Biofilm formation by Staphylococcus aureus on stainless steel surfaces and evaluation of its sensitivity to sanitizers

This study aimed to assess the ability of adhesion, detachment, and biofilm formation of the reference strain Staphylococcus aureus CCM 4223 on a stainless steel surface, and the efficacy of three disinfectants: preparation A (based on peracetic acid, 20 mg/l), preparation B (newly developed disinfectant with a combination of two active ingredients, caprylic acid and hydrogen peroxide, 25 mg/l), and preparation C (based on sodium hypochlorite, 200 mg/l) in removing S. aureus cells adhered onto this surface. Cell detachment was around 5 log CFU/cm 2 (colony forming units) over the first 6 h and around 6 log CFU/cm 2 over 48 h characterizing a high persistence of cells on the tested surface. The number of cells (5–7 log CFU/cm 2 ) needed for biofilm formation was noted already after 6 h of incubation. The decrease in cell counts caused by preparation A was 1.12–2.07 log CFU/cm 2 ( P < 0.0001), whereas for preparation C and preparation B, the decrease was 1.13–2.08 log CFU/cm 2 and 1.61–2.16 log CFU/cm 2 , respectively ( P < 0.0001). Preparation A was found to be the most effective (80.9%) in reducing the adhered cell count in the biofilm matrix. From these results, the assayed S. aureus strain revealed high capacities to adhere and form biofilms on stainless steel surfaces, and the cells in biofilm matrixes were resistant to total removal when exposed to the evaluated disinfectants.