Assessment of Microbial Contamination and Antibiotic Resistance Profiles of Bacteria on Nigerian Currency Notes: Implications for Public Health and Antimicrobial Resistance

Background: Many microbes have been associated with the contamination of Naira notes, and most of these microbes have shown high resistance to antimicrobials, with different resistance profiles including multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR). Therefore, the aim of this study was to investigate the microbial contamination and antibiotic resistance profiles of isolated microorganisms on Nigerian currency notes, emphasizing their public health implications. Methods: A total of 112 currency notes, spanning all eight denominations, were collected from rural (Oyan) and urban (Osogbo) regions in Osun State, Nigeria. Microbial isolation and identification were performed using standard culture techniques, while antibiotic susceptibility was assessed via the Kirby-Bauer disc diffusion method. Data were analyzed using SPSS. Results: Microbial analysis revealed high contamination rates, with Klebsiella sp (35.7% rural, 23.2% urban) and Staphylococcus aureus (28.6% rural, 26.8% urban) being the most prevalent bacterial isolates. Aspergillus sp was the dominant fungal contaminant, particularly in rural areas. Polymer-based notes exhibited lower contamination compared to paper-based notes. Antibiotic susceptibility tests highlighted alarming multidrug resistance (MDR), with Staphylococcus aureus showing high resistance to Penicillins and Cephalosporins. Pseudomonas aeruginosa displayed extensive drug resistance (XDR) to multiple antibiotic classes, leaving limited treatment options. Conclusion: Nigerian currency notes are significant reservoirs of microbial contamination and multidrug-resistant pathogens, posing severe public health risks. The study underscores the need for improved hygiene practices, public awareness campaigns, and a transition to polymer-based notes. Strengthened antibiotic stewardship programs and regulatory measures are essential to combat rising antimicrobial resistance and prevent pathogen dissemination through currency handling.