A study of Bacterial Contamination of Ghanaian Currency Notes in Circulation

The study aimed at determining the presence, type and nature of bacterial contamination of Ghanaian currency notes in circulation. One hundred currency notes of different denominations were randomly collected from sellers on the major streets and markets of the Cape Coast Metropolis into sterile paper bags, shaken in universal bottles with 10ml sterile buffered peptone water, removed and the resulting peptone water incubated overnight and later sub-cultured onto Blood agar, MacConkey, Cysteine Lactose Electrolyte Deficient (CLED) and incubated at 37 0 C for 24hours. Colonial Morphology, Gram Reactions and Biochemical tests were used for identification of isolates. All 100 samples collected were contaminated with one or more bacteria representing 100% contamination. A total of 107 bacteria isolates were obtained from the 100 samples made up of 13 different bacteria species. Bacteria isolated from the notes include Coagulase negative Staphylococci (23.4%), Staphylococci aureus (8.4%), Escherichia coli(5.6%), Bacillus species (23.4%), Klebsiella species (5.6%), Enterobacter species (2.8%), Enterococci species (10.3%), and Proteus species (8.4%) among others. The One Ghana Cedi and Twenty Ghana Cedi notes had more bacteria isolated than their number sampled (43 out of 40) and (25 out of 20) respectively. Although the number of species isolated increased with sample numbers, all the denominations were contaminated with Coagulase Negative Staphylococci and Bacillus species. Four non-circulated notes of each denomination used as controls had no bacteria growth. This work seeks to confirm bacterial contamination of everyday currency and also introduces the nature and levels of contamination of the Ghanaian currency. Introduction The possibility that currency notes might act as environmental vehicles or formites for the transmission of potential microorganism was suggested in the 1970s (Abrams & Waterman, 1972). The use of paper currency for every type of commerce is hard on the currency, with the lower-denomination notes receiving the most handling because they are exchanged frequently (Gadsby, 1998; Ogbu and Uneke, 2007). These means money which may get contaminated during production, storage, after production, and during use are always in circulation (Hugo et al., 1983). Confirmation of contamination of money by drugs has been detected in the United States and United Kingdom (Ritter, 1997; Jenkins, 2001, Thompson, 2002). Contamination from the skin, anal region, wounds, nasal secretions and aerosols generated by sneezing and coughing are potential sources of transfer of microorganisms to currency notes during handling (Mackintosh and Hoffman, 1984). Numerous research on currency in several countries indicated bacterial contamination. A study by Hosen et al., (2002) in Bangladesh revealed coliform contamination of 80% of thirty old two-taka notes, Pope et al., 2002, isolated pathogenic or potentially pathogenic organisms from 94% of one-dollar bills, Basavarajappa et al., (2005) found 96 out of 100 currencies contaminated with bacteria (K. pneumoniae, E. coli, S. aureus, Pseudomonas species and S. Typhi), fungal and protozoa and Umeh et al., in 2007, revealed that 89.8% of Nigerian currency notes in circulation within the University of Agriculture, Makurdi Campus has microbial contamination. The Ghanaian currency like any other being used in the world is exposed to the potential of bacterial contamination. Thus this present study seeks to introduce the nature, type and level of contamination of the Ghanaian currency in circulation. Material and Methods Samples and Sampling: The study samples were collected based on the level of usage and thus circulation. This was made up of 40 One Ghana Cedi notes (GH¢ 1), 25 Five Ghana Cedi notes (GH¢ 5), 20 Ten Ghana Cedi notes (GH¢ 10), 10 Twenty Ghana Cedi (GH¢ 20) notes and 5 Fifty Ghana Cedi notes (GH¢ 50) collected randomly from sellers on the major streets and markets of the Cape Coast Metropolis into sterile paper bags between September, 2009 to March, 2010 and transported to the Laboratory of the Department of Laboratory Technology, University of Cape Coast for bacteriological analysis on the same day. Four currency notes of each denomination and not in circulation obtained from the Central Bank were used as control samples. Culture and Isolation of Bacteria: Each currency note was aseptically transferred into individual universal bottles containing 10 ml of sterile buffered peptone water and the bottle vigorously shaken for 2 minutes. The currency is removed and the resulting peptone water solution served as a test sample and incubated for 24hours at of 37 o C. The incubated test sample was then cultured onto Blood agar, MacConkey and Cysteine Lactose Electrolyte Deficient (CLED). The plates were incubated aerobically overnight in an incubator at 37 0 C. Pure cultures were obtained by sub-culturing distinct colonies. Control samples underwent the same processes. Identification of Isolates: Pure isolated colonies were identified using their Morphology, Gram reaction as well as biochemical techniques such as the Indole Catalase, Coagulase, Oxidase, Urease, Catalase test and Triple sugar iron tests (sugar fermentation and gas production). Statistical Analysis: Data from study was analyzed descriptively using SPSS 16.0 software. Results All 100 samples analysed were contaminated with various species of bacterial representing 100% contamination (Table: 1). A total of 107 bacterial isolates were obtained from the 100 samples analysed whilst all 20 samples not in circulation were negative for any bacterial isolate. Bacteria isolated from the notes were Coagulase Negative Staphylococci (23.4%), Staphylococci aureus (8.4%), β-hemolytic Streptococci (3.7%), αhemolytic Streptococci(3.7%), E. coli (5.6%), Yersinia species (2.8%), Bacillus species (23.4%), Klebsiella species (5.6%), Shigella species(0.9%), Enterobacter species (2.8%), Enterococci species (10.3%), Listeria monocytogenes (0.9%) and Proteus species (8.4%), (Table: 1). Coagulase Negative Staphylococci and Bacillus species were both the highest isolates and also present on all the currency whilst Listeria Monocytogenes and Shigella species were the least isolated (Table: 2) being isolated one time each on different currencies.