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Filthy lucre: A metagenomic pilot study of microbes found on circulating currency in New York City

View Article: PubMed Central - PubMed

ABSTRACT

Background: Paper currency by its very nature is frequently transferred from one person to another and represents an important medium for human contact with—and potential exchange of—microbes. In this pilot study, we swabbed circulating $1 bills obtained from a New York City bank in February (Winter) and June (Summer) 2013 and used shotgun metagenomic sequencing to profile the communities found on their surface. Using basic culture conditions, we also tested whether viable microbes could be recovered from bills.

Results: Shotgun metagenomics identified eukaryotes as the most abundant sequences on money, followed by bacteria, viruses and archaea. Eukaryotic assemblages were dominated by human, other metazoan and fungal taxa. The currency investigated harbored a diverse microbial population that was dominated by human skin and oral commensals, including Propionibacterium acnes, Staphylococcus epidermidis and Micrococcus luteus. Other taxa detected not associated with humans included Lactococcus lactis and Streptococcus thermophilus, microbes typically associated with dairy production and fermentation. Culturing results indicated that viable microbes can be isolated from paper currency.

Conclusions: We conducted the first metagenomic characterization of the surface of paper money in the United States, establishing a baseline for microbes found on $1 bills circulating in New York City. Our results suggest that money amalgamates DNA from sources inhabiting the human microbiome, food, and other environmental inputs, some of which can be recovered as viable organisms. These monetary communities may be maintained through contact with human skin, and DNA obtained from money may provide a record of human behavior and health. Understanding these microbial profiles is especially relevant to public health as money could potentially mediate interpersonal transfer of microbes.

No MeSH data available.


Differences in the abundance of organisms identified on $1 bills collected in Winter vs. Summer 2013.(A) Proportion of human matches identified by megaBLAST-LCA for each time point. (B) Proportional distribution of non-human megaBLAST-LCA results. Low quality matches are defined as those filtered out prior to LCA analysis (see Materials and methods). High quality BLAST matches are broken down by taxonomic category and only categories with proportions >1% are included.
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pone.0175527.g003: Differences in the abundance of organisms identified on $1 bills collected in Winter vs. Summer 2013.(A) Proportion of human matches identified by megaBLAST-LCA for each time point. (B) Proportional distribution of non-human megaBLAST-LCA results. Low quality matches are defined as those filtered out prior to LCA analysis (see Materials and methods). High quality BLAST matches are broken down by taxonomic category and only categories with proportions >1% are included.

Mentions: To sample monetary microbiome diversity over time, we collected an additional set of twenty $1 bills from the same bank in June 2013. DNA from these bills was pooled into one sample for library preparation and subjected to shotgun metagenomic sequencing, generating 476,898,204 reads. Both the February and June 2013 read sets (referred to henceforth as Winter and Summer) contain matches to prokaryotes, eukaryotes, archaea, and viruses. In both sets the number of archaeal and viral sequences detected was low (< 1%), and were not analyzed further. Human sequences were the most abundant in the Winter data (56.4%), but were much less abundant in the Summer data (39%) (Fig 3A). At both time points eukaryotes represent the largest portion of non-human reads, albeit much smaller in Winter (41.2%) than Summer (67.4%; Fig 3B). Metazoan BLAST matches were the dominant group in Summer, with top hits to Equus caballus (horse, 49%), followed by Sus scrofa (wild boar, 6%), and Canus lupis (grey wolf, 2%). Although these are the top-ranking BLAST hits, Sus scrofa and Canus lupis are likely artifacts of Genbank and represent the presence of other eukaryotic genomes that are more prevalent in an urban environment (e.g. dogs and domestic pigs). Equus caballus was also the most abundant taxon in Winter (3.5%) followed two fungal species Aspergillus niger (1%) and Wallemia sebi (1%), both of which are commonly found in indoor environments, and associated with contaminated food [28–30]. For bacterial reads the opposite was true, with Winter bills yielding a higher proportion than Summer (Fig 3B).


Filthy lucre: A metagenomic pilot study of microbes found on circulating currency in New York City
Differences in the abundance of organisms identified on $1 bills collected in Winter vs. Summer 2013.(A) Proportion of human matches identified by megaBLAST-LCA for each time point. (B) Proportional distribution of non-human megaBLAST-LCA results. Low quality matches are defined as those filtered out prior to LCA analysis (see Materials and methods). High quality BLAST matches are broken down by taxonomic category and only categories with proportions >1% are included.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5383295&req=5

pone.0175527.g003: Differences in the abundance of organisms identified on $1 bills collected in Winter vs. Summer 2013.(A) Proportion of human matches identified by megaBLAST-LCA for each time point. (B) Proportional distribution of non-human megaBLAST-LCA results. Low quality matches are defined as those filtered out prior to LCA analysis (see Materials and methods). High quality BLAST matches are broken down by taxonomic category and only categories with proportions >1% are included.
Mentions: To sample monetary microbiome diversity over time, we collected an additional set of twenty $1 bills from the same bank in June 2013. DNA from these bills was pooled into one sample for library preparation and subjected to shotgun metagenomic sequencing, generating 476,898,204 reads. Both the February and June 2013 read sets (referred to henceforth as Winter and Summer) contain matches to prokaryotes, eukaryotes, archaea, and viruses. In both sets the number of archaeal and viral sequences detected was low (< 1%), and were not analyzed further. Human sequences were the most abundant in the Winter data (56.4%), but were much less abundant in the Summer data (39%) (Fig 3A). At both time points eukaryotes represent the largest portion of non-human reads, albeit much smaller in Winter (41.2%) than Summer (67.4%; Fig 3B). Metazoan BLAST matches were the dominant group in Summer, with top hits to Equus caballus (horse, 49%), followed by Sus scrofa (wild boar, 6%), and Canus lupis (grey wolf, 2%). Although these are the top-ranking BLAST hits, Sus scrofa and Canus lupis are likely artifacts of Genbank and represent the presence of other eukaryotic genomes that are more prevalent in an urban environment (e.g. dogs and domestic pigs). Equus caballus was also the most abundant taxon in Winter (3.5%) followed two fungal species Aspergillus niger (1%) and Wallemia sebi (1%), both of which are commonly found in indoor environments, and associated with contaminated food [28–30]. For bacterial reads the opposite was true, with Winter bills yielding a higher proportion than Summer (Fig 3B).

View Article: PubMed Central - PubMed

ABSTRACT

Background: Paper currency by its very nature is frequently transferred from one person to another and represents an important medium for human contact with&mdash;and potential exchange of&mdash;microbes. In this pilot study, we swabbed circulating $1 bills obtained from a New York City bank in February (Winter) and June (Summer) 2013 and used shotgun metagenomic sequencing to profile the communities found on their surface. Using basic culture conditions, we also tested whether viable microbes could be recovered from bills.

Results: Shotgun metagenomics identified eukaryotes as the most abundant sequences on money, followed by bacteria, viruses and archaea. Eukaryotic assemblages were dominated by human, other metazoan and fungal taxa. The currency investigated harbored a diverse microbial population that was dominated by human skin and oral commensals, including Propionibacterium acnes, Staphylococcus epidermidis and Micrococcus luteus. Other taxa detected not associated with humans included Lactococcus lactis and Streptococcus thermophilus, microbes typically associated with dairy production and fermentation. Culturing results indicated that viable microbes can be isolated from paper currency.

Conclusions: We conducted the first metagenomic characterization of the surface of paper money in the United States, establishing a baseline for microbes found on $1 bills circulating in New York City. Our results suggest that money amalgamates DNA from sources inhabiting the human microbiome, food, and other environmental inputs, some of which can be recovered as viable organisms. These monetary communities may be maintained through contact with human skin, and DNA obtained from money may provide a record of human behavior and health. Understanding these microbial profiles is especially relevant to public health as money could potentially mediate interpersonal transfer of microbes.

No MeSH data available.