The virulence plasmid of Salmonella typhimurium is self-transmissible

Brian M.M. Ahmer, Mimi Tran, Fred Heffron

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86 Scopus citations


Most isolates of Salmonella enterica serovar Typhimurium contain a 90- kb virulence plasmid. This plasmid is reported to be mobilizable but nonconjugative. However, we have determined that the virulence plasmid of strains LT2, 14028, and SR-11 is indeed self-transmissible. The plasmid of strain SL1344 is not. Optimal conjugation frequency requires filter matings on M9 minimal glucose plates with a recipient strain lacking the virulence plasmid. These conditions result in a frequency of 2.9 x 10-4 transconjugants/donor. Matings on Luria-Bertani plates, liquid matings, or matings with a recipient strain carrying the virulence plasmid reduce the efficiency by up to 400-fold. Homologs of the F plasmid conjugation genes are physically located on the virulence plasmid and are required for the conjugative phenotype.

Original languageEnglish (US)
Pages (from-to)1364-1368
Number of pages5
JournalJournal of bacteriology
Issue number4
StatePublished - Feb 1999
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


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