Starvation Survival and Biofilm Formation under Subminimum Inhibitory Concentration of QAMs.

Abstract

Quaternary ammonium methacrylates (QAMs) are useful antimicrobial compounds against oral bacteria. Here, we investigated the effects of two QAMs, dimethylaminododecyl methacrylate (DMADDM) and dimethylaminohexadecyl methacrylate (DMAHDM), on biofilm formation, survival and development of tolerance by biofilm, and survival and development of tolerance against QAMs after prolonged starvation. Enterococcus faecalis (E. faecalis), Streptococcus gordonii (S. gordonii), Lactobacillus acidophilus (L. acidophilus), and Actinomyces naeslundii (A. naeslundii) were used. Minimum inhibitory concentration (MIC) of QAMs against multispecies biofilm was determined. Biofilm formed under sub-MIC was observed by crystal violet staining and confocal laser scanning microscopy (CLSM). Metabolic activity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactic acid production measurement. Development of tolerance was determined by MIC values before and after exposure to QAMs or after prolonged starvation. It was found that E. faecalis and S. gordonii could survive and form biofilm under sub-MIC of QAMs. Lactic acid production from biofilms formed under sub-MIC was significantly higher than control specimens (p < 0.05). The exposure to sub-MIC of QAMs promoted biofilm formation, and prolonged starvation or prolonged contact with sub-MIC helped bacteria develop tolerance against killing by QAMs.

• Authors: Sanjay Kumar Tiwari, Suping Wang, Yannan Huang, Xuedong Zhou, Hockin H K Xu, Biao Ren, Xian Peng, Yan Xiao, Mingyun Li, Lei Cheng
• Journal: BioMed research international (Biomed Res Int) Vol. 2021 Pg. 8461245 ( 2021) ISSN: 2314-6141 [Electronic] United States
• PMID: 33511211 (Publication Type: Journal Article)
• Copyright: Copyright © 2021 Sanjay Kumar Tiwari et al.

Chemical References

• Anti-Bacterial Agents
• Methacrylates
• Methylamines
• Quaternary Ammonium Compounds
• dimethylaminododecyl methacrylate
• dimethylaminohexadecyl methacrylate
• Lactic Acid

Topics

• Anti-Bacterial Agents (pharmacology)
• Bacterial Infections (microbiology)
• Biofilms (drug effects)
• Dental Pulp Cavity (microbiology)
• Dental Pulp Diseases (microbiology)
• Drug Resistance, Bacterial (drug effects)
• Enterococcus faecalis (drug effects, genetics)
• Humans
• Lactic Acid (metabolism)
• Lactobacillus acidophilus (drug effects, genetics)
• Methacrylates (pharmacology)
• Methylamines
• Microbial Sensitivity Tests
• Quaternary Ammonium Compounds (pharmacology)
• Streptococcus gordonii (drug effects, genetics)