凝固酶阴性葡萄球菌的分布特点及耐药性分析

目的研究凝固酶阴性葡萄球菌（ＣＮＳ）的临床分布特点及耐药性。方法用经典生理生化鉴定方法，对各种临床标本分离到的１５０株ＣＮＳ进行种的鉴定及药敏试验。结果分离到１０种ＣＮＳ，其中表皮葡萄球菌占４２．８％，溶血葡萄球菌占３８．７％。青霉素耐药率为８６．２％。甲氧苯青霉素耐药葡萄球菌占５４．６％（８２／１５０）。没有发现万古霉素耐药菌。结论临床各类标本ＣＮＳ中表皮葡萄球菌、溶血葡萄球菌占绝大多数，常规选用精氨酸、尿素、蕈糖、甘露糖、甘露醇等试验可将临床常见ＣＮＳ鉴别出来，治疗ＣＮＳ感染，首选万古霉素为宜。     

微量法检测念珠菌对三唑类药物敏感性与交叉耐药性

目的应用美国临床实验室标准化委员会（ＮＣＣＬＳ）推荐微量法测定酵母菌最低抑菌浓度（ＭＩＣ），并检验其重复性和准确性，观察氟康唑耐药株对伊曲康唑是否存在交叉耐药性。方法参照ＮＣＣＬＳ推荐的药敏试验方案微量稀释法（１９９５年版），检测２５株氟康唑耐药性白念珠菌及４８株临床分离株对氟康唑及伊曲康唑的敏感性。结果２５株氟康唑耐药白念珠菌中只有３株菌对伊曲康唑耐药（ＭＩＣ值≥４μｇ／ｍｌ），占１３．０４％，只有少数菌对伊曲康唑存在交叉耐药。４８株临床分离白念珠菌对氟康唑和伊曲康唑的ＭＩＣ值呈正态分布，有４６株对伊曲康唑的ＭＩＣ值介于０．００７５～４μｇ／ｍｌ，其半数抑菌浓度（ＩＣ５０）为０．１２５μｇ／ｍｌ，有４３株对氟康唑的ＭＩＣ值介于０．２５～１６μｇ／ｍｌ，其ＩＣ５０为２μｇ／ｍｌ。结论ＮＣＣＬＳ微量稀释法有较好的可重复性和稳定性，少数氟康唑耐药株对伊曲康唑有交叉耐药性。     

凝固酶阴性葡萄球菌苯唑西林筛选试验药物浓度的探讨

目的 选择一合适的筛选法检测凝固酶阴性葡萄球菌（ＣＮＳ）和苯唑西林（ＯＸＡ）浓度。方法 通过Ｋ－Ｂ纸片法、琼脂稀释法和β－内酰胺酶抑制试验对１４１株ＣＮＳ进行检测。结果 选择ＯＸＡ０．２５μｇ／ｍｌ时，有８株ＯＸＡ敏感株（ＭＳＳ）被误判为耐药株（ＭＲＳ），误判率为８．３３％；选择ＯＸＡ０．５μｇ／ｍｌ时，１株ＭＳＳ误判为ＭＲＳ，误判率为１．０４％；选择ＯＸＡ０．７５μｇ／ｍｌ时无ＭＳＳ或ＭＲＳ的误     

多重聚合酶链反应检测耐甲氧西林葡萄球菌

目的应用一种敏感快速的多重聚合酶链反应（ＰＣＲ）,检测耐甲氧西林的金黄色葡萄球菌（ＭＲＳＡ）和凝固酶阴性葡萄球菌（ＭＲＣＮＳ）。方法临床分离的北京地区金黄色葡萄球菌１２３株,ＭＲＣＮＳ１２２株,用溶壁素和蛋白酶Ｋ制备模板ＤＮＡ,设计葡萄球菌甲氧西林耐药的决定基因,金黄色葡萄球菌独有的一个辅助基因和细菌中均有的１６ＳｒＲＮＡ基因引物,通过多重ＰＣＲ技术对标本进行扩增。结果１２３株金黄色葡萄球菌的ｆｅｍＡ基因１００％（１２３／１２３）阳性,ｍｅｃＡ基因阳性的占１８．７％（２３／１２３）,１２２株ＭＲＣＮＳ的ｆｅｍＡ１００％（１２２／１２２）阴性,ｍｅｃＡ阳性的占２４．６％（３０／１２２）。１６ＳｒＲＮＡ基因片断在多重ＰＣＲ中作为内部参照避免了假阴性结果的出现。结论建立的多重ＰＣＲ技术检测ＭＲＳＡ和ＭＲＣＮＳ具有敏感、快速、特异的特点,是一种可靠的实验诊断手段。     

大肠埃希菌中检出多种质粒介导的AmpC酶

目的了解安徽省产质粒介导的AmpC β内酰胺酶细菌的基因型特征及耐药性。方法收集临床分离无重复大肠埃希菌共407株，采用头孢西丁三维试验检测AmpC酶，琼脂稀释法检测耐药性，PCR扩增各组基因及测序以确定AmpC酶基因型。结果头孢西丁三维试验阳性率为8．1％（33／407），其中质粒介导的AmpC β内酰胺酶的检出率为3．0％（12／407）。PCR扩增和测序结果证实为5株blaCMY-2、4株blaDHA-1和2株blaACT-2基因，并发现1株新的CMY型基因，DNA测序表明该基因和CMY-2有97％的同源性，并在国内首次发现blaACT-2他基因。药敏试验显示对头霉素和哌拉西林耐药，对亚胺培南100％敏感，2株产DHA-1型酶的菌株对头孢吡肟耐药。结论安徽省各地区已有质粒介导AmpC酶的出现，基因型有CMY-2、DHA-1和ACT-2。碳青霉烯类药物可作为治疗产质粒介导的AmpC酶细菌感染的首选药物。     

凝固酶阴性葡萄球菌的分布特点及耐药性分析

研究凝固酶阴性葡萄球菌的临床分布特点及耐药性。用经典生理生化鉴定方法，对各种临床标本分离到的１５０株ＣＮＳ进行种的鉴定及药敏试验。分离到１０种ＣＮＳ，其中表皮葡萄球菌点４２．８％，溶血葡萄球菌点３８．７％，青霉素耐药率为８６．２％。甲氧苯青霉素耐药葡萄球菌占５４．６％。没有发现万古霉素耐药菌。     

纹带棒状杆菌耐药性及院内传播特征分析

目的 揭示纹带棒状杆菌临床分离株耐药性及分子分型特征，为制定纹带棒状杆菌感染防治措施提供依据。 方法 收 集从临床标本中分离的 １２４ 株纹带棒状杆菌，经基质辅助激光解吸电离飞行时间质谱（ＭＡＬＤＩ?ＴＯＦ ＭＳ）和 １６Ｓ ｒＲＮＡ 鉴定后， 采用微量肉汤稀释法进行体外药敏试验，并分析交叉耐药情况；采用脉冲场凝胶电泳进行分子分型，并进行聚类分析。 结果 所有菌株均对环丙沙星耐药，９６．０％的菌株为多重耐药菌株。 １２４ 株纹带棒状杆菌可分为 ２８ 个耐药谱，其中，美罗培南－克 林霉素－四环素－头孢噻肟－环丙沙星－红霉素－青霉素为主要的耐药表型（３７．９％，４７ ／ １２４）。 克林霉素与红霉素、头孢噻肟与 青霉素、美罗培南与青霉素之间存在交叉耐药。 １２４ 株纹带棒状杆菌共分为 ４４ 个型别，其中优势型别为 ＣＳＳ０１． ＣＮ００５８、 ＣＳＳ０１．ＣＮ００２２、ＣＳＳ０１．ＣＮ００５５、ＣＳＳ０１．ＣＮ００１５，具有相同或相似的耐药谱。 结论 纹带棒状杆菌已逐渐发展为院内感染常见 病原菌，在院内传播过程中具有 ４ 个优势型别，耐药严重，传播能力强，应加强纹带棒状杆菌的系统监测。     

金黄色葡萄球菌的临床分布及耐药性分析

目的研究金黄色葡萄球菌尤其是耐甲氧西林金黄色葡萄球菌（MRSA）临床分布及耐药性分析,为有效控制感染提供科学依据。方法采用回顾性分析方法,对2007年6月至2009年3月检测的177株金黄色葡萄球菌的标本来源,科室分布及耐药性进行分析。结果177株金黄色葡萄球菌中MRSA135株占76．3％（135／177）,甲氧西林敏感金黄色葡萄球菌（MSSA）42株占23．7％（42／177）。标本来源以痰液最多106株,占59．9％（106／177）,其次为引流分泌物29株,占16．4％（29／177）,尿液为9．0％（16／177）;科室分布以重症监护室（Icu）、神经外科、呼吸科居多,分别占41．8％（74／177）、27．7％（49／177）、11．9（21／177）;MRSA科室分离率为ICU83．8％（62／74）,神经外科81．6％（40／49）,呼吸科66．7％（14／21）,普外科57．9％（11／19）。从耐药性来看,MRSA对β-内酰胺类、大环内酯类、喹诺酮类、氨基苷类等多种抗茵药物的耐药率均超过了80．0％,氯霉素、复方磺胺显示了较低的耐药率,利奈唑胺、奎奴普丁／达福普丁、万古霉素的耐药率均为0;MSSA对红霉素、头孢唑啉、氨苄西林、青霉素等的耐药率均在70％以上。结论金黄色葡萄球菌感染部位以呼吸道为主,其次为脓肿、泌尿系统感染;ICU、神经外科、呼吸科为感染的主要科室;MRSA分离率已达很高水平,MRSA的耐药性高于MSSA,应严格隔离、消毒,加强监测工作,合理选择抗菌药物。     

大肠埃希菌临床分离株对喹诺酮类抗菌药的质粒介导耐药

目的 了解近年来发现的质粒介导耐药机制在大肠埃希菌临床株对喹诺酮类耐药中所起的作用。方法 78株环丙沙星耐药菌株分离自上海5所教学医院。以克隆斑点杂交及Southern杂交方法筛选质粒介导耐药基因qnr；以接合试验了解喹诺酮耐药的可转移性；对qnr基因进行序列分析，以引物步移法对qnr周边质粒DNA进行测序、分析。结果 78株大肠埃希菌中，6株（7．7％）qnr检测阳性。在6株阳性菌中，喹诺酮耐药性均可通过质粒转移，接合子对环丙沙星的MIC较受体菌上升16～250倍。qnr基因与最早报道的序列一致，qnr位于In4族的Ⅰ类整合子上，本研究中的2个新整合子命名为In36及In37。结论 与qnr相关的质粒介导喹诺酮类耐药性在大肠埃希菌临床分离株中有一定程度流行，这可能是我国细菌对喹诺酮类耐药性上升迅速的原因之一。     

成人耐大环内酯类抗生素肺炎链球菌的实验研究

目的了解近年我国成人患者中分离的肺炎链球菌的耐药现状,为社区获得性呼吸道感染的抗菌药物选用提供依据。方法对临床明确诊断为社区获得性肺炎（CAP）及慢性气管炎急性加重（AECB）患者中分离获得肺炎链球菌;采用微量稀释法测定15种常用抗菌药物对肺炎链球菌的体外药敏结果;进行克林霉素诱导耐药性D试验;PCR扩增方法检测耐药基因。结果71株肺炎链球菌中,青霉素敏感肺炎链球菌（PSSP）70株（70／71）,占98．6％,青霉素中介肺炎链球菌（PISP）1株（1／70）,占1．4％。大环内酯类抗生素耐药肺炎链球菌（MRSP）60株（60／71）,占84．5％,MRSP中以cMLSn型耐药的菌株为主,有54株,占90％,其次为iMLS B型,占8．3％（5／60）,1株为M型,占1．7％（1／60）。60株MRSP中ermB基因阳性检出率最高,占98．3％（59／60）。结论我国成人引起社区获得性呼吸道感染的肺炎链球菌对大环内酯类抗生素的耐药率高,大环内酯类抗生素在CAP治疗中可依据体外药敏试验结果选用,并需与β内酰胺类抗生素联合应用。     

Routine use of the Gen-Probe MTD2 amplification test for detection of Mycobacterium tuberculosis in clinical specimens in a large public health mycobacteriology laboratory

The antimicrobial susceptibility of 239 coagulase-negative staphylococci (CNS) isolates consecutively collected from blood culture in patients admitted in a 600-bed teaching hospital was evaluated. The isolates were identified to the species level by conventional methods and the MicroScan Positive Combo Panel type 6 system, and their susceptibility to vancomycin, teicoplanin, and oxacillin were tested by agar dilution, disk diffusion, and MicroScan-WalkAway system. The species distribution was as follows: Staphylococcus epidermidis 120 (50.2%), S. hominis 29 (12.1%), S. haemolyticus 24 (10.0%), S. cohnii 14 (5.9%), and isolates from other CNS species 52 (21.8%). The percentage of resistance to oxacillin was 74.5% by agar dilution. The highest percentages of oxacillin resistance were found among S. haemolyticus (95.8%) and S. epidermidis (80.8%). Teicoplanin resistance (MIC > or = 32 micrograms/mL) was detected in five S. haemolyticus isolates, whereas intermediate resistance (MIC = 16 micrograms/mL) was detected in nine strains. These isolates with reduced susceptibility to teicoplanin were resistant to oxacillin, but remained susceptible to vancomycin (MIC < or = 4 micrograms/mL). Two isolates, one S. haemolyticus and one S. epidermidis, showed a vancomycin MIC of 8 micrograms/mL, and both MicroScan and disk diffusion methods classified these isolates as susceptible. Our results showed that glycopeptide resistance is emerging among CNS isolates in our institution and the disk diffusion method may not detect isolates with decreased susceptibility to these antimicrobial agents.     

Correlations between consumption of antibiotics and methicillin resistance in coagulase negative staphylococci

The correlation between antibiotic consumption, expressed in defined daily doses (DDD), and antibiotic resistance rates was studied, using 976 isolates of coagulase negative staphylococci (CNS) from human pathological material. Data from four hospitals, including 14 participating departments, were analysed for this purpose. Susceptibility tests were performed according to Dutch national standards, except for methicillin, which for the majority of isolates was tested according to adapted NCCLS standards. Resistance to methicillin was most frequent in Staphylococcus epidermidis (29%) and S. haemolyticus (16%). Among the departments, thoracic surgery (29-47%), surgical intensive care (68%) and neonatology (32%) scored highest. Significant correlations were found between percentages of methicillin resistance in CNS and consumption (DDD/month/bed) of (flu)cloxacillin (P0.008), of cephalosporins (P0.01) and of gentamicin (P0.005). (Flu)cloxacillin was used mainly prophylactically, cephalosporins and gentamicin therapeutically. Results were similar for S. epidermidis (n = 639) alone. There was no significant correlation between consumption and resistance to trimethoprim, erythromycin (P0.08) or gentamicin (P0.09). Analysis of data from individual patients showed significant differences in proportions of methicillin resistance rates in CNS, between use and non-use of penicillinase resistant beta-lactams or gentamicin. It is concluded that clinical use of both (flu)cloxacillin and cephalosporins selects for methicillin resistant CNS.     

凝固酶阴性葡萄球菌生物膜形成与多重耐药关系的研究

目的探讨临床怀本中凝固酶阴性葡萄球菌（coagulasenegativeStaphylococci,CNS）生物膜形成的状况,及其对细菌耐药的影响和多重耐药的关系,提高临床对CNS感染的重视,并帮助临床根据药敏试验结果选用抗菌药物。方法采用微孔板法制备生物膜,结晶紫染色,酶标仪比色检测42株CNS的生物膜形成情况;对临床标本分离的CNS进行鉴定,并采崩纸片法进行药敏试验;所有数据采用SPSS17．0统计软件进行统计学分析。结果比色法检测CNS的生物膜阳性率为76．19％（32／42）。药敏试验结果显示生物膜阳性的CNS耐药情况较严重,尤其是对青霉素G和红霉素,耐药率分别为96．88％和78．13％,对复办新诺明、克林霉素、四环素、环丙沙星耐药率亦超过50．00％,且呈多重耐药;生物膜阴性的CNS耐药情况较轻,仅对青霉素G和红霉素耐药情况较严重,耐药率分别为60．00％和140．00％;尚未发现对万古霉素耐药的CNS菌株。生物膜阳性CNS菌株对青霉素G、红霉素、克林霉索和复方新诺明的耐药率均显著高于生物膜阴性CNS菌株,差异均有统计学意义（P均〈0．05）。CNS生物膜生成多少与多重耐药的严重情况呈正相关性（r=0．975,P〈0．01）。结论临床标本分离出的CNS绝大部分能产生生物膜,对常见抗菌药物的耐约情况严重,且生物膜形成多少与多重耐药情况呈正相关关系。     

新生儿血培养病原菌分布及耐药性分析

目的了解大连市新生儿血培养病原菌分布及其对抗菌药物的耐药情况。方法对2014年8月至2015年8月住院的新生儿进行常规血培养、鉴定、药敏试验,对数据进行分析。结果 1 570例新生儿血培养标本中共检测出病原菌186株,阳性率为11.8%。其中革兰阳性菌占74.2%(138/186),并以表皮葡萄球菌为主。革兰阴性菌占25.3%(47/186),以洋葱伯克霍尔德菌为主。真菌1株,占0.5%。药敏结果显示革兰阳性菌对青霉素、红霉素耐药率较高(80.0%~90.0%),对万古霉素、利奈唑胺、替考拉宁100.0%敏感;大肠埃希菌和肺炎克雷伯菌对氨苄西林耐药率最高(88.2%~100.0%),对亚胺培南、阿米卡星100.0%敏感;对哌拉西林/他唑巴坦、头孢哌酮/舒巴坦、阿莫西林/克拉维酸、头孢吡肟、头孢他啶耐药率均较低(0~10.0%)。洋葱伯克霍尔德菌对替卡西林/克拉维酸和美罗培南耐药率高于80.0%,对头孢哌酮/舒巴坦、左氧氟沙星、米诺环素和复方磺胺甲噁唑100.0%敏感。结论大连市新生儿血培养病原菌以革兰阳性菌为主,凝固酶阴性葡萄球菌是主要病原菌,由于地区环境不同,病原菌及耐药情况应做定期监测分析,为临床合理使用抗菌药物提供客观、准确的依据。     

天津地区儿童血培养病原菌分布及耐药性研究

[目的]探讨天津地区儿童血培养的病原菌分布特点及其耐药情况,为临床诊疗提供参考。[方法]血培养采用BD9120全自动血培养仪,并以VITEK32全自动鉴定系统进行细菌的鉴定及药敏分析。[结果]血培养阳性率为6．3％,共分离出410株病原菌。其中革兰阳性菌268株占65．4％;革兰氏阴性菌137株占33．4％;真菌5株占1．2％。分离前五位的是凝固酶阴性葡萄球菌160株占39％、大肠埃希菌50株占12．2％、金黄色葡萄球菌39株占9．5％、肺炎链球菌33株占8．0％及肠球菌属31株占7．3％。CNS对青霉素、红霉素、氨苄西林／舒巴坦耐药率超过80％,但对万古霉素、呋喃妥因、利奈唑烷、莫西沙星敏感,MRCNS检出率为90．3％,MRSA检出率为50％;革兰氏阴性杆菌对氨苄西林、氨苄西林／舒巴坦、复方新诺明耐药率为50％～100％,但对亚胺培南、左旋氧氟沙星、哌拉西林／他唑巴坦、丁胺卡那较敏感。[结论]发现凝固酶阴性葡萄球菌是天津地区儿童血流感染的主要病原菌,了解病原菌分布特点及其耐药情况对临床合理选用抗菌药物具有重要意义。     

Molecular epidemiology of trimethoprim resistance among coagulase-negative staphylococci.

A 42% (70 of 167 isolates) incidence of resistance to 20 micrograms of trimethoprim per ml was found among clinical isolates of coagulase-negative staphylococci from two hospitals. A specific trimethoprim resistance gene probe from a conjugative Staphylococcus aereus plasmid was used to investigate the location of the trimethoprim resistance gene among 29 isolates. In 14 trimethoprim-resistant isolates, the probe hybridized with only chromosomal DNA, in 9 it hybridized with only plasmid DNA, and in 1 isolate both plasmid and chromosomal sequences showed hybridization. In five isolates there was no hybridization of the probe with either chromosomal or plasmid DNA. Four of these five nonhybridizing isolates were Staphylococcus haemolyticus. In contrast, all 22 Staphylococcus epidermidis isolates tested hybridized with the probe. The presence of the trimethoprim resistance gene in a chromosomal location was correlated with a lower MIC (median, 80 micrograms/ml) than when it was plasmid encoded (median, 1,250 micrograms/ml). Restriction endonuclease mapping as well as DNA hybridization of cloned plasmid and chromosomal DNA showed that there were 2.7 kilobases of common DNA in the two loci. This included the 500 base pairs of DNA mediating trimethoprim resistance and a total of 2.2 kilobases of 3'- and 5'-flanking sequences. The presence of the same gene and flanking sequences in chromosomal and plasmid locations suggests that the trimethoprim resistance determinant is translocated among different genetic loci.     

葡萄球菌对高水平莫匹罗星及奎奴普丁/达福普汀的耐药性

目的 了解临床分离的葡萄球菌对高水平莫匹罗星和奎奴普丁/达福普汀两种药物的耐药.方法 2009～2011年临床分离的669株葡萄球菌用K-B法检测其对两种药物的耐药性.结果 669株葡萄球菌共检出22株高水平莫匹罗星耐药株(MuH),总耐药率为3.29%,其中金黄色葡萄球菌(SA)3株,耐药率1.89%,凝固酶阴性葡萄球菌(CNS)19株,耐药率为3.73%;奎奴普丁/达福普汀耐药株52株,耐药率为7.77%,其中SA 7株,耐药率为4.40%,CNS45株,耐药率为7.77%.对两种药物的耐药率SA比CNS都稍低.结论 莫匹罗星和奎奴普丁/达福普汀对葡萄球菌具有强抗菌活性,都是治疗葡萄球菌感染的良好选择,且对SA的效果更优于CNS.     

RSF1010 and a conjugative plasmid contain sulII, one of two known genes for plasmid-borne sulfonamide resistance dihydropteroate synthase.

The nucleotide sequence of the type II sulfonamide resistance dihydropteroate synthase (sulII) gene was determined. The molecular weight determined by maxicells was 30,000, and the predicted molecular weight for the polypeptide was 28,469. Comparison with the sulI gene encoded by Tn21 showed 57% DNA similarity. The sulII-encoded polypeptide has 138 of 271 amino acids in common with the polypeptide encoded by sulI. The sulII gene is located on various IncQ (broad-host-range) plasmids and other small nonconjugative resistance plasmids. Detailed restriction maps were constructed to compare the different plasmids in which sulII is found. The large conjugative plasmid pGS05 and the IncQ plasmid RSF1010 contained identical nucleotide sequences for the sulII gene. This type of sulfonamide resistance is very frequently found among gram-negative bacteria because of its efficient spread to various plasmids.     

R plasmid with carbadox resistance from Escherichia coli of porcine origin.

Escherichia coli isolates of porcine fecal origin from a farm where the antibacterial agent carbadox was used were examined for resistance to carbadox (Cdxr). Of 72 strains examined, 24 showed resistance to this drug. All 24 Cdxr strains, except one, were also resistant to tetracycline (Tcr), streptomycin (Smr), spectinomycin (Spcr), sulfadimethoxine (Sur), kanamycin (Kmr), ampicillin (Apcr), or a combination of tetracycline, streptomycin, spectinomycin, sulfadimethoxine, and ampicillin. The Cdxr character was invariably transmissible by conjugation to E. coli K-12 jointly with other drug resistance, with the resistance patterns present in transconjugants being Cdxr Smr Spcr Apcr or Cdxr Smr Spcr Sur Apcr. About 25% of these transconjugants simultaneously lost the resistance to carbadox, streptomycin, spectinomycin, and ampicillin or carbadox, streptomycin, spectinomycin, sulfadimethoxine, and ampicillin or carbadox, streptomycin, spectinomycin, sulfadimethoxine, and ampicillin in the presence of acriflavine. Agarose gel electrophoretic analysis of deoxyribonucleic acid from a transconjugant showed a single plasmid deoxyribonucleic acid molecule with a molecular weight of about 28 x 10(6), which was capable of transforming E. coli C to Cdxr Smr Spcr Apcr. This resistance was transmissible by conjugation as a unit to other K-12 strains. These results confirmed the presence of an R plasmid specifying the Cdxr character in the host strain.