Multidrug-resistant Opportunistic and Pathogenic Bacteria Contaminate Algerian Banknotes Currency

Abstract

Currency is one of the most exchanged items in human communities as it is used daily in exchange for goods and services. It is handled by persons with different hygiene standards and can transit in different environments. Hence, money can constitute a reservoir for different types of human pathogens. This study aimed to evaluate the potential of Algerian banknotes to shelter opportunistic pathogenic and multiresistant bacteria. To that end, 200 circulating notes of four different denominations were collected from various places and analyzed for their bacterial loads and contents. Besides, predominant strains were identified and characterized by biochemical and molecular methods, and their resistance profiles against 34 antibiotics were determined. Our results indicated that 100% of the studied banknotes were contaminated with bacteria. The total bacterial concentrations were relatively high, and different bacterial groups were grown, showing important diversity. In total, 48 predominant strains were identified as belonging to 17 genera. Staphylococcus and Micrococcus were the most prevalent genera, followed by Bacillus, Pseudomonas, and Acinetobacter. Antibiotic susceptibility testing showed that all the isolates harbored resistance to at least two molecules, and worrying resistance levels were observed. These findings prove that Algerian currency harbors opportunistic multiresistant bacteria and could potentially act as a vehicle for the spread of bacterial diseases and as a reservoir for antibiotic resistance genes among the community. Therefore, no cash payment systems should be developed and generalized to minimize cash handling and subsequent potential health risks.

Keywords: Algeria; antibiotic resistance; circulating resistance genes; currency; opportunistic bacteria.

Fig. 1.

Phylogenetic relationships between strains isolated from Algerian banknotes and reference bacterial strains using 16S rRNA sequences: (a) Gram-positive strains; (b): Gram-negative strains. The evolutionary distances were computed using the Tamura-Nei method and are in the units of the number of base substitutions per site. The phylogenetic trees were constructed using the Neighbor-joining algorithm. Bootstrap values (1,000 replicates) are indicated at the nodes.

Fig. 1.

Phylogenetic relationships between strains isolated from Algerian banknotes and reference bacterial strains using 16S rRNA sequences: (a) Gram-positive strains; (b): Gram-negative strains. The evolutionary distances were computed using the Tamura-Nei method and are in the units of the number of base substitutions per site. The phylogenetic trees were constructed using the Neighbor-joining algorithm. Bootstrap values (1,000 replicates) are indicated at the nodes.