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Updated: Jun 19, 2025
Nanomechanics of Drug-target Interactions and Antibacterial Resistance Detection
Published on: October 25, 2013
Totarol exhibits antibacterial effects through antibiofilm and combined interaction against vancomycin-resistant
Ga-Eun Hyeon1, Yong-Bin Eom1,2
1Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, Asan, Chungnam, 31538, Republic of Korea.
Abstract:
The rise of vancomycin-resistant enterococci (VRE) due to antibiotic overuse poses a significant threat to long-term care patients and those with impaired immune systems. Therefore, it is imperative to seek alternatives to overcome multidrug resistance. This study aimed to evaluate totarol, a natural compound derived from Podocarpus totara, for its antibacterial activity against vancomycin-resistant Enterococcus faecalis (VREF). Totarol exhibited potent antibacterial activity at a very low concentration of 0.25 µg/mL and demonstrated antibiofilm effects through biofilm inhibitory concentration and biofilm eradication concentration assays. Confocal laser scanning microscopy confirmed that totarol inhibited not only biofilm mass but also bacterial cell viability. The combinatorial use of sublethal concentrations of totarol and vancomycin showed antibacterial activity, as observed in the time-kill assay. Quantitative polymerase chain reaction assays revealed a concentration-dependent downregulation of key virulence genes (vanA, ace, asa, efaA, and esp) in VREF when exposed to totarol. In summary, totarol emerges as a promising adjuvant with vancomycin for inhibiting VREF, addressing vancomycin resistance and biofilm formation-critical challenges associated with VRE infection. Since this was an in vitro study, the role of totarol in the clinical implications of VREF treatment remains to be demonstrated.
Insights
Totarol, a natural compound, shows potent antibacterial and antibiofilm activity against vancomycin-resistant Enterococcus faecalis (VREF). It also downregulates key virulence genes, suggesting potential as an adjuvant therapy for VREF infections.
Area of Science:
- Microbiology
- Natural Product Chemistry
- Infectious Diseases
Background:
- Antibiotic overuse has led to the rise of vancomycin-resistant enterococci (VRE), a significant threat to vulnerable patient populations.
- Multidrug resistance necessitates the exploration of alternative therapeutic strategies against VRE.
- Vancomycin-resistant Enterococcus faecalis (VREF) poses a critical challenge in healthcare settings.
Purpose of the Study:
- To evaluate the antibacterial and antibiofilm efficacy of totarol, a compound from Podocarpus totara, against VREF.
- To investigate the effect of totarol on VREF virulence gene expression.
- To assess the potential of totarol as an adjuvant therapy in combination with vancomycin.
Main Methods:
- Determination of minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) for totarol against VREF.
- Confocal laser scanning microscopy (CLSM) to visualize totarol's effect on biofilm formation and bacterial viability.
- Time-kill assays to evaluate the synergistic effect of totarol and vancomycin.
- Quantitative polymerase chain reaction (qPCR) to analyze the expression of VREF virulence genes (vanA, ace, asa, efaA, esp).
Main Results:
- Totarol demonstrated potent antibacterial activity against VREF at a low concentration (0.25 µg/mL).
- Totarol effectively inhibited and eradicated VREF biofilms, reducing biofilm mass and bacterial viability.
- Combinatorial treatment with sublethal totarol and vancomycin exhibited enhanced antibacterial effects.
- Totarol exposure led to a concentration-dependent downregulation of key VREF virulence genes.
Conclusions:
- Totarol exhibits significant antibacterial and antibiofilm properties against VREF.
- Totarol shows promise as an adjuvant therapy, potentially enhancing vancomycin efficacy and combating VREF.
- Further in vitro studies are warranted to explore the clinical implications of totarol in VREF treatment.
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