我国鱼类病原——嗜水气单胞的耐药性研究

采用琼脂扩散法和稀释法研究26株嗜水气单胞菌对21种菌药物的敏感性,分析了其耐药状况。结果表明：从不同地区分离收集到的26株嗜水气单胞菌（Aeromonas hydrophila）对青霉素类和头孢菌素类药物全部具耐药性,对万古霉素多数不敏感。21种药物中最敏感的是氟哌酸、氯霉素、呋喃呋酮,总体耐药率分别为7.7％、7.7％和11.5％。氨基糖甙类药物和四环素类药物的耐药频率介于其间,对磺胺药的耐药菌比例也很高,高达73.1％的A.hydrophila对磺胺及复方磺胺其有耐药性,但耐磺胺比耐复方磺胺的现象更为普遍,对3种常用药物具有耐药性的菌株比例最高。同时对鱼类病原菌耐药性的判定标准以及两种方法在鱼类病原菌耐药性研究中的适用性问题进行了讨论。     

139株空肠弯曲菌耐药性分析

空肠弯曲菌(Campylobacter jejuni)是最常见的食源性病原菌之一。本研究采用微量肉汤稀释法对分离得到的139株空肠弯曲菌(117株为禽源样本分离株,22株为人源样本分离株)进行耐药性检测。通过对最小抑菌浓度(MIC)的判定结果得出:120株(86. 33%)空肠弯曲菌分离株对6类9组临床常用的抗生素表现出不同程度的耐药,其中禽源空肠弯曲菌耐药率为83. 76%,22株人源空肠弯曲菌均表现出耐药性。对喹诺酮类抗生素表现出高度耐药(环丙沙星80. 58%,萘啶酸77. 70%);对四环素类表现为中等耐药(四环素53. 24%);对部分大环内酯类、氨基糖苷类、林可酰胺类表现为低耐药(庆大霉素7. 19%,阿奇霉素5. 76%,克林霉素6. 47%);对酰胺醇类、部分大环内酯类表现为敏感(氟苯尼考0%,红霉素0%、泰利霉素0%)。139株空肠弯曲菌共产生14种耐药谱型,以TET-CIP-NAL谱型最多,占比38. 13%,耐三重及以上抗生素的多重耐药菌株占比53. 24%。禽源菌株中多重耐药占比46. 15%,人源菌株中多重耐药占比90. 91%。研究结果显示空肠弯曲菌耐药现状不容乐观,尤其对喹诺酮类与四环素类抗生素耐药性较为突出,且过半数菌株为多重耐药。本研究为食源性空肠弯曲菌的防控及临床用药提供参考。     

大肠杆菌四环素耐药基因表达与耐药水平的相关性

为了探索大肠杆菌耐药基因的表达与耐药水平的关系,本研究通过微量肉汤稀释法检测240株大肠杆菌对土霉素(terramycin, OTC)、金霉素(aureomycin, CTC)、四环素(tetracycline, TC)、多西还素(doxycycline,CAS)和米诺环素(minocycline, MINO) 5种四环素类抗菌药物的敏感性,采用PCR方法检测四环素类耐药基因tet B和tet X的携带情况,通过荧光定量PCR法考察不同四环素浓度对tet B表达的影响。研究结果表明:240株猪源大肠杆菌对土霉素、金霉素、四环素、多西还素和米诺环素的耐药率分别为93.33%、92.92%、92.50%、80.42%和37.08%,兽用四环素类药物的治疗效果难以保证;四环素耐药基因的携带率较高,tet B和tet X检出率分别为22.92%和85.00%;Tet B基因mRNA的表达量随着四环素浓度升高而逐步增强,说明tet B属于诱导表达基因,耐药菌难以通过停止用药来恢复对四环素的敏感性,研究人员建议兽医临床应将四环素类药物作为二线药物使用。     

转座子Tn916对固氮螺菌Azospirillum brasilense的接合诱变及氨分 …

以携带质粒ｐＡＭ１２０（Ａｐ＾ｒ,Ｔｃ＾ｒ／Ｔｎ９１６）的大肠杆菌（Ｅ．ｃｏｌｉ ＣＧ１２０）为供体菌株,与受体菌巴西固氮螺菌采用膜接合法进行接合转移,在选择平板上得到具较高频率的接合子（１０＾－５／每个供体菌,选择四环素抗性）。从８４６株四环素抗性接合子中进一步用奈氏法筛选得到氨分泌突变株３株。在无氮培养基上,其氨分泌量可达７．５￣１４．０ｍｍｏｌ／Ｌ。用乙炔还原法分析氨分泌突变株在不同浓度氮源     

一株四环素高效降解菌的分离及降解特性

四环素类抗生素在养殖业中广泛使用引起药物残留,给环境及人类健康带来了深远影响。从利用四环素类抗生素作为饲料添加剂的养猪厂底泥中,筛选获得一株能够高效降解四环素的细菌XY-1,经革兰氏染色、形态学观察、生理生化及16S rDNA序列分析等,确定该菌株属于拉乌尔菌属,命名为Raoultella sp.XY-1。采用高效液相色谱(HPLC)测定了菌株XY-1对四环素的降解能力,结果表明,该菌株最佳降解条件是温度为25℃,初始pH值为7.0,在此最佳条件下,XY-1在第8天时生长量最大且四环素降解率最高达到70.68%。对XY-1的四环素耐药基因进行了初步探究,首次在该菌株中检测到两种四环素耐药基因tet(D)和tet(E)。     

大连市伤寒沙门菌耐药性及耐药基因分析

目的检测多重耐药伤寒沙门菌对抗菌药物的敏感性及其耐药基因携带情况,为伤寒沙门菌引起的腹泻治疗提供科学依据。方法采用微量肉汤稀释的方法测定大连地区临床分离的78株伤寒沙门菌对12种抗生素的敏感性;用PCR方法检测TEM型β内酰胺酶基因、catA和catB氯霉素乙酰基转移酶基因以及cmlA氯霉素外排泵蛋白基因、aac(6′)Ⅰb和aac3Ⅱ型氨基糖苷类修饰酶基因、qacEΔ1sul1耐消毒剂和磺胺基因、多重耐药外排基因acrB等8种耐药基因。结果78株沙门菌对12种药物有不同程度耐药(1.28%~74.35%)。得到9株多重耐药菌株,其中5株检出TEM型β内酰胺酶基因;7株耐氯霉素的伤寒沙门菌菌株中,2株仅检出catA基因,1株仅检出catB基因,1株仅检出cmlA氯霉素外排泵蛋白基因,2株同时检出catA基因和cmlA氯霉素外排泵蛋白基因;2株检出aac(6′)Ⅰb基因,1株检出aac3Ⅱ型氨基糖苷类修饰酶基因;4株检出耐消毒剂和磺胺基因qacEΔ1sul1;6株检出多重耐药外排基因acrB。结论大连地区临床分离的伤寒沙门菌存在严峻的耐药现象,多种耐药基因存在于耐药伤寒沙门菌中,可能是导致菌株对多种抗菌药物耐药的原因。     

大肠埃希菌耐药性水平传播实验研究

目的研究重症监护病房（ICU）患者标本中分离的大肠埃希菌的耐药情况以及耐药性水平传播的实验研究。方法采取双纸片法（K-B）检测细菌的耐药性;产超广谱β-内酰胺酶（ESBLs）大肠埃希菌为供体菌,耐利福平大肠埃希菌（对其他抗生素敏感）作为受体菌进行接合实验;采用聚合酶链反应（PCR）技术扩增整合子和耐药基因。结果30株大肠埃希菌中产ESBLs菌株检出率为46．7％;接合培养后,接合菌携带23kb和25kb大质粒,而无供体菌中一系列小质粒;供体菌和接合菌均携带I型整合子。结论大肠埃希菌耐药性严重,且呈多重耐药性;产ESBLs菌株可通过质粒和整合子将耐药基因转移给敏感菌,导致耐药性传播。     

小鼠造血干细胞增殖与分化性能的研究

本文选择Ｙ染色体特异的性别决定基因作为新的细胞遗传标志,采用ＰＣＲ技术研究了小鼠造血干细胞的增殖与分化性能。将雄鼠骨髓细胞输注给经致死剂量射线照射的雌性受体小鼠、ＰＣＲ测试结果表明,所有ＣＦＵ－Ｓ均为供体起源。供体来源的ＣＦＵ－Ｓ在其输入体内后,可通过增殖,分化形成各系造血细胞,但ＣＦＵ－Ｓ中的纤维母细胞和ＣＦＵ－Ｓ重建造血后受体小鼠骨髓中的纤维母细胞均为受体起源。由此可见,小鼠骨髓中的ＣＦＣ－Ｓ     

丽水市中心医院2017年临床分离菌耐药情况

摘要：目的 了解2017年丽水市中心医院临床分离病原菌的分布情况和耐药特征。方法 收集丽水市中心医院2017年全年临床分离病原菌,采用K-B纸片法及Vitek2-Compact系统进行药物敏感性试验,采用WHONET 5.6软件进行数据分析。结果 共分离到病原菌5 928株,其中革兰阳性菌1 875株（31.63%）,革兰阴性菌4 053株（68.37%）。革兰阳性菌中以金黄色葡萄球菌、凝固酶阴性葡萄球菌、屎肠球菌、粪肠球菌、肺炎链球菌为多见。革兰阴性菌中以大肠埃希菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌、流感嗜血杆菌为多见。肠杆菌科细菌对碳青霉烯类抗菌药、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、头孢西丁敏感性较高。产超广谱β内酰胺酶大肠埃希菌和肺炎克雷伯菌的检出率分别为53.5%和23.6%。鲍曼不动杆菌复合群对碳青霉烯类抗菌药、喹诺酮类、头孢吡肟的耐药率>70%。铜绿假单胞菌对阿米卡星、头孢他啶、头孢吡肟、哌拉西林/他唑巴坦的耐药率<15%。葡萄球菌属对喹诺酮类、红霉素、四环素类药物的耐药率>30%,未检到万古霉素和利奈唑胺的耐药株。耐甲氧西林金黄色葡萄球菌和凝固酶阴性葡萄球菌的检出率分别为43.6%和68.5%。结论 细菌耐药情况日益严重,特别是多重耐药及泛耐药细菌的不断增加给临床治疗带来了极大的困难,因此须定期监测细菌耐药情况以预防耐药菌的产生和传播流行。     

伤口分泌物的病原菌分布及耐药性分析

目的调查福建省龙岩市第二医院伤口分泌物病原菌的分布及耐药情况,为合理应用抗生素提供依据。方法收集2012年1月至2013年5月患者伤口分泌物标本,采用常规方法进行分离培养,用VITEK-2 Compact全自动微生物分析仪系统进行鉴定及药敏分析。结果送检503份标本,培养阳性272份,阳性率为54. 1% ;病原菌检出343株,其中革兰阴性菌189株占55. 1%,革兰阳性菌151株占44.0%,真菌3株占0.9% ;前5位的病原菌分别为金黄色葡萄球菌、凝固酶阴性葡萄球菌、铜绿假单胞菌、大肠埃希菌、鲍曼不动杆菌。耐甲氧西林金黄色葡萄球菌（MRSA）和耐甲氧西林凝固酶阴性葡萄球菌（MRCNS）的检出率分别是30.4%、82. 1%。粪肠球菌中耐高浓度氨基糖苷类肠球菌（HLAR）的检出率为55%。革兰阳性菌对万古霉素、替加环素、利奈唑胺未出现耐药菌株。铜绿假单胞菌、肠杆菌科细菌对亚胺培南的耐药率分别为5. 6%、0。大肠埃希菌中超广谱P-内酰胺酶（ESBL）的检出率是42.9%。鲍曼不动杆菌对头孢哌酮/舒巴坦的耐药率最低为25.0%,对其他抗菌药物耐药严重,多数抗菌药物的耐药率均〉45%。结论伤口感染的主要病原菌是革兰阴性菌,多重耐药菌株比例较高,临床应根据药敏结果合理选用抗生素,减少新的耐药菌株出现。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.