title: Serogroup, virulence, and molecular traits of Vibrio parahaemolyticus isolated from clinical and cockle sources in northeastern Thailand.
abstract: Vibrio parahaemolyticus is responsible for seafood-borne gastroenteritis worldwide. Isolates of V. parahaemolyticus from clinical samples (n=74) and cockles (Anadara granosa) (n=74) in Thailand were analyzed by serotyping, determination of virulence and related marker genes present, response to antimicrobial agents, and genetic relatedness. Serological analysis revealed 31 different serotypes, 10 of which occurred among both clinical and cockle samples. The clinical isolates commonly included the pandemic serogroup O3:K6, while a few of the cockle isolates exhibited likely pandemic serovariants such as O3:KUT and O4:KUT, but not O3:K6. The pandemic (orf8 gene-positive) strains were more frequently found among clinical isolates (78.4%) than cockle isolates (28.4%) (p<0.001). Likewise, the virulence and related marker genes were more commonly detected among clinical than cockle isolates; i.e., tdh gene (93.2% versus 29.7%), vcrD2 (97.3% versus 23.0%), vopB2 (89.2% versus 13.5%), vopT (98.6% versus 36.5%) (all p<0.001) and trh (10.8% versus 1.4%) (p<0.05). Pulsed-field gel electrophoresis of NotI-digested genomic DNA of 41 randomly selected V. parahaemolyticus isolates representing different serotypes produced 33 pulsotypes that formed 5 different clusters (clonal complexes) (A-E) in a dendrogram. Vibrio parahaemolyticus O3:K6 and likely related pandemic serotypes were especially common among the numerous clinical isolates in cluster C, suggesting a close clonal link among many of these isolates. Most clinical and cockle isolates were resistant to ampicillin. This study indicates that O3:K6 and its likely serovariants based on the PFGE clusters, are causative agents. Seafoods such as cockles potentially serve as a source of virulent V. parahaemolyticus, but further work is required to identify possible additional sources.
authors.affiliation: Department of Microbiology, and Diagnostic Center for Emerging Infectious Disease, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Wanida
authors.initials: W
authors.lastname: Mala
authors.affiliation: International Center for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Mohakhali, Dhaka 1212, Bangladesh.
authors.forename: Munirul
authors.initials: M
authors.lastname: Alam
authors.affiliation: Research Group for Preventive Technology in Livestock, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Sunpetch
authors.initials: S
authors.lastname: Angkititrakul
authors.affiliation: Department of Microbiology, and Diagnostic Center for Emerging Infectious Disease, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Suwin
authors.initials: S
authors.lastname: Wongwajana
authors.affiliation: Department of Microbiology, and Diagnostic Center for Emerging Infectious Disease, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Viraphong
authors.initials: V
authors.lastname: Lulitanond
authors.affiliation: National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Thailand.
authors.forename: Sriwanna
authors.initials: S
authors.lastname: Huttayananont
authors.affiliation: Department of Microbiology, and Diagnostic Center for Emerging Infectious Disease, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Wanlop
authors.initials: W
authors.lastname: Kaewkes
authors.affiliation: Department of Microbiology, and Diagnostic Center for Emerging Infectious Disease, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Kiatichai
authors.initials: K
authors.lastname: Faksri
authors.affiliation: Department of Microbiology, and Diagnostic Center for Emerging Infectious Disease, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. Electronic address: chariya@kku.ac.th.
authors.forename: Chariya
authors.initials: C
authors.lastname: Chomvarin
mesh_terms: D000818:Animals; D049873:Cardiidae / Q000382:microbiology*; D005798:Genes, Bacterial; D005843:Geography; D006801:Humans; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D065288:Serogroup; D012703:Serotyping; D013785:Thailand / Q000453:epidemiology; D014735:Vibrio Infections / Q000453:epidemiology* / Q000382:microbiology*; D014736:Vibrio parahaemolyticus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
keywords: Clinical source; Cockle source; Pulsed-field gel electrophoresis; Serogroup; Vibrio parahaemolyticus; Virulence gene