Antibiotic resistance linked to these household products

The study, by the research team of assistant professor Hui Peng in the department of chemistry in the School of Arts and Sciences, was able to show that triclosan – a chemical often included in household items such as hand soaps, toothpaste and cleaning products to fight bacteria — is the dominant antibiotic in Ontario sewage sludge.

The findings were published in the journal Environmental Science & Technology.

“Since there are so many different antibiotics in sewage sludge, we were surprised to find that the majority of the sludge’s antibacterial activity could be directly linked to triclosan alone,” says Holly Barrett, Ph.D. candidate in the Peng group and lead author on the study.

The research was conducted by investigating sewage sludge from Ontario’s sewage treatment plants (STPs). As the study notes, STPs are a breeding ground for antibiotic-resistant bacteria because of the diverse set of antibiotics found there. This is because after we flush our household products down the drain, the antibiotic ingredients in those products are carried to STP where they accumulate.

Among thousands of chemicals coexisting in the sludge, triclosan was found to be the dominant antibacterial compound affecting E. coli.

Barrett notes in the study that antibiotic resistance is a growing concern. Antibiotic-resistant bacteria – also commonly known as “superbugs” – are strains of bacteria that are not killed by antibiotics. They are produced when continuous exposure to antibiotics forces the bacteria to evolve several generations to survive the antibiotics. These bacteria can be very dangerous to humans, especially those with weakened immune systems. Between 2014 and 2016, there were 700,000 deaths worldwide attributed to antibiotic resistance.

In 2016, the US Food and Drug Administration banned the use of triclosan in antibacterial liquid soaps, and then a year later its use in topical antiseptics found in healthcare settings. Currently, there are limited regulations for triclosan in Canada, and Health Canada considers triclosan safe for use in a variety of consumer products at specified levels.

“I think our results show that there is an urgent need for regulatory agencies in Canada to re-evaluate the use of triclosan,” says Barrett.

“It’s still used in thousands of different household and cosmetic products in Canada, as well as in healthcare settings. While there are some regulations to limit the maximum amount of triclosan allowed in consumer products, even very low levels of the chemical can cause bacteria to grow resistant to antibiotics over time.

“More action needs to be taken.”