浓度梯度法用于耐甲氧苯西林葡萄球菌的检测

尝试用浓度梯度法对耐甲氧苯西林葡萄球菌进行检测，并验证其精确性，连续性，稳定性。方法，应用Ｅｔｅｓｔ法苯唑西林和甲氧苯西林试条检测５８例临床分离葡萄球菌的耐药率，并对其中２９株菌采用Ｅｔｅｓｔ法和Ｍｉｃｒｏｓｃａｎ法对青霉素，苯唑西林，万古霉素等６种抗生素进行最低抑菌浓度结果的比较。     

Vitek—AMS,MicroScan与E test的药敏结果比较

比较Ｅ ｔｅｓｔ、ＶＩｔｅｋ－ＡＭＳ、Ｍｉｃｒｏ Ｓｃａｎ三种药敏试验的检测结果，方法：用三种方法对３０株Ｇ＾－杆菌菌株作了１９０次药敏平行试验。全部菌株均作Ｖｉｔｅｋ－ＡＭＳ、ＭｉｃｒｏＳｃａｎ自动鉴定并与ＡＰＩ作了对照。结果：以Ｅｔｅｓｔ药敏结果作为     

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）；并分别测定了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，耐甲氧西林金黄色葡萄球菌（ＭＲＳＡ）占４４．０％（３７／８４）（筛选法），耐甲氧西林凝固酶阴性葡萄球菌占６１．８％（１３４／２１７）（筛选法），ｍｅｃＡ基因ＰＣＲ法、琼脂筛选法检测ＭＲＳ阳性率较高；ＭＲＳ对青霉素等１３种抗生素的耐药率均高于ＭＳＳ；病人住院天数、抗生素使用与ＭＲＳ的分离率呈正相关。结论ＭＲＳ感染较为严重，需加强其对抗生素包括万古霉素的耐药性监测；注意ＭＲＳ检测方法存在的问题。     

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。     

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。     

2种超广谱β—内酰胺酶测定方法与确诊试验的比较

随着对质粒介导的超广谱 β 内酰胺酶 (ＥＳ ＢＬｓ)研究的深入 ,人们认识到检测ＥＳＢＬｓ的重要性 ,但这些产ＥＳＢＬｓ菌株往往不能用常规药物敏感试验来区别 ,以至于延误了临床治疗 ,或造成地区的流行。ＥＳＢＬｓ检测分筛选和确诊 2个层次。我们通过双纸片协同试验、Ｅ ｔｅｓｔ和纸片确诊试验对ＥＳＢＬｓ的测定作一探讨。材料和方法一、材料1 .菌株　从我院 1 998年临床标本中分离出的 1 2 5株大肠埃希菌和肺炎克雷白菌中用ＭｉｃｒｏＳｃａｎ筛选出 (头孢泊肟ＭＩＣ≥ 2 μｇ/ｍｌ)ＥＳＢＬｓ初筛阳性株 5 5株 ;大肠埃希菌ＡＴＣＣ …     

聚合酶链反应检测耐甲氧西林金黄色葡萄球菌mecA基因

建立聚合酶链反应（ｐｏｌｙｍｅｒａｓｅｃｈａｉｎｒｅａｃｔｉｏｎ，ＰＣＲ）检测耐甲氧西林金黄色葡萄球菌（ｍｅｔｈｉｃｉｌｌｉｎ－ｒｅｓｉｓｔａｎｔＳ．ａｕｒｅｕｓ，ＭＲＳＡ）ｍｅｃＡ基因的技术。四种ＤＮＡ提取方法检测灵敏度依次为超声裂解法（５×１０５ＣＦＵ／ｍｌ）、溶菌酶表面活性剂法（５×１０６ＣＦＵ／ｍｌ），表面活性剂法（１×１０７ＣＦＵ／ｍｌ）和直接煮沸法（１×１０８ＣＦＵ／ｍｌ），直接煮沸法具有简便性。引物的正链位于１８１～２００、负链位于３１１～３３０，序列分别为５＇－ＧＡＡＡＴＧＡＣＴＧＡＡＣＧＴＣＣＧＡＴ，５＇－ＧＣＧＡＴＣＡＡＴＧＴＴＡＣＣＧＴＡＧＴ，其扩增产物长度为１５０ｂｐ。五种常见菌证明本法具有较高特异性。苯唑青霉素ＭＩＣ水平与ｍｅｃＡ基因之间具有很好的相关性，ＭＩＣ≥４μｇ／ｍｌ的２２株菌均检出ｍｅｃＡ基因，提示苯唑青霉素常规检测ＭＲＳＡ的可行性。ＰＣＲ方法对于隐匿型耐药株的检出具有重要价值。     

5种方法鉴定耐甲氧西林葡萄球菌的实验比较

我们采用Ｅｔｅｓｔ和聚合酶链反应（ＰＣＲ）等５种方法对２００株葡萄球菌的甲氧西林特性进行研究，分析各方法的准确性，探讨建立鉴定耐甲氧西林葡萄球菌（ＭＲＳ）的有效途径，指导临床诊断与治疗。１材料与方法１．１菌株来源２００株葡萄球菌分离株由我所与广州市红...     

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     

In vitro activity of LY146032 against gram-positive bacteria

The activity of LY146032 (LY) was evaluated against 269 clinical isolates: 150 Staphylococcus spp. (Staph), 45 enterococci, 51 Clostridium spp., and 23 peptostreptococci. LY was compared to penicillin, metronidazole, imipenem, clindamycin, oxacillin, ciprofloxacin, vancomycin, and ampicillin. LY and oxacillin were tested against Staph by microdilution in cation-supplemented Mueller-Hinton broth (CSMHB), and in unsupplemented Mueller-Hinton broth (MHB). For LY, the MIC 90s in CSMHB were 16-32 dilutions lower. Among the Staph, the MIC 90s for LY, vancomycin, and ciprofloxacin were 4 micrograms/ml, 4 micrograms/ml, and 2 micrograms/ml respectively. The MIC 90s for enterococci by agar dilution were as follows: LY 8 micrograms/ml; ampicillin 4 micrograms/ml; imipenem 4 micrograms/ml; vancomycin 4 micrograms/ml; and ciprofloxacin 2 micrograms/ml. Clindamycin and penicillin were the most effective drugs against peptostreptococci and Clostridia spp., but LY was the most active drug against Clostridium difficile. The bactericidal activity of LY was determined by 24-hr time-kill curves in MHB. These showed a bactericidal effect against enterococci, and a bacteriostatic effect against three of four strains of Staph. Synergy was demonstrated against enterococci and Staph when LY was tested with aztreonam, ceftriaxone, or tobramycin. LY is a promising new agent against gram-positive bacteria, including methicillin resistant strains of staphylococci and enterococci.     

Susceptibility of a variety of clinical isolates to linezolid: a European inter-country comparison

Using standardized in vitro susceptibility tests, 3382 bacteria recently isolated from skin, blood or respiratory tract infections were analysed for their susceptibility to linezolid, a new oxazolidinone, and a number of comparator antibacterial agents. Isolates originated in France, Italy, Germany, Spain, Sweden, The Netherlands and the UK. Laboratories in each country independently conducted broth microdilution susceptibility tests using NCCLS methods and epsilonometry (Etest). Isolates of Gram-positive cocci tested in each laboratory included methicillin-susceptible and -resistant Staphylococcus aureus, methicillin-susceptible and -resistant Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae and Enterococcus spp. Isolates of Moraxella catarrhalis and Haemophilus influenzae were also included. Where appropriate, comparator drugs (oxacillin, vancomycin, gentamicin, co-amoxiclav, ciprofloxacin, erythromycin, penicillin G, clindamycin and ampicillin) were also tested. Linezolid demonstrated excellent activity against all of the Gram-positive cocci with MIC50s ranging from 0.5 to 4 mg/L. The drug demonstrated only modest activity against M. catarrhalis and H. influenzae with MIC50s ranging from 4 to 16 mg/L.     

In vitro susceptibilities of four species of coagulase-negative staphylococci.

The in vitro susceptibilities of 260 strains of coagulase-negative staphylococci to penicillin G, oxacillin, nafcillin, methicillin, cephalothin, and seven non-beta-lactam antimicrobial agents were determined and compared with the susceptibilities of 54 strains of Staphylococcus aureus with known patterns of susceptibility. Penicillin G susceptibility for S. aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus hominis was readily determined by using beta-lactamase tests with induced cells and with a standardized microdilution test. MIC criteria for susceptibility used for S. aureus were applicable to the coagulase-negative species. Percentages of organisms susceptible were as follows: S. epidermidis, 7%; S. haemolyticus, 5%; and S. hominis, 47%. Oxacillin susceptibility for these four species was readily determined by using a modification of the microdilution test. MIC criteria for susceptibility used for S. aureus were applicable to S. haemolyticus and S. hominis, but alternate criteria were necessary for S. epidermidis. Percentages of organisms susceptible were as follows: S. epidermidis, 29%; S. haemolyticus, 36%; and S. hominis, 97%. Staphylococcus saprophyticus differed from the other staphylococcal species; all strains were beta-lactamase negative and were penicillin susceptible but had higher penicillin G MICs than did susceptible strains of the other species. There was total cross resistance among the penicillinase-resistant penicillins and cephalothin for the coagulase-negative staphylococci as well as for S. aureus; oxacillin MICs were more reliable than MICs of the other drugs or a standardized disk diffusion test for distinguishing resistant from susceptible strains. Vancomycin, rifampin, and ciprofloxacin were consistently active against all staphylococci. Erythromycin, clindamycin, gentamicin, and trimethoprim-sulfamethoxazole were more active against oxacillin-susceptible staphylococci than against oxacillin-resistant staphylococci.     

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。     

Comparison of a polymerase chain reaction assay and a conventional microbiologic method for detection of methicillin-resistant Staphylococcus aureus.

The presence or absence of a methicillin resistance gene in 58 clinical isolates of Staphylococcus aureus was examined by the polymerase chain reaction (PCR) and Southern blot analyses. The results were analyzed in relation to those of the MIC assay of methicillin and oxacillin. PCR assay results were identical to those of Southern blot analysis of genomic DNA digested with HindIII (positive, 28 strains; negative, 30 strains). Among the 28 PCR-positive strains, 6 strains showed methicillin susceptibility by the conventional susceptibility test (MICs, less than or equal to 8 micrograms/ml). Culturing of the six strains with ceftizoxime led to an increase in the phenotypic level of resistance to methicillin and oxacillin, indicating that these strains should be classified as methicillin-resistant S. aureus (MRSA). The PCR assay was found to be a sensitive and reliable procedure for the rapid diagnosis of MRSA infection, even in cases in which the conventional MIC assay failed to detect MRSA.     

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.     

Activity and mechanism of action of DuP 105 and DuP 721, new oxazolidinone compounds

The in-vitro activities of DuP 721 and DuP 105, new oxazolidinone antibacterials, were compared with those of cefazolin, cephalexin, ciprofloxacin, clindamycin, oxacillin, penicillin, and vancomycin against Gram-positive cocci. DuP 721 was approximately four-fold more active than DuP 105 with an MIC of 2.0 mg/l for 90% of the Staphylococcus aureus, beta-haemolytic streptococcus and Streptococcus faecalis strains tested, and an MIC of 4.0 mg/l for 90% of the Str. faecium, penicillin-resistant Str. pneumoniae and viridans streptococcus strains tested. DuP 105 was most active against strains of Staph. epidermidis with an MIC of 4.0 mg/l for 90% of the strains tested. There was no cross resistance between these and the other antibacterial agents that were tested. Both oxazolidinones had bacteriostatic activity in broth against susceptible organisms. Both DuP 721 and DuP 105 inhibited ribosomal protein synthesis in a cell-free system. These synthetic, orally absorbable compounds represent a new series of antibacterial agents unrelated by chemical structure to any other currently available antimicrobial agents.     

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.     

Methicillin-Resistant Staphylococcus aureus Susceptibility Testing by an Automated System, Autobac I

The Autobac I system was used to evaluate the antibiotic susceptibility pattern of methicillin-resistant Staphylococcus aureus isolates. The results of the Autobac I were compared with the results of the disk diffusion method. The disk diffusion susceptibility pattern showed resistance to methicillin/oxacillin, penicillin, erythromycin, clindamycin, and kanamycin. All isolates were susceptible to cephalothin, chloramphenicol, tetracycline, and gentamicin. There was at least 96% agreement using the Autobac I system with all antibiotics except methicillin and clindamycin. Seventy percent of 57 isolates were recorded as susceptible to methicillin, whereas 9% had an intermediate susceptibility. With clindamycin, 14% were recorded as susceptible and 7% were recorded as intermediate. Upon prolonged incubation of the Autobac I cuvette, the agreement between the two methods was 44% for methicillin and 93% for clindamycin. Changes in the environmental conditions, such as use of 5% sodium chloride broth and a 32 degrees C incubation temperature, did not increase the detection of methicillin-resistant isolates by the Autobac I system.     

Evaluation of antibacterial sensitivity testing methods for methicillin-resistant Staphylococcus aureus in a dermatology outpatient population

Over a period of one year, 1986-1987, 116 strains of Staphylococcus aureus were isolated from patients attending two outpatient dermatology clinics in Houston, Texas. The purpose of this study was to evaluate the adequacy of routine antibiotic sensitivity testing methods for detecting methicillin-resistant Staphylococcus aureus (MRSA). The Kirby-Bauer disk diffusion method was compared with a commercially available screening medium containing 6 micrograms/ml of oxacillin and 4% NaCl. The minimal inhibitory concentration (MIC) of methicillin, oxacillin, and oxacillin with 4% NaCl to S aureus using the agar dilution method was also determined. Approximately 90% of S aureus strains produced beta-lactamase and were resistant to penicillin and ampicillin. By disk diffusion, no strains were resistant to methicillin, though diameters of zones of inhibition were between 10 and 14 mm in seven strains. All strains proved to be sensitive to methicillin by MIC determinations and on the oxacillin-NaCl screening medium. The MIC of methicillin was 2.5 micrograms/ml for the majority of strains of S aureus, between 0.16 and 0.31 microgram/ml for oxacillin, and 0.08 to 0.16 microgram for oxacillin with 4% NaCl. We concluded that the incidence of MRSA in an outpatient dermatology population is low, and a combination of disk diffusion and oxacillin-NaCl screening is adequate for testing sensitivity.