鳗鲡创伤弧菌的分子鉴定

目的对分离自发病欧洲鳗鲡的创伤弧菌疑似菌株进行准确的鉴定。方法首先尝试利用一对16SrRNA基因特异性通用引物PCR扩增一株鳗源创伤弧菌疑似株的基因组DNA，得到一个约500bp的DNA片段，将该DNA片段亚克隆至pMDl8-T载体，鉴定克隆化成功之后，送专业公司进行测序，得到一个502bp的DNA产物，NCBI上同源性比较表明，该片段与GeneBank上注册的创伤弧菌的16SrDNA序列同源性最高（100％），同时排除了哈维氏弧菌的可能。设计一对创伤弧菌溶血素特异性引物，实现了对鳗鲡创伤弧菌的分子鉴定。结果建立一种简洁的鳗鲡创伤弧菌的分子鉴定方法。结论国内首次自发病欧鳗分离到创伤弧菌，并给出分子鉴定证据。     

创伤弧菌溶细胞毒素单克隆抗体制备及其鉴定

目的制备创伤弧菌(Vibrio vulnificus)溶细胞素vvhA基因产物鼠源性单克隆抗体并鉴定其特异性和免疫性,为进一步研制创伤弧菌检测试剂盒奠定基础。方法采用IPTG诱导目的重组蛋白rvvhA表达,Ni-NTA亲和层析法提纯rvvhA,SDS-PAGE检测表达和提纯效果。采用杂交瘤技术和rvvhA-ELISA制备并筛选分泌rvvhA单克隆抗体的细胞株,有限稀释法进行细胞克隆。采用免疫双扩散法鉴定单克隆抗体类型。采用ELISA、免疫双扩散法和Western Blot鉴定单克隆抗体的效价和特异性。结果在0.5mmol/L IPTG诱导下,rvvhA产量可占细菌总蛋白的18%。提纯的rvvhA经SDS-PAGE后仅显示单一的蛋白条带。共获得9株rvvhA抗体阳性的杂交瘤细胞株,其中A5E8和C3B6株可持续分泌高效价特异性单克隆抗体,其抗体类型分别为IgG1和IgG2a。A5E8和C3B6单克隆抗体有较高特异性,与多种其它细菌蛋白不发生免疫反应,对rvvhA及创伤弧菌GTC333株和WZ01株蛋白的ELISA检测阳性的效价可达1∶4000~1∶8000、免疫双扩散效价为1∶4~1∶8,Western Blot结果显示此等单克隆抗体均能有效识别rvvhA。结论本研究成功地获得了2株稳定分泌rvvhA特异性单克隆抗体的鼠源性杂交瘤细胞株,rvvhA单克隆抗体可用于检测自然表达的创伤弧菌溶细胞素。     

创伤弧菌败血症致死一例

患者女 ,5 0岁 ,因右下肢肿胀、疼痛伴发热 2 0ｈ ,皮肤出现黑紫色水泡 8ｈ ,急诊入院。体检 :中度昏迷 ,心率 86次 /ｍｉｎ ,血压 85 / 5 0ｍｍＨｇ ,呼吸浅弱 ,心肺听诊 (- ) ,腹平软 ,肝脾未及 ,颈无抵抗 ,病理征 (- ) ;右下肢高度肿胀 ,皮肤紧绷 ,见大小不一黑紫色水泡 ,部分融合成大泡 ,皮肤表皮剥脱渗血水 ,足底呈苍白色 ,足背动脉搏动消失 ;左下肢轻度肿胀 ,可见数个黑紫色小水泡 ,边缘呈暗红色 ,左足背动脉搏动也消失 ;双上肢末端发绀较苍白 ,左侧桡动脉搏动消失。入院后病情进行性恶化 ,血压下降甚至测不出 ,急测血尿素氮 10 .1ｍ…     

创伤弧菌败血症四例

创伤弧菌 (ＶＶ)败血症起病急剧、病情凶险 ,在我国大陆少见报道 ,而沿海地区陆续有散发病例出现 ,现将我院收治的 4例报告如下。例 1　 女 ,5 0岁。有血白细胞减少 [(3 0～ 3 2 )× 10 9/Ｌ]史。因右下肢肿胀、疼痛伴发热 15ｈ ,皮肤出现黑紫色水泡3ｈ在当地救治 ,但病情进行性恶化 ,5ｈ后于 2 0 0 0年 9月 11日 3∶ 0 0转入我院。体检 :中度昏迷 ,ＢＰ 85 / 5 0ｍｍＨｇ(1ｍｍＨｇ =0 133ｋＰａ ) ,呼吸浅弱 ,颈稍抵抗 ;右下肢高度肿胀 ,皮肤紧绷 ,见大小不一黑紫色水泡 ,部分融合成大泡 ,皮肤表皮剥脱而渗血水 (图 1) ,足底呈苍白色 ,足…     

肝硬化并创伤弧菌感染1例报告

慢性肝病并发创伤弧菌感染近年来引起沿海国家的重视,但报道较少。我科近期收治原发性创伤弧菌败血症1例,报告如下。     

日本鳗鲡混合感染迟缓爱德华氏菌与创伤弧菌的分离与鉴定

目的对日本鳗鲡混合感染迟缓爱德华氏菌(Edwardsiella tarda)和创伤弧菌(Vibrio vulnificus)的病原进行了分类鉴定。方法对两株病原菌进行了形态、API-ID32E鉴定系统和分子生物学鉴定,分别测定了菌株AnGH080301和An-GH080302的16SrRNA和HSP60基因序列,构建了系统进化树。结果按形态特征和API-ID32E鉴定系统分别初步鉴定菌株AnGH080301和AnGH080302为迟缓爱德华氏菌和创伤弧菌。菌株AnGH080301的16SrRNA基因部分序列(登录号FJ646618)与迟缓爱德华氏菌的16S rRNA基因(登录号AB050832)同源性最高,达99.7%;菌株AnGH080302的HSP60基因部分序列(登录号FJ646619)与创伤弧菌HSP60基因(登录号BA000037)的同源性最高,达99.8%。结论综合菌株的生理生化特性和分子生物学鉴定结果,可将菌株AnGH080301和AnGH080302分别鉴定为迟缓爱德华氏菌和创伤弧菌,迟缓爱德华氏菌与创伤弧菌均为人兽共患病病原,其混合感染日本鳗鲡致病的报道尚属首次。     

交叉引物恒温扩增技术检测创伤弧菌的应用研究

目的 建立一种快速检测创伤弧菌(Vibrio vulnificus)的交叉引物恒温扩增(cross priming amplification,CPA)技术。方法 针对创伤弧菌vvhA基因序列保守区域设计CPA引物和探针,并优化反应体系和反应条件,同时验证方法的灵敏度和特异性。结果 对创伤弧菌的检测具有高度特异性;对创伤弧菌菌液检测的灵敏度达到了1.28×10³ CFU /mL,此法 40～60 min 内即可完成检测。利用CPA法针对本实验室前期研究的CB型、EA型、CAB型、CA型和EB型等亚型创伤弧菌毒株计算特异性和敏感性,5种亚型中除了CB亚型特异性和敏感性为95.65%和100%,其余亚型特异性和敏感性均为100%。结论 本研究建立的CPA法具有较高的特异性和灵敏性,可有效缩短检验时间提高检验效率。     

创伤弧菌的药物敏感性

目的创伤弧菌(Vibrio vulnificus)是"人鱼共患病"的重要致病菌,从患"腐皮病"卵形鲳鲹(Trachinotus ovatus)鱼中分离到创伤弧菌TO-3,以阿莫西林等44种药物进行敏感性试验。结果对青霉素类抗菌药物不敏感,对头孢菌素类等抗菌药物很强的耐药性,而对氟哌酸、头孢氯氨苄、氟嗪酸、米诺环素、呋喃妥因、复达欣、萘啶酸、四环素、庆大霉素等抗菌药物高度敏感。在17味中草药中对五倍子、诃子、黄连、石榴皮等中草药极为敏感。     

创伤弧菌基因组学研究进展

创伤弧菌是人类三大致病弧菌之一,能够通过食源性传播或者伤口感染导致发病,近年来全球发病率逐步升高。随着新一代测序技术的发展,已有上百株创伤弧菌全基因组序列在国际公共数据库公布。这些数据为创伤弧菌基因组学研究提供了重要基础,并促进了对该病原菌遗传多样性、传播和致病机制的认识。本文从基因分型、种群结构和重要毒力因子3个方面对创伤弧菌基因组学研究进展进行归纳总结,以期为创伤弧菌感染、进化和防控研究提供借鉴。     

创伤弧菌溶细胞素基因在大肠杆菌中的表达及溶血活性鉴定

目的用大肠杆菌表达系统表达创伤弧菌溶细胞素,并对其溶血活性进行评价。为今后的免疫学活性研究和单克隆检测试剂盒的研发奠定基础。方法构建pET28a( )-vvhA表达载体,对包涵体进行三步洗涤后,用金属亲合层析(HisTag)纯化重组蛋白,并用溶血试验验证重组蛋白活性。结果用基因工程的方法成功获得高表达、高纯度(纯度≥96%)重组蛋白VVC。利用兔红细胞溶血试验检测表明,重组蛋白具有溶血活性,其活性为0.2μg/HU。结论成功用大肠杆菌表达系统表达创伤弧菌溶细胞素并对其纯化、复性条件进行优化。     

创伤弧菌FJ03-X2株培养条件的优化研究

目的探讨创伤弧菌毒株FJ03 X2的优化培养。方法以创伤弧菌毒株FJ03 X2进行实验,研究摇瓶培养温度、接种量、培养基、初始pH值、溶解氧等因素对菌株生长的影响,确定最适培养条件为：TSB培养基初始pH值为7.0,适宜接种量10%,培养温度28℃,装液量25mL/250mL,转速180r/min。培养菌数可达8×109cfu/mL,生物量为25mg/mL。以TSB为基础培养基,采用单因子和正交实验相结合的方法,确定最佳培养基主要成份为：葡萄糖0.2%、胰蛋白胨1.8%、大豆胨0.4%和玉米浆0.4%。以最佳培养基配方给菌体提供营养,在最适培养条件下培养,可以使培养液中的细菌生物量高达50mg/mL以上。结果得出创伤弧菌FJ03 X2的优化培养条件和培养基配方。结论国内首次优化鳗源创伤弧菌培养条件,并给出相关依据。     

Ecological diversification reveals routes of pathogen emergence in endemic Vibrio vulnificus populations

Pathogen emergence is a complex phenomenon that, despite its public health relevance, remains poorly understood. Vibrio vulnificus, an emergent human pathogen, can cause a deadly septicaemia with over 50% mortality rate. To date, the ecological drivers that lead to the emergence of clinical strains and the unique genetic traits that allow these clones to colonize the human host remain mostly unknown. We recently surveyed a large estuary in eastern Florida, where outbreaks of the disease frequently occur, and found endemic populations of the bacterium. We established two sampling sites and observed strong correlations between location and pathogenic potential. One site is significantly enriched with strains that belong to one phylogenomic cluster (C1) in which the majority of clinical strains belong. Interestingly, strains isolated from this site exhibit phenotypic traits associated with clinical outcomes, whereas strains from the second site belong to a cluster that rarely causes disease in humans (C2). Analyses of C1 genomes indicate unique genetic markers in the form of clinical-associated alleles with a potential role in virulence. Finally, metagenomic and physicochemical analyses of the sampling sites indicate that this marked cluster distribution and genetic traits are strongly associated with distinct biotic and abiotic factors (e.g., salinity, nutrients, or biodiversity), revealing how ecosystems generate selective pressures that facilitate the emergence of specific strains with pathogenic potential in a population. This knowledge can be applied to assess the risk of pathogen emergence from environmental sources and integrated toward the development of novel strategies for the prevention of future outbreaks.

The emergence of human pathogens is one of the most concerning public health topics of modern times (1–4). According to the World Health Organization, over 300 emerging infectious diseases have been reported in the 1940 to 2004 period, a trend that has continued steadily with recent outbreaks of Ebola in West Africa, Cholera in Yemen, and the global pandemic caused by COVID-19 (3–5). Even though classical molecular approaches have advanced our understanding of bacterial pathogenesis, to date, the genetic adaptations and ecological drivers that facilitate selected strains within a species to emerge as pathogens and successfully colonize the human host remain poorly understood. Given the magnitude and complexity of this urgent threat, it is critical to develop tractable organismal model systems and theoretical frameworks that allow us to dissect the molecular adaptations and environmental factors that lead to the emergence of such human pathogens.Vibrio vulnificus, an emergent human pathogen, is one of the leading causes of non-Cholera, Vibrio-associated deaths globally (6). Despite being a natural inhabitant of estuarine, coastal, and brackish waters (7), this flesh-eating bacterium has gained particular notoriety as one of the fastest killing pathogens (8, 9). Humans are typically infected with V. vulnificus through ingestion of contaminated raw seafood or by direct exposure of open wounds to seawater (6). V. vulnificus infections often result in fulminant septicaemia with an alarming mortality rate exceeding 50% (6, 10–13). The bacterium is particularly lethal in some susceptible hosts, such as immunocompromised patients or those with alcohol-associated liver cirrhosis, diabetes mellitus, or hemochromatosis (14). The annual case counts of V. vulnificus infections have steadily increased over the past 20 y in the United States (15). An upsurge in its worldwide distribution over the past three decades, in correlation with climate change, has led to disease outbreaks in regions with no history of V. vulnificus infections (16–18). Furthermore, models predict this trend to continue resulting in a steady expansion of its geographical range and the subsequent increased risk of human infections (16, 19–21).Based on a series of biochemical and phenotypic traits, V. vulnificus strains have been historically classified into three Biotypes (BT): BT1, which is mostly associated with human infections (22, 23), BT2, which is primarily pathogenic to eels (24, 25), and BT3, which is geographically restricted to Israel and possesses hybrid characteristics from BT1 and BT2 (26, 27). In contrast to Vibrio cholerae, in which all strains capable of causing cholera belong to a single clade, genomic comparisons of V. vulnificus reveal a more complex pattern in the distribution of its clinical strains (28–30). Phylogenomic analyses indicate that the population of V. vulnificus is composed of four distinct groups or clusters (Cluster 1 to 4), which largely overlap with the classical BT classification system (23, 26, 28, 31, 32). Our analyses indicate that the two largest clusters, C1 and C2, exhibit high genomic divergence and appear to be speciating (28), with clinical strains from BT1 predominantly belonging to C1 (22, 23), whereas strains from C2 are primarily associated with BT2 (6, 24, 25). C3 is highly clonal and fully overlaps with BT3, and the rare C4 contains only four nonclonal strains and belongs to BT1 (28, 31). Interestingly, despite patients showing conserved clinical symptoms, C1 clinical strains arise from different clades within the cluster, suggesting independent emergence events of this deadly pathogen (28, 31, 32). To date, the unique genetic traits that allow certain C1 strains to cause severe septicemia remain mostly unknown, posing a daunting public health risk as it hinders our ability to detect potentially pathogenic V. vulnificus (33).Recently, using a combination of bioinformatic and phenotypic analyses that surveyed more than 100 strains of V. vulnificus, we determined that V. vulnificus C1 appears to be associated with a unique ecological lifestyle or ecotype (28). Nonetheless, to date, the ecological drivers that lead to the emergence of clinical V. vulnificus C1 and their pathogenic traits remain poorly understood. In order to start untangling the complex in-situ interactions between genotypes and the environment that underlie the emergence of clinical strains, in this study, we recently surveyed a large estuary in eastern Florida, the Indian River Lagoon (IRL), where outbreaks of the disease frequently occur (7, 34). We found endemic populations of V. vulnificus in the estuary and established two sampling locations to study the environmental dynamics of this bacterium in several natural reservoirs such as water, sediment, oysters, and cyanobacteria. Interestingly, the two sampling sites show major differences in the distribution of V. vulnificus clusters. One of them, Feller’s house (Site A), appears to be significantly enriched with C1 strains, whereas in the second sampling site, Shepard Park (Site B), we mostly recovered strains from C2. Genomic analyses of these strains indicate that, despite these major differences in distribution, high recombination rates as well as frequent exchange of mobile genetic elements and virulence factors between these V. vulnificus populations occur. Microdiversity analyses of these genomes revealed unique genomic markers among C1 strains in the form of clinical-associated alleles (CAAs) with a potential direct role in virulence. The isolated V. vulnificus strains are resistant to numerous commonly used antibiotics irrespective of cluster or site of isolation. However, phenotypic analyses indicate that strains from Site A exhibit traits associated with clinical outcomes, including the ability to resist serum and catabolize sialic acid, unlike those from Site B. Finally, metagenomic and physicochemical analyses of the sampling sites indicate that this marked cluster distribution is strongly associated with distinct biotic and abiotic factors (e.g., salinity, nutrients, or biodiversity) revealing how ecosystems might generate selective pressures that facilitate the emergence of specific strains in a population with pathogenic potential.     

植物乳杆菌DOMLa对创伤弧菌诱导炎症反应的抑制作用

目的 观察植物乳杆菌DOMLa对创伤弧菌诱导小鼠腹腔巨噬细胞产生细胞因子和细胞毒作用的影响,探讨其在协助机体抵抗细菌感染以及对过强炎性反应的影响。方法 选择合适剂量的创伤弧菌感染小鼠腹腔巨噬细胞,同时加入不同剂量的植物乳杆菌DOMLa共培养。作用3 h后,采用乳酸脱氢酶释放法检测细胞毒作用,酶联免疫吸附试验检测相关细胞因子的释放量。结果 在MOI=100时,植物乳杆菌DOMLa显著降低创伤弧菌的细胞毒作用,明显抑制了创伤弧菌诱导的三种促炎细胞因子IL-6、IL-1β、TNF-α的产量。结论 植物乳杆菌DOMLa可降低创伤弧菌对小鼠腹腔巨噬细胞的细胞毒作用,并可减轻病原菌诱导巨噬细胞的过强炎症反应。该植物乳杆菌对宿主免疫细胞的其他作用和影响还有待进一步研究。