Knowledge, Attitudes, and Practices of the Saudi Arabian Population Regarding Contaminated Banknotes: Implications for Infectious Disease Transmission and Analyzing the Biofilm in Wallet as a Reservoir

<b>Introduction:</b> Contaminated paper currency may serve as a potential source for multidrug-resistant pathogens, posing risks not only to individuals who handle cash but also to public health. This study aimed to evaluate the knowledge, attitudes, and practices (KAP), and microbial contamination of paper currency and biofilm formation in the wallet as a reservoir of contamination in Saudi Arabia (KSA). <b>Methods:</b> Data were collected through an online survey assessing the KAP of the Saudi population regarding the use of contaminated notes across various provinces from February to April 2018. The analysis was conducted using EPI INFO V7 software. Microorganisms were isolated and identified from paper and plastic currency collected from slaughterhouses, gas stations, and hospital cafeterias. The MicroScan WalkAway system was utilized for confirmation and antimicrobial resistance (AMR) testing, while scanning electron microscopy (SEM) was employed to visualize biofilms present in wallets. <b>Results:</b> Among the 1415 adult Saudi citizens surveyed, 75% lacked awareness about contaminated currency. Over 50% reported not washing their hands after handling contaminated notes, with 78% of those being male. Fifteen different microbial species were isolated from contaminated notes, including <i>Staphylococcus</i> and fecal coliforms. Multidrug-resistant <i>Staphylococcus</i> and <i>Enterobacter</i> were detected in nearly all paper notes, while extended-spectrum beta-lactamase (ESBL) <i>E</i>. <i>coli</i> was found only in 50-riyal notes. Plastic notes showed no bacterial contamination. SEM images of the interior surfaces of wallets revealed the presence of extracellular polymeric substances (EPSs) in biofilms, along with cocci-shaped bacteria. <b>Conclusion:</b> To mitigate health risks, it is recommended that paper notes be replaced with plastic currency, and efforts should be made to raise awareness among the Saudi population regarding the dangers posed by contaminated notes.