Surreal illustration of toothpaste spreading antibiotic resistance.

Is Your Toothpaste Spreading Superbugs? The Hidden Dangers of Triclosan

Nico Varela in Health & Wellness August 2025 • 4 min read.

"New research reveals how triclosan, a common ingredient in personal care products, promotes antibiotic resistance and what you can do to protect yourself."

Antibiotic resistance is a growing global crisis, threatening to reverse decades of medical progress. While the overuse of antibiotics is a well-known culprit, emerging research suggests that other, more subtle factors may also be at play. One such factor is the widespread use of non-antibiotic antimicrobials (NAAMs), chemicals designed to kill or inhibit the growth of microorganisms, in everyday products.

Triclosan (TCS) is one of the most common NAAMs. For years, it has been added to a vast array of consumer goods, including toothpaste, soaps, cosmetics, and even plastics, to prevent bacterial contamination. Its ubiquity means that TCS is now a common environmental contaminant, found in rivers, lakes, and even our own bodies. But what if this seemingly harmless ingredient is silently contributing to the rise of antibiotic-resistant bacteria, or "superbugs"?

A groundbreaking study published in Environment International sheds light on this very concern. Researchers investigated whether TCS, at concentrations typically found in the environment, can promote the horizontal transfer of antibiotic resistance genes between bacteria. This process, known as horizontal gene transfer (HGT), allows bacteria to share genetic material, including the genes that make them resistant to antibiotics, and could accelerate the evolution and spread of superbugs.

Triclosan: A Silent Driver of Antibiotic Resistance?

Surreal illustration of toothpaste spreading antibiotic resistance.

The researchers focused on the ability of triclosan to facilitate the transfer of antibiotic resistance genes (ARGs) between bacteria through a process called conjugation. This is essentially bacterial sex, where genetic material, including resistance genes, are passed from one bacterium to another.

The study used Escherichia coli (E. coli) and Pseudomonas putida bacteria in controlled experiments. They exposed these bacteria to varying concentrations of TCS, mimicking environmental levels. The findings were alarming:

Increased Gene Transfer: Even at low, environmentally relevant concentrations, TCS significantly increased the rate at which antibiotic resistance genes were transferred between bacteria.
ROS Production: TCS exposure led to the generation of reactive oxygen species (ROS), highly reactive molecules that can damage DNA and cell structures.
Membrane Damage: TCS compromised bacterial cell membranes, making them more permeable and potentially facilitating the entry or exit of genetic material.
SOS Response: TCS triggered the SOS response, a bacterial repair mechanism that can inadvertently increase the rate of genetic mutation and horizontal gene transfer.
Enhanced Energy: TCS exposure also boosted ATP production (cellular energy) which supported the energy demanding processes of HGT.

These results suggest that TCS doesn't just kill bacteria; it actively promotes the spread of antibiotic resistance by creating a stressful environment that encourages gene transfer. This is especially concerning given the widespread presence of TCS in our environment and daily lives.

Protecting Yourself and Combating Antibiotic Resistance

While the study highlights the risks associated with TCS, it's important to remember that you're not powerless. By making informed choices about the products you use and supporting policies that limit the use of harmful chemicals, you can help protect yourself and slow the spread of antibiotic resistance.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.envint.2018.10.040, Alternate LINK

Title: Triclosan At Environmentally Relevant Concentrations Promotes Horizontal Transfer Of Multidrug Resistance Genes Within And Across Bacterial Genera

Subject: General Environmental Science

Journal: Environment International

Publisher: Elsevier BV

Authors: Ji Lu, Yue Wang, Jie Li, Likai Mao, Son Hoang Nguyen, Tania Duarte, Lachlan Coin, Philip Bond, Zhiguo Yuan, Jianhua Guo

Published: 2018-12-01

Everything You Need To Know

What is triclosan and how does it contribute to antibiotic resistance?

Triclosan (TCS) is an antimicrobial agent added to many consumer products like toothpaste and soaps. Research indicates that TCS can promote antibiotic resistance by facilitating the transfer of antibiotic resistance genes between bacteria through a process called conjugation. It does this by increasing gene transfer, producing reactive oxygen species (ROS), damaging cell membranes, triggering the SOS response, and enhancing ATP production.

What is horizontal gene transfer and why is it important in the context of antibiotic resistance?

Horizontal gene transfer (HGT) is the process by which bacteria share genetic material, including genes that make them resistant to antibiotics. This process is accelerated by the presence of triclosan (TCS). The phenomenon is concerning because it leads to the rapid evolution and spread of superbugs, making infections harder to treat. HGT is especially concerning because it can occur between different species of bacteria.

What were the key findings of the study regarding triclosan's effects on bacteria?

The study revealed that even at low, environmentally relevant concentrations, triclosan (TCS) significantly increased the rate at which antibiotic resistance genes were transferred between bacteria. Additionally, TCS exposure led to the generation of reactive oxygen species (ROS), compromised bacterial cell membranes, triggered the SOS response, and boosted ATP production which supported the energy demanding processes of HGT. These effects collectively promote the spread of antibiotic resistance.

How does the SOS response relate to the spread of antibiotic resistance when bacteria are exposed to triclosan?

The SOS response is a bacterial repair mechanism activated by DNA damage. In the context of triclosan (TCS) exposure, the SOS response can inadvertently increase the rate of genetic mutation and horizontal gene transfer (HGT). This means that while the bacteria are trying to repair themselves, they are also becoming more prone to acquiring and spreading antibiotic resistance genes. Thus the SOS response contributes to the acceleration of superbug development.

What are reactive oxygen species and what role do they play in the development of antibiotic resistance with triclosan exposure?

Reactive oxygen species (ROS) are highly reactive molecules that can damage DNA and cell structures. Triclosan (TCS) exposure leads to the generation of ROS in bacteria. While ROS can contribute to the antimicrobial effects of TCS, they also induce stress responses in bacteria, such as the SOS response, which can inadvertently increase the rate of genetic mutation and horizontal gene transfer (HGT), facilitating the spread of antibiotic resistance. The dual nature of ROS highlights the complex ways in which TCS influences bacterial behavior.