| 1. |
- Firdaus, Rininta, et al.
(författare)
-
sodA and gap genes as markers for the identification of staphylococcus capitis
- 2019
-
Ingår i: Indonesian Biomedical Journal. - 2085-3297 .- 2355-9179. ; 11, s. 314-319
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Rapid and accurate identification of Staphylococcus capitis is required to provide a better prognosis for endocarditis patients and tackle the emergence of multidrug resistant strains of the bacteria in hospitals. The current study was aimed to develop polymerase chain reaction (PCR) assay for specific identification of S. capitis using sodA and gap genes as markers. METHODS: Five sequences of sodA and sixteen sequences of gap registered in GeneBank were analysed using bioinformatic tools. PCR primers were designed based on the conserved and specific regions of sodA and gap. Four clinical isolates of S. capitis (named no. 56-59) and six reference strains of coagulase-negative staphylococci (CoNS) species including S. epidermidis ATCC 35984, S. epidermidis 48951I/09, S. lugdunensis 44987/09, S. sciuri 109645I/08, S. warneri 135612/09, S. hominis 114202/08 were used to validate the conventional PCR system. RESULTS: The current PCR system only amplified the DNA template of S. capitis. Current primers specifically targeted S. capitis as the agarose images only showed bands from S. capitis samples. CONCLUSION: The sodA and gap genes might serve as effective markers for identification of S. capitis using conventional PCR. The PCR assay in the current study was able to identify five clinical isolates of S. capitis accurately without mispriming, misamplification and misidentification.
|
|
| 2. |
|
|
| 3. |
- Gerner, Erik, 1986, et al.
(författare)
-
Targeting Pseudomonas aeruginosa quorum sensing with sodium salicylate modulates immune responses in vitro and in vivo.
- 2023
-
Ingår i: Frontiers in cellular and infection microbiology. - 2235-2988. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- Chronic infections are a major clinical challenge in hard-to-heal wounds and implanted devices. Pseudomonas aeruginosa is a common causative pathogen that produces numerous virulence factors. Due to the increasing problem of antibiotic resistance, new alternative treatment strategies are needed. Quorum sensing (QS) is a bacterial communication system that regulates virulence and dampens inflammation, promoting bacterial survival. QS inhibition is a potent strategy to reduce bacterial virulence and alleviate the negative impact on host immune response.This study investigates how secreted factors from P. aeruginosa PAO1, cultured in the presence or absence of the QS inhibitor sodium salicylate (NaSa), influence host immune response.In vitro, THP-1 macrophages and neutrophil-like HL-60 cells were used. In vivo, discs of titanium were implanted in a subcutaneous rat model with local administration of P. aeruginosa culture supernatants. The host immune response to virulence factors contained in culture supernatants (+/-NaSa) was characterized through cell viability, migration, phagocytosis, gene expression, cytokine secretion, and histology.In vitro, P. aeruginosa supernatants from NaSa-containing cultures significantly increased THP-1 phagocytosis and HL-60 cell migration compared with untreated supernatants (-NaSa). Stimulation with NaSa-treated supernatants in vivo resulted in: (i) significantly increased immune cell infiltration and cell attachment to titanium discs; (ii) increased gene expression of IL-8, IL-10, ARG1, and iNOS, and (iii) increased GRO-α protein secretion and decreased IL-1β, IL-6, and IL-1α secretion, as compared with untreated supernatants.In conclusion, treating P. aeruginosa with NaSa reduces the production of virulence factors and modulates major immune events, such as promoting phagocytosis and cell migration, and decreasing the secretion of several pro-inflammatory cytokines.
|
|
| 4. |
- Trobos, Margarita, 1980, et al.
(författare)
-
Genomics of Staphylococcus aureus and Staphylococcus epidermidis from Periprosthetic Joint Infections and Correlation to Clinical Outcome
- 2022
-
Ingår i: Microbiology Spectrum. - : American Society for Microbiology. - 2165-0497. ; 10:4
-
Tidskriftsartikel (refereegranskat)abstract
- The approach of sequencing or genotyping to characterize the pathogenic potential of staphylococci from orthopedic device-related infection (ODRI) has been applied in recent studies. These studies described the genomic carriage of virulence in clinical strains and compared it with those in commensal strains. Only a few studies have directly correlated genomic profiles to patient outcome and phenotypic virulence properties in periprosthetic joint infections (PJIs). We investigated the association between genomic variations and virulence-associated phenotypes (biofilm-forming ability and antimicrobial resistance) in 111 staphylococcal strains isolated from patients with PJI and the infection outcome (resolved/unresolved). The presence of a strong biofilm phenotype in Staphylococcus aureus and an antibiotic-resistant phenotype in Staphylococcus epidermidis were both associated with treatment failure of PJI. In S. epidermidis, multidrug resistance (MDR) and resistance to rifampicin were associated with unresolved infection. Sequence type 45 (ST45) and ST2 were particularly enriched in S. aureus and S. epidermidis, respectively. S. epidermidis ST2 caused the majority of relapses and was associated with MDR and strong biofilm production, whereas ST215 correlated with MDR and non/weak biofilm production. S. aureus agr II correlated with resolved infection, while S. epidermidis agr I was associated with strong biofilm production and agr III with non/weak production. Collectively, our results highlight the importance of careful genomic and phenotypic characterization to anticipate the probability of the strain causing treatment failure in PJI. Due to the high rate of resistant S. epidermidis strains identified, this study provides evidence that the current recommended treatment of rifampicin and a fluoroquinolone should not be administered without knowledge of the resistance pattern.
|
|
| 5. |
- Turner, Adam Benedict, et al.
(författare)
-
Role of sodium salicylate in Staphylococcus aureus quorum sensing, virulence, biofilm formation and antimicrobial susceptibility
- 2022
-
Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- The widespread threat of antibiotic resistance requires new treatment options. Disrupting bacterial communication, quorum sensing (QS), has the potential to reduce pathogenesis by decreasing bacterial virulence. The aim of this study was to investigate the influence of sodium salicylate (NaSa) on Staphylococcus aureus QS, virulence production and biofilm formation. In S. aureus ATCC 25923 (agr III), with or without serum, NaSa (10 mM) downregulated the agr QS system and decreased the secretion levels of alpha-hemolysin, staphopain A and delta-hemolysin. Inhibition of agr expression caused a downregulation of delta-hemolysin, decreasing biofilm dispersal and increasing biofilm formation on polystyrene and titanium under static conditions. In contrast, NaSa did not increase biofilm biomass under flow but caused one log10 reduction in biofilm viability on polystyrene pegs, resulting in biofilms being twice as susceptible to rifampicin. A concentration-dependent effect of NaSa was further observed, where high concentrations (10 mM) decreased agr expression, while low concentrations (≤0.1 mM) increased agr expression. In S. aureus 8325-4 (agr I), a high concentration of NaSa (10 mM) decreased hla expression, and a low concentration of NaSa (≤1 mM) increased rnaIII and hla expression. The activity of NaSa on biofilm formation was dependent on agr type and material surface. Eight clinical strains isolated from prosthetic joint infection (PJI) or wound infection belonging to each of the four agr types were evaluated. The four PJI S. aureus strains did not change their biofilm phenotype with NaSa on the clinically relevant titanium surface. Half of the wound strains (agr III and IV) did not change the biofilm phenotype in the 3D collagen wound model. In addition, compared to the control, ATCC 25923 biofilms formed with 10 mM NaSa in the collagen model were more susceptible to silver. It is concluded that NaSa can inhibit QS in S. aureus, decreasing the levels of toxin production with certain modulation of biofilm formation. The effect on biofilm formation was dependent on the strain and material surface. It is suggested that the observed NaSa inhibition of bacterial communication is a potential alternative or adjuvant to traditional antibiotics.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Vassey, Matthew, et al.
(författare)
-
G1 Cell Cycle Arrest Is Induced by the Fourth Extracellular Loop of Meningococcal PorA in Epithelial and Endothelial Cells
- 2023
-
Ingår i: Cellular Microbiology. - 1462-5814 .- 1462-5822. ; 2023
-
Tidskriftsartikel (refereegranskat)abstract
- Neisseria meningitidis is the most frequent cause of bacterial meningitis and is one of the few bacterial pathogens that can breach the blood-brain barrier (BBB). The 37/67 kDa laminin receptor (LamR) was previously identified as a receptor mediating meningococcal binding to rodent and human brain microvascular endothelial cells, which form part of the BBB. The meningococcal surface proteins PorA and PilQ were identified as ligands for this receptor. Subsequently, the fourth extracellular loop of PorA (PorA-Loop4) was identified as the LamR-binding moiety. Here, we show that PorA-Loop4 targets the 37 kDa laminin receptor precursor (37LRP) on the cell surface by demonstrating that deletion of this loop abrogates the recruitment of 37LRP under meningococcal colonies. Using a circularized peptide corresponding to PorA-Loop4, as well as defined meningococcal mutants, we demonstrate that host cell interaction with PorA-Loop4 results in perturbation of p-CDK4 and Cyclin D1. These changes in cell cycle control proteins are coincident with cellular responses including inhibition of cell migration and a G1 cell cycle arrest. Modulation of the cell cycle of host cells is likely to contribute to the pathogenesis of meningococcal disease.
|
|
| 9. |
- Zaborowska, Magdalena, 1984, et al.
(författare)
-
Immunomodulatory effects exerted by extracellular vesicles from Staphylococcus epidermidis and Staphylococcus aureus isolated from bone-anchored prostheses
- 2021
-
Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612. ; 278
-
Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus aureus and Staphylococcus epidermidis are the bacteria that most frequently cause osteomyelitis. This study aimed to determine whether staphylococci isolated from osteomyelitis associated with septic loosening of orthopedic prostheses release extracellular vesicles (EVs) and, if so, to determine tentative immunomodulatory effects on the human monocytic cell line THP-1. EVs were isolated from bacterial cultures using filtration and ultracentrifugation and characterized by scanning electron microscopy, nanoparticle tracking analysis and Western Blot. The cytotoxic effect of EVs was analyzed by Nucleo Counter and lactate dehydrogenase (LDH) analyses. Confocal laser scanning microscopy was employed to visualize the uptake of EVs by THP-1 cells. Activation of the transcription factor nuclear factor-kappa B (NF-kappa B) was determined in THP1-Blue T NF-kappa B cells, and the gene expression and secretion of cytokines were determined by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. All investigated strains, irrespective of their biofilm formation ability, were able to secrete EVs in vitro. The S. aureus strains produced significantly more EVs than the S. epidermidis strains. Both S. aureus-derived EVs and S. epidermidis-derived EVs were internalized by THP-1 cells, upregulated Toll-like receptor 3 (TLR3) gene expression, activated NF-kappa B, and promoted the gene expression and secretion of interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1, matrix metallopeptidase (MMP)-9 and IL-10. Whereas EVs from both staphylococcal species upregulated the proapoptotic DNA damage-inducible transcript 4 (DDIT4) gene and downregulated the antiapoptotic B-cell lymphoma 2 (Bcl-2) gene, cytolysis was preferentially induced in S. aureus EV-stimulated cells, possibly related to the expression of cytolytic proteins predominantly in S. aureus EVs. In conclusion, staphylococcal EVs possess potent cytolytic and immunomodulatory properties.
|
|
