Evaluation of the neutralizing properties of sodium thiosulfate concerning potassium peroxomonosulfate in microbiolgical studies

Hospital-acquired infections in veterinary clinics are a significant problem, as they contribute to the spread of antibiotic-resistant bacterial strains and increase the risks to animal and human health. Disinfectants based on potassium peroxomonosulfate, which is a powerful oxidizing agent, are widely used in veterinary facilities to control microbial contamination. The study evaluated the effectiveness of neutralizing solutions based on sodium thiosulfate for inactivating potassium peroxomonosulfate residues and their effect on bacterial viability. Three solutions were tested: sodium thiosulfate with mass concentrations of 30% and 2% and a standard neutralizer with polysorbate 80 and lecithin. The evaluation was performed by the method of serial dilutions with the counting of colony-forming units, and the results were analyzed using ANOVA and Tukey’s test. The highest neutralization efficiency was shown by a sodium thiosulfate solution with a mass concentration of 30%. The number of bacteria after the addition of neutralized solution of Etasept decreased by 0.22 lg CFU/cm3 compared with the control suspension diluted with saline. Both neutralizing solutions (2% Na2S2O3 and standard neutralizing solution), which contain a solution of sodium thiosulfate solution with a mass concentration of 2% led to a decrease in the number of live bacteria in comparison with the control The use of a neutralizer contributed to a decrease in the bacterial load for E. coli by 0.79 lg (6.1 times) and for K. pneumonia by 0.75 lg (5.6 times) compared to control samples. At the same time, no difference in the neutralizing properties of both solutions was found (p = 0.999). The use of 30% and 2% sodium thiosulfate solutions did not affect the viability of bacteria (p = 0.938), as the level of CFU/cm3 remained at the level of the control positive samples. The results obtained indicate that normal sodium thiosulfate solution can be used as an alternative neutralizer for the determination of residual concentrations of potassium peroxomonosulfate. Its effectiveness in the study was not inferior to the standard neutralizing solution, which allows us to consider sodium thiosulfate as an affordable and easy-to-use option for veterinary clinics. An additional advantage is its wide availability and the possibility of its preparation without the use of specialized components. Further studies should cover a wider range of microorganisms, including resistant strains, and evaluate the effect of the neutralizer exposure time. In addition, it is necessary to take into account real clinical conditions, where the concentrations of residual disinfectants can vary, which affects the accuracy of microbiolgical analyzes. Key words: sodium thiosulfate, neutralizing solutions, oxidative disinfectants, microbiolgical analysis, hospital-acquired infections, disinfection control, sampling.