title: The virB operon is essential for lethality of Brucella microti in the Balb/c murine model of infection.
abstract: In murine infections, Brucella microti exhibits an atypical and highly pathogenic behavior resulting in a mortality of 82%. In this study, the possible involvement of the virB type IV secretion system, a key virulence factor of Brucella sp., in this lethal phenotype was investigated. As previously described for B. suis, expression of the virB operon of B. microti was induced in acid minimal medium, partially mimicking intracellular environment. Early neutralization of cellular compartments abolished intracellular replication of B. microti, showing that acidity of the Brucella-containing vacuole is an essential trigger. A ΔvirB mutant of B. microti exhibited strong attenuation in murine and human macrophages in vitro. Interestingly, infection with this mutant was not lethal in Balb/c mice and lacked the typical intrasplenic peak at 3 days post-infection, hence demonstrating that lethality of B. microti in murine infection absolutely requires a functional virB operon.
authors: Université Montpellier I, Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé (CPBS), F-34095, Montpellier, France.
authors: Nabil
authors: N
authors: Hanna
authors: Maria Pilar
authors: MP
authors: Jiménez de Bagüés
authors: Safia
authors: S
authors: Ouahrani-Bettache
authors: Zoubida
authors: Z
authors: El Yakhlifi
authors: Stephan
authors: S
authors: Köhler
authors: Alessandra
authors: A
authors: Occhialini
mesh_terms: D000643:Ammonium Chloride; D000818:Animals; D002002:Brucella / Q000235:genetics* / Q000472:pathogenicity*; D002006:Brucellosis / Q000382:microbiology* / Q000401:mortality*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008264:Macrophages; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000166:cytology; D014617:Vacuoles / Q000737:chemistry
chemical_list: D000643:Ammonium Chloride