Pathogen-pathogen interactions, a way to soothe virulence?
Ontology highlight
ABSTRACT:
ORGANISM(S): Klebsiella oxytoca Bacillus thuringiensis Staphylococcus aureus
PROVIDER: GSE145732 | GEO | 2020/02/22
REPOSITORIES: GEO
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Project description:The rise of multi-drug resistance in bacterial pathogens imposes the need to study these organisms from new angles. A little explored outset is to scrutinize bacterial niche adaptations and interactions among pathogenic and commensal bacteria, because they can provide a better understanding of the fitness of pathogens in their human host. We have previously shown that co-culturing of the pathogen Staphylococcus aureus with co-resident Klebsiella oxytoca or Bacillus thuringiensis wound isolates resulted in reduced levels of virulence factor secretion, suggesting that the presence of these co-resident bacteria would modulate S. aureus virulence. In the present study, we performed an in-depth investigation of changes in S. aureus gene expression upon co-cultivation with K. oxytoca and B. thuringiensis under infection-mimicking conditions. To this end, we profiled the cellular proteomes of the co-existing bacteria with special focus on S. aureus. In parallel, we employed RNA sequencing to highlight global changes in staphylococcal behaviour. The results imply that co-colonizing bacteria from chronic wounds can pacify S. aureus, and this conclusion was verified in a Galleria mellonella infection model. Altogether, our findings show that the presence of K. oxytoca and B. thuringiensis leads to massive rearrangements in S. aureus physiology and substantial reduction in virulence.
2020-04-22 | PXD017208 | Pride
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:Polymicrobial infections are intrinsically less susceptible to antimicrobial therapy, are more invasive and can induce enhanced inflammatory responses leading to negative clinical outcomes. The importance of studying the interaction between microbes themselves and their interactions with their host in combination has only been realised in recent years. However, there is a lack of simple, effective and low cost in vivo models to study these interactions with the host immune response. This study details the responses of Galleria mellonella larvae to disseminated combination infection by C. albicans and S. aureus and demonstrates the efficacy of antimicrobial chemotherapy on treating co-infected larvae. Doses of C. albicans (1 × 105 larva-1) and S. aureus (1 × 104 larva-1) which were non-lethal in mono-infection, when combined significantly lowered larval survival at (70 ± 3.33% [p < 0.01]), 48 (10 ± 3.33% [p < 0.0001]) and 72h (5 ± 6.66% [p < 0.0001]) h relative to larvae receiving S. aureus 2 × 104 larva-1 mono-infection. Co-infected larvae with S. aureus 2 × 104 larva-1 resulted in an increase in the density of circulating hemocytes relative to S. aureus mono-infected larvae. Co-infected larvae displayed a significantly higher overall S. aureus c.f.u larva-1 compared to larvae only infected with S. aureus. Co-infection resulted in dissemination throughout the host and the appearance of large nodules. Proteomic analysis of co-infected larval hemolymph revealed specific immune responses to bacterial and fungal infection by the increased abundance of a range of antimicrobial peptides, peptidoglycan, lipopolysaccharide and β-glucan recognition proteins and proteins associated with tissue invasion and nodule formation. The in vitro and in vivo efficacy of empirical antimicrobial drugs (amphotericin B & meropenem) was examined against C. albicans and S. aureus was also examined. meropenem was more effective than amphotericin B but a combination was most effective at improving survival of co-infected larvae. The effect of antimicrobial therapy on symptoms associated with co-infection was also assessed using Cryo-imaging. The processes of polymicrobial co-infection in G. mellonella are compared to those in mice models and larvae provide an easy to use and ethically acceptable in vivo system to assess polymicrobial interactions with their host.
2020-02-24 | PXD014273 | Pride
Project description:Interactions between human keratinocytes and secreted factors from Staphylococcus aureus biofilm and planktonic cultures were investigated using microarray analysis. Relative to planktonic secreted factors, biofilm secreted factors up regulated 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 biofilm. Here we show that secreted factors from S. aureus planktonic (PCM) and biofilm (BCM) cultures differentially impact several aspects of wound healing processes.
2011-08-31 | GSE24118 | GEO
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:Microorganisms form biofilms containing differentiated cell populations. To determine factors driving differentiation, we study protein distributions in bacterial biofilms using shotgun proteomics. Notably, zinc- and manganese-depleted portions of the biofilm repress the production of anti-staphylococcal molecules. Exposure to calprotectin (a host protein known to sequester metal ions at infectious foci) recapitulates responses occurring within metal-deplete portions of the biofilm and promotes interaction between P. aeruginosa and Staphylococcus aureus. Consistent with these results, the presence of calprotectin promotes co-colonization of the murine lung, and polymicrobial communities are found to co-exist in calprotectin-enriched airspaces of a cystic fibrosis lung explant. These findings, which demonstrate that metal fluctuations are a driving force of microbial community structure, have clinical implications because of the frequent occurrence of P. aeruginosa and S. aureus co-infections.
2016-06-22 | PXD004081 | Pride
Project description:The present work comprises the study of wound pathogenic bacteria as part of a community. It considers the interactions of two different S. aureus isolates with B. thuringiensis and K. oxytoca; all of them isolated from the same chronic wound of a patient with epidermolysis bullosa. Particular focus has been given on the interactions of S. aureus with other microbes due to its high prevalence among chronic wounds. During cultivation, no species performed as dominant or inhibited the growth of one another. Mass spectrometry was used to explore the inherent relationships between the staphylococcal strains and the coexisting bacteria exproteomes. The analysis showed an important reduction in the amount of staphylococcal cytoplasmic proteins when co-cultured with K. oxytoca and B. thuringiensis, this decrement did not occur with klebsiella and bacillus proteins. Interestingly, K. oxytoca and B. thuringiensis seemed to have a more evident response towards the presence of S. aureus in the culture, while the opposite was not observed with the staphylococcal isolates. Genomic analysis revealed isolate t13595 hypermutable characteristics, placing the interactions between staphylococcal isolates in the context of a chronic wound. Overall, the nature of the exoproteome variations among cultures suggests that adaptive mechanisms differ in all strains.
2018-10-17 | PXD005596 | Pride
Project description:Interactions between human keratinocytes and secreted factors from Staphylococcus aureus biofilm and planktonic cultures were investigated using microarray analysis. Relative to planktonic secreted factors, biofilm secreted factors up regulated 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 biofilm. Here we show that secreted factors from S. aureus planktonic (PCM) and biofilm (BCM) cultures differentially impact several aspects of wound healing processes. Secreted factors from S. aureus biofilm and planktonic cultures with equivalent population sizes were placed in contact with human foreskin keratinocytes for 4 hours. Keratinocytes were grown to ~90% confluency between passages 4-10.
2011-08-30 | E-GEOD-24118 | biostudies-arrayexpress
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.
2011-08-31 | GSE24370 | GEO
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