Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Laboratorio Nazionale di Riferimento Contaminazioni Batteriologiche molluschi bivalvi, Ancona, Italy.
Environ Microbiol. 2013 May;15(5):1377-86. doi: 10.1111/j.1462-2920.2012.02839.x. Epub 2012 Aug 14.
The relationship between Vibrio parahaemolyticus strains isolated from the aquatic environment and those isolated from cases of infection in humans is poorly understood due to the low prevalence of tdh- and/or trh-positive strains in the environment. To address this concern, it would be useful to analyse the genetic relationships among environmental and food strains and with reference to clinical isolates, also applying molecular typing methods. The aim of this study was to evaluate the prevalence of toxigenic V.parahaemolyticus in Italian coastal waters and seafood, to examine intra-species variability and to identify, using serotyping and pulsed-field gel electrophoresis (PFGE), relationships among strains from different sources, geographical origin and period of isolation. Of the 192 V.parahaemolyticus strains isolated in different Italian areas and examined in this study, 25 (13.0%) proved to carry the trh gene while none of the strains proved positive to the search by PCR for tdh and Group-Specific-toxRS genes. The prevalence of toxigenic strains in the Tyrrhenian Sea was significantly lower than that calculated for the Ligurian coasts. Regarding the sources of isolation, the higher prevalence of trh-positive V.parahaemolyticus was revealed in fish, followed by clams, plankton, oysters, mussels and lastly seawater. Within the toxigenic strains, 16 serotypes and 20 distinct PFGE patterns were identified. Two clusters, which included a total of 8 V.parahaemolyticus strains, were specifically associated with the North Adriatic Sea area and were stable over time. Our results demonstrate that trh-positive V.parahaemolyticus strains circulated in Italy in the period 2002-2009 with a prevalence higher than that reported from other European and extra-European countries, confirming that toxigenic V.parahaemolyticus is an emerging public health concern in Italy, regardless of its pandemic potential.
由于环境中 tdh- 和/或 trh- 阳性菌株的流行率较低，因此，水生环境中分离出的霍乱弧菌菌株与人类感染病例中分离出的菌株之间的关系尚不清楚。为了解决这一问题，分析环境和食品菌株与临床分离株之间的遗传关系，并应用分子分型方法将是很有用的。本研究旨在评估意大利沿海水域和海鲜中产毒霍乱弧菌的流行情况，检查种内变异性，并通过血清分型和脉冲场凝胶电泳（PFGE）鉴定不同来源、地理来源和分离时间的菌株之间的关系。在本研究中，从意大利不同地区分离的 192 株霍乱弧菌中，有 25 株（13.0%）携带 trh 基因，而没有一株菌株经 PCR 检测到 tdh 和 Group-Specific-toxRS 基因呈阳性。与利古里亚海岸相比，在第勒尼安海发现产毒菌株的流行率明显较低。关于分离源，在鱼类中发现 trh 阳性霍乱弧菌的流行率最高，其次是蛤、浮游生物、牡蛎、贻贝和最后是海水。在产毒菌株中，鉴定出 16 种血清型和 20 种不同的 PFGE 模式。两个集群，共包含 8 株霍乱弧菌，与亚得里亚海北部地区有特定关联，且在时间上保持稳定。我们的研究结果表明，trh 阳性霍乱弧菌菌株于 2002-2009 年在意大利流行，流行率高于其他欧洲和欧洲以外国家的报道，证实产毒霍乱弧菌是意大利一个新出现的公共卫生关注点，无论其是否具有大流行的潜力。
