title: The plasmidome of a Salmonella enterica serovar Derby isolated from pork meat.
abstract: The complete nucleotide sequences of four plasmids hosted by a Salmonella enterica serovar. Derby strain 6MK1 isolated from pork were determined by shotgun Sanger sequencing. A 107,637 base pairs (bp) conjugative plasmid pSD107 containing 150 putative coding sequences (CDS) could be assigned to the narrow host range incompatibility group IncI1. A detailed annotation of all CDS was carried out, revealing the presence of genes needed for plasmid replication, conjugal transfer, plasmid partitioning and stability as well as resistance to antimicrobials. The resistance determinants dhfrA1, aadA1, qacEΔ1, sul1 (supplied by a class 1 integron), blaTEM-1b (carried by a truncated Tn2 flanked by IS26), sul2 and strAB confer multidrug resistance to the host bacterium. In addition to pSD107, three small cryptic plasmids pSD4.0, pSD4.6 and pSD5.6 were identified, showing significant sequence similarities to already known replicons of Escherichia coli and S. enterica. In conjugation experiments performed on solid medium, pSD107 was successfully transferred to a nalidixic acid resistant E. coli DH5α, mobilizing pSD4.0 and, more infrequently, also pSD4.6. All transferred plasmids were stably propagated in the recipient strain without selective pressure for approximately 66 generations. The absolute plasmid copy numbers were determined in real time PCR experiments, revealing an approximate 1:1:1:1 ratio of the four replicons compared to the chromosome. The evolutionary position of pSD107 within the IncI1 family of plasmids was inferred from a maximum likelihood phylogenetic tree and by comparison of genetic key elements in a set of 17 IncI1 reference plasmids.
authors: Leibniz-Institute for Natural Product Research and Infection Biology, Beutenbergstrasse 11a, Cell and Molecular Biology, D-07745 Jena, Germany. anne.bleicher@hki-jena.de
authors: Anne
authors: A
authors: Bleicher
authors: Gerhard
authors: G
authors: Schöfl
authors: Maria Del Rosario
authors: Mdel R
authors: Rodicio
authors: Hans Peter
authors: HP
authors: Saluz
mesh_terms: D000818:Animals; D001483:Base Sequence; D002876:Chromosomes, Bacterial / Q000235:genetics; D003227:Conjugation, Genetic; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005516:Food Microbiology; D005798:Genes, Bacterial; D008460:Meat / Q000382:microbiology*; D058977:Molecular Sequence Annotation; D009268:Nalidixic Acid / Q000494:pharmacology; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics*; D019779:Salmonella enterica / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D013552:Swine; D026801:Synteny
chemical_list: D004269:DNA, Bacterial; D009268:Nalidixic Acid