Thursday, February 9, 2017

Antibacterial Germ Fighter Triclosan: A Future Super Germ?

Daily, millions of us, wash our bodies, clean our living spaces and prepare our foods with products containing triclosan. These products are often labeled antibacterial or antimicrobial. Textiles, plastics and some building supplies also contain this chemical. This seemingly simple ingredient, used in so many products, has a growing list of concerns from scientists and regulatory agencies. Concerns about triclosan as a carcinogenic, endocrine disruptor and antibiotic resistance contributor are varied and common.

By itself Triclosan is a powdery substance added to soaps, household cleaners, sanitizers, disinfectants and even building supplies. Known by various names including Irgasan and Microban as well as the more common- Triclosan; it was first developed in the early 20th century. Within the EPA it is a registered pesticide-found on FIFRA. Its uses are as microbicide/microbistats, bacteriostats and as fungicides. Several environmental organizations list Triclosan as a high volume chemical (production/importation exceeds one million pounds annually)(1). It makes an appearance on a plethora of environmental and chemical “use with caution/prudence” lists. Scoring high as an environmental risk by the Environmental Defense Fund (1).


Triclosan works by affecting cell enzymes in much the same way as clinical antibiotics.This action & the resistance it causes concerns scientists


Triclosan is a broadspectrum antibacterial agent that works at targeting enzymes and encouraging mutations within cells. The targeted enzymes perform chemical catalysis across/through cell membranes. The effects of Triclosan on the cell is greater expression/leakage through the cell walls. Triclosan targets and promotes mutations within cells as part of its job. Enzymic activation or degradation are also observed actions of Triclosan. Mainly targeting cells with simple cell walls , it also targets certain intercellular parasitic fungal bacteria called mycobacteria. Mycobacteria are pathogenic organisms that include strains causing tuberculosis and leprosy. (1a)


Observed similarities between clinical antibiotic resistance and resistance to antibacterial triclosan is often noted by scientists. These similarities include resistance in targeting mutations within bacteria and increasing these mutations. Enzyme shutdown with increased disruption of cell wall functions are noted in the same studies ( 1b). Triclosan resistance has been found to affect intestinal and dermal tissue. Several studies have found links of increased potential of antibacterial resistance from Escherichia coli (E. coli) and Salmonella enterica. High levels of antibacterial resistance are often aquired after only 2 or 3 low level exposures( 2 ).


Triclosan’s interaction with other chemicals may allow it to act as a hormonally active agent.


Scientists are beginning to study Triclosan’s interaction with sunlight/heat and with other chemicals like chlorine. In both interactions Triclosan becomes a dioxin, causing possible endocrine disruption(2a). Many species could be affected by Triclosan turned Hormonally Active Dioxin. Because of this knowledge various groups are studing it as an emerging pollutant . It is on the EPA’s “use with caution” list; so several EPA studies have focused on its effects on secondary sexual characteristics in animals.


The effects of triclosan, as an antibacterial, on public health may not be evident yet; but it’s presence in humans and animals cannot be denied. Antibacterial Triclosan is found increasingly in the breast milk of humans and other mammals. Most of the U.S. population have triclosan in their urine(2b). Because of this additive to wastewater and because of runoff water, it is an increasing presence in aquatic life forms including fish and frogs. One US Geological study points to possible antibacterial cellular disruption in animals that live in aquatic environments receiving heavy runoff. Triclosan is found in up to 60% of US water ways according to the same US Geological Survey study (3).

Environmental and Public Health organizations are keeping a watchful eye on Triclosan.


Articles documenting the positive use of triclosan, once common in public health information, are containing more warnings about overuse of this chemical. Triclosan has been a big factor in the EPA questioning its definition of a “persistant” environmental pollutant. No longer is “persistant” applied just to chemicals with long half lives. The term can be applied to man made chemicals, with short half lifes, continually supplied from human interaction in the environment (4).


As an antibacterial pesticide the EPA cautions about Triclosan being an immunotoxicant and sense organ toxicant. When focusing on antibacterials as PPCPs (Pharmaceutical & Personal Care Pollutant) the agency watches the chemical but has little to say about its effect on the the environment. Often featured in emerging pollutant workshops by the EPA and other environmental groups-Triclosan’s antibacterial presence in the environment and in mammals is raising questions and maybe some alarm (5).


Many public health organizations have taken the stance that Triclosan and other antibacterial chemicals are to be used sparingly. In an article on the American Public Health Associations web site there is focus on a University of Michigan study that found hand sanitizer with Triclosan didn’t remove any more bacteria than plain soap. The researchers did point out that E. coli was able to develop resistance at the levels of Triclosan used in hand sanitizers.(6) Daily repeated use of antibacterial Triclosan is strongly discouraged. The American Medical Association, in 2000, went on record stating “Considering the available data and the critical nature of the antibiotic resistance problem, it may be prudent to avoid the use of antimicrobial agents in consumer products(7).”


The World Health Organization, in 2004, set up a consultancy to advise its members and others about antibacterial resistance-including Triclosan. The consultancy was a two step approach: the first step involved training about the human, veteranarian and agriculture uses of antibacterials like Triclosan, the second step focused on teaching the effects of antimicrobials moving into the food chain and the human public health consequences(8).


Concerns advocate for caution with antibacterial products.


Increasingly, more and more products are developed with Triclosan as an ingredient-over 700 are available in the U.S.. Concerns continue to develop about this widely used antibacterial chemical; besides increased resistance from bacteria and clinical antibiotics there are concerns about carcinogenesis and hormone disruption issues. With all the cautionary evidence-the big question is why the U.S public is not warned to “use prudence” with products containing this chemical? How ever Triclosan is used- the repeated listing of “use with caution” is a great warning to live by regarding this unknown, fearful and growing environmental additive.


Sources
1. http://www.scorecard.org/chemical-profiles/summary.tcl?edf_substance_id=3380-34-5#safety_assessment


1a. http://www.cdc.gov/ncidod/eid/vol7no3_supp/levy.htm


1b. http://www.epa.gov/esd/pdf/ppcp711.pdf


2. Page 10 of http://www.who.int/foodsafety/publications/micro/en/amr.pdf


2a. http://www.beyondpesticides.org/pesticides/factsheets/Triclosan%20cited.pdf


2b. http://www.cdc.gov/exposurereport/pdf/factsheet_triclosan.pdf


3. http://toxics.usgs.gov/pubs/OFR-02-94/index.html,


http://toxics.usgs.gov/pubs/OFR-02-94/figure2.html,


http://toxics.usgs.gov/highlights/pharm_watershed/,


Page 47 at http://www.epa.gov/OSP/regions/emerpoll_rep.pdf


4. http://www.epa.gov/esd/pdf/ppcp711.pdf


5. Page 47 http://www.epa.gov/OSP/regions/emerpoll_rep.pdf


6. http://www.apha.org/publications/tnh/archives/2007/Sept07/WebExclusives/soapWEBEX.htm


7. Page 4 at http://www.ama-assn.org/ama1/pub/upload/mm/443/csaa-00.pdf


8. http://www.who.int/foodsafety/publications/micro/en/background.pdf


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