Dirty Money! Banknotes Carry An Abundance Of Disease-Causing Bacteria

Researchers have found that banknotes harbor potentially pathogenic and antibiotic-resistant strains of bacteria.

AsianScientist (May 24, 2017) – If a commonly used item passed from person to person everyday around the world was found to carry potential harmful microbes, would you continue to use it? In a study published in Frontiers in Microbiology, researchers from the University of Hong Kong have found that 50 percent of all environmental bacteria can be found on banknotes.

To investigate how microbes are passed between humans and how antibiotic resistance can be spread around the world, a team led by Dr. Li Jun scraped bacteria from the surface of banknotes collected from hospitals and metro stations around Hong Kong in areas of varying population density.

Despite doubt as to whether microbes can even survive on banknotes, the researchers found that the banknotes offer an environment that can, indeed, accommodate living bacteria. Over one third of the bacteria identified on the banknotes consisted of potentially pathogenic species, including potentially lethal bacteria such as Escherichia coli and Vibrio cholera.

“In short, banknotes act as a medium ‘absorbing’ bacteria from other environments and the potential pathogens live quite well on the banknote surface,” said Li.

Comparing the microbes found on banknotes with peoples’ hands, metro station air, drinking water and marine sediment, Li and his team found that the banknotes harbor a much higher diversity of bacteria than that of the environmental samples.

When comparing the number of antibiotic-resistance genes between banknotes and the other environmental samples, the researchers found that the banknotes have a significantly higher abundance than other samples. Of particular interest were clinically important antibiotic-resistance genes which were also higher in the banknotes.

“The high amount of antibiotic-resistance genes found from the banknotes is considerable and can potentially lead to the circulation of antibiotic resistance to humans and other environment,” Li suggested.

When evaluating the dissemination potential of the identified antibiotic-resistance genes, researchers found that the banknotes have a significantly higher potential than the environmental samples. Combining the clinically important antibiotic-resistance genes with the high dissemination potential suggests currency could possibly pose a health risk.

Li hopes that the findings of this study encourage a greater awareness of the potential risks in handling currency.

“The most important recommendation we could raise is that before a cashless society develops, the banks and government should pay extra attention to the hygiene problem of the currency, which is still frequently used in our daily life,” he said.

“We recommend some routine disinfection of the currency from the bank, public service ads reminding people to pay attention to wash the hands after touching currencies and the promotion of more electronic payment service, like mobile payment. We particularly would like to see the politicians and policy-makers inspired by this study.”

The article can be found at: Heshiki et al. (2017) Toward a Metagenomic Understanding on the Bacterial Composition and Resistome in Hong Kong Banknotes.


Source: Frontiers; Photo: Pexels.
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