临床常见念珠菌及其体外对抗真菌药物敏感性分析

目的观察临床感染的常见念珠菌种类及其对抗真菌药物的敏感性。方法统计近1年多来临床标本分离的念珠菌,并测试其对5-氟胞嘧啶(5-Fc)、两性霉素-B(AMB)、氟康唑(FCA)、伊曲康唑(ITR)的最低抑菌浓度(MIC)。结果分离菌株中,白色念珠菌超过一半,其他依次为光滑念珠菌、热带念珠菌和克柔念珠菌。体外药敏试验表明,AMB和5-Fc对临床常见念珠菌均具有较高的敏感性。结论尽管白色念珠菌仍居首位;但非白色念珠菌也有较高比例,且耐药性较前者更高。     

假丝酵母菌属的耐药性分析

目的 了解我院深部真菌感染的种类和耐药特点,为合理使用抗真菌药物提供病原学依据.方法 对2009-2010年分离的假丝酵母菌属进行菌种分布和耐药性分析.结果 495株假丝酵母菌属占总分离病原菌(3027株)的比例为16.4％,其中白色假丝酵母菌397株,占80.2％;从呼吸道标本中分离出443株,占89.5％;白色假丝酵母菌对两性霉素B、5-氟胞嘧啶、氟康唑、伏立康唑、伊曲康唑的耐药率分别为0.3％ (1/397)、1.5％(6/397)、2.8％ (11/397)、4.8％( 19/397)、10.6％(42/397).结论 白色假丝酵母菌是真菌感染的主要病原菌,早期诊断和合理使用抗真菌药物是防治真菌感染的关键.     

白念珠菌耐药机制的研究进展

近年来白念珠菌感染发病率剧增,随着抗真菌药物的广泛使用,耐药菌株不断出现,耐药现象已经成为药物治疗的严峻挑战。目前已经明确的耐药机制包括：膜转运蛋白的过度表达,药物作用靶酶基因过度表达或突变,甾醇合成通路中其他酶的改变,生物被膜的形成,小囊状空泡的影响等。本文对白念珠菌的耐药机制做一综述。     

Reversal of fluconazole resistance induced by a synergistic effect with Acca sellowiana in Candida glabrata strains

Context: The increased incidence of non-albicans Candida (NAC) resistant to fluconazole (FLZ) makes it necessary to use new therapeutic alternatives. Acca sellowiana (O.berg) Burret (Myrtaceae) is a guava with several proven biological activities. The interaction with fluconazole can be a feasible alternative to overcome this resistance.

Objective: This study evaluates the in vitro antifungal activity of fractions obtained from the lyophilized aqueous extract of the leaves of A. sellowiana against resistant strains of NAC.

Materials and methods: The antifungal activity of the fractions was evaluated at 500?μg/mL by microdilution method. Checkerboard assay was performed to determine the effect of the combination of the F2 fraction and antifungal at concentrations: MIC/4, MIC/2, MIC, MIC?×?2 and MIC?×?4.

Results: Candida glabrata showed the lowest MIC values (500–3.90?μg/mL) and the F2 active fraction was the most effective. The association of F2 with FLZ showed a strong synergistic effect (FICI?≤?0.5) against 100% of C. glabrata resistant isolates. Moreover, the F2 active fraction has demonstrated that probably acts in the cell wall of these yeasts. There was no observed acute dermal toxicity of lyophilized aqueous extract of leaves of A. sellowiana on pig ear skin cells.

Discussion and conclusion: The interaction between substances present in the F2 active fraction is possibly responsible for the antifungal activity presented by this fraction. This study is unprecedented and suggests that the combination of F2 active fraction and FLZ might be used as an alternative treatment for mucocutaneus infections caused by C. glabrata resistant.     

没食子酸联合氟康唑抗耐药非白念珠菌作用的体外试验

目的：研究没食子酸与氟康唑联用对耐药光滑念珠菌和克柔念珠菌的体外抗真菌活性。方法：采用棋盘微量稀释法测定没食子酸与氟康唑单用及联用对耐药光滑念珠菌和克柔念珠菌的抗真菌作用,以部分抑菌浓度指数（FICI）评价其联用效果;并以CG2、CK8为目标菌株,采用时间-杀菌曲线进行验证;通过测定没食子酸对耐药株生物膜形成早期黏附性的影响,初步探讨药物联合抗真菌耐药的作用。结果：联用时8~16 μg·mL^-1没食子酸能将氟康唑的MIC值降为单用时的1/4~1/8,FICI值为0.375,呈现较好的协同作用,且量效关系呈正相关。时间-杀菌曲线表明,与氟康唑单用相比,没食子酸与氟康唑联用24 h时,CG2、CK8菌株CFU的lg值分别下降了2.1个单位和2.25个单位,均表现为协同作用。另外,研究发现没食子酸对生物膜形成的早期黏附有明显的抑制作用。结论：没食子酸与氟康唑联用对耐药光滑念珠菌和克柔念珠菌的浮游菌表现出体外协同抗真菌作用,且没食子酸能够明显抑制非白色念珠菌生物膜形成的早期黏附。     

真菌耐药的现状与对策

真菌耐药的报道日益增多，目前的研究一方面进一步探讨真菌产生耐药的机制、传播方式、耐药性与临床治疗的关系，以及建立标准化抗真菌药物敏感试验，从而控制耐药性的进一步发展；另一方面加快开发新的抗真菌药物，以应对日益增多的耐药真菌。     

120株肠球菌耐药分析及药物选择

目的观察肠球菌属的临床分布特点及耐药状况。方法收集医院2011年1月～6月培养检出的120株肠球菌属,分析其在各种临床标本中的分布特征和耐药状况。结果检出粪肠球菌63株(52.5%)、屎肠球菌48株(40.8%)、其他肠球菌8株(6.7%)。其中尿液中检出58株肠球菌(48.3%)。屎肠球菌的耐药率普遍较粪肠球菌高。未检出耐万古霉素的尿肠球菌和粪肠球菌,检出耐利奈唑胺粪肠球菌2株。结论肠球菌属感染以粪肠球菌和屎肠球菌为主,肠球菌属中各种菌对抗菌药物的耐药性有差异,应在抗菌药物敏感试验指导下并结合感染部位合理地选用抗菌药物。     

白色念珠菌生物被膜形成和由其产生的耐药机制

白色念珠菌以生物被膜方式生长是相对于其悬浮生长状态而言的另一种独特的生长形式,其最具特征的表型是对多种抗真菌药物表现出高度耐药.本文对近年来白色念珠菌生物被膜形成的分子机制及其产生的耐药机制的研究进展进行综述.     

临床分离的铜绿假单胞菌株耐药谱变迁的分析

目的 调查近4年来临床分离的铜绿假单胞菌对常用抗生素的耐药谱的变化。方法 菌株鉴定使用VITEK-32全自动微生物分析仪,药敏试验采用K-B纸片法,对我院近4年来铜绿假单胞菌的耐药谱进行回顾性调查。结果铜绿假单胞菌对青霉类G和头孢唑啉耐药率最高,达90％以上;耐药率上升速度快的是喹诺酮类药物和氨基糖甙类药物：耐药率最低的是亚胺培南。4年都维持在10％左右。结论铜绿假单胞菌的耐药性严重,亚胺培南的体外抗菌活性强,可用于治疗铜绿假单胞菌引起的感染。     

Nano-technology for targeted drug delivery to combat antibiotic resistance

Several microbes have evolved clinically significant resistance against almost every available antibiotic. Yet the development of new classes of antibiotics has lagged far behind our growing need. Frequent and suboptimal use of antibiotics particularly in developing countries aggravated the problem by increasing the rate of resistance. Therefore, developing new and multidimensional strategies to combat microbial infections is warranted. These include i) modification of existing antibiotics, ii) searching new and novel antibiotics, iii) development and improvement of antibiotics carrier system to reduce amount and frequency of antibiotic doses, iv) development of targeted antibiotic delivery systems. Here, the authors discuss trends and development of nano-materials and alternative antimicrobials to solve the problem of antibiotic resistance.     

成人尿标本临床分离菌的分布及耐药性监测

目的：研究成人尿标本临床分离菌的分布及其耐药性，为临床使用抗菌药物提供依据。方法：收集某院2016年1月-2018年12月尿培养阳性菌株，采用VITEK 2-Compact仪器法或纸片扩散法测定分离菌的药物敏感性，参照CLSI 2018版折点判读结果，用WHONET5.6软件统计分析。结果：共分离出2 164株病原菌，革兰阴性杆菌占72.13%，革兰阳性球菌占23.01%，真菌占4.85%；主要为大肠埃希菌（50.05%）和肠球菌（14.33%）。3年间大肠埃希菌对喹诺酮类、碳青霉烯类耐药率有下降趋势，对头孢类耐药率无明显变化；肠球菌对喹诺酮类耐药率较高且无明显变化趋势，对青霉素类、高浓度庆大霉素耐药率有较大下降。革兰阴性杆菌对亚胺培南、美洛培南、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦较敏感。屎肠球菌对所测试抗菌药耐药率显著高于其他肠球菌，未发现耐万古霉素、替考拉宁和利奈唑胺革兰阳性球菌。结论：尿路感染病原菌分布广泛，主要为肠杆菌科细菌和肠球菌。及时送检尿标本做病原学检查，根据药敏结果、严格按照抗菌药物临床应用分级管理办法使用抗菌药，可以减缓或降低细菌耐药性的产生。     

A novel polyamide SL-A92 as a potential fungal resistance blocker： synthesis and bioactivities in

Aim:

To synthesize a novel polyamide SL-A92 and evaluate its bioactivity against drug resistance in Candida albicans.

Methods:

SL-A92 was synthesized using N-hydroxybenzotriazole (HOBT)/N,N''-dicyclohexylcarbodiimide (DCC) in solution phase. Its antifungal activities and effects on strain growth were tested using the micro-broth dilution method and growth curves, respectively. Induced drug resistance in the C. albicans collection strain SC5314 was obtained by incubation with fluconazole (12 μg/mL) for 21 passages. Meanwhile, incubations with SL-A92 plus fluconazole were also carried out in SC5314 strains, and the MIC₈₀s were used to evaluate the inhibitory effects of SL-A92 on drug resistance during the induction process. Real time RT-PCR was performed to investigate the CDR1 and CDR2 mRNA levels in induced SC5314 strains.

Results:

SC5314 strain induced by the combination of fluconazole and SL-A92 (200 μg/mL) did not develop drug resistance. On day 24, the CDR1 and CDR2 mRNA levels in SC5314 strain co-treated with fluconazole and SL-A92 relative to fluconazole alone were 26% and 24%, respectively, and on day 30 the CDR1 and CDR2 mRNA levels were 43% and 31%, respectively.

Conclusion:

SL-A92 can block the development of drug resistance during the fluconazole induction process, which partially results from the down-regulation of CDR1 and CDR2.     

Inhibition of bacterial efflux pumps: a new strategy to combat increasing antimicrobial agent resistance

Resistance to multiple drugs in medically important bacteria results in therapeutic challenges for the clinician. The mechanisms by which bacteria evade the effects of antimicrobial agents are many, but in recent years it has become apparent that efflux is a significant means of resistance and probably explains the intrinsic resistance to numerous drugs observed in species such as Pseudomonas aeruginosa. Drug efflux is mediated by membrane-based hydrophobic proteins belonging to several distinct families, the members of which are related by structural characteristics, mechanism of action and energy source for the transport process. The multi-drug efflux transporters are particularly problematic as they are capable of extruding numerous structurally dissimilar drugs. Inhibition of these pumps, and even those with more limited substrate specificity, has been shown to decrease intrinsic resistance, reverse acquired resistance and reduce the emergence of mutants with higher-level target-based mutational resistance. Combining broad spectrum efflux pump inhibitors with current drugs that are pump substrates can recover clinically relevant activity of those compounds and thus may reduce the need for the discovery and development of new antimicrobial agents that are not pump substrates. Additional effort toward the identification, characterisation and determination of the clinical utility of efflux pump inhibitors is warranted.     

细菌生物膜形成与细菌耐药机制研究进展

细菌生物膜是一个具有结构性、协调性和功能性的高度组织群体,其相关感染因为对抗生素的耐药性成为临床难治性感染的重要原因之一。本文参阅近年来国内外研究结果,介绍了细菌生物膜的结构及特性,重点讨论其形成发展,抗生素耐药机制及防治策略方面的研究进展,对于寻找有效控制手段,指导临床合理用药和开发新药有重要意义。     

念珠菌感染特性与耐药性分析

目的：探讨本院念珠菌的感染特性及耐药性特点。方法随机抽取2000个标本,分离出615株念珠菌,采用科码嘉显色培养基培养,用念珠菌药敏测定试剂盒进行药敏试验。结果615株念珠菌里面,白色念珠菌含量最高,痰液检出率最高,呼吸科分布最多;65岁以下患者念珠菌的分离率明显低于65岁以上的患者。药敏实验中,5-氟胞嘧啶、两性霉素B、制霉菌素、酮康唑对常见念珠菌的敏感率均大于95%;益康唑对常见念珠菌敏感率大于80%;伊曲康唑、氟康唑、咪康唑对常见念珠菌的敏感率均小于50%。结论要重视菌株特性与耐药性,合理使用抗菌药物。     

体外诱导白念珠菌对氟康唑耐药性的研究

目的:建立白念珠菌耐氟康唑模型,研究白念珠菌耐药前后相关生物学特性变化。方法:体外用氟康唑诱导敏感白念珠菌SC5314和y01.09成为耐药子代SC5314R和y01.09R,利用微量液基稀释法和小鼠体内实验确定耐药表型,通过生长动力学、菌丝和生物膜形成实验观察生物学特性变化。结果:氟康唑对耐药子代SC5314R和y01.09R的MIC80分别为>128μg/mL,64μg/mL。无药培养35代后,MIC80分别为>128μg/mL,16μg/mL。有/无氟康唑环境下,敏感母本和耐药子代倍增时间无显著差异。氟康唑作用下,SC5314和y01.09菌丝形成受到抑制,SC5314R和y01.09R仍有菌丝形成;SC5314R和y01.09R可以形成牢固生物膜,SC5314和y01.09形成松散生物膜。结论:本实验成功诱导对氟康唑产生高度耐药的白念珠菌菌株,其耐药性通过体内外实验获得证实。     

耐两性霉素B的近平滑与热带假丝酵母菌的体外诱导及耐药分子机制研究

目的：体外诱导近平滑假丝酵母菌（ CP）、热带假丝酵母菌（ CT）对两性霉素B（ AMB）的耐药株,检测其中的耐药基因表达情况。方法 AMB体外构建耐药株,用实时荧光定量PCR法检测耐药基因的表达水平。结果 CP、CT 野生株经体外 AMB 浓度递增法诱导后,形成耐药株最低抑菌浓度（ MIC,≥8μg? mL－1）;CYP51A、CYP51B、CDR1、CDR2、MDR1及MDR2基因在野生株中低水平表达,在耐药株中表达水平明显升高,差别有统计学意义（ P ＜0．05）;CYP51A、CYP51B、CDR1、CDR2、MDR1及MDR2的表达量在CPAMB耐药株中分别是其野生株的136．92,16．33,2．07,14．84,4．07,2．38倍;在CT AMB耐药株中分别是其野生株的8．83,2．98,3．00,2．40,2．30,3．57倍。结论 CP、CT对AMB耐药与CYP51A、CYP51B、CDR1、CDR2、MDR1及MDR2基因过度表达有关。     

大肠埃希菌中Ⅰ类整合子耐药基因的分析

目的 对临床分离大肠埃希菌株携带的Ⅰ类整合子及相关耐药基因进行筛选和分析.探讨Ⅰ类整合子在大肠埃希菌耐药中的作用.方法 对43株大肠埃希菌临床分离株做药敏试验;采用PCR扩增、DNA测序、DNA序列比对的方法 对其携带的Ⅰ类整合子相关耐约基因进行分析.结果 43株大肠埃希菌分离株对10种抗菌药物的耐药率依次为亚胺培南4.7%、阿米卡星18.6%、头孢他啶、27.9%、头孢吡肟37.2%、头孢呋辛55.8%、复方磺胺甲嗯唑58.1%、妥布霉素74.4%、庆大霉素79.1%、头孢噻肟81.4%和哌拉两林83.7%.在43株大肠埃希菌分离株中有25株含有Ⅰ类整合子,其中18株携带整合子相关耐药基因,如介导对磺胺类和氨基糖苷类约物的耐药基因等;某些菌株携带的整合子相关耐药基因相同.结论 Ⅰ类整合子在大肠埃希菌中广泛存在,整合子相关耐约基因在该菌耐药性的形成和播散中发挥作用.     

念珠菌对两性霉素B耐药机制及其相应治疗策略的研究进展

念珠菌是临床上最常见的条件致病性真菌,其发病率呈逐年上升的趋势.两性霉素B是目前治疗深部真菌感染的有效药物,是抗真菌治疗的金标准.但近年来对两性霉素B耐药的念珠菌的出现给临床抗真菌感染带来挑战,因此,对念珠菌对两性霉素B耐药的机制以及相应治疗手段的研究十分必要.本文针对近年来念珠菌的流行趋势、两性霉素B作用机理、念珠菌对其耐药机制以及能够提高两性霉素B效果的治疗策略的研究进展进行总结阐述,为临床治疗念珠菌病新型技术和手段的研发奠定基础.     

Epidemiology of clinical isolates of Candida albicans and their susceptibility to triazoles

The study comprised strains of Candida albicans isolated from patients hospitalised in a tertiary care hospital during a 2-year period. In total 851 strains were cultured, including 379 (44.5%) strains from internal medicine patients, 243 (28.6%) from surgical patients and 229 (26.9%) from patients in the surgical intensive care unit. The strains were tested for susceptibility to the triazoles: fluconazole and itraconazole. There were 523 (61.5%) strains susceptible, 11 strains (1.3%) showed intermediate susceptibility and 317 (37.2%) were resistant to fluconazole, while 403 (47.3%) strains were susceptible, 43 (5.1%) intermediately susceptible and 405 (47.6%) resistant to itraconazole. Regular surveillance of fungal resistance patterns should be carried out and there should be prudent use of hospital triazole usage.