Weren’t anti-microbial agents considered safe for humans to use and not suppose to be harmful in nature? In recent studies, triclosan, an antibacterial compound is shown to be a harmful agent to humans rather than being helpful in keeping bacterial illnesses away. Presently, antimicrobials agents triclosan and triclocarban are examples of widely used antimicrobials agents in personal care products in United States and many other countries worldwide1. Triclosan is a 2,4,4- tricholoro-2-hydroxydiphenyl ether and triclocarbon is a 3,4,4 – trichlorocarbanilide organic compound.
One of the more common antimicrobial agents used in many househould products each year, triclosan is a synthetic, lipid-soluble, broad spectrum anti-microbial agent that was first used in health care setting in 1972 and then used in the toothpaste making industry in 1985 in Europe 2. From then onwards, triclosan has been approved by the US Food and Drug Administration (FDA) to be used in personal care products, household items, and in hospital settings to control the spread of bacterial illnesses in medical devices 2.
In addition to FDA approving the use of triclosan as an over the counter drug for use in personal items and household items, the US Environmental Protection Agency (EPA) also regulates triclosan as an anti-microbial agent for the protection of polymers and plastics. However, recent studies prove that anti-microbial agent triclosan is turning to be more harmful than beneficial to humans even though it is effective with high efficacy levels in its mechanisms of action by inhibiting bacterial growth.
The word “anti-microbial” has an automatic positive connotation and can also be seen as a misnomer because of the negative effects it has on the human population rather than promoting good health. In the United States, studies prove that triclosan is known for its high anti-microbial effectiveness and is readily available over the counter drug for personal use approved by FDA and EPA. The FDA regulates triclosan by making it readily available drug for use in hand soaps, deodorants, toothpaste, laundry detergents, fabric softeners, facial tissues, and antiseptics for wound care and medical devices.
In addition, not knowing its possible harmful effects, FDA approved the usage of 0. 3% triclosan in Colgate Total toothpaste to prevent gingivitis tooth infection and cavities in humans in 1997 2 . Furthermore, triclosan is also used to control the spread of methicillin-resistant Staphylococcus aureus infections in hospitals and in surgical clothing and sutures to prevent bacterial colonization of the surgical wounds2.
Because of the usage of triclosan in the household and care products, human population can get direct exposure to triclosan through ingestion or dermal contact, spread in the environment which can lead to dangerous and harmful environment. Studies show triclosan deposits are found in finished drinking water, surface water, wastewater, wild fish, and in environmental sediments in some of the states around the United States2. The studies proved that mechanisms of action of triclosan are efficient in inhibiting the growth of bacteria by intercalating into the bacterial membranes and disrupting the membrane activities of the bacteria.
In addition, triclosan inhibits the enoyl-reductase of type II fatty acid synthase involving in the bacteria’s lipid biosynthesis2. Triclosan is known to be more effective against gram-positive bacteria than gram-negative bacteria with being highly effective against Staphylococcus aureus. Furthermore, triclosan acts as a bacteriostatic at lower doses in any substance and bactericidal at higher doses. When acting as a bactericidal, triclosan acts against many different targets including the cell membrane and can act as an anti-viral, anti-fungal, and anti-malarial2.
According to Fang et al. , the mechanisms of actions of triclosan in different household items proven by the American Medical Association in 2002 determined that triclosan containing soaps were efficacious. However, the research study found that triclosan does not reduce the bacterial counts on hands to a greater extent than a plain soap without any anti-microbial agent unless triclosan is added in high concentrations which then can be more harmful to humans than safe.
In addition, an inner city study collected data for one-year period and concluded that there was no statistical difference between the use of “anti-microbial” household items like detergents and soaps compared to the use of identical products without anti-microbial agents in the household items. Studies examining the usage of triclosan in dentrifices concluded that persons using dentrifice with triclosan in it had 27% less plaque than individuals using dentrifices without triclosan2. However, the same study revealed that dentrices with combination of triclosan and zinc citrate were not effective against plaque or gingivitis2.
Additionally, in a study that evaluated the efficacy of triclosan in sutures indicated that sutures with triclosan produced a 3-log reduction in the growth of Staphylococcus aureus in guinea pigs and 1-log reduction in the growth of E-coli bacteria in mice compared to sutures without triclosan2. Other examples include comparison of an anti-bacterial toothbrush containing triclosan-coated tufts with a regular toothbrush without triclosan which also did prove to not inhibit the bacterial growth on the anti-bacterial toothbrush2.
It is noted that triclosan does inhibit the growth of bacteria; however the difference between using an anti-microbial household item and a regular household cleaning item is not much in terms of being safe from the bacterial illnesses. For example, it can be seen in the above paragraph that soaps that contain triclosan have not been proven to be more effective in preventing normal household illnesses than ordinary soap.
Currently, research shows triclosan can be toxic and get into the circulation system of humans via absorption through the mucous membranes of the oral cavity and gastrointestinal tract after oral exposure, through the skin, and through the mucosal tissues. It can act as a selective inhibitor of the glucuronidation and sulfonation of phenolic xenobiotics in human liver as well2. Triclosan is a slow binding inhibitor of human type I fatty acid synthase and is shown to inhibit cell growth of SK-BR-3 human breast cancer cells3. Studies with P. aeruginosa, Mycobacterium smegmatis and Mycobacterium tuberculosis and S. ureus showed that triclosan acts on a bacterial target in the bacterial fatty acid biosynthetic pathway, NADH-dependent enoyl-acyl carrier protein reductase or in homolog InhA in M. smegmatis and M. tuberculosis4.
Triclosan can form a stable ternary complex through interactions with amino acid residues of the active enzyme site and can act as a site-directed inhibitor of the enoyl protein reductase. In addition to these detrimental effects that can cause toxicity in humans or triclosan resistance, high concentrations of triclosan in anti-microbial products can also cause cell lysis through the inhibition of lipid, RNA, and rotein synthesis4.
Toxicity of triclosan depends on the route of administration with intravenous administration through mucosal tissues showing the greatest degree of toxicity which might lead to dangerous side effects. For example, the study by Fang et al showed that through dermal route, the human participants had edema and dermal erythema as a side effect of triclosan in palomolive soap2. Additionally, the increased use of anti-bacterial in household products has been linked to increased allergies in children.
Further studies specific to triclosan have shown that it affects reproduction in lab animals, produces toxic chemicals such as dioxin and chloroform when it reacts with other chemicals like the chlorine in water and the worse effect of causing cancer in human population3. A study by British researchers found that triclosan has estrogenic and androgenic hormone properties and exposure could potentially contribute to breast cancer1. Thus, there are many proven studies that explain the dangers of using excessive triclosan amounts in househould products and should be avoided if possible.
In addition to triclosan causing known harmful systematic and environmental side effects, the problem of bacterial antibiotic resistance is also a result of long antibiotic use that has been studied for long by researchers. Triclosan’s increase in creating more potent strains of bacteria can lead to increasing antibacterial resistance which is a contributing factor to many household illnesses because of usage of “anti-bacterial” household products. This is due to the fact that triclosan kills most of the colonies of bacteria that it encounters and bacteria that survive become harder to kill increasing the bacterial resistance.
It is evident that bacteria use different mechanisms to develop resistance to any biocide. Thus, the problem of bacteria becoming resistance to triclosan through target mutations, active efflux and degradative enzymes is on the rise presently. For example, in a laboratory study with triclosan to study target mutation, scientists showed that fabI mutations caused cross-resistance with other antimicrobial agents in E-coli. Thus, certain biocides share targets with antibiotics and greater use of biocide will select resistance against useful drugs like tricosan4.
Continuing, triclosan resistance in M. megmatis and M. tuberculosis caused resistance to isoniazid which is a drug used to treat the tuberculosis infections4. Another mechanism of triclosan resistance is the efflux from the bacterial cell. Bacteria express efflux pumps in the nodulation cell division family, the major facilitator superfamily (MFS), the small multidrug resistance family (SMR), the ATP binding cassette (ABC) family and the multidrug and toxic compound extrusion (MATE) family4. Schweizer also demonstrated that all of the family transporters catalyze the drug efflux through the required energy in the form of ATP and proton motive force4.
Finally, the most recent studies have two findings that conclud that triclosan and antibiotic resistance are connected to each other. First, triclosan and antibiotics share multidrug efflux systems as a mechanism of resistance and select similar mutations in regulatory loci as a mechanism of resistance. Second, M. tuberculosis regulating mutation leading to isoniazid resistance was also seen in triclosan resistance4. In conclusion, since both triclosan and antibiotics are linked, it is possible that widespread use of triclosan in many household products may lead to antibiotic resistance and triclosan resistance.
Antibacterial resistance is not the only health concern associated with triclosan. Studies have proven recently that the increased use of antibacterials with triclosan in household products can be dangerous and more harmful than beneficial because not only triclosan can affect systemic routes or can contribute to bacterial resistance; it also poses a threat to the environment. It is toxic to algae and accumulates in fish. This major issue is becoming larger as many products that contain triclosan are now washing down into the water systems, making triclosan a common contaminant of streams and rivers.
Thus, causing a bioaccumulation of triclosan in organisms in water and spreading through aquatic and terrestrial food webs. In addition, triclosan also has been found in blood, urine sample and in breast milk of humans around the world1. While public who uses triclosan products daily have higher levels of the chemical in their systems, consumers who do not use triclosan on their skin are exposed to the chemical through food, water and through the usage of household products.