Plasmids of two novel incompatibility groups IncFIIpPROV114-NR and IncpCHS4.1-3 from Providencia.

This study presents the genetic structure of two incompatibility (Inc) groups found in Providencia: the newly discovered IncFII_pPROV114-NR and the newly designated Inc_pCHS4.1-3. An extensive genomic comparison was performed on all 14 plasmids (three IncFII_pPROV114-NR plasmids and 11 Inc_pCHS4.1-3 plasmids) from Providencia, including 12 newly sequenced in this study and two from GenBank. Three IncFII_pPROV114-NR plasmids had similar conserved backbones but differed in accessory modules. The 11 Inc_pCHS4.1-3 plasmids fell into two groups according to differences in the conserved genes of the plasmid backbone. The accessory modules of 11 Inc_pCHS4.1-3 plasmids showed significant diversity, indicating numerous gene gains and losses, including in the Tn1696-related region, in Tn7504, in a 17.3-kb sul2 region, and a 63.6-kb bla_NDM-1 region. A minimum of 45 obtained antimicrobial resistance genes (ARGs) were identified in 13 of the 14 plasmids, covering resistance to 14 classes of antimicrobials and heavy metals. Five new mobile genetic elements (MGEs) were identified, including In2168, In1790, Tn7500, Tn7501, and Tn7502. Additionally, three MGEs, Tn7499, Tn7503, and Tn7504 were newly designated. These two Inc group plasmids integrate abundant accessory modules that allow them to accumulate and distribute ARGs and improve the survivability of Providencia under the pressure of drug selection.