ESBLs大肠埃希菌和肺炎克雷伯杆菌整合子分布及其与ESBLs基因关系研究

目的研究整合子在院内感染ESBLs大肠埃希菌和肺炎克雷伯杆菌中的分布及其与细菌耐药的相关性,探讨Ⅰ类整合子在ESBLs基因水平转移中的作用及其与ESBLs基因型的关系。方法运用K-B法,纸片扩散法,PCR,接合传递试验、套式PCR、质粒谱分析及DNA测序研究携带耐药基因的Ⅰ类整合子与耐药播散的关系。结果产ESBLs和非产ESBLs菌株中Ⅰ类整合酶扩增阳性例数分别是70例（占66.7%）和22例（占22.4%）,2组整合子阳性率差异有统计学意义（P〈0.01）。整合子阳性组中ESBLs、多重耐药菌均明显高于阴性组。产ESBLs菌株中blaSHV、blaCTX和blaTEM基因与整合子经质粒共同转移的频率分别是79.3%、58.5%和45.1%。结论整合子在产ESBLs大肠埃希菌和肺炎克雷伯杆菌中的分布明显高于非产ESBLs菌株,主要为Ⅰ类整合子,并参与产ESBLs菌株多重耐药性的形成,其中blaSHV基因型与整合子经质粒共同转移的频率高于其他两类基因,提示SHV型酶在浙南地区具有更强的扩散优势。     

产ESBLs大肠埃希菌整合子及其相关基因盒的研究

目的检测产超广谱β-内酰胺酶（ESBLs）大肠埃希菌中整合子的整合酶及插入的相关基因盒情况,分析整合子对细菌耐药性的影响。方法采用K-B琼脂扩散法对45株临床分离的产ESBLs大肠埃希菌进行药敏试验;应用PCR法检测45株产ESBLs大肠埃希菌Ⅰ类、Ⅱ类和Ⅲ类整合子;对Ⅰ类整合子阳性菌进行整合子相关基因盒检测。结果45株菌中有27株（60．0％）含有Ⅰ类整合子,没有检测到Ⅱ类和Ⅲ类整合子阳性菌。在Ⅰ类整合子阳性菌中,有23株携带Ⅰ类整合子相关基因盒（85．2％）,5种不同的基因盒图谱,片段大小在600～2322bp,分离自同一科室的部分菌株携带大小相同的基因盒;Ⅰ类整合子阳性菌株的耐药率高于整合子阴性的菌株。结论Ⅰ类整合子及整合子相关基因盒在产ESBLs大肠埃希菌株中分布广泛,整合子在细菌耐药中发挥作用。     

新生儿病区产ESBLs大肠埃希菌整合子及其耐药性分析

目的 了解新生儿病区产ESBLs大肠埃希菌整合子的携带情况及其耐药性.方法 采用K-B琼脂扩散法对56株产ESBLs大肠埃希菌进行药敏试验;应用PCR法检测Ⅰ类、Ⅱ类和Ⅲ类整合子;以肠杆菌科重复序列-聚合酶链式反应(ERIC-PCR)进行基因分型.结果 56株产ESBLs大肠埃希菌的Ⅰ类整合子检出率为60.7％,未检出Ⅱ类和Ⅲ类整合子;菌株对庆大霉素、环丙沙星、左氧氟沙星、复方新诺明、头孢唑林、氨曲南、头孢他啶的耐药率差异有统计学意义(P＜0.05),阳性菌株的耐药率高于阴性菌株;56株大肠埃希菌分为45种基因型.结论 Ⅰ类整合子广泛存在于新生儿病区产ESBLs大肠埃希菌并与其耐药性相关.     

产超广谱β-内酰胺酶大肠埃希菌Ⅰ类整合子检测与耐药性关系

目的了解I类整合子在产ESBLs和非产ESBLs大肠埃希菌中分布状况,分析I类整合子在细菌多重耐药中的作用。方法用PCR方法扩增I类整合酶基因,经电泳后检测扩增产物。用2χ检验进行统计学分析,P<0.05为差异有显著性。结果105株大肠埃希菌检出I类整合子46株,检出率为43.8%。I类整合子在产ESBLs菌的检出率为53.4%,明显高于非产ESBLs菌(31.9%),2χ检验,P<0.01。I类整合子阳性菌株多重耐药率为68.8%(33/48),明显高于阴性菌株(33.3%),P<0.05。I类整合子阳性菌株和产ESBLs菌均对青霉素类、喹诺酮类、磺胺类抗生素表现出较高的耐药率。所有菌株均对亚胺培南敏感。结论I类整合子携带与产ESBLs菌株耐药有关,I类整合子阳性菌株对多种抗生素的耐药率大于整合子阴性菌株。     

外科手术切口感染大肠埃希菌的耐药性分析

目的分析外科手术切口中大肠埃希菌的感染率及耐药性,为临床合理用药提供科学依据。方法对2009年6月至2010年9月外科患者手术切口标本中分离的大肠埃希菌耐药情况进行分析,并对产超广谱β-内酰胺酶（ESBLs）菌株进行表型确证试验。结果 140株大肠埃希菌中,产ESBLs菌株的检出率为42.14%;产ESBLs菌株对一～四代头孢菌素、广谱青霉素、氟哇诺酮类及氨基糖苷类抗菌药物具有较高的耐药率;非产ESBLs菌株对青霉素类以外的抗菌药物具有较高的敏感率;产ESBLs菌株对大多数抗菌药物的耐药率明显高于非产ESBLs菌株（P〈0.05）。结论外科手术切口术后大肠埃希菌的感染较严重,且产ESBLs菌株多药耐药明显,临床应加强监测与控制。     

大肠埃希菌和肺炎克雷伯菌ESBLs检测及耐药性分析

由细菌超广谱β-内酰胺酶（ESBLs）引起的细菌耐药性一直是临床相关感染性疾病治疗中的棘手问题。从不同病区患者标本中分离了96株大肠埃希菌和80株肺炎克雷伯菌,分剐采用双纸片协同试验和药物敏感试验检测了上述菌株产生ESBLs情况及对17种抗生素的耐药性。结果发现,27．1％（26／96）的大肠埃希菌株和22．5％（18／80）肺炎克雷伯菌株产ESBLs。ICU病房分离的大肠埃希菌和肺炎克雷伯菌株ESBLs总阳性率（46．0％）与介入科病房和烧伤科病房分离菌株ESBLs总阳性率（28．6％和25．0％）无显著性差异（P〉0．05）,但明显高于呼吸科、骨科、其他病房及门诊部分离菌株ESBLs总阳性率（6．3％～14．3％,P〈0．01）。不产ESBLs大肠埃希菌株和肺炎克雷伯菌株对17种抗生素耐药率明显低于产ESBLs菌株。产ESBLs大肠埃希菌和肺炎克雷伯菌对氨曲南均敏感,对氨苄西林／舒巴坦、阿莫西林／棒酸、阿米卡星耐药率仅为15．8％-23．4％。上述实验结果提示,大肠埃希菌和肺炎克雷伯菌临床菌株中有较高的ESBLs阳性率,不同病区患者感染的大肠埃希菌和肺炎克雷伯菌ESBLs阳性率有很大差异,氨曲南、氨苄西林／舒巴坦、阿莫西林／棒酸、阿米卡星可作为治疗产ESBLs大肠埃希菌和肺炎克雷伯菌感染性疾病的首选药物。     

产超广谱β-内酰胺酶大肠埃希菌对喹诺酮类抗菌药物的耐药性检测

目的 了解临床分离产超广谱β-内酰胺酶（ESBLs）大肠埃希菌对喹诺酮类等抗菌药物的耐药性。方法 NCCLS表型确证试验（纸片增强法）检测出临床分离大肠埃希菌中产ESBLs菌株,琼脂稀释法测定产ESBLs菌株对喹诺酮类等抗菌药物的耐药性。结果 临床分离大肠埃希菌中产ESBLs菌株的检出率为40．2％（92／229）,产ESBLs菌株以尿标本多见,对6种喹诺酮类抗菌药物的耐药率均在89％以上,哌拉西林的耐药率为100％;对头孢噻肟、头孢他啶和哌拉西林-三唑巴坦的耐药率分别为77．2％、1．1％和21．7％,对亚胺培南极其敏感,耐药率为0％。结论 产ESBLs大肠埃希菌发生率较高,对喹诺酮类抗菌药物耐药显著,临床应加强检测和监测。     

大肠埃希菌和肺炎克雷伯菌对三种氨基糖苷类抗生素的耐药性分析

【摘 要】 目的 评价庆大霉素、妥布霉素及阿米卡星三种氨基糖苷类抗生素（AGs）对大肠埃希菌和肺炎克雷伯菌的体外抗菌活性。方法 对902株大肠埃希菌和404株肺炎克雷伯菌,采用VITEK-2全自动微生物分析仪配套的AST-GN13药敏卡进行庆大霉素、妥布霉素及阿米卡星的体外药敏试验。结果 大肠埃希菌和肺炎克雷伯菌的产超广谱β-内酰胺酶（ESBLs）菌株检出率分别为40.8％和36.6％;产ESBLs的大肠埃希菌对庆大霉素、妥布霉素及阿米卡星的敏感率分别为42.4%、39.1%和96.5%,与非产ESBLs菌株比较,敏感率差异均有统计学意义（P<0.01）;产ESBLs的肺炎克雷伯菌对庆大霉素、妥布霉素及阿米卡星的敏感率分别为64.2%、62.8%和91.9%,与非产ESBLs菌株比较,敏感率差异均有统计学意义（P<0.01）;阿米卡星对产与非产ESBLs的大肠埃希菌和肺炎克雷伯菌均高度敏感,敏感率均在91%以上。结论 本地区大肠埃希菌和肺炎克雷伯菌产ESBLs菌株流行严重,ESBLs的产生可使大肠埃希菌和肺炎克雷伯菌对AGs的耐药情况加重,提示ESBLs和AGs引起的耐药可能存在一定的相关性。     

临床产ESBLs大肠埃希菌整合子检测及基因型分析

了解临床分离的产ESBLs大肠埃希菌(ESBLs-producing Escherichia coli,ESBL-EC)中Ⅰ、Ⅱ、Ⅲ类整合子及ESBL-EC基因型的分布。收集2014年1月至12月某三甲医院住院患者分离的大肠埃希菌,经全自动细菌分析系统鉴定并检测其对临床常用抗菌药物的耐药性,双纸片协同试验确定ESBL-EC,采用聚合酶链反应(PCR)对整合子基因和ESBLs基因进行检测。K-B法比较整合子阳性菌株与阴性菌株的耐药率。结果发现,98株临床非重复ESBL-EC对青霉素类、头孢菌素类、喹诺酮类、单环酰胺类和庆大霉素耐药率均大于50%,对妥布霉素耐药率为31.62%,对呋喃妥因、阿莫西林/克拉维酸和阿米卡星较敏感,分别为11.11%、13.4%和6.12%;对碳青霉烯类抗菌素、替加环素和哌拉西林/他唑巴坦敏感率为100%。98株菌中检出47株含Ⅰ类整合子(47.96%),3株含Ⅱ类整合子(3.06%),所有菌株中有1株同时含Ⅰ类和Ⅱ类整合子,未检出Ⅲ类整合子。整合子阳性菌株对四环素和复方新诺明的耐药率高于整合子阴性菌株(P0.05)。98株菌中β-内酰胺酶基因TEM、CTX-M-9、CTX-M-1、CTX-M-2和SHV阳性率分别为62.24%、53.06%、32.65%、4.08%和3.06%,ESBL-EC基因分型分布以TEM合并CTX-M-9型(共30株)最多见,占30.61%。结果表明,Ⅰ类整合子在产ESBLs大肠埃希菌中分布广泛,本研究尚不足以证明整合子的存在可影响ESBL-EC菌株抗生素耐药水平。同时携带TEM和CTX-M-9基因是安徽医科大学解放军174临床学院产ESBLs大肠埃希菌临床耐药菌株产生的主要原因。     

产超广谱β-内酰胺酶大肠埃希菌的耐药性分析

目的了解杭州市第一人民医院产ESBLs大肠埃希菌的发生比例及对临床上常用的24种抗菌药物的耐药率变化.方法收集2003 2004年该院各类临床标本中分离的大肠埃希菌,采用NCCLS推荐的表型确证试验方法检测ESBLs菌株;药敏试验采用纸片扩散法.结果2003年与2004年,产ESBLs的大肠埃希菌分离率分别为46.11%（184/399）、57.44%（386/672）（P=0.0003）;2年来,ESBLs阳性菌对临床常用的24种药物表现出较高的耐药性,耐药率上升非常显著（P=0.0005）;非产ESBLs大肠埃希菌对大多数抗菌药物仍保持较高的敏感率;但2004年ESBLs阴性的大肠埃希菌的耐药性,比2003年显著上升（χ^2=37.785,P=0.0005）.结论尽早开展产ESBLs菌的监测,合理使用抗菌药物,对于有效控制产ESBLs菌的播散与流行是一项重要措施.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.