Plasmid Curing in Antibiotic- Resistant Escherichia coli Isolated from Herbal Cosmetic Powders

Abstract

Antibiotic resistance, largely driven by plasmid-mediated genes, is a growing public-health threat, yet the presence of resistant bacteria in herbal cosmetic powders remains underexplored, creating a critical research gap in the safety of widely used natural products. This study aimed to isolate Escherichia coli from commonly used herbal cosmetic powders and evaluate the effectiveness of plasmid curing using sodium dodecyl sulfate (SDS) and heat-shock treatment. E. coli strains were isolated from Multani Mitti, Avaram Poo, Rose Powder, and Kasturi Manjal, confirmed through standard biochemical and Gram-staining techniques, and assessed for antibiotic resistance. Resistant isolates were subjected to plasmid curing, and plasmid loss was analyzed by alkaline lysis and agarose gel electrophoresis, followed by post-curing antibiotic susceptibility testing. The key findings revealed that several isolates carried plasmids associated with resistance, and SDS- and heat-shock-based curing resulted in partial or complete loss of plasmids, restoring antibiotic sensitivity in treated strains. These results demonstrate that herbal cosmetic powders can serve as overlooked reservoirs of plasmid-mediated antibiotic-resistant E. coli, and effective plasmid curing highlights the direct link between plasmid presence and drug resistance. The study emphasizes the need for stricter microbial quality control in herbal cosmetic manufacturing and provides baseline evidence that can guide regulatory policies and future antimicrobial resistance research.

Introduction

Bacteria are ubiquitous, adaptable microorganisms that play essential roles in human health and ecosystems, although some species, such as Escherichia coli, can cause disease. A key factor behind bacterial adaptability is the presence of plasmids—self-replicating DNA elements that often carry genes for antibiotic resistance and can spread rapidly between bacteria through horizontal gene transfer. This plasmid-mediated resistance poses a serious global health concern, including risks associated with contaminated consumer products such as herbal cosmetic powders.

This study investigated bacterial contamination, antibiotic resistance, and plasmid involvement in four herbal cosmetic powders: Multani Mitti, Aavaram Powder, Rose Powder, and Kasturi Manjal. Bacterial isolation revealed significant growth in Multani Mitti and Rose Powder samples. Gram staining and biochemical tests confirmed the presence of Gram-negative E. coli in Rose Powder. Pre-curing antibiotic sensitivity tests showed resistance or intermediate resistance to tetracycline, amoxicillin, and kanamycin, indicating multidrug resistance.

Plasmid curing was performed using two methods—SDS treatment and heat shock—to assess the role of plasmids in antibiotic resistance. Post-curing antibiotic tests demonstrated increased sensitivity to kanamycin but persistent resistance to tetracycline and amoxicillin. Agarose gel electrophoresis confirmed effective plasmid removal, with SDS achieving complete curing (100%) and heat shock achieving approximately 95% curing. While SDS was more effective, heat treatment was identified as a safer, more practical approach for cosmetic products.

Overall, the findings highlight that herbal cosmetic powders can harbor multidrug-resistant E. coli, largely driven by plasmid-mediated resistance. The study underscores the importance of strict quality control, routine microbial monitoring, and safe plasmid-reduction strategies to ensure consumer safety and limit the spread of antibiotic resistance through cosmetic and environmental routes.

Conclusion

In this study, Escherichia coli was successfully isolated from selected herbal cosmetic powders, and its antibiotic resistance was determined to be plasmid-mediated. Plasmid curing experiments revealed that SDS was more effective than heat shock in eliminating plasmids, confirming the role of plasmids in carrying resistance traits. Phytochemical screening of Rose Powder and Multani Mitti showed the presence of valuable flavonoids, indicating their potential antioxidant and therapeutic properties. The detection of antibiotic-resistant bacteria highlights the importance of strict hygiene and quality control during the preparation and handling of herbal cosmetics. Simultaneously, the presence of bioactive compounds underscores the medicinal potential of these powders. Overall, this study demonstrates the dual nature of herbal cosmetic powders: while they may harbor plasmid-mediated antibiotic-resistant bacteria, they also contain beneficial phytochemicals. The findings emphasize the need for integrated approaches that ensure consumer safety while preserving the natural therapeutic value of herbal products.

References

[1] Alqahtani, M. H., Bhat, M. J., Badawi, A. S., Asiri, G. B., Alhmare, A. M., Rashid, A., Altalhiyyah, K. S., & Alwimny, A. A. (2023). Awareness and knowledge of antibiotic resistance and risks of self-medication with antibiotics among the Aseer region population, Saudi Arabia. Cureus, 15(6), e40762. [2] Anderson, J., Smith, L., & Brown, P. (2023). Mechanisms of plasmid-mediated antibiotic resistance in bacteria. Journal of Antimicrobial Chemotherapy, 78(4), 890–902. [3] Dahal, R. (2024). Indole test procedure and interpretation for bacterial isolates. Journal of Microbial Methods, 15(4), 145–150. [4] Dewan, R., & Uecker, R. (2023). Plasmids and their role in bacterial adaptation and antibiotic resistance. Microbial Genetics, 15(2), 101–118. [5] Fursova, T. (2022). Plasmid curing and its applications in controlling antibiotic resistance in bacteria. Journal of Microbial Methods, 190, 106–115. [6] Kumar, A., Sharma, S., & Verma, R. (2022). Flavonoids: A treasure house of prospective bioactive compounds in herbal formulations. Journal of Medicinal Plants Research, 16(7), 123–135. [7] Letchumanan, V., Chan, K. G., & Lee, L. H. (2015). Plasmid curing as a tool to study antibiotic resistance in bacteria. Frontiers in Microbiology, 6, 118. [8] Li, X., Zhang, Y., & Wang, S. (2021). Plasmid curing of antibiotic-resistant Escherichia coli isolates from herbal cosmetic products by sodium dodecyl sulfate and heat shock methods. Journal of Applied Microbiology, 131(6), 2048–2057. [9] Panthee, B., Gyawali, S., Panthee, P., & Techato, K. (2022). Environmental and human microbiome for health. Life, 12(3), 456. [10] Rahman, M. M., Islam, M. A., & Hossain, M. A. (2021). Plasmid curing of Escherichia coli isolated from herbal cosmetic products by SDS and heat shock method. Journal of Applied Microbiology, 131(5), 1789–1798. [11] Roy, S., Kumar, A., & Singh, P. (2023). Microbial quality and multidrug resistance in commercially available herbal cosmetic powders. International Journal of Cosmetic Science, 45(2), 101–115. [12] Sharma, A., Patwardhan, R. B., Dhakephalkar, P. K., Chopade, B. A., Dhavale, D. D., & Bhonde, R. R. (2018). Purification and characterization of an active principle, lawsone, responsible for the plasmid curing activity of Plumbago zeylanica root extracts. 3 Biotech, 8, 473. [13] Shintani, M., Sanchez, Z. K., & Kimbara, K. (2015). Genomics of microbial plasmids: Classification, replication, and ecological significance. Frontiers in Microbiology, 6, 242. [14] Singh, M. K. (2010). Plasmid DNA transformation in Escherichia coli: effect of heat shock temperature, duration, and cold incubation of CaCl?-treated cells. Journal of Microbiological Methods, 82(3), 243–248. [15] Sultana, S., Lawag, I. L., Lim, L. Y., Foster, K. J., & Locher, C. (2024). A critical exploration of the total flavonoid content assay for honey. Methods and Protocols, 7(6), 95. [16] Ward, M., O’Neill, C., & O’Connor, M. (2020). Plasmid-mediated antibiotic resistance in Escherichia coli isolated from herbal medicinal products. Journal of Applied Microbiology, 129(5), 1234–1245.

Copyright

Copyright © 2026 V Harini, P Vijayalakshmi, D Sumalatha . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.