The U.S. Food and Drug Administration (FDA) banned 19 antiseptic chemicals from over-the-counter soaps, hand and body washes.

Citing concerns over long-term human safety and increased selection for antibiotic resistance, the FDA banned antiseptic chemicals on September 2, 2016. Antimicrobial washes also didn’t perform better than standard soap and water [1, 2]. Despite these findings and concerns, toothpaste, “First aid antiseptics”, antiseptic wipes, health care antiseptics, consumer antiseptic rubs, or antiseptics used by food industry CAN continue to use these 19 antiseptic chemicals [3-5]. Triclosan and triclocarban found in products including mouthwash, toothpaste, soaps, shoes, and toys, are two well-known antibiotics now banned from use in washes.

Triclosan Increased Antibiotic Resistance

The FDA ruling was an important milestone recognizing the importance of microbes for human health. The unnecessary use of antiseptics, especially antibiotics like triclosan, selects for bacteria that are resistant to the antibiotics. A recent review of the literature found that bacteria exposed to triclosan had increased resistance to triclosan, but also OTHER ANTIBIOTICS,

in this case chloramphenicol and tetracycline (Figure 1 and 2) [3]. The influence of triclosan on antibiotic resistance is especially important given how ubiquitous it is in our environment (Figure 2). Triclosan and related antibiotics have been used for over 40 years by hospitals and food service industry and in homes for about 25 years. These antibiotics are so widespread, that triclosan is found in human urine [6], blood, and breastmilk [7], sewage and natural waters [8, 9]. President Obama established a Task Force for Combating Antibiotic-Resistant Bacteria in 2014 due to the health issues antibiotic resistance raises.

Does Triclosan Change Microbiomes?

Microbiome community changes are a second, less recognized concern with using antiseptics. Triclosans were initially used due to their apparent low toxicity to humans [10-12] and our obsession of killing all “germs”. However, we know not all bacteria are “germs” needing to be killed. Niche filling, the idea that having non-pathogenic bacteria growing in places where pathogens can live keeps pathogens out, is a recurring finding in today’s microbiome research. Antimicrobials may be kicking out good tenants from our human “apartment building” body, allowing new, potentially disruptive tenants from moving in. As a human “landlord” I’m all about keeping good tenants who take care of my “apartment building” instead of throwing wild parties, knocking holes in the walls, and leaving trash around the building. So does triclosan kick out the good tenants?

Zebrafish studies have revealed shifts in the gut microbiome of adult fish exposed to triclosan. Similar results are seen with juvenile fathead minnows. Such microbiome population structural changes can be important. A human study correlated increased triclosan with increased body mass [6]. The authors suggested that the increased body mass may be due to microbiome changes. To date, there is one human microbiome study on triclosan’s effects on the mouth microbiome. Sixteen volunteers used toothpaste, liquid hand and dishwashing soap, and solid hand washing soap for 4 months, then non-triclosan containing products for 4 months. The study was a double blind, cross-over study, which is a very stringent experimental design. No significant changes were found in the microbiomes, though triclosan did increase in the subject’s urine during the study. The authors cite small sample size and background exposure to triclosans in the environment as potential issues of the study. All study subjects had triclosan levels in their urine before and after the study. Given the levels of triclosan in the environment, humans are most likely exposed to triclosan throughout development [15] and this continuous low-level exposure complicates microbiome studies [16].

Although safety was listed as a reason for banning these chemicals, data for triclosan’s influence on human health was the least supported by the literature.  Although triclosan induces tumor formation and mimics vertebrate hormones in non-human vertebrates, such as rodents and fish [13, 14], direct connections to human health are difficult to assess. Is this due to high background levels of these chemicals over the decades? Is this due to animal experiments being exposed to high levels or continuously to triclosan, while humans rinse triclosans off? It will be interesting to see if removing triclosan from home care product uses will decrease its presence in the environment and our bodies. Will changing our baseline level of triclosan make a difference in human health?

Next Steps? Additional Concerns About Banned Antiseptics

The FDA ban on these 19 antiseptic chemicals is an impressive step forward in removing antiseptics from common use. Our society’s germaphobia, or #bacteriahysteria as Elisabeth Bik at Microbiome Digest calls it, moved these products from commercial use and into home use. I’m glad to see that solid data and public pressure have removed 19 of these chemicals from home use. However, some concerns remain.

First, should we reconsider their use medical and food industry settings?

These antiseptics don’t improve hand-washing effectiveness in private homes. Do these antibiotics and antiseptics remove pathogens or select for resistant bacteria in industrial settings as they do in homes? Medical facilities and the food industry are key places for antibiotic resistance to spread quickly. Are these antiseptics helping or harming the rate and spread of antibiotic resistance?

Second, what about these chemicals in wipes, toothpaste, toys, and plastics?

The FDA banned these antiseptics in washes because scientific studies revealed no benefit over plain soap and water. What about wipes? Is there a difference? Toys and plastics? This is what really scares me. Toddlers putting antibiotic-laced toys in their mouths. I’ve always preferred wooden or fabric toys for the kids for this reason. Toothpaste and dental picks/floss? Now that’s more complicated. There is a paper showing decreased plaque and gingivitis when triclosan is used, but whether or not that decrease influenced overall dental health isn’t known [17]. The potential cost to increased antibiotic resistance in oral, gut, or other microbiomes was not investigated.

Third, what will replace these 19 banned antiseptics?

In 2013, the FDA issued their initial ruling on triclosan and other antiseptics due to the data available at that time. Many companies began removing triclosan at that time and replacing it with quaternary compounds, benzalkonium chloride and benzethonium chloride. The 2016 FDA ruling keeps benzalkonium chloride, benzethonium chloride, and chloroxylenol, under further investigation for safety and efficiency. These quaternary compounds may not be any better than the antiseptics they replace. They may also directly impact human health. Stay tuned for a future post. In my house, we’ll stick to plain old boring soap and water, alcohol, and peroxide.

Banned Antiseptics:

Additional Resources

@Phylogenomics Storify of Twitter responses

Environmental Working Group: FDA ban

Nature Microbiology: Triclosan is Washed Up

Should I Wash My Hands, Doctor – allergies or illness?

 

REFERENCES

 

1. Kim SA, Moon H, Lee K, Rhee MS: Bactericidal effects of triclosan in soap both in vitro and in vivo. J Antimicrob Chemother 2015, 70(12):3345-3352.
2. Aiello AE, Larson EL, Levy SB: Consumer Antibacterial Soaps: Effective or Just Risky? Clin Infect Dis 2007, 45(Supplement 2):S137-S147.
3. Carey DE, Mcnamara PJ: The impact of triclosan on the spread of antibiotic resistance in the environment. Frontiers in Microbiology 2015, 5.
4. Chuanchuen R, Karkhoff-Schweizer RR, Schweizer HP: High-level triclosan resistance in Pseudomonas aeruginosa is solely a result of efflux. Am J Infect Control 2003, 31.
5. Drury B, Scott J, Rosi-Marshall EJ, Kelly JJ: Triclosan exposure increases triclosan resistance and influences taxonomic composition of benthic bacterial communities. Environ Sci Technol 2013, 47.
6. Lankester J, Patel C, Cullen MR, Ley C, Parsonnet J: Urinary triclosan is associated with elevated body mass index in NHANES. PLoS One 2013, 8.
7. Allmyr M, Adolfsson-Erici M, McLachlan MS, Sandborgh-Englund G: Triclosan in plasma and milk from Swedish nursing mothers and their exposure via personal care products. Sci Total Environ 2006, 372(1):87-93.
8. Chalew TE, Halden RU: Environmental exposure of aquatic and terrestrial biota to triclosan and triclocarban. J Am Water Works Assoc 2009, 45.
9. Dhillon GS, Kaur S, Pulicharla R, Brar SK, Cledón M, Verma M, Surampalli RY: Triclosan: Current Status, Occurrence, Environmental Risks and Bioaccumulation Potential. Int J Env Res Public Health 2015, 12(5):5657-5684.
10. Dinwiddie MT, Terry PD, Chen J: Recent Evidence Regarding Triclosan and Cancer Risk. Int J Env Res Public Health 2014, 11(2):2209-2217.
11. Perez AL, Gauthier AM, Ferracini T, Cowan DM, Kingsbury T, Panko J: The Challenge of Predicting Problematic Chemicals Using a Decision Analysis Tool: Triclosan as a Case Study. Integr Environ Assess Manage 2016:n/a-n/a.
12. Witorsch RJ: Critical analysis of endocrine disruptive activity of triclosan and its relevance to human exposure through the use of personal care products. Crit Rev Toxicol 2014, 44(6):535-555.
13. Raut SA, Angus RA: Triclosan has endocrine-disrupting effects in male western mosquitofish, Gambusia affinis. Environ Toxicol Chem 2010, 29.
14. Yueh M-F, Taniguchi K, Chen S, Evans RM, Hammock BD, Karin M, Tukey RH: The commonly used antimicrobial additive triclosan is a liver tumor promoter. Proceedings of the National Academy of Sciences 2014, 111(48):17200-17205.
15. Pycke BFG, Geer LA, Dalloul M, Abulafia O, Jenck AM, Halden RU: Human Fetal Exposure to Triclosan and Triclocarban in an Urban Population from Brooklyn, New York. Environ Sci Technol 2014, 48(15):8831-8838.
16. Yee AL, Gilbert JA: Is triclosan harming your microbiome? Science 2016, 353(6297):348-349.
17. Kraglund F: Triclosan produces statistically significant reduction in plaque, gingivitis and caries but not clinically important benefit. Evid Based Dent 2014, 15.

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