title: Isolation of Pseudomonas aeruginosa from open ocean and comparison with freshwater, clinical, and animal isolates.
abstract: Pseudomonas aeruginosa is an opportunistic pathogen responsible for morbidity and mortality in humans, animals, and plants. This bacterium has been regarded to be widely present in terrestrial and freshwater environments, but not in open ocean environments. Our purpose was to clarify its presence in open ocean, and their genotypic and physiological characteristics were compared with those of isolates from clinical, animal, and freshwater sources. Water samples were collected from freshwater, bays, and offshore environments in Japan. Sixty-two isolates, including 26 from the open ocean, were identified as P. aeruginosa by phenotypic characteristics and the BD Phoenix System. Pulsed-field gel electrophoresis (PFGE) was performed on all strains, together with 21 clinical and 8 animal strains. The results showed that open ocean strains are composed of a few genotypes, which are separated from other strains. Although some clinical isolates made a cluster, other strains tended to mix together. Different antibiotypes were observed among marine isolates that had similar PFGE and serotyping patterns. Some were multidrug-resistant. Laboratory-based microcosm study were carried out to see the responses of P. aeruginosa toward increased NaCl concentrations in deionized water (DW). Marine strains showed better survival with the increase, whereas river and clinical strains were suppressed by the increase. These findings illustrate the potential significance of open ocean as a possible reservoir of P. aeruginosa, and there may be clones unique to this environment. To our knowledge, this is the first report on the presence and characterization of P. aeruginosa in the open ocean.
authors.affiliation: Marine Microbiology Division, Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-Ku, Tokyo 164-8639, Japan. huda@nenv.k.u-tokyo.ac.jp
authors.forename: Nurul Huda
authors.initials: NH
authors.lastname: Khan
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ishii
authors.forename: Noriko
authors.initials: N
authors.lastname: Kimata-Kino
authors.forename: Hidetake
authors.initials: H
authors.lastname: Esaki
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Nishino
authors.forename: Masahiko
authors.initials: M
authors.lastname: Nishimura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kogure
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003470:Culture Media; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D007564:Japan; D010140:Pacific Ocean; D011552:Pseudomonas Infections / Q000382:microbiology / Q000662:veterinary*; D011550:Pseudomonas aeruginosa / Q000145:classification* / Q000187:drug effects / Q000302:isolation & purification* / Q000502:physiology*; D012965:Sodium Chloride / Q000494:pharmacology; D013045:Species Specificity; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D012965:Sodium Chloride