For nearly a century we have used antimicrobials to wage a war on bacteria. We have learned to fight off these ‘enemies’ by using stronger and stronger antibiotics and other antimicrobial weapons. As bacteria have found ways to resist the lethal effects of one antimicrobial weapon, we have discovered and unleashed new antimicrobials.
However, there is now a real worry that we may be running out of options to tackle antimicrobial resistant (AMR) bacteria – the superbugs – those with resistance to a variety of different antimicrobials. If the problem of superbugs continues to worsen, it will – in effect – result in a return to the pre-antibiotic era, where a bacterial infection from a simple operation, a commonplace disease, or even a scratch could result in the loss of a limb or even the loss of a life.
In response to this looming health crisis, Australian scientists and health care experts have made clear recommendations for more than a decade. In order to maintain the effectiveness of antimicrobials in our hospitals – where they are needed most – we need to seriously reduce their usage elsewhere.
In some clinical settings, the medical community has been turning to silver as an antimicrobial of last resort to line wound dressings, catheters, stents and other sensitive clinical surfaces. However, as with antibiotics, the use of antimicrobials like silver ultimately drives the selection of bacteria with genes that make them able to withstand the usually toxic effects of silver.
Thanks to the promiscuous nature of bacteria, they regularly share small pieces of DNA containing whole cassettes of genes which confer resistance to multiple antimicrobials. Indeed, there is already evidence of bacterial resistance to silver alongside antibiotic resistance in many clinical settings.
Relatively new developments in nanotechnology now allow the production of silver nanoparticles – commonly referred to as nano-silver – which can be embedded in a range of materials and devices. Because of its extremely large relative surface area, nano-silver is a much more potent antimicrobial than bulk silver.
Despite its clinical importance, hundreds of companies around the world have seen a marketing advantage in including nano-silver as an ingredient in everyday products. Nano-silver is now used as an antimicrobial in toothpastes, pet shampoos, fabric softeners, bath towels, cosmetics, deodorants, baby clothes, baby bottles, refrigerators, food storage containers, kitchen cutting boards, underwear, ATM buttons, industrial disinfectants, agricultural pesticides, handrails for buses and more.
Here in Australia, many people already come into contact with nano-silver everyday. Antimicrobial experts such as Professor John Turnidge have warned that using such a powerful antimicrobial in these everyday products is not only unnecessary, but dangerous.
Concerns have been raised that the widespread non-clinical use of nano-silver as a surface antimicrobial will compromise the microbial diversity of our immediate environment (e.g. skin) and wider environment (e.g. soil and water). This in turn will eliminate the vast numbers of protective microbes, and allow the flourishing and spread of antimicrobial resistant bacteria. Furthermore, experts now warn that bacteria that are resistant to nano-silver are often also resistant to other antimicrobials and antibiotics.
In response to these warnings, some companies have claimed we have used silver for thousands of years without any demonstrated harm. However, the quantity of nano-silver particles currently in use, the strength of their antimicrobial properties, the contexts of their use, and the current antibiotic resistance crisis are unprecedented.
The good news is that seriously restricting our uses of antimicrobials has been proven to lead to lower levels of antimicrobial resistance. We only need look at how the restricted use of quinolone antibiotics in both humans and animals in Australia has maintained low levels of bacterial resistance, compared to elsewhere around the world. Sweden also has some of the lowest levels of AMR in the world, thanks to massive education and surveillance programs that were launched in the mid-1990s.
But while Australian scientists and health care experts have recommended for more than a decade that we need to reduce overuse of antimicrobials, their warnings have not been heeded.
The Australian Senate is currently investigating why so few of these expert recommendations have been implemented, and what effective steps can be taken.
Friends of the Earth Australia, the Public Health Association of Australia, the Australia Institute and the National Toxics Network have released a statement calling on the current Australian Senate inquiry to recommend urgent steps to seriously restrict the overuse of antibiotics in both human and agricultural applications. The groups are also calling on the Government to restrict the unnecessary use of potent antimicrobials such as nano-silver in consumer products, and in order to save them for hospital use.
More than a decade of relative inaction in regulating the use of both antimicrobials and applications of nanotechnology by our Federal Government has contributed to the crisis we are now faced with. But this senate inquiry offers a chance to get back on track.
The time for stalling is over. Urgent regulatory action is needed if we are to preserve the effectiveness of available antimicrobials and ensure our nation’s health.
Dr Gregory Crocetti, Friends of the Earth Nanotechnology Project Collective.
This article was first published on the ABC Environment website