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Listeria monocytogenes relA and hpt Mutants Are Impaired in Surface-Attached Growth and Virulence

Taylor, Clare M.; Beresford, Mark; Epton, Harry A. S.; Sigee, David C.; Shama, Gilbert; Andrew, Peter W.; Roberts, Ian S.


Mark Beresford

Harry A. S. Epton

David C. Sigee

Gilbert Shama

Peter W. Andrew

Ian S. Roberts


We describe here the identification and characterization of two Listeria monocytogenes (Tn917-LTV3) relA and hpt transposon insertion mutants that were impaired in growth after attachment to a model surface. Both mutants were unable to accumulate (p)ppGpp in response to amino acid starvation, whereas the wild-type strain accumulated (p)ppGpp within 30 min of stress induction. The induction of transcription of the relA gene after adhesion was demonstrated, suggesting that the ability to mount a stringent response and undergo physiological adaptation to nutrient deprivation is essential for the subsequent growth of the adhered bacteria. The absence of (p)ppGpp in the hpt mutant, which is blocked in the purine salvage pathway, is curious and suggests that a functional purine salvage pathway is required for the biosynthesis of (p)ppGpp. Both mutants were avirulent in a murine model of listeriosis, indicating an essential role for the stringent response in the survival and growth of L. monocytogenes in the host. Taken as a whole, this study provides new information on the role of the stringent response and the physiological adaptation of L. monocytogenes for biofilm growth and pathogenesis.


Taylor, C. M., Beresford, M., Epton, H. A. S., Sigee, D. C., Shama, G., Andrew, P. W., & Roberts, I. S. (2002). Listeria monocytogenes relA and hpt Mutants Are Impaired in Surface-Attached Growth and Virulence. Journal of Bacteriology, 184(3), 621-628.

Journal Article Type Article
Acceptance Date Nov 1, 2001
Publication Date 2002-02
Deposit Date Jul 27, 2016
Journal Journal of Bacteriology
Print ISSN 0021-9193
Publisher American Society for Microbiology
Peer Reviewed Peer Reviewed
Volume 184
Issue 3
Pages 621-628
Keywords Listeria monocytogenes, Tn917-LTV3, pathogenesis,
Public URL