Preventing Bacterial Infections: One Plant Extract at a Time


More than 80% of bacterial infections are caused by the formation of biofilms in the body (Sharma et al., 2019). These infections are becoming increasingly more difficult to treat or eradicate because of bacteria’s growing antibiotic resistance to current treatments. Biofilm formation is mediated by quorum sensing, a mechanism of bacterial communication. A new approach for combating biofilm formation, which could be a source for supplementary therapy through vitamins and minerals, targets the steps involved in quorum sensing. One way to inhibit biofilm formation is through the use of plant extracts and naturally occurring peptides (Ghosh et al., 2021). Specifically, our research was aimed at combating canine periodontal disease which is caused by both Gram-negative and Gram-positive bacteria. Current approaches for treating this disease include adding thymoquinone, a seed extract, and nisin, a lantibiotic, to various bacterial strains. In this study, we proposed to research the effects of these naturally derived compounds on the biofilm formation of a model bacterial system called Vibrio harveyi. We hoped to understand the inhibiting mechanisms of these compounds and to uncover any synergistic effects when they are added together. We measured bacterial growth, bioluminescence and biofilm formation of Vibrio Harveyi in the presence of various concentrations of thymoquinone and nisin.



Brackman, G., & Coenye, T. (2015). Quorum sensing inhibitors as anti-biofilm agents. Current pharmaceutical design, 21(1), 5-11.

Breukink, E., & de Kruijff, B. (2006). Lipid II as a target for antibiotics. Nature reviews Drug discovery, 5(4), 321-323. From

Cegelski, L., Marshall, G. R., Eldridge, G. R., & Hultgren, S. J. (2008). The biology and future prospects of antivirulence therapies. Nature reviews. Microbiology, 6(1), 17–27. From

Chaieb, K., Kouidhi, B., Jrah, H. et al. Antibacterial activity of Thymoquinone, an active principle of Nigella sativa and its potency to prevent bacterial biofilm formation. BMC Complement Altern Med 11, 29 (2011). From

Costa, O. Y., Raaijmakers, J. M., & Kuramae, E. E. (2018). Microbial extracellular polymeric

substances: ecological function and impact on soil aggregation. Frontiers in microbiology, 9, 1636. From

Cunha, E., Rebelo, S., Carneiro, C. et al. A polymicrobial biofilm model for testing the antimicrobial potential of a nisin-biogel for canine periodontal disease control. BMC Vet Res 16, 469 (2020). From

Cunha E, Freitas FB, São Braz B, Moreira da Silva J, Tavares L, Veiga AS, Oliveira M. Polyphasic Validation of a Nisin-Biogel to Control Canine Periodontal Disease. Antibiotics. 2020; 9(4):180. From

Defoirdt, T. (2018). Quorum-sensing systems as targets for antivirulence therapy. Trends in Microbiology, 26(4), 313-328. From

Dogs, D. D. in, Lorraine Hiscox DVM FAVD Dip. AVDC; Jan Bellows, & Contributors: Lorraine Hiscox DVM FAVD Dip. AVDC; Jan Bellows. (n.d.). Dental disease in dogs. vca_corporate. Retrieved November 30, 2021, from

Field, D., Siesling, N., Cotter, P. D., Ross, R. P., & Hill, C. (2016). Synergistic nisin-polymyxin combinations for the control of pseudomonas biofilm formation. Frontiers in Microbiology, 7.

Ghosh, A. K., Panda, S. K., & Luyten, W. (2021). Anti-vibrio and immune-enhancing activity of medicinal plants in shrimp: A comprehensive review. Fish & Shellfish Immunology.

Guo, D., Yang, Z., Zheng, X., Kang, S., Yang, Z., Xu, Y., ... & Xia, X. (2019). Thymoquinone inhibits biofilm formation and attachment-invasion in host cells of Vibrio parahaemolyticus. Foodborne pathogens and disease, 16(10), 671-678. From

Mekhemar M, Hassan Y, Dörfer C. Nigella sativa and Thymoquinone: A Natural Blessing for Periodontal Therapy. Antioxidants. 2020; 9(12):1260. From

Mok, K. C., Wingreen, N. S., & Bassler, B. L. (2003). Vibrio harveyi quorum sensing: a coincidence detector for two autoinducers controls gene expression. The EMBO journal, 22(4), 870–881. From

Nackerdien, Z. E., Keynan, A., Bassler, B. L., Lederberg, J., & Thaler, D. S. (2008). Quorum sensing influences Vibrio harveyi growth rates in a manner not fully accounted for by the marker effect of bioluminescence. Plos one, 3(2), e1671. From

Niemiec, B. A. (2008). Periodontal disease. Topics in companion animal medicine, 23(2), 72-80. From

Paluch, E., Rewak-Soroczyńska, J., Jędrusik, I., Mazurkiewicz, E., & Jermakow, K. (2020).

Prevention of biofilm formation by quorum quenching. Applied Microbiology and Biotechnology, 104(5), 1871-1881. From

​​Richardson, J., Keefe, E., & Bourjaily, M. (n.d.). Periodontal disease in dogs. Small Door Veterinary. Retrieved December 8, 2021, from

Reuter K, Steinbach A, Helms V (2016) Interfering with bacterial quorum sensing. Perspect Medicin Chem 8:1–15, From

Sharma, D., Misba, L., & Khan, A. U. (2019). Antibiotics versus biofilm: an emerging battleground in microbial communities. Antimicrobial Resistance & Infection Control, 8(1), 1-10. From

Tantivitayakul, P., Kaypetch, R., & Muadchiengka, T. (2020). Thymoquinone inhibits biofilm formation and virulence properties of periodontal bacteria. Archives of oral biology, 115, 104744. From

Vikram, A., Jayaprakasha, G.K., Jesudhasan, P.R., Pillai, S.D., & Patil, B.S. (2010). Suppression of bacterial cell-cell signaling, biofilm formation and type III secretion system by citrus flavonoids. Journal of applied microbiology, 109(2), 515-527.

Vlamakis, H. (2011). The world of biofilms.

Vollmer, W. (2015). Peptidoglycan. In Molecular Medical Microbiology (pp. 105-124). Academic Press. From

Wallis, C., & Holcombe, L. J. (2020, September 21). A review of the frequency and impact of periodontal disease in dogs. Wiley Online Library. Retrieved December 10, 2021, from

Waters, C., & Bassler, B. (2005). QUORUM SENSING: Cell-to-Cell Communication in Bacteria. Annual Review Of Cell And Developmental Biology, 21(1), 319-346.

Zhang, L., Liang, E., Cheng, Y., Mahmood, T., Ge, F., Zhou, K., ... & Tan, Y. (2020). Is combined medication with natural medicine a promising therapy for bacterial biofilm infection?. Biomedicine & Pharmacotherapy, 128, 110184. From

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Copyright (c) 2022 Carolyn Awad, Maya Ismail, Riley Peterson