Chowdhury N R, Chakraborty S, Eampokalap B, Chaicumpa W, Chongsa-Nguan M, Moolasart P, Mitra R, Ramamurthy T, Bhattacharya S K, Nishibuchi M, Takeda Y, Nair G B
National Institute of Cholera and Enteric Diseases, Calcutta, India.
Epidemiol Infect. 2000 Aug;125(1):17-25. doi: 10.1017/s0950268899004070.
Active surveillance of Vibrio parahaemolyticus infection among hospitalized patients in Calcutta, India, showed the appearance of the O4:K68 serovar for the first time in March 1998 alongside the continued predominant incidence of the O3:K6 serovar. Strains belonging to both these serovars have been reported to possess pandemic potential. The genomes of O3:K6 and O4:K68 strains and for comparison, non-O3:K6 and non-O4:K68 strains isolated from two different countries, India and Thailand, were examined by different molecular techniques to determine their relatedness. The O3:K6 and O4:K68 strains from Calcutta and Bangkok carried the tdh gene but not the trh gene. Characterization of representative strains of these two serovars by ribotyping and by arbitrarily primed-polymerase chain reaction (AP-PCR) showed that the isolates had identical ribotype and DNA fingerprint. Pulsed-field gel electrophoresis (PFGE) performed with the same set of strains yielded nearly similar restriction fragment length polymorphism (RFLP) patterns for the O3:K6 and O4:K68 isolates from Calcutta and Thailand. Phylogenetic analysis of the NotI RFLP showed that the O3:K6 and O4:K68 strains formed a cluster with 78-91% similarity thus indicating close genetic relationship between the two different serovars isolated during the same time-frame but from widely separated geographical regions. The non-O3:K6 and non-O4:K68, in contrast, showed different ribotype, AP-PCR and PFGE patterns.
对印度加尔各答住院患者中副溶血性弧菌感染的主动监测显示，1998年3月首次出现了O4:K68血清型，与此同时O3:K6血清型的发病率仍居高不下。据报道，这两种血清型的菌株都具有大流行潜力。通过不同的分子技术对从印度和泰国这两个不同国家分离出的O3:K6和O4:K68菌株以及作为对照的非O3:K6和非O4:K68菌株的基因组进行检测，以确定它们之间的亲缘关系。来自加尔各答和曼谷的O3:K6和O4:K68菌株携带tdh基因，但不携带trh基因。通过核糖体分型和任意引物聚合酶链反应（AP-PCR）对这两种血清型的代表性菌株进行鉴定，结果表明这些分离株具有相同的核糖体分型和DNA指纹图谱。对同一组菌株进行脉冲场凝胶电泳（PFGE）分析，结果显示来自加尔各答和泰国的O3:K6和O4:K68分离株产生了几乎相似的限制性片段长度多态性（RFLP）图谱。对NotI RFLP的系统发育分析表明，O3:K6和O4:K68菌株形成了一个相似性为78 - 91%的聚类，这表明在同一时间框架内但来自广泛分离的地理区域分离出的这两种不同血清型之间存在密切的遗传关系。相比之下，非O3:K6和非O4:K68菌株则显示出不同的核糖体分型、AP-PCR和PFGE图谱。
