葡萄球菌肠毒素B基因的PCR快速检测法

目的 建立快速检测葡萄球菌肠毒素B(staphylococcal enterotoxin B,SEB)基因的聚合酶链反应(PCR)方法.方法 ①根据SEB基因的序列,设计PCR引物特异性扩增靶基因片段.通过对1株产SEB金黄色葡萄球菌和9株对照菌株进行PCR检测,评价该方法的特异性;通过对产SEB金黄色葡萄球菌菌株做10倍系列稀释后进行PCR检测,评价该方法的敏感性;②分析30株金黄色葡萄球菌SEB基因的携带情况.结果 ①建立PCR方法快速检测SEB基因,扩增产物长度为494 bp.PCR反应体系中有26 CFU的产SEB金黄色葡萄球菌即可检出SEB基因;②30株分离的金黄色葡萄球菌中有2株携带有SEB基因.结论 PCR法可以快速、敏感地检测SEB基因,为金黄色葡萄球菌食物中毒诊断提供依据.     

多重PCR快速检测金黄色葡萄球菌四型肠毒素基因的研究

[目的]建立一种快速、高效地检测金黄色葡萄球菌SEA、SEB、SEC和SED基因的多重PCR法并进行优化. [方法]试剂盒提取产肠毒素金黄色葡萄球菌基因组DNA作为模板,根据SEA、SEB、SEC和SED肠毒素基因片段保守区序列设计引物,多重PCR扩增产肠毒素金黄色葡萄球菌基因组中特异靶序列.对反应体系Mg2+浓度、引物浓度和退火温度进行优化,并初步检测方法特异性. [结果]在PCR反应体系中加入设计的4对引物可同时扩增出金黄色葡萄球菌四型肠毒素基因中的特异序列;在总体积为25 μl的反应体系中,最优Mg2+浓度为2.0 mmol/L,引物浓度分别为0.2 μmol/L,退火温度为49℃;以大肠杆菌O157:H7和肠炎沙门菌510041基因组DNA为模板扩增不出特异片段. [结论]成功建立金黄色葡萄球菌四型肠毒素基因多重PCR法,该法能快速、高效地同时检测SEA、SEB、SEC和SED基因,比传统PCR方法省时省力,可以弥补传统PCR法的不足.     

金黄色葡萄球菌肠毒素基因的分型和分布

目的：建立金黄色葡萄球菌肠毒素基因的检测方法。初步研究生牛奶中金黄色葡萄球菌肠毒素基因的分布状况。方法：应用PCR扩增经分离鉴定的金黄色葡萄球菌肠毒素基因SEA-SEJ，电泳检测扩增结果。结果：建立了金黄色葡萄球菌肠毒素基因PCR检测方法。从生牛奶中分离的29株金黄色葡萄球菌检测到SEA-SED和SEG-SEJ基因，没有检测到SEE基因。毒素基因携带率为65．5％，同时携带2种及以上毒素基因的菌株占37．9％。有SEA基因的占51．7％。含其它传统的毒素基因类型SEB、SEC、SED和SEE基因的菌株只占17．2％，携带新发现的毒素基因SEG、SEH、SEI和SEJ的菌株占41．4％。结论：建立的PCR检测金黄色葡萄球菌的肠毒素基因的方法可用于金黄色葡萄球菌肠毒素基因分型和分布的研究。研究表明，生牛奶中分离的金黄色葡萄球菌带毒率高，而且携带新发现的肠毒素基因的较多。     

大肠埃希菌耐喹诺酮类药物回旋酶基因突变的研究

目的 研究导致大肠埃希菌DNA回旋酶A亚单位的基因变异耐喹诺酮类药物的机制。方法 收集3株大肠埃希菌耐药菌株及1株敏感株，用PCR方法扩增其回旋酶(gyraseA)基因，对扩增片段进行单链构象多态性分析(PCR--SSCP)及DNA序列分析。结果 PCR—SSCP发现3株耐药株其DNA单链与标准株及临床敏感株迁移率不同，3株耐药菌株存在Ser—83→Leu，Asp—87→Asn及His—184→Asn突变，Ser—83→Leu及Asp—87→Asn突变位于氟喳诺酮类药物耐药决定区，gyrA基因碱基552位点C→A碱基突变致组氨酸突变为天冬酰胺。结论 大肠埃希菌对氟喹诺酮类药物产生耐药性与gyrA基因点的突变有关。     

PCR检测金黄色葡萄球菌肠毒素C基因的研究

目的建立一种检测金黄色葡萄球菌肠毒素C的快速敏感PCR方法。方法根据金黄色葡萄球菌肠毒素C基因编码序列,设计1对PCR引物来特异性扩增靶基因片段,片段长度为600 bp,通过对1株金黄色葡萄球菌产肠毒素C菌株和5株非金黄色葡萄球菌产肠毒素C菌株进行检测来评价该方法的特异性;对金黄色葡萄球菌产肠毒素C菌株做一系列10倍稀释后进行PCR检测,并对其进行敏感性分析,对PCR扩增产物进行电泳和测序鉴定。结果1株金黄色葡萄球菌产肠毒素C菌株PCR扩增反应呈阳性,5株非金黄色葡萄球菌产肠毒素C菌株PCR扩增反应为阴性;通过基因测序证实了PCR产物的特异性;PCR检测金黄色葡萄球菌肠毒素C基因的检测下限为1.5×10^2cfu/ml。结论本研究建立了一个快速、特异、敏感的金黄色葡萄球菌肠毒素C基因PCR检测方法。     

多重PCR检测金葡菌肠毒素基因型的研究

目的 应用多重聚合酶反应(PCR)，建立检测金黄色葡萄球菌肠毒素(SE)基因方法。方法 用溶菌素和蛋白酶K制备模板DNA，用多重聚合酶链反应扩增的方法，对临床分离的金黄色葡萄球菌130株进行扩增。结果 金黄色葡萄球菌肠毒素血清型A(SEA)阳性的占23．1％(30／130)，血清型B(SEB)阳性的占43．1％(56／130)，血清型C(SEC)阳性的占11．6％(15／130)，血清型D(SED)阳性的占6．12％(7／130)，血清型EA(SEE)阳性的占2．31％(3／130)；femA基因片段在多重PCR中作为内部参照避免了假阴性结果的出现。结论 多重PCR技术检测金黄色葡萄球菌肠毒素基因型，具有敏感、快速、特异的特点，是一种可靠的实验诊断手段。     

耐环丙沙星鲍氏不动杆菌的gyrA基因及parC基因突变分析

目的 研究本地区临床分离鲍氏不动杆菌环丙沙星耐药表型与DNA旋转酶A亚单位gyrA基因及拓扑异构酶Ⅳ parC基因突变的关系。方法收集28株耐药株及2株敏感株，通过PCR扩增其gyrA基因及parC基因，并对扩增产物进行限制性片段长度多态性分析（PCR-RFLP）及DNA序列分析。结果敏感株的gyrA基因产物经HinfⅠ酶切后可产生两个片段，耐药株则产生1个片段；而parC基因产物经Hinf Ⅰ酶切后，敏感株及耐药株均产生两个片段；DNA测序显示，5株耐药株gyrA基因存在Ser83→Leu及Ala88→Thr突变，其中Ser83→Leu的突变是导致Hinf Ⅰ酶切位点消失的原因，而1株敏感株无突变；1株敏感株与1株耐药株的pcrC基因存在Ser108→Ile突变，另外14株耐药株存在多位点同义突变。结论与parC基因相比，gyrA基因突变是鲍氏不动杆菌对环丙沙星耐药的主要分子基础，环丙沙星的高水平耐药可能需要多种不同的突变。     

金黄色葡萄球菌肠毒素D产毒基因的序列分析

目的：构建金黄色葡萄球菌肠素D（SED）毒力蛋白基因重组表达质粒。方法 根据SED已知序列，设计合成一对引物，用PCR方法从金黄色葡萄球毒力质粒上扩增出基因片段，克隆到原核表达质粒PET32中，转化大肠埃希菌JM109感受态细胞，经酶切和PCR鉴定，然后进行测序。结果 PCR扩增产物大小为317bp；重组质粒经双酶切和PCR鉴定表明已正确重组，测序结果与已知序列基本吻合，结论 国内首次克隆了金黄色葡萄球菌肠毒素D产毒基因，为下一步研究发病机制奠定基础。     

多重PCR技术在检测食源性金黄色葡萄球菌 肠毒素基因中的应用

摘要:目的　金黄色葡萄球菌A、B、C、D和E型肠毒素是引起食源性疾病的主要类型,采用多重PCR技术分析食源性金黄色葡萄球菌分离株肠毒素基因携带状况。方法　以19株食源性金黄色葡萄球菌分离株为研究对象,利用多重PCR技术对核酸酶基因以及肠毒素A、B、C、D和E型基因进行检测。结果　19株菌中均检出金黄色葡萄球菌特异性核酸酶基因,与传统菌落分离培养鉴定结果一致;9株菌含肠毒素SEA基因,1株同时含SEA和SEB基因,没有检测到肠毒素C、D和E基因。结论　在19株食源性金黄色葡萄球菌分离株中,10株携带肠毒素基因,以携带肠毒素A基因为主。     

PCR检测金黄色葡萄球菌肠毒素A、E基因

目的 建立一种用PCR快速敏感地检测金黄色葡萄球菌肠毒素A、E的方法.方法 根据genebank报道的编码金黄色葡萄球菌肠毒素A、E的基因序列,设计一对特异性引物来扩增靶基因片段,长度为327 bp,通过对金黄色葡萄球菌产肠毒素A、E菌株和14株非金黄色葡萄球菌产肠毒素A、E菌株进行检测,评价该方法的特异性;对金黄色葡萄球菌产肠毒素E菌株做系列10倍稀释,进行PCR检测,对其敏感性进行分析;PCR扩增产物进行电泳和测序鉴定.结果 金黄色葡萄球菌肠毒素A、E菌株出现PCR扩增反应,14株非金黄色葡萄球菌产肠毒素A、E菌株没有出现PCR扩增反应,通过测序分析证实了PCR产物的特异性;PCR检测金黄色葡萄球菌肠毒素E基因的检测下限为120 cfu/ml.结论 建立了一个快速、特异、敏感的金黄色葡萄球菌肠毒素A、E基因的PCR检测方法,可用于金黄色葡萄球菌肠毒素的临床诊断和食品安全监测.     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.