猪源产志贺毒素大肠埃希茵耐药性及超广谱β内酰胺酶基因型分析

目的了解我国猪源产志贺毒素大肠埃希菌（Shigatoxin-producingEscherichiacoli,STEC）产超广谱8内酰胺酶（Extended—spectruml β-lactamases,ESBLs）情况及其基因型。方法对22株分离自重庆地区2个规模化养殖场健康猪粪的STEC菌株进行药物敏感性检测、ESBLs表型确证及7种类型（blaSHV,blaLEN,blaOKP,blaTEM,blaCTX-M,blaGES及blaKPC）ESBLs基因型PCR检测和测序分析。结果22株携带stx2e的STEC菌株中2株对所有23种测试抗生素敏感,其余菌株除对亚胺培南和美罗培南敏感外,对其他抗生素均存在不同程度耐药。10株sTEc菌株（占45．45％）产ESBLs酶。PCR检测其中1株为blaCTX-M-1基因型,其余9株为blaCTX-M-9 ＋blaTEM-1基因型。结论重庆地区猪源STEC中存在较高比例的产ESBLs菌株。在加强人和动物STEC感染检测与监测的同时,应进行细菌耐药性监测。     

The recombination hot spots and genetic diversity of the genomes of African swine fever viruses

The FilmArray^Ⓡ Meningitis/Encephalitis Panel detects the 14 most frequent pathogens causing meningitis and/or encephalitis. The use of FilmArray ME with non-validated samples is seldom published in the literature. We describe the case of a 3-year-old child, diagnosed with acute meningoencephalitis, in whom the FilmArray^Ⓡ ME technique successfully identified Neisseria meningitidis in both skin biopsy and whole blood samples.     

西藏藏族结核分枝杆菌临床分离株的MIRU-VNTR基因多态性分析与评价

目的 了解西藏地区藏族人群中结核分枝杆菌24位点MIRU-VNTR的基因多态性及其评价.方法 应用欧盟推荐的24位点MIRU-VNTR分型方法,将本次分型结果与MIRU-VNTRplus数据库进行比对,并应用BioNumerics5.0软件进行聚类分析.结果 577株结核分枝杆菌分为347种基因型,其中299株分为69个基因簇,另278株表现为独特的基因型.MIRU31、Qub11b2、Qub26、Qub4156c、Mtub21、MIRU20和MIRU26七个位点对西藏地区藏族人群中结核分枝杆菌临床分离株的分辨力较高,另17个位点的分辨力较低,其中MIRU24位点分辨率为0.结论 西藏地区藏族人群中结核分枝杆菌MIRU-VNTR分型具有良好的多态性,且该地区以现代型结核分枝杆菌为流行优势菌.     

广东省2009－2013 年霍乱弧菌病原学特征分析

目的 分析广东省2009－2013 年霍乱病例及环境来源O1/O139 群霍乱弧菌病原学特征。方法 选取2009－2013 年广东省霍乱病例来源、环境（水体和海水产品）来源的O1/O139群霍乱弧菌。采用血清分型、抗菌药物敏感性试验、毒力基因PCR 检测和脉冲场凝胶电泳（PFGE）分子分型方法 , 研究不同来源的霍乱弧菌血清型、抗菌药物敏感性、毒力基因携带以及分子分型方面的异同。结果 2009－2013 年广东省共分离得到各类来源O1/O139 群霍乱弧菌190株（病例16 株, 外环境174 株）。病例来源菌株分为O1 群稻叶型（3 株）、小川型（7 株）和O139 群（6株）3 种菌型;其中10 株ctxA 基因阳性, 2 株小川型菌株携带不完整CTXΦ噬菌体;5 株菌对11 种抗菌药物完全敏感, 3 株对4 种抗菌药物表现出耐受。外环境来源菌株中53 株稻叶型, 22 株小川型和2 株O139 群菌株携带不完整CTXΦ噬菌体;2 株O139 菌株检出ctxA 基因阳性;25 株对≥4 种抗菌药物耐受, 其中有2 株同时对11 种抗菌药物中的7 种耐受, 以水产品中的稻叶型菌株为主（13株）。PFGE分子分型结果显示, 菌株经NotⅠ酶切后的PFGE型别表现出明显的多样性。稻叶型和O139 群病例菌株的带型聚集在同一个聚类中, 小川型病例菌株带型分散在不同的聚类中, 病例来源菌株与环境来源菌株的带型差别较大。结论 广东省O1/O139 群霍乱弧菌毒力基因和遗传特征复杂多样, 菌株多重耐药形势严峻, 需要加强菌株型别变异及耐药监测。     

Discussions and decisions of the 2012–2014 International Committee on Taxonomy of Viruses (ICTV) Filoviridae Study Group,January 2012–June 2013

The International Committee on Taxonomy of Viruses (ICTV) Filoviridae Study Group prepares proposals on the classification and nomenclature of filoviruses to reflect current knowledge or to correct disagreements with the International Code of Virus Classification and Nomenclature (ICVCN). In recent years, filovirus taxonomy has been corrected and updated, but parts of it remain controversial, and several topics remain to be debated. This article summarizes the decisions and discussion of the currently acting ICTV Filoviridae Study Group since its inauguration in January 2012.     

Weil's disease (leptospirosis) manifesting as fulminant hepatic failure: Report of an autopsy case

We report an autopsy case of a 60-year-old man with Weil's disease who died of fulminant hepatic failure. Ante-mortem blood culture yielded the growth of Leptospira interrogans (serovar icterohaemorrhagiae). At autopsy, the liver weighed 1210 g and showed a typical appearance of “acute yellow liver atrophy”. Zone 3 (centrilobular region) showed submassive necrosis of hepatocytes accompanied by marked hemorrhage. Hepatocytes in zones 1 and 2 were well preserved, and the leptospira antigen was immunohistochemically demonstrated in several hepatocytes. Dissociation of liver cell plates was not observed. An immunohistochemical study demonstrated that CD31-positive, sinusoidal endothelial cells had almost completely disappeared in zone 3. This finding suggested that severe and selective damage to endothelial cells in zone 3 was the main cause of the submassive hepatocellular necrosis, which led to fulminant hepatic failure in the present case.     

麦氏弧菌多位点序列分型方法的建立与应用

目的建立针对麦氏弧菌的多位点序列分型（MLST）方法,评价该方法的分型效果,并对收集的麦氏弧菌进行MLST分析。方法筛选出7个管家基因（ftsZ、gapA、mreB、gyrB、purM、recA、ropA）,设计特异引物,在17株麦氏弧菌中PCR扩增管家基因序列。 用DnaSP 6.12.03软件和Split tree 4.0软件评价基因多态性、中性进化和基因重组情况;根据7个管家基因的序列差异获得对应的序列分型（ST）型别,用BioNumerics 7.1软件对不同ST型别构建最小生成树和聚类图,并用eBURST 3.0软件计算克隆复合体（CCs）。结果所选的管家基因具有足够多的等位基因位点、序列差异和足够高的分辨率;7个管家基因的Split tree对所有麦氏弧菌的聚类一致;中性试验结果显示,7个管家基因在进化过程中受遗传漂变的影响较小。 MLST将17株麦氏弧菌分成14个ST型别,大多数菌株（64.70%）均单独形成一个ST型别,其中ST007形成了可能的优势克隆群。 这些菌株之间存在相对较远的遗传距离,在垂直传播上呈现出潜在的地域聚集性。结论本研究建立的麦氏弧菌的MLST方法能分析麦氏弧菌的种群结构和遗传进化关系。     

基于CRISPR/Cas蛋白的副溶血弧菌检测方法的研究

目的利用规律间隔性成簇短回文重复序列（CRISPR）免疫原理及Cas12a酶的特点构建一种快速检测副溶血弧菌（VP）的方法,实现对病原菌准确快速的检测和识别。方法本研究通过制备纯化Cas12a蛋白,筛选构建VP的gRNA,建立CRISPR-VP荧光检测系统,根据最终荧光扩增曲线判定CRISPR-VP检测方法的有效性。结果在CRISPR-VP检测方法中只在VP的序列存在时才会产生明显的荧光信号。结论本实验初步建立了基于CRISPR/Cas蛋白的VP的检测方法,为后续简易检测试剂的研制提供理论依据。     

Immunogenicity and therapeutic effects of recombinant Ag85AB fusion protein vaccines in mice infected with Mycobacterium tuberculosis

The immune function of tuberculosis (TB) patients is disordered. By using immune regulators to assist chemotherapy for TB the curative effect might be improved. In this study, a vaccine containing Mycobacterium tuberculosis (M. tuberculosis) recombinant Ag85AB fusion protein (rAg85AB) was constructed and evaluated. The mice were immunized intramuscularly three times at two-week intervals with Ag85AB fusion protein combined with Corynebacterium parvum adjuvant (rAg85AB+CP). In comparison to control mice that received either CP alone or saline, the mice that received rAg85AB+CP had significantly higher number of T cells secreting IFN-γ and higher levels of specific antibodies of IgG, IgG1 and IgG2a isotypes in sera. The specific antibodies also had higher ratios of IgG2a to IgG1, indicating a predominant Th1 immune response. To test for immunotherapy of TB, M. tuberculosis infected mice were given three intramuscular doses of 20 μg, 40 μg or 60 μg of rAg85AB in rAg85AB+CP, or phosphate-buffered saline (PBS), or CP or Mycobacterium phlei (M. Phlei) F.U.36. Compared with the PBS group, 20 µg, 40 µg and 60 µg rAg85AB+CP and M. phlei F.U.36 groups reduced the pulmonary bacterial loads by 0.13, 0.15, 0.42 and 0.40 log₁₀, and the liver bacterial loads by 0.64, 0.64, 0.53 and 0.61 log₁₀, respectively. Pathological changes of lungs were less, and the lesions were limited to a certain extent in 40 µg and 60 µg rAg85AB+CP and M. phlei F.U.36 groups. These results showed that rAg85AB+CP had immunotherapeutic effect on TB, significantly increasing the cellular immune response, and inhibiting the growth of M. tuberculosis.     

Determination of relationships among non-toxigenic Vibrio cholerae O1 biotype El Tor strains from housekeeping gene sequences and ribotype patterns

Sequencing of three housekeeping genes, mdh, dnaE and recA, and ribotyping for seven non-toxigenic Vibrio cholerae O1 strains isolated from different geographic sources indicate a phylogenetic relationship among the strains. Results of MLST and ribotyping indicate a clear difference between three toxigenic strains (N16961, O395, and 569B) and three non-toxigenic strains from India (GS1, GS2, and GW87) and one Guam strain (X392), the latter of which were similar in both MLST and ribotyping, while two other non-toxigenic strains from the USA and India (2740-80 and OR69) appeared to be more closely related to toxigenic strains than to non-toxigenic strains, although this was not supported by ribotyping. These results provide clues to the emergence of toxigenic strains from a non-toxigenic progenitor by acquisition of virulence gene clusters. Results of split decomposition analysis suggest that widespread recombination occurs among the three housekeeping genes and that recombination plays an important role in the emergence of toxigenic strains of V. cholerae O1.