Bacterial contamination of Saudi "one" Riyal paper notes

Fomites are inanimate objects that are capable of absorbing, harboring and transmitting infectious microorganisms. Paper currency, an exchangeable fomite, is constantly subjected to contamination. This study investigated bacterial contamination on the Saudi one Riyal paper note. Two hundred one Riyal bills (100 4th version and 100 5th version) were collected in the city of Jeddah for examination. The notes were examined for bacterial contamination using blood agar and MacConkey agar. Eighty-eight percent of the notes were contaminated with mixed (>or=2 types) bacterial growth. All 4th version notes had mixed bacterial growth: gram-positive bacilli (79%), coagulase-negative staphylococci (75%), Staphylococcus aureus (38%), Klebsiella spp (21%), Pseudomonas spp (19%), Escherichia coli (9%), viridans group streptococci (VGS) (8%), and non-hemolytic streptococci (4%). Seventy-six percent of the newer 5th version notes had mixed bacterial growth: gram-positive bacilli (68%), coagulase-negative staphylococci (64%), S. aureus (13%), Klebsiella spp (9%), Pseudomonas spp (5%), E. coli (2%) and VGS (2%). These results indicate the Saudi one Riyal paper note is commonly contaminated with bacteria, and may act as a vehicle for the transmission of potentially pathogenic bacteria. The more the bill had been handled the greater the contamination was.