title: Distribution of Aeromonas species in environmental water used in daily life in Okinawa Prefecture, Japan.
abstract: OBJECTIVE
  The genus Aeromonas is known to causes diseases such as food poisoning, sepsis, and wound infection. However, the mode of Aeromonas transmission from environment to humans is not clearly understood. To evaluate the health risks of Aeromonas spp. in environmental freshwater, the number, proportion and putative virulence factors of Aeromonas species were investigated in Okinawa Prefecture, Japan.
  
  
  METHODS
  Environmental freshwater samples were collected from three dams, two springs and three private wells. Aeromonas strains were identified by the biochemical method and the viable count was calculated. The production of extracellular enzymes and the virulence genes were investigated for possessing putative virulence factors using representative isolates.
  
  
  RESULTS
  At least seven species of already-known Aeromonas isolates as well as unidentified Aeromonas spp. with/without arginin dehydrolase (ADH) exist in water at these sites. Aeromonas spp. was found to exist at over 1000 CFU/100 ml in one spring and two wells. A. veronii biovar sobria and A. jandaei were the predominant species in dams, and A. hydrophila and/or A. eucrenophila were predominant in wells. Almost all the sampled Aeromonas species produced protease, gelatinase, lipase, esterase and DNase, but A. caviae, A. caviae-like bacteria, and A. eucrenophila had low hemolytic activity. Most sampled A. hydrophila strains possessed both aerolysin gene (aer) and hemolysin gene (hlyA), but A. caviae and A. eucrenophila strains did not possess either gene.
  
  
  CONCLUSIONS
  Since these results indicated that several Aeromonas species having potential pathogenicity exist in environmental water in Okinawa, surveys are recommended as a public health measure.
authors.affiliation: Laboratory of Microbiology, School of Health Sciences, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, 903-0215, Okinawa, Japan. k-miyagi@med.u-ryukyu.ac.jp.
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Miyagi
authors.affiliation: Laboratory of Microbiology, School of Health Sciences, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, 903-0215, Okinawa, Japan.
authors.forename: Itaru
authors.initials: I
authors.lastname: Hirai
authors.affiliation: Department of Microbiology, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki-shi, 569-8686, Osaka, Japan.
authors.forename: Kouichi
authors.initials: K
authors.lastname: Sano
mesh_terms: D000333:Aeromonas / Q000145:classification / Q000302:isolation & purification*; D060766:Drinking Water / Q000382:microbiology*; D005618:Fresh Water / Q000382:microbiology*; D007564:Japan; D060985:Natural Springs / Q000382:microbiology; D037521:Virulence Factors; D014881:Water Supply; D060986:Water Wells
chemical_list: D060766:Drinking Water; D037521:Virulence Factors
keywords: Aeromonas species; Distribution; Environmental water; Proportion; Putative virulence factors