title: Commercial Lysogeny Broth culture media and oxidative stress: a cautious tale.
abstract: Lysogeny Broth (LB), most often misnamed Luria-Bertani medium, ranks among the most commonly used growth media in microbiology. Surprisingly, we observed that oxidative levels vary with the commercial origin of the LB ready to use powder. Indeed, growth on solid media of Escherichia coli and Salmonella derivatives lacking antioxidative stress defenses, such as oxyR mutant devoid of the H2O2-sensing transcriptional activator or Hpx(-) strains lacking catalases and peroxidases, exhibit different phenotypes on LB-Sigma or LB-Difco. Using gene fusion and exogenously added catalase, we found that LB-Sigma contains higher levels of H2O2 than LB-Difco. Also we observed differences in population counts of 82 clinical and environmental isolates of E. coli, depending on the LB used. Further investigations revealed a significant influence of the commercial origin of agar as well. Besides being a warning to the wide population of LB users, our observations provide researchers in the oxidative stress field with a tool to appreciate the severity of mutations in antioxidative stress defenses.
authors.affiliation: Laboratoire de Chimie Bactérienne, Aix Marseille Université-CNRS, UMR 7283, Institut de Microbiologie de la Méditerranée, CNRS, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ezraty
authors.affiliation: Laboratoire de Chimie Bactérienne, Aix Marseille Université-CNRS, UMR 7283, Institut de Microbiologie de la Méditerranée, CNRS, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Henry
authors.affiliation: Laboratoire de Chimie Bactérienne, Aix Marseille Université-CNRS, UMR 7283, Institut de Microbiologie de la Méditerranée, CNRS, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Hérisse
authors.affiliation: INSERM, IAME, UMR 1137, F-75018 Paris, France;; Université Paris Diderot, Sorbonne Paris Cité, F-75018 Paris, France.
authors.forename: Erick
authors.initials: E
authors.lastname: Denamur
authors.affiliation: Laboratoire de Chimie Bactérienne, Aix Marseille Université-CNRS, UMR 7283, Institut de Microbiologie de la Méditerranée, CNRS, 31 Chemin Joseph Aiguier, 13009 Marseille, France. Electronic address: barras@imm.cnrs.fr.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Barras
mesh_terms: D000362:Agar / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics; D002374:Catalase / Q000235:genetics; D003470:Culture Media / Q000737:chemistry*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development*; D029968:Escherichia coli Proteins / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008242:Lysogeny; D009154:Mutation / Q000235:genetics; D015588:Observer Variation; D018384:Oxidative Stress; D009195:Peroxidase / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D012475:Salmonella / Q000235:genetics / Q000254:growth & development*
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C499299:oxyR protein, E coli; D000362:Agar; D006861:Hydrogen Peroxide; D002374:Catalase; D009195:Peroxidase
keywords: Enterobacteriaceae; Media brand; Microbiology; Oxidative stress