ResearchBlogging.orgFirst up, a disclaimer. I know one of the researchers who conducted this short study personally and professionally. I admire their work and what they have done to further the cause of promoting research by medical students in India. So, this post may be a little biased, but anyways, I decided to go ahead with it because it is a very interesting topic.

This post was chosen as an Editor's Selection for ResearchBlogging.org
Studies have shown that currency notes are prone to get tainted with illicit drugs (1) like cocaine, heroine and amphetamines. This time around, the researchers decided to look for bugs on bucks. The interesting bit would be how they managed to collect the coins.

Twenty-five samples each of currency notes and coins were collected from the general population by following simple random sampling technique. The study population included people from various occupations and walks of life, like beggars (n = 6), street food vendors (n = 11) and school children (n = 8). The samples were collected in a sterilized paper packet, numbered serially and transported to the laboratory for microbial screening.

I have some problems with this form of collection.

  1. The coins were collected from a very non representative sample. There should have been more sources, preferably some from within an hospital environment or from adjacent places in a hospital. It would skew the results, agreed, but then again, this is an important source of the colonization anyways.
  2. I do not see any table noting what denomination of currency notes/coins were involved. That table would in itself be an interesting read. Are notes of bigger denominations more/less likely to carry bugs than coins and notes of lower denominations? What might have been the implications of those findings?
  3. Another question which should have been addressed is how long were the notes/coins in circulation? Whilst admittedly, this may be difficult to answer, the key lies in the fact that the longer a piece is in circulation.more likely it is to have picked up some bugs. I guess this is one bias which the authors have not addressed.

And as far as finding bugs in bucks is concerned, the authors note:

A total of 50 samples were examined, which consisted of 25 coins and currency notes each. Among the currency screened, 10 coins and 15 notes showed growth of single bacterial species, 11 coins and 9 notes showed the growth of two types of bacterial species each, and three coins and one note had grown three different organisms. The common fungal isolate from two of the coins was Aspergillus niger (n = 2). The bacterial isolates include Staphylococcus aureus (n = 11), Klebsiella spp. (n = 6), Escherichia coli (n = 01), Staphylococcus epidermidis (n = 3), Citrobacter spp. (n = 7), Pseudomonas spp. (n = 4), Acinetobacter spp. (n = 4), Enterobacter agglomerans (n = 2), Micrococcus spp. (n = 1), α – haemolytic Streptococcus spp. (n = 1) and Bacillus spp. (n = 35).

We have observed that 96% of the coins and 100% of the currency notes were found to be contaminated with different bacterial species, of which S. aureus, Klebsiella spp. and E. coli can be considered as pathogens, as they have been implicated in various diseases. The other isolates being ubiquitous environmental organisms rarely cause disease in healthy hosts, but have been reported to cause serious nosocomial infections in immunocompromised individuals

That is one LONG list of bugs. And kinda scary too. And when you factor in the issue that they also showed considerable amount of drug resistance, it becomes a potential threat to public health. Also, it goes to show what the range of antibiotic resistance at the community level is like.



Click on the images to view a bigger version.


Admittedly, this is more like a proof of concept study than anything else, but it throws up several interesting questions, which makes it a nice bit of research work. Besides the fact that a more detailed study with larger number of currency denominations, culled from a more representative population would be in order to validate the findings of this study, there is one question which pokes me no ends:

What are the chances of infected currency passing on a bug to a healthy/ill person? This would actually be an important study in that it would potentially evaluate the role of currency as an agent of bioterrorism. Imagine, how poetic it is that the very currency people figuratively die to hoard would literally be the death of them. Oh how true were the sages when they said money is the root of all evil!

Imagine how insecure one would feel with the background knowledge that a terrorist outfit may have sprinkled anthrax spores or ebola virus particles or whatever on out notes? One step to not only spread death, disease and destruction, but also bring down the rather fragile economies as well! Talk about two birds with one stone!

Anyways. Moving away from the deadly musings, I would like to congratulate Akshay for coming up with this innovative topic. He has made it into the pantheons of published medical students and I cannot think of another person who is more deserving of this honor than him. If you are into reading eclectic medical blogs, then you might consider heading over to Akshay’s blog to read up on his take on a number of social, medical and personal issues.

P.S.: Will you now be reaching for the hand sanitizers after handling money? How inconvenient would THAT make your life?


1. Oyler, J., Darwin, W. D. and Cone, E. J., J. Anal. Toxicol., 1996, 20, 213–216.



Article in Focus:

Sharma A, Dhanashree B (2011). Screening of currency in circulation for bacterial contamination. Current Science, 100 (6), 822-825

5 thoughts on “Buck-teria!

  1. Agree on all counts with respect to the paper. It was more of a preliminary study since there were none from India previously on this topic. But now that we know how bad the situation is, I am sure this would pave the way for further studies answering all these questions.

    As far as the comments about me go, thank you thank you.. 😀


    1. Well, you have always been a person I admired a lot. And the study looks nice, considering the fact that you did it all in just 2 months’ time!


  2. This is certainly a very interesting study, and even I agree that it could be more detailed. We call something like this a pilot study, and can be followed by a more detailed and full research based on the conclusions…

    p.s. am surprised that this study wasn’t done earlier…


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