title: Virulence of Burkholderia mallei quorum-sensing mutants.
abstract: Many Proteobacteria use acyl-homoserine lactone-mediated quorum-sensing (QS) to activate specific sets of genes as a function of cell density. QS often controls the virulence of pathogenic species, and in fact a previous study indicated that QS was important for Burkholderia mallei mouse lung infections. To gain in-depth information on the role of QS in B. mallei virulence, we constructed and characterized a mutant of B. mallei strain GB8 that was unable to make acyl-homoserine lactones. The QS mutant showed virulence equal to that of its wild-type parent in an aerosol mouse infection model, and growth in macrophages was indistinguishable from that of the parent strain. Furthermore, we assessed the role of QS in B. mallei ATCC 23344 by constructing and characterizing a mutant strain producing AiiA, a lactonase enzyme that degrades acyl-homoserine lactones. Although acyl-homoserine lactone levels in cultures of this strain are very low, it showed full virulence. Contrary to the previous report, we conclude that QS is not required for acute B. mallei infections of mice. QS may be involved in some stage of chronic infections in the natural host of horses, or the QS genes may be remnants of the QS network in B. pseudomallei from which this host-adapted pathogen evolved.
authors: Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA.
authors: Charlotte
authors: C
authors: Majerczyk
authors: Loren
authors: L
authors: Kinman
authors: Tony
authors: T
authors: Han
authors: Richard
authors: R
authors: Bunt
authors: E Peter
authors: EP
authors: Greenberg
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D019121:Burkholderia Infections / Q000235:genetics / Q000382:microbiology*; D042726:Burkholderia mallei / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D053038:Quorum Sensing / Q000502:physiology*; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins