N-chlorosuccinimide enhancing the antimicrobial effect of benzalkonium chloride on biofilm Pseudomonas aeruginosa and its interaction mechanisms

Abstract

This study investigated the influence of N-chlorosuccinimide (NCS) pretreatment on the antimicrobial effect of benzalkonium chloride (BZC, representative of QACs) against biofilm bacteria and its mechanisms. Results show that 0.04 − 0.07 mmol/L NCS pretreatment significantly increased the antimicrobial efficacy of 0.03 mmol/L BZC on biofilm cells by 30% − 70%. The main mechanisms involved membrane permeability, oxidative damage, and metabolic disorder. More precisely, NCS pretreatment increased the permeability of bacteria and reduced the activity of the electron transport system (ETS) and dehydrogenase (DHA). At the same time, the oxidative damage of both endogenous and exogenous ROS and the disorder of the antioxidant enzymes (superoxide dismutase and catalase) further improved their combined antibacterial ability. Moreover, NCS pretreatment greatly reduced the resistance of biofilm Pseudomonas aeruginosa to BZC. The findings of the study provide a new method to effectively enhance the antimicrobial efficiency of quaternary ammonium cationic surfactants (e.g., BZC) and reduce bacterial resistance, as well as a scientific guidance for the development of new antimicrobial products.

Keywords:

• Quaternary ammonium cationic surfactants
• ecotoxicology
• cytotoxicity
• antimicrobial agents

Author contribution

Zaihui Huang: Experiment, Writing-original draft, Data curation, Investigation, Methodology; Zheng Qi: Investigation, Methodology, Formal analysis; Xiaohu Ding: Investigation, Methodology; Chunguang Liu: experiment design, data analysis, and writing.

Competing interests

The authors have no competing interests to declare that are relevant to the content of this article.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Ethical approval and consent

All the authors agreed to submit and publish the paper and stated that this study did not involve ethical issues.

Additional information

Funding

This study has been supported by National Natural Science Foundation of China (42077391), Shandong Provincial Natural Science Foundation, China (ZR2019BB049). We would like to thank Zhifeng Li and Jingyao Qu from State Key laboratory of Microbial Technology of Shandong University for help and guidance in test analysis.