Group A Streptococcus Gene Expression in Humans with Pharyngitis Using a Microarray
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ABSTRACT:
ORGANISM(S): Streptococcus pyogenes SSI-1 Streptococcus pyogenes MGAS10750 Streptococcus pyogenes M1 GAS Streptococcus pyogenes MGAS6180 Streptococcus pyogenes MGAS315 Streptococcus pyogenes MGAS5005 Streptococcus pyogenes MGAS9429 Homo sapiens Streptococcus pyogenes MGAS2096
PROVIDER: GSE22436 | GEO | 2010/11/01
SECONDARY ACCESSION(S): PRJNA128543
REPOSITORIES: GEO
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Project description:This study represents the first in vivo genome wide analysis of gene epxression of Group A Streptococcus (GAS) in humans with pharyngitis. The micorarray used is a custom microarray that relies on an electrochemical reaction as the measured signal rather than flourescence. Distinct clusters of gene expression were discovered and analyzed. A functional analysis examining differences and similarities between the clusters was performed. Samples were taken from pediatric patients who had received a throat swab as part of their clinical care for evaluating pharyngitis. Eleven samples that were culture postive for GAS were used along with 3 samples from subjects who were GAS culture negative. The microarray was a composite comprised of 12,000 probes, representing 2724 GAS open reading frames belonging to serotypes M1, M3, M4, M12, and M28. There were 1671 probe sets that were homologous for the M1 serotype and represented over 95% of the total predicted coding region. Probe sets were 30-40mers in length and were selected using a Combimatrix probe selection algorithm taking into account gene (>90% BLAST score) and serotype specificity, Tm, hairpins and GC content. In addition, 70 Combimatrix built in probes were used as negative controls for background subtraction.
2010-11-01 | E-GEOD-22436 | biostudies-arrayexpress
Project description:Current diagnostic methods used to evaluate patients with pharyngitis for the presence of group A Streptococcus (GAS) do not discriminate between acute infection and asymptomatic carriage, potentially resulting in overuse of antibiotics. Host response as measured by the transcriptomic profile of peripheral blood leukocytes could make this distinction, and could also distinguish between GAS and viral infection. We used RNA sequencing to generate transcriptomes from whole blood samples from 37 children, including 10 with acute GAS pharyngitis, 5 asymptomatic GAS carriers, 3 with adenoviral pharyngitis, 3 with pharyngitis of unknown etiology, and 16 asymptomatic children negative for GAS. Transcriptional profiles from each group were distinct . 1357 genes were upregulated in the children with symptomatic GAS compared to those with asymptomatic carriage. A panel of 13 genes distinguished between children with acute GAS and all others with 91% accuracy. The gene encoding CD177, a marker of neutrophil activation, was markedly overexpressed in children with acute GAS and has potential as a diagnostic biomarker. We conclude that measurement of host response is highly promising to improve the diagnosis of GAS pharyngitis and could help limit unnecessary antibiotic use.
2021-01-01 | GSE158163 | GEO
Project description:The molecular genetic mechanisms used by bacteria to persist in humans are poorly understood. Group A Streptococcus (GAS) causes the majority of bacterial pharyngitis cases in humans and is prone to persistently inhabit the upper respiratory tract. To gain information about how GAS survives in and infects the oropharynx, we analyzed the transcriptome of a serotype M1 strain grown in saliva. The dynamic pattern of changes in transcripts of genes [spy0874/0875, herein named sptR and sptS (sptR/S), for saliva persistence] encoding a two-component gene regulatory system of unknown function suggested that SptR/S contributed to persistence of GAS in saliva. Consistent with this idea, an isogenic nonpolar mutant strain (DeltasptR) was dramatically less able to survive in saliva compared with the parental strain. Iterative expression microarray analysis of bacteria grown in saliva revealed that transcripts of several known and putative GAS virulence factor genes were decreased significantly in the DeltasptR mutant strain. Compared with the parental strain, the isogenic mutant strain also had altered transcripts of multiple genes encoding proteins involved in complex carbohydrate acquisition and utilization pathways. Western immunoblot analysis and real-time PCR analysis of GAS in throat swabs taken from humans with pharyngitis confirmed the findings. We conclude that SptR/S optimizes persistence of GAS in human saliva, apparently by strategically influencing metabolic pathways and virulence factor production. The discovery of a genetic program that significantly increased persistence of a major human pathogen in saliva enhances understanding of how bacteria survive in the host and suggests new therapeutic strategies.
2009-05-16 | GSE16124 | GEO
Project description:The molecular genetic mechanisms used by bacteria to persist in humans are poorly understood. Group A Streptococcus (GAS) causes the majority of bacterial pharyngitis cases in humans and is prone to persistently inhabit the upper respiratory tract. To gain information about how GAS survives in and infects the oropharynx, we analyzed the transcriptome of a serotype M1 strain grown in saliva. The dynamic pattern of changes in transcripts of genes [spy0874/0875, herein named sptR and sptS (sptR/S), for saliva persistence] encoding a two-component gene regulatory system of unknown function suggested that SptR/S contributed to persistence of GAS in saliva. Consistent with this idea, an isogenic nonpolar mutant strain (DeltasptR) was dramatically less able to survive in saliva compared with the parental strain. Iterative expression microarray analysis of bacteria grown in saliva revealed that transcripts of several known and putative GAS virulence factor genes were decreased significantly in the DeltasptR mutant strain. Compared with the parental strain, the isogenic mutant strain also had altered transcripts of multiple genes encoding proteins involved in complex carbohydrate acquisition and utilization pathways. Western immunoblot analysis and real-time PCR analysis of GAS in throat swabs taken from humans with pharyngitis confirmed the findings. We conclude that SptR/S optimizes persistence of GAS in human saliva, apparently by strategically influencing metabolic pathways and virulence factor production. The discovery of a genetic program that significantly increased persistence of a major human pathogen in saliva enhances understanding of how bacteria survive in the host and suggests new therapeutic strategies. We determined the transcriptome of SptR (spy0874) in human saliva by comparing expression microarray date for parental wild-type strain MGAS5005 and its delta-spy0874 isogenic mutant strain. 4 replicates of each strain were grown to mid-exponential and stationary growth phases in human saliva. RNA was isolated, converted to cDNA, labeled and hybridized to a custom-made Affymetrix GeneChip. Data was analyzed using GCOS.
2010-05-19 | E-GEOD-16124 | biostudies-arrayexpress
Project description:Identification of the genetic events that contribute to host-pathogen interactions is important for understanding the natural history of infectious diseases and developing therapeutics. Transcriptome studies conducted on pathogens have been central to this goal in recent years. However, most of these investigations have focused on specific end points or disease phases, rather than analysis of the entire time course of infection. To gain a more complete understanding of how bacterial gene expression changes over time in a primate host, the transcriptome of group A Streptococcus (GAS) was analyzed during an 86-day infection protocol in 20 cynomolgus macaques with experimental pharyngitis. The study used 260 custom Affymetrix (Santa Clara, CA) chips, and data were confirmed by TaqMan analysis. Colonization, acute, and asymptomatic phases of disease were identified. Successful colonization and severe inflammation were significantly correlated with an early onset of superantigen gene expression. The differential expression of two-component regulators covR and spy0680 (M1_spy0874) was significantly associated with GAS colony-forming units, inflammation, and phases of disease. Prophage virulence gene expression and prophage induction occurred predominantly during high pathogen cell densities and acute inflammation. We discovered that temporal changes in the GAS transcriptome were integrally linked to the phase of clinical disease and host-defense response. Knowledge of the gene expression patterns characterizing each phase of pathogen-host interaction provides avenues for targeted investigation of proven and putative virulence factors and genes of unknown function and will assist vaccine research. Keywords: other
2005-06-17 | GSE2713 | GEO
Project description:Relatively little is understood about the dynamics of global host–pathogen transcriptome changes that occur during bacterial infection of mucosal surfaces. To test the hypothesis that group A Streptococcus (GAS) infection of the oropharynx provokes a host transcriptome response, we performed genome-wide transcriptome analysis using a nonhuman primate model of experimental pharyngitis. We also identified host and pathogen biological processes and individual host and pathogen gene pairs with correlated patterns of expression, suggesting interaction. For this study, 509 host genes and seven biological pathways were differentially expressed throughout the entire 32-day infection cycle. GAS infection produced an initial widespread significant decrease in expression of many host genes, including those involved in cytokine production, vesicle formation, metabolism, and signal transduction. This repression lasted until day 4, at which time a large increase in expression of host genes was observed, including those involved in protein translation, antigen presentation, and GTP-mediated signaling. The interactome analysis identified 73 host and pathogen gene pairs with correlated expression levels. We discovered significant correlations between transcripts of GAS genes involved in hyaluronic capsule production and host endocytic vesicle formation, GAS GTPases and host fibrinolytic genes, and GAS response to interaction with neutrophils. We also identified a strong signal, suggesting interaction between host γδ T cells and genes in the GAS mevalonic acid synthesis pathway responsible for production of isopentenyl-pyrophosphate, a short-chain phospholipid that stimulates these T cells. Taken together, our Q:2 results are unique in providing a comprehensive understanding of the host–pathogen interactome during mucosal infection by a bacterial pathogen.
2010-03-18 | GSE20262 | GEO
Project description:Relatively little is understood about the dynamics of global hostâpathogen transcriptome changes that occur during bacterial infection of mucosal surfaces. To test the hypothesis that group A Streptococcus (GAS) infection of the oropharynx provokes a host transcriptome response, we performed genome-wide transcriptome analysis using a nonhuman primate model of experimental pharyngitis. We also identified host and pathogen biological processes and individual host and pathogen gene pairs with correlated patterns of expression, suggesting interaction. For this study, 509 host genes and seven biological pathways were differentially expressed throughout the entire 32-day infection cycle. GAS infection produced an initial widespread significant decrease in expression of many host genes, including those involved in cytokine production, vesicle formation, metabolism, and signal transduction. This repression lasted until day 4, at which time a large increase in expression of host genes was observed, including those involved in protein translation, antigen presentation, and GTP-mediated signaling. The interactome analysis identified 73 host and pathogen gene pairs with correlated expression levels. We discovered significant correlations between transcripts of GAS genes involved in hyaluronic capsule production and host endocytic vesicle formation, GAS GTPases and host fibrinolytic genes, and GAS response to interaction with neutrophils. We also identified a strong signal, suggesting interaction between host γδ T cells and genes in the GAS mevalonic acid synthesis pathway responsible for production of isopentenyl-pyrophosphate, a short-chain phospholipid that stimulates these T cells. Taken together, our Q:2 results are unique in providing a comprehensive understanding of the hostâpathogen interactome during mucosal infection by a bacterial pathogen. Longitudinal pharyngeal infection of cynomolgus macaques by group A Streptococcus Briefly, animals were GAS-culture negative and had negligible antistreptolysin O titers, indicating no recent history of GAS exposure. Twenty animals were subjected to a mock-inoculation protocol (PBS only) for 5 weeks, rested for 4 weeks, and inoculated in the upper respiratory tract with 107 CFUsMGAS5005. Blood, saliva, and throat swabs were collected on days 0, 1, 2, 4, 7, 9, 16, 23, 32, 45, 58, 72, and 86. Only the first nine time-points were studied because specimens collected during days 0 to 32 had matching comparator specimens from the mock-infection protocol. Thirty-two clinical and laboratory parameters were measured by the same veterinarian during mock and infection periods. Array data was only for the tonsil swabs, while blood and saliva used for other tests.
2010-03-18 | E-GEOD-20262 | biostudies-arrayexpress
Project description:Streptococcus pyogenes or group A Streptococcus (GAS) is a leading cause of bacterial pharyngitis, skin and soft tissue infections, life-threatening invasive infections, and the post-infectious autoimmune syndromes of acute rheumatic fever and post-streptococcal glomerulonephritis. Genetic manipulation of this important pathogen is complicated by resistance of the organism to genetic transformation. Very low transformation efficiency is attributed to recognition and degradation of introduced foreign DNA by a type I restriction-modification system encoded by the hsdRSM locus. DNA sequence analysis of this locus in ten GAS strains that had been previously transformed with an unrelated plasmid revealed that six of the ten harbored a spontaneous mutation in hsdR, S, or M. The mutations were all different, and at least five of the six were predicted to result in loss of function of the respective hsd gene product. The unexpected occurrence of such mutations in previously transformed isolates suggested that the process of transformation selects for spontaneous inactivating mutations in the Hsd system. We investigated the possibility of exploiting the increased transformability of hsd mutants by constructing a deletion mutation in hsdM in GAS strain 854, a clinical isolate representative of the globally dominant M1T1 clonal group. Mutant strain 854hsdM exhibited a 5-fold increase in transformation efficiency compared to the wild type parent strain and no obvious change in growth or off-target gene expression. We conclude that genetic transformation of GAS selects for spontaneous mutants in the hsdRSM restriction modification system. We propose that use of a defined hsdM mutant as a parent strain for genetic manipulation of GAS will enhance transformation efficiency and reduce the likelihood of selecting spontaneous hsd mutants with uncharacterized genotypes.
2021-04-14 | GSE167217 | GEO
Project description:Streptococcus pyogenes (Group A Streptococcus: GAS) is a major human pathogen that causes streptococcal pharyngitis, skin and soft-tissue infections, and life-threatening conditions such as streptococcal toxic shock syndrome (STSS). A large number of virulence-related genes are encoded on GAS genomes, which are involved in host-pathogen interaction, colonization, immune invasion, and long-term survival within hosts, causing the diverse symptoms. Here, we investigated the interaction between GAS-derived extracellular vesicles and host cells in order to reveal pathogenicity mechanisms induced by GAS infection.
2021-05-17 | PXD026040 | JPOST Repository
Project description:Streptococcus pyogenes (Group A Streptococcus; GAS) commonly causes pharyngitis in children and adults, with severe invasive disease and immune sequelae being an infrequent consequence. The ability of GAS to invade the host and establish infection likely involves subversion of host immune defenses. However, the signaling pathways and innate immune responses of epithelial cells to GAS are not well understood. In this study, we utilized RNAseq to characterize the inflammatory responses of primary human tonsil epithelial (TEpi) cells to infection with the laboratory-adapted M6 strain JRS4 and the M1T1 clinical isolate 5448. Both strains induced the expression of genes encoding a wide range of inflammatory mediators, including IL-8. Pathway analysis revealed differentially expressed genes between mock and JRS4 or 5448-infected TEpi cells, were enriched in transcription factor networks that regulate IL-8 expression, such as AP-1, ATF-2 and NFAT. While JRS4 infection resulted in high levels of secreted IL-8, 5448 infection did not, suggesting that 5448 may post-transcriptionally dampen IL-8 production. Infection with 5448ΔcepA, an isogenic mutant lacking the IL-8 protease SpyCEP, resulted in IL-8 secretion levels comparable to JRS4 infection. Complementation of 5448ΔcepA and JRS4 with a plasmid encoding 5448-derived SpyCEP significantly reduced IL-8 secretion by TEpi cells. Our results suggest that intracellular infection with the pathogenic GAS M1T1 clone induces a strong pro-inflammatory response in primary tonsil epithelial cells, but modulates this host response by selectively degrading the neutrophil-recruiting chemokine IL-8 to benefit infection.
2018-05-08 | GSE107001 | GEO