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Børud B, Koomey M. Sweet complexity: O-linked protein glycosylation in pathogenic Neisseria. Front Cell Infect Microbiol 2024; 14:1407863. [PMID: 38808060 PMCID: PMC11130364 DOI: 10.3389/fcimb.2024.1407863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 04/29/2024] [Indexed: 05/30/2024] Open
Abstract
The genus Neisseria, which colonizes mucosal surfaces, includes both commensal and pathogenic species that are exclusive to humans. The two pathogenic Neisseria species are closely related but cause quite different diseases, meningococcal sepsis and meningitis (Neisseria meningitidis) and sexually transmitted gonorrhea (Neisseria gonorrhoeae). Although obvious differences in bacterial niches and mechanisms for transmission exists, pathogenic Neisseria have high levels of conservation at the levels of nucleotide sequences, gene content and synteny. Species of Neisseria express broad-spectrum O-linked protein glycosylation where the glycoproteins are largely transmembrane proteins or lipoproteins localized on the cell surface or in the periplasm. There are diverse functions among the identified glycoproteins, for example type IV biogenesis proteins, proteins involved in antimicrobial resistance, as well as surface proteins that have been suggested as vaccine candidates. The most abundant glycoprotein, PilE, is the major subunit of pili which are an important colonization factor. The glycans attached can vary extensively due to phase variation of protein glycosylation (pgl) genes and polymorphic pgl gene content. The exact roles of glycosylation in Neisseria remains to be determined, but increasing evidence suggests that glycan variability can be a strategy to evade the human immune system. In addition, pathogenic and commensal Neisseria appear to have significant glycosylation differences. Here, the current knowledge and implications of protein glycosylation genes, glycan diversity, glycoproteins and immunogenicity in pathogenic Neisseria are summarized and discussed.
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Affiliation(s)
- Bente Børud
- Department of Bacteriology, Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Michael Koomey
- Department of Biosciences, Section for Genetics and Evolutionary Biology, University of Oslo, Oslo, Norway
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2
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McMillan M, Mohammed H, Bednarz J, Leong LEX, Lawrence A, Sullivan TR, Maiden MCJ, Marshall HS. Longitudinal study of meningococcal carriage in adolescents and young adults in South Australia 2017-2020. J Infect 2024; 88:149-157. [PMID: 38242365 DOI: 10.1016/j.jinf.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/15/2023] [Accepted: 01/12/2024] [Indexed: 01/21/2024]
Abstract
BACKGROUND This analysis investigated longitudinal changes in meningococcal carriage in adolescents in South Australia over 4 years. METHODS Data from the "B Part of It" study, which included a state-wide cluster randomized controlled trial in secondary-school students (n = 34,489 in 2017 and 2018) and serial cross-sectional studies in school leavers aged 17-25 years (n = 4028 in 2019-2020). Individuals had oropharyngeal swabs collected annually. This study included two unique cohorts: (1) individuals enrolled in 2019, with three consecutive annual swabs taken in 2017, 2018 and 2019; and (2) individuals enrolled in 2020, with swabs taken in 2017, 2018, and 2020. Disease-associated N. meningitidis genogroups were identified using PCR and whole genome sequencing. Univariate analysis identified risk factors for recurrent carriage (≥2). RESULTS Among school leavers, 50 (1.7%, total n = 2980) had carriage detected at successive visits. In participants with meningococcal carriage at successive visits, 38/50 (76.0%) had the same genogroup detected by porA PCR. Of those, 19 had the same MLST type and demonstrated minimal variation, indicating they most likely had sustained carriage of the same isolate (range 226 to 490 days, mean duration 352 [SD 51] days). In the 2019 school leaver cohort, 6.7% acquired carriage in their first year out of school compared to 3.3% in their final school year. Compared to single carriage detection, recurrent carriage was potentially more likely in older adolescents (16 compared to ≤15 years; OR = 1.97 (95%CI 1.0, 3.86); p = 0.048). CONCLUSION Whilst carriage is typically transient, some adolescents/young adults may have persistent carriage and are likely to be an important group in the transmission of meningococci.
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Affiliation(s)
- Mark McMillan
- Vaccinology and Immunology Research Trials Unit, Women's and Children's Health Network, Adelaide, South Australia, Australia; Robinson Research Institute and Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Hassen Mohammed
- Vaccinology and Immunology Research Trials Unit, Women's and Children's Health Network, Adelaide, South Australia, Australia; Robinson Research Institute and Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Jana Bednarz
- School of Public Health, University of Adelaide, Adelaide, South Australia, Australia; SAHMRI Women and Kids Theme, South Australia Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Lex E X Leong
- Microbiology and Infectious Diseases, SA Pathology, Adelaide 5000, Australia
| | - Andrew Lawrence
- Robinson Research Institute and Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia; Microbiology and Infectious Diseases, SA Pathology, Adelaide 5000, Australia
| | - Thomas R Sullivan
- School of Public Health, University of Adelaide, Adelaide, South Australia, Australia; SAHMRI Women and Kids Theme, South Australia Health and Medical Research Institute, Adelaide, South Australia, Australia
| | | | - Helen S Marshall
- Vaccinology and Immunology Research Trials Unit, Women's and Children's Health Network, Adelaide, South Australia, Australia; Robinson Research Institute and Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.
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3
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Mikucki A, Kahler CM. Microevolution and Its Impact on Hypervirulence, Antimicrobial Resistance, and Vaccine Escape in Neisseria meningitidis. Microorganisms 2023; 11:3005. [PMID: 38138149 PMCID: PMC10745880 DOI: 10.3390/microorganisms11123005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/07/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023] Open
Abstract
Neisseria meningitidis is commensal of the human pharynx and occasionally invades the host, causing the life-threatening illness invasive meningococcal disease. The meningococcus is a highly diverse and adaptable organism thanks to natural competence, a propensity for recombination, and a highly repetitive genome. These mechanisms together result in a high level of antigenic variation to invade diverse human hosts and evade their innate and adaptive immune responses. This review explores the ways in which this diversity contributes to the evolutionary history and population structure of the meningococcus, with a particular focus on microevolution. It examines studies on meningococcal microevolution in the context of within-host evolution and persistent carriage; microevolution in the context of meningococcal outbreaks and epidemics; and the potential of microevolution to contribute to antimicrobial resistance and vaccine escape. A persistent theme is the idea that the process of microevolution contributes to the development of new hyperinvasive meningococcal variants. As such, microevolution in this species has significant potential to drive future public health threats in the form of hypervirulent, antibiotic-resistant, vaccine-escape variants. The implications of this on current vaccination strategies are explored.
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Affiliation(s)
- August Mikucki
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA 6009, Australia;
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia
| | - Charlene M. Kahler
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA 6009, Australia;
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia
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4
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Næss LM, Maugesten IS, Caugant DA, Kassu A, Aseffa A, Børud B. Genetic, Functional, and Immunogenic Analyses of the O-Linked Protein Glycosylation System in Neisseria meningitidis Serogroup A ST-7 Isolates. J Bacteriol 2023; 205:e0045822. [PMID: 36852982 PMCID: PMC10029716 DOI: 10.1128/jb.00458-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/02/2023] [Indexed: 03/01/2023] Open
Abstract
Neisseria meningitidis exhibits a general O-linked protein glycosylation system in which pili and other extracytoplasmic proteins are glycosylated. To investigate glycan antigenicity in humans and the significance of high glycan diversity on immune escape mechanisms, we exploited serogroup A meningococcal strains and serum samples obtained from laboratory-confirmed Ethiopian patients with meningococcal disease. The 37 meningococcal isolates were sequenced, and their protein glycosylation (pgl) genotypes and protein glycosylation phenotypes were investigated in detail. An insertion sequence (IS1655) element in pglH reduced glycan variability in the majority of isolates, while phase variation strengthened glycan variability and microheterogeneity. Homologous recombination events within the pgl genes were identified in eight of the 37 isolates, and the phenotypic consequences ranged from none detected to altered glycoforms in two of the isolates in which the whole pgl locus was exchanged. Immunoblotting of sera against a complete panel of glycan-expressing mutant strains demonstrated that most of these patient sera had IgG antibodies against various neisserial protein glycan antigens. Furthermore, using a bactericidal assay comparing a wild-type meningococcal A strain and a glycosylation-null variant strain, we showed that these protein glycan antigens interfere with bactericidal killing by antibodies in patient sera. Altogether, we were largely able to link pgl genotype with glycosylation phenotype. Our study reveals that protein glycans seem to contribute to the ability of N. meningitidis to resist the bactericidal activity of human serum, possibly by masking protein epitopes important for bactericidal killing and thus protection against meningococcal disease. IMPORTANCE Bacterial meningitis is a serious global health problem, and one of the major causative organisms is Neisseria meningitidis. Extensive variability in protein glycan structure and antigenicity is due to phase variation of protein glycosylation genes and polymorphic gene content and function. The exact role(s) of glycosylation in Neisseria remains to be determined, but increasing evidence, supported by this study, suggests that glycan variability can be a strategy to escape the human immune system. The complexity of the O-linked protein glycosylation system requires further studies to fully comprehend how these bacteria utilize variation in pgl genes to produce such high glycoform diversity and to evade the human immune response.
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Affiliation(s)
- Lisbeth M. Næss
- Division of Infection Control, Norwegian Institute of Public Health, Oslo, Norway
| | - Ingunn S. Maugesten
- Division of Infection Control, Norwegian Institute of Public Health, Oslo, Norway
| | - Dominique A. Caugant
- Division of Infection Control, Norwegian Institute of Public Health, Oslo, Norway
- Department of Community Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Afework Kassu
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Abraham Aseffa
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Bente Børud
- Division of Infection Control, Norwegian Institute of Public Health, Oslo, Norway
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5
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Grote A, Earl AM. Within-host evolution of bacterial pathogens during persistent infection of humans. Curr Opin Microbiol 2022; 70:102197. [PMID: 36063686 DOI: 10.1016/j.mib.2022.102197] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/26/2022] [Accepted: 07/28/2022] [Indexed: 01/25/2023]
Abstract
Many bacterial pathogens can form persistent infections, providing an infectious reservoir, which allows for infection of new hosts. Currently, the molecular mechanisms and evolutionary dynamics driving persistence are still not well-understood. High-throughput sequencing methods have enabled the study of within-host evolution of persistent bacterial pathogens, revealing common trends among bacterial species in how they adapt to persist. We will focus on trends emerging from longitudinal human-cohort studies, including i) genome-size reduction, ii) metabolic adaptation to the host, iii) antimicrobial resistance, iv) changes in virulence and the bacterial cell surface, and v) hypermutation, and comment on where the field should focus going forward.
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Affiliation(s)
- Alexandra Grote
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Ashlee M Earl
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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6
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de Korne-Elenbaas J, Bruisten SM, de Vries HJC, van Dam AP. Within-Host Genetic Variation in Neisseria gonorrhoeae over the Course of Infection. Microbiol Spectr 2022; 10:e0031322. [PMID: 35467402 PMCID: PMC9241688 DOI: 10.1128/spectrum.00313-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/02/2022] [Indexed: 11/20/2022] Open
Abstract
Knowledge of within-host genetic variation informs studies on transmission dynamics. We studied within-host genetic variation in Neisseria gonorrhoeae over the course of infection and across different anatomical locations. Isolates were obtained during a clinical trial, and isolates from consecutive time points reflected persistent infections after treatment failure. We compared sequence types (STs) and recombination unfiltered- and filtered core genome single nucleotide polymorphism (SNP) distances in 65 within-host isolate pairs from the same anatomical location over time-obtained with a median interval of 7 days-and 65 isolate pairs across different anatomical locations at one time point. Isolates with different Multi-Locus Sequence Types (MLST), NG-Sequence Types for Antimicrobial Resistance (NG-STAR) and NG-Multi Antigen Sequence Types (NG-MAST) had a median of 1466 recombination filtered SNPs, whereas a median of 1 SNP was found between isolates with identical STs or a different NG-MAST only. The threshold for differentiating between strains was set at 10 recombination filtered SNPs, showing that isolates from persistent infections could have different NG-MASTs. Antibiotic pressure applied through treatment did not lead to an increase in genetic variation in specific genes or in overall extent of variation, compared to variation across anatomical locations. Instead, within-host genetic variation was proposedly driven by the host immune response, as it was concentrated in genomic regions encoding surface exposed proteins involved in host-microbe interaction. Ultimately, 15/228 (6.5%) between-host pairs contained a single strain, suggesting between-host transmission. However, patient reported data are needed to differentiate within-host persistence from between-host transmission. IMPORTANCE Understanding transmission dynamics of Neisseria gonorrhoeae (Ng) is based on the identification of transmission events. These can be identified by assessing genetic relatedness between Ng isolates, expressed as core genome SNP distances. However, a SNP threshold to differentiate between strains needs to be defined, using knowledge on within- and between-host genetic variation. Here, we assessed within-host genetic variation, using a unique set of within-host Ng isolates from the same anatomical location over time or across different anatomical locations at one time point. The insights in genetic variation that occurred during the infection period contribute to the understanding of infection dynamics. In addition, the obtained knowledge can be used for future research on transmission dynamics and development of public health interventions based on bacterial genomic data.
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Affiliation(s)
- Jolinda de Korne-Elenbaas
- Department of Infectious Diseases, Public Health Laboratory, Public Health Service of Amsterdam, Amsterdam, the Netherlands
- Amsterdam UMC, University of Amsterdam, Department of Medical Microbiology, Amsterdam Institute for Infection and Immunity (AII), location Academic Medical Center, Amsterdam, the Netherlands
| | - Sylvia M. Bruisten
- Department of Infectious Diseases, Public Health Laboratory, Public Health Service of Amsterdam, Amsterdam, the Netherlands
- Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity (AII), Amsterdam, the Netherlands
| | - Henry J. C. de Vries
- Amsterdam UMC, University of Amsterdam, Department of Dermatology, Amsterdam Institute for Infection and Immunity (AII), location Academic Medical Center, Amsterdam, the Netherlands
- Center for Sexual Health, Department of Infectious Diseases, Public Health Service Amsterdam, Amsterdam, the Netherlands
| | - Alje P. van Dam
- Department of Infectious Diseases, Public Health Laboratory, Public Health Service of Amsterdam, Amsterdam, the Netherlands
- Amsterdam UMC, University of Amsterdam, Department of Medical Microbiology, Amsterdam Institute for Infection and Immunity (AII), location Academic Medical Center, Amsterdam, the Netherlands
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7
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Mikucki A, McCluskey NR, Kahler CM. The Host-Pathogen Interactions and Epicellular Lifestyle of Neisseria meningitidis. Front Cell Infect Microbiol 2022; 12:862935. [PMID: 35531336 PMCID: PMC9072670 DOI: 10.3389/fcimb.2022.862935] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 02/28/2022] [Indexed: 01/17/2023] Open
Abstract
Neisseria meningitidis is a gram-negative diplococcus and a transient commensal of the human nasopharynx. It shares and competes for this niche with a number of other Neisseria species including N. lactamica, N. cinerea and N. mucosa. Unlike these other members of the genus, N. meningitidis may become invasive, crossing the epithelium of the nasopharynx and entering the bloodstream, where it rapidly proliferates causing a syndrome known as Invasive Meningococcal Disease (IMD). IMD progresses rapidly to cause septic shock and meningitis and is often fatal despite aggressive antibiotic therapy. While many of the ways in which meningococci survive in the host environment have been well studied, recent insights into the interactions between N. meningitidis and the epithelial, serum, and endothelial environments have expanded our understanding of how IMD develops. This review seeks to incorporate recent work into the established model of pathogenesis. In particular, we focus on the competition that N. meningitidis faces in the nasopharynx from other Neisseria species, and how the genetic diversity of the meningococcus contributes to the wide range of inflammatory and pathogenic potentials observed among different lineages.
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Affiliation(s)
- August Mikucki
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Nicolie R. McCluskey
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
- College of Science, Health, Engineering and Education, Telethon Kids Institute, Murdoch University, Perth, WA, Australia
| | - Charlene M. Kahler
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
- *Correspondence: Charlene M. Kahler,
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8
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MacAlasdair N, Pesonen M, Brynildsrud O, Eldholm V, Kristiansen PA, Corander J, Caugant DA, Bentley SD. The effect of recombination on the evolution of a population of Neisseria meningitidis. Genome Res 2021; 31:1258-1268. [PMID: 34108268 PMCID: PMC8256868 DOI: 10.1101/gr.264465.120] [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: 04/08/2020] [Accepted: 04/22/2021] [Indexed: 12/02/2022]
Abstract
Neisseria meningitidis (the meningococcus) is a major human pathogen with a history of high invasive disease burden, particularly in sub-Saharan Africa. Our current understanding of the evolution of meningococcal genomes is limited by the rarity of large-scale genomic population studies and lack of in-depth investigation of the genomic events associated with routine pathogen transmission. Here, we fill this knowledge gap by a detailed analysis of 2839 meningococcal genomes obtained through a carriage study of over 50,000 samples collected systematically in Burkina Faso, West Africa, before, during, and after the serogroup A vaccine rollout, 2009-2012. Our findings indicate that the meningococcal genome is highly dynamic, with highly recombinant loci and frequent gene sharing across deeply separated lineages in a structured population. Furthermore, our findings illustrate how population structure can correlate with genome flexibility, as some lineages in Burkina Faso are orders of magnitude more recombinant than others. We also examine the effect of selection on the population, in particular how it is correlated with recombination. We find that recombination principally acts to prevent the accumulation of deleterious mutations, although we do also find an example of recombination acting to speed the adaptation of a gene. In general, we show the importance of recombination in the evolution of a geographically expansive population with deep population structure in a short timescale. This has important consequences for our ability to both foresee the outcomes of vaccination programs and, using surveillance data, predict when lineages of the meningococcus are likely to become a public health concern.
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Affiliation(s)
- Neil MacAlasdair
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Maiju Pesonen
- Oslo Centre for Biostatistics and Epidemiology (OCBE), Oslo University Hospital Research Support Services, Blindern, 0317 Oslo, Norway
| | - Ola Brynildsrud
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
- Department of Food Safety and Infection Biology, Faculty of Veterinary Science, Norwegian University of Life Science, 0454 Oslo, Norway
| | - Vegard Eldholm
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
| | - Paul A Kristiansen
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
| | - Jukka Corander
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
- University of Oslo, Department of Biostatistics, Blindern, 0317 Oslo, Norway
- Helsinki Institute for Information Technology HIIT, Department of Mathematics and Statistics, University of Helsinki, 00014 Helsinki, Finland
| | - Dominique A Caugant
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
- Department of Community Medicine, Faculty of Medicine, University of Oslo, Blindern, 0316 Oslo, Norway
| | - Stephen D Bentley
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
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9
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Mustapha MM, Marsh JW, Shutt KA, Schlackman J, Ezeonwuka C, Farley MM, Stephens DS, Wang X, Van Tyne D, Harrison LH. Transmission Dynamics and Microevolution of Neisseria meningitidis During Carriage and Invasive Disease in High School Students in Georgia and Maryland, 2006-2007. J Infect Dis 2020; 223:2038-2047. [PMID: 33107578 DOI: 10.1093/infdis/jiaa674] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 10/21/2020] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The mechanisms by which Neisseria meningitidis cause persistent human carriage and transition from carriage to invasive disease have not been fully elucidated. METHODS Georgia and Maryland high school students were sampled for pharyngeal carriage of N. meningitidis during the 2006-2007 school year. A total of 321 isolates from 188 carriers and all 67 invasive disease isolates collected during the same time and from the same geographic region underwent whole-genome sequencing. Core-genome multilocus sequence typing was used to compare allelic profiles, and direct read mapping was used to study strain evolution. RESULTS Among 188 N. meningitidis culture-positive students, 98 (52.1%) were N. meningitidis culture positive at 2 or 3 samplings. Most students who were positive at >1 sampling (98%) had persistence of a single strain. More than a third of students carried isolates that were highly genetically related to isolates from other students in the same school, and occasional transmission within the same county was also evident. The major pilin subunit gene, pilE, was the most variable gene, and no carrier had identical pilE sequences at different time points. CONCLUSION We found strong evidence of local meningococcal transmission at both the school and county levels. Allelic variation within genes encoding bacterial surface structures, particularly pilE, was common.
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Affiliation(s)
- Mustapha M Mustapha
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jane W Marsh
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Kathleen A Shutt
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jessica Schlackman
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Chinelo Ezeonwuka
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Monica M Farley
- Emory University Department of Medicine, Atlanta, Georgia, USA.,Atlanta VA Medical Center, Atlanta, Georgia, USA
| | | | - Xin Wang
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Daria Van Tyne
- Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Lee H Harrison
- Microbial Genomic Epidemiology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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10
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Moreno J, Alarcon Z, Parra E, Duarte C, Sanabria O, Prada D, Gabastou JM. Molecular characterization of Neisseria meningitidis isolates recovered from patients with invasive meningococcal disease in Colombia from 2013 to 2016. PLoS One 2020; 15:e0234475. [PMID: 32663215 PMCID: PMC7360035 DOI: 10.1371/journal.pone.0234475] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 05/26/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Neisseria meningitidis is a significant cause of morbidity and mortality worldwide. Meningococcal isolates have a highly dynamic population structure and can be phenotypically and genetically differentiated into serogroups and clonal complexes. The aim of this study was to describe the phenotypic and genotypic characteristics of invasive isolates recovered in Colombia from 2013 to 2016. METHODOLOGY A total of 193 invasive isolates were analyzed. Phenotypic and genotypic characteristics were determined by serotyping, antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing. RESULTS Based on the results, meningococcal serogroups C, B and Y were responsible for 47.9%, 41.7%, and 9.4% of cases, respectively, and the distribution of serogroups B and C changed over time. Fifteen clonal groups and 14 clonal complexes (cc) were identified by PFGE and genome sequencing. The main clonal group included serogroup B isolates with sequence type (ST)-9493 and its four single-locus variants, which has only been identified in Colombian isolates. The clonal population structure demonstrates that the isolates in this study mainly belong to four clonal complexes: ST-11 cc, ST-32 cc, ST-35 cc and ST-41/44 cc. Thirty-eight penA alleles were identified, but no correlation between MICs and specific sequences was observed. CONCLUSION This study shows that most meningococcal isolates recovered from patients with invasive meningococcal disease in Colombia are strains associated with distinct globally disseminated hyperinvasive clones.
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Affiliation(s)
- Jaime Moreno
- Grupo de Microbiología, Instituto Nacional de Salud (INS), Bogotá, Colombia
- * E-mail:
| | - Zonia Alarcon
- Grupo de Microbiología, Instituto Nacional de Salud (INS), Bogotá, Colombia
| | - Eliana Parra
- Grupo de Microbiología, Instituto Nacional de Salud (INS), Bogotá, Colombia
| | - Carolina Duarte
- Grupo de Microbiología, Instituto Nacional de Salud (INS), Bogotá, Colombia
| | - Olga Sanabria
- Grupo de Microbiología, Instituto Nacional de Salud (INS), Bogotá, Colombia
| | - Diego Prada
- Grupo de Microbiología, Instituto Nacional de Salud (INS), Bogotá, Colombia
| | - Jean Marc Gabastou
- Panamerican Health Organization/World Health Organization (PAHO/WHO), Washington, DC, United States of America
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11
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Brynildsrud OB, Eldholm V, Rakhimova A, Kristiansen PA, Caugant DA. Gauging the epidemic potential of a widely circulating non-invasive meningococcal strain in Africa. Microb Genom 2020; 5. [PMID: 31454306 PMCID: PMC6755499 DOI: 10.1099/mgen.0.000290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Neisseria meningitidis colonizes the human oropharynx and transmits mainly via asymptomatic carriage. Actual outbreaks of meningococcal meningitis are comparatively rare and occur when susceptible populations are exposed to hypervirulent clones, genetically distinct from the main carriage isolates. However, carriage isolates can evolve into pathogens through a limited number of recombination events. The present study examines the potential for the sequence type (ST)-192, by far the dominant clone recovered in recent meningococcal carriage studies in sub-Saharan Africa, to evolve into a pathogen. We used whole-genome sequencing on a collection of 478 meningococcal isolates sampled from 1- to 29- year-old healthy individuals in Arba Minch, southern Ethiopia in 2014. The ST-192 clone was identified in nearly 60 % of the carriers. Using complementary short- and long-read techniques for whole-genome sequencing, we were able to completely resolve genomes and thereby identify genomic differences between the ST-192 carriage strain and known pathogenic clones with the highest possible resolution. We conclude that it is possible, but unlikely, that ST-192 could evolve into a significant pathogen, thus, becoming the major invasive meningococcus clone in the meningitis belt of Africa following upcoming mass vaccination with a polyvalent conjugate vaccine that targets the A, C, W, Y and X capsules.
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Affiliation(s)
- Ola Brønstad Brynildsrud
- Department of Food Safety and Infection Biology, Faculty of Veterinary Science, Norwegian University of Life Science, Oslo, Norway.,Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Vegard Eldholm
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Adelina Rakhimova
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | | | - Dominique A Caugant
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway.,WHO Collaborating Centre for Reference and Research on Meningococci, Norwegian Institute of Public Health, Oslo, Norway.,Department of Community Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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12
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Joseph SJ, Topaz N, Chang HY, Whaley MJ, Vuong JT, Chen A, Hu F, Schmink SE, Jenkins LT, Rodriguez-Rivera LD, Thomas JD, Acosta AM, McNamara L, Soeters HM, Mbaeyi S, Wang X. Insights on Population Structure and Within-Host Genetic Changes among Meningococcal Carriage Isolates from U.S. Universities. mSphere 2020; 5:e00197-20. [PMID: 32269159 PMCID: PMC7142301 DOI: 10.1128/msphere.00197-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 03/17/2020] [Indexed: 01/15/2023] Open
Abstract
In 2015 and 2016, meningococcal carriage evaluations were conducted at two universities in the United States following mass vaccination campaigns in response to Neisseria meningitidis serogroup B (NmB) disease outbreaks. A simultaneous carriage evaluation was also conducted at a university near one of the outbreaks, where no NmB cases were reported and no mass vaccination occurred. A total of ten cross-sectional carriage evaluation rounds were conducted, resulting in 1,514 meningococcal carriage isolates collected from 7,001 unique participants; 1,587 individuals were swabbed at multiple time points (repeat participants). All isolates underwent whole-genome sequencing. The most frequently observed clonal complexes (CC) were CC198 (27.3%), followed by CC1157 (17.4%), CC41/44 (9.8%), CC35 (7.4%), and CC32 (5.6%). Phylogenetic analysis identified carriage isolates that were highly similar to the NmB outbreak strains; comparative genomics between these outbreak and carriage isolates revealed genetic changes in virulence genes. Among repeat participants, 348 individuals carried meningococcal bacteria during at least one carriage evaluation round; 50.3% retained N. meningitidis carriage of a strain with the same sequence type (ST) and CC across rounds, 44.3% only carried N. meningitidis in one round, and 5.4% acquired a new N. meningitidis strain between rounds. Recombination, point mutations, deletions, and simple sequence repeats were the most frequent genetic mechanisms found in isolates collected from hosts carrying a strain of the same ST and CC across rounds. Our findings provide insight on the dynamics of meningococcal carriage among a population that is at higher risk for invasive meningococcal disease than the general population.IMPORTANCE U.S. university students are at a higher risk of invasive meningococcal disease than the general population. The responsible pathogen, Neisseria meningitidis, can be carried asymptomatically in the oropharynx; the dynamics of meningococcal carriage and the genetic features that distinguish carriage versus disease states are not completely understood. Through our analyses, we aimed to provide data to address these topics. We whole-genome sequenced 1,514 meningococcal carriage isolates from individuals at three U.S. universities, two of which underwent mass vaccination campaigns following recent meningococcal outbreaks. We describe the within-host genetic changes among individuals carrying a strain with the same molecular type over time, the primary strains being carried in this population, and the genetic differences between closely related outbreak and carriage strains. Our results provide detailed information on the dynamics of meningococcal carriage and the genetic differences in carriage and outbreak strains, which can inform future efforts to reduce the incidence of invasive meningococcal disease.
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Affiliation(s)
| | | | | | - Melissa J Whaley
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jeni T Vuong
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Alexander Chen
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Fang Hu
- IHRC Inc., Atlanta, Georgia, USA
| | - Susanna E Schmink
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Laurel T Jenkins
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - Jennifer D Thomas
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Anna M Acosta
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Lucy McNamara
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Heidi M Soeters
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Sarah Mbaeyi
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Xin Wang
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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13
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Alfsnes K, Eldholm V, Olsen AO, Brynildsrud OB, Bohlin J, Steinbakk M, Caugant DA. Genomic epidemiology and population structure of Neisseria gonorrhoeae in Norway, 2016-2017. Microb Genom 2020; 6:e000359. [PMID: 32213251 PMCID: PMC7276708 DOI: 10.1099/mgen.0.000359] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 03/09/2020] [Indexed: 12/17/2022] Open
Abstract
This study presents the nationwide epidemiology of Neisseria gonorrhoeae, using whole-genome sequencing of all culture-positive cases, which comprise roughly 40 % of all cases of gonorrhea reported in Norway from 2016 to 2017. Isolates were assigned to sequence types and Bayesian analysis clusters and variation in genes coding for antibiotic resistance was linked to phenotypic resistance data. The study also included isolates taken from the same patients from different anatomical sites at one or more time points. Comparing these isolates allows for observation of patterns of infections, i.e. multiple reinfections of genetically related clones vs. reinfections of genetically distant clones, and quantification of the genomic variation of closely related isolates from samples taken from a patient within the same day. Demographically, the patients in the study could be split into two groups; one group of patients from the capital with a high proportion of men who have sex with men (MSM), and another consisting of young adults with transmission primarily between males and females from outside the capital. Some clusters of N. gonorrhoeae were restricted to one of these two demographic groups. Pairwise comparison of multiple isolates from the same patients revealed that most were reinfected with different clones. Observations of frequent reinfections in patients is a concern and should be taken into account in the development of improved information and treatment guidelines.
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Affiliation(s)
- Kristian Alfsnes
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Vegard Eldholm
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Anne Olaug Olsen
- National Advisory Unit for Sexually Transmitted Infections, Oslo, Norway
- Institute for Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Ola Brønstad Brynildsrud
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Jon Bohlin
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Martin Steinbakk
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
- Østfold Hospital Trust, Center for Laboratory Medicine, Grålum, Norway
| | - Dominique A. Caugant
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
- Institute for Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway
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14
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Watle SV, Caugant DA, Tunheim G, Bekkevold T, Laake I, Brynildsrud OB, Næss LM. Meningococcal carriage in Norwegian teenagers: strain characterisation and assessment of risk factors. Epidemiol Infect 2020; 148:e80. [PMID: 32228726 PMCID: PMC7189347 DOI: 10.1017/s0950268820000734] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/06/2020] [Accepted: 03/19/2020] [Indexed: 11/24/2022] Open
Abstract
Teenagers have a higher risk of invasive meningococcal disease (IMD) than the general population. This cross-sectional study aimed to characterise strains of Neisseria meningitidis circulating among Norwegian teenagers and to assess risk factors for meningococcal carriage. Oropharyngeal swabs were collected from secondary-school students in southeastern Norway in 2018-2019. Meningococcal isolates were characterised using whole genome sequencing. Risk factors for meningococcal carriage were assessed from questionnaire data. Samples were obtained from 2296 12-24-year-olds (majority 13-19-year-olds). N. meningitidis was identified in 167 (7.3%) individuals. The highest carriage rate was found among 18-year-olds (16.4%). Most carriage isolates were capsule null (40.1%) or genogroup Y (33.5%). Clonal complexes cc23 (35.9%) and cc198 (32.3%) dominated and 38.9% of carriage strains were similar to invasive strains currently causing IMD in Norway. Use of Swedish snus (smokeless tobacco) (OR 1.56, 95% CI 1.07-2.27), kissing >two persons/month (OR 2.76, 95% CI 1.49-5.10) and partying >10 times/3months (OR 3.50, 95% CI 1.45-8.48) were associated with carriage, while age, cigarette smoking, sharing of drinking bottles and meningococcal vaccination were not. The high meningococcal carriage rate among 18-year-olds is probably due to risk-related behaviour. Use of Swedish snus is possibly a new risk factor for meningococcal carriage. Almost 40% of circulating carriage strains have invasive potential.
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Affiliation(s)
- S. V. Watle
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 222 Skøyen, 0213 Oslo, Norway
- Faculty of Medicine, Institute of Health and Society, University of Oslo, P.O. Box 1078 Blindern, 0316 Oslo, Norway
| | - D. A. Caugant
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 222 Skøyen, 0213 Oslo, Norway
- Faculty of Medicine, Institute of Health and Society, University of Oslo, P.O. Box 1078 Blindern, 0316 Oslo, Norway
| | - G. Tunheim
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 222 Skøyen, 0213 Oslo, Norway
| | - T. Bekkevold
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 222 Skøyen, 0213 Oslo, Norway
| | - I. Laake
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 222 Skøyen, 0213 Oslo, Norway
| | - O. B. Brynildsrud
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 222 Skøyen, 0213 Oslo, Norway
| | - L. M. Næss
- Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, P.O. Box 222 Skøyen, 0213 Oslo, Norway
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15
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Saltykova A, Mattheus W, Bertrand S, Roosens NHC, Marchal K, De Keersmaecker SCJ. Detailed Evaluation of Data Analysis Tools for Subtyping of Bacterial Isolates Based on Whole Genome Sequencing: Neisseria meningitidis as a Proof of Concept. Front Microbiol 2019; 10:2897. [PMID: 31921072 PMCID: PMC6930190 DOI: 10.3389/fmicb.2019.02897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 12/02/2019] [Indexed: 12/19/2022] Open
Abstract
Whole genome sequencing is increasingly recognized as the most informative approach for characterization of bacterial isolates. Success of the routine use of this technology in public health laboratories depends on the availability of well-characterized and verified data analysis methods. However, multiple subtyping workflows are now often being used for a single organism, and differences between them are not always well described. Moreover, methodologies for comparison of subtyping workflows, and assessment of their performance are only beginning to emerge. Current work focuses on the detailed comparison of WGS-based subtyping workflows and evaluation of their suitability for the organism and the research context in question. We evaluated the performance of pipelines used for subtyping of Neisseria meningitidis, including the currently widely applied cgMLST approach and different SNP-based methods. In addition, the impact of the use of different tools for detection and filtering of recombinant regions and of different reference genomes were tested. Our benchmarking analysis included both assessment of technical performance of the pipelines and functional comparison of the generated genetic distance matrices and phylogenetic trees. It was carried out using replicate sequencing datasets of high- and low-coverage, consisting mainly of isolates belonging to the clonal complex 269. We demonstrated that cgMLST and some of the SNP-based subtyping workflows showed very good performance characteristics and highly similar genetic distance matrices and phylogenetic trees with isolates belonging to the same clonal complex. However, only two of the tested workflows demonstrated reproducible results for a group of more closely related isolates. Additionally, results of the SNP-based subtyping workflows were to some level dependent on the reference genome used. Interestingly, the use of recombination-filtering software generally reduced the similarity between the gene-by-gene and SNP-based methodologies for subtyping of N. meningitidis. Our study, where N. meningitidis was taken as an example, clearly highlights the need for more benchmarking comparative studies to eventually contribute to a justified use of a specific WGS data analysis workflow within an international public health laboratory context.
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Affiliation(s)
- Assia Saltykova
- Transversal Activities in Applied Genomics, Sciensano, Brussels, Belgium
- IDLab, IMEC, Department of Information Technology, Ghent University, Ghent, Belgium
| | - Wesley Mattheus
- Belgian National Reference Centre for Neisseria, Human Bacterial Diseases, Sciensano, Brussels, Belgium
| | - Sophie Bertrand
- Belgian National Reference Centre for Neisseria, Human Bacterial Diseases, Sciensano, Brussels, Belgium
| | | | - Kathleen Marchal
- IDLab, IMEC, Department of Information Technology, Ghent University, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, VIB, Ghent University, Ghent, Belgium
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16
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Caugant DA, Brynildsrud OB. Neisseria meningitidis: using genomics to understand diversity, evolution and pathogenesis. Nat Rev Microbiol 2019; 18:84-96. [PMID: 31705134 DOI: 10.1038/s41579-019-0282-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2019] [Indexed: 01/30/2023]
Abstract
Meningococcal disease remains an important cause of morbidity and death worldwide despite the development and increasing implementation of effective vaccines. Elimination of the disease is hampered by the enormous diversity and antigenic variability of the causative agent, Neisseria meningitidis, one of the most variable bacteria in nature. These features are attained mainly through high rates of horizontal gene transfer and alteration of protein expression through phase variation. The recent availability of whole-genome sequencing (WGS) of large-scale collections of N. meningitidis isolates from various origins, databases to facilitate storage and sharing of WGS data and the concomitant development of effective bioinformatics tools have led to a much more thorough understanding of the diversity of the species, its evolution and population structure and how virulent traits may emerge. Implementation of WGS is already contributing to enhanced epidemiological surveillance and is essential to ascertain the impact of vaccination strategies. This Review summarizes the recent advances provided by WGS studies in our understanding of the biology of N. meningitidis and the epidemiology of meningococcal disease.
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Affiliation(s)
- Dominique A Caugant
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway. .,Department of Community Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Ola B Brynildsrud
- Division for Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway.,Department of Food Safety and Infection Biology, Faculty of Veterinary Science, Norwegian University of Life Science, Oslo, Norway
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17
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Abstract
Neisseria meningitidis (the meningococcus) is a member of the normal nasopharyngeal microbiome in healthy individuals, but can cause septicemia and meningitis in susceptible individuals. In this chapter we provide an overview of the disease caused by N. meningitidis and the schemes used to type the meningococcus. We also review the adhesions, virulence factors, and phase variable genes that enable it to successfully colonize the human host. Finally, we outline the history and current status of meningococcal vaccines and highlight the importance of continued molecular investigation of the epidemiology and the structural analysis of the antigens of this pathogen to aid future vaccine development.
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18
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Greenwood BM, Aseffa A, Caugant DA, Diallo K, Kristiansen PA, Maiden MCJ, Stuart JM, Trotter CL. Narrative review of methods and findings of recent studies on the carriage of meningococci and other Neisseria species in the African Meningitis Belt. Trop Med Int Health 2018; 24:143-154. [PMID: 30461138 PMCID: PMC7380001 DOI: 10.1111/tmi.13185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Objective To review the findings of studies of pharyngeal carriage of Neisseria meningitidis and related species conducted in the African meningitis belt since a previous review published in 2007. Methods PubMed and Web of Science were searched in July 2018 using the terms ‘meningococcal OR Neisseria meningitidis OR lactamica AND carriage AND Africa’, with the search limited to papers published on or after 1st January 2007. We conducted a narrative review of these publications. Results One hundred and thirteen papers were identified using the search terms described above, 20 of which reported new data from surveys conducted in an African meningitis belt country. These papers described 40 surveys conducted before the introduction of the group A meningococcal conjugate vaccine (MenAfriVacR) during which 66 707 pharyngeal swabs were obtained. Carriage prevalence of N. meningitidis varied substantially by time and place, ranging from <1% to 24%. The mean pharyngeal carriage prevalence of N. meningitidis across all surveys was 4.5% [95% CI: 3.4%, 6.8%] and that of capsulated N. meningitidis was 2.8% [95% CI: 1.9%; 5.2%]. A study of households provided strong evidence for meningococcal transmission within and outside households. The introduction of MenAfriVac® led to marked reductions in carriage of the serogroup A meningococcus in Burkina Faso and Chad. Conclusions Recent studies employing standardised methods confirm the findings of older studies that carriage of N. meningitidis in the African meningitis belt is highly variable over time and place, but generally occurs with a lower prevalence and shorter duration than reported from industrialised countries.
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Affiliation(s)
| | - Abraham Aseffa
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | | | - Kanny Diallo
- Department of Bacteriology, Noguchi Memorial Research Institute, University of Legon, Accra, Legon
| | | | | | - James M Stuart
- London School of Hygiene & Tropical Medicine, London, UK
| | - Caroline L Trotter
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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19
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Phase-Variable Genotypes Sweetened by Glycosylation Phenotypes. J Bacteriol 2018; 200:JB.00316-18. [PMID: 29866804 DOI: 10.1128/jb.00316-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The affordability of bacterial genome sequencing has provided a helpful tool for sequencing large strain collections. Bente Børud (J. Bacteriol. 200:e00794-17, 2018, https://doi.org/doi:10.1128/JB.00794-17) recently led an effort to analyze the genomes of a collection of oropharyngeal Neisseria meningitidis isolates from 50 healthy individuals. Paired longitudinal isolates from each individual were sequenced. Genome analyses focused on (i) predicting the expression state of phase-variable loci that encode enzymes important for O-linked protein glycosylation and (ii) correlating specific genotypes with glycosylation phenotypes.
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20
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Genotypic and Phenotypic Characterization of the O-Linked Protein Glycosylation System Reveals High Glycan Diversity in Paired Meningococcal Carriage Isolates. J Bacteriol 2018; 200:JB.00794-17. [PMID: 29555702 DOI: 10.1128/jb.00794-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 03/14/2018] [Indexed: 01/15/2023] Open
Abstract
Species within the genus Neisseria display significant glycan diversity associated with the O-linked protein glycosylation (pgl) systems due to phase variation and polymorphic genes and gene content. The aim of this study was to examine in detail the pgl genotype and glycosylation phenotype in meningococcal isolates and the changes occurring during short-term asymptomatic carriage. Paired meningococcal isolates derived from 50 asymptomatic meningococcal carriers, taken about 2 months apart, were analyzed with whole-genome sequencing. The O-linked protein glycosylation genes were characterized in detail using the Genome Comparator tool at the https://pubmlst.org/ database. Immunoblotting with glycan-specific antibodies (Abs) was used to investigate the protein glycosylation phenotype. All major pgl locus polymorphisms identified in Neisseria meningitidis to date were present in our isolate collection, with the variable presence of pglG and pglH, both in combination with either pglB or pglB2 We identified significant changes and diversity in the pgl genotype and/or glycan phenotype in 96% of the paired isolates. There was also a high degree of glycan microheterogeneity, in which different variants of glycan structures were found at a given glycoprotein. The main mechanism responsible for the observed differences was phase-variable expression of the involved glycosyltransferases and the O-acetyltransferase. To our knowledge, this is the first characterization of the pgl genotype and glycosylation phenotype in a larger strain collection. This report thus provides important insight into glycan diversity in N. meningitidis and into the phase variability changes that influence the expressed glycoform repertoire during meningococcal carriage.IMPORTANCE Bacterial meningitis is a serious global health problem, and one of the major causative organisms is Neisseria meningitidis, which is also a common commensal in the upper respiratory tract of healthy humans. In bacteria, numerous loci involved in biosynthesis of surface-exposed antigenic structures that are involved in the interaction between bacteria and host are frequently subjected to homologous recombination and phase variation. These mechanisms are well described in Neisseria, and phase variation provides the ability to change these structures reversibly in response to the environment. Protein glycosylation systems are becoming widely identified in bacteria, and yet little is known about the mechanisms and evolutionary forces influencing glycan composition during carriage and disease.
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21
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Acquisition of virulence genes by a carrier strain gave rise to the ongoing epidemics of meningococcal disease in West Africa. Proc Natl Acad Sci U S A 2018; 115:5510-5515. [PMID: 29735685 PMCID: PMC6003489 DOI: 10.1073/pnas.1802298115] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Historically, Neisseria meningitidis serogroup A strains have caused large epidemics of meningitis across sub-Saharan Africa. Following mass vaccination from 2010, serogroup A outbreaks have been mostly eliminated. Starting in 2013 however, yearly epidemics of a previously unknown serogroup C strain have led to tens of thousands of cases in Nigeria and Niger. We show how this new strain evolved from a benign ancestor through the acquisition of virulence genes encoding the serogroup C capsule and a phage linked to invasiveness, illustrating that minor genetic changes in a microbe can have major public health consequences. Our reconstruction of the spatiotemporal outbreak dynamics in the Niger–Nigeria border region suggests direct epidemiological consequences of contrasting outbreak responses in the two countries. In the African meningitis belt, a region of sub-Saharan Africa comprising 22 countries from Senegal in the west to Ethiopia in the east, large epidemics of serogroup A meningococcal meningitis have occurred periodically. After gradual introduction from 2010 of mass vaccination with a monovalent meningococcal A conjugate vaccine, serogroup A epidemics have been eliminated. Starting in 2013, the northwestern part of Nigeria has been affected by yearly outbreaks of meningitis caused by a novel strain of serogroup C Neisseria meningitidis (NmC). In 2015, the strain spread to the neighboring country Niger, where it caused a severe epidemic. Following a relative calm in 2016, the largest ever recorded epidemic of NmC broke out in Nigeria in 2017. Here, we describe the recent evolution of this new outbreak strain and show how the acquisition of capsule genes and virulence factors by a strain previously circulating asymptomatically in the African population led to the emergence of a virulent pathogen. This study illustrates the power of long-read whole-genome sequencing, combined with Illumina sequencing, for high-resolution epidemiological investigations.
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22
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Siena E, Bodini M, Medini D. Interplay Between Virulence and Variability Factors as a Potential Driver of Invasive Meningococcal Disease. Comput Struct Biotechnol J 2018; 16:61-69. [PMID: 29686800 PMCID: PMC5910500 DOI: 10.1016/j.csbj.2018.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 01/29/2018] [Accepted: 02/11/2018] [Indexed: 01/09/2023] Open
Abstract
Neisseria meningitidis (Nm) is frequently found in the upper respiratory tract of the human population. Despite its prevalence as a commensal organism, Nm can occasionally invade the pharyngeal mucosal epithelium causing septicemia and life-threatening disease. A number of studies have tried to identify factors that are responsible for the onset of a virulent phenotype. Despite this however, we still miss clear causative elements. Several factors have been identified to be associated to an increased susceptibility to meningococcal disease in humans. None of them, however, could unambiguously discriminate healthy carrier from infected individuals. Similarly, comparative studies of virulent and apathogenic strains failed to identify virulence factors that could explain the emergence of the pathogenic phenotype. In line with this, a recent study of within host evolution found that Nm accumulates genomic changes during the asymptomatic carriage phase and that these are likely to contribute to the shift to a pathogenic phenotype. These results suggest that the presence of virulence factors in the meningococcal genome is not a sufficient condition for developing virulent traits, but is rather the ability to promote phenotypic variation, through the stochastic assortment of the repertoire of such factors, which could explain the occasional and unpredictable onset of IMD. Here, we present a series of argumentations supporting the hypothesis that invasive meningococcal disease comes as a result of the coexistence of bacterial virulence and variability factors in a plot that can be further complicated by additional latent factors, like host pre-existing immune status and genetic predisposition.
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23
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Kimura B. Will the emergence of core genome MLST end the role of in silico MLST? Food Microbiol 2017; 75:28-36. [PMID: 30056960 DOI: 10.1016/j.fm.2017.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 09/02/2017] [Accepted: 09/08/2017] [Indexed: 11/19/2022]
Abstract
The technological advancement of molecular epidemiological analysis using next-generation sequencing (NGS) for foodborne pathogens has a groundbreaking impact over the past three years. In particular, the emergence of cg (core genome) multilocus sequence typing(MLST) has a significant impact. This is because this technology made it possible for many researchers to carry out molecular epidemiological analysis on foodborne pathogens in a common language, using common definitions. The resolution of core genome MLST (cgMLST) far surpasses that of MLST, which only uses seven (usually, in some cases five) housekeeping genes. Therefore, cgMLST would in no doubt terminate the role of conventional MLST as the molecular epidemiological tool. However, the role of MLST would probably not end all together. Rather, the sequence type (ST) of the conventional MLST is expected to be used as in silico MLST by a wider range of researchers than ever in the next 10 years. This is because, with the arrival of the NGS era, we have come to be able to obtain ST of conventional MLST by simply entering the NGS text file into one's own PC. In other words, acquisition of ST data is no longer limited to researchers aiming to conduct MLST for the first place. The impact of such a change is large. In silico MLST will continue to be used as a tool for understanding the broad characteristics of bacterial strains. This review aimed to summarize the main information on STs that have been accumulated for representative foodborne pathogens, in particular for potential NGS users in this new era who have been not familiar with MLST until now.
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Affiliation(s)
- Bon Kimura
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology (TUMSAT), Konan 4-5-7, Minato-ku, Tokyo 108-8477, Japan.
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