Emergence of Extensively Drug-Resistant Proteus mirabilis Harboring a Conjugative NDM-1 Plasmid and a Novel Salmonella Genomic Island 1 Variant, SGI1-Z

Acquisition of blaNDM-1 in bacterial species, such as Proteus mirabilis that is intrinsically resistant to tetracycline, tigecycline and colistin, will make clinical treatment extremely difficult. Here, we characterized an NDM-1-producing clinical isolate of P. mirabilis (PM58) that displayed an extensively drug-resistant (XDR) phenotype, susceptible only to aztreonam. Molecular analysis revealed that PM58 harbored both a conjugative NDM-1 plasmid and a novel Salmonella genomic island 1 variant on chromosome.