A significant role for Sigma B in the detergent stress response of Listeria monocytogenes.
OBJECTIVE
To investigate the contribution of the alternative sigma factor Sigma B to detergent stress in Listeria monocytogenes upon exposure to the surface-active agents, benzalkoniumchloride (BC), cetylpyridinium chloride (CPC) and sodium docecyl sulfate (SDS).


RESULTS
Surfactant/detergent stress in L. monocytogenes 10403S and a DeltasigB mutant of 10403S was investigated by lethality, impact on growth and by transcriptional analysis. We observed a significant 1-2 log decrease in the viability of the DeltasigB mutant in response to lethal levels of surfactants. Transcriptional (reverse transcriptase-PCR) analysis revealed the induction of sigmaB by sublethal levels of surface-active agents. However, Sigma B does not play a significant role in the growth of L. monocytogenes upon exposure to sublethal levels as investigated by growth analysis.


CONCLUSIONS
Sigma B is essential for the resistance of L. monocytogenes at lethal levels of BC, CPC and SDS.


CONCLUSIONS
We demonstrate that Sigma B is essential for the resistance of the pathogen to surfactant stress. The findings raise the possibility that induction of Sigma B by sublethal levels of industrial cleaning agents may promote enhanced resistance of further food-processing associated stresses or conditions encountered during infection. Sigma B-regulated mechanisms of detergent resistance may provide targets for the future design of novel cleaning agents.
Ryan
E M
EM
Department of Microbiology, University College Cork, Cork, Ireland.
Gahan
C G M
CG
Hill
C
C
D001548:Benzalkonium Compounds / Q000494:pharmacology; D002594:Cetylpyridinium / Q000494:pharmacology; D003902:Detergents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology
D001548:Benzalkonium Compounds; D003902:Detergents; D012808:Sigma Factor; D012967:Sodium Dodecyl Sulfate; D002594:Cetylpyridinium