It has been suggested in medical circles for quite some time that a thorough washing of hands with regular soap and water is as effective in removing bacteria as using an antibacterial soap or hand cleaner.
Extensive studies of the effects of some chemical ingredients are lacking. One antimicrobial chemical ingredient known as triclosan has been identified by some as concerning.
But some say antibacterial soaps and "waterless" hand cleaners containing triclosan may be harmful to cats and other animals if ingested. One shelter has discontinued its use upon the advice of a shelter consultant, just to be on the safe side.
I've used antibacterial soaps and my cat, Jenny, often tries to lick my hands when I join her in bed at night. It was therefore of great interest when I read about the debate surrounding triclosan.
What is Triclosan?Also marketed as Microban and Biofresh, triclosan is an antimicrobial ingredient approved for use in countries around the world in a wide range of personal care, health care, and other consumer products. It is meant to control the growth of potentially harmful bacteria in uses as diverse as personal hygiene, health care settings, and food preparation areas.
Like many chemicals, at high enough doses, triclosan can also be toxic and its potential as a pesticide or toxin at high doses has been noted by some expert agencies.
How Could Products Containing Triclosan Harm Cats?I have not found any studies proving that triclosan can specifically harm cats. However, one study, published by the Toxicological Sciences Journal, concluded that "triclosan exposure significantly impacts thyroid hormone concentrations in the male juvenile rat."
Antibacterial hand cleaners are not meant to be swallowed, but a cat might swallow enough to become ill when licking the hand of an owner who has recently used these products.
Can Triclosan Lead to Mutant Bacterial Strains?My initial concern was more that the ingestion of such a powerful antibacterial product might kill off the "friendly bacteria" in a cat's bowels, which might have a deleterious effect on an immunocompromised cat.
Infectious diseases experts have been debating the risk of developing drug resistance in the setting of triclosan containing hand sanitizers for several years now. One microbial drug resistance paper describes these concerns about resistance:
Although the number of studies elucidating the association between triclosan resistance and resistance to other antimicrobials in clinical isolates has been limited, recent laboratory studies have confirmed the potential for such a link in Escherichia coli and Salmonella enterica. Thus, widespread use of triclosan may represent a potential public health risk in regard to development of concomitant resistance to clinically important antimicrobials.
Along those same lines, there has been a study conducted to test the theory that antibacterial soaps may lead to bacterial resistance to the penicillin class of antibiotics, according to Kristina Duda, R.N., About.com Guide to Cold and Flu. It would appear that the jury is still out, as Kristina's bottom line was "More research is needed to come to any definite conclusions about the risks or benefits of antibacterial products."
The CDC voices concerns about antibacterial products at the 2000 Emerging Infectious Diseases Conference in Atlanta. Dr. Stuart B. Levy of Tufts University School of Medicine, Boston presented several studies about the possible harmful effects of Triclosan and other antibacterial products, both in hospitals and in the home. The introduction to Dr. Levy's paper said:
The recent entry of products containing antibacterial agents into healthy households has escalated from a few dozen products in the mid-1990s to more than 700 today. Antibacterial products were developed and have been successfully used to prevent transmission of disease-causing microorganisms among patients, particularly in hospitals. They are now being added to products used in healthy households, even though an added health benefit has not been demonstrated. Scientists are concerned that the antibacterial agents will select bacteria resistant to them and cross-resistant to antibiotics. Moreover, if they alter a person's microflora, they may negatively affect the normal maturation of the T helper cell response of the immune system to commensal flora antigens; this change could lead to a greater chance of allergies in children. As with antibiotics, prudent use of these products is urged. Their designated purpose is to protect vulnerable patients.
Dr. Levy's paper tells of a new initiative,between the Alliance for Prudent Use of Antibiotics (APUA) and the University of Illinois, funded by the National Institute of Allergy and Infectious Disease. Titled ROAR (Reservoirs of Antibiotic Resistance), this project "focuses on monitoring and managing the commensal bacteria that harbor pools of resistance genes that can be passed on to pathogens. Through education, APUA strives to foster control of pathogens without decimation of the non-pathogens," and concludes: "In this goal, prudent use applies to both antibiotics and antibacterial products."
Dr. Levy is director of the Center for Adaptation Genetics and Drug Resistance, professor of molecular biology and microbiology, and of medicine, Tufts University School of Medicine, Boston.
Since Dr. Levy's paper, several other peer-reviewed papers have emerged with more mixed messages.
Since the practice of "safe rather than sorry" has served me well in the past, and most experts agree that handwashing is as good as hand sanitizer, I will henceforth favor careful handwashing over the use of products containing triclosan, which my cats might ingest. I think that fits APUA's definition of "prudent use." On the other hand, I will try to use common sense with regard to the other products which contain this chemical.