Abstract
Background: The presence of pathogenic bacteria in circulated currency was recorded as a public health hazard. In this study, all examined Sudanese banknotes (100%) were found to be contaminated by gram-negative bacteria. Proteus mirabilis were recovered from 10 examined notes (22.2%, f = 10), E. coli (13.3%, f = 6) and Klebsiella spp. (8.9%, f = 4) were also identified. Only the most resistant P. mirabilis isolate was identified using culture-based and 16S rRNA gene sequencing techniques. Methods: Proteus isolates were identified phenotypically and tested for their susceptibility to 16 of commonly used antibiotics, then most resistant isolate was confirmed genotypically via 16S rRNA gene amplification and sequencing. Bioinformatics analysis using BLAST for sequence similarity search, Clustal W program for multiple sequence alignment, MEGA7 software for phylogenetic analysis. Tree was constructed to show the evolutionary relationships of the obtained sequence with similar sequences in the databases using. Results: The obtained sequence was found to be 100% identical to P. mirabilis 16S rRNA gene using BLAST. The phylogenetic tree was constructed to show the evolutionary relationships of the obtained sequence with similar sequences in the databases using MEGA7 software, and the closest strain was found to be P. mirabilis strain from India (EU411047). Conclusion: This study has shown that some currency notes circulated at Khartoum transportation are carriers of antimicrobial-resistant P. mirabilis that could be potential source for their transmission in public.