BIOSURVEILLANCE USING PAPER CURRENCY AS A FOMITE AND CHANGES IN THE BACTERIAL COMMUNITY OVER TIME

There are different methods to monitor the health of the community and the movement of pathogens. In our Microbiology Laboratory classes we have had students bring in dollar bills (paper currency) and had them expose one quarter of the bill to a plate of Nutrient Agar, another quarter to Mannitol Salt Agar, and a third to Eosin Methylene Blue Agar. Numbers of bacteria, CFU’s (colony forming units), ranged from several hundred per bill to thousands for those sampled during warm days in the autumn. The MSA plates with their high salt content are selective for Staphylococcus sp. So Mannitol fermenting-gram positive cocci, bacteria were presumed to be Staphylococcus aureus (Sa) and were used to test for antibiotic resistance in our community. For example, Penicillin resistance was monitored for three years in a row. During the school term Spring 11, 9/12 (75%) samples were penicillin resistant, Spring 12, 22/24 (91%) were penicillin resistant but in Spring13 only 14/30 (43%) were penicillin resistant. When the penicillin resistant Sa was further analyzed on ChroMRSA plates many of these bacteria have been MRSA. However during Spring 13 only 3/14 (21%) were MRSA. The presence of MRSA in both hospital and community settings has been alarming this data suggests that public health efforts are starting to have an effect on the number of the MRSA bacteria carried by money in the Columbia SC area (hospitals report fewer MRSA HAI’s recently). Enteric bacteria were low in most sampling periods, but high during hot weather. Many different patterns of bacterial contamination have been found.

The potential ease of currency sampling as a means of BioSurveillance makes it a method with great potential for both monitoring and predicting disease patterns. The use of paper currency to introduce pathogens into American communities or military bases (ships) is a potential concern, and sampling may detect either deliberate or accidental pathogen carriage. It also provides a quick method to determine the antibiotic resistance patterns of pathogens in a community and may provide treatment guidance. Understanding the community patterns of carriage and their changes through time help allow recognition and possibly prevention of pathogen outbreaks.