In vitro study of the bactericidal activity for new derivatives of quaternary ammonium salts based on pyridoxine against gram-positive / gram-negative bacteria

BACKGROUND: Preventive care and successful treatment of infectious diseases (including hospital-acquired infections) are among the most important tasks of modern healthcare. Not many effective antiseptics and disinfectants available can solve this problem. Quaternary ammonium salts are currently one of the promising classes of disinfectants; however, their use is limited by the ability of microorganisms to develop resistance to the compounds. Modification of quaternary ammonium salts with substituents of various profiles is a possible way to solve this problem.

AIM: To conduct a comparative analysis of the bactericidal activity of two original quaternary ammonium compounds based on pyridoxine in comparison with benzalkonium chloride.

MATERIALS AND METHODS: The bactericidal profiles of 0.1 and 0.2% aqueous solutions of original quaternary ammonium salts based on pyridoxine were studied against two widespread pathogens: Staphylococcus aureus and Escherichia coli. Antibacterial activity data were obtained using a standard in vitro test (bactericidal activity test on a metal surface; exposure time of 1, 5, and 15 min). In addition to standard conditions, antibacterial efficacy was studied under protein loading conditions, in which BSA solution was added to the surface.

RESULTS: For the studied compounds, the reduction factor (RF, reduction lgCFU of microorganisms) was on average ≥3. Protein loading led to a decrease in efficiency by 1–3 times. An interesting effect of exposure time-dependent specificity reversal to the S. aureus and E. coli was observed.

CONCLUSIONS: The results showed the high activity of the studied compounds, which corresponds to the effectiveness criterion of RF ≥3 for commercial compounds used in this field.