title: Impact of Acinetobacter baumannii superoxide dismutase on motility, virulence, oxidative stress resistance and susceptibility to antibiotics.
abstract: Acinetobacter baumannii is a Gram-negative bacterium appearing as an opportunistic pathogen in hospital settings. Superoxide dismutase (SOD) contributes to virulence in several pathogenic bacteria by detoxifying reactive oxygen species released in the course of host defense reactions. However, the biological role of SODs in A. baumannii has not yet been elucidated. Here, we inactivated in A. baumannii ATCC 17978 gene A1S_2343, encoding a putative SOD of the Fe-Mn type by transposon insertion, resulting in mutant ATCC 17978 sod2343::Km. The mutation was also introduced in two naturally competent A. baumannii isolates by transformation with chromosomal DNA derived from mutant ATCC 17978 sod2343::Km. We demonstrate that inactivation of sod2343 leads to significant motility defects in all three A. baumannii strains. The mutant strains were more susceptible to oxidative stress compared to their parental strains. Susceptibility to colistin and tetracycline was increased in all mutant strains while susceptibility of the mutants to gentamicin, levofloxacin and imipenem was strain-dependent. In the Galleria mellonella infection model the mutant strains were significantly attenuated. In conclusion, sod2343 plays an important role in motility, resistance to oxidative stress, susceptibility to antibiotics and virulence in A. baumannii.
authors.affiliation: Robert Koch-Institute, Wernigerode Branch, Wernigerode, Germany.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Heindorf
authors.affiliation: Robert Koch-Institute, Wernigerode Branch, Wernigerode, Germany.
authors.forename: Mahendar
authors.initials: M
authors.lastname: Kadari
authors.affiliation: Robert Koch-Institute, Wernigerode Branch, Wernigerode, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Heider
authors.affiliation: Robert Koch-Institute, Wernigerode Branch, Wernigerode, Germany.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Skiebe
authors.affiliation: Robert Koch-Institute, Wernigerode Branch, Wernigerode, Germany.
authors.forename: Gottfried
authors.initials: G
authors.lastname: Wilharm
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000201:enzymology* / Q000378:metabolism / Q000472:pathogenicity; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004789:Enzyme Activation / Q000187:drug effects; D007915:Lepidoptera / Q000382:microbiology; D009068:Movement / Q000187:drug effects; D009154:Mutation; D018384:Oxidative Stress / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase