1887

Abstract

Since the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) in Malawi in 2011, there has been persistent carriage of vaccine serotype (VT) , despite high vaccine coverage. To determine if there has been a genetic change within the VT capsule polysaccharide (cps) loci since the vaccine’s introduction, we compared 1022 whole-genome-sequenced VT isolates from 1998 to 2019. We identified the clonal expansion of a multidrug-resistant, penicillin non-susceptible serotype 23F GPSC14-ST2059 lineage, a serotype 14 GPSC9-ST782 lineage and a novel serotype 14 sequence type GPSC9-ST18728 lineage. Serotype 23F GPSC14-ST2059 had an I253T mutation within the capsule oligosaccharide repeat unit polymerase Wzy protein, which is predicted to alter the protein pocket cavity. Moreover, serotype 23F GPSC14-ST2059 had SNPs in the DNA binding sites for the cps transcriptional repressors CspR and SpxR. Serotype 14 GPSC9-ST782 harbours a non-truncated version of the large repetitive protein (Lrp), containing a Cna protein B-type domain which is also present in proteins associated with infection and colonisation. These emergent lineages also harboured genes associated with antibiotic resistance, and the promotion of colonisation and infection which were absent in other lineages of the same serotype. Together these data suggest that in addition to serotype replacement, modifications of the capsule locus associated with changes in virulence factor expression and antibiotic resistance may promote vaccine escape. In summary, the study highlights that the persistence of vaccine serotype carriage despite high vaccine coverage in Malawi may be partly caused by expansion of VT lineages post-PCV13 rollout.

Funding
This study was supported by the:
  • Wellcome Trust (Award 206545/Z/17/Z)
    • Principle Award Recipient: NotApplicable
  • Medical Research Council (Award MR/N023129/1)
    • Principle Award Recipient: NotApplicable
  • Bill and Melinda Gates Foundation (Award OPP1117653)
    • Principle Award Recipient: NotApplicable
  • This is an open-access article distributed under the terms of the Creative Commons Attribution License. This article was made open access via a Publish and Read agreement between the Microbiology Society and the corresponding author’s institution.
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2024-06-19
2024-07-15
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References

  1. Global Pneumococcal Disease and Vaccination | CDC [Internet]; 2023 https://www.cdc.gov/pneumococcal/global.html accessed 26 February 2024
  2. Wahl B, O’Brien KL, Greenbaum A, Majumder A, Liu L et al. Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccines: global, regional, and national estimates for 2000-15. Lancet Glob Health 2018; 6:e744–e757 [View Article] [PubMed]
    [Google Scholar]
  3. Rodgers GL, Whitney CG, Klugman KP. Triumph of pneumococcal conjugate vaccines: overcoming a common foe. J Infect Dis 2021; 224:S352–S359 [View Article] [PubMed]
    [Google Scholar]
  4. Berman-Rosa M, O’Donnell S, Barker M, Quach C. Efficacy and effectiveness of the PCV-10 and PCV-13 vaccines against invasive pneumococcal disease. Pediatrics 2020; 145:e20190377 [View Article] [PubMed]
    [Google Scholar]
  5. Wartha F, Beiter K, Albiger B, Fernebro J, Zychlinsky A et al. Capsule and D-alanylated lipoteichoic acids protect Streptococcus pneumoniae against neutrophil extracellular traps. Cell Microbiol 2007; 9:1162–1171 [View Article]
    [Google Scholar]
  6. Hyams C, Camberlein E, Cohen JM, Bax K, Brown JS. The Streptococcus pneumoniae capsule inhibits complement activity and neutrophil phagocytosis by multiple mechanisms. Infect Immun 2010; 78:704–715 [View Article] [PubMed]
    [Google Scholar]
  7. Abeyta M, Hardy GG, Yother J. Genetic alteration of capsule type but not PspA type affects accessibility of surface-bound complement and surface antigens of Streptococcus pneumoniae. Infect Immun 2003; 71:218–225 [View Article] [PubMed]
    [Google Scholar]
  8. Bentley SD, Aanensen DM, Mavroidi A, Saunders D, Rabbinowitsch E et al. Genetic analysis of the capsular biosynthetic locus from all 90 pneumococcal serotypes. PLoS Genet 2006; 2:e31 [View Article] [PubMed]
    [Google Scholar]
  9. GPS:: Global Pneumococcal Sequencing Project [Internet]. n.d https://www.pneumogen.net/gps/serotypes.html accessed 28 September 2023
  10. Flasche S, Van Hoek AJ, Sheasby E, Waight P, Andrews N et al. Effect of pneumococcal conjugate vaccination on serotype-specific carriage and invasive disease in England: A cross-sectional study. PLoS Med 2011; 8:e1001017 [View Article] [PubMed]
    [Google Scholar]
  11. Bar-Zeev N, Swarthout TD, Everett DB, Alaerts M, Msefula J et al. Impact and effectiveness of 13-valent pneumococcal conjugate vaccine on population incidence of vaccine and non-vaccine serotype invasive pneumococcal disease in Blantyre, Malawi, 2006–18: prospective observational time-series and case-control studies. Lancet Global Health 2021; 9:e989–e998 [View Article]
    [Google Scholar]
  12. Koenraads M, Swarthout TD, Bar-Zeev N, Brown C, Msefula J et al. Changing incidence of invasive pneumococcal disease in infants less than 90 days of age before and after introduction of the 13-valent pneumococcal conjugate vaccine in Blantyre, Malawi: A 14-year Hospital Based Surveillance Study. Pediatr Infect Dis J 2022; 41:764–768 [View Article] [PubMed]
    [Google Scholar]
  13. Swarthout TD, Fronterre C, Lourenço J, Obolski U, Gori A et al. High residual carriage of vaccine-serotype Streptococcus pneumoniae after introduction of pneumococcal conjugate vaccine in Malawi. Nat Commun 2020; 11:2222 [View Article] [PubMed]
    [Google Scholar]
  14. Swarthout TD, Henrion MYR, Thindwa D, Meiring JE, Mbewe M et al. Waning of antibody levels induced by a 13-valent pneumococcal conjugate vaccine, using a 3 + 0 schedule, within the first year of life among children younger than 5 years in Blantyre, Malawi: an observational, population-level, serosurveillance study. Lancet Infect Dis 2022; 22:1737–1747 [View Article] [PubMed]
    [Google Scholar]
  15. Mostowy RJ, Croucher NJ, De Maio N, Chewapreecha C, Salter SJ et al. Pneumococcal capsule synthesis locus cps as evolutionary hotspot with potential to generate novel serotypes by recombination. Mol Biol Evol 2017; 34:2537–2554 [View Article] [PubMed]
    [Google Scholar]
  16. Tsang R. Capsule switching and capsule replacement in vaccine-preventable bacterial diseases. Lancet Infect Dis 2007; 7:569–570 [View Article] [PubMed]
    [Google Scholar]
  17. Roca A, Bojang A, Bottomley C, Gladstone RA, Adetifa JU et al. Effect on nasopharyngeal pneumococcal carriage of replacing PCV7 with PCV13 in the expanded programme of immunization in The Gambia. Vaccine 2015; 33:7144–7151 [View Article] [PubMed]
    [Google Scholar]
  18. Park IH, Pritchard DG, Cartee R, Brandao A, Brandileone MCC et al. Discovery of a new capsular serotype (6C) within serogroup 6 of Streptococcus pneumoniae. J Clin Microbiol 2007; 45:1225–1233 [View Article] [PubMed]
    [Google Scholar]
  19. Oliver MB, van der Linden MPG, Küntzel SA, Saad JS, Nahm MH. Discovery of Streptococcus pneumoniae serotype 6 variants with glycosyltransferases synthesizing two differing repeating units. J Biol Chem 2013; 288:25976–25985 [View Article] [PubMed]
    [Google Scholar]
  20. Arends DW, Miellet WR, Langereis JD, Ederveen THA, van der Gaast-de Jongh CE et al. Examining the distribution and impact of single-nucleotide polymorphisms in the capsular locus of Streptococcus pneumoniae serotype 19A. Infect Immun 2021; 89:e0024621 [View Article] [PubMed]
    [Google Scholar]
  21. Lo SW, Gladstone RA, van Tonder AJ, Lees JA, du Plessis M et al. Pneumococcal lineages associated with serotype replacement and antibiotic resistance in childhood invasive pneumococcal disease in the post-PCV13 era: an international whole-genome sequencing study. Lancet Infect Dis 2019; 19:759–769 [View Article] [PubMed]
    [Google Scholar]
  22. Iroh Tam P-Y, Chirombo J, Henrion M, Newberry L, Mambule I et al. Clinical pneumonia in the hospitalised child in Malawi in the post-pneumococcal conjugate vaccine era: a prospective hospital-based observational study. BMJ Open 2022; 12:e050188 [View Article] [PubMed]
    [Google Scholar]
  23. Chaguza C, Cornick JE, Andam CP, Gladstone RA, Alaerts M et al. Population genetic structure, antibiotic resistance, capsule switching and evolution of invasive pneumococci before conjugate vaccination in Malawi. Vaccine 2017; 35:4594–4602 [View Article]
    [Google Scholar]
  24. Musicha P, Cornick JE, Bar-Zeev N, French N, Masesa C et al. Trends in antimicrobial resistance in bloodstream infection isolates at a large urban hospital in Malawi (1998-2016): a surveillance study. Lancet Infect Dis 2017; 17:1042–1052 [View Article] [PubMed]
    [Google Scholar]
  25. Bar-Zeev N, Kapanda L, King C, Beard J, Phiri T et al. Methods and challenges in measuring the impact of national pneumococcal and rotavirus vaccine introduction on morbidity and mortality in Malawi. Vaccine 2015; 33:2637–2645 [View Article]
    [Google Scholar]
  26. Obolski U, Swarthout TD, Kalizang’oma A, Mwalukomo TS, Chan JM et al. The metabolic, virulence and antimicrobial resistance profiles of colonising Streptococcus pneumoniae shift after PCV13 introduction in urban Malawi. Nat Commun 2023; 14:7477 [View Article] [PubMed]
    [Google Scholar]
  27. Gladstone RA, Lo SW, Lees JA, Croucher NJ, van Tonder AJ et al. International genomic definition of pneumococcal lineages, to contextualise disease, antibiotic resistance and vaccine impact. EBioMedicine 2019; 43:338–346 [View Article]
    [Google Scholar]
  28. Lees JA, Harris SR, Tonkin-Hill G, Gladstone RA, Lo SW et al. Fast and flexible bacterial genomic epidemiology with PopPUNK. Genome Res 2019; 29:304–316 [View Article]
    [Google Scholar]
  29. Enright MC, Spratt BG. A multilocus sequence typing scheme for Streptococcus pneumoniae: identification of clones associated with serious invasive disease. Microbiology 1998; 144:3049–3060 [View Article]
    [Google Scholar]
  30. Schwengers O, Jelonek L, Dieckmann MA, Beyvers S, Blom J et al. Bakta: rapid and standardized annotation of bacterial genomes via alignment-free sequence identification. Microb Genomics 2021; 7000685 [View Article]
    [Google Scholar]
  31. Minh BQ, Schmidt HA, Chernomor O, Schrempf D, Woodhams MD et al. IQ-TREE 2: new models and efficient methods for phylogenetic inference in the genomic era. Mol Biol Evol 2020; 37:1530–1534 [View Article] [PubMed]
    [Google Scholar]
  32. Kalyaanamoorthy S, Minh BQ, Wong TKF, von Haeseler A, Jermiin LS. ModelFinder: fast model selection for accurate phylogenetic estimates. Nat Methods 2017; 14:587–589 [View Article] [PubMed]
    [Google Scholar]
  33. Xu S, Li L, Luo X, Chen M, Tang W et al. Ggtree: A serialized data object for visualization of A phylogenetic tree and annotation data. iMeta 2022; 1:e56 [View Article]
    [Google Scholar]
  34. McGinnis S, Madden TL. BLAST: at the core of a powerful and diverse set of sequence analysis tools. Nucleic Acids Res 2004; 32:W20–5 [View Article] [PubMed]
    [Google Scholar]
  35. Li H. Minimap2: pairwise alignment for nucleotide sequences. Bioinformatics 2018; 34:3094–3100 [View Article] [PubMed]
    [Google Scholar]
  36. Glanville DG, Gazioglu O, Marra M, Tokars VL, Kushnir T et al. Pneumococcal capsule expression is controlled through a conserved, distal cis-regulatory element during infection. PLoS Pathog 2023; 19:e1011035 [View Article] [PubMed]
    [Google Scholar]
  37. Quinlan AR, Hall IM. BEDTools: a flexible suite of utilities for comparing genomic features. Bioinformatics 2010; 26:841–842 [View Article] [PubMed]
    [Google Scholar]
  38. Sievers F, Higgins DG. Clustal omega for making accurate alignments of many protein sequences. Protein Sci Publ Protein Soc 2018; 27:135–145 [View Article]
    [Google Scholar]
  39. Schwede T, Kopp J, Guex N, Peitsch MC. SWISS-MODEL: an automated protein homology-modeling server. Nucleic Acids Res 2003; 31:3381–3385 [View Article] [PubMed]
    [Google Scholar]
  40. Bernhofer M, Rost B. TMbed: transmembrane proteins predicted through language model embeddings. BMC Bioinformatics 2022; 23:326 [View Article] [PubMed]
    [Google Scholar]
  41. Krivák R, Hoksza D. P2Rank: machine learning based tool for rapid and accurate prediction of ligand binding sites from protein structure. J Cheminform 2018; 10:39 [View Article]
    [Google Scholar]
  42. Ittisoponpisan S, Islam SA, Khanna T, Alhuzimi E, David A et al. Can predicted protein 3D structures provide reliable insights into whether missense variants are disease associated?. J Mol Biol 2019; 431:2197–2212 [View Article] [PubMed]
    [Google Scholar]
  43. Jakubec D, Skoda P, Krivak R, Novotny M, Hoksza D. PrankWeb 3: accelerated ligand-binding site predictions for experimental and modelled protein structures. Nucleic Acids Res 2022; 50:W593–W597 [View Article] [PubMed]
    [Google Scholar]
  44. Croucher NJ, Page AJ, Connor TR, Delaney AJ, Keane JA et al. Rapid phylogenetic analysis of large samples of recombinant bacterial whole genome sequences using Gubbins. Nucleic Acids Res 2015; 43:e15 [View Article] [PubMed]
    [Google Scholar]
  45. Argimón S, Abudahab K, Goater RJE, Fedosejev A, Bhai J et al. Microreact: visualizing and sharing data for genomic epidemiology and phylogeography. Microbial Genomics 2016; 2:e000093 [View Article]
    [Google Scholar]
  46. Helekal D, Ledda A, Volz E, Wyllie D, Didelot X. Bayesian inference of clonal expansions in a dated phylogeny. Syst Biol 2022; 71:1073–1087 [View Article] [PubMed]
    [Google Scholar]
  47. Tonkin-Hill G, MacAlasdair N, Ruis C, Weimann A, Horesh G et al. Producing polished prokaryotic pangenomes with the Panaroo pipeline. Genome Biol 2020; 21:180 [View Article] [PubMed]
    [Google Scholar]
  48. Brynildsrud O, Bohlin J, Scheffer L, Eldholm V. Rapid scoring of genes in microbial pan-genome-wide association studies with Scoary. Genome Biol 2016; 17:238 [View Article] [PubMed]
    [Google Scholar]
  49. Wang J, Santiago E, Caballero A. Prediction and estimation of effective population size. Heredity 2016; 117:193–206 [View Article] [PubMed]
    [Google Scholar]
  50. Didelot X, Croucher NJ, Bentley SD, Harris SR, Wilson DJ. Bayesian inference of ancestral dates on bacterial phylogenetic trees. Nucleic Acids Res 2018; 46:e134 [View Article]
    [Google Scholar]
  51. Chan WT, Moreno-Córdoba I, Yeo CC, Espinosa M. Toxin-antitoxin genes of the gram-positive pathogen Streptococcus pneumoniae: so few and yet so many. Microbiol Mol Biol Rev 2012; 76:773–791 [View Article]
    [Google Scholar]
  52. Chan W, Domenech M, Moreno-Córdoba I, Navarro-Martínez V, Nieto C et al. The Streptococcus pneumoniae yefM-yoeB and relBE toxin-antitoxin operons participate in oxidative stress and biofilm formation. Toxins 2018; 10:378 [View Article]
    [Google Scholar]
  53. Bandara M, Skehel JM, Kadioglu A, Collinson I, Nobbs AH et al. The accessory Sec system (SecY2A2) in Streptococcus pneumoniae is involved in export of pneumolysin toxin, adhesion and biofilm formation. Microbes Infect 2017; 19:402–412 [View Article] [PubMed]
    [Google Scholar]
  54. Lizcano A, Akula Suresh Babu R, Shenoy AT, Saville AM, Kumar N et al. Transcriptional organization of pneumococcal psrP-secY2A2 and impact of GtfA and GtfB deletion on PsrP-associated virulence properties. Microbes Infect 2017; 19:323–333 [View Article] [PubMed]
    [Google Scholar]
  55. Rose L, Shivshankar P, Hinojosa E, Rodriguez A, Sanchez CJ et al. Antibodies against PsrP, a novel Streptococcus pneumoniae adhesin, block adhesion and protect mice against pneumococcal challenge. J Infect Dis 2008; 198:375–383 [View Article] [PubMed]
    [Google Scholar]
  56. Sonja L, Nicholas JC, François B, Christophe F. Epidemiological dynamics of bacteriocin competition and antibiotic resistance. Proc Biol Sci 2022; 289:
    [Google Scholar]
  57. Glover DT, Hollingshead SK, Briles DE. Streptococcus pneumoniae surface protein PcpA elicits protection against lung infection and fatal sepsis. Infect Immun 2008; 76:2767–2776 [View Article] [PubMed]
    [Google Scholar]
  58. Blue CE, Paterson GK, Kerr AR, Bergé M, Claverys JP et al. ZmpB, a novel virulence factor of Streptococcus pneumoniae that induces tumor necrosis factor alpha production in the respiratory tract. Infect Immun 2003; 71:4925–4935 [View Article] [PubMed]
    [Google Scholar]
  59. Cornick JE, Everett DB, Broughton C, Denis BB, Banda DL et al. Invasive Streptococcus pneumoniae in children, Malawi, 2004-2006. Emerg Infect Dis 2011; 17:1107–1109 [View Article] [PubMed]
    [Google Scholar]
  60. Donkor ES, Adegbola RA, Wren BW, Antonio M. Population biology of Streptococcus pneumoniae in West Africa: multilocus sequence typing of serotypes that exhibit different predisposition to invasive disease and carriage. PLoS One 2013; 8:e53925 [View Article] [PubMed]
    [Google Scholar]
  61. Ma X, Yao KH, Yu SJ, Zhou L, Li QH et al. Genotype replacement within serotype 23F Streptococcus pneumoniae in Beijing, China: characterization of serotype 23F. Epidemiol Infect 2013; 141:1690–1696 [View Article] [PubMed]
    [Google Scholar]
  62. Manenzhe RI, Dube FS, Wright M, Lennard K, Mounaud S et al. Characterization of pneumococcal colonization dynamics and antimicrobial resistance using shotgun metagenomic sequencing in intensively sampled South African infants. Front Public Health 2020; 8:543898 [View Article] [PubMed]
    [Google Scholar]
  63. Wen Z, Liu Y, Qu F, Zhang JR. Allelic variation of the capsule promoter diversifies encapsulation and virulence in Streptococcus pneumoniae. Sci Rep 2016; 6:30176 [View Article] [PubMed]
    [Google Scholar]
  64. Jiang SM, Wang L, Reeves PR. Molecular characterization of Streptococcus pneumoniae type 4, 6B, 8, and 18C capsular polysaccharide gene clusters. Infect Immun 2001; 69:1244–1255 [View Article] [PubMed]
    [Google Scholar]
  65. Islam ST, Huszczynski SM, Nugent T, Gold AC, Lam JS. Conserved-residue mutations in Wzy affect O-antigen polymerization and Wzz-mediated chain-length regulation in Pseudomonas aeruginosa PAO1. Sci Rep 2013; 3:3441 [View Article] [PubMed]
    [Google Scholar]
  66. Daniels C, Vindurampulle C, Morona R. Overexpression and topology of theShigella flexneriO‐antigen polymerase (Rfc/Wzy). Mol Microbiol 1998; 28:1211–1222 [View Article]
    [Google Scholar]
  67. Zhu J, Abruzzo AR, Wu C, Bee GCW, Pironti A et al. Effects of capsular polysaccharide amount on pneumococcal-host interactions. PLoS Pathog 2023; 19:e1011509 [View Article] [PubMed]
    [Google Scholar]
  68. Hawkins PA, Chochua S, Lo SW, Belman S, Antonio M et al. A global genomic perspective on the multidrug-resistant Streptococcus pneumoniae 15A-CC63 sub-lineage following pneumococcal conjugate vaccine introduction. Microb Genomics 2023; 9:000998 [View Article]
    [Google Scholar]
  69. Moore CE, Giess A, Soeng S, Sar P, Kumar V et al. Characterisation of invasive Streptococcus pneumoniae isolated from Cambodian children between 2007 - 2012. PLoS One 2016; 11:e0159358 [View Article] [PubMed]
    [Google Scholar]
  70. Yamba Yamba L, Uddén F, Fuursted K, Ahl J, Slotved HC et al. Extensive/multidrug-resistant pneumococci detected in clinical respiratory tract samples in Southern Sweden are closely related to international multidrug-resistant lineages. Front Cell Infect Microbiol 2022; 12:824449 [View Article] [PubMed]
    [Google Scholar]
  71. Manna S, Spry L, Wee-Hee A, Ortika BD, Boelsen LK et al. Variants of Streptococcus pneumoniae serotype 14 from Papua New Guinea with the potential to be mistyped and escape vaccine-induced protection. Microbiol Spectr 2022; 10:e0152422 [View Article] [PubMed]
    [Google Scholar]
  72. van Tonder AJ, Bray JE, Quirk SJ, Haraldsson G, Jolley KA et al. Putatively novel serotypes and the potential for reduced vaccine effectiveness: capsular locus diversity revealed among 5405 pneumococcal genomes. Microbial Genomics 2016; 2: [View Article]
    [Google Scholar]
  73. Muñoz R, Coffey TJ, Daniels M, Dowson CG, Laible G et al. Intercontinental spread of a multiresistant clone of serotype 23F Streptococcus pneumoniae. J Infect Dis 1991; 164:302–306 [View Article] [PubMed]
    [Google Scholar]
  74. De Lencastre H, Tomasz A. From ecological reservoir to disease: the nasopharynx, day-care centres and drug-resistant clones of Streptococcus pneumoniae. J Antimicrob Chemother 2002; 50 Suppl S2:75–81 [View Article] [PubMed]
    [Google Scholar]
  75. Coffey TJ, Dowson CG, Daniels M, Zhou J, Martin C et al. Horizontal transfer of multiple penicillin-binding protein genes, and capsular biosynthetic genes, in natural populations of Streptococcus pneumoniae. Mol Microbiol 1991; 5:2255–2260 [View Article] [PubMed]
    [Google Scholar]
  76. Wyres KL, Lambertsen LM, Croucher NJ, McGee L, von Gottberg A et al. The multidrug-resistant PMEN1 pneumococcus is a paradigm for genetic success. Genome Biol 2012; 13:R103 [View Article] [PubMed]
    [Google Scholar]
  77. Gladstone RA, Lo SW, Lees JA, Croucher NJ, van Tonder AJ et al. International genomic definition of pneumococcal lineages, to contextualise disease, antibiotic resistance and vaccine impact. eBioMedicine 2019; 43:338–346 [View Article] [PubMed]
    [Google Scholar]
  78. Weiser JN, Ferreira DM, Paton JC. Streptococcus pneumoniae: transmission, colonization and invasion. Nat Rev Microbiol 2018; 16:355–367 [View Article] [PubMed]
    [Google Scholar]
  79. Kirolos A, Swarthout TD, Mataya AA, Bonomali F, Brown C et al. Invasiveness potential of pneumococcal serotypes in children after introduction of PCV13 in Blantyre, Malawi. BMC Infect Dis 2023; 23:56 [View Article] [PubMed]
    [Google Scholar]
  80. Lourenço J, Obolski U, Swarthout TD, Gori A, Bar-Zeev N et al. Determinants of high residual post-PCV13 pneumococcal vaccine-type carriage in Blantyre, Malawi: a modelling study. BMC Med 2019; 17:219 [View Article] [PubMed]
    [Google Scholar]
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