Imagine a world where bacteria have become clever enough to resist even our most potent antibiotics. This will soon be the case, since multidrug-resistant (MDR) bacteria are becoming more resistant to alternative treatments. Therefore, an evaluation of potential phytobiotics is needed to find an alternative antimicrobial agent to reduce the over-reliance on antibiotics. Out of all the pathogens, the bacteria that is gaining more attention is Aeromonas hydrophila because of its ability to form a biofilm, which is a protective shield providing a shield that not only enhances its chances of survival but also increases its ability to resist antibiotics. Biofilms cause chronic infections and problems in industries like healthcare and food processing.
Recent research has focused on the use of essential oils as antimicrobials to counter the biofilm formation by these bacteria. This blog examines the effectiveness of Neroli oil against A. hydrophila. Using both laboratory and molecular docking experiments, we can examine bacterial virulence, biofilm formation, and understand their mode of action.
Bacteria and Their Biofilms
The gram-negative bacterium Aeromonas primarily inhabits aquatic habitats. It causes fin rot and fatal hemorrhagic septicemia in species like common carp, goldfish, and silver catfish, leading to huge economic loss. It mainly infects immunocompromised individuals, resulting in illnesses such as wound infections, gastroenteritis, and septicemia. What makes them a tough case to handle is their ability to form biofilms, which encase bacterial communities in an extracellular matrix produced by themselves.
Therefore, preventing these biofilms is essential to manage infections.
Essential Oils: Nature's Arsenal
Previously, there has been research done on the use of essential oils against bacterial growth, so the thought of using them against biofilm becomes interesting. In this study, we examined the potential of neroli essential oil to fight biofilms formed by A. hydrophila. To check the lowest concentration required of neroli oil to inhibit the biofilm formed by A. hydrophila, Minimum Inhibitory Concentration (MIC) test was conducted. Astoundingly, Neroli oil showed good efficacy even at lower concentrations, proving it to be a good candidate against biofilm formation. This strategic selection highlights not only potency but also its potential as a natural alternative to conventional antibiotics.
Research highlights the biofilm-disrupting and virulence inhibition potential of neroli essential oils against A. hydrophila. Key findings include:
- Biofilm formation & EPS reduction: Neroli oil caused the weakening of the biofilm structure in hydrophila by reducing EPS production and disrupting biofilm formation.
- Virulence factor inhibition: Proteases and elastases activity, which are essential for biofilm stability and tissue invasion, were decreased at sub-MIC concentration of neroli oil, limiting potential biofilm formation.
- Swarming motility inhibition: The swarming motility of bacteria was decreased when treated with neroli oil, which is an important factor in biofilm expansion as it helps bacteria to move to new suitable environments.
- Biofilm disruption: There was significant biofilm disruption observed at higher concentrations of neroli oil, which was confirmed by crystal violet staining and fluorescence.
Molecular Docking: Unlocking the Mechanisms Using in Silico Methods
To further understand how these essential oils function at the molecular level, in silico docking studies were conducted. The goal was to examine how the active components of neroli oil interact with key virulence proteins involved in biofilm formation.
The chemical compounds present in neroli oil showed the highest affinities with the fimbrial receptor (-5.6 kcal/mol, -4.4 kcal/mol, -5.1 kcal/mol) for Linalyl acetate, Linalool, and L-alpha terpineol; the highest affinities with VgrG2 (-4.5 kcal/mol) for Geranyl; and the highest affinities with FleQ (-5.3 kcal/mol). These docking results gave an insight into the molecular mechanism of antibacterial and antibiofilm properties of neroli essential oil. Docking studies verify that these oils target critical virulence proteins, providing a two-pronged approach to study infection control. This supports the biofilm inhibition found in the wet lab results.
Conclusion: A New Frontier in Biofilm Management
As we enter into an era where antibiotic resistance poses a growing concern, it is imperative that we explore plant-derived solutions like essential oils. The study conducted proved essential oil, especially neroli essential oil, a capable alternative to conventional antibiotics for treating biofilm-associated infections. Their extent to disrupt biofilm formation, inhibition of virulence factors, and interference with bacterial signaling emphasizes their potential as potent antimicrobial agents. Additional research, including in vivo studies and clinical trials, will be necessary to fully explore their potential in medical and food safety applications.
It's time to think creatively as antibiotic resistance is never-ending! In terms of managing biofilms, could essential oils be the next big thing? Though the journey is just getting started, the evidence is encouraging. A new era in disease management may be ushered by plant-based antimicrobials!
References
- Bakkali, F., Averbeck, S., Averbeck, D., & Idaomar, M. (2008). Biological effects of essential oils–a review. Food and Chemical Toxicology, 46(2), 446–475. https://doi.org/10.1016/j.fct.2007.09.106
- Mansuri, A., Lokhande, K., Kore, S., Gaikwad, S., Nawani, N., Swamy, K. V., & Pawar, S. (2022). Antioxidant, anti-quorum sensing, biofilm inhibitory activities and chemical composition of Patchouli essential oil: in vitro and in silico approach. Journal of Biomolecular Structure and Dynamics, 40(1), 154–165. https://doi.org/10.1080/07391102.2020.1810124
- Hatherell, S. K., Rees, P., Neubauer, M. P., Mastik, M., Lee, T., Edwards, A. M., Zand, K., & Walton, L. A. (2020). Leveraging machine learning to accelerate biofilm architecture analysis from confocal microscopy images. Scientific Reports. https://doi.org/10.1038/s41598-020-79128-x
- Lokhande, M. V., Raut, J. S., Mohan Karuppayil, S. (2023). The antimicrobial and antibiofilm potential of essential oils and their components against clinical and standard strains of bacteria. Journal of Applied Microbiology. https://doi.org/10.1016/j.compbiolchem.2023.107829
- Abdul Kari, Z., Wee, W., Mohamad Sukri, S. A., Che Harun, H., Hanif Reduan, M. F., Irwan Khoo, M., & Seong Wei, L. (2022). Role of phytobiotics in relieving the impacts of Aeromonas hydrophila infection on aquatic animals: a mini-review. Front Vet Sci, 9. https://doi.org/10.3389/fvets.2022.1023784
- Vijayakumar, S., Vaseeharan, B., Malaikozhundan, B., Gobi, N., Ravichandran, S., Karthi, S., & Sivakumar, N. (2017). A novel antimicrobial therapy for the control of Aeromonas hydrophila infection in aquaculture using marine polysaccharide coated gold nanoparticle. Microbial Pathogenesis, 110, 140–151. https://doi.org/10.1016/j.micpath.2017.06.029
Authors
Raj Mukund,¹ Reeya Jadhao,¹ Soham Chepurwar,¹ Ravali Amaraj,¹ Dr. Supriya Kore (supriya.kore@dpu.edu.in)²*
- Third Year B.Tech. Biotechnology Student
- Assistant Professor, Dr. D. Y. Patil Biotechnology and Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth, Pune