Introduction: The assessment of the sporicidal effectiveness of disinfectants is important from the point of view of the prevention of nosocomial infections and spore contamination of clinical samples, medical equipment and materials used in patient care. The rods of Bacillus spp. cause infections of the digestive system, bloodstream and, less often, respiratory tract. Cases were diagnosed in immunocompromised patients, malignant neoplasms and in neonatal wards. The source of the infection was hospital linen, reusable towels, catheters or milk from the human milk bank.
Aim of the study: Determination of the minimal sporicidal parameters of a disinfectant containing peracetic acid.
Material and methods: The sporicidal activity of a disinfectant containing peracetic acid against Bacillus subtilis and Bacillus cereus spore suspensions was tested in a defined concentration range during a contact time of 15 minutes, in the presence of various interfering substances (clean and dirty conditions) according to the European Standard PN-EN 17126: 2019-01.
Results: The disinfecting preparation containing peracetic acid showed sporicidal activity against Bacillus subtilis at a concentration of 1% for 15 minutes under clean and dirty conditions and at concentrations of 0.5%, 1.00% and 1.25% against the Bacillus cereus spores during the same contact time but only under dirty conditions. The preparation showed no sporicidal activity against Bacillus cereus at concentrations of 2%, 3%, 4% and 5% during a contact time of 15 minutes under both dirty and clean conditions.
Conclusions: In areas where there is a risk of infecting a patient or contaminating clinical specimens, materials and equipment with spores of Bacillus spp., it is necessary to use disinfectants with sporicidal activity confirmed according to the PN-EN 17126: 2019-01 standard. The sporicidal activity of disinfectants containing peracetic acid may depend on the method of preparing the solutions, their concentration, pH, temperature and the contamination degree of the disinfected surface.
Keywords: Bacillus cereus; Bacillus subtilis; disinfectants; peracetic acid; spores.
© National Institute of Public Health NIH – National Research Institute.