Generation of genic diversity among Streptococcus pneumoniae strains via horizontal gene transfer during a chronic polyclonal pediatric infection
| العنوان: | Generation of genic diversity among Streptococcus pneumoniae strains via horizontal gene transfer during a chronic polyclonal pediatric infection |
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| المؤلفون: | N. Luisa Hiller, Azad Ahmed, Evan Powell, Darren P. Martin, Rory Eutsey, Josh Earl, Benjamin Janto, Robert J. Boissy, Justin Hogg, Karen Barbadora, Rangarajan Sampath, Shaun Lonergan, J. Christopher Post, Fen Z. Hu, Garth D. Ehrlich |
| المساهمون: | Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences |
| المصدر: | PLoS Pathogens PLoS Pathogens, Vol 6, Iss 9, p e1001108 (2010) PLoS One |
| سنة النشر: | 2010 |
| مصطلحات موضوعية: | Computational Biology/Comparative Sequence Analysis, medicine.disease_cause, Infectious Diseases/Bacterial Infections, Sequence alignment, lcsh:QH301-705.5, Respiratory Tract Infections, Phylogeny, Recombination, Genetic, 0303 health sciences, Sequence analysis, Horizontal gene transfer, 3. Good health, Phylogenetics, Streptococcus pneumoniae, Evolutionary Biology/Microbial Evolution and Genomics, Genetics and Genomics/Comparative Genomics, Research Article, lcsh:Immunologic diseases. Allergy, Gene Transfer, Horizontal, DNA recombination, Genetic loci, Immunology, Pediatric infection, Biology, Computer Science/Applications, Microbiology, Polymorphism, Single Nucleotide, Pneumococcal Infections, 03 medical and health sciences, Virology, Genetics, medicine, Humans, Molecular Biology, Alleles, 030304 developmental biology, Mucous Membrane, 030306 microbiology, Respiratory infections, Genetic Variation, Infant, Microbiology/Medical Microbiology, Genome analysis, Gene Expression Regulation, Bacterial, lcsh:Biology (General), Polyclonal antibodies, Chronic Disease, biology.protein, Parasitology, lcsh:RC581-607, Genome, Bacterial |
| الوصف: | Although there is tremendous interest in understanding the evolutionary roles of horizontal gene transfer (HGT) processes that occur during chronic polyclonal infections, to date there have been few studies that directly address this topic. We have characterized multiple HGT events that most likely occurred during polyclonal infection among nasopharyngeal strains of Streptococcus pneumoniae recovered from a child suffering from chronic upper respiratory and middle-ear infections. Whole genome sequencing and comparative genomics were performed on six isolates collected during symptomatic episodes over a period of seven months. From these comparisons we determined that five of the isolates were genetically highly similar and likely represented a dominant lineage. We analyzed all genic and allelic differences among all six isolates and found that all differences tended to occur within contiguous genomic blocks, suggestive of strain evolution by homologous recombination. From these analyses we identified three strains (two of which were recovered on two different occasions) that appear to have been derived sequentially, one from the next, each by multiple recombination events. We also identified a fourth strain that contains many of the genomic segments that differentiate the three highly related strains from one another, and have hypothesized that this fourth strain may have served as a donor multiple times in the evolution of the dominant strain line. The variations among the parent, daughter, and grand-daughter recombinant strains collectively cover greater than seven percent of the genome and are grouped into 23 chromosomal clusters. While capturing in vivo HGT, these data support the distributed genome hypothesis and suggest that a single competence event in pneumococci can result in the replacement of DNA at multiple non-adjacent loci. Author Summary Bacterial infections have long been studied using Koch's postulates wherein the paradigm is that a single clone leads to a given infection. Over the past decade, it has become clear that chronic bacterial infections often do not fit this paradigm. Instead these are associated with the presence of multiple strains or species (polyclonal) of bacteria that are organized into highly structured communities, termed biofilms, which can persist in the body and are recalcitrant to antibiotic treatment. In addition, there is extensive evidence that bacteria can incorporate genes from neighboring bacteria into their own genomes. This process can produce new strains and is known as horizontal gene transfer. In this study, we investigated for the first time, the tempo and relevance of gene transfer among bacterial strains of Streptococcus pneumoniae during a naturally occurring chronic childhood infection. We identified extensive gene transfer among multiple infecting strains, by sequencing of isolates recovered sequentially over a seven-month period. This gene transfer may serve as a counterpoint to the host's adaptive immune response and help explain the phenomenon of bacterial persistence, since, as occurs with some chronic viral and parasitic infections, the immune system may become overwhelmed by a set of related strains. |
| وصف الملف: | application/pdf |
| تدمد: | 1553-7374 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1669bcb1c55b4541e698477e24ffd036Test https://pubmed.ncbi.nlm.nih.gov/20862314Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....1669bcb1c55b4541e698477e24ffd036 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15537374 |
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