(Beyond Pesticides, October 12, 2011) A new industry-funded study that claims to ‚ÄúReaffirm Safe Use of Triclosan, Triclocarban in Antibacterial Soaps and Washes,‚ÄĚ concludes that triclosan and triclocarban soaps do not facilitate antibiotic resistance and antibiotic cross-resistance. The study, sponsored by the American Cleaning Institute and the Personal Care Products Council, long supporters of the antibacterial pesticide triclosan, dismisses previous independent data that has identified triclosan as a promoter of antibacterial resistance and calls for precautionary measures against the unnecessary but widespread use of antibacterial agents.
The study, ‚ÄúInvestigation of Antibiotic and Antibacterial Susceptibility and Resistance In Staphylococcus From The Skin Of Users and Nonusers Of Antibacterial Wash Products In Home Environments,‚ÄĚ found that there was no statistically significant difference in antibiotic resistance in the bacteria, Staphylococcus aureus, exposed to triclosan and triclocarban soaps compared with those not exposed. The study collected swab samples from the forearms of participants that used triclosan, triclocarban, and a control group that used neither. The study‚Äôs conclusions are not surprising since this industry has been a vocal and active promoter of the antibacterial products they manufacture and represent. Beyond Pesticides has previously responded to the American Cleaning Institute‚Äôs (formerly the Soap and Detergent Association) assertions that antibacterial soaps are ‚Äėsafe,‚Äô even though most studies call for caution with using these substances. There are also several limitations to this study, including the exclusion of pets owners (other than fish), those using antibiotics and topical skin medications, and health care, day care and animal care workers ‚Äď i.e. persons most exposed to various bacterial populations.
Triclosan and its cousin triclocarban have come under fire for their link to many serious human and environmental health threats, including endocrine disruption and a link to adverse fetal development, water contamination and an ever increasing body burden expressed in breast milk, urine and even umbilical cord blood. While announcing plans to review the chemical, the Food and Drug Administration stated that, ‚Äúexisting data raise valid concerns about the [health] effects of repetitive daily human exposure to these antiseptic ingredients.‚ÄĚ
The verdict on triclosan’s and triclocarban‚Äôs potential to promote antibacterial and antibiotic cross-resistance is still out, however it is well-recognized that the main cause of antibiotic resistance remains the use and misuse of antibacterial and antibiotic substances. In the specific instance of triclosan, studies have provided preliminary evidence that it promotes bacterial resistance. Bacterial resistance may occur through mutation of gene constitutions or the uptake of new genetic elements through gene transfer. Such resistance may cause multiple threats, since widespread use of the triclosan may not only result in bacteria that are resistant to triclosan but may also create resistance to other, including unrelated, antimicrobials and antibiotics (cross-resistance). The main concern regarding triclosan‚Äôs ability to promote cross-resistance to the antibacterial/antibiotic agents is that, according to Schweizer (2001), triclosan resistance mechanisms include target mutations, increased target expression, active efflux from the cell, and enzymatic inactivation/degradation. These are the same types of mechanisms involved in antibiotic resistance and some of them account for the observed cross-resistance with antibiotics in laboratory isolates. While some have argued that the high concentration of triclosan found in articles like soap is sufficient to kill even resistant bacterial strains, research has shown this is not necessarily true. A 2006 study published in Microbial Drug Resistance documents that ‚Äúat sublethal concentrations, triclosan inhibits a specific bacterial target, and several mechanisms of resistance to triclosan have been demonstrated.‚ÄĚ
Another study from the Journal of Medical Microbiology finds that in bacterial strains that lack the multiple antibiotic resistance (Mar) phenotype, triclosan selects those that, in addition to triclosan resistance, have also acquired antibiotic resistance. This study also finds that triclosan concentration is very important for the selection of mutants with reduced antibiotic susceptibility. Low concentrations of triclosan lead to the survival of cells with mechanisms of triclosan resistance, suggesting that future generation of the bacteria is also resistant. Studies find that another bacterium Pseudomonas aeruginosa, is intrinsically resistant to high levels of triclosan and can survive in the presence of triclosan concentrations in excess of 1000 őľg/mL. Others have found that triclosan exposure of Escherichia coli (E. coli) selects for tolerant clones and reduces triclosan‚Äôs effect on E. coli., but that this phenomenon was not widespread and limited to E. coli.
There is no doubt that studies looking at triclosan-induced resistance have been conflicting. Suller and Russell in a 2000 study with Staphylococcus aureus saw that while some but not all strains were resistant to several antibiotics and showed low-level triclosan resistance, the mutant strains were not more resistant than the parent strains. Aiello et al., in a 2006 study suggests that longer durations (> 1 year) might provide a suitable environment for emergence of antimicrobial drug‚Äďresistant species in the community setting. However, the European Scientific Committee of Consumer Safety (SCCS) concluded in its 2010 opinion on triclosan and antibacterial resistance that while it is difficult ‚Äúto quantify the risk of development of antimicrobial resistance induced by triclosan applications including its use in cosmetics…there are environmental concentrations in a number of geographically distinct areas high enough to suggest that triggering of bacterial resistance could also occur in the environment.‚ÄĚ The SCCS recommended ‚Äúthe prudent use of triclosan, for example, in applications where a health benefit can be demonstrated.‚ÄĚ
Resistance to antibacterial and antibiotic agents becomes critically important for vulnerable subpopulations, including persons with impaired immune systems, infants and young children, and persons needing the benefit of antibiotics. A recent study identified a fatal outbreak of P. aeruginosa in a hospital as coming from the contamination of triclosan soap dispensers, which acted as a continuous source of the bacterium. Further, a systematic review of research assessing the risks and potential benefits associated with the use of soaps containing triclosan finds that data do not show the effectiveness of triclosan for reducing infectious disease symptoms or bacterial counts on the hands when used at the concentrations commonly found in antibacterial products.
There are many valid concerns regarding triclosan resistance that industry would like to ignore. While the science tries to adequately quantify the phenomena, there are many other important reasons to stay away from triclosan-containing products and maintain a precautionary approach. The scientific literature has extensively linked the uses of triclosan to many health and environmental hazards. As an endocrine disruptor, triclosan has been shown to affect male and female reproductive hormones and possibly fetal development, and also shown to alter thyroid function. The Centers for Disease Control and Prevention (CDC) also has found that triclosan is present in the urine of 75% of the U.S. population, with concentrations that have increased by 42% since 2004. Beyond Pesticides in 2004 began voicing concern about the dangers of triclosan and in 2009 and 2010 submitted petitions to the U.S. Food and Drug Administration (FDA) and the U.S. Environmental Protection Agency (EPA), calling for the removal of triclosan from consumer products. Since then, many major companies are quietly and quickly removing triclosan from their products. Colgate-Palmolive, makers of SoftSoap, and GlaxoSmithKline, makers of Aquafresh and Sensodyne toothpastes, have reformulated these products to exclude triclosan, according to media reports. Others, including Johnson & Johnson, L‚ÄôOreal, The Body Shop, and Staples, have started phasing it out of products.
Take Action: Don‚Äôt be fooled by industry sponsored data. Avoid triclosan-containing products such as soap, toothpaste, toys and other plastics. Join the ban triclosan campaign and sign the pledge to stop using triclosan today. Avoid products containing triclosan, and encourage your local schools, government agencies, and local businesses to use their buying power to go triclosan-free. Urge your municipality and workplace to adopt the model resolution that commits to not procuring or using products containing triclosan.
Source: The Sacramento Bee
All unattributed positions and opinions in this piece are those of Beyond Pesticides.