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. There are not many effective antiseptics and disinfectants to solve this problem. Quaternary ammonium salts are currently one of the promising classes of disinfectants but their use is limited by the ability of microorganisms to develop resistance to these compounds. Modification of QAS with substituents of various natures is a possible way to solve this problem. Aims: in this work a bactericidal activity comparative analysis for two original quaternary ammonium compounds based on pyridoxine was carried out in comparison with benzalkonium chloride. Materials and methods: the bactericidal activity of 0.1% and 0.2% aqueous solutions of original QACs based on pyridoxine were studied against two widespread pathogens: S. aureus and E. coli. Antibacterial activity data were obtained using a standard in vitro test (bactericidal activity test on a metal surface, exposure time 1, 5 and 15 minutes). In addition to standard conditions, antibacterial efficacy was also studied under protein loading conditions (adding BSA solution to the surface). Results: for the studied compounds the RF (reduction factor - reduction lgCFU of microorganisms) was on average ≥ 3. Complicating the model conditions in the form of protein load led to a decrease in efficiency by 1-3 orders. We have also observed an interesting effect of exposure time-dependent specificity reversal to the S. aureus and E. coli. Conclusions: The obtained results showed high activity of the studied compounds (corresponding to the effectiveness criterion RF≥3 for commercial compounds used in this field).