This study addresses the presence and frequency of particular genetic variants and virulence factors found in staphylococcal bacteria causing periprosthetic joint infection (PJI) of the hip and knee to ascertain their clinical relevance as predictors of treatment failure. We characterized the genetic virulence traits of a large collection of clinical staphylococci isolated from patients with PJI and evaluated their association with the patient’s infection outcome.

No 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.

Objectives: This study would like to investigate the in vitro antioxidant activity through 2,2-diphenyl-1-picrylhydrazyl assay and in vitro xanthine oxidase activity of the bulbs. This study performs in vivo assays to study the antihyperuricemic activity and antioxidant in the hyperuricemic rat through plasma malondialdehyde measurement. Method: The study was conducted by testing the fresh bulbs of bawang tiwai (Eleutherine palmifolia (L.) Merr. with chemical solvent of ethanol 70% to extract the bulbs. Allopurinol and Vitamin C were used as positive control for the antihyperuricemic assay and antioxidant assay, respectively. Other chemical substances were also used in this study. This study used chicken extract (Brands) 20 ml/kg/body weight to induce the level of uric acid in the blood serum, and potassium oxonate (Sigma 156124) to inhibit the uricase in rats. Results: The results show that the levels of uric acid were measured using spectrophotometer with dichloro-hydroxybenzen sulfonate (Biolabo) a as reagent. The ethanol extract of bawang tiwai (EBT) (E. palmifolia (L.) Merr) was potential to reduce uric acid level at 140, 280, and 560 mg/kg body weight, but possibly without inhibition against xanthine oxydase activity. Conclusion: All doses of EBT could inhibit lipid peroxidation in hyperuricemic condition caused by high purine diet in 14 days.

Objectives: This study would like to investigate the in vitro antioxidant activity through 2,2-diphenyl-1-picrylhydrazyl assay and in vitro xanthine oxidase activity of the bulbs. This study performs in vivo assays to study the antihyperuricemic activity and antioxidant in the hyperuricemic rat through plasma malondialdehyde measurement. Method: The study was conducted by testing the fresh bulbs of bawang tiwai (Eleutherine palmifolia (L.) Merr. with chemical solvent of ethanol 70% to extract the bulbs. Allopurinol and Vitamin C were used as positive control for the antihyperuricemic assay and antioxidant assay, respectively. Other chemical substances were also used in this study. This study used chicken extract (Brands) 20 ml/kg/body weight to induce the level of uric acid in the blood serum, and potassium oxonate (Sigma 156124) to inhibit the uricase in rats. Results: The results show that the levels of uric acid were measured using spectrophotometer with dichloro-hydroxybenzen sulfonate (Biolabo) a as reagent. The ethanol extract of bawang tiwai (EBT) (E. palmifolia (L.) Merr) was potential to reduce uric acid level at 140, 280, and 560 mg/kg body weight, but possibly without inhibition against xanthine oxydase activity. Conclusion: All doses of EBT could inhibit lipid peroxidation in hyperuricemic condition caused by high purine diet in 14 days.