Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/27/2003
Publication Date: 9/14/2003
Citation: CHEN, C., NACE JR, G.W., BRIGGS, C.E., SOLOW, B., FRATAMICO, P.M. CHARACTERIZATION OF TWO PLASMIDS THAT POSSESS ANTIBIOTIC RESISTANCE GENES IN SALMONELLA ENTERICA SEROVAR TYPHIMURIUM U302 STRAIN G8430. MEETING ABSTRACT. 2003. Interpretive Summary:
Technical Abstract: Multidrug-resistant (MR) Salmonella enterica serovar Typhimurium (S. Typhimurium) DT104 and related phage type U302 have been linked to outbreaks of disease in humans and animals worldwide. S. Typhimurium MR U302 strain G8430 (CDC, human isolate) exhibits the ACSSuT resistance phenotype with additional resistance to carbenicillin, erythromycin, kanamycin (Kan), and gentamicin (Gent). Total DNA from G8430 was purified and electroporated into E. coli DH5alpha. Plasmids were purified from the Kan- or Gent-resistant colonies using the Qiagen Large-Construct kit. Various restriction enzymes were used to generate libraries in pUC19. Subclones were sequenced using dye-terminator chemistry on an ABI 3700 sequencer. Sequence assembly and annotation were performed using Sequencher, BLASTP and Artemis. Two antibiotic resistance plasmids, 3.2 kb and 84.5 kb in size, were isolated and sequenced. The 3.2-kb plasmid, pU302S, carries an aph gene and is similar to regions of the E. coli O157:H7 small plasmid pOSAK1 (3.3-kb) and the S. Typhimurium plasmid NTP16 (8-kb). The large MR plasmid, pU302L, carries aac3, aph, sulII tetA/R, strA/B, blaTEM-1, mph, the mer operon, and multiple IS elements. It shares extensive homology with the F and R100 plasmids, and virulence plasmids from S. typhi, Shigella flexneri, and E. coli O157:H7 (pO157). This is the first known report of the complete sequence of a large S. Typhimurium MR plasmid that does not carry spv virulence genes. Regions of homology to plasmids in related bacteria suggest that genetic elements containing resistance genes can be transferred among enteric bacteria including E. coli, Salmonella and Shigella spp. Our results will further the understanding of the evolution of MR strains.