一起由两种罕见血清型副溶血性弧菌引起食物中毒事件分析

目的 分析一起由两种罕见血清型混合感染引起的副溶血性弧菌食物中毒病原学的检测结果,为食物中毒病原学检查途径提供依据。方法 对一起在龙门县人民医院就诊食物中毒事件的9例患者采集其肛拭子样本,参照《食品微生物学检验副溶血性弧菌检验》( GB 4789.7—2013) 等标准进行病原学分析鉴定。结果 本次事件出现临床症状者9例,其中≤20岁2例,20~<40岁1例,40~<60岁4例,≥60岁2例;9份肛拭子样本检出8株副溶血性弧菌,血清分型O2:K28构成比占25.00%(2/8);O8:K21构成比占75.00%(6/8);经PFGE分子分型,2株O2∶K28血清型(VP18171、VP18175)相似度为66.7%;3株O8∶K21血清型(VP18172、VP18173、VP18176)相似度为100.0%,与另外3株O8∶K21血清型(VP18177、VP18174、VP18170)相似度为88.4%~95.2%;药敏试验结果显示,除有1株菌株对氨苄西林、头孢唑林二重耐药、1株菌株对氨苄西林耐药、3株菌株对头孢唑林耐药外,其它菌株对所有测试药物均敏感,无多重耐药现象。结论 此次食物中毒是由O2:K28和O8:K21这两种罕见血清型的副溶血性弧菌混合感染引起的。     

Safety data from the MenB-FHbp clinical development program in healthy individuals aged 10 years and older

BackgroundThe MenB-FHbp vaccine (Trumenba®) is licensed in various countries for the prevention of meningococcal serogroup B disease in individuals ≥ 10 years of age. The clinical development program included 11 completed trials where, in each trial, MenB-FHbp had an acceptable safety profile after a primary vaccination series was administered to individuals 10–65 years of age. However, the detection of potential rare events was limited because of individual clinical trial size. The current safety analysis evaluates pooled reactogenicity and other adverse events (AEs) reported in these trials to identify new safety signals not detectable in individual trials.MethodsEleven trials contributed safety data, of which 10 recorded local and systemic reactogenicity events; 8 of the trials were controlled, and reactogenicity data were pooled for 7 of these 8 trials. Additional AE evaluations included immediate AEs (IAEs), medically attended AEs (MAEs), serious AEs (SAEs), newly diagnosed chronic medical conditions (NDCMCs), and autoimmune or neuroinflammatory conditions.ResultsLocal and systemic reactions were more frequent in the MenB-FHbp group (n = 15,294) compared with controls (n = 5509), although most reactions were transient and mild to moderate in severity. Frequencies of IAEs, SAEs, MAEs, NDCMCs, and autoimmune or neuroinflammatory conditions were similar between the MenB-FHbp and control groups.ConclusionsMenB-FHbp demonstrated a favorable safety and tolerability profile in the clinical development program of > 15,000 vaccine recipients ≥ 10 years of age. No new safety signals were identified in the pooled analysis compared with data from the individual trials. Continued postmarketing safety surveillance is important for the identification of rare events.Clinicaltrials.gov: NCT01299480; NCT000808028; NCT00879814; NCT00780806; NCT01352845; NCT01352793; NCT01461993; NCT01323270; NCT01830855; NCT01461980; NCT01768117.     

A new emerging serotype of Vibrio parahaemolyticus in China is rapidly becoming the main epidemic strain

ObjectivesDuring surveillance, we found a new type of Vibrio parahaemolyticus named ‘O4:KUT-recAin’ and studied the phenotypic, pathogenic and epidemiological characteristics of O4:KUT-recAin.MethodsV. parahaemolyticus were isolated from acute diarrhoeal patients in coastal hospitals of China. Serum agglutination test, specific PCR assay, growth curves under different conditions and rabbit diarrhoeal models were using to characterize O4:KUT-recAin.ResultsThe O4:KUT-recAin strain has a new type of K antigen and a 25 043-bp-large fragment encoding 20 proteins inserted in the housekeeping gene recA. Retrospective analysis found that only one O4:KUT-recAin strain was detected in 563 V. parahaemolyticus strains in 2014; then the proportion increased rapidly and reached 17.8% (105/590) in 2016 and 31.1% (224/721) in 2017, making O4:KUT-recAin the second dominant serotype following O3:K6. O4:KUT-recAin strains (100%, 14/14) exhibited increased acid resistance and could reproduce in medium at pH 4.9, while 92.9% (13/14) of the O3:K6 strains could not grow at this pH value. O4:KUT-recAin could cause diarrhoea and small intestinal tissue lesions in infant rabbits, but its diarrhoeal (93.1%, 27/29) and mortality (78.6%, 22/28) rates were slightly lower than those of O3:K6 (100% 16/16, 100% 16/16). Based on diarrhoea patients, there were no significant differences in the two groups for most clinical symptoms and laboratory results, except media age, haemoglobin and the number of red blood cells in stool samples.ConclusionsO4:KUT-recAin had enhanced acid resistance, was capable of causing infectious diarrhoea in both rabbits and humans, and has become widespread during a short period of time in China.     

基于vvhA基因TaqMan实时荧光定量PCR快速检测创伤弧菌的研究

目的建立基于溶细胞毒素基因vvhA检测创伤弧菌（Vibrio vulnificus）的TaqMan实时荧光定量PCR。方法采用Primer Express软件，设计位于vvhA基因序列保守区的PCR引物和TaqMan探针，建立检测创伤弧菌vvhA基因100bp扩增产物的TaqMan实时荧光定量PCR。采用基因克隆技术，构建作为阳性对照的pMD19-vvhA100重组质粒。以最低扩增循环数（Ct值）、荧光强度增加值（△Rn）为观察指标，对vvhA基因TaqMan实时荧光定量PCR条件进行优化。以不同浓度的创伤弧菌及其它8种细菌DNA和pMD19-vvhA100为模板，对vvhA基因TaqMan实时荧光定量PCR的特异性、敏感性和重复性进行验证。创伤弧菌经腹腔和皮下注射及灌胃感染ICR小鼠，验证vvhA基因TaqMan实时荧光定量PCR对感染小鼠血液、皮下感染组织和肠内容物的检测效果。结果所建立的vvhA基因TaqMan实时荧光定量PCR仅对创伤弧菌DNA或pMD19-vvhA100呈现阳性检测结果，其检测灵敏度可达0．01ng创伤弧菌DNA或10^3个拷贝的pMD19-vvhA100，不同浓度pMD19-vvhA100三次检测结果的SD≤0．79，对腹腔和皮下感染创伤弧菌的小鼠血液、皮下组织标本检测结果均为阳性。结论所建立的创伤弧菌vvhA基因TaqMan实时荧光定量PCR具有快速、稳定、敏感、特异等优点，适合用于临床实验室进行创伤弧菌引起的败血症和创口感染快速诊断。     

抗菌药物联合乌司他丁对酒精性肝病大鼠创伤弧菌脓毒症的作用

目的探讨抗菌药物联合乌司他丁对酒精性肝病大鼠创伤弧菌脓毒症的实验治疗作用。方法采用酒精灌胃联合自由饮酒制作大鼠酒精性肝病模型，右下肢皮下注射创伤弧菌感染肝病大鼠，制作酒精性肝病大鼠创伤弧菌脓毒症模型15只，随机分1～3组，分别于染菌后12h经腹腔注射药物，1次／12h，治疗10d。第1组用等量生理盐水作为对照，第2组应用头孢哌酮和左氧氟沙星，第3组应用头孢哌酮和左氧氟沙星联合乌司他丁。观察大鼠的活动、皮肤黏膜颜色、右下肢感染创口、存活数等。第1组大鼠死亡后，第2组和第3组治疗10d后颈动脉取血液及患肢病变组织进行细菌培养，取大鼠右大腿肌肉、肝脏、肺脏的电镜标本，观察治疗前后细胞超微结构改变。结果各组大鼠12h后，皮温升高，右下肢明显肿胀，皮肤发紫，精神萎靡，活动减少，呼吸急促。第1组大鼠均在24～48h内死亡，血液及患肢病变组织培养出创伤弧菌。2、3组大鼠药物治疗后，精神萎靡状态及呼吸急促等明显改善，3～5d后患侧大腿病变处溃破糜烂，10d后两组大鼠均存活，血液及患肢病变组织培养均为阴性。第3组与第2组比较，前者状态恢复好。抗菌药物治疗前后主要脏器细胞的超微结构改变明显减轻，抗菌药物联合乌司他丁对细胞超微结构改变减轻更为显著。结论应用足量头孢哌酮和左氧氟沙星对酒精性肝病大鼠创伤弧菌脓毒症具有显著的疗效，头孢哌酮和左氧氟沙星联合乌司他丁的疗效更佳，为临床治疗创伤弧菌脓毒症提供了可靠依据。     

一起引起食物中毒的非O1群霍乱弧菌实验室鉴定

目的 查明引发浙江省宁波市某服饰公司食物中毒事件的病原菌.方法 对采集到可疑食品和肛拭等标本参照GB/T4789-2003标准进行细菌的分离、鉴定及血清学分型;参照霍乱防治手册检测菌株的CT毒力基因.结果 6份患者大便标本与14份轻微腹泻患者或腹部不适者大便标本中检出非O1群霍乱弧菌O29血清型9株,其中腹泻患者标本检出6株,轻微腹泻患者中检出3株,检出率为45.0%.未检出志贺菌、副溶血性弧菌、致病性大肠杆菌、O1群和O139霍乱弧菌、金黄色葡萄球菌等致病菌,剩余食物未检出志贺菌、副溶血性弧菌、致病性大肠杆菌、O1群和O139霍乱弧菌、金黄色葡萄球菌等致病菌.结论 此次食物中毒为非O1群霍乱弧菌O29血清型所致.     

霍乱弧菌的分子分型方法

在霍乱流行和暴发调查中,追溯传染源和调查传播途径往往需要对霍乱弧菌进行分型分析.对霍乱弧菌进行血清分型和噬菌体一生物分型,是得到菌株基本信息不可缺少的手段.如果想要揭示菌株在分子水平上的变异和进化规律,则需要进行分子分型分析.本研究对霍乱弧菌的各种分子分型方法进行逐一介绍并加以综合比较.     

抗河流弧菌单克隆抗体的建立及初步鉴定

目的 制备高效、特异的抗河流弧菌单克隆抗体(monoclonal antibody,mAb),为海洋致病细菌的快速免疫诊断提供技术支持.方法 选用雌性BALB/c小鼠(8周龄)制备成为灭活河流弧菌免疫小鼠,利用杂交瘤细胞融合技术,制备出抗河流弧菌杂交瘤细胞株,用Giemsa染色对其进行染色体鉴定,并用酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)方法筛选其与河流弧菌及其他重要海洋细菌的交叉反应特异性.结果 共获得4株抗河流弧菌mAb,均符合杂交瘤细胞染色体特点,具有良好的特异性和免疫反应性,分别命名为01H10,02F12,05F3和03G10.结论 本研究制备、筛选出抗河流弧菌的mAb,有助于建立抗河流弧菌快速免疫检测试剂盒.     

临床分离非O1/O139群霍乱弧菌毒力及耐药特征分析

目的 了解临床分离的非O1/O139群霍乱弧菌毒力及耐药特征。方法 收集2014-2015年北京友谊医院4-10月肠道门诊分离到的非O1/O139群霍乱弧菌,采用微量肉汤稀释法检测霍乱弧菌对15种抗生素的耐药性;PCR检测霍乱弧菌的毒力相关基因。结果 35株非O1/O139群霍乱弧菌对复方新诺明的耐药率(40.0%)最高,其次是氯霉素(28.5%)和磺胺异恶唑(22.6%),对阿莫西林/克拉维酸、头孢曲松、头孢西丁、头孢吡肟及亚胺培南完全敏感。毒力基因检测显示所有菌株均携带hlyA和ompU,hapA(97.1%)、rtxA(91.4%)、Ⅵ型分泌系统T6SS(94.3%~97.1%)、Ⅲ型分泌系统T3SS(80.0%~85.7%)和nanH(62.9%)阳性率较高;主要的毒力基因型为hlyA-rtxA-hapA-ompU-nanH-vasA-vasK-vasH-vcsC-vcsV-vcsN-vspD(40.0%)。结论 临床分离非O1/O139群霍乱弧菌毒力基因多样化,对抗菌药物耐药性较高,需加强腹泻病例中非O1/O139群霍乱弧菌的毒力及耐药监测。