility, increased nonspecific opsonophagocytic killing, enhanced biofilm formation, and increased adhesion to nasopharyngeal cells. We conclude that WciG-mediated, but not WcjE-mediated, O-acetylation is important for producing protective capsules in 33A and that small chemical changes to the capsule can drastically affect its biological properties.
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15
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Polysaccharide Capsule Composition of Pneumococcal Serotype 19A Subtypes Is Unaltered among Subtypes and Independent of the Nutritional Environment. Infect Immun 2016; 84:3152-3160. [PMID: 27550933 DOI: 10.1128/iai.00474-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/12/2016] [Indexed: 11/20/2022] Open
Abstract
Serotype 19A strains have emerged as a cause of invasive pneumococcal disease after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7), and serotype 19A has now been included in the recent 13-valent vaccine (PCV13). Genetic analysis has revealed at least three different capsular serotype 19A subtypes, and nutritional environment-dependent variation of the 19A capsule structure has been reported. Pneumococcal vaccine effectiveness and serotyping accuracy might be impaired by structural differences in serotype 19A capsules. We therefore analyzed the distribution of 19A subtypes collected within a Swiss national surveillance program and determined capsule composition under different nutritional conditions with high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. After the introduction of PCV7, a significant relative increase of subtype 19A-II and decrease of 19A-I occurred. Chemical analyses showed no difference in the composition as well as the linkage of 19A subtype capsular saccharides grown in defined and undefined growth media, which is consistent with a trisaccharide repeat unit composed of rhamnose, N-acetyl-mannosamine, and glucose. In summary, our study suggests that no structural variance dependent of the nutritional environment or the subtype exists. The serotype 19A subtype shift observed after the introduction of the PCV7 can therefore not be explained by selection of a capsule structure variant. However, capsule composition analysis of emerging 19A clones is recommended in cases where there is no other explanation for a selective advantage, such as antibiotic resistance or loss or acquisition of other virulence factors.
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16
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Kapatai G, Sheppard CL, Al-Shahib A, Litt DJ, Underwood AP, Harrison TG, Fry NK. Whole genome sequencing of Streptococcus pneumoniae: development, evaluation and verification of targets for serogroup and serotype prediction using an automated pipeline. PeerJ 2016; 4:e2477. [PMID: 27672516 PMCID: PMC5028725 DOI: 10.7717/peerj.2477] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/23/2016] [Indexed: 11/25/2022] Open
Abstract
Streptococcus pneumoniae typically express one of 92 serologically distinct capsule polysaccharide (cps) types (serotypes). Some of these serotypes are closely related to each other; using the commercially available typing antisera, these are assigned to common serogroups containing types that show cross-reactivity. In this serotyping scheme, factor antisera are used to allocate serotypes within a serogroup, based on patterns of reactions. This serotyping method is technically demanding, requires considerable experience and the reading of the results can be subjective. This study describes the analysis of the S. pneumoniae capsular operon genetic sequence to determine serotype distinguishing features and the development, evaluation and verification of an automated whole genome sequence (WGS)-based serotyping bioinformatics tool, PneumoCaT (Pneumococcal Capsule Typing). Initially, WGS data from 871 S. pneumoniae isolates were mapped to reference cps locus sequences for the 92 serotypes. Thirty-two of 92 serotypes could be unambiguously identified based on sequence similarities within the cps operon. The remaining 60 were allocated to one of 20 ‘genogroups’ that broadly correspond to the immunologically defined serogroups. By comparing the cps reference sequences for each genogroup, unique molecular differences were determined for serotypes within 18 of the 20 genogroups and verified using the set of 871 isolates. This information was used to design a decision-tree style algorithm within the PneumoCaT bioinformatics tool to predict to serotype level for 89/94 (92 + 2 molecular types/subtypes) from WGS data and to serogroup level for serogroups 24 and 32, which currently comprise 2.1% of UK referred, invasive isolates submitted to the National Reference Laboratory (NRL), Public Health England (June 2014–July 2015). PneumoCaT was evaluated with an internal validation set of 2065 UK isolates covering 72/92 serotypes, including 19 non-typeable isolates and an external validation set of 2964 isolates from Thailand (n = 2,531), USA (n = 181) and Iceland (n = 252). PneumoCaT was able to predict serotype in 99.1% of the typeable UK isolates and in 99.0% of the non-UK isolates. Concordance was evaluated in UK isolates where further investigation was possible; in 91.5% of the cases the predicted capsular type was concordant with the serologically derived serotype. Following retesting, concordance increased to 99.3% and in most resolved cases (97.8%; 135/138) discordance was shown to be caused by errors in original serotyping. Replicate testing demonstrated that PneumoCaT gave 100% reproducibility of the predicted serotype result. In summary, we have developed a WGS-based serotyping method that can predict capsular type to serotype level for 89/94 serotypes and to serogroup level for the remaining four. This approach could be integrated into routine typing workflows in reference laboratories, reducing the need for phenotypic immunological testing.
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Affiliation(s)
- Georgia Kapatai
- Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom
| | - Carmen L Sheppard
- Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom
| | - Ali Al-Shahib
- Infectious Disease Informatics, Public Health England, London, United Kingdom
| | - David J Litt
- Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom
| | - Anthony P Underwood
- Infectious Disease Informatics, Public Health England, London, United Kingdom
| | - Timothy G Harrison
- Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom
| | - Norman K Fry
- Respiratory and Vaccine Preventable Bacterial Reference Unit, Public Health England, London, United Kingdom
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17
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Pneumococcus with the "6E" cps Locus Produces Serotype 6B Capsular Polysaccharide. J Clin Microbiol 2016; 54:967-71. [PMID: 26818670 DOI: 10.1128/jcm.03194-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 01/15/2016] [Indexed: 11/20/2022] Open
Abstract
Genetic studies of serogroup 6 isolates ofStreptococcus pneumoniaeidentified putative serotype 6E. Although its capsular polysaccharide structure has not been elucidated, putative serotype 6E is described in an increasing number of studies as a potentially new serotype. We show here that SPEC6B, which is widely used as a target strain for serotype 6B opsonophagocytosis assays, has the genetic features of the putative serotype 6E but produces capsular polysaccharide identical to 6B capsular polysaccharide as determined by one-dimensional (1D) and 2D nuclear magnetic resonance (NMR). Thus, putative serotype 6E is a mere genetic variant of serotype 6B. Also, SPEC6B is appropriate as a target strain for serotype 6B opsonophagocytosis assays. This example illustrates the difficulties of assigning new bacterial serotypes based on genetic findings alone.
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18
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Abstract
Streptococcus pneumoniae (the pneumococcus) is an important human pathogen. Its virulence is largely due to its polysaccharide capsule, which shields it from the host immune system, and because of this, the capsule has been extensively studied. Studies of the capsule led to the identification of DNA as the genetic material, identification of many different capsular serotypes, and identification of the serotype-specific nature of protection by adaptive immunity. Recent studies have led to the determination of capsular polysaccharide structures for many serotypes using advanced analytical technologies, complete elucidation of genetic basis for the capsular types, and the development of highly effective pneumococcal conjugate vaccines. Conjugate vaccine use has altered the serotype distribution by either serotype replacement or switching, and this has increased the need to serotype pneumococci. Due to great advances in molecular technologies and our understanding of the pneumococcal genome, molecular approaches have become powerful tools to predict pneumococcal serotypes. In addition, more-precise and -efficient serotyping methods that directly detect polysaccharide structures are emerging. These improvements in our capabilities will greatly enhance future investigations of pneumococcal epidemiology and diseases and the biology of colonization and innate immunity to pneumococcal capsules.
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19
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Gladstone RA, Jefferies JM, Tocheva AS, Beard KR, Garley D, Chong WW, Bentley SD, Faust SN, Clarke SC. Five winters of pneumococcal serotype replacement in UK carriage following PCV introduction. Vaccine 2015; 33:2015-21. [PMID: 25776920 PMCID: PMC4392391 DOI: 10.1016/j.vaccine.2015.03.012] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 12/02/2022]
Abstract
PCV7 serotype replacement was near complete 5 years after PCV7 introduction. The carriage rate remained stable through out the 5 year period. Serotypes unique to PCV13 significantly decreased by the final winter. Clonal expansion of existing genotypes was primarily responsible for replacement. Continued surveillance is needed to monitor replacement until equilibrium is reached.
The seven-valent pneumococcal conjugate vaccine (PCV7) was added to the UK national immunisation programme in September 2006. PCV13 replaced PCV7 in April 2010. As carriage precedes disease cases this study collected carried pneumococci from children each winter from 2006/7 to 2010/11 over PCV introduction. Conventional microbiology and whole genome sequencing were utilised to characterise pneumococcal strains. Overall prevalence of pneumococcal carriage remained stable. Vaccine serotypes (VT) decreased (p < 0.0001) with concomitant increases in non-vaccine serotypes (NVT). In winter 2010/11 only one isolate of PCV7 VT was observed (6B). PCV13 unique VTs decreased between winters immediately preceding and following PCV13 introduction (p = 0.04). Significant decreases for VTs 6B, 19F, 23F (PCV7) and 6A (PCV13) and increases for NVT 21, 23B, 33F and 35F were detected. The serotype replacement was accompanied by parallel changes in genotype prevalence for associated sequence types with clonal expansion contributing to replacement. By winter 2010/11, serotype coverage of PCV7 and PCV13 was 1% and 11% respectively. VT replacement was observed for PCV7 and PCV13 serotypes. Conjugate vaccine design and use requires continuous monitoring and revision.
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Affiliation(s)
- Rebecca A Gladstone
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, UK
| | - Johanna M Jefferies
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, UK; Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton Foundation NHS Trust, Southampton, UK
| | - Anna S Tocheva
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, UK
| | - Kate R Beard
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, UK
| | - David Garley
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, UK
| | - Wei Wei Chong
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, UK
| | | | - Saul N Faust
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, UK; Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton Foundation NHS Trust, Southampton, UK; NIHR Wellcome Trust Clinical Research Facility, University Hospital Southampton Foundation NHS Trust, Southampton, UK
| | - Stuart C Clarke
- Faculty of Medicine and Institute for Life Sciences, University of Southampton, UK; Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton Foundation NHS Trust, Southampton, UK.
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20
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Genetic, biochemical, and serological characterization of a new pneumococcal serotype, 6H, and generation of a pneumococcal strain producing three different capsular repeat units. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:313-8. [PMID: 25589550 DOI: 10.1128/cvi.00647-14] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Streptococcus pneumoniae clinical isolates were recently described that produced capsular polysaccharide with properties of both serotypes 6A and 6B. Their hybrid serological property correlated with mutations affecting the glycosyltransferase WciP, which links rhamnose to ribitol by an α(1-3) linkage for serotypes 6A and 6C and an α(1-4) linkage for serotypes 6B and 6D. The isolates had mutations in the triad residues of WciP that have been correlated with enzyme specificity. The canonical triad residues of WciP are Ala192-Ser195-Arg254 for serotypes 6A and 6C and Ser192-Asn195-Gly254 for serotypes 6B and 6D. To prove that the mutations in the triad residues are responsible for the hybrid serotype, we introduced the previously described Ala192-Cys195-Arg254 triad into a 6A strain and found that the change made WciP bispecific, resulting in 6A and 6B repeat unit expression, although 6B repeat unit production was favored over production of 6A repeat units. Likewise, this triad permitted a 6C strain to express 6C and 6D repeat units. With reported bispecificity in WciN, which adds either glucose or galactose as the second sugar in the serogroup 6 repeat unit, the possibility exists for a strain to simultaneously produce all four serogroup 6 repeat units; however, when genes encoding both bispecific enzymes were introduced into a 6A strain, only 6A, 6B, and 6D repeat units were detected serologically. Nonetheless, this may be the first example of a bacterial polysaccharide with three different repeat units. This strategy of expressing multiple repeat units in a single polymer is a novel approach to broadening vaccine coverage by eliminating the need for multiple polysaccharide sources to cover multiple serogroup members.
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21
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Lv G, Hu D, Zhao J, Li S. Quality control of sweet medicines based on gas chromatography-mass spectrometry. Drug Discov Ther 2015; 9:94-106. [DOI: 10.5582/ddt.2015.01020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Guangping Lv
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau
| | - Dejun Hu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau
| | - Jing Zhao
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau
| | - Shaoping Li
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau
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22
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Abstract
Gram-positive organisms, including the pathogens Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecalis, have dynamic cell envelopes that mediate interactions with the environment and serve as the first line of defense against toxic molecules. Major components of the cell envelope include peptidoglycan (PG), which is a well-established target for antibiotics, teichoic acids (TAs), capsular polysaccharides (CPS), surface proteins, and phospholipids. These components can undergo modification to promote pathogenesis, decrease susceptibility to antibiotics and host immune defenses, and enhance survival in hostile environments. This chapter will cover the structure, biosynthesis, and important functions of major cell envelope components in gram-positive bacteria. Possible targets for new antimicrobials will be noted.
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23
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Brady AM, Calix JJ, Yu J, Geno KA, Cutter GR, Nahm MH. Low invasiveness of pneumococcal serotype 11A is linked to ficolin-2 recognition of O-acetylated capsule epitopes and lectin complement pathway activation. J Infect Dis 2014; 210:1155-65. [PMID: 24683196 PMCID: PMC4215079 DOI: 10.1093/infdis/jiu195] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/18/2014] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The divergent epidemiological behavior of Streptococcus pneumoniae serotypes suggests that serotype-specific features such as capsule O-acetylation influence the propensity of a strain to cause invasive pneumococcal disease (IPD). We hypothesize that innate host factors mediate the observed negative association between IPD and the serotype 11A (ST11A) capsule O-acetyltransferase gene, wcjE. METHODS We evaluated the ability of ficolin-2, an initiator of the lectin complement pathway that was previously shown to bind ST11A pneumococci, to recognize and mediate complement-dependent opsonophagocytosis of different pneumococcal serotypes. We supplemented findings with an epidemiological meta-analysis comparing invasiveness of the 30 most prevalent pneumococcal serotypes. RESULTS Ficolin-2 bound ST11A capsule polysaccharide and other wcjE-containing pneumococcal serotypes, except ST9V and ST20B. Ficolin-2 did not bind wcjE-null serotypes, including the wcjE-null variant of ST11A, ST11E. We observed C1q-independent complement deposition and phagocytic killing of pneumococci expressing ST11A but not those expressing ST11E. Inhibition of ficolin-2 binding abrogated ST11A-associated complement deposition and phagocytosis. In children, invasiveness of ST11A was the lowest among serotypes tested in our meta-analysis, while ST9V was among the highest. CONCLUSIONS Ficolin-2 mediates serum protection by recognizing specific O-acetylated epitopes of pneumococcal capsule polysaccharides, exemplifying a novel host-microbe interaction that innately offers serotype-specific immunity to IPD.
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Affiliation(s)
| | | | | | | | - Gary R. Cutter
- School of Public Health, University of Alabama at Birmingham
| | - Moon H. Nahm
- Department of Pathology
- Department of Microbiology
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24
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Børud B, Anonsen JH, Viburiene R, Cohen EH, Samuelsen ABC, Koomey M. Extended glycan diversity in a bacterial protein glycosylation system linked to allelic polymorphisms and minimal genetic alterations in a glycosyltransferase gene. Mol Microbiol 2014; 94:688-99. [PMID: 25213144 DOI: 10.1111/mmi.12789] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2014] [Indexed: 12/17/2022]
Abstract
Glycans manifest in conjunction with the broad spectrum O-linked protein glycosylation in species within the genus Neisseria display intra- and interstrain diversity. Variability in glycan structure and antigenicity are attributable to differences in the content and expression status of glycan synthesis genes. Given the high degree of standing allelic polymorphisms in these genes, the level of glycan diversity may exceed that currently defined. Here, we identify unique protein-associated disaccharide glycoforms that carry N-acetylglucosamine (GlcNAc) at their non-reducing end. This altered structure was correlated with allelic variants of pglH whose product was previously demonstrated to be responsible for the expression of glucose (Glc)-containing disaccharides. Allele comparisons and site-specific mutagenesis showed that the presence of a single residue, alanine at position 303 in place of a glutamine, was sufficient for GlcNAc versus Glc incorporation. Phylogenetic analyses revealed that GlcNAc-containing disaccharides may be widely distributed within the pgl systems of Neisseria particularly in strains of N. meningitidis. Although analogous minimal structural alterations in glycosyltransferases have been documented in association with lipopolysaccharide and capsular polysaccharide variability, this appears to be the first example in which such changes have been implicated in glycan diversification within a bacterial protein glycosylation system.
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Affiliation(s)
- Bente Børud
- Department of Biosciences, University of Oslo, Oslo, Norway
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Camilli R, Spencer BL, Moschioni M, Pinto V, Berti F, Nahm MH, Pantosti A. Identification of Streptococcus pneumoniae serotype 11E, serovariant 11Av and mixed populations by high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy and flow cytometric serotyping assay (FCSA). PLoS One 2014; 9:e100722. [PMID: 24967818 PMCID: PMC4072641 DOI: 10.1371/journal.pone.0100722] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/28/2014] [Indexed: 11/18/2022] Open
Abstract
Background Recent studies have identified Streptococcus pneumoniae serotype 11E and serovariant 11Av among isolates previously typed as 11A by classical serotyping methods. Serotype 11E and serovariant 11Av differ from serotype 11A by having totally or partially inactive wcjE, a gene in cps locus coding for an O-acetyl transferase. Serotype 11E is rare among carriage isolates but common among invasive isolates suggesting that it survives better during invasion. Aim of this work was to investigate the epidemiology of serotype 11A in a pneumococcal collection using a new serotyping approach based on High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HR-MAS NMR) spectroscopy to distinguish serotypes 11A and 11E. Methods A collection of 48 (34 invasive and 14 carriage) S. pneumoniae isolates from Italy, previously identified as serotype 11A by the Quellung reaction, were investigated by wcjE sequencing, HR-MAS NMR spectroscopy and the reference flow cytometric serotyping assay (FCSA) based on monoclonal antibodies. Results HR-MAS NMR spectra from serotypes 11A and 11E showed different NMR peaks indicating that HR-MAS NMR could be used to distinguish these serotypes, although HR-MAS NMR could not distinguish serotype 11Av from serotype 11E unambiguously. Thirty-eight isolates were confirmed to be serotype 11A, 8 isolates with a mutated wcjE were serotype 11E, 1 isolate belonged to serovariant 11Av, and 1 isolate was a mixed population 11A/11Av. All 11E isolates were identified among invasive isolates. Conclusions We proved that HR-MAS NMR can be of potential use for pneumococcal serotyping. The detection of serotype 11E among invasive isolates in our collection, supports previous epidemiological studies suggesting that mutations in wcjE can represent a mechanism promoting pneumococcal survival during invasion. The discovery of a spectrum of immunochemical diversity within established serotypes should stimulate efforts to develop new serotyping approaches.
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Affiliation(s)
- Romina Camilli
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Brady L. Spencer
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | | | | | | | - Moon H. Nahm
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Annalisa Pantosti
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
- * E-mail:
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Lee LH, Gu XX, Nahm MH. Towards New Broader Spectrum Pneumococcal Vaccines: The Future of Pneumococcal Disease Prevention. Vaccines (Basel) 2014; 2:112-28. [PMID: 26344470 PMCID: PMC4494192 DOI: 10.3390/vaccines2010112] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/18/2014] [Accepted: 02/06/2014] [Indexed: 01/13/2023] Open
Abstract
Seven-valent pneumococcal conjugate vaccine (PCV7) introduction and routine pediatric use has substantially reduced the burden of Streptococcus pneumoniae disease worldwide. However, a significant amount of disease burden, due to serotypes not contained in PCV7, still exists globally. A newly recognized serotype, 6C, was until recently, identified and reported as serotype 6A. This review summarizes the serotype epidemiology of pneumococcal disease pre- and post-introduction of PCV7, available post-marketing surveillance data following the introduction of higher valency pneumococcal vaccines (PCV10, PCV13) and future prospects for the development of new pneumococcal vaccines.
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Affiliation(s)
- Lucia H Lee
- Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, MD 20852, USA.
| | - Xin-Xing Gu
- National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA.
| | - Moon H Nahm
- Departments of Microbiology and Pathology, University of Alabama at Birmingham, Birmingham, AL 35233, USA.
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Domenech M, Araújo-Bazán L, García E, Moscoso M. In vitro biofilm formation by Streptococcus pneumoniae as a predictor of post-vaccination emerging serotypes colonizing the human nasopharynx. Environ Microbiol 2014; 16:1193-201. [PMID: 24373136 DOI: 10.1111/1462-2920.12370] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 12/14/2013] [Indexed: 11/29/2022]
Abstract
The increasing use of the 7-valent pneumococcal conjugate vaccine has been accompanied by the rise of non-vaccine serotypes colonizing the human nasopharynx. The vast majority of infections are caused by microorganisms that grow in biofilms. It has recently been shown that the formation of Streptococcus pneumoniae biofilms in vivo and in vitro is hindered by the presence of capsular polysaccharide. The biofilm-forming capacity of pneumococcal clinical isolates with different types of capsular polysaccharide and various isogenic transformants was examined. Strains of serotypes 19A and 19F, but not 19B and 19C, formed ≥ 80% of the quantity of biofilm associated with a non-encapsulated control strain. Strains of serogroup 6 also showed significant biofilm-forming capacity. The capsules of serotypes 19A and 19F, and serogroup 6 contain the disaccharides α-D-Glcp-(1→2)-α-L-Rhap-(1→ and α-D-Glcp-(1→3)-α-L-Rhap-(1→. Serotype 18A and serotypes 18B/18C have very similar capsular disaccharides: α-D-GlcpNAc-(1→3)-β-L-Rhap-(1→ and α-D-Glcp-(1→3)-β-L-Rhap-(1→ respectively. However, the strains of serogroup 18 showed impaired biofilm formation. These results indicate that the chemical composition/structure of the capsular polysaccharide is crucial to the biofilm-forming capacity of pneumococcal serotypes. Testing of the in vitro biofilm-forming ability of isogenic transformants expressing different capsular polysaccharides may help predict the emergence of colonizing, non-vaccine serotypes.
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Affiliation(s)
- Mirian Domenech
- Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (CIB-CSIC), Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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Spectrum of pneumococcal serotype 11A variants results from incomplete loss of capsule O-acetylation. J Clin Microbiol 2013; 52:758-65. [PMID: 24352997 DOI: 10.1128/jcm.02695-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae is a significant bacterial pathogen that expresses >90 capsule serotypes. Conventional serotyping methods assume that each serotype is a genetically and antigenically distinct entity; however, recent investigations have revealed pneumococcal isolates that cannot be unambiguously serotyped because they share the properties of more than one serotype. Here, we employed a novel serotyping method and NMR spectroscopy to examine clinical isolates sharing properties of serotypes 11A and 11E. These ambiguous clinical isolates were provisionally named 11A variant (11Av) isolates. Serotype 11A pneumococci characteristically express capsule β-galactose-6-O-acetylation (βGal6OAc) mediated by the capsule synthesis gene wcjE, while 11E strains contain loss-of-function mutations in wcjE and completely lack the expression of βGal6OAc. Although 11Av isolates also contained mutated wcjE alleles, 11Av clinical isolates were composed of antigenically homogeneous bacteria expressing reduced amounts of 11A-specific capsule antigen. NMR data confirmed reduced but detectable amounts of βGal6OAc on 11Av capsule polysaccharide. Furthermore, the transformation of strains with wcjE alleles from 11Av strains was sufficient to restore partial βGal6OAc in an 11E background. We conclude that, instead of being distinct entities, serotypes 11A and 11E represent two extremes of an antigenic spectrum resulting from variable capsule O-acetylation secondary to heterologous wcjE mutations. These findings challenge whether all clinically relevant pneumococci can be definitively categorized into distinct serotypes.
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