Characterization of pUO-StVR2, a virulence-resistance plasmid evolved from the pSLT virulence plasmid of Salmonella enterica serovar Typhimurium

Abstract

pUO-StVR2 is a virulence-resistance plasmid which originated from pSLT of Salmonella enterica serovar Typhimurium through acquisition of a complex resistance island, flanked by regions that provide a toxin-antitoxin system and an iron uptake system. The presence of resistance and virulence determinants on the same plasmid allows coselection of both properties, potentially increasing health risks.

FIG. 1.

Relationship between pSLT and pUO-StVR2. (A) Restriction analysis of pSLT and pUO-StVR2. (B) Hybridization with the entire pSLT plasmid. Ba, BamHI; E, EcoRI; H, HindIII; P, PstI; S, SalI; Sp, SphI; λ, DNA of phage lambda digested with PstI, used as a size standard; lanes 1 and 2, pSLT and pUO-StVR2, respectively.

FIG. 2.

(A) Schematic representation of the DNA acquired by pSLT to compose pUO-StVR2. Solid and dashed horizontal lines above the scheme are used to point out the distinct components of the represented DNA. Plasmids showing the highest similarity to the main regions are indicated in parentheses. (B) pSLT region where the foreign DNA was inserted (based on accession no. AE006471). The segment of pSLT absent in pUO-StVR2 is shown within a gray box.