Jouan cr3i centrifuge

Target organisms: Clinical isolates of carbapenem-resistant E. coli (CREC) and methicillin-resistant Staphylococcus aureus (MRSA; EMRSA-15 variant B1). Preparation of bacteria: 10 µL of test bacteria was transferred with a loop to sterile nutrient broth (10 mL; Oxoid, UK), mixed thoroughly and incubated aerobically at 37 °C for ∼24 h (±4 h). Broth cultures were centrifuged at 3000 rpm (1500×g; Jouan CR3i centrifuge: Thermo, UK) for 10 min and the remaining pellet re-suspended in 10 mL of sterile distilled water (DW). During time-kill assays, the PAA antimicrobial agent was inactivated after the appropriate contact time by the addition of a neutralising solution [3% (w/v) Tween 80, 0.3% (w/v) Lecithin, 1.0% (w/v) Sodium thiosulfate, 1.5% (w/v) K₂HPO₄, KH₂PO₄ 0.05% (w/v), 1% (w/v) Poly-[sodium-4-styrenesulfonate], 0.1% (v/v) Triton® X100 (Sigma-Aldrich, UK) and prepared in phosphate-buffered saline (PBS) solution (Oxoid, UK)]. Neutralising solutions were sterilised by autoclaving (121 °C for 15 min) and refrigerated (2–8 °C) until required. All microbiology studies were conducted by the Environmental Research Laboratory, University College Hospital.

Clinical isolates of carbapenem-resistant E.coli (CREC), meticillin-resistant Staphylococcus aureus (MRSA; EMRSA-15 variant B1), an extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and a type-culture of Streptococcus pyogenes ATCC 19615 were tested.
Overnight culture of the test bacteria (10 μL) was transferred to sterile nutrient broth (10 mL; Oxoid, UK), mixed thoroughly and incubated aerobically at 37 °C for 18 h. Broth cultures were centrifuged at 3000 rpm (1500 × g; Jouan CR3i centrifuge: Thermo, UK) for 10 min and the remaining pellet re-suspended in 10 mL of 0.5% w/v Bovine Serum Albumin (BSA) (Sigma-Aldrich, UK), sterile horse blood (Oxoid, UK), or no soil (sterile distilled water).