Dirty money isn’t just an expression; this study reports antibiotic resistant Staphylococcus aureus in euro currency.
Investigation into the prevalence, persistence and antibiotic resistance profiles of staphylococci isolated from euro currency
The study set out to sample €10 banknotes for the presence of coagulase-positive staphylococci (CPS) such as Staphylococcus aureus (S. aureus) and coagulase-negative staphylococci (CoNS) in Southern Ireland, to assess the levels of antibiotic resistance among those isolated, and determine the persistence of S. aureus on €10 banknotes and €2 coins.
Methods and Results
We report that 97% of €10 banknotes screened (n=155) harboured multiple species of staphylococci. From the generated bank of strains a total of 150 representative staphylococci isolates were used for further study, 71 were CPS and 79 were CoNS. Of these, we found that 62% of the staphylococci demonstrated resistance to at least one of the 1st line antibiotics (52.11% of CPS isolates and 76.71% of the CoNS isolates). Resistance to multiple antibiotics was seen in 31.18% of the resistant isolates. In relation to persistence studies, S. aureus was shown to remain viable on euro banknotes and coins for significant periods (on average, 19.33 days on €10 banknotes, and 16.67 days on €2 coins) as determined using bioluminescence.
We advocate the expansion of antibiotic surveillance programs, with a view to tracking/monitoring antibiotic resistance dissemination among environmental contaminants. Additionally we propose that “cashless transactions” should be encouraged in high risk environments such as hospitals and health care settings, as well as stricter infection controls.
Significance and impact of study
Although it is accepted that circulating currency has the potential to harbour disease-causing pathogens, studies investigating prevalence and persistence of such pathogens on euro currency are virtually non-existent. In an attempt to rectify this, we examined the prevalence of staphylococci on €10 banknotes in Ireland and report relatively high levels of antibiotic resistance amongst the isolates. Furthermore, we have established the persistence of S. aureus on euro currency for the first time.