title: Occurrence, seasonality and genetic diversity of Vibrio vulnificus in coastal seaweeds and water along the Kii Channel, Japan.
abstract: Vibrio vulnificus is a ubiquitous toxigenic bacterium found in a coastal environment but little is known about its occurrence and seasonality among seaweeds, which are widely consumed as seafood in Japan. Therefore, we have observed the bacterium's abundance in seawater and seaweed samples from three areas of the Kii Channel, Japan, during June 2003 to May 2004. A total of 192 samples were collected: 24 from each source in summer, autumn, winter and spring. The samples were selectively cultivated following the most probable number (MPN) technique. Vibrio vulnificus population ranged from 0 to 10(3) MPN 100 mL(-1) seawater or 10 g seaweeds; higher counts were observed during summer. The optimum temperature, salinity and pH for the bacterium were 20-24 degrees C, 24-28 p.p.t. and 7.95-8.15, respectively. However, seaweeds always contained higher V. vulnificus than seawater. Among 280 V. vulnificus strains, detected by species-specific colony hybridization and PCR, 78, 74, 11 and 16 were from seaweeds and 46, 42, 2 and 11 were from seawater during summer, autumn, winter and spring, respectively. Ribotyping of 160 selected strains revealed a higher genotypic diversity (18 patterns) among strains from seaweeds than from seawater (10 patterns). Seaweeds can thus act as a potential habitat for V. vulnificus and are more unsafe for consumption during summer.
authors: Environmental Microbiology Laboratory, Laboratory Sciences Division, International Centre for Diarrhoeal Disease Research, Mohakhali, Dhaka, Bangladesh. zhmahmud@icddrb.org
authors: Zahid Hayat
authors: ZH
authors: Mahmud
authors: Sucharit Basu
authors: SB
authors: Neogi
authors: Afework
authors: A
authors: Kassu
authors: Bui Thi
authors: BT
authors: Mai Huong
authors: Iqbal Kabir
authors: IK
authors: Jahid
authors: Mohammad Sirajul
authors: MS
authors: Islam
authors: Fusao
authors: F
authors: Ota
mesh_terms: D016000:Cluster Analysis; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D007564:Japan; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D021521:Ribotyping; D012621:Seasons; D012623:Seawater / Q000382:microbiology*; D012624:Seaweed / Q000382:microbiology*; D012965:Sodium Chloride; D013696:Temperature; D041261:Vibrio vulnificus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D012965:Sodium Chloride