Antimicrobials - are the ingredients safe?

6th of December 2012
Antimicrobials - are the ingredients safe?

A recent US study shows the increased use of hand sanitisers is having a knock-on effect on our lakes and rivers, with ingredients like Triclocarban and Triclosan coming under increased scrutiny for their impact on environmental and public health. ECJ takes a closer look at these ingredients, their potential risks when used in hand hygiene products, and the possible alternatives.

According to scientists at Arizona State University in the USA ingredients from hand sanitisers are filtering into water reserves – with a potential impact on the environment, wildlife and people. Researchers analysed fresh water sources in the state of Minnesota and found widespread evidence of the presence of both Triclosan and Triclocarban – both active ingredients commonly found in antimicrobial soaps.

Experts traced the products from homes to sewers to wastewater treatment plants and eventually downstream into natural waterways. Both Triclocarban and Triclosan have been scrutinised by public health bodies in the past over concerns about their impact on environmental and public health.

Professor Rolf Halden, director of environmental security at Arizona State University's Biodesign Institute, said: "This study underscores the extent to which additives of antimicrobial consumer products are polluting freshwater environments in the US."

The Food and Drug Administration in the US has previously claimed that research shows "valid concerns" about Triclosan including the risk that it can disrupt the body's endocrine system and help create bacteria that are resistant to antibiotics.

Bearing all this in mind, just how concerned should we be about the ingredients being used in antimicrobial soaps? All hand hygiene focus in recent years has been on killing of bacteria and prevention of infection following numerous scares worldwide, but at what cost?

In an effort to determine just which ingredients give cause for concern, ECJ spoke to Dr John Hines, research and development director for Deb Group in the UK, which has a long history in workplace hand hygiene. “It’s actually not always easy to determine what concerns to take seriously,” he begins,  “because at some stage concerns are raised about most of the ingredients being used today. And navigating those concerns within R&D is quite difficult.

“As a company producing antimicrobial soaps and hand sanitisers, if we were sensitive to all of the concerns being raised by various studies we’d run out of ingredients to use. At the other end of the scale we could take the view that we would use anything that’s legally allowed.”

Hines continues: “The problem with that is legislation can take time to catch up with information becoming available so at Deb we have chosen to sit somewhere in the middle. Ultimately we want to use ingredients that are proved to be safe.”

One ingredient that is giving genuine cause for concern is Triclosan. Although it is certified for use within the US and Europe, there is scientific evidence to suggest that it does affect marine life. That evidence is now so strong that there will be legislation in Europe whereby products containing Triclosan above certain levels will have to be labelled as being an environmental hazard.

Triclosan is what’s known as a phenolic biocide in that it inhibits the metabolic pathway common to many bacteria and stops them converting food to energy – kills them off in effect. “For many years it was viewed as being completely safe. It is not toxic to humans, it has low skin irritation potential,” Hines explains. In the wider environment it is implicated as an oestrogen mimic and inhibitor of photosynthesis.

“It is acutely toxic to many types of aquatic species, and it can also bioaccumulate because it does not get metabolised by many species. It can exist without problem at low levels in algae, for example, but as it gets higher up the food chain it starts to accumulate and multiply. And at those higher levels there is higher toxicity.”

Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost.

“So for fish and higher species the concern is hormone balance disruption,” Hines goes on. “In certain fish, for example, this could mean imbalances in sexes so whole species become unbalanced – potentially resulting in disruption of populations.

“This may sound catastrophic but we must bear in mind that scientists are always looking for very small impacts. It must be put into context. However we also must examine the ethics of whether it’s right for us as humans to use an ingredient that could have such an impact on our marine life. Triclosan is, after all, a powerful ingredient – it’s designed to kill microbes.”

Another group of potentially problematic ingredients come under the term Quats (Quaternary Ammonium Chlorides), which are used mainly in antimicrobial soap products. “Quats do not carry any risk of disrupting the environment, however various types of bacteria have developed resistance to them,” Hines explains.

Antibiotic resistance risk

“They are also very persistent on hands, which means over time users can end up with effectively a ‘layer’ on their skin. Inevitably some people would be at risk of skin irritation, perhaps contact dermatitis.”

CHG, or Chlorhexidine gluconate, is a chemical antiseptic effective on both Gram-positive and Gram-negative bacteria – although to a lesser extent on Gram-negative. Used widely in mouth rinses and skin cleansers, CHG is used mainly in antimicrobials and alcohol-free sanitisers. It does have other limitations in that it can be slower acting than some other ingredients. Known to be harmful in high concentrations, various scientific papers have reported complications with low level exposure too.

Amid the endless scientific reports raising concerns about various ingredients used in hand hygiene products, Deb has established a definite strategy in the development of new formulations. “We will focus on using ingredients that do not kill microbes through a pharmacological reaction,” explains Hines. That is, an interaction that occurs between a living organism and a chemical that affects normal or abnormal biochemical function.

“We prefer to work with ingredients that act through a mechanical action, which is where alcohol and hydrogen peroxide come in. We are steering clear of metabolic/pharmacological actives.”

As a company Deb is unhappy about the controversial ingredients mentioned above being used in products that are left on the hands – namely hand sanitisers that are not rinsed off. “There is a risk of sensitisation over time and it will be a lifelong risk once it has happened,” adds Hines.

“There is also a very real risk of resistance to antibiotics with the antimicrobial ingredients now being widely used. It’s far less likely that a bacterium would developed a resistance to alcohol, for example, because alcohol literally blows the cell up.”

With the launch of its latest hand hygiene soap, OxyBac, Deb has used Accelerated Hydrogen Peroxide (AHP) technology to reach what Hines describes as “a similar stage of risk with antimicrobial soaps to that reached with alcohol in sanitisers”.

Hydrogen peroxide is non-specific, so far less likely to develop a resistance than more traditional ingredients, says Hines. It boasts broad efficacy, has passed clinical testing, is proven to be non-irritating and contains no chemicals of concern. And because it breaks down to water and oxygen there should be no environmental impact.

“Of course many customers still remain unconvinced about the use of hydrogen peroxide in a hand soap because of its association with bleach and hair dye,” Hines explains. “It’s also used widely in wound care and surface disinfection at fairly high levels.

“This formula we have developed, however uses much lower levels of hydrogen peroxide and enables them to be more effective thanks to our work with Virox – the company we developed the technology with.”

Challenging for manufacturers

While consumers may find it difficult to make the right choices about their hand hygiene formulations, for manufacturers too the situation remains challenging. “Ideally we manufacturers would like the regulators to work far more quickly so we could know for sure exactly what’s safe and what’s not,” says Hines. “I would like legislation to go deeper and offer us more guidance.

“Hand hygiene products must be made from ingredients that are safe, non-toxic, with no potential for sensitisation or resistance. From our point of view the best options now are alcohol and hydrogen peroxide.”

As far as the end user is concerned, Hines says they can only really rely on manufacturers’ claims and statements. “The most important feature of an antimicrobial is efficacy of course – above 99.9 per cent is usually quoted. It’s also vital to look at the breadth of kill that’s being claimed – for example Gram-positive and Gram-negative bacteria, mould etc. And of course it must meet all European norms for this category of products.

“Users should also expect to see the manufacturer making some statement about safety etc, and the environmental profile of its products. And in food and healthcare, they should certainly be considering bacterial resistance. Any ingredients that have a metabolic action will carry the potential for resistance.”

In conclusion Hines says: “Another aspect that must not be forgotten of course is how pleasant the product is to use, because if staff are happy to use their hand hygiene product, it encourages compliance, which in turn drives up hygiene standards.”


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