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Mettu R, Cheng YY, Vulupala HR, Lih YH, Chen CY, Hsu MH, Lo HJ, Liao KS, Chiu CH, Wu CY. Chemical Synthesis of Truncated Capsular Oligosaccharide of Serotypes 6C and 6D of Streptococcus pneumoniae with Their Immunological Studies. ACS Infect Dis 2024; 10:2161-2171. [PMID: 38770797 DOI: 10.1021/acsinfecdis.4c00147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Serotypes 6C and 6D of Streptococcus pneumoniae are two major variants that cause invasive pneumococcal disease (IPD) in serogroup 6 alongside serotypes 6A and 6B. Since the introduction of the pneumococcal conjugate vaccines PCV7 and PCV13, the number of cases of IPD caused by pneumococcus in children and the elderly population has greatly decreased. However, with the widespread use of vaccines, a replacement effect has recently been observed among different serotypes and lowered the effectiveness of the vaccines. To investigate protection against the original serotypes and to explore protection against variants and replacement serotypes, we created a library of oligosaccharide fragments derived from the repeating units of the capsular polysaccharides of serotypes 6A, 6B, 6C, and 6D through chemical synthesis. The library includes nine pseudosaccharides with or without exposed terminal phosphate groups and four pseudotetrasaccharides bridged by phosphate groups. Six carbohydrate antigens related to 6C and 6D were prepared as glycoprotein vaccines for immunogenicity studies. Two 6A and two 6B glycoconjugate vaccines from previous studies were included in immunogenicity studies. We found that the conjugates containing four phosphate-bridged pseudotetrasaccharides were able to induce good immune antibodies and cross-immunogenicity by showing superior activity and broad cross-protective activity in OPKA bactericidal experiments.
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Affiliation(s)
- Ravinder Mettu
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Yang-Yu Cheng
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, No. 155, Section 2, Linong Street, Taipei 112304, Taiwan
| | - Hanmanth Reddy Vulupala
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Yu-Hsuan Lih
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Chiang-Yun Chen
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Mei-Hua Hsu
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 259 Wenhua First Road, Guishan, Taoyuan 33302, Taiwan
| | - Hong-Jay Lo
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Kuo-Shiang Liao
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Cheng-Hsun Chiu
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 259 Wenhua First Road, Guishan, Taoyuan 33302, Taiwan
| | - Chung-Yi Wu
- Genomics Research Center, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
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2
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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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Abdul Rahman NA, Mohd Desa MN, Masri SN, Taib NM, Sulaiman N, Hazman H, John J. The Molecular Approaches and Challenges of Streptococcus pneumoniae Serotyping for Epidemiological Surveillance in the Vaccine Era. Pol J Microbiol 2023; 72:103-115. [PMID: 37314355 DOI: 10.33073/pjm-2023-023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/09/2023] [Indexed: 06/15/2023] Open
Abstract
Streptococcus pneumoniae (pneumococcus) belongs to the Gram-positive cocci. This bacterium typically colonizes the nasopharyngeal region of healthy individuals. It has a distinct polysaccharide capsule - a virulence factor allowing the bacteria to elude the immune defense mechanisms. Consequently, it might trigger aggressive conditions like septicemia and meningitis in immunocompromised or older individuals. Moreover, children below five years of age are at risk of morbidity and mortality. Studies have found 101 S. pneumoniae capsular serotypes, of which several correlate with clinical and carriage isolates with distinct disease aggressiveness. Introducing pneumococcal conjugate vaccines (PCV) targets the most common disease-associated serotypes. Nevertheless, vaccine selection pressure leads to replacing the formerly dominant vaccine serotypes (VTs) by non-vaccine types (NVTs). Therefore, serotyping must be conducted for epidemiological surveillance and vaccine assessment. Serotyping can be performed using numerous techniques, either by the conventional antisera-based (Quellung and latex agglutination) or molecular-based approaches (sequetyping, multiplex PCR, real-time PCR, and PCR-RFLP). A cost-effective and practical approach must be used to enhance serotyping accuracy to monitor the prevalence of VTs and NVTs. Therefore, dependable pneumococcal serotyping techniques are essential to precisely monitor virulent lineages, NVT emergence, and genetic associations of isolates. This review discusses the principles, associated benefits, and drawbacks of the respective available conventional and molecular approaches, and potentially the whole genome sequencing (WGS) to be directed for future exploration.
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Affiliation(s)
- Nurul Asyikin Abdul Rahman
- 1Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
- 2School of Biology, Faculty of Applied Sciences, Universiti Teknologi MARA, Kuala Pilah, Malaysia
| | - Mohd Nasir Mohd Desa
- 1Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Siti Norbaya Masri
- 3Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Niazlin Mohd Taib
- 3Department of Medical Microbiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Nurshahira Sulaiman
- 1Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Hazmin Hazman
- 1Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - James John
- 4Department of Medical Laboratory Technology, School of Allied Health Science, Sathyabama Institute of Science and Technology, Chennai, India
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5
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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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6
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Downs SL, Madhi SA, van der Merwe L, Nunes MC, Olwagen CP. Optimization of a high-throughput nanofluidic real-time PCR to detect and quantify of 15 bacterial species and 92 Streptococcus pneumoniae serotypes. Sci Rep 2023; 13:4588. [PMID: 36944704 PMCID: PMC10030628 DOI: 10.1038/s41598-023-31820-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 03/17/2023] [Indexed: 03/23/2023] Open
Abstract
Sensitive tools for detecting concurrent colonizing pneumococcal serotypes are needed for detailed evaluation of the direct and indirect impact of routine pneumococcal conjugate vaccine (PCV) immunization. A high-throughput quantitative nanofluidic real-time PCR (Standard BioTools 'Fluidigm') reaction-set was developed to detect and quantify 92 pneumococcal serotypes in archived clinical samples. Nasopharyngeal swabs collected in 2009-2011 from South African children ≤ 5 years-old, previously serotyped with standard culture-based methods were used for comparison. The reaction-set within the 'Fluidigm' effectively amplified all targets with high efficiency (90-110%), reproducibility (R2 ≥ 0.98), and at low limit-of-detection (< 102 CFU/ml). A blind analysis of 1 973 nasopharyngeal swab samples showed diagnostic sensitivity > 80% and specificity > 95% compared with the referent standard, culture based Quellung method. The qPCR method was able to serotype pneumococcal types with good discrimination compared with Quellung (ROC-AUC: > 0.73). The high-throughput nanofluidic real-time PCR method simultaneously detects 57 individual serotypes, and 35 serotypes within 16 serogroups in 96 samples (including controls), within a single qPCR run. This method can be used to evaluate the impact of current PCV formulations on vaccine-serotype and non-vaccine-serotype colonization, including detection of multiple concurrently colonizing serotypes. Our qPCR method can allow for monitoring of serotype-specific bacterial load, as well as emergence or ongoing transmission of minor or co-colonizing serotypes that may have invasive disease potential.
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Affiliation(s)
- Sarah L Downs
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
- Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Shabir A Madhi
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lara van der Merwe
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Marta C Nunes
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Courtney P Olwagen
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
- Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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7
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Gong W, Liang M, Zhao J, Wang H, Chen Z, Wang F, Gu G. Biochemical Characterization and Synthetic Application of WciN and Its Mutants From Streptococcus pneumoniae Serotype 6B. Front Chem 2022; 10:914698. [PMID: 35783203 PMCID: PMC9240355 DOI: 10.3389/fchem.2022.914698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/02/2022] [Indexed: 12/02/2022] Open
Abstract
The biochemical properties of α-1,3-galactosyltransferase WciN from Streptococcus pneumoniae serotype 6B were systemically characterized with the chemically synthesized Glcα-PP-(CH2)11-OPh as an acceptor substrate. The in vitro site-directed mutation of D38 and A150 residues of WciN was further investigated, and the enzymatic activities of those WciN mutants revealed that A150 residue was the pivotal residue responsible for nucleotide donor recognition and the single-site mutation could completely cause pneumococcus serotype switch. Using WciNA150P and WciNA150D mutants as useful tool enzymes, the disaccharides Galα1,3Glcα-PP-(CH2)11-OPh and Glcα1,3Glcα-PP-(CH2)11-OPh were successfully prepared in multi-milligram scale in high yields.
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Affiliation(s)
- Wei Gong
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
- School of Pharmaceutical Science, Shandong University, Jinan, China
| | - Min Liang
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
- NMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate-based Medicine, Shandong University, Qingdao, China
| | - Jielin Zhao
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
- NMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate-based Medicine, Shandong University, Qingdao, China
| | - Hong Wang
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
- NMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate-based Medicine, Shandong University, Qingdao, China
| | - Zonggang Chen
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
- NMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate-based Medicine, Shandong University, Qingdao, China
| | - Fengshan Wang
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
- School of Pharmaceutical Science, Shandong University, Jinan, China
- NMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate-based Medicine, Shandong University, Qingdao, China
| | - Guofeng Gu
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Qingdao, China
- NMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate-based Medicine, Shandong University, Qingdao, China
- *Correspondence: Guofeng Gu,
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8
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An H, Qian C, Huang Y, Li J, Tian X, Feng J, Hu J, Fang Y, Jiao F, Zeng Y, Huang X, Meng X, Liu X, Lin X, Zeng Z, Guilliams M, Beschin A, Chen Y, Wu Y, Wang J, Oggioni MR, Leong J, Veening JW, Deng H, Zhang R, Wang H, Wu J, Cui Y, Zhang JR. Functional vulnerability of liver macrophages to capsules defines virulence of blood-borne bacteria. J Exp Med 2022; 219:213054. [PMID: 35258552 PMCID: PMC8908791 DOI: 10.1084/jem.20212032] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 12/22/2021] [Accepted: 01/24/2022] [Indexed: 12/12/2022] Open
Abstract
Many encapsulated bacteria use capsules to cause invasive diseases. However, it remains largely unknown how the capsules enhance bacterial virulence under in vivo infection conditions. Here we show that the capsules primarily target the liver to enhance bacterial survival at the onset of blood-borne infections. In a mouse sepsis model, the capsules enabled human pathogens Streptococcus pneumoniae and Escherichia coli to circumvent the recognition of liver-resident macrophage Kupffer cells (KCs) in a capsular serotype-dependent manner. In contrast to effective capture of acapsular bacteria by KCs, the encapsulated bacteria are partially (low-virulence types) or completely (high-virulence types) “untouchable” for KCs. We finally identified the asialoglycoprotein receptor (ASGR) as the first known capsule receptor on KCs to recognize the low-virulence serotype-7F and -14 pneumococcal capsules. Our data identify the molecular interplay between the capsules and KCs as a master controller of the fate and virulence of encapsulated bacteria, and suggest that the interplay is targetable for therapeutic control of septic infections.
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Affiliation(s)
- Haoran An
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Chenyun Qian
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Yijia Huang
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Jing Li
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Xianbin Tian
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Jiaying Feng
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Jiao Hu
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Yujie Fang
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Fangfang Jiao
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Yuna Zeng
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China
| | - Xueting Huang
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Xianbin Meng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Xue Liu
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Xin Lin
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
| | - Zhutian Zeng
- School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Martin Guilliams
- Laboratory of Myeloid Cell Biology in Tissue Homeostasis and Regeneration, VIB Center for Inflammation Research, Ghent, Belgium.,Department of Biomedical Molecular Biology, Faculty of Science, Ghent University, Ghent, Belgium
| | - Alain Beschin
- Myeloid Cell Immunology Lab, VIB Center for Inflammation Research, Brussels, Belgium.,Laboratory of Cellular and Molecular Immunology, Vrije University Brussel, Brussels, Belgium
| | - Yongwen Chen
- Institute of Immunology, Third Military Medical University, Chongqing, China
| | - Yuzhang Wu
- Institute of Immunology, Third Military Medical University, Chongqing, China
| | - Jing Wang
- Shanghai Institute of Immunology, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | | | - John Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Haiteng Deng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Rong Zhang
- The Second Affiliated Hospital of Zhejiang University, Zhejiang University, Hangzhou, China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Jiang Wu
- Beijing Center for Disease Control and Prevention, Beijing, China
| | - Yan Cui
- Department of General Surgery, Strategic Support Force Medical Center, Beijing, China
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China
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9
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Downs SL, Madhi SA, Van der Merwe L, Nunes MC, Olwagen CP. High-throughput nanofluidic real-time PCR to discriminate Pneumococcal Conjugate Vaccine (PCV)-associated serogroups 6, 18, and 22 to serotypes using modified oligonucleotides. Sci Rep 2021; 11:23728. [PMID: 34887480 PMCID: PMC8660885 DOI: 10.1038/s41598-021-03127-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 11/18/2021] [Indexed: 12/03/2022] Open
Abstract
Current real-time high-throughput Polymerase Chain Reaction (qPCR) methods do not distinguish serotypes 6A from 6B, 18C from 18A/B and 22F from 22A. We established a nanofluidic real-time PCR (Fluidigm) for serotyping that included Dual-Priming-Oligonucleotides (DPO), a Locked-Nucleic-Acid (LNA) probe and TaqMan assay-sets for high-throughput serotyping. The designed assay-sets target capsular gene wciP in serogroup 6, wciX and wxcM in serogroup 18, and wcwA in serogroup 22. An algorithm combining results from published assay-sets (6A/B/C/D; 6C/D; 18A/B/C; 22A/F) and designed assay-sets for 6A/C; 18B/C/F; 18C/F, 18F and 22F was validated through blind analysis of 1973 archived clinical samples collected from South African children ≤ 5-years-old (2009–2011), previously serotyped with the culture-based Quellung method. All assay-sets were efficient (92–101%), had low variation between replicates (R2 > 0.98), and were able to detect targets at a limit of detection (LOD) of < 100 Colony-Forming-Units (CFU)/mL of sample. There was high concordance (Kappa = 0.73–0.92); sensitivity (85–100%) and specificity (96–100%) for Fluidigm compared with Quellung for serotyping 6A; 6B; 6C; 18C and 22F. Fluidigm distinguishes vaccine-serotypes 6A, 6B, 18C, next-generation PCV-serotype 22F and non-vaccine-serotypes 6C, 6D, 18A, 18B, 18F and 22A. Discriminating single serotypes is important for assessing serotype replacement and the impact of PCVs on vaccine- and non-vaccine serotypes.
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Affiliation(s)
- S L Downs
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - S A Madhi
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - L Van der Merwe
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - M C Nunes
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - C P Olwagen
- South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Department of Science and Technology/National Research Foundation, South African Research Chair Initiative in Vaccine Preventable Diseases, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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10
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Takano C, Kuramochi Y, Seki M, Kim DW, Omagari D, Sasano M, Chang B, Ohnishi M, Kim EJ, Fuwa K, Kilgore PE, Hoshino T, Hayakawa S. Molecular serotype-specific identification of Streptococcus pneumoniae using loop-mediated isothermal amplification. Sci Rep 2019; 9:19823. [PMID: 31882619 PMCID: PMC6934563 DOI: 10.1038/s41598-019-56225-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 12/09/2019] [Indexed: 11/14/2022] Open
Abstract
In children, the incidence of pneumococcal meningitis has decreased since the introduction of pneumococcal conjugate vaccine (PCV7 and PCV13). However, since the introduction of the vaccine, developed countries have seen the emergence of non-PCV13 serotypes. However, invasive pneumococcal disease (IPD) caused by PCV13-targeted serotypes still represents an important public health problem in resource-limited countries. To develop a rapid, simple, and cost-effective assay to detect serotypes of Streptococcus pneumoniae, we developed a novel loop-mediated isothermal amplification (LAMP) assay based on the sequences available for the 13 capsular types that are included in PCV13: 1, 3, 4, 5, 6 A, 6B, 7 F, 9 V, 14, 18 C, 19 A, 19 F, and 23 F. We evaluated test reactivity, specificity, sensitivity and performance, and compared the results between established LAMP and conventional PCR assays. To support its clinical use, the detection limits of the LAMP assay were evaluated using bacterial genomic DNA-spiked cerebrospinal fluid (CSF) and blood specimens. We confirmed the specificity of the LAMP assay using 41 serotypes of pneumococcal strains. The sensitivity of the LAMP assay was 10 to 100 copies per reaction, compared to 10 to 104 copies per reaction for PCR assays. The detection limits of the LAMP assay were comparable when using DNA-spiked CSF and blood specimens, as compared to using purified DNA as the template. In conclusion, a rapid and simple LAMP-based pneumococcal serotyping method has been developed. This is the first report of a LAMP method for a PCV13 serotype-specific identification assay, which could be a promising step to facilitate epidemiological studies of pneumococcal serotyping.
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Affiliation(s)
- Chika Takano
- Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, 173-8610, Japan.,Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, 173-8610, Japan
| | - Yoko Kuramochi
- Nihon University School of Medicine, Tokyo, 173-8610, Japan
| | - Mitsuko Seki
- Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, 173-8610, Japan. .,Department of Pediatric Dentistry, School of Dentistry, Meikai University, Saitama, Japan.
| | - Dong Wook Kim
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, 15588, Republic of Korea. .,Institute of Pharmacological Research, Hanyang University, Ansan, 15588, Republic of Korea.
| | - Daisuke Omagari
- Nihon University School of Dentistry, Tokyo, 101-8310, Japan
| | - Mari Sasano
- Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, 173-8610, Japan.,Department of Neurological Surgery, Nihon University School of Medicine, Tokyo, 173-8610, Japan
| | - Bin Chang
- Bacteriology I, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | - Makoto Ohnishi
- Bacteriology I, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | - Eun Jin Kim
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, 15588, Republic of Korea.,Institute of Pharmacological Research, Hanyang University, Ansan, 15588, Republic of Korea
| | - Kazumasa Fuwa
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, 173-8610, Japan
| | - Paul E Kilgore
- Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy & Health Sciences, Wayne State University, Detroit, MI, 48201, USA
| | - Tomonori Hoshino
- Department of Pediatric Dentistry, School of Dentistry, Meikai University, Saitama, Japan
| | - Satoshi Hayakawa
- Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, 173-8610, Japan
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11
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Bojarska A, Janas K, Pejsak Z, Otulak-Kozieł K, Garbaczewska G, Hryniewicz W, Sadowy E. Diversity of serotypes and new cps loci variants among Streptococcus suis isolates from pigs in Poland and Belarus. Vet Microbiol 2019; 240:108534. [PMID: 31902504 DOI: 10.1016/j.vetmic.2019.108534] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 11/13/2019] [Accepted: 11/27/2019] [Indexed: 10/25/2022]
Abstract
Streptococcus suis plays an important role in infections in pigs but information about the epidemiology of this pathogen in Poland and Belarus remains scarce. Ninety-six isolates from brain and lungs were studied by PCR-based serotyping, analysis of virulence-associated determinants and multilocus sequence typing (MLST). Selected six isolates were further analyzed by genomic sequencing and transmission electron microscopy (TEM). Serotype 2 was most prevalent, followed by serotypes 3, 4, 8 and 7. All isolates carried fbpS; 30, 74 and 79 isolates were positive for epf, mrp and sao, respectively. MLST revealed that while widely distributed clonal complexes, such as 1, 16, 25 and 28 circulate in both countries, a significant part of the population is composed of novel singletons. Six isolates, all positive for the capsule in TEM, harbored cps loci differing to a various degree from these previously described, including one with a novel cps locus (putative NCL21). In conclusion, our study provides first molecular data on S. suis from pigs in the Central/Eastern Europe and contributes to a better characterization of diversity of loci responsible for capsule production in this pathogen.
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Affiliation(s)
- Agnieszka Bojarska
- Department of Molecular Microbiology, National Medicines Institute, Chełmska 30/34, 00-725 Warsaw, Poland
| | - Katarzyna Janas
- Department of Molecular Microbiology, National Medicines Institute, Chełmska 30/34, 00-725 Warsaw, Poland
| | - Zygmunt Pejsak
- Department of Swine Diseases, National Veterinary Research Institute, Al. Partyzantów 57, 24-100 Puławy, Poland
| | - Katarzyna Otulak-Kozieł
- Institute of Biology, Department of Botany, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland
| | - Grażyna Garbaczewska
- Institute of Biology, Department of Botany, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-766, Warsaw, Poland
| | - Waleria Hryniewicz
- Department of Epidemiology and Clinical Microbiology, National Medicines Institute, Chełmska 30/34, 00-725 Warsaw, Poland
| | - Ewa Sadowy
- Department of Molecular Microbiology, National Medicines Institute, Chełmska 30/34, 00-725 Warsaw, Poland.
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12
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Gonzales-Siles L, Salvà-Serra F, Degerman A, Nordén R, Lindh M, Skovbjerg S, Moore ERB. Identification and capsular serotype sequetyping of Streptococcus pneumoniae strains. J Med Microbiol 2019; 68:1173-1188. [PMID: 31268417 DOI: 10.1099/jmm.0.001022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Correct serotype identification of Streptococcus pneumoniae (pneumococcus) is important for monitoring disease epidemiology and assessing the impacts of pneumococcal vaccines. Furthermore, correct identification and differentiation of the pathogenic S. pneumoniae from closely related commensal species of the mitis group of the genus Streptococcus are essential for correct serotype identification. METHODOLOGY A new protocol for determining the existing 98 serotypes of pneumococcus was developed, applying two PCR amplifications and amplicon sequencing, using newly designed internal primers. The new protocol was validated using S. pneumoniae genome sequences, reference strains with confirmed serotypes and clinical isolates, and comparing the results with those from the traditional Quellung reaction or antiserum panel gel precipitation, in addition to real-time PCR analysis. The taxonomic identifications of 422 publicly available (GenBank) genome sequences of S. pneumoniae, Streptococcus pseudopneumoniae and Streptococcus mitis were assessed by whole-genome sequence average nucleotide identity based on blast (ANIb) analysis. RESULTS The proposed sequetyping protocol generates a 1017 bp whole cpsB region sequence, increasing resolution for serotype identification in pneumococcus isolates. The identifications of all GenBank genome sequences of S. pneumoniae were confirmed, whereas most of the S. pseudopneumoniae and almost all of the S. mitis genome sequences did not fulfil the ANIb thresholds for species-level identification. The housekeeping biomarker gene, groEL, correctly identified S. pneumoniae but often misclassified S. pseudopneumoniae and S. mitis as S. pneumoniae. CONCLUSIONS These studies affirm the importance of applying reliable identification protocols for S. pneumoniae before serotyping; our protocols provide reliable diagnostic tools, as well as an improved workflow, for serotype identification of pneumococcus and differentiation of serogroup 6 types.
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Affiliation(s)
- Lucia Gonzales-Siles
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Francisco Salvà-Serra
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden.,Culture Collection University of Gothenburg (CCUG), Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden.,Microbiology, Department of Biology, University of the Balearic Islands, Palma de Mallorca, Spain
| | - Anna Degerman
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden
| | - Rickard Nordén
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden
| | - Magnus Lindh
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden
| | - Susann Skovbjerg
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden.,Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Edward R B Moore
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden.,Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy of the University of Gothenburg, Gothenburg, Sweden.,Culture Collection University of Gothenburg (CCUG), Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden
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13
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Yahiaoui RY, Bootsma HJ, den Heijer CDJ, Pluister GN, John Paget W, Spreeuwenberg P, Trzcinski K, Stobberingh EE. Distribution of serotypes and patterns of antimicrobial resistance among commensal Streptococcus pneumoniae in nine European countries. BMC Infect Dis 2018; 18:440. [PMID: 30157780 PMCID: PMC6116386 DOI: 10.1186/s12879-018-3341-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 08/17/2018] [Indexed: 11/26/2022] Open
Abstract
Background Streptococcus pneumoniae is a commensal of the human upper respiratory tract and a major cause of morbidity and mortality worldwide. This paper presents the distribution of serotypes and antimicrobial resistance in commensal S. pneumoniae strains cultured from healthy carriers older than four years of age in nine European countries. Methods Nasal swabs from healthy persons (age between 4 and 107 years old) were obtained by general practitioners from each country from November 2010 to August 2011. Swabs were cultured for S. pneumoniae using a standardized protocol. Antibiotic resistance was determined for isolated S. pneumoniae by broth microdilution. Capsular sequencing typing was used to identify serotypes, followed by serotype-specific PCR assays in case of ambiguous results. Results Thirty-two thousand one hundred sixty-one nasal swabs were collected from which 937 S. pneumoniae were isolated. A large variation in serotype distribution and antimicrobial resistant serotypes across the participating countries was observed. Pneumococcal vaccination was associated with a higher risk of pneumococcal colonization and antimicrobial resistance independently of country and vaccine used, either conjugate vaccine or PPV 23). Conclusions Serotype 11A was the most common in carriage followed by serotypes 23A and 19A. The serotypes showing the highest resistance to penicillin were 14 followed by 19A. Serotype 15A showed the highest proportion of multidrug resistance. Electronic supplementary material The online version of this article (10.1186/s12879-018-3341-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rachid Y Yahiaoui
- Maastricht University Medical Centre/CAPHRI, Maastricht, The Netherlands. .,Haga hospital, Department medical microbiology, The Hague, The Netherlands.
| | - Hester J Bootsma
- Centre for Infectious Diseases Research Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | | | - Gerlinde N Pluister
- Centre for Infectious Diseases Research Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - W John Paget
- NIVEL, The Netherlands Institute for Health Services Research, Utrecht, The Netherlands.,Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Peter Spreeuwenberg
- NIVEL, The Netherlands Institute for Health Services Research, Utrecht, The Netherlands
| | - Krzysztof Trzcinski
- Centre for Infectious Diseases Research Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.,Paediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Ellen E Stobberingh
- Maastricht University Medical Centre/CAPHRI, Maastricht, The Netherlands.,Centre for Infectious Diseases Research Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
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14
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Antibiotic Susceptibility and Prevalence of Adhesion Genes in Streptococcus pneumoniae Isolates Detected in Carrier Children in Tehran. Jundishapur J Microbiol 2018. [DOI: 10.5812/jjm.13256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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15
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Prato R, Fortunato F, Cappelli MG, Chironna M, Martinelli D. Effectiveness of the 13-valent pneumococcal conjugate vaccine against adult pneumonia in Italy: a case-control study in a 2-year prospective cohort. BMJ Open 2018; 8:e019034. [PMID: 29581200 PMCID: PMC5875676 DOI: 10.1136/bmjopen-2017-019034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES Current strategies to prevent adult pneumococcal disease have been recently reviewed in Italy. We did a postlicensure study to estimate the direct vaccine effectiveness (VE) of the 13-valent pneumococcal conjugate vaccine (PCV13) against adult pneumococcal community-acquired pneumonia (pCAP). STUDY DESIGN Between 2013 and 2015, a 2-year prospective cohort study of adults with CAP was conducted in the Apulia region of Italy where the average vaccine uptake of PCV13 was 32% among adults ≥65 years. The test-negative design was used to estimate VE against all episodes of confirmed pCAP and vaccine-type (VT)-CAP. VE in a subgroup of patients managed in the community was also estimated using a matched case-control design. VE was calculated as one minus the OR times 100%. RESULTS The overall VE of PCV13 was 33.2% (95% CI -106.6% to 82%) against pCAP irrespective of serotype and 38.1% (95% CI -131.9% to 89%) against VT-CAP in the cohort of adults ≥65 years. The VE was 42.3% (95% CI -244.1% to 94.7%) against VT-CAP in the age group at higher vaccine uptake. For the subgroup of cases managed in the community, the overall VE against disease due to any pneumococcal strain was 88.1% (95% CI 4.2% to 98.5%) and 91.7% (95% CI 13.1% to 99.2%) when we controlled for underlying conditions. CONCLUSIONS Although our results are non-significant, PCV13 promises to be effective against all confirmed pCAP already with modest levels of uptake in the population of adults ≥65 years of age. Larger studies are needed to confirm the direct vaccine benefits.
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Affiliation(s)
- Rosa Prato
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Puglia, Italy
| | - Francesca Fortunato
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Puglia, Italy
| | | | - Maria Chironna
- Department of Biomedical Science and Human Oncology, University of Bari Aldo Moro, Bari, Puglia, Italy
| | - Domenico Martinelli
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Puglia, Italy
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16
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Rahman NA, Sharudin A, Diah S, Muharram SH. Serotyping of Brunei pneumococcal clinical strains and the investigation of their capability to adhere and invade a brain endothelium model. Microb Pathog 2017; 110:352-358. [PMID: 28711510 DOI: 10.1016/j.micpath.2017.07.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Pneumococcal infections have caused morbidity and mortality globally. Streptococcus pneumoniae (pneumococci) are commensal bacteria that colonize the nasopharynx, asymptomatically. From there, pneumococci can spread in the lungs causing pneumonia and disseminate in the bloodstream causing bacteremia (sepsis) and reach the brain leading to meningitis. Endothelial cells are one of the most important components of the blood-brain barrier that separates the blood from the brain and plays the first protective role against pneumococcal entry. Thus this study aimed to investigate on the ability of non-meningitis pneumococcal clinical strains to adhere and invade a brain endothelium model. METHODS Two pneumococcal Brunei clinical strains were serotyped by multiplex PCR method using oligonucleotide sequences derived from Centers for Disease Control and Prevention. A validated immortalised mouse brain endothelial cell line (bEnd.3) was used as a brain endothelium model for the study of the pneumococcal breach of the blood-brain barrier using an adherence and invasion assay. RESULTS Both of the pneumococcal clinical strains were found to be serotype 19F, a common circulating serotype in Southeast Asia and globally and possess the ability to adhere and invade the brain endothelial cells. CONCLUSION In addition, this is the first report on the serotype identification of pneumococci in Brunei Darussalam and their application on a brain endothelium model. Further studies are required to understand the virulence capabilities of the clinical strains.
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Affiliation(s)
- Nurul Adhwa Rahman
- Pengiran Anak Puteri Rashidah Sa'adatul Bolkiah Institute of Health Sciences, Universiti Brunei Darussalam, Brunei Darussalam.
| | - Aishah Sharudin
- School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Suwarni Diah
- Pengiran Anak Puteri Rashidah Sa'adatul Bolkiah Institute of Health Sciences, Universiti Brunei Darussalam, Brunei Darussalam
| | - Siti Hanna Muharram
- Pengiran Anak Puteri Rashidah Sa'adatul Bolkiah Institute of Health Sciences, Universiti Brunei Darussalam, Brunei Darussalam
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17
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van Tonder AJ, Bray JE, Quirk SJ, Haraldsson G, Jolley KA, Maiden MCJ, Hoffmann S, Bentley SD, Haraldsson Á, Erlendsdóttir H, Kristinsson KG, Brueggemann AB. Putatively novel serotypes and the potential for reduced vaccine effectiveness: capsular locus diversity revealed among 5405 pneumococcal genomes. Microb Genom 2016; 2:000090. [PMID: 28133541 PMCID: PMC5266551 DOI: 10.1099/mgen.0.000090] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/20/2016] [Indexed: 01/14/2023] Open
Abstract
The pneumococcus is a leading global pathogen and a key virulence factor possessed by the majority of pneumococci is an antigenic polysaccharide capsule ('serotype'), which is encoded by the capsular (cps) locus. Approximately 100 different serotypes are known, but the extent of sequence diversity within the cps loci of individual serotypes is not well understood. Investigating serotype-specific sequence variation is crucial to the design of sequence-based serotyping methodology, understanding pneumococcal conjugate vaccine (PCV) effectiveness and the design of future PCVs. The availability of large genome datasets makes it possible to assess population-level variation among pneumococcal serotypes and in this study 5405 pneumococcal genomes were used to investigate cps locus diversity among 49 different serotypes. Pneumococci had been recovered between 1916 and 2014 from people of all ages living in 51 countries. Serotypes were deduced bioinformatically, cps locus sequences were extracted and variation was assessed within the cps locus, in the context of pneumococcal genetic lineages. Overall, cps locus sequence diversity varied markedly: low to moderate diversity was revealed among serogroups/types 1, 3, 7, 9, 11 and 22; whereas serogroups/types 6, 19, 23, 14, 15, 18, 33 and 35 displayed high diversity. Putative novel and/or hybrid cps loci were identified among all serogroups/types apart from 1, 3 and 9. This study demonstrated that cps locus sequence diversity varied widely between serogroups/types. Investigation of the biochemical structure of the polysaccharide capsule of major variants, particularly PCV-related serotypes and those that appear to be novel or hybrids, is warranted.
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Affiliation(s)
| | - James E. Bray
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Sigríður J. Quirk
- Clinical Microbiology, University of Iceland and Landspitali University Hospital, Reykjavik, Iceland
| | - Gunnsteinn Haraldsson
- Clinical Microbiology, University of Iceland and Landspitali University Hospital, Reykjavik, Iceland
| | - Keith A. Jolley
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | - Steen Hoffmann
- Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
| | - Stephen D. Bentley
- Pathogen Genomics, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Ásgeir Haraldsson
- Clinical Microbiology, University of Iceland and Landspitali University Hospital, Reykjavik, Iceland
| | - Helga Erlendsdóttir
- Clinical Microbiology, University of Iceland and Landspitali University Hospital, Reykjavik, Iceland
| | - Karl G. Kristinsson
- Clinical Microbiology, University of Iceland and Landspitali University Hospital, Reykjavik, Iceland
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18
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Gharailoo Z, Mousavi SF, Halvani N, Feizabadi MM. Antimicrobial Resistant Pattern and Capsular Typing of Streptococcus Pneumoniae Isolated from Children in Sistan -Baluchestan. MAEDICA 2016; 11:203-207. [PMID: 28694854 PMCID: PMC5486161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
BACKGROUND Ankyloglossia is an anatomic developmental anomaly determining by thick and short, fi brotic ferenum. Tongue changes have severe eff ects on occlusion and oropharyngeal structures. The aim of this study was to evaluate the position of hyoid in children 7-11 years` old with ankyloglossia in lateral cephalometric radiographs. MATERIALS AND METHOD In this study 260 nasopharyngeal swabs were taken from non-vaccinated healthy children between 6 months to 6 years old at medical centers in Sistan-Baluchestan during August 2013 to January 2014. These samples were cultured on blood agar. Primary identifi cation of bacterial isolated was determined by biochemical analysis and molecular tests. Capsular typing was performed by Multiplex PCR using primers targeting cps locus that is highly conserved among diff erent capsular types. The master mixes for PCR were grouped them into six multiplex reactions. RESULTS Out of 260 nasopharyngeal swabs, 42 isolates of Streptococcus pneumoniae were detected and identifi ed. The overall pneumococcal carriage rate was 16.1%. The most frequently isolated capsular types were: 6A/B, 19A, 19F and 23F. These capsular types accounted for 49.9% of all strains detected. CONCLUSION We found that the prevalence of pneumococcal carriage among non-vaccinated children under six years old is about 16%. Our study provides much data about carriage rate and pneumococcal capsular types in preschool children, which is necessary for predicting the diff erent valent pneumococcal conjugated vaccines in Iran.
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Affiliation(s)
- Zahra Gharailoo
- Department of Microbiology, School of Medicine, Tehran University of Medical Science, Tehran, Iran
| | - Seyed Fazlollah Mousavi
- Department of Bacteriology and Microbiology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Niloofar Halvani
- Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Mehdi Feizabadi
- Department of Microbiology, School of Medicine, Tehran University of Medical Science, Tehran, Iran
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Application of capsular sequence typing (CST) to serotype non-viable Streptococcus pneumoniae isolates from an old collection. Eur J Clin Microbiol Infect Dis 2016; 35:2025-2031. [PMID: 27580910 DOI: 10.1007/s10096-016-2755-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 08/09/2016] [Indexed: 10/21/2022]
Abstract
Serotyping of Streptococcus pneumoniae is essential for monitoring changes in the pneumococcal population and the impact of vaccines. Recently, various DNA-based methods have become available and are increasingly used because they are cheaper and easier to perform than the Quellung reaction. Our aim was to apply a DNA-based method, capsular sequence typing (CST), to a collection of non-viable lyophilized pneumococcal isolates dating from the 1980s to elucidate the serotypes circulating in Italy 30 years ago. As a preliminary evaluation of the method, CST was applied to 68 recent pneumococcal isolates representative of the most common serotypes circulating in Italy in invasive pneumococcal disease (IPD) previously serotyped by the Quellung reaction. CST was then applied to 132 lyophilized non-viable isolates. A serotype-specific polymerase chain reaction (PCR), using primers suggested by the Centers for Disease Control and Prevention (CDC), was performed when CST did not yield a univocal serotype. Considering the control isolates, CST concordance with the Quellung reaction was 95.6 %. For the non-viable lyophilized isolates, CST identified a univocal serotype for 59.4 % of the isolates. This percentage increased to 78.1 % if CST was combined with serotype-specific PCR. The most frequent serotypes in the collection of non-viable strains were: 3 (15.6 %), 14 (11.7 %), 35B (5.5 %), 19A (5.5 %), and 8 (4.7 %). CST proved to be a valid method for serotyping pneumococcal strains and provided information about pneumococcal serotypes present in Italy 30 years ago. The combination of CST with serotype-specific PCR was an effective strategy to identify pneumococcal serotypes that can be suggested also for routine laboratories.
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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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Exopolysaccharide production and ropy phenotype are determined by two gene clusters in putative probiotic strain Lactobacillus paraplantarum BGCG11. Appl Environ Microbiol 2016; 81:1387-96. [PMID: 25527533 DOI: 10.1128/aem.03028-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Lactobacillus paraplantarum BGCG11, a putative probiotic strain isolated from a soft, white, artisanal cheese, produces a high molecular-weight heteropolysaccharide, exopolysaccharide (EPS)-CG11, responsible for the ropy phenotype and immunomodulatory activity of the strain. In this study, a 26.4-kb region originating from the pCG1 plasmid, previously shown to be responsible for the production of EPS-CG11 and a ropy phenotype, was cloned, sequenced, and functionally characterized. In this region 16 putative open reading frames (ORFs), encoding enzymes for the production of EPS-CG11, were organized in specific loci involved in the biosynthesis of the repeat unit, polymerization, export, regulation, and chain length determination. Interestingly, downstream of the eps gene cluster, a putative transposase gene was identified, followed by an additional rfb gene cluster containing the rfbACBD genes, the ones most probably responsible for dTDP-L-rhamnose biosynthesis. The functional analysis showed that the production of the high-molecular-weight fraction of EPS-CG11 was absent in two knockout mutants, one in the eps and the other in the rfb gene cluster, as confirmed by size exclusion chromatography analysis. Therefore, both eps and rfb genes clusters are prerequisites for the production of high-molecular-weight EPS-CG11 and for the ropy phenotype of strain L. paraplantarum BGCG11.
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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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Capsule Switching and Antimicrobial Resistance Acquired during Repeated Streptococcus pneumoniae Pneumonia Episodes. J Clin Microbiol 2015; 53:3318-24. [PMID: 26269621 DOI: 10.1128/jcm.01222-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 08/03/2015] [Indexed: 01/18/2023] Open
Abstract
Streptococcus pneumoniae colonizes the nasopharyngeal mucus in healthy people and causes otitis media, pneumonia, bacteremia, and meningitis. In this study, we analyzed an S. pneumoniae strain that caused 7 repeated pneumonia episodes in an 80-month-old patient with cerebral palsy during a period of 25 months. A total of 10 S. pneumoniae strains were obtained from sputum samples, and serotype 6B was isolated from samples from the first 5 episodes, whereas serotype 6A was isolated from samples from the last 2. Whole-genome sequencing showed clonality of the 10 isolates with 10 single nucleotide polymorphisms (SNPs) in the genomes. Among these SNPs, one single point mutation in the wciP gene was presumed to relate to the serotype switching from 6B to 6A, and the other mutations in parC and gyrA were related to fluoroquinolone resistance. These results suggested that an S. pneumoniae strain, which asymptomatically colonized the patient's nasopharynx or was horizontally transmitted from an asymptomatic carrier, caused the repeated pneumonia events. Phenotypic variations in the capsule type and antimicrobial susceptibility occurred during the carrier state. Hyporesponsiveness to serotypes 6B and 6A of S. pneumoniae was found even after vaccination with the 7-valent pneumococcal conjugate vaccine and the 23-valent pneumococcal polysaccharide vaccine. After an additional vaccination with the 13-valent pneumococcal conjugate vaccine, opsonic activities for both serotypes 6A and 6B significantly increased and are expected to prevent relapse by the same strain.
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Genomics Reveals the Worldwide Distribution of Multidrug-Resistant Serotype 6E Pneumococci. J Clin Microbiol 2015; 53:2271-85. [PMID: 25972423 PMCID: PMC4473186 DOI: 10.1128/jcm.00744-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 05/06/2015] [Indexed: 02/02/2023] Open
Abstract
The pneumococcus is a leading pathogen infecting children and adults. Safe, effective vaccines exist, and they work by inducing antibodies to the polysaccharide capsule (unique for each serotype) that surrounds the cell; however, current vaccines are limited by the fact that only a few of the nearly 100 antigenically distinct serotypes are included in the formulations. Within the serotypes, serogroup 6 pneumococci are a frequent cause of serious disease and common colonizers of the nasopharynx in children. Serotype 6E was first reported in 2004 but was thought to be rare; however, we and others have detected serotype 6E among recent pneumococcal collections. Therefore, we analyzed a diverse data set of ∼1,000 serogroup 6 genomes, assessed the prevalence and distribution of serotype 6E, analyzed the genetic diversity among serogroup 6 pneumococci, and investigated whether pneumococcal conjugate vaccine-induced serotype 6A and 6B antibodies mediate the killing of serotype 6E pneumococci. We found that 43% of all genomes were of serotype 6E, and they were recovered worldwide from healthy children and patients of all ages with pneumococcal disease. Four genetic lineages, three of which were multidrug resistant, described ∼90% of the serotype 6E pneumococci. Serological assays demonstrated that vaccine-induced serotype 6B antibodies were able to elicit killing of serotype 6E pneumococci. We also revealed three major genetic clusters of serotype 6A capsular sequences, discovered a new hybrid 6C/6E serotype, and identified 44 examples of serotype switching. Therefore, while vaccines appear to offer protection against serotype 6E, genetic variants may reduce vaccine efficacy in the longer term because of the emergence of serotypes that can evade vaccine-induced immunity.
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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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Changes in the incidence of Streptococcus pneumoniae bacteremia and its serotypes over 10 years in one hospital in South Korea. Vaccine 2014; 32:6403-7. [DOI: 10.1016/j.vaccine.2014.09.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/11/2014] [Accepted: 09/26/2014] [Indexed: 11/17/2022]
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Kawaguchiya M, Urushibara N, Kobayashi N. High prevalence of genotype 6E (putative serotype 6E) among noninvasive/colonization isolates of Streptococcus pneumoniae in northern Japan. Microb Drug Resist 2014; 21:209-14. [PMID: 25361198 DOI: 10.1089/mdr.2014.0181] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Serogroup 6 of Streptococcus pneumoniae contains four established serotypes (6A-6D). Recently, putative serotype 6E (genotype 6E) was proposed as a novel type, which is cross-reactive with 6B-specific antiserum, but its capsular polysaccharide synthesis (cps) locus is genetically distinct from those of serotypes 6A and 6B. In the present study, prevalence of genotype 6E was analyzed by a newly designed multiplex polymerase chain reaction (PCR) for noninvasive or colonizing S. pneumoniae isolates in northern Japan assigned to serogroup 6 in our previous study by the sequential multiplex PCR developed by Pai et al. Among the isolates previously assigned to 6A and 6B, 2.2% (1/45) and 77.3% (140/181) of isolates, respectively, were revealed to have cps genes of genotype 6E. Eight 6E isolates selected for further analysis were found to have identical or highly similar sequences of cps genes (wzg, wzh, wze, wciN, wciP, and wzy) to those of strains previously reported as putative serotype 6E, and all the isolates were classified into sequence type 90 (ST90). Reanalysis of genetic traits on penicillin and macrolide resistance clarified significantly higher rates of three pbp mutations (gPRSP) and ermB in genotype 6E than in serotypes 6A and 6B. These findings suggested a need for detection of genotype 6E in the surveillance of S. pneumoniae serotypes.
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Affiliation(s)
- Mitsuyo Kawaguchiya
- Department of Hygiene, School of Medicine, Sapporo Medical University , Sapporo, Japan
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28
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Capsular polysaccharide gene diversity of pneumococcal serotypes 6A, 6B, 6C, and 6D. Int J Med Microbiol 2014; 304:1109-17. [PMID: 25220816 DOI: 10.1016/j.ijmm.2014.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 08/04/2014] [Accepted: 08/10/2014] [Indexed: 11/23/2022] Open
Abstract
This study was performed to better understand the genetic diversity and evolutionary relatedness of pneumococcal serotypes 6A, 6B, 6C, and 6D. Multi-locus sequence typing (MLST) was performed for 160 serogroup 6 isolates from clinical specimens collected from children between 1991 and 2010. We identified 38 sequence types (STs) comprising five clonal complexes with 12 singletons. Although most STs were confined to a single serotype, some STs were shared by two serotypes, and one ST was shared by three serotypes. Many STs of serotype 6A showed genetic relatedness with those of serotype 6C or 6D in eBURST analysis. Five capsular polysaccharide (cps) genes - wchA, wciO, wciP, wzy, and wzx - were analysed in 74 isolates from our clinical samples and in 36 isolates from GenBank. There were several profiles and clades in each serotype on the analysis of the concatenated sequences of the five cps genes. Small genetic distances between serotypes 6A and 6B and between serotypes 6C and 6D were observed while serotype 6B with an indel sequence formed a distinct clade. When comparing the individual cps genes between the serotypes, there was also a high level of similarity in the wchA and wciO gene sequences between serotype 6C and serotype 6D. On the other hand, serotypes 6A and 6D had the most highly similar wzy and wzx gene sequences. The wzy sequences of serotype 6C were nearly identical (99.6%) to those of serotype 6A clade II strains. In conclusion, we revealed the diversity of the genetic background and cps sequences in each pneumococcal serotype of serogroup 6. Pneumococcal serotype diversity might be attributable to complex serial mutation and recombination events.
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Croucher NJ, Hanage WP, Harris SR, McGee L, van der Linden M, de Lencastre H, Sá-Leão R, Song JH, Ko KS, Beall B, Klugman KP, Parkhill J, Tomasz A, Kristinsson KG, Bentley SD. Variable recombination dynamics during the emergence, transmission and 'disarming' of a multidrug-resistant pneumococcal clone. BMC Biol 2014; 12:49. [PMID: 24957517 PMCID: PMC4094930 DOI: 10.1186/1741-7007-12-49] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 06/12/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pneumococcal β-lactam resistance was first detected in Iceland in the late 1980s, and subsequently peaked at almost 25% of clinical isolates in the mid-1990s largely due to the spread of the internationally-disseminated multidrug-resistant PMEN2 (or Spain6B-2) clone of Streptococcus pneumoniae. RESULTS Whole genome sequencing of an international collection of 189 isolates estimated that PMEN2 emerged around the late 1960s, developing resistance through multiple homologous recombinations and the acquisition of a Tn5253-type integrative and conjugative element (ICE). Two distinct clades entered Iceland in the 1980s, one of which had acquired a macrolide resistance cassette and was estimated to have risen sharply in its prevalence by coalescent analysis. Transmission within the island appeared to mainly emanate from Reykjavík and the Southern Peninsular, with evolution of the bacteria effectively clonal, mainly due to a prophage disrupting a gene necessary for genetic transformation in many isolates. A subsequent decline in PMEN2's prevalence in Iceland coincided with a nationwide campaign that reduced dispensing of antibiotics to children in an attempt to limit its spread. Specific mutations causing inactivation or loss of ICE-borne resistance genes were identified from the genome sequences of isolates that reverted to drug susceptible phenotypes around this time. Phylogenetic analysis revealed some of these occurred on multiple occasions in parallel, suggesting they may have been at least temporarily advantageous. However, alteration of 'core' sequences associated with resistance was precluded by the absence of any substantial homologous recombination events. CONCLUSIONS PMEN2's clonal evolution was successful over the short-term in a limited geographical region, but its inability to alter major antigens or 'core' gene sequences associated with resistance may have prevented persistence over longer timespans.
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Affiliation(s)
- Nicholas J Croucher
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston MA 02115, USA
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Department of Infectious Disease Epidemiology, Imperial College, Norfolk Place, London W2 1NY, UK
| | - William P Hanage
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston MA 02115, USA
| | - Simon R Harris
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Lesley McGee
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Mark van der Linden
- Institute for Medical Microbiology, National Reference Center for Streptococci, University Hospital, RWTH Aachen, Pauwelsstrasse 30, Aachen, Germany
| | - Herminia de Lencastre
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- Laboratory of Microbiology, The Rockefeller University, New York, New York, USA
| | - Raquel Sá-Leão
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Jae-Hoon Song
- Samsung Medical Centre, Sungkyunkwan University School of Medicine and Asia Pacific Foundation for Infectious Disease, Seoul, South Korea
| | - Kwan Soo Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Bernard Beall
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Keith P Klugman
- Hubert Department of Global Health, Rollins School of Public Health and Division of Infectious Diseases, School of Medicine, Emory University, Atlanta, Georgia, USA
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases, Gauteng, South Africa
| | - Julian Parkhill
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Alexander Tomasz
- Laboratory of Microbiology, The Rockefeller University, New York, New York, USA
| | - Karl G Kristinsson
- Clinical Microbiology Department, Landspitali University Hospital and University of Iceland, Reykjavík, Iceland
| | - Stephen D Bentley
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge CB2 0SP, UK
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Kawaguchiya M, Urushibara N, Ghosh S, Kuwahara O, Morimoto S, Ito M, Kudo K, Kobayashi N. Serotype distribution and susceptibility to penicillin and erythromycin among noninvasive or colonization isolates of Streptococcus pneumoniae in northern Japan: a cross-sectional study in the pre-PCV7 routine immunization period. Microb Drug Resist 2014; 20:456-65. [PMID: 24766085 DOI: 10.1089/mdr.2013.0196] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Distribution of serotypes, prevalence of resistance to penicillin and/or erythromycin (EM), and its genetic traits were analyzed for a total of 1,061 noninvasive or colonization isolates of Streptococcus pneumoniae (998 and 61 isolates from children and adults, respectively) in Hokkaido, northern main island of Japan, in the year 2011, the pre-PCV7 routine immunization period. Serotype deduction was performed by sequential multiplex polymerase chain reaction (PCR), employing mutagenic PCR-restriction fragment length polymorphism for discrimination of 6A/C and 6B/D. Unaltered three PBP genes and macrolide resistance genes erm(B) and mef(A/E) were detected by multiplex PCR. Among isolates from children, 25 serotypes, including the prevalent types 6B (17.5%), 19F (15.6%), 23F (12.2%), and 6C (11.6%), were identified, revealing the PCV7 and PCV13 coverage rates as 48.2% and 60.3%, respectively, while serotype 3 was the most frequent (19.0%) among isolates from adults. Most of the pediatric isolates (96.8%) exhibited resistance to EM (minimum inhibitory concentration [MIC], ≥1 μg/ml), with a higher prevalence of erm(B) (67.2%) than mef(A/E) (39.7%). erm(B) was associated with high-level EM resistance (MIC, ≥128 μg/ml) and distributed at high detection rates to major serotypes 23F (85.2%) and 6B (85.1%), as well as minor serotypes 3, 10A, 14, 15B, 15C, 19A, and 23A (>90%). While penicillin-resistant S. pneumoniae (PRSP) (penicillin G-MIC, 2-3 μg/ml) was detected in 7.8% of isolates from children, the most common PBP gene genotype was gPRSP (three altered genes pbp1a, 2x, and 2b; 38.3%), which was detected at higher rates (>60%) in the dominant serotypes 23F, 6B, and 19F, and minor serotypes 6D and 15A. Dominant serotypes in the S. pneumoniae isolates were generally similar to those reported for invasive strains, despite lower coverage rates by PCV7/13. The importance of further surveillance on incidence and drug resistance in the post-PCV7 period was suggested for non-PCV7/13 serotypes 6C, 6D, 10A, 15A, 15B, 15C, 23A, and 35B.
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Affiliation(s)
- Mitsuyo Kawaguchiya
- 1 Department of Hygiene, Sapporo Medical University School of Medicine , Sapporo, Japan
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Prevalence of isolates of Streptococcus pneumoniae putative serotype 6E in South Korea. J Clin Microbiol 2014; 52:2096-9. [PMID: 24719436 DOI: 10.1128/jcm.00228-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The prevalence of serogroup 6 among 1,206 Streptococcus pneumoniae clinical isolates collected from Korean hospitals over three periods (1996 to 2001, 2004 to 2006, and 2008 to 2009) was investigated. The number of serogroup 6 isolates increased from 9.7 to 17.5% over the three periods. While the proportion of serotype 6A and 6D isolates increased significantly, that of serotype 6B isolates decreased. Twenty-four isolates (2.0%) were typed as the recently identified putative serotype 6E or genetic variants of serotype 6B. The results suggest that the lack of change in frequency of serotype 6B, in spite of the introduction of the PCV7 vaccine as seen in previous studies in South Korea, might be due mainly to the improper inclusion of putative serotype 6E in serotype 6B. All but three serotype 6E isolates belonged to CC90, indicating their clonal expansion.
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32
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Streptococcus pneumoniae serogroup 6 clones over two decades. Epidemiol Infect 2014; 142:2501-13. [PMID: 24641988 DOI: 10.1017/s0950268814000508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The major evolutionary stresses on Streptococcus pneumoniae are thought to be the widespread use of antibiotics and the deployment of effective vaccines against the capsular polysaccharides. Our current knowledge of genetic lineages among pneumococcal isolates comes largely from investigations just before and after the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) introduced in 2000. We examined 66 serogroup 6 isolates from the 1970s, long before the introduction of PCV7 and before widespread penicillin resistance was common in Birmingham, Alabama, to look for ancestors of the clones that came into play around the introduction of the PCV7 vaccine. The hypothesis was that some clonal complexes, if not individual clones, would be stable enough to persist over this period of time. We compared the 1970s isolates with 122 isolates from the 1990s in US and worldwide collections. Genotyping with pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) revealed that while some clones were probably localized to our area, others have persisted within groups that have expanded or diminished over the years.
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Janoir C, Cohen R, Levy C, Bingen E, Lepoutre A, Gutmann L, Varon E. Clonal expansion of the macrolide resistant ST386 within pneumococcal serotype 6C in France. PLoS One 2014; 9:e90935. [PMID: 24603763 PMCID: PMC3946248 DOI: 10.1371/journal.pone.0090935] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 02/04/2014] [Indexed: 11/19/2022] Open
Abstract
In France, the use of the 7-valent pneumococcal conjugate vaccine (PCV7) lead to an overall significant decrease in PCV7 invasive pneumococcal disease (IPD) incidence. However, the decrease in vaccine serotype prevalence was partially counterbalanced by the serotype replacement phenomenon. In this study, we analyzed the role of the newly described serotype 6C as one of the replacement serotypes. This work was conducted on a large time scale from the early PCV7 era (2002-2003) to the PCV13 era (2010-2011), both on IPD strains recovered from the whole population and nasopharyngeal colonizing strains isolated in infant less than two years, who are known to be the main reservoir for pneumococci. Serotype 6C took advantage over 6A and 6B serotypes, which both decreased over time. A continuous and significant increase in 6C IPD was observed in adults along the study period; in contrast, in children less than two years, only an increase in 6C nasopharyngeal carriage was found, the prevalence of serotype 6C in IPD remaining very low over time. Among 101 6C invasive and colonizing strains studied by MLST, 24 STs were found to be related to three major clonal complexes, CC395, CC176, and CC315. STs related to CC176 tend to disappear after 2009 and were essentially replaced by ST386 (CC315), which dramatically increased over time. This clonal expansion may be explained by the erythromycin and tetracycline resistances associated with this clone. Finally, the decrease observed in nasopharyngeal 6C carriage since 2010, likely related to the PCV13 introduction in the French immunization schedule, is expected to lead to a decrease in 6C IPD in adults thereafter.
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Affiliation(s)
- Claire Janoir
- Centre National de Référence des Pneumocoques (CNRP), AP-HP Hôpital Européen Georges-Pompidou, Paris, France
- Département de Microbiologie, Faculté de Pharmacie EA4043, Châtenay-Malabry, France
| | - Robert Cohen
- Département de Microbiologie, Centre Hospitalier Intercommunal de Créteil, Créteil, France
- Centre de Recherche Clinique, Centre Hospitalier Intercommunal de Créteil, Créteil, France
- Association Clinique Thérapeutique Infantile du Val de Marne (ACTIV), Saint-Maur-des-Fossés, France
- Groupe de Pathologie Infectieuse Pédiatrique (GPIP), Paris, France
| | - Corinne Levy
- Centre de Recherche Clinique, Centre Hospitalier Intercommunal de Créteil, Créteil, France
- Association Clinique Thérapeutique Infantile du Val de Marne (ACTIV), Saint-Maur-des-Fossés, France
- Groupe de Pathologie Infectieuse Pédiatrique (GPIP), Paris, France
| | - Edouard Bingen
- Groupe de Pathologie Infectieuse Pédiatrique (GPIP), Paris, France
- Département de Microbiologie, Université Denis-Diderot-Paris 7, AP-HP Hôpital Robert-Debré, Paris, France
| | - Agnès Lepoutre
- Département de Maladies Infectieuses, Institut de Veille Sanitaire, Saint-Maurice, France
| | - Laurent Gutmann
- Centre National de Référence des Pneumocoques (CNRP), AP-HP Hôpital Européen Georges-Pompidou, Paris, France
- Laboratoire de Microbiologie, AP-HP Hôpital Européen Georges-Pompidou, Paris, France
- INSERM, U872, Paris, France
| | - Emmanuelle Varon
- Centre National de Référence des Pneumocoques (CNRP), AP-HP Hôpital Européen Georges-Pompidou, Paris, France
- Laboratoire de Microbiologie, AP-HP Hôpital Européen Georges-Pompidou, Paris, France
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Otsuka T, Chang B, Wada A, Okazaki M. Molecular epidemiology and serogroup 6 capsular gene evolution of pneumococcal carriage in a Japanese birth cohort study. J Med Microbiol 2013; 62:1868-1875. [DOI: 10.1099/jmm.0.066316-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Antibiotic resistance in Streptococcus pneumoniae is a major concern worldwide. However, it is unclear whether resistance is associated with only a few highly prevalent clones or numerous and diverse clones. We monitored 349 healthy children and obtained nasopharyngeal cultures at five time points coinciding with health check-ups (4, 7, 10, 18 and 36 months) between 2008 and 2012. A total of 497 S. pneumoniae isolates from 257 healthy children were characterized using capsular serotyping, multilocus sequence typing and antibiotic resistance genotyping (ermB, mefA/E and pbp mutations). Among these isolates, 25 serotypes and 66 sequence types (STs) were found, including 24 new STs with 11 new alleles. Although resistance was present in a variety of ST clones, most of the clones (57/66, 86.4 %) had one specific resistant or susceptible genotype. Of 233 phenotypically penicillin-non-susceptible isolates, 196 (84.1 %) belonged to only six clones, comprising ST906B, ST23619F, ST24223F, ST37876A, ST143723F and ST33823A and their variants. We concluded that drug-resistant S. pneumoniae is associated with a limited number of highly prevalent clones that are capable of adapting to the community setting. Furthermore, we analysed the capsular gene evolution in serogroup 6. The strain ST29246D was probably the result of recombination of a 3563 bp fragment of the capsule locus acquired by an ST29246C strain from an ST906B or ST29246B strain. Compared with previous studies, our results showed a different recombination site (wciN and wzx) and a different cps profile (8-7-11), indicating that serogroup 6 strains have multiple sites for cps recombination as a mechanism of vaccine escape.
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Affiliation(s)
- Taketo Otsuka
- Department of Pediatrics, Sado General Hospital 161 Chigusa, Sado, Niigata, 952-1209, Japan
| | - Bin Chang
- Department of Bacteriology I, National Institute of Infectious Diseases 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Akihito Wada
- Department of Bacteriology I, National Institute of Infectious Diseases 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan
| | - Minoru Okazaki
- Department of Pediatrics, Sado General Hospital 161 Chigusa, Sado, Niigata, 952-1209, Japan
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Martinelli D, Pedalino B, Cappelli MG, Caputi G, Sallustio A, Fortunato F, Tafuri S, Cozza V, Germinario C, Chironna M, Prato R. Towards the 13-valent pneumococcal conjugate universal vaccination: effectiveness in the transition era between PCV7 and PCV13 in Italy, 2010-2013. Hum Vaccin Immunother 2013; 10:33-9. [PMID: 24096297 DOI: 10.4161/hv.26650] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Pneumococcal disease epidemiology has changed after introduction of pneumococcal conjugate vaccines. Seven-valent vaccine (PCV7) has been effective in reducing invasive pneumococcal disease (IPD). In Europe, PCV13 effectiveness was estimated at 78% (95% CI: -18-96%) for 2-priming doses. In Italy, PCV7 was introduced in 2006 in the childhood immunization schedule and replaced with PCV13 in 2010. In Apulia, vaccination coverage has reached 95.1% (birth-cohort 2010). We estimated PCV program effectiveness and its impact on S. pneumoniae diseases. PCV EFFECTIVENESS: We used the screening method. We calculated the Proportion of Population Vaccinated from immunization registries and detected cases through a laboratory-confirmed surveillance among hospitalized children≤60 months. A confirmed IPD case was a child with PCR positive for S. pneumoniae. Differences among children were assessed with the Chi-square or the Fisher exact test (P value<0.05). PCV IMPACT: We constructed time series using outcome-specific Poisson regression models: hospitalization rate in pre-PCV era and hospitalization risk ratios (RRs) with 95% CIs for both PCV7 and PCV7/PCV13 shifting era. We calculated hospitalization RR with 95% CIs comparing pre-PCV years with vaccination period. The PCV effectiveness was 84.3% (95% CI: 84.0-84.6%). In May 2010-January 2013, we enrolled 159 suspected IPD of whom 4 were confirmed. Two (fully vaccinated) were caused by serotype 9V, 1 (not vaccinated) by serotype 3, 1 (vaccinated with 2 PCV13 doses) by 15B/C. The most important reduction was for pneumococcal pneumonia (RR: 0.43, 95% CI: 0.21-0.90). The PCV program show promising results in terms of both PCV13 effectiveness and its impact in reducing IPD in children<5 years.
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Affiliation(s)
- Domenico Martinelli
- Department of Medical and Surgical Sciences; University of Foggia; Foggia, Italy
| | - Biagio Pedalino
- Department of Medical and Surgical Sciences; University of Foggia; Foggia, Italy
| | - Maria Giovanna Cappelli
- Department of Biomedical Sciences and Human Oncology; University of Bari Aldo Moro; Bari, Italy
| | - Giovanni Caputi
- Prevention Department; Taranto Local Health Unit; Taranto, Italy
| | - Anna Sallustio
- Department of Biomedical Sciences and Human Oncology; University of Bari Aldo Moro; Bari, Italy
| | - Francesca Fortunato
- Department of Medical and Surgical Sciences; University of Foggia; Foggia, Italy
| | - Silvio Tafuri
- Department of Biomedical Sciences and Human Oncology; University of Bari Aldo Moro; Bari, Italy
| | - Vanessa Cozza
- Department of Medical and Surgical Sciences; University of Foggia; Foggia, Italy; European Programme for Intervention Epidemiology Training (EPIET); European Centre for Disease Prevention and Control (ECDC); Stockholm, Sweden
| | - Cinzia Germinario
- Department of Biomedical Sciences and Human Oncology; University of Bari Aldo Moro; Bari, Italy
| | - Maria Chironna
- Department of Biomedical Sciences and Human Oncology; University of Bari Aldo Moro; Bari, Italy
| | - Rosa Prato
- Department of Medical and Surgical Sciences; University of Foggia; Foggia, Italy
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Mousavi SF, Nobari S, Ghezelgeh FR, Lyriai H, Jalali P, Shahcheraghi F, Oskoui M. Serotyping of Streptococcus pneumoniae isolated from Tehran by Multiplex PCR: Are serotypes of clinical and carrier isolates identical? IRANIAN JOURNAL OF MICROBIOLOGY 2013; 5:220-6. [PMID: 24475327 PMCID: PMC3895558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND AND OBJECTIVES Streptococcus pneumoniae is the most common cause of invasive infections among both young children and elderly people. Common serotypes causing invasive diseases and the emergence of carriers of Streptococcus pneumoniae in Iran is not yet known. Past-vaccine surveillance studies of serotype prevalence patterns in Iran are necessary to monitor the epidemiology of Streptococcus pneumoniae. Because of variation of pneumococcal serotypes in different geographical regions, in this study we evaluated common serotypes causing pneumococcal infections and healthy carrier children in Tehran by Multiplex PCR. MATERIALS AND METHODS A total of 150 nasopharyngeal swabs were collected from healthy children in Tehran between December 2011 and August a2012, and 100 clinical samples were collected. Identification was performed by biochemical and molecular tests. Serotyping was done by multiplex PCR. We designed primers based on the sequences available for the routine capsular types and combined them into six multiplex PCR. RESULTS From 150 nasopharyngeal swabs, 40 isolates of Streptococcus pneumoniae were identified after identification tests. Thirty six clinical isolates were also detected among clinical samples. Four serotypes (19A, 6, 3, 23F) of S. pneumoniae accounted for 55.7% of both sets of strains isolated from nasal carriage and clinical samples. Serotype 19A was the most common serotype among both groups. CONCLUSION The multiplex PCR approach was successfully adapted to identify serotypes from more than 91% of the isolates tested. Among S. pneumoniae isolates in Tehran, the most prevalent serotypes were similar among carriage and invasive isolates. Continued monitoring of common serotypes of Streptococcus pneumoniae is essential for future vaccine formulation in Iran.
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Affiliation(s)
- Seyed Fazlollah Mousavi
- Corresponding author: Seyed Fazlollah Mousavi, PhD, Address: Department of Bacteriology & Microbiology Research Center, Pasteur Institute of Iran, 69, Pasteur Ave. 13164, Tehran, Iran. Tel: +98-21-66405535. E-mail:
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Oliver MB, van der Linden MPG, Küntzel SA, Saad JS, Nahm MH. Discovery of Streptococcus pneumoniae serotype 6 variants with glycosyltransferases synthesizing two differing repeating units. J Biol Chem 2013; 288:25976-25985. [PMID: 23897812 DOI: 10.1074/jbc.m113.480152] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Streptococcus pneumoniae is a persistent, opportunistic commensal of the human nasopharynx and is the leading cause of community-acquired pneumonia. It expresses an anti-phagocytic capsular polysaccharide (PS). Genetic variation of the capsular PS synthesis (cps) locus is the molecular basis for structural and antigenic heterogeneity of capsule types (serotypes). Serogroup 6 has four known members (6A-6D) with distinct serologic properties, homologous cps loci, and structurally similar PSs. cps of serotypes 6A/6B have wciNα, encoding α-1,3-galactosyltransferase, whereas serotypes 6C/6D have wciNβ encoding α-1,3-glucosyltransferase. Two atypical serogroup 6 isolates (named 6X11 and 6X12) have been discovered recently in Germany. Flow cytometric studies using monoclonal antibodies show that 6X11 has serologic properties of 6B/6D, whereas 6X12 has 6A/6C. NMR studies of their capsular PSs revealed that 6X11 and 6X12 have two different repeating units with a distribution of ~40:60 6B:6D and 75:25 6A:6C PS, respectively. Sequencing of the wciNα gene in 6X12 and 6X11 revealed single and double nucleotide substitutions, respectively, resulting in the amino acid changes A150T and D38N. Substitution of alanine with threonine at position 150 in a 6A strain was associated with hybrid serologic and chemical profiles like 6X12. The hybrid serotypes represented by 6X12 and 6X11 strains are now named serotypes 6F and 6G. Single amino acid changes in cps genes encoding glycosyltransferases can alter substrate specificities, permit biosynthesis of heterogeneous capsule repeating units, and result in new hybrid capsule types that may differ in their interaction with the immune system of the host.
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Affiliation(s)
- Melissa B Oliver
- Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294 and
| | - Mark P G van der Linden
- the Department of Medical Microbiology, German National Reference Center for Streptococci, University Hospital Rheinisch-Westfälische Technische Hochschule, D-52074 Aachen, Germany
| | - Sharon A Küntzel
- the Department of Medical Microbiology, German National Reference Center for Streptococci, University Hospital Rheinisch-Westfälische Technische Hochschule, D-52074 Aachen, Germany
| | | | - Moon H Nahm
- Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294 and; From the Departments of Microbiology and.
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Capsular gene sequences and genotypes of "serotype 6E" Streptococcus pneumoniae isolates. J Clin Microbiol 2013; 51:3395-9. [PMID: 23824778 DOI: 10.1128/jcm.01645-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To characterize Streptococcus pneumoniae "serotype 6E," complete cps loci were sequenced. The capsular genes of "serotype 6E" isolates differed much from those of serotypes 6A and 6B. We identified 10 additional "serotype 6E" isolates, which are not confined to a restricted geographic locality. Most of these "serotype 6E" isolates belonged to sequence type 90 and its single-locus variants. The homogeneity of their genetic background and cps loci suggests a recent origin of the "serotype 6E" isolates.
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Loman NJ, Gladstone RA, Constantinidou C, Tocheva AS, Jefferies JMC, Faust SN, O’Connor L, Chan J, Pallen MJ, Clarke SC. Clonal expansion within pneumococcal serotype 6C after use of seven-valent vaccine. PLoS One 2013; 8:e64731. [PMID: 23724086 PMCID: PMC3665553 DOI: 10.1371/journal.pone.0064731] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/17/2013] [Indexed: 12/29/2022] Open
Abstract
Streptococcus pneumoniae causes invasive infections, primarily at the extremes of life. A seven-valent conjugate vaccine (PCV7) is used to protect against invasive pneumococcal disease in children. Within three years of PCV7 introduction, we observed a fourfold increase in serotype 6C carriage, predominantly due to a single clone. We determined the whole-genome sequences of nineteen S. pneumoniae serotype 6C isolates, from both carriage (n = 15) and disease (n = 4) states, to investigate the emergence of serotype 6C in our population, focusing on a single multi-locus sequence type (MLST) clonal complex 395 (CC395). A phylogenetic network was constructed to identify different lineages, followed by analysis of variability in gene sets and sequences. Serotype 6C isolates from this single geographical site fell into four broad phylogenetically distinct lineages. Variation was seen in the 6C capsular locus and in sequences of genes encoding surface proteins. The largest clonal complex was characterised by the presence of lantibiotic synthesis locus. In our population, the 6C capsular locus has been introduced into multiple lineages by independent capsular switching events. However, rapid clonal expansion has occurred within a single MLST clonal complex. Worryingly, plasticity exists within current and potential vaccine-associated loci, a consideration for future vaccine use, target selection and design.
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Affiliation(s)
- Nicholas J. Loman
- Centre for Systems Biology, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Rebecca A. Gladstone
- Molecular Microbiology Group, Sir Henry Wellcome Laboratories, Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Chrystala Constantinidou
- Division of Microbiology and Infection, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Anna S. Tocheva
- Molecular Microbiology Group, Sir Henry Wellcome Laboratories, Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Johanna M. C. Jefferies
- Molecular Microbiology Group, Sir Henry Wellcome Laboratories, Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- Southampton NIHR, Respiratory Biomedical Research Unit, University Hospital Southampton Foundation NHS Trust, Southampton, United Kingdom
| | - Saul N. Faust
- Molecular Microbiology Group, Sir Henry Wellcome Laboratories, Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- NIHR, Wellcome Trust Clinical Research Facility, University Hospital Southampton Foundation NHS Trust, Southampton, United Kingdom
- Southampton NIHR, Respiratory Biomedical Research Unit, University Hospital Southampton Foundation NHS Trust, Southampton, United Kingdom
| | - Leigh O’Connor
- Centre for Systems Biology, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Jacqueline Chan
- Division of Microbiology and Infection, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Mark J. Pallen
- Division of Microbiology and Infection, Warwick Medical School, University of Warwick, Coventry, United Kingdom
- * E-mail:
| | - Stuart C. Clarke
- Molecular Microbiology Group, Sir Henry Wellcome Laboratories, Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
- Health Protection Agency, Southampton, United Kingdom
- Southampton NIHR, Respiratory Biomedical Research Unit, University Hospital Southampton Foundation NHS Trust, Southampton, United Kingdom
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Roles of virulence genes (PsaA and CpsA) on the invasion of Streptococcus pneumoniae into blood system. Eur J Med Res 2013; 18:14. [PMID: 23683724 PMCID: PMC3695859 DOI: 10.1186/2047-783x-18-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 04/25/2013] [Indexed: 12/02/2022] Open
Abstract
Background Streptococcus pneumoniae (SP) is the major cause of childhood mortality worldwide, we need to understand virulence genes of SP so can better target the treatment. We investigated the expression of virulence genes PsaA and CpsA in different strains of SP interacting with monocyte cell line (THP-1) or pneumocyte cell line (A549) and the possible mechanism of SP invasion of the blood system. Methods A total of 23 strains of SP were collected from hospitalized patients (blood-derived and sputum-derived) in the Second Affiliated Hospital of Wenzhou Medical College. The strains and ATCC 49619 were cultured, and RNAs were extracted. THP-1 and A549 cells were stimulated by different SP and ATCC 49619 for 4 h and 8 h, respectively. Quantitative real-time PCR was used to analyze the mRNA expression of PsaA and CpsA. The data were analyzed by SPSS 17.0. Results The mRNA level of PsaA and CpsA were all significantly increased in clinical SP strains when compared to ATCC49619 after tedTHP-1 and A549 cells were stimulated. Clinical SPs showed higher virulence compared with ATCC49619. Conclusions The expression of CpsA is the basis of the pathogenicity of SP. The expression of virulence gene PsaA may be helpful to the invasion of SP to the blood system.
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van der Linden M, Winkel N, Küntzel S, Farkas A, Perniciaro SR, Reinert RR, Imöhl M. Epidemiology of Streptococcus pneumoniae serogroup 6 isolates from IPD in children and adults in Germany. PLoS One 2013; 8:e60848. [PMID: 23593324 PMCID: PMC3621884 DOI: 10.1371/journal.pone.0060848] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 03/03/2013] [Indexed: 11/18/2022] Open
Abstract
This study presents serogroup 6 isolates from invasive pneumococcal disease (IPD) before and after the recommendation for childhood pneumococcal conjugate vaccination in Germany (July 2006). A total of 19,299 (children: 3508, adults: 15,791) isolates were serotyped. Serogroup 6 isolates accounted for 9.5% (children) and 6.7% (adults), respectively. 548 isolates had serotype 6A, 558 had serotype 6B, 285 had serotype 6C, and 4 had serotype 6D. Among children, serotype 6B was most prevalent (7.5% of isolates) before vaccination, followed by 6A and 6C. After the 7-valent pneumococcal conjugate vaccine (PCV7), the prevalence of serotype 6B significantly decreased (p = 0.040), a pattern which continued in the higher-valent PCV period (PCV10, PCV13). Serotype 6A prevalence showed a slight increase directly after the start of PCV7 vaccination, followed by a decrease which continued throughout the PCV10/13 period. Serotype 6C prevalence remained low. Serotype 6D was not found among IPD isolates from children. Among adults, prevalence of both 6A and 6B decreased, with 6B reaching statistical significance (p = 0.045) and 6A showing a small increase in 2011–2012. Serotype 6C prevalence was 1.5% or lower before vaccination, but increased post-vaccination to 3.6% in 2011/12 (p = 0.031). Four serotype 6D isolates were found post-PCV7 childhood vaccination, and two post-PCV10/13. Antibiotic resistance was found mainly in serotype 6B; serotype 6A showed lower resistance rates. Serotype 6C isolates only showed resistance among adults; serotype 6D isolates showed no resistance. Multilocus sequence typing showed that sequence type (ST) 1692 was the most prevalent serotype 6C clone. Thirty-two other STs were found among serotype 6C isolates, of which 12 have not been previously reported. The four serotype 6D isolates had ST 948, ST 2185 and two new STs: 8422 and 8442. Two serogroup 6 isolates could not be assigned to a serotype, but had STs common to serogroup 6.
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Affiliation(s)
- Mark van der Linden
- National Reference Center for Streptococci, Department of Medical Microbiology, University Hospital (RWTH), Aachen, Germany.
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Genetic analysis of capsular polysaccharide synthesis gene clusters from all serotypes of Streptococcus suis: potential mechanisms for generation of capsular variation. Appl Environ Microbiol 2013; 79:2796-806. [PMID: 23416996 DOI: 10.1128/aem.03742-12] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis strains are classified into 35 serotypes on the basis of the antigenicity of their capsular polysaccharides (CPs). CP synthesis genes are known to be clustered on the chromosome (cps gene cluster). The entire cps gene clusters of S. suis have so far been sequenced in 15 serotypes and found to be located between orfZ and aroA. In this study, to provide comprehensive information about S. suis CPs, we sequenced the entire cps gene clusters of the remaining serotypes and analyzed the complete set of S. suis cps gene clusters. Among the 35 cps gene clusters, 22 were located between orfZ and aroA, whereas the other 13 were flanked by other gene(s) on the chromosomes, and the chromosomal locus was classified into five patterns. By clustering analysis, the predicted products of cps genes found in the 35 serotypes were assigned into 291 homology groups, and all serotypes possessed a serotype-specific gene, except for serotypes 1, 2, 1/2, and 14. Because of the presence of genes encoding flippase (wzx) and polymerase (wzy), CPs of all serotypes were thought to be synthesized by the Wzx/Wzy pathway. Our data also implied the possibility of the transfer of the entire or partial cps gene clusters among S. suis strains, as well as the influence of spontaneous mutations in a single gene or a few genes on the antigenicity of some serotypes. Accumulation of these gene transfers and small-scale mutations may have generated the antigenic diversity of S. suis CPs.
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Wyres KL, Lambertsen LM, Croucher NJ, McGee L, von Gottberg A, Liñares J, Jacobs MR, Kristinsson KG, Beall BW, Klugman KP, Parkhill J, Hakenbeck R, Bentley SD, Brueggemann AB. Pneumococcal capsular switching: a historical perspective. J Infect Dis 2012; 207:439-49. [PMID: 23175765 PMCID: PMC3537446 DOI: 10.1093/infdis/jis703] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Background.Changes in serotype prevalence among pneumococcal populations result from both serotype replacement and serotype (capsular) switching. Temporal changes in serotype distributions are well documented, but the contribution of capsular switching to such changes is unknown. Furthermore, it is unclear to what extent vaccine-induced selective pressures drive capsular switching. Methods.Serotype and multilocus sequence typing data for 426 pneumococci dated from 1937 through 2007 were analyzed. Whole-genome sequence data for a subset of isolates were used to investigate capsular switching events. Results.We identified 36 independent capsular switch events, 18 of which were explored in detail with whole-genome sequence data. Recombination fragment lengths were estimated for 11 events and ranged from approximately 19.0 kb to ≥58.2 kb. Two events took place no later than 1960, and the imported DNA included the capsular locus and the nearby penicillin-binding protein genes pbp2x and pbp1a. Conclusions.Capsular switching has been a regular occurrence among pneumococcal populations throughout the past 7 decades. Recombination of large DNA fragments (>30 kb), sometimes including the capsular locus and penicillin-binding protein genes, predated both vaccine introduction and widespread antibiotic use. This type of recombination has likely been an intrinsic feature throughout the history of pneumococcal evolution.
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Affiliation(s)
- Kelly L Wyres
- Department of Zoology, University of Oxford, Oxford, United Kingdom
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McEllistrem MC, Nahm MH. Novel pneumococcal serotypes 6C and 6D: anomaly or harbinger. Clin Infect Dis 2012; 55:1379-86. [PMID: 22903767 DOI: 10.1093/cid/cis691] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Clinical use of the 7-valent pneumococcal protein conjugate (PCV7) vaccine, which includes serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F, dramatically reduced invasive pneumococcal disease (IPD); however, the effectiveness was diminished due to serotype shift. Although shift due to known serotypes was anticipated, shift by misidentified serotypes was unexpected. We describe the experience with newly recognized serotypes 6C and 6D, which were mistyped as serotypes 6A and 6B, respectively. Although serotype 6D caused only occasional infections, IPD due to serotype 6C disease expanded in the PCV7 era. Subsequent studies showed that PCV7 provided cross-protection against serotype 6A but not serotype 6C. The 13-valent pneumococcal protein conjugate (PCV13) vaccine, which includes PCV7 serotypes plus serotypes 1, 3, 5, 6A, 7F, 19A, may provide protection against IPD due to serotypes 6C and 6D. Regardless, this narrative illustrates the potential impact of unrecognized serotypes on the efficacy of a serotype-specific vaccine.
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Calix JJ, Porambo RJ, Brady AM, Larson TR, Yother J, Abeygunwardana C, Nahm MH. Biochemical, genetic, and serological characterization of two capsule subtypes among Streptococcus pneumoniae Serotype 20 strains: discovery of a new pneumococcal serotype. J Biol Chem 2012; 287:27885-94. [PMID: 22736767 DOI: 10.1074/jbc.m112.380451] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The bacterial pathogen Streptococcus pneumoniae expresses one of over 90 structurally distinct polysaccharide (PS) capsule serotypes. Prior PS structural analyses of the vaccine-associated serotype 20 do not agree with reports describing the genes that mediate capsule synthesis. Furthermore, using immunized human sera-based assays, serological differences were recently noted among strains typed as serotype 20. We examined the capsule structures of two serologically dissimilar serotype 20 strains, 20α and 20β, by extensive biochemical analysis. 20α PS was composed of the previously described serotype 20 hexasaccharide repeat unit, whereas the 20β PS was composed of a novel heptasaccharide repeat unit containing an extra branching α-glucose residue. Genetic analysis of the subtypes revealed that 20α may have arisen from a 20β progenitor following loss of function mutation to the glycosyltransferase gene whaF. Conventional serotyping methods using rabbit polyclonal or mouse monoclonal antibodies were unable to distinguish the subtypes. However, genetic analysis of multiple "serotype 20" clinical isolates revealed that all strains contain the 20β genotype. We propose naming bacteria that express the previously described 20α capsule structure 20A and bacteria that express the novel 20β capsule structure 20B, a new pneumococcal serotype.
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Affiliation(s)
- Juan J Calix
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Multidrug-resistant Streptococcus pneumoniae serotype 6D clones in South Korea. J Clin Microbiol 2011; 50:818-22. [PMID: 22170935 DOI: 10.1128/jcm.05895-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To investigate the characteristics of main Streptococcus pneumoniae clones of serotype 6D (ST282 and ST3171) in South Korea, antimicrobial susceptibility testing was performed, and 11 genes around the cps locus were sequenced on ST282(6D), ST3171(6D), and ST81(6A) isolates. The antimicrobial susceptibility patterns were very similar between clones belonging to the same clonal complex, ST81(6A) and ST282(6D); nonsusceptibilities to penicillin and cefuroxime, high MICs of ceftriaxone, and high resistance rates to trimethoprim-sulfamethoxazole. However, ST3171(6D) isolates showed resistance to only macrolides and clindamycin. The sequences of 11 genes around the cps locus indicated the same genetic backgrounds between the ST81(6A) and ST282(6D) isolates. On the other hand, ST3171(6D) isolates showed nucleotide and amino acid differences from ST81(6A) and ST282(6D) isolates in most genes, indicating a different genetic background. The mosaic structure of dexB gene in ST282(6D) isolates indicated that recombination might occur in the dexB gene. Our results suggest that the multidrug-resistant ST282(6D) pneumococcal clone has emerged by serial genetic recombination, including capsular switch.
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Sequence diversity within the capsular genes of Streptococcus pneumoniae serogroup 6 and 19. PLoS One 2011; 6:e25018. [PMID: 21949837 PMCID: PMC3174988 DOI: 10.1371/journal.pone.0025018] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 08/22/2011] [Indexed: 11/30/2022] Open
Abstract
The main virulence factor of Streptococcus pneumoniae is the capsule. The polysaccharides comprising this capsule are encoded by approximately 15 genes and differences in these genes result in different serotypes. The aim of this study was to investigate the sequence diversity of the capsular genes of serotypes 6A, 6B, 6C, 19A and 19F and to explore a possible effect of vaccination on variation and distribution of these serotypes in the Netherlands. The complete capsular gene locus was sequenced for 25 serogroup 6 and for 20 serogroup 19 isolates. If one or more genes varied in 10 or more base pairs from the reference sequence, it was designated as a capsular subtype. Allele-specific PCRs and specific gene sequencing of highly variable capsular genes were performed on 184 serogroup 6 and 195 serogroup 19 isolates to identify capsular subtypes. This revealed the presence of 6, 3 and a single capsular subtype within serotypes 6A, 6B and 6C, respectively. The serotype 19A and 19F isolates comprised 3 and 4 capsular subtypes, respectively. For serogroup 6, the genetic background, as determined by multi locus sequence typing (MLST) and multiple- locus variable number of tandem repeat analysis (MLVA), seemed to be closely related to the capsular subtypes, but this was less pronounced for serogroup 19 isolates. The data also suggest shifts in the occurrence of capsular subtypes within serotype 6A and 19A after introduction of the 7-valent pneumococcal vaccine. The shifts within these non-vaccine serotypes might indicate that these capsular subtypes are filling the niche of the vaccine serotypes. In conclusion, there is considerable DNA sequence variation of the capsular genes within pneumococcal serogroup 6 and 19. Such changes may result in altered polysaccharides or in strains that produce more capsular polysaccharides. Consequently, these altered capsules may be less sensitive for vaccine induced immunity.
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Abstract
BACKGROUND Vaccination against 7 serotypes of Streptococcus pneumoniae has led to the near extinction of vaccine serotypes in both disease and asymptomatic carriage. In carriage, vaccine serotypes have been replaced by nonvaccine serotypes. METHODS We used multilocus sequence typing to analyze a sample of 294 isolates of S. pneumoniae carried by Massachusetts children (aged, 3 months-7 years) and examine the results for serotype switching and association with antimicrobial resistance. RESULTS Eighty-six distinct sequence types (STs) were found, 10 of which exhibited a serotype other than that which would be expected from previous carriage samples. We interpret this as evidence of past or recent serotype switching. Switched variants include ST 320, which is a common and increasing source of multidrug resistance in this community. Switching events within serogroups were more common than expected by chance (P = 0.043 by a Monte Carlo approach). Using multilocus sequence typing data and eBURST analysis, we also describe clonal dynamics within the important replacement serotypes 19A, 15B/C, 35B, and the recently described 6C. CONCLUSIONS Some strains generated by serotype switching are increasingly important parts of the carriage population. In the case of 19A, it appears that the majority of increase is due to ST 320, a recently reported switched variant. This may have consequences for the STs causing invasive pneumococcal disease.
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The prevalence and characteristics of Streptococcus pneumoniae isolates expressing serotypes 6C and 6D in Hong Kong prior to the introduction of the 7-valent pneumococcal conjugate vaccine. Diagn Microbiol Infect Dis 2011; 68:439-44. [PMID: 20926218 DOI: 10.1016/j.diagmicrobio.2010.07.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/24/2010] [Accepted: 07/26/2010] [Indexed: 11/23/2022]
Abstract
A study was conducted to determine the prevalence of the 2 newly described types, 6C and 6D, among pneumococcal isolates collected in Hong Kong before availability of the 7-valent pneumococcal conjugate vaccine. A total of 154 serogroup 6 isolates obtained from nasopharynx (n = 106), blood (n = 22), respiratory (n = 24), and cerebrospinal fluid (CSF) (n = 2) during 1995 to 2001 were analyzed by polymerase chain reaction typing. Five nasopharyngeal and 2 sputum isolates were found to belong to 6C and 6D, respectively. The isolates were genetically diverse, but one 6C and two 6D isolates exhibited some clonal relationship. Phylogenetic analysis of the wchA-wciN(β)-wciO nucleotide sequences showed that the Hong Kong 6C/6D isolates had 2 allelic profiles, which were more closely related to 6C/6D isolates from Fijian and Korea than were those from Brazil and the United States. However, all of the wciP gene sequences for both Hong Kong and non-Hong Kong isolates clustered together: 6C isolates with the wciP-9 allele and 6D isolates with the wciP-5 allele. In conclusion, the prevalence of the 2 newly described serotypes was low before the era of the pneumococcal conjugate vaccine. Nonetheless, results from the molecular studies indicated that the evolution of the capsular genes have involved complex pathways.
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Comparison of capsular genes of Streptococcus pneumoniae serotype 6A, 6B, 6C, and 6D isolates. J Clin Microbiol 2011; 49:1758-64. [PMID: 21411593 DOI: 10.1128/jcm.02628-10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recently, Streptococcus pneumoniae serotypes 6C and 6D have been identified. It is thought that they emerged by the replacement of wciN(β) in the capsular loci of serotypes 6A and 6B, respectively. However, their evolution has not been unveiled yet. To investigate the evolution of four serotypes of S. pneumoniae serogroup 6, four genes of the capsular polysaccharide synthesis (cps) locus, wchA, wciN, wciO, and wciP, of isolates of S. pneumoniae serotypes 6A, 6B, 6C, and 6D were sequenced. Multilocus sequence typing (MLST) was performed to investigate their genetic backgrounds. The wchA gene of serotype 6C and 6D isolates was distinct from that of serotype 6A and 6B isolates, which may suggest cotransfer of wchA with wciN(β). Otherwise, serotypes 6C and 6D displayed different genetic backgrounds from serotypes 6A and 6B, which was suggested by MLST analysis. In addition, serotype 6C isolates showed distinct wciP polymorphisms from other serotypes, which also indicated that serotype 6C had not recently originated from serotype 6A. Although serotype 6D shared the same amino acid polymorphisms of wciO with serotype 6B, wciP of serotype 6D differed from that of serotype 6B. The data indicate the implausibility of the scenario of a recent emergence of the cps locus of serotype 6D by genetic recombination between serotypes 6B and 6C. In addition, five serotype 6A and 6B isolates (6X group) displayed cps loci distinct from those of other isolates. The cps locus homogeneity and similar sequence types in MLST analysis suggest that most of the 6X group of isolates originated from the same ancestor and that the entire cps locus might have recently been transferred from an unknown origin. Serotype 6B isolates showed two or more cps locus subtypes, indicating a recombination-mediated mosaic structure of the cps locus of serotype 6B. The collective data favor the emergence of cps loci of serotypes 6A, 6B, 6C, and 6D by complicated recombination.
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