Health Care Without Harm Europe Newsletter - The Campaign for Environmentally Responsible Health Care
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Do we really need silver in healthcare?

Silver is being heavily promoted as a panacea to infection problems in hospitals - but there is worryingly little discussion of what could happen to the environment if its use became standard and widespread.

by Eva Haxton, Uppsala University Hospital

In the last decade, healthcare has become the largest consumer of silver from all industrial sectors. In less than five years, use of silver has spread from soaps to full room concepts in hospital wards.

The naturally bactericidal properties of silver, combined with emerging problems of antibiotic resistance in bacteria and fear of multi-resistant strains such as MRSA, have encouraged its introduction into many products commonly found in hospitals.

Silver is now used in textiles, ceilings, walls, floors, furniture, clothes and shoes. Silver-treated medical devices exist for almost every purpose.

However, in spite of possibilities of silver for reducing infection rates, there are good reasons for being wary about the increasingly ubiquitous use of silver in healthcare and elsewhere.

One particular cause of concern being investigated at Uppsala University is whether or not using silver could make bacteria resistant to antibiotics.

The assumption has been that because silver is not an antibiotic, then at worst bacteria will end up resistant to silver.

In fact, it seems that bacteria which develop resistance to silver undergo the same changes as when they become resistant to certain classes of antibiotics (including beta-lactams, which account for 50% of antibiotics used).

This hypothesis is supported by evidence from laboratory experiments at Uppsala University, where resistance to silver has been found to be associated with antibiotic resistance.

So by introducing silver as a way to kill bacteria, we could end up encouraging the development of antibiotic-resistant bacteria rather than preventing their spread.

Another problem is the possible effect of silver on the environment. Uncontrolled use of something which in water is highly toxic to bacteria and fish could have serious repercussions for the food chain.

Coinciding with increased usage of silver, Swedish researchers have discovered that silver levels are rising in areas of land sprayed with treated sewage or in contact with wastewater [Bra slam och fosfor i kretslopp. Nv Rapport 5214, 2003].

The problem here is a potential drastic reduction in soil fertility, as silver kills the bacteria which break down organic matter into nutrients which can be absorbed by plants.

These concerns and discoveries have lead the Swedish government to take a number of precautionary measures against silver pollution.

For example, in 2006 the national Swedish pharmacies chain, Apoteket AB, decided to stop selling band- aids containing silver.

The Swedish Environmental Protection Agency has also set a goal of limiting the amount of silver added to land, which translates into a maximum limit of 15mg of silver per kilogram of dry matter from wastewater treatment plants.

In Stockholm County Council, silver is being treated as a medication: its use must be approved by a senior doctor, and it is prescribed rather than used ubiquitously.

Without research into how much silver will be introduced into waterways from widespread use in medical care, and what the effects of this will be, it would be foolish to start using silver in larger amounts.

Unfortunately, in most places this is already happening. Use of silver has focused on benefits for some patients with little discussion of what would happen if the use of silver became standard and widespread.

These issues need to be resolved before silver is sold in large quantities in healthcare - or we could easily be solving one problem at the expense of introducing another.

Links

MRSA and the use of silver dressings: overcoming bacterial resistance (pro-silver article sponsored by Smith and Nephew) 

Silver in Health Care: Antimicrobial Effects and Safety in Use

FoE Report on nanotechnology in food packaging (esp. p15 onwards)

About Uppsala University Hospital (UUH)

UUH is researching bacterial resistance to silver and cross-resistance to antibiotics. They have produced clinical studies on bacterial flora affected by silver, concerning bacterial resistance and antibiotic resistance. In in vitro studies, UUH has found it easy to develop bacterial resistance and antibiotic resistance with silver.

UUH has also studied the development of bio films and how they are affected by silver, particularly looking at indwelling catheters and central vein catheters containing silver. UUH is also studying wound dressings and band-aids, where silver ions have now been replaced by nano silver. They have seen uptake in tissue and also an accumulation of silver around nerves.

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