FIGURE 4.

Effects of pseudo synovial fluid (pSynF) on methicillin-susceptible Staphylococcus aureus (MSSA). (A) Comparison of MSSA aggregates in human synovial fluid (SynF) vs. pSynF using SEM. Magnification: scale bar = 15 μm. (B) Fibrinogen (Fg) (left) and albumin (Alb) (right) content of pSynF and pSynF aggregates compared to aggregates formed in synovial fluid by Western blotting. (C) Graphs showing CFU/ml in Trypticase Soy Broth (TSB) and pSynF before trypsin dispersion vs. CFU/ml after trypsin dispersion [(“after Tryp” in subsequent graphs) n = 12 for each condition]. (D) Effects of amikacin (AMK) on fluids containing protein/proteoglycan concentrations found in pSynF. Controls are TSB alone and complete pSynF (n = 8–9 for each condition). All components were dissolved in TSB. (E) Dose response of MSSA to AMK in TSB vs. synovial fluid (left; n = 9/condition) and of TSB vs. pSynF (right; n = 12/condition). (F) Viscosity of pSynF compared to that of synovial fluid and H₂O using a ball velocity method (n = 10/condition). Values graphed are means ± SD. Viscosity is expressed as centiPoise (cP). In panels (A–F), *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001.