Staphylococcus aureus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA151965 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:In this work we have demonstrated increased mutability of Staphylococcus aureus and S. epidermidis in biofilms and have explored the mechanisms underlying the enhanced mutability. A novel static biofilm model, utilising cellulose filter disks, was developed to support the formation of mature biofilms with sufficiently high cell densities to permit determination of mutation frequencies. The mutability of biofilm cultures increased up to 60 fold and 4 fold for S. aureus and S. epidermidis, respectively, compared with planktonic cultures. Incorporation of antioxidants into S. aureus biofilms reduced mutation frequencies, indicating that increased oxidative stress underlies increased mutability in the biofilm. Transcriptional profiling revealed upregulation of the superoxide dismutase gene, sodA, in early biofilm cultures, also suggesting enhanced oxidative stress in these cultures. However, loss of the genes encoding superoxide dismutases or peroxidases did not specifically exacerabate biofilm mutability. In S. aureus SH1000, hydrogen peroxide was found to contribute to biofilm mutability. Three growth conditions (18 hr planktonic growth, 48 hr biofilm growth and 144 biofilm growth) of which there are three biological replicates of each
2012-03-01 | E-GEOD-35837 | biostudies-arrayexpress
Project description:In this work we have demonstrated increased mutability of Staphylococcus aureus and S. epidermidis in biofilms and have explored the mechanisms underlying the enhanced mutability. A novel static biofilm model, utilising cellulose filter disks, was developed to support the formation of mature biofilms with sufficiently high cell densities to permit determination of mutation frequencies. The mutability of biofilm cultures increased up to 60 fold and 4 fold for S. aureus and S. epidermidis, respectively, compared with planktonic cultures. Incorporation of antioxidants into S. aureus biofilms reduced mutation frequencies, indicating that increased oxidative stress underlies increased mutability in the biofilm. Transcriptional profiling revealed upregulation of the superoxide dismutase gene, sodA, in early biofilm cultures, also suggesting enhanced oxidative stress in these cultures. However, loss of the genes encoding superoxide dismutases or peroxidases did not specifically exacerabate biofilm mutability. In S. aureus SH1000, hydrogen peroxide was found to contribute to biofilm mutability.
2012-03-01 | GSE35837 | GEO
Project description:Squalene makes up 12 % of human skin surface lipids, however little is known about its affects on the host skin microbiome. Here we tested the effect of squalene on genetic regulation of staphylococci, showing that it profoundly affects expression virulence or colonisation determinants, and of iron uptake systems.
2018-06-30 | E-MTAB-6352 | biostudies-arrayexpress
Project description:Staphylococci are major pathogens in humans and animals and emerging antibiotic-resistant strains have further increased the importance of this health issue. The existence of a genetic basis of host response to bacterial infections has been widely documented but the underlying mechanisms and genes are still largely unknown. Previously, two divergent lines of sheep selected on their milk somatic cell count called high and low SCS lines, have been showed to be respectively more and less susceptible to intra mammary infections (IMI). Transcriptional profiling of milk somatic cells (MSC) of high and low SCS sheep infected successively by S. epidermidis and S. aureus was performed to provide enhanced knowledge about the genetic basis of differential host response to IMI with Staphylococci. Gene expression in MSC of high and low SCS sheep collected 12h post-challenge was performed on a 15K gene ovine oligoarray (Agilent). MSC were mainly neutrophils. The high number of differentially expressed genes between the two bacterial strains indicated, among others, increased number of T-cells in MSC after S. aureus, compared to S. epidermidis challenge. Differential regulation of 366 genes between resistant and susceptible animals was largely associated with immune and inflammatory response (including pathogen recognition TLR2 pathway and cell migration), signal transduction, cell proliferation and apoptosis. Close biological connection between most of differentially expressed genes into Ingenuity Pathway Analysis networks further indicated consistency between the genes that were differentially-expressed between resistant and susceptible animals. Gene profiling in high and low SCS sheep provided strong candidates for biological pathway and gene underlying genetically determined resistance and susceptibility towards Staphylococci infections opening new fields for further investigation. Keywords: Staphylococcus epidermidis, Staphylococcus aureus, milk somatic cells, mammalian, transcriptome, immunity, mastitis 22 samples in a two-colour dye-swap experimental design
2011-09-30 | E-GEOD-24925 | biostudies-arrayexpress
Project description:Is there a universal genetically programmed defense providing tolerance to antibiotics when bacteria grow as biofilms? A comparison between biofilms of three different bacterial species by transcriptomic and metabolomic approaches uncovered no evidence of one. Single-species biofilms of three bacterial species (Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii) were grown in vitro for three days then challenged with respective antibiotics (ciprofloxacin, daptomycin, tigecycline) for an additional 24 h. All three microorganisms displayed reduced susceptibility in biofilms compared to planktonic cultures. Global transcriptomic profiling of gene expression comparing biofilm to planktonic and antibiotic-treated biofilm to untreated biofilm was performed. Extracellular metabolites including 18 amino acids, glucose, lactate, acetate, formate, and ethanol were measured to characterize the utilization of carbon sources between biofilms, treated biofilms, and planktonic cells. While all three bacteria exhibited a species-specific signature of stationary phase, no conserved gene, gene set, or common functional pathway could be identified that changed consistently across the three microorganisms. Across the three species, glucose consumption was increased in biofilms compared to planktonic cells and alanine and aspartic acid utilization were decreased in biofilms compared to planktonic cells. The reasons for these changes were not readily apparent in the transcriptomes. No common shift in the utilization pattern of carbon sources was discerned when comparing untreated to antibiotic-exposed biofilms. Overall, our measurements do not support the existence of a common genetic or biochemical basis for biofilm tolerance against antibiotics. Rather, there are likely myriad genes, proteins, and metabolic pathways that influence the physiological state of microorganisms in biofilms contributing to antibiotic tolerance. The Staphylococcus aureus microarray data from the study described above is deposited here.
2021-10-18 | GSE185864 | GEO
Project description:Staphylococci are major pathogens in humans and animals and emerging antibiotic-resistant strains have further increased the importance of this health issue. The existence of a genetic basis of host response to bacterial infections has been widely documented but the underlying mechanisms and genes are still largely unknown. Previously, two divergent lines of sheep selected on their milk somatic cell count called high and low SCS lines, have been showed to be respectively more and less susceptible to intra mammary infections (IMI). Transcriptional profiling of milk somatic cells (MSC) of high and low SCS sheep infected successively by S. epidermidis and S. aureus was performed to provide enhanced knowledge about the genetic basis of differential host response to IMI with Staphylococci. Gene expression in MSC of high and low SCS sheep collected 12h post-challenge was performed on a 15K gene ovine oligoarray (Agilent). MSC were mainly neutrophils. The high number of differentially expressed genes between the two bacterial strains indicated, among others, increased number of T-cells in MSC after S. aureus, compared to S. epidermidis challenge. Differential regulation of 366 genes between resistant and susceptible animals was largely associated with immune and inflammatory response (including pathogen recognition TLR2 pathway and cell migration), signal transduction, cell proliferation and apoptosis. Close biological connection between most of differentially expressed genes into Ingenuity Pathway Analysis networks further indicated consistency between the genes that were differentially-expressed between resistant and susceptible animals. Gene profiling in high and low SCS sheep provided strong candidates for biological pathway and gene underlying genetically determined resistance and susceptibility towards Staphylococci infections opening new fields for further investigation. Keywords: Staphylococcus epidermidis, Staphylococcus aureus, milk somatic cells, mammalian, transcriptome, immunity, mastitis
2011-10-01 | GSE24925 | GEO
Project description:Staphylococcus aureus is one of the earliest pathogens that persists the airways of cystic fibrosis (CF) patients and contributes to increased inflammation and decreased lung function. In contrast to other staphylococci, S. aureus possesses two superoxide dismutases (SODs), SodA and SodM, with SodM being unique to S. aureus. Both SODs arm S. aureus for its fight against oxidative stress, a byproduct of inflammatory reactions. Despite complex investigations it is still unclear, if both enzymes are crucial for the special pathogenicity of S. aureus. To investigate the role of both SODs during staphylococcal persistence in CF airways, we analyzed survival and gene expression of S. aureus CF isolates and laboratory strains in different CF-related in vitro and ex vivo settings. Bacteria located in inflammatory and oxidized CF sputum transcribed high levels of sodA and sodM. Especially expression values of sodM were remarkably higher in CF sputum than in bacterial in vitro cultures. Interestingly, also S. aureus located in airway epithelial cells expressed elevated transcript numbers of both SODs, indicating that S. aureus is exposed to oxidative stress at various sites within CF airways. Both enzymes promoted survival of S. aureus during PMN killing and seem to act compensatory, thereby giving evidence that the interwoven interaction of SodA and SodM contributes to S. aureus virulence and facilitates S. aureus persistence within CF airways
2020-01-27 | GSE131862 | GEO
Project description:We examined the differential gene expression of Staphylococcus epidermidis and Staphylococcus epidermidis in dual species biofilms. Therefore, we performed RNA-Seq on single and dual species biofilms and we compared the gene expression levels in dual species biofilms to those in single species biofilms.
2016-05-27 | GSE79575 | GEO
Project description:Interactions between human keratinocytes and secreted factors from Staphylococcus aureus biofilm were investigated using microarray analysis. Relative to control cells, biofilm-secreted factors upregulated cytokine and chemokine genes in keratinocytes. Genes associated with DNA damage and oxidative stress were also induced in keratinocytes treated with secreted factors from S. aureus. Here we show that secreted factors from S. aureus biofilm cultures differentially impact several aspects of wound healing processes. Human keratinocytes were grown in co-culture with mature S. aureus biofilms for 24 hours. Keratinocytes exposed to S. aureus biofilm were analyzed in quadruplicate. Control cells were also analyzed in quadruplicate. Dye-swaps were performed.
2011-08-30 | E-GEOD-24370 | biostudies-arrayexpress
Project description:<p>Staphylococcus aureus asymptomatically colonizes the nasal cavity and pharynx of up to 60% of the human population and, as an opportunistic pathogen, can breach its normal habitat, resulting in life-threatening infections. S. aureus infections are of additional concern for populations with impaired immune function such as those with cystic fibrosis (CF) or chronic granulomatous disease. Multi-drug resistance is increasingly common in S. aureus infections, creating an urgent need for new antimicrobials or compounds that improve efficacy of currently available antibiotics. S. aureus biofilms, such as those found in the lungs of people with CF and in soft tissue infections, are notoriously recalcitrant to antimicrobial treatment due to the characteristic metabolic differences associated with a sessile mode of growth. In this work, we show that another CF pathogen, Burkholderia cenocepacia, produces one or more secreted compounds that can prevent S. aureus biofilm formation and inhibit existing S. aureus biofilms. The B. cenocepacia-mediated antagonistic activity is restricted to S. aureus species and perhaps some other staphylococci; however, this inhibition does not necessarily extend to other Gram-positive species. This inhibitory activity is due to death of S. aureus through a contact-independent mechanism, potentially mediated through the siderophore pyochelin and perhaps additional compounds. This works paves the way to better understanding of interactions between these two bacterial pathogens.</p>
2024-11-26 | MTBLS11049 | MetaboLights