Bacterial contamination of Pakistani currency notes from hospital and community sources

Objective: We determined the bacterial contamination and antibiotic resistance profile of circulating Pakistani currency notes collected from hospital and community sources.

Methods: This prospective study was organized from July to December 2015 in the Microbiology Department of The Children’s Hospital and The Institute of Child Health Lahore. It was done on one hundred currency notes of four different denominations collected from various groups of people in sterile polythene bags. Gram staining, colony morphology and various biochemical tests were used to identify the bacterial isolates. Kirby Bauer disc diffusion method was used to observe the antibacterial drug resistance.

Results: There were 11 different types of bacterial species which contaminated 97 (97%) currency notes. The bacterial isolates discovered from paper currency notes included Klebsiella spp. (26.0%), Coagulase-negative Staphylococci (CoNS) (18.3%), E. coli (14.5%), Pseudomonas spp. (13.7%), Citrobacter spp. (11.5%), Enterobacter spp. (5.3%), Acinetobacter spp. (5.3%), Streptococcus spp. (2.3%), Shigella spp. (1.5%), Salmonella spp. (0.8%) and Pantoea spp. (0.8%). Most of the Gram-positive isolates were resistant to penicillin and ampicillin. None of the Gram-negative isolates found to be resistant to amikacin, cefoperazone-sulbactam and piperacillin-tazobactam.

Conclusion: The currency notes circulating in hospital and community are contaminated with highly pathogenic and some multi-drug resistant bacteria. These currency notes could be a potential source of nosocomial and community-acquired infections.