title: Leptospira interrogans catalase is required for resistance to H2O2 and for virulence.
abstract: Pathogenic Leptospira spp. are likely to encounter higher concentrations of reactive oxygen species induced by the host innate immune response. In this study, we characterized Leptospira interrogans catalase (KatE), the only annotated catalase found within pathogenic Leptospira species, by assessing its role in resistance to H(2)O(2)-induced oxidative stress and during infection in hamsters. Pathogenic L. interrogans bacteria had a 50-fold-higher survival rate under H(2)O(2)-induced oxidative stress than did saprophytic L. biflexa bacteria, and this was predominantly catalase dependent. We also characterized KatE, the only annotated catalase found within pathogenic Leptospira species. Catalase assays performed with recombinant KatE confirmed specific catalase activity, while protein fractionation experiments localized KatE to the bacterial periplasmic space. The insertional inactivation of katE in pathogenic Leptospira bacteria drastically diminished leptospiral viability in the presence of extracellular H(2)O(2) and reduced virulence in an acute-infection model. Combined, these results suggest that L. interrogans KatE confers in vivo resistance to reactive oxygen species induced by the host innate immune response.
authors.affiliation: Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.
authors.forename: Azad
authors.initials: A
authors.lastname: Eshghi
authors.forename: Kristel
authors.initials: K
authors.lastname: Lourdault
authors.forename: Gerald L
authors.initials: GL
authors.lastname: Murray
authors.forename: Thanatchaporn
authors.initials: T
authors.lastname: Bartpho
authors.forename: Rasana W
authors.initials: RW
authors.lastname: Sermswan
authors.forename: Mathieu
authors.initials: M
authors.lastname: Picardeau
authors.forename: Ben
authors.initials: B
authors.lastname: Adler
authors.forename: Brendan
authors.initials: B
authors.lastname: Snarr
authors.forename: Richard L
authors.initials: RL
authors.lastname: Zuerner
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Cameron
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism*; D006224:Cricetinae; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D015151:Immunoblotting; D007921:Leptospira interrogans / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D007922:Leptospirosis / Q000276:immunology / Q000382:microbiology*; D008297:Male; D008969:Molecular Sequence Data; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D014774:Virulence / Q000502:physiology*
chemical_list: D006861:Hydrogen Peroxide; D002374:Catalase