Bacterial Contamination of Paper Banknotes in Circulation; a Case Study in the Jenin District, Palestine

Paper banknotes in circulation were collected from the Jenin city and examined for bacterial contamination. The colony forming units (CFU/ml) of sterile water used in washing each banknote ranged between 4.6 x 104 and 9.7 x 105. The major contaminating bacterial species was Escherichia coli (71%), which is an opportunistic human pathogen. The other species including Staphylococcus aureus (9%), Proteus (8%), Bacillus (4%), Shigella (3%), Salmonella (3%), and Klebsiella (2%), were believed to be causative agents of human diseases. Bacterial contamination depended on the denomination of the banknotes. Lower denominations were more contaminated than higher ones. A higher bacterial count was recorded on dirty and tattered banknotes compared with clean and new ones. This study has demonstrated that local banknotes could be a potential source of contamination by bacterial pathogens.