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Nanosilver Use Prompts Worries of Resistant Bacteria

The advent of nanosilver products raises the possibility of new strains of silver-resistant bacteria, although there’s little evidence of that.
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Could the use of nanosilver products create another problem for medicine — strains of bacteria that are resistant to silver? Although silver is not used to treat disease, it is used in hospital settings to speed wound-healing, prevent eye infections in newborns and as a coating for catheters, where it can cut infection rates.

Here, too, there is much surmise and not much evidence, although researchers do know there are strains of bacteria that have developed resistance to silver.

“If [nanosilver] is used without restriction, then you’re increasing the chances that a number of microbes will develop resistance to it,” says Andrew Maynard, chief science advisor for the Project on Emerging Nanotechnologies at the Woodrow Wilson International Center for Scholars.

Maynard says he worries especially about bacteria that develop resistance to the major classes of antibiotics and silver.

But Dr. David Weber, an infectious disease and public health expert at the University of North Carolina in Chapel Hill, isn’t convinced that silver resistance will prove much of a problem. Resistance to antibiotics occurs quite readily in bacteria once prolonged exposure to, say, penicillin, occurs. But there’s little reason to suppose that resistance to silver would develop so easily, he says.

An antibiotic like penicillin works by hitting a bacterium in a limited fashion, at specific sites. Because the killing is done precisely, the bacterium has a good chance of developing a mutation that would confer resistance.

In contrast, silver kills microbes in a broad, unspecific fashion — like tossing a bomb at a bacterium. It hits many essential points such as a bacterium’s entire respiratory system. This makes it much more difficult for silver-resistance to develop.

And even if tolerance did develop, Weber says, increasing the dose of silver the bacterium is exposed to will solve the problem in most cases.

Sources: Los Angeles Times

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Are Nano-Foods the Next Scary Items?

Those consumers already worried about genetically engineered or cloned food reaching their tables may soon find something else in their grocery carts to furrow their brows over – nano-foods.

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Consumer advocates taking part in a food safety conference in Orlando, Florida, this week said food produced by using nanotechnology is quietly coming onto the market, and they want US authorities to force manufacturers to identify them.

Nanotechnology involves the design and manipulation of materials on molecular scales, smaller than the width of a human hair and invisible to the naked eye. Companies using nanotechnology say it can enhance the flavor or nutritional effectiveness of food.
US health officials generally prefer not to place warning labels on products unless there are clear reasons for caution or concern. But consumer advocates say uncertainty over health consequences alone is sufficient cause to justify identifying nano-foods.

“I think nanotechnology is the new genetic engineering. People just don’t know what’s going on, and it’s moving so fast,”Jane Kolodinsky, a consumer economist at the University of Vermont, said at the conference.

American consumers are generally more complacent about genetically modified or cloned foods than their counterparts in Europe. But Michael Hansen, a senior scientist with the Consumers Union, said polls show that 69% of Americans are concerned about eating cloned meat.

He said that in focus groups run by the US Food and Drug Administration, no parents were willing to feed their children meat from cloned animals or their offspring.

New consumer products created through nanotechnology are coming on the market at the rate of 3 to 4 per week, according to an advocacy group, The Project on Emerging Nanotechnologies (PEN), based on an inventory it has drawn up of 609 known or claimed nano-products.

Nano-products in common use today include lightweight tennis rackets and bicycles, and sunscreens containing clear, nonwhite versions of zinc oxide and titanium dioxide. On PEN’s list are three foods – a brand of canola cooking oil called Canola Active Oil, a tea called Nanotea and a chocolate diet shake called Nanoceuticals Slim Shake Chocolate.

Sources
: The Times Of India

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