Disrupting theluxSquorum sensing gene does not significantly affectBacillus anthracisvirulence in mice or guinea pigs

Abstract

Many bacterial species use secreted quorum-sensing autoinducer molecules to regulate cell density- and growth phase-dependent gene expression, including virulence factor production, as sufficient environmental autoinducer concentrations are achieved. Bacillus anthracis, the causative agent of anthrax, contains a functional autoinducer (AI-2) system, which appears to regulate virulence gene expression. To determine if the AI-2 system is necessary for disease, we constructed a LuxS AI-2 synthase-deficient mutant in the virulent Ames strain of B. anthracis. We found that growth of the LuxS-deficient mutant was inhibited and sporulation was delayed when compared with the parental strain. However, spores of the Ames luxS mutant remained fully virulent in both mice and guinea pigs.

Targeting agr- and agr-Like Quorum Sensing Systems for Development of Common Therapeutics to Treat Multiple Gram-Positive Bacterial Infections

“…Research into the role of QS in virulence regulation in these pathogens is in its initial stages, but the action of peptide quormones in these species is not as clear-cut as with the agr operons. LuxS , a QS system best characterized in G- bacteria that uses AHLs as signaling molecules, plays a role in bacterial growth, and this system affects the expression of virulence factors in B. anthracis but its loss does not affect virulence [160–162]. In addition to the luxS system, numerous members of the Bacillus genus express members of the RNPP (Rap, NprR, PlcR, and PrgX) family of quorum sensing operons [56,60,163].…”

Characterization of AI-2/LuxS quorum sensing system in biofilm formation, pathogenesis of Streptococcus equi subsp. zooepidemicus

“…In the case of Staphylococcus epidermidis , LuxS deletion paradoxically increases virulence in a rat model ( Xu et al., 2006 ). Furthermore, in certain bacterial species such as Porphyromonas gingivalis , Bacillus anthracis and Shigella flexneri , LuxS does not appear to be essential for virulence ( Day and Maurelli, 2001 ; Burgess et al., 2002 ; Bozue et al., 2012 ). Our mice experiments reveal the Δ luxS mutant did not significantly affect overall mortality in the mice, suggesting that it may not be an essential factor for the pathogenicity of SEZ in terms of survival outcomes.…”