1 Introduction in vitro [3] [1,2] [3] 2 Method 2.1 General Incubator at 35 and 37 °C; pipettes of various sizes (Gilson); sterile tips, 100, 200, 500, and 1000 μL; 5 mL multichannel pipette (Fischer Supplies); centrifuge tubes (Fischer Supplies); vortex mixer (Fischer Supplies); centrifuge (Fisons); petridishes (Fischer Supplies); sterile universal bottles (Fischer Supplies); UV spectrophotometer (Shimadzu); sterile resazurin tablets (BDH Laboratory Supplies); sterile normal saline; sterile isosensitest broth (Oxoid); sterile isosensitest agar (Southern Group Laboratory, SGL); antibiotic solutions (Sigma–Aldrich); sterile solution of 10% (v/v) DMSO in water (Sigma–Aldrich). 2.2 Medium [4] [5] 2.3 Use of standardised bacterial colony numbers 5 2.4 Preparation of bacterial culture 6 2.5 Preparation of resazurin solution The resazurin solution was prepared by dissolving a 270 mg tablet in 40 mL of sterile distilled water. A vortex mixer was used to ensure that it was a well-dissolved and homogenous solution. 2.6 Preparation of the plates Fig. 1 6 5 Fig. 2 Fig. 1 3 Results [6] [6,7] Fig. 1 Table 1 Table 2 4 Concluding remarks [3]