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Dekaj E, Gjini E. Pneumococcus and the stress-gradient hypothesis: A trade-off links R 0 and susceptibility to co-colonization across countries. Theor Popul Biol 2024; 156:77-92. [PMID: 38331222 DOI: 10.1016/j.tpb.2024.02.001] [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: 05/30/2022] [Revised: 10/06/2023] [Accepted: 02/01/2024] [Indexed: 02/10/2024]
Abstract
Modern molecular technologies have revolutionized our understanding of bacterial epidemiology, but reported data across studies and different geographic endemic settings remain under-integrated in common theoretical frameworks. Pneumococcus serotype co-colonization, caused by the polymorphic bacteria Streptococcus pneumoniae, has been increasingly investigated and reported in recent years. While the global genomic diversity and serotype distribution of S. pneumoniae have been well-characterized, there is limited information on how co-colonization patterns vary globally, critical for understanding the evolution and transmission dynamics of the bacteria. Gathering a rich dataset of cross-sectional pneumococcal colonization studies in the literature, we quantified patterns of transmission intensity and co-colonization prevalence variation in children populations across 17 geographic locations. Linking these data to an SIS model with cocolonization under the assumption of quasi-neutrality among multiple interacting strains, our analysis reveals strong patterns of negative co-variation between transmission intensity (R0) and susceptibility to co-colonization (k). In line with expectations from the stress-gradient-hypothesis in ecology (SGH), pneumococcus serotypes appear to compete more in co-colonization in high-transmission settings and compete less in low-transmission settings, a trade-off which ultimately leads to a conserved ratio of single to co-colonization μ=1/(R0-1)k. From the mathematical model's behavior, such conservation suggests preservation of 'stability-diversity-complexity' regimes in coexistence of similar co-colonizing strains. We find no major differences in serotype compositions across studies, pointing to adaptation of the same set of serotypes across variable environments as an explanation for their differential interaction in different transmission settings. Our work highlights that the understanding of transmission patterns of Streptococcus pneumoniae from global scale epidemiological data can benefit from simple analytical approaches that account for quasi-neutrality among strains, co-colonization, as well as variable environmental adaptation.
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Affiliation(s)
- Ermanda Dekaj
- Center for Computational and Stochastic Mathematics, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Erida Gjini
- Center for Computational and Stochastic Mathematics, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal.
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2
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Apte A, Dayma G, Naziat H, Williams L, Sanghavi S, Uddin J, Kawade A, Islam M, Kar S, Li Y, Kyaw MH, Juvekar S, Campbell H, Nair H, Saha SK, Bavdekar A. Nasopharyngeal pneumococcal carriage in South Asian infants: Results of observational cohort studies in vaccinated and unvaccinated populations. J Glob Health 2021; 11:04054. [PMID: 34552723 PMCID: PMC8442578 DOI: 10.7189/jogh.11.04054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background Nasopharyngeal pneumococcal carriage (NPC) is a prerequisite for invasive pneumococcal disease and reduced carriage of vaccine serotypes is a marker for the protection offered by the pneumococcal conjugate vaccine (PCV). The present study reports NPC during the first year of life in a vaccinated (with PCV10) cohort in Bangladesh and an unvaccinated cohort in India. Methods A total of 450 and 459 infants were recruited from India and Bangladesh respectively within 0-7 days after birth. Nasopharyngeal swabs were collected at baseline, 18 and 36 weeks after birth. The swabs were processed for pneumococcal culture and identification of serotypes by the Quellung test and polymerase chain reaction (PCR). An identical protocol was applied at both sites. Results Prevalence of NPC was 48% in the Indian and 54.8% in the Bangladeshi cohort at 18 weeks. It increased to 53% and 64.8% respectively at 36 weeks. The average prevalence of vaccine serotypes was higher in the Indian cohort (17.8% vs 9.8% for PCV-10 and 26.1% vs17.6% for PCV-13) with 6A, 6B, 19F, 23F, and 19A as the common serotypes. On the other hand, the prevalence of non-vaccine serotypes was higher (43.6% vs 27.1% for non-PCV13) in the Bangladeshi cohort with 34, 15B, 17F, and 35B as the common serotypes. Overcrowding was associated with increased risk of pneumococcal carriage. The present PCV-13 vaccine would cover 28%-30% and 47%-48% serotypes in the Bangladeshi and Indian cohorts respectively. Conclusions South Asian infants get colonised with pneumococci early in infancy; predominantly vaccine serotypes in PCV naïve population (India) and non-vaccine serotypes in the vaccinated population (Bangladesh). These local findings are important to inform the public health policy and the development of higher valent pneumococcal vaccines.
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Affiliation(s)
- Aditi Apte
- KEM Hospital Research Centre, Pune, Maharashtra, India
| | - Girish Dayma
- KEM Hospital Research Centre, Pune, Maharashtra, India
| | - Hakka Naziat
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - Linda Williams
- Centre for Global Health, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK
| | | | - Jamal Uddin
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - Anand Kawade
- KEM Hospital Research Centre, Pune, Maharashtra, India
| | - Maksuda Islam
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - Sanchita Kar
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh
| | - You Li
- Centre for Global Health, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK
| | - Moe H Kyaw
- Sanofi Pasteur, Swiftwater, Pensylvania, USA
| | - Sanjay Juvekar
- KEM Hospital Research Centre, Pune, Maharashtra, India.,Savitribai Phule University, Pune, Maharashtra, India
| | - Harry Campbell
- Centre for Global Health, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK
| | - Harish Nair
- Centre for Global Health, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK
| | - Samir K Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu Hospital, Dhaka, Bangladesh
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3
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Knight JR, Dunne EM, Mulholland EK, Saha S, Satzke C, Tothpal A, Weinberger DM. Determining the serotype composition of mixed samples of pneumococcus using whole-genome sequencing. Microb Genom 2021; 7:mgen000494. [PMID: 33355528 PMCID: PMC8115901 DOI: 10.1099/mgen.0.000494] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 11/27/2020] [Indexed: 11/18/2022] Open
Abstract
Serotyping of Streptococcus pneumoniae is a critical tool in the surveillance of the pathogen and in the development and evaluation of vaccines. Whole-genome DNA sequencing and analysis is becoming increasingly common and is an effective method for pneumococcal serotype identification of pure isolates. However, because of the complexities of the pneumococcal capsular loci, current analysis software requires samples to be pure (or nearly pure) and only contain a single pneumococcal serotype. We introduce a new software tool called SeroCall, which can identify and quantitate the serotypes present in samples, even when several serotypes are present. The sample preparation, library preparation and sequencing follow standard laboratory protocols. The software runs as fast as or faster than existing identification tools on typical computing servers and is freely available under an open source licence at https://github.com/knightjimr/serocall. Using samples with known concentrations of different serotypes as well as blinded samples, we were able to accurately quantify the abundance of different serotypes of pneumococcus in mixed cultures, with 100 % accuracy for detecting the major serotype and up to 86 % accuracy for detecting minor serotypes. We were also able to track changes in serotype frequency over time in an experimental setting. This approach could be applied in both epidemiological field studies of pneumococcal colonization and experimental laboratory studies, and could provide a cheaper and more efficient method for serotyping than alternative approaches.
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Affiliation(s)
- James R. Knight
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, USA
| | - Eileen M. Dunne
- Infection and Immunity, Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - E. Kim Mulholland
- Infection and Immunity, Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Sudipta Saha
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
| | - Catherine Satzke
- Infection and Immunity, Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, Victoria, Australia
| | - Adrienn Tothpal
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
- Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary
| | - Daniel M. Weinberger
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, USA
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4
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Abstract
Gram-positive bacteria employ an array of secreted peptides to control population-level behaviors in response to environmental cues. We review mechanistic and functional features of secreted peptides produced by the human pathogen Streptococcus pneumoniae. We discuss sequence features, mechanisms of transport, and receptors for 3 major categories of small peptides: the double-glycine peptides, the Rap, Rgg, NprR, PlcR, and PrgX (RRNPP)-binding peptides, and the lanthionine-containing peptides. We highlight the impact of factors that contribute to carriage and pathogenesis, specifically genetic diversity, microbial competition, biofilm development, and environmental adaptation. A recent expansion in pneumococcal peptide studies reveals a complex network of interacting signaling systems where multiple peptides are integrated into the same signaling pathway, allowing multiple points of entry into the pathway and extending information content in new directions. In addition, since peptides are present in the extracellular milieu, there are opportunities for crosstalk, quorum sensing (QS), as well as intra- and interstrain and species interactions. Knowledge on the manner that population-level behaviors contribute to disease provides an avenue for the design and development of anti-infective strategies.
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5
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Motib AS, Al-Bayati FAY, Manzoor I, Shafeeq S, Kadam A, Kuipers OP, Hiller NL, Andrew PW, Yesilkaya H. TprA/PhrA Quorum Sensing System Has a Major Effect on Pneumococcal Survival in Respiratory Tract and Blood, and Its Activity Is Controlled by CcpA and GlnR. Front Cell Infect Microbiol 2019; 9:326. [PMID: 31572692 PMCID: PMC6753895 DOI: 10.3389/fcimb.2019.00326] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/29/2019] [Indexed: 12/25/2022] Open
Abstract
Streptococcus pneumoniae is able to cause deadly diseases by infecting different tissues, each with distinct environmental and nutritional compositions. We hypothesize that the adaptive capabilities of the microbe is an important facet of pneumococcal survival in fluctuating host environments. Quorum-sensing (QS) mechanisms are pivotal for microbial host adaptation. We previously demonstrated that the TprA/PhrA QS system is required for pneumococcal utilization of galactose and mannose, neuraminidase activity, and virulence. We also showed that the system can be modulated by using linear molecularly imprinted polymers. Due to being a drugable target, we further studied the operation of this QS system in S. pneumoniae. We found that TprA controls the expression of nine different operons on galactose and mannose. Our data revealed that TprA expression is modulated by a complex regulatory network, where the master regulators CcpA and GlnR are involved in a sugar dependent manner. Mutants in the TprA/PhrA system are highly attenuated in their survival in nasopharynx and lungs after intranasal infection, and growth in blood after intravenous infection.
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Affiliation(s)
- Anfal Shakir Motib
- Department of Infection, Immunity & Inflammation, University of Leicester, Leicester, United Kingdom.,Department of Microbiology, College of Medicine, University of Diyala, Baqubah, Iraq
| | - Firas A Y Al-Bayati
- Department of Infection, Immunity & Inflammation, University of Leicester, Leicester, United Kingdom.,College of Pharmacy, University of Kirkuk, Kirkuk, Iraq
| | - Irfan Manzoor
- Molecular Genetics, University of Groningen, Groningen, Netherlands
| | - Sulman Shafeeq
- Molecular Genetics, University of Groningen, Groningen, Netherlands
| | - Anagha Kadam
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Oscar P Kuipers
- Molecular Genetics, University of Groningen, Groningen, Netherlands
| | - N Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Peter W Andrew
- Department of Infection, Immunity & Inflammation, University of Leicester, Leicester, United Kingdom
| | - Hasan Yesilkaya
- Department of Infection, Immunity & Inflammation, University of Leicester, Leicester, United Kingdom
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Abstract
INTRODUCTION Children with nephrotic syndrome are susceptible to invasive bacterial infections. In this study, we aimed to: (1) determine the pathogens associated with infections in children with nephrotic syndrome and (2) describe antimicrobial susceptibility and serotype distribution of Streptococcus pneumoniae to guide evidence-based treatment and prevention policies. METHODS From June 2013 to March 2015, we collected blood and/or ascitic fluid from children hospitalized with nephrotic syndrome and suspected bacterial disease in the largest pediatric hospital of Bangladesh. We cultured all samples and performed polymerase chain reaction (PCR) and immunochromatographic test on ascitic fluid for detection of S. pneumoniae. Pneumococcal isolates were tested for antibiotic susceptibility using disc diffusion and serotyped using Quellung reaction and PCR. RESULTS We identified 1342 children hospitalized with nephrotic syndrome. Among them, 608 children had suspected bacterial disease from whom blood and/or ascitic fluid were collected. A pathogen was identified in 8% (48/608) of cases, 94% (45/48) of which were S. pneumoniae. Most (73%, 33/45) pneumococcal infections were identified through culture of blood and ascitic fluid and 27% (12/45) through immunochromatographic test and PCR of ascitic fluid. In total, 24 different pneumococcal serotypes were detected; 51% are covered by PCV10 (+6A), 53% by PCV13 and 60% by PPSV23. All pneumococcal isolates were susceptible to penicillin. CONCLUSIONS Because S. pneumoniae was the primary cause of invasive infections, pneumococcal vaccines may be considered as a preventive intervention in children with nephrotic syndrome. Additionally, penicillin can be used to prevent and treat pneumococcal infections in children with nephrotic syndrome in Bangladesh.
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Schembri J, Gillis HD, Lang ALS, Warhuus M, Martin I, Demczuk W, ElSherif M, McNeil SA, LeBlanc JJ. Multi-target plasmid controls for conventional and real-time PCR-based serotyping of Streptococcus pneumoniae. Plasmid 2018; 98:45-51. [PMID: 30217467 DOI: 10.1016/j.plasmid.2018.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 09/10/2018] [Accepted: 09/10/2018] [Indexed: 11/28/2022]
Abstract
BACKGROUND Serotyping of Streptococcus pneumoniae is an integral part of disease surveillance, with over 92 serotypes characterized to date using traditional serotyping. To identify the most predominant disease causing serotypes, molecular serotyping methods are now increasingly being used, like conventional and real-time multiplex PCR (cmPCR and rmPCR, respectively). Given that cmPCR consists of eight reactions spanning 41 targets, and rmPCR consists of seven triplex reactions, standardizing positive controls for these assays is challenging. As such, a 43-target plasmid for cmPCR (pSpn-CM1) and a 23 target plasmid for rmPCR (pSpn-RM1) were designed and validated. METHODS Plasmid pSpn-RM1 was designed and synthesized as chimeric DNA sequences to include all PCR target primer binding sites sequences for cmPCR. Plasmid pSpn-RM1 consisted of all primer and probe sequences required for rmPCR. Additional targets (lytA and cpsA) were included in both plasmids for quantification, following their propagation and purification from Escherichia coli. RESULTS When tested using the cmPCR reactions, all targets could be reproducibly be detected using pSpn-CM1 as template, with good amplicon visibility at a concentration of 1.4 (± 0.3) × 105 copies/ml was used. For the rmPCR reactions, all targets were reproducibly amplified with a concentration of 1.1 (± 0.2) × 104 copies/ml of pSpn-RM1, and the PCR efficiency for each target was equivalent to DNA extracted from representative S. pneumoniae serotypes. CONCLUSIONS These quantifiable multi-target plasmids simplify the preparation of controls for PCR-based serotyping of S. pneumoniae, and methods herein could be extended to other highly multiplexed PCR assays.
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Affiliation(s)
- Jack Schembri
- Canadian Center for Vaccinology (CCfV) Dalhousie University, IWK Health Centre, and Nova Scotia Health Authority (NSHA), Halifax, Nova Scotia, Canada
| | - Hayley D Gillis
- Canadian Center for Vaccinology (CCfV) Dalhousie University, IWK Health Centre, and Nova Scotia Health Authority (NSHA), Halifax, Nova Scotia, Canada
| | - Amanda L S Lang
- Canadian Center for Vaccinology (CCfV) Dalhousie University, IWK Health Centre, and Nova Scotia Health Authority (NSHA), Halifax, Nova Scotia, Canada
| | - Michelle Warhuus
- Canadian Center for Vaccinology (CCfV) Dalhousie University, IWK Health Centre, and Nova Scotia Health Authority (NSHA), Halifax, Nova Scotia, Canada
| | - Irene Martin
- Streptococci and STI Unit, National Microbiology Laboratory (NML), Public Health Agency of Canada (PHAC), Winnipeg, Manitoba, Canada
| | - Walter Demczuk
- Streptococci and STI Unit, National Microbiology Laboratory (NML), Public Health Agency of Canada (PHAC), Winnipeg, Manitoba, Canada
| | - May ElSherif
- Canadian Center for Vaccinology (CCfV) Dalhousie University, IWK Health Centre, and Nova Scotia Health Authority (NSHA), Halifax, Nova Scotia, Canada
| | - Shelly A McNeil
- Canadian Center for Vaccinology (CCfV) Dalhousie University, IWK Health Centre, and Nova Scotia Health Authority (NSHA), Halifax, Nova Scotia, Canada
| | - Jason J LeBlanc
- Canadian Center for Vaccinology (CCfV) Dalhousie University, IWK Health Centre, and Nova Scotia Health Authority (NSHA), Halifax, Nova Scotia, Canada.
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8
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Dynamic transmission modelling to address infant pneumococcal conjugate vaccine schedule modifications in the UK. Epidemiol Infect 2018; 146:1797-1806. [PMID: 30012224 PMCID: PMC9506701 DOI: 10.1017/s095026881800198x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AbstractThe 13-valent pneumococcal conjugate vaccine (PCV) has been part of routine immunisation in a 2 + 1 schedule (two primary infant doses and one booster during the second year of life) in the UK since 2010. Recently, the UK's Joint Committee on Vaccination and Immunisation recommended changing to a 1 + 1 schedule while conceding that this will increase disease burden; however, uncertainty remains on how much pneumococcal burden – including invasive pneumococcal disease (IPD) and non-invasive disease – will increase. We built a dynamic transmission model to investigate this question. The model predicted that a 1 + 1 schedule would incur 8777–27 807 additional cases of disease and 241–743 more deaths over 5 years. Serotype 19A caused 55–71% of incremental IPD cases. Scenario analyses showed that booster dose adherence, effectiveness against carriage and waning in a 1 + 1 schedule had the most influence on resurgence of disease. Based on the model assumptions, switching to a 1 + 1 schedule will substantially increase disease burden. The results likely are conservative since they are based on relatively low vaccine-type pneumococcal transmission, a paradigm that has been called into question by data demonstrating an increase of IPD due to several vaccine serotypes during the last surveillance year available.
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9
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Comparison of traditional culture and molecular qPCR for detection of simultaneous carriage of multiple pneumococcal serotypes in African children. Sci Rep 2017; 7:4628. [PMID: 28680083 PMCID: PMC5498530 DOI: 10.1038/s41598-017-04915-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/22/2017] [Indexed: 11/29/2022] Open
Abstract
S. pneumoniae is a common colonizer of the human nasopharynx in high income and low-middle income countries. Due to limitations of standard culture methods, the prevalence of concurrent colonization with multiple serotypes is unclear. We evaluated the use of multiplex quantitative PCR (qPCR) to detect multiple pneumococcal serotypes/group colonization in archived nasopharyngeal swabs of pneumococcal conjugate vaccine naive children who had previously been investigated by traditional culture methods. Overall the detection of pneumococcal colonization was higher by qPCR (82%) compared to standard culture (71%; p < 0.001), with a high concordance (kappa = 0.73) of serotypes/groups identified by culture also being identified by qPCR. Also, qPCR was more sensitive in detecting multiple serotype/groups among colonized cases (28.7%) compared to culture (4.5%; p < 0.001). Of the additional serotypes detected only by qPCR, the majority were of lower density (<104 CFU/ml) than the dominant colonizing serotype, with serotype/group 6A/B, 19B/F and 23F being the highest density colonizers, followed by serotype 5 and serogroup 9A/L/N/V being the most common second and third colonizers respectively. The ability of qPCR to detect multiple pneumococcal serotypes at a low carriage density might provide better insight into underlying mechanism for changes in serotype colonization in PCV vaccinated children.
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10
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Cuevas RA, Eutsey R, Kadam A, West-Roberts JA, Woolford CA, Mitchell AP, Mason KM, Hiller NL. A novel streptococcal cell-cell communication peptide promotes pneumococcal virulence and biofilm formation. Mol Microbiol 2017; 105:554-571. [PMID: 28557053 DOI: 10.1111/mmi.13721] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2017] [Indexed: 12/29/2022]
Abstract
Streptococcus pneumoniae (pneumococcus) is a major human pathogen. It is a common colonizer of the human respiratory track, where it utilizes cell-cell communication systems to coordinate population-level behaviors. We reasoned that secreted peptides that are highly expressed during infection are pivotal for virulence. Thus, we used in silico pattern searches to define a pneumococcal secretome and analyzed the transcriptome of the clinically important PMEN1 lineage to identify which peptide-encoding genes are highly expressed in vivo. In this study, we characterized virulence peptide 1 (vp1), a highly expressed Gly-Gly peptide-encoding gene in chinchilla middle ear effusions. The vp1 gene is widely distributed across pneumococcus as well as encoded in related species. Studies in the chinchilla model of middle ear infection demonstrated that VP1 is a virulence determinant. The vp1 gene is positively regulated by a transcription factor from the Rgg family and its cognate SHP (short hydrophobic peptide). In vitro data indicated that VP1 promotes increased thickness and biomass for biofilms grown on chinchilla middle ear epithelial cells. Furthermore, the wild-type biofilm is restored with the exogenous addition of synthetic VP1. We conclude that VP1 is a novel streptococcal regulatory peptide that controls biofilm development and pneumococcal pathogenesis.
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Affiliation(s)
- Rolando A Cuevas
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Rory Eutsey
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Anagha Kadam
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jacob A West-Roberts
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Carol A Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Aaron P Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Kevin M Mason
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - N Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.,Center of Excellence in Biofilm Research, Allegheny Health Network, Pittsburgh, PA 15211, USA
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11
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Wang J, Leong MC, Leong EZW, Kuan WS, Leong DT. Clinically Relevant Detection of Streptococcus pneumoniae with DNA-Antibody Nanostructures. Anal Chem 2017; 89:6900-6906. [PMID: 28548485 DOI: 10.1021/acs.analchem.7b01508] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Streptococcus pneumoniae (SP) is a pathogenic bacterium and a major cause of community-acquired pneumonia that could be fatal if left untreated. Therefore, rapid and sensitive detection of SP is crucial to enable targeted treatment during SP infections. In this study, DNA tetrahedron (DNA TH) with a hollow structure is anchored on gold electrodes to construct an electrochemical immunosensor for rapid detection of pneumococcal surface protein A (PspA) peptide and SP lysate from synthetic and actual human samples. This DNA nanostructure-based immunosensor displays excellent electrochemical activity toward PspA with a sensitive linear region from 0 to 8 ng/mL of PspA peptide and a low limit of detection (LOD) of 0.218 ng/mL. In addition, this DNA-TH-based immunosensor exhibits good sensing performance toward SP lysate in a clinically relevant linear range from 5 to 100 CFU/mL with a LOD of 0.093 CFU/mL. Along with these attractive features, this electrochemical immunosensor is able to specifically recognize and detect the PspA peptide mixed with other physiologically relevant components like bovine serum albumin (BSA) and lipopolysaccharide. In addition, our sensor could detect SP lysate even when dispersed in BSA or Escherichia coli lysate. Lastly, uncultured samples from the nasal cavity, mouth, and axilla of a human subject could be successfully determined by this well-designed electrochemical immunosensor.
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Affiliation(s)
- Jinping Wang
- Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585, Singapore
| | - May Ching Leong
- Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Eric Zhe Wei Leong
- Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585, Singapore
| | - Win Sen Kuan
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117585, Singapore.,Emergency Medicine Department, National University Hospital, National University Health System , 5 Lower Kent Ridge Road, Singapore 119074, Singapore
| | - David Tai Leong
- Department of Chemical and Biomolecular Engineering, National University of Singapore , 4 Engineering Drive 4, Singapore 117585, Singapore
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12
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Steens A, Milhano N, Aaberge IS, Vestrheim DF. In vitro and in vivo comparison of transport media for detecting nasopharyngeal carriage of Streptococcus pneumoniae. PeerJ 2016; 4:e2449. [PMID: 27688966 PMCID: PMC5036082 DOI: 10.7717/peerj.2449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/15/2016] [Indexed: 11/20/2022] Open
Abstract
Background As a standard method for pneumococcal carriage studies, the World Health Organization recommends nasopharyngeal swabs be transported and stored at cool temperatures in a medium containing skim-milk, tryptone, glucose and glycerol (STGG). An enrichment broth used for transport at room temperature in three carriage studies performed in Norway may have a higher sensitivity than STGG. We therefore compared the media in vitro and in vivo. Methods For the in vitro component, three strains (serotype 4, 19F and 3) were suspended in STGG and enrichment broth. Recovery was compared using latex agglutination, quantification of bacterial loads by real-time PCR of the lytA gene, and counting colonies from incubated plates. For the in vivo comparison, paired swabs were obtained from 100 children and transported in STGG at cool temperatures or in enrichment broth at room temperature. Carriage was identified by latex agglutination and confirmed by Quellung reaction. Results In vitro, the cycle threshold values obtained by PCR did not differ between the two media (p = 0.853) and no clear difference in colony counts was apparent after incubation (p = 0.593). In vivo, pneumococci were recovered in 46% of swabs transported in STGG and 51% of those transported in enrichment broth (Kappa statistic 0.90, p = 0.063). Discussion Overall, no statistical differences in sensitivity were found between STGG and enrichment broth. Nevertheless, some serotype differences were observed and STGG appeared slightly less sensitive than enrichment broth for detection of nasopharyngeal carriage of pneumococci by culturing. We recommend the continued use of STGG for transport and storage of nasopharyngeal swabs in pneumococcal carriage studies for the benefit of comparability between studies and settings, including more resource-limited settings.
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Affiliation(s)
- Anneke Steens
- Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Natacha Milhano
- Infection Control and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway; European Programme for Public Health Microbiology Training (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Ingeborg S Aaberge
- Infection Control and Environmental Health, Norwegian Institute of Public Health , Oslo , Norway
| | - Didrik F Vestrheim
- Infection Control and Environmental Health, Norwegian Institute of Public Health , Oslo , Norway
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Cocolonization of Pneumococcal Serotypes in Healthy Children Attending Day Care Centers: Molecular Versus Conventional Methods. Pediatr Infect Dis J 2016; 35:477-80. [PMID: 26808723 DOI: 10.1097/inf.0000000000001059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Pneumococci are common colonizer, especially of children, and cocolonization of different serotypes is an important factor for intraspecies genetic exchange. The aim of this study was to analyze pneumococcal carriage and serotype distribution in unvaccinated healthy children in Iceland and compare conventional culture methods and molecular methods using DNA extracted directly from the samples. METHODS Nasopharyngeal swabs were obtained from 514 children aged 2-6 year attending day care centers in Reykjavik in 2009. The swabs were selectively cultured for pneumococci and the isolates serotyped using latex agglutination. DNA was also extracted directly from the swabs and serotyped using a multiplex PCR panel designed to detect vaccine serotypes and the most commonly carried non-vaccine serotypes. RESULT Pneumococcal carriage was detected in 391 (76.1%) of the children using polymerase chain reaction (PCR) and in 371 (72.2%) using conventional methods. Cocolonization was detected in 92 (23.5%) of the carriers when PCR method was used and in 30 (8.1%) when conventional methods were used, detecting 500 and 401 strains, respectively (P < 0.0001). The most common serotypes were 23F, 19A, 6B, 6A and 19F, rates 13-8%. The number of isolates of serotypes included in the 10-valent and 13-valent vaccines and detected by PCR were 234 (58.4%) and 363 (90.5%), respectively and by conventional methods 186 (46.4%) and 293 (73.1%), respectively. CONCLUSION Cocolonization was detected in a fourth of the children carrying pneumococci using DNA extracted directly from nasopharyngeal swabs. The rate of carriage was very high, but no serotype dominated, and the children were commonly colonized by vaccine serotypes, especially cocolonized children.
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Detection and prediction of Streptococcus pneumoniae serotypes directly from nasopharyngeal swabs using PCR. J Med Microbiol 2015; 64:836-844. [DOI: 10.1099/jmm.0.000097] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Domenech M, Damián D, Ardanuy C, Liñares J, Fenoll A, García E. Emerging, Non-PCV13 Serotypes 11A and 35B of Streptococcus pneumoniae Show High Potential for Biofilm Formation In Vitro. PLoS One 2015; 10:e0125636. [PMID: 25927917 PMCID: PMC4415931 DOI: 10.1371/journal.pone.0125636] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/20/2015] [Indexed: 01/20/2023] Open
Abstract
Background Since the use of pneumococcal conjugate vaccines PCV7 and PCV13 in children became widespread, invasive pneumococcal disease (IPD) has dramatically decreased. Nevertheless, there has been a rise in incidence of Streptococcus pneumoniae non-vaccine serotypes (NVT) colonising the human nasopharynx. Nasopharyngeal colonisation, an essential step in the development of S. pneumoniae-induced IPD, is associated with biofilm formation. Although the capsule is the main pneumococcal virulence factor, the formation of pneumococcal biofilms might, in fact, be limited by the presence of capsular polysaccharide (CPS). Methodology/Principal Findings We used clinical isolates of 16 emerging, non-PCV13 serotypes as well as isogenic transformants of the same serotypes. The biofilm formation capacity of isogenic transformants expressing CPSs from NVT was evaluated in vitro to ascertain whether this trait can be used to predict the emergence of NVT. Fourteen out of 16 NVT analysed were not good biofilm formers, presumably because of the presence of CPS. In contrast, serotypes 11A and 35B formed ≥45% of the biofilm produced by the non-encapsulated M11 strain. Conclusions/Significance This study suggest that emerging, NVT serotypes 11A and 35B deserve a close surveillance.
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Affiliation(s)
- Mirian Domenech
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Diana Damián
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Carmen Ardanuy
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Hospital Universitari de Bellvitge-Universitat de Barcelona-Fundació Privada Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Josefina Liñares
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Hospital Universitari de Bellvitge-Universitat de Barcelona-Fundació Privada Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Asunción Fenoll
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - Ernesto García
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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