Conjugation of plasmid harboring bla NDM-1 in a clinical Providencia rettgeri strain through the formation of a fusion plasmid

has recently gained increased importance owing to the New Delhi metallo-β-lactamase (NDM) and other β-lactamases produced by its clinical isolates. These enzymes reduce the efficiency of antimicrobial therapy. Herein, we reported the findings of whole-genome sequence analysis and a comprehensive pan-genome analysis performed on a multidrug-resistant . 18004577 clinical strain recovered from the urine of a hospitalized patient in Shandong, China, in 2018. 18004577 was found to have a genome assembly size of 4.6 Mb with a G + C content of 41%; a circular plasmid p18004577_NDM of 273.3 Kb, harboring an accessory multidrug-resistant region; and a circular, stable IncT plasmid p18004577_Rts of 146.2 Kb. Additionally, various resistance genes were identified in its genome, including , , , ( ) , ( ) , ( ) , , , , ( ), and . Conjugation experiments and whole-genome sequencing revealed that the gene could be transferred to the transconjugant the formation of pJ18004577_NDM, a novel hybrid plasmid. Based on the genetic comparison, the main possible formation process for pJ18004577_ was the insertion of the [ ] ( ) translocatable unit module from p18004577_ into plasmid p18004577_Rts in the Russian doll insertion structure ( ), which played a role similar to that of using the "copy-in" route in the mobilization of [ ( ) ] . The array, multiplicity, and diversity of the resistance and virulence genes in this strain necessitate stringent infection control, antibiotic stewardship, and periodic resistance surveillance/monitoring policies to preempt further horizontal and vertical spread of the resistance genes. Roary analysis based on 30 . pan genome identified 415 core, 756 soft core, 5,744 shell, and 12,967 cloud genes, highlighting the "close" nature of . pan-genome. After a comprehensive pan-genome analysis, representative biological information was revealed that included phylogenetic distances, presence or absence of genes across the . bacteria clade, and functional distribution of proteins. Moreover, pan-genome analysis has been shown to be an effective approach to better understand . bacteria because it helps develop various tailored therapeutic strategies based on their biological similarities and differences.