Assessment of microbial contamination of indian currency notes in circulation – An In vitro study

Abstract

Background: Currency notes represent a universal medium for transmission of bacteria in the environment and among humans. Care should be taken by those handling these currencies. Aim: To quantitatively assess and compare the total bacterial load of Staphylococcus aureus, Escherichia coli, and Proteus species present on the currency notes circulating in the open market area and hospitals in Mangalore city. Methodology: A total of 24 frequently circulated currency notes were collected from open markets and hospitals (12 from each group). They were then deposited in sterile pouches. Samples were collected using moistened cotton swabs and inoculated onto MacConkey agar for bacterial growth. The isolated bacteria were then assessed for the percentage of bacteria and colony-forming units (CFUs) on the notes using standardized microbial analysis. Results: Cultures after microbial analysis showed bacterial contamination with S. aureus, E. coli, Klebsiella, and aerobic spore-bearing bacteria. Approximately >103 CFUs/plate were found. In the hospital group, isolated organisms comprised S. aureus (54%) and E. coli(25%); in the open market areas, E. coli(36%) and S. aureus (38%) were found. Proteus species were not present on any of the samples. Intergroup statistical analysis carried out using the Chi-square test was statistically significant (P = 0.034). Conclusion: The study concluded that the notes from hospitals were contaminated more with S.aureus than in open markets, whereas E. coli was found to be more in open market areas than in hospitals.

Keywords

• bacterial contamination
• escherichia coli
• indian paper currency
• pathogens
• staphylococcus aureus