First clinical report of pandemic Vibrio parahaemolyticus O3:K6 infection in Italy
First clinical report of pandemic Vibrio parahaemolyticus O3:K6 infection in Italy
复制标题
DOI：
10.1128/jcm.00683-08
复制
发表时间：
2008-06-01
影响因子：
9.4
通讯作者：
Carraturo, Antonio
中科院分区：
文献类型：
--
作者：
Ottaviani, Donatella;Leoni, Francesca;Carraturo, Antonio
副溶血性弧菌是一种革兰氏阴性嗜盐菌，广泛分布于世界各地的沿海沃茨，与食用生的或不适当烹饪的海鲜引起的胃肠炎有关。耐热直接溶血素（TDH）和TDH相关溶血素是主要的毒力因子。在过去的几十年中，包括O3：K6在内的多种血清型与人类胃肠道疾病有关。然而，自1996年以来，出现了一种具有大流行潜力的血清型O3：K6的新克隆，这是亚洲、非洲和美洲病例发病率增加的原因（5）。先前的研究已经证明，属于旧的和新的O3：K6克隆的副溶血性弧菌临床分离株具有不同的分子模式，但在生物学特征上没有差异，例如TDH产生和对抗生素和环境胁迫的敏感性（4，10）。在欧洲，已在法国（8）、俄罗斯（5）和西班牙（9）的临床样本中检测到大流行性副溶血性弧菌O3：K6菌株。在此，我们报告了2007年夏天从意大利中部住院的腹泻患者粪便样本中分离的大流行性副溶血性弧菌O3：K6菌株的特征。报告的流行病学信息表明，患者在住院前24小时食用了从当地卖家购买的新鲜贝类。医院的微生物实验室在没有其他肠道病原体的情况下分离出一种革兰氏阴性、氧化酶阳性的弯曲细菌。该分离株被推定鉴定为属于弧菌属，并被送往意大利贝类细菌污染参考实验室（CEREM）进行最终鉴定。在硫代硫酸盐柠檬酸盐胆盐琼脂（Oxoid Ltd.，贝辛斯托克，英格兰）在含1% NaCl的胰蛋白胨大豆琼脂（Oxoid）上传代培养，并在属和种水平进行生化鉴定（6）。此外，通过PCR检测所有蔗糖阴性菌落是否存在副溶血性弧菌种特异性基因（toxR和tlh）以及tdh和trh基因（3，7）。基于toxRS基因序列变异的组特异性PCR（GS-PCR）方法也用于检测大流行性克隆（4）。通过使用特异性商业抗血清（Denka; Seiken Corp.，东京，日本）。根据临床和实验室标准化研究所（CLSI）的指导原则（2），在Mueller-Hinton琼脂平板上通过纸片扩散法测定分离株对11种抗菌剂的亲和性。检测的抗生素为阿莫西林-克拉维酸、氨苄西林、头孢哌酮、头孢氨苄、头孢噻吩、粘菌素、庆大霉素、卡那霉素、恶喹酸、四环素和甲氧苄啶磺胺甲恶唑。确定对供试抗菌剂敏感性的解释标准由CLSI（2）发布或遵循抗菌剂供应商的建议。
Vibrio parahaemolyticus is a gram-negative, halophilic bacterium widely distributed in coastal waters worldwide that is associated with gastroenteritis due to the consumption of raw or improperly cooked seafood. The thermostable direct hemolysin (TDH) and TDH-related hemolysin are the major virulence factors. In the past decades, diverse serotypes, including O3: K6, have been related to human gastrointestinal diseases. However, since 1996 the emergence of a new clone of serotype O3: K6 with pandemic potential, which has accounted for an increased incidence of cases in Asia, Africa, and America, has been reported (5). Previous studies have demonstrated that V. parahaemolyticus clinical isolates belonging to both the old and new O3: K6 clones have distinct molecular patterns but do not differ in biological characteristics such as TDH production and susceptibilities to antibiotics and environmental stresses (4, 10). In Europe, pandemic V. parahaemolyticus O3: K6 strains have been detected in clinical samples in France (8), Russia (5), and Spain (9).Here, we report the characterization of a pandemic V. parahaemolyticus O3: K6 strain isolated from a stool sample of a diarrheal patient hospitalized in central Italy in the summer of 2007. The reported epidemiological information indicated that the patient had eaten fresh shellfish, bought from a local seller, 24 h before hospitalization. The microbiology laboratory of the hospital isolated a gram-negative, oxidase-positive curved bacterium in the absence of other enteric pathogens. The isolate, presumptively identified as belonging to the Vibrio genus, was sent to the Italian Reference Laboratory for Bacteriological Contamination of Shellfish (CEREM) for definitive identification. Suspect colonies grown on thiosulfate citrate bile salt agar (Oxoid Ltd., Basingstoke, England) were subcultured on Trypticase soy agar (Oxoid) with 1% NaCl and biochemically identified at the genus and species levels (6). Moreover, all sucrosenegative colonies were tested by PCR for the presence of V. parahaemolyticus species-specific genes (toxR and tlh) and the tdh and trh genes (3, 7). A group-specific PCR (GS-PCR) method, based on the sequence variation in the toxRS gene, was also performed to detect the pandemic clone (4). O (lipopolysaccharide) and K (capsular) serotypes were determined by using specific commercial antisera (Denka; Seiken Corp., Tokyo, Japan). The susceptibilities of the isolate to 11 antimicrobial agents were determined by the disk diffusion method on Mueller-Hinton agar plates according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI)(2). The antibiotics tested were amoxicillin-clavulanic acid, ampicillin, cefoperazone, cephalexin, cephalothin, colistin, gentamicin, kanamycin, oxolinic acid, tetracycline, and trimethoprimsulfamethoxazole. The interpretative criteria to determine the susceptibilities to the tested antimicrobials were as published by the CLSI (2) or followed the recommendations of the antimicrobial agent suppliers.