Indian paper currency notes carry micro-organisms that have potential to spread diseases.


(Illustration: C R Sasikumar)

Abstract :

                  Fomites are a well-known source of microbial infections and previous studies have provided insights into the sojourning microbiome of fomites from various sources. Paper currency notes are one of the most commonly exchanged objects and its potential to transmit pathogenic organisms has been well recognized. Approaches to identify the microbiome associated with paper currency notes have been largely limited to culture dependent approaches. Subsequent studies portrayed the use of 16S ribosomal RNA based approaches which provided insights into the taxonomical distribution of the microbiome. However, recent techniques including shotgun sequencing provides resolution at gene level and enable estimation of their copy numbers in the metagenome. We investigated the microbiome of Indian paper currency notes using a shotgun metagenome sequencing approach. Metagenomic DNA isolated from samples of frequently circulated denominations of Indian currency notes were sequenced using Illumina Hiseq sequencer. Analysis of the data revealed presence of species belonging to both eukaryotic and prokaryotic genera. The taxonomic distribution at kingdom level revealed contigs mapping to eukaryota (70%), bacteria (9%), viruses and archae (~1%). We identified 78 pathogens including Staphylococcus aureus, Corynebacterium glutamicum, Enterococcus faecalis, and 75 cellulose degrading organisms including Acidothermus cellulolyticus, Cellulomonas flavigena and Ruminococcus albus. Additionally, 78 antibiotic resistance genes were identified and 18 of these were found in all the samples. Furthermore, six out of 78 pathogens harbored at least one of the 18 common antibiotic resistance genes. To the best of our knowledge, this is the first report of shotgun metagenome sequence dataset of paper currency notes, which can be useful for future applications including as bio-surveillance of exchangeable fomites for infectious agents.

Original Research Paper : PLOS ONE

Screening Currency Notes for Microbial Pathogens and Antibiotic Resistance Genes Using a Shotgun Metagenomic Approach


Using Bacterial Defense against Viruses


Xi Zhiyong
Xi Zhiyong


  This spring, a team of scientists has been driving around a small island in Guangzhou, southern China, releasing more than half a million mosquitoes from plastic pots on board trucks.

Rather than chasing the researchers away, families have welcomed their incursion: “Some residents have even asked to get mosquitoes from us to release in their own home,” said Xi Zhiyong of Michigan State University, who heads the project. The sight of the insects might set the skin crawling, but people know the alternative could be worse: this is one of several innovative attempts to tackle dengue fever by diluting the mosquito population with insects that don’t carry the disease.


The mosquito-borne sickness causes pain so agonizing it is also known as “breakbone disease” and last year saw China’s worst outbreak in two decades, with more than 47,000 cases, almost all in Guangdong province.

Catch one strain and you will be immune to the virus in future — but if bitten by a mosquito carrying another of the strains, you are more likely to develop severe dengue, also known as dengue hemorrhagic fever. No vaccine or treatment is available and recently it has caused about 22,000 deaths a year worldwide, mostly among children.

Before 1970, only nine countries had severe dengue epidemics; now it is endemic in more than 100 countries.

Yang Zhicong, deputy director of Guangzhou’s Center for Disease Control and Prevention, said authorities had hired anti-mosquito squads and quarantined dengue patients. Mr. Xi and his colleagues have released mosquitoes infected with Wolbachia bacteria, which make the males sterile and limit the insects’ ability to carry dengue.

Last year’s outbreak has helped persuade residents to embrace the pilot scheme, as has Mr. Xi’s willingness to plunge his hand into mosquito pots to prove that the males they are releasing do not bite. And while the Chinese government has not approved the release of genetically modified creatures, it accepted this trial because Wolbachia occurs naturally in many insects.

In the first phase, the team aims to reduce the mosquito population, as sterile males breed with wild females. In the second, Wolbachia infected females will be released to replace the wild, dengue-transmitting population, so mosquitoes from other areas face competition if they try to move in.

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