Virulence of Pasteurella multocida recA mutants

Maribel Cárdenas, Antonio R. Fernández De Henestrosa, Susana Campoy, Ana M. Perez De Rozas, Jordi Barbé, Ignacio Badiola, Montserrat Llagostera

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23 Citations (Scopus)


In order to determine the role of the recA protein in the virulence of Pasteurella multocida, a recA mutant was constructed and used in studies of virulence and competition in relation to wild-type strain. To achieve this, firstly, the recA gene was isolated and sequenced, showing an Escherichia coli-like SOS box and encoding a protein of 354 amino acids which has the closest identity with the Haemophilus influenzae recA protein. Further, the recA mutant was constructed, by inactivating this gene by single recombination of a suicide plasmid containing an internal region of the P. multocida recA gene, and shown to be more sensitive to UV radiation than the parental strain. The P. multocida mutant was slightly attenuated in virulence, as indicated by the LD50, the time of death of infected animals, and a failure to compete with the wild-type strain in mixed infections. Compared to the parent strain, the mutant had a similar growth rate but a longer lag phase. These data suggest that the diminished virulence of the recA mutant as well as its failure in competition were more a consequence of the long lag phase rather than a direct effect of the inactivation of the recA gene on genes involved in virulence. © 2001 Elsevier Science B.V.
Original languageEnglish
Pages (from-to)53-61
JournalVeterinary Microbiology
Issue number1
Publication statusPublished - 3 May 2001


  • DNA repair
  • Pasteurella multocida
  • recA gene
  • Virulence genes


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