耐甲氧西林葡萄球菌耐药性观察

目的 研究葡萄球菌的感染及耐药性状况，指导临床用药。方法 ＡＰＩ－Ｓｔａｐｈ鉴定分离菌株，药敏试验应用Ｋ－Ｂ法、最低抑菌浓度（ＭＩＣ）法、琼脂筛选法及ｍｅｃＡ基因聚合酶链反应（ＰＣＲ）检测耐甲氧西林葡萄球菌（ＭＲＳ）；并分别了ＭＲＳ、甲氧西林敏感葡萄球菌（ＭＳＳ）对青霉素等１３种抗生素的耐药率（Ｋ－Ｂ法）；分析了病人住院时间、抗生素使用与ＭＲＳ分离率间的关系。结果 ３０１株葡萄球菌中，耐甲西林金黄     

耐甲氧西林葡萄球菌的临床检测

目的探讨沈阳地区耐甲氧西林葡萄球菌（ＭＲＳ）的感染情况、流行特征。方法应用ＭＲＳ鉴别培养，聚合酶链反应产物的酶联检测（ＥＤ－ＰＣＲ）及常规药敏试验法。结果从７６株葡萄球菌中检出耐甲氧西林金黄色葡萄球菌（ＭＲＳＡ）１０株，耐甲氧西林血浆凝固酶阴性葡萄球菌（ＭＲ－ＣＮＳ）１３株。１０株ＭＲＳＡ的血泺凝固酶型别主要集中在Ⅵ型，Ⅱ型次之。结论沈阳地区耐甲氧西林葡萄球菌感染较为严重（２３／７６），主要的血浆凝固酶型别为Ⅲ型。３种检测方法比较，ＥＤ－ＰＣＲ法具有操作简便、特异、敏感等优点，宜于推广应用     

耐甲氧西林葡萄球菌四种检测方法的比较及临床应用

用ｍｅｃＡ基因检测法、琼脂筛选法、Ｅ试验和Ｋ－Ｂ纸片扩散法检测１００株临床分离的葡萄球菌甲氧西林耐药株（ＭＲＳ）,比较其阳性检出率,对其可靠性和临床实用性进行评估,结果：凡ｍｅｃＡ阳性葡萄球菌（６９／１００）其琼脂筛选法均为阳性,其中６７株苯唑西林ＭＩＣ大于４μｇ／ｍｌ,２株凝固酶阴性葡萄球菌（ＣＮＳ）为２μｇ／ｍｌ。在琼脂筛选法显示耐药的菌株（７３／１００）中,４株为ｍｅｃＡ阴性,且均检出β－内     

耐甲氧西林葡萄球菌的临床检测

目的探讨沈阳地区耐甲氧西林葡萄球菌（ＭＲＳ）的感染情况，流行特征，应用ＭＲＳ鉴别培养，聚合酶链反应产和的酶联检测（ＥＤ－ＰＣＲ）及常规药敏试验法。结果从７５株葡萄球菌中同耐甲氧西林金黄色葡萄球菌（ＭＲＳＡ）１０株，耐甲氧西林血浆凝固酶阴性力葡萄球菌（ＭＲＣＮＳ）１３株。１０株ＭＲＳＡ的血浆凝固酶型别主要集中在Ⅳ型，Ⅱ型次之，结论 沈阳地区耐甲氧西林葡萄球菌染较为严重（２３／７６），主要的血浆凝固酶     

耐甲氧西林金黄色葡萄球菌体外抗菌活性研究

为给临床合理选用抗生素和有效控制耐甲氧西林金黄色葡萄球菌（ＭＲＳＡ）的感染提供依据，对ＭＲＳＡ的耐药特点进行了研究。测定了１７种抗生素对临床分离的７５株金黄色葡萄球菌的最低抑菌浓度和β－内酰胺酶。结果表明，临床分离菌的６６．７％为ＭＲＳＡ，ＭＲＳＡ中产β－内酰胺酶菌株占９２％。所有ＭＲＳＡ对青霉素Ｇ、氨苄青霉素和洁霉素耐药，但皆对万古霉素敏感，对丁胺卡那霉素、氟哌酸、氟嗪酸、环丙氟哌酸、头孢哌酮等敏感率大于５５％。ＭＲＳＡ耐抗生素种类数为５到１６种不等。对苯唑青霉素耐药水平越高，则耐抗生素种类数也越多，二者呈显著正相关（ｒ＝０．９３５３，Ｐ＜０．００５）。建议治疗ＭＲＳＡ感染首选万古霉素。     

耐甲氧西林金黄色葡萄球菌体外抗菌活性研究

为给临床合理选用抗生素和有效控制耐甲氧西林金黄色葡萄球菌（ＭＲＳＡ）的感染提供依据，对ＭＲＳＡ的耐药特点进行了研究，测定了１７种抗生素的对临床分离的７５株金黄色葡萄球菌的最低抑菌浓度和β－内酰胺酶。结果表明，临床分离菌的６６．７％为ＭＲＳＡ，ＭＲＳＡ中产β－内酰胺酶菌株占９２％，所有ＭＲＳＡ对青霉素Ｇ，氨苄青霉素和洁霉素耐药，但皆对万古霉素敏感，对丁胺卡那霉素，氟哌酸，氟嗪酸，环丙氟哌酸，头孢哌酮     

金黄色葡萄球菌耐药性分析

目的了解金黄色葡萄球菌（ＳＡ）尤其是耐甲氧西林金黄色葡萄球菌（ＭＲＳＡ）的耐药状况，指导临床合理用药。方法对本院感染标本中分离出的２２３株ＳＡ分别进行了药敏试验和β－内酰胺酶测试，并以“ＷＨＯＮＥＴ３”软件对试验数据进行分析处理。结果ＭＲＳＡ占ＳＡ感染标本总数的５８．３％，ＭＲＳＡ及甲氧西林敏感金黄色葡萄球菌（ＭＳＳＡ）产β－内酰胺酶的百分率无明显差异。ＭＲＳＡ与ＭＳＳＡ皆对万古霉素敏感。此外，ＭＲＳＡ对１８种抗生素中的１５种呈现多重耐药，耐药率介于２８％～１００％。而多数ＭＳＳＡ仅对西林Ｇ和氨苄西林耐药。结论万古霉素是治疗ＭＲＳＡ感染的首选抗生素。ＭＲＳＡ的耐药性应引起广泛关注。     

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。     

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一个辅助基因和细菌中均为有１６ＳｒＲＮＡ基在引物,通过多重ＰＣＲ技术对标本进行放增。结果 １２３株金黄色葡萄球菌的     

32例耐甲氧西林金黄色葡萄球菌败血症临床分析

３２例耐甲氧西林金黄色葡萄球菌败血症临床分析王振营耐甲氧西林金黄色葡萄球菌（简称ＭＲＳＡ）是医院内感染的重要病原之一，致病性与对甲氧西林敏感的金黄色葡萄球菌（简称ＭＳＳＡ）相似。国内开展ＭＲＳＡ及其感染的研究尚少。为引起临床重视，现将我院１９９１～１...     

Methicillin-resistant Staphylococcus aureus susceptibility testing with Abbott MS-2 system.

The antimicrobial susceptibilities of 100 methicillin=resistant Staphylococcus aureus strains were concurrently determined by the Abbott MS-2 System and by the standard disk diffusion method. Agreement between the two methods was 94% or greater for all of the antibiotics tested except for methicillin and gentamicin. This study indicates that the Abbott MS-2 cannot be relied upon for detection of methicillin resistance in clinical S. aureus isolates.     

In vitro activities of 28 antimicrobial agents against Staphylococcus aureus isolates from tertiary-care hospitals in Korea: a nationwide survey

Staphylococcus aureus, one of the most frequently isolated pathogens in both hospitals and the community, has been particularly efficient at developing resistance to antimicrobial agents. As methicillin-resistant S. aureus (MRSA) has prevailed and, furthermore, as S. aureus with reduced susceptibility to vancomycin has emerged, the therapeutic options for the treatment of S. aureus infections have become limited. To update the current status of antibiotic resistance, clinical S. aureus isolates were collected from eight university-affiliated hospitals from June 1999 to January 2001. Susceptibility tests with 28 antibiotics were performed by the disk diffusion method. Among a total of 682 isolates, the methicillin resistance rate was 64% (439 of 682), and most of the MRSA isolates were resistant to multiple classes of antibiotics. Although a constitutive macrolide-lincosamide-streptogramin B resistance phenotype was common, no isolates were resistant to quinupristin-dalfopristin or linezolid. Rifampin, fusidic acid, trimethoprim-sulfamethoxazole, and arbekacin showed superior in vitro activity compared with the other antibiotics against the MRSA isolates. No isolates showed reduced susceptibility to vancomycin.     

Detection of Methicillin Resistance in Coagulase-Negative Staphylococci Initially Reported as Methicillin Susceptible Using Automated Methods

Reliable detection of methicillin resistance in coagulase-negative staphylococci (CNS) is required for appropriate therapy of serious infections from these pathogens. To determine the most accurate method of measuring methicillin resistance in CNS initially reported as methicillin susceptible by automated methods, we compared mecA detection by polymerase chain reaction (PCR) with phenotypic methods. One hundred eighty-eight blood culture isolates of CNS that were initially reported as susceptible to methicillin using commercial methods (Vitek or MicroScan) were tested by agar dilution, disk diffusion, oxacillin salt agar screen plate, and a multiplex PCR assay using primer sets for mecA and 16S rRNA. Sixteen isolates (8.5%) previously reported as methicillin susceptible by automated methods contained the mecA gene. MICs of these isolates ranged from 0.5 μg/mL to ≥128 μg/mL. Ten of these isolates had MICs equal to or below the NCCLS breakpoint of 2 μg/mL. Six of the 10 isolates (4 with MICs of 0.5 μg/mL and 2 with MICs of 2 μg/mL) did not grow on any of the oxacillin screen plates after 48 h of incubation at 30°C or 35°C. All six isolates were induced to grow in the presence of oxacillin at 128 μg/mL by serial passaging on plates containing increasing concentrations of antibiotic. Retesting with MicroScan and Vitek detected methicillin resistance in 7 and 10 isolates, respectively. Disk diffusion testing with incubation for 48 h proved to be the next best method after PCR for detection of methicillin resistance (15 of 16 isolates). Commercial automated methods and some methods recommended by National Committee for Clinical Laboratory Standards may not detect methicillin resistance in CNS that carry the mecA gene and have MICs just below breakpoint.     

Detection and expression of methicillin/oxacillin resistance in multidrug-resistant and non-multidrug-resistant Staphylococcus aureus in Central Sydney,Australia

Ninety clinical Staphylococcus aureus isolates from separate patients were examined phenotypically and genotypically for susceptibility to methicillin/oxacillin. Thirty were methicillin/oxacillin susceptible and 60 were methicillin and oxacillin resistant (MRSA). The 60 MRSA isolates examined were subdivided into two groups according to their antibiotic profiles and comprised 30 non-multidrug-resistant (NMDR) isolates, resistant to less than two non-beta-lactam antibiotics, and 30 multidrug-resistant (MDR) isolates, resistant to three or more non-beta-lactam antibiotics. Phenotypic and genotypic analysis of methicillin/oxacillin showed that despite use of the guidelines published by the NCCLS for the testing of S. aureus susceptibility to methicillin/oxacillin, MIC values of some NMDR MRSA isolates fell below the NCCLS-recommended breakpoints. Etest strips failed to detect two NMDR MRSA isolates tested with oxacillin and four tested with methicillin. Lowering the NCCLS-recommended oxacillin screen agar concentration from 6 to 2 mg/L and temperature of incubation to 30 degrees C, improved the specificity and sensitivity of NMDR MRSA detection from 87% to 100%. On PFGE analysis these NMDR MRSA strains were genotypically different. Genotypic tests, such as multiplex PCR for the mecA/nuc genes and DNA hybridization for the mecA gene, or phenotypic monoclonal antibody-based tests to detect penicillin-binding protein 2a (PBP2a) offer advantages for problematic isolates in detecting or confirming low-level phenotypic heterogeneous mecA expression of oxacillin and methicillin resistance in NMDR MRSA.     

Rapid MRSA detection by a latex kit.

Methicillin resistant strains of Staphylococcus aureus (MRSA) are implicated in serious infections and nosocomial outbreaks, and show resistance to a wide range of antibiotics, thus limiting the treatment options. Therefore, rapid detection is clinically crucial for both treatment and infection control measures. This study assessed the performance of a rapid latex agglutination kit marketed to detect MRSA clinical isolates (MRSA-Screen test Denka Seiken Co Ltd, Tokyo, Japan) based on detecting a specific penicillin binding protein 2a (PBP2a) in comparison to the NCCLS oxacillin salt agar screen plate, the 1 microg oxacillin disk diffusion test, and the oxacillin MIC by E-test. Testing was carried out on 133 isolates consisting of 99 MRSA and 34 methicillin sensitive strains of S. aureus (MSSA). Concordant results were observed between the latex kit and all the other tests for the 99 MRSA isolates. Only 1 of the 34 MSSA isolates gave a positive agglutination reaction in the latex kit. The kit sensitivity and specificity were determined to be 100% and 97%, respectively. This reliable performance indicates that the MRSA-Screen latex test is very useful test for the rapid detection of MRSA isolates in the clinical microbiology laboratory.     

住院儿童耐甲氧西林葡萄球菌耐药性分析

目的了解住院儿童耐甲氧西林葡萄球菌(MRS)的耐药现状,为临床治疗和控制该类感染提供依据。方法细菌鉴定采用APIStaph和TH-168鉴定编码管,药敏试验采用头孢西丁纸片扩散法。结果 2007～2009年住院儿童各种标本MSR的检出率为23.7%,其中痰液检出率最高(43.9%),耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)检出率为27.8%,明显高于耐甲氧西林金黄色葡萄球菌(MRSA)(9.9%)。MSR对庆大霉素、红霉素、克林霉素、复方新诺明耐药严重,对阿米卡星、利福平较为敏感,尚未发现耐万古霉素的菌株。结论 MRS的耐药性不断增强,已经成为儿童感染的重要病原菌,临床上应根据药敏结果合理选用抗菌药物,并采取有效措施防止耐药菌在医院内传播。     

Phenotypic detection of mec A-positive staphylococcal blood stream isolates: High accuracy of simple disk diffusion tests

Detection of oxacillin-resistance in staphylococci by phenotypic methods remains problematic. Although standardized susceptibility test methods are adequate for Staphylococcus aureus, many are less satisfactory for the coagulase-negative staphylococci (CNS). We have studied 108 consecutive blood culture isolates of staphylococci. The mec A gene was detected by PCR in one S. aureus and 55 CNS isolates. Susceptibility testing was performed as follows: oxacillin (1-μg), ceftizoxime (30-μg), and cephalothin (30-μg) by disk diffusion; oxacillin, ceftizoxime, cephalothin, methicillin, ampicillin, ampicillin/sulbactam, penicillin, cefazolin, imipenem, and meropenem by the broth microdilution method. In addition, isolates were tested by the oxacillin agar screen plate method. The single oxacillin-resistant S. aureus strain was detected by all oxacillin susceptibility test methods and by the ceftizoxime disk and MIC methods. Two oxacillin-susceptible S. aureus were intermediate (minor error) by ceftizoxime broth microdilution (MIC, 16 μg/mL). The most sensitive, simple phenotypic methods for detection of oxacillin-resistant CNS (mec A positive) were as follows: oxacillin disk diffusion at 98%, oxacillin screen plate at 91%, oxacillin broth microdilution at 87%, ceftizoxime disk diffusion at 100%, ceftizoxime broth microdilution at 87%, and methicillin broth microdilution at 83%. These results indicate that oxacillin and ceftizoxime disk diffusion tests are the most accurate phenotypic methods in routine clinical use for detection of oxacillin-resistant CNS. Oxacillin broth microdilution MIC testing (2% NaCl supplement) would perform more satisfactorily (100% sensitivity) with an adjusted interpretive breakpoint at ⩽0.5 μg/mL, in contrast to the lower accuracy of the “so-called” reference agar screen test.     

葡萄球菌感染的临床分布和耐药性监测及治疗对策

目的 研究葡萄球菌的临床分布和耐药性,指导临床合理应用抗生素。方法 应用ATB自动细菌鉴定仪及药敏分析仪对临床标本中分离的327株葡萄球菌进行鉴定和药敏试验,同时进行MRS检测,并结合临床资料进行分析。结果共分离出葡萄球菌327株,其中金葡菌138株(42.2％),居第一位;表皮葡萄球菌101株(30.9％)位居第二;其它如溶血葡萄球菌、人葡萄球菌、沃氏葡萄球菌等均占有一定比例。327株葡萄球菌中共检出耐苯唑西林葡萄球菌(MRS)230株,占70.3％,苯唑西林敏感葡萄球菌(MSS)97株。MSS对青霉素和红霉素的耐药率高,分别为80_8％-82.2％和44.4％-51.9％,对其它抗菌素均敏感。MRS对万古霉素、替考拉宁、呋喃妥因和利福平等敏感性高,对其余多种抗菌素耐药。葡萄球菌主要分离自呼吸道、泌尿道、感染伤口和血液等标本。科室分布依次是ICU、肿瘤科和外科等。结论 临床分离菌中的葡萄球菌日益增多,对抗菌素的耐药率增高,本院MRS检出率较高,应重视MRS的检测和药敏试验。同时,临床医师应根据药敏结果,合理有效地选用抗菌素。     

Determination of methicillin-resistance in Staphylococcus aureus by agar dilution and disc diffusion methods

Four-hundred and seventy-six isolates of Staphylococcus aureus from patients in Hong Kong were tested for methicillin-resistance by agar dilution and disc diffusion methods, using heavy inocula. With Mueller-Hinton agar incubated at 30 degrees C for 24 h, 216 (MRSA) isolates were resistant to 8 mg/l of methicillin and grew up to the edge of a 10 micrograms methicillin disc, and 260 strains were susceptible to greater than or equal to 4 mg/l methicillin and produced inhibition zones of at least 20 mm diameter. Incubation for 48 h, the addition of sodium chloride, or the use of a 5 micrograms disc had little effect on these results, but a significant number of MRSA strains produced inhibition zones when disc diffusion tests were incubated at 35 degrees C, and many sensitive strains showed scanty growth on salt-containing agar at high methicillin concentrations in agar dilution tests. Iso-Sensitest agar did not appear to support the growth of the minority resistant populations of MRSA unless supplemented with menadione and thiamine, and even with supplemented Iso-Sensitest medium a few presumptively resistant strains appeared methicillin-sensitive in both disc diffusion and agar dilution tests.     

纸片法头孢西丁敏感的青霉素耐药葡萄球菌分析

目的 评估不同检测方法 对纸片法头孢西丁敏感,苯唑西林耐药葡萄球菌耐药性状的检测能力,并对非mecA基因介导苯唑西林耐药的匍萄球菌进行药敏谱分析.方法 收集2007年1月至2009年5月间复旦大学附属华山医院就诊患者呼吸道、尿、分泌物和无菌体液标本中分离得到的255株金黄色葡萄球菌,采用苯唑西林纸片法、苯唑西林MIC法、头孢西丁纸片法、头孢西丁MIC法枪测金黄色葡萄球菌对苯唑西林的敏感性:用苯唑西林MIC法和头孢西丁纸片法检测75株凝固酶阴性萄萄球菌对苯唑西林的敏感性:将所有葡萄球菌进行mecA基因检测,结合试验结果 分析葡萄球菌苯唑西林耐药原因,并对非mecA基因介导的苯唑西林耐药葡萄球菌用MIC法进行抗菌药敏谱分析.结果 255株纸片法头孢西丁敏感、青霉素耐药的金黄色葡萄球菌苯唑西林纸片法检测出6株中介,4株耐药;头孢西丁纸片法、头孢西丁MIC法、苯唑西林MIC法全敏感、mecA基因检测全阴性.75株纸片法头孢西丁敏感、青霉素耐药的凝固酶阴性葡萄球菌,苯唑西林MIC法59株敏感,16株耐药;mecA基因阴性为71株,阳性为4株.12株非mecA基因介导苯唑西林耐药的葡萄球菌庆大霉素敏感为10株,克林霉素8株、环丙沙星11株、红霉素6株、甲氧苄啶/磺胺甲噁唑11株,头孢菌素类、替考拉宁、万古霉素、哌拉西林/他唑巴坦、四环素12株.结论 金黄色葡萄球菌用头孢西丁检测mecA基因介导的苯唑西林耐药,具有很好的可靠性.凝固酶阴性葡萄球菌最好同时使用头孢西丁纸片法和苯唑西林MIC法检测mecA基因介导的苯唑西林耐药,以提高检出率.非mecA基因介导的苯唑西林耐药,临床可依据实际药物敏感实验结果 选择性使用β内酰胺酶稳定的青霉素、β内酰胺酶抑制剂复合药、头孢类和碳青霉烯类药物治疗.