耐万古霉素肠球菌的耐药机制及耐药基因研究

目的:研究耐万古霉素的肠球菌的耐药机制和基因分型.方法:通过对2009年1月至2011年7月广州市胸科医院和中山大学附属第三医院的住院患者的痰、尿液及脓液分泌物中培养出268例肠球菌株,采用纸片扩散法对万古霉素等抗生素进行药敏分析,其中4株为耐万古霉素肠球菌,采用多重PCR检测肠球菌对万古霉素的耐药基因.结果:其中3株耐万古霉素肠球菌的基因表型均为vanA型,另外1株未测出.结论:耐万古霉素肠球菌的基因型与耐药情况有相关性.     

万古霉素耐药的屎肠球菌感染一例

肠球菌属于人体正常菌群,当抵抗力低下时可侵入机体,引起泌尿系感染、菌血症、腹腔感染及感染性心内膜等多部位感染,是临床常见的条件性致病菌.近年来,由于广谱抗菌药物广泛使用,肠球菌对抗菌药物的耐药现象日趋严重,多重耐药的肠球菌感染不断增加,给临床控制感染带来了很大困难.我们从一外伤患者分泌物中分离出一株万古霉素耐药的屎肠球菌,现报告如下.     

多重PCR检测万古霉素耐药的肠球菌

目的检测2005～2007年澳大利亚墨尔本地区万古霉素耐药的肠球菌基因。方法用多重PCR检测肠球菌4种耐药基因(vanA,vanB,vanC1和vanC2),鉴定4种肠球菌E.faecalis(粪肠球菌),E.faecium(屎肠球菌),E.gallinarum(母鸡肠球菌)和E.casseliflavus(产黄肠球菌)。结果vanA基因扩增阳性可见732bp条带;vanB基因为635bp条带;vanC1基因为822bp条带;vanC2/3基因为439bp条带。粪肠球菌基因扩增见941bpDNA条带,屎肠球菌为550bpDNA条带。3年回顾性研究中,最常见的万古霉素耐药基因是vanB型(84.9%),菌种是屎肠球菌(76.3%)。2007年还出现2株同时含有vanA和vanB耐药基因的屎肠球菌菌株。结论万古霉素耐药的肠球菌菌株逐年增多,多重PCR检测万古霉素耐药的肠球菌,简便迅速,有利于准确及时地发出报告。     

新型肠球菌万古霉素耐药基因簇——vanM基因簇

目的从屎肠球菌临床分离株中克隆一种介导屎肠球菌对万古霉素耐药的新基因簇。方法采用16SrRNA测序对临床株Efm-HS0661进行菌种确认,并行多位点序列分型（MLST）;通过药敏试验及接合试验,了解菌株耐药性及其可转移性;通过PCR扩增、步移法测序、限制性内切酶片段克隆获取万古霉素耐药基因及其周边序列,并将获得序列与已知万古霉素耐药基因簇进行比对。结果临床株经16SrRNA测序确认为屎肠球菌,MLST分型属ST78型;该菌株对万古霉素及替考拉宁耐药,且可通过接合试验发生转移;测序获得一6592bp核苷酸序列,为含6个万古霉素耐药相关基因的基因簇,其基因结构与已知耐药基因簇不同,命名为vanM型基因簇。其中vanM全长1032bp,其编码蛋白VanM与VanA、VanB、VanD、VanF基因氨基酸序列同源性分别为79．7％、69．7％、66．0％和78．5％。结论从万古霉素耐药屎肠球菌临床株中发现了一种新型万古霉素耐药基因簇——vanM型基因簇。     

万古霉素耐药肠球菌的表型及基因型检测

目的了解我院耐万古霉素肠球菌(VRE)的耐药表型、基因型及流行情况。方法用K-B纸片扩散法检测临床分离肠球菌的药物敏感性,E-test法检测VRE对万古霉素的最低抑菌浓度(MIC);PCR检测vanA、vanB、vanC1和vanC2-3基因型;脉冲场凝胶电泳(PFGE)分析VRE同源性。结果 73株肠球菌中检出3株万古霉素耐药屎肠球菌,检出率为4.1%;3株屎肠球菌对万古霉素和替考拉宁均耐药,但对利奈唑胺敏感;基因型检测显示3株屎肠球菌均为vanA型,PFGE结果显示该3株VRE不属于同一型别。结论我院住院患者中已出现VRE,应加强医院感染控制,以阻止VRE菌株在院内的传播和流行。     

万古霉素耐药肠球菌的药敏表型及基因特性研究

目的研究万古霉素耐药肠球菌(VRE)的耐药表型和基因特性。方法采用浓度梯度法(E-test)测定VRE对万古霉素(VA)、替考拉宁(TP)的耐药表型;采用聚合酶链反应检测vanA、vanB、vanC1、vanC2、vanC3基因,并对van基因产物进行测序。结果万古霉素耐药基因检测结果:VRE经PCR扩增,均获得vanA基因阳性片段。未检测到vanB、vanCl及vanC2/3基因。结论万古霉素耐药肠球菌的耐药表型与耐药基因型一致,菌株之间有较高的同源性。住院患者肠道中VRE携带率高,是医院感染的危险因素。     

肠球菌对万古霉素药敏实验方法的探讨

目的 :用 4种药敏试验方法比较肠球菌对万古霉素药敏结果的可靠性。方法 :采用Vitek 32型GPB TG药敏卡、肉汤稀释法、K B纸片扩散法和琼脂筛选法进行球肠菌对万古霉素的药敏实验。结果 :Vitek药敏卡和肉汤稀释法的药敏结果无显著差异 (P >0 .0 5 ) ,K B法药敏结果与上述两种方法比较 ,有非常显著的差异 (P <0 .0 1)。结论 :肠球菌对万古霉素的药敏检测方法最好采用仪器法或肉汤稀释法 ,K B纸片扩散法度及耐药结果不可靠 ,琼脂筛选法检测对万古霉素低水平耐药的肠球菌最灵敏     

万古霉素耐药肠球菌的检测和分子流行病学分析

目的为了解本院万古霉素耐药肠球菌（VRE）的流行情况，对VRE株进行实验室检测和分子流行病学检测分析。方法采用多重PCR及测序检测万古霉素耐药基因van，Etest法测定VRE株对万古霉素、替考拉宁的耐药表型；应用脉冲场凝胶电泳（PFGE）对11株VRE进行检测流行病学分析。结果检出1株VanA、4株VanB、5株vanC1，1株VanC2，对万古霉素、替考拉宁的药敏表型与基因型一致；11株VRE中2号vanB株与5号vanB株显示出相同片段，其他VRE株则分别有多于5个区带不同。结论实验室准确检测VRE对防止VRE感染和流行是非常重要的；PFGE电泳分析结果表明了本院11株VRE医院感染为散发。     

耐万古霉素屎肠球菌感染1例

<正>肠球菌广泛分布于自然界,是人类正常菌群的一部分,同时也是医院感染的重要病原菌。肠球菌主要引起泌尿道感染,也可导致盆腔、腹腔感染以及菌血症等。现今随着抗菌药物的广泛应用,肠球菌耐药现象日趋严重,尤其是携带耐万古霉素     

Enterococci with Acquired Vancomycin Resistance in Pigs and Chickens of Different Age Groups

Results for isolation of glycopeptide-resistant enterococci from fecal samples of pigs and chickens were found to differ strongly depending upon the type and age of animals and isolation technique (direct selective plate or broth enrichment). Isolations were frequent in broiler chickens and in sows but rare in layer chickens.     

In Vitro Activity of Ampicillin or Vancomycin Combined with Gentamicin or Streptomycin Against Enterococci

Minimum inhibitory and bactericidal concentrations of four antibiotics and their combinations were determined for 38 strains of enterococci by a microtitration tube dilution technique. The drugs were ampicillin, vancomycin, gentamicin, and streptomycin; the combinations were ampicillin-gentamicin, ampicillin-streptomycin, vancomycin-gentamicin, and vancomycin-streptomycin. At achievable serum concentrations, ampicillin alone killed 60% of strains, whereas combination with streptomycin increased this to 90% and with gentamicin to 100%. Vancomycin alone showed striking inhibitory activity, but very poor bactericidal activity at achievable concentrations. Combination with one of the aminoglycosides increased the bactericidal activity substantially. When combined with ampicillin, gentamicin was both more active and showed synergistic bactericidal activity significantly more often (P < 0.01) than streptomycin.     

258株肠球菌耐药性分析及耐万古霉素基因检测

目的研究肠球菌的耐药率及耐万古霉素肠球菌(VRE)的耐药表型和基因型。方法按照美国临床和实验室标准化研究所(CLSI)2009年推荐的微量稀释法进行临床分离肠球菌对各类药物的最小抑菌浓度(MIC)检测,VRE进一步用E-test药敏试验确认;PCR法检测VRE的耐药基因。结果 2010年7月至2011年11月沈阳军区总医院共检出粪肠球菌95株,屎肠球菌163株。粪肠球菌对万古霉素、替考拉宁保持较高敏感度,对氨苄西林、青霉素、呋喃妥因三种抗菌药物敏感度也在65%以上,对其他抗菌药物敏感度低,统计期内未检出耐万古霉素粪肠球菌菌株。屎肠球菌对多数抗菌药物表现为耐药,对氯霉素敏感率为70%,对万古霉素、替考拉宁敏感度下降,为90.7%。期间检出15株VRE,其耐药表型为多重耐药,PCR扩增结果显示,15株万古霉素耐药屎肠球菌VanA基因扩增均为阳性,产物长度在700～1000bp之间,约783bp,符合预期;VanB、VanC引物扩增均阴性。15株万古霉素耐药屎肠球菌对多数抗菌药物耐药,仅对氯霉素、四环素相对敏感,对万古霉素MIC>256mg/L,对替考拉宁也表现为耐药。结论屎肠球菌耐药性高于粪肠球菌,VRE多为多重耐药,给临床治疗带来困难,医院应加强对其预防监测。     

Transfer of Beta-Lactamase Genes of Neisseria gonorrhoeae by Conjugation

Recent isolates of Neisseria gonorrhoeae have been shown to be resistant to penicillin because they produce beta-lactamase. In this study, conjugal transfer of the beta-lactamase gene to a recipient N. gonorrhoeae strain occurred in one of the two strains studied but not in the other. The transconjugant could also conjugally transfer the beta-lactamase gene to an Escherichia coli strain.     

Synergy of Penicillin-Netilmicin Combinations Against Enterococci Including Strains Highly Resistant to Streptomycin or Kanamycin

The in vitro activity of combinations of penicillin and netilimicin was determined against 20 clinical isolates of enterococci and compared with that obtained in simultaneous tests with penicillin/sisomicin, penicillin/streptomycin, and penicillin/kanamycin. Synergy between the two drugs in each combination was determined by the use of quantitative kill curves and was defined as a killing by the combination at least 100-fold greater than that produced by the most effective drug alone. Penicillin/netilmicin and penicillin/sisomicin combinations were found to be synergistic against the majority of isolates tested, including strains resistant to penicillin/streptomycin or penicillin/kanamycin combinations. This synergy with penicillin could be demonstrated at a concentration of 相似文献   

Antibiotic activity against urinary tract infection (UTI) isolates of vancomycin-resistant enterococci (VRE): results from the 2002 North American Vancomycin Resistant Enterococci Susceptibility Study (NAVRESS)

BACKGROUND: The purpose of this study was to assess the prevalence of vancomycin-resistant enterococci (VRE) in urinary isolates in North America, and the activity of various antibiotics against VRE. MATERIALS AND METHODS: Twenty-eight medical centres in the United States and 10 centres in Canada assessed the prevalence of VRE in urinary isolates in 2002. Each study site was asked to collect up to a maximum of 50 consecutive VRE (Enterococcus faecium, Enterococcus faecalis only) urinary isolates. Susceptibility was determined by NCCLS broth microdilution. The prevalence of vanA and vanB resistance genotypes was determined by multiplex PCR. RESULTS: From the 28 US medical centres, a total of 697 VRE (616 [88.4%] E. faecium and 81 [11.6%] E. faecalis) were received. Approximately 75% of all VRE (E. faecium and E. faecalis) isolates demonstrated a VanA phenotype (resistance to both vancomycin and teicoplanin). PCR detection of vanA and vanB resistance determinants showed that the vanA genotype was present in 584 of 697 (83.8%) VRE isolates, whereas 113 (16.2%) isolates possessed the vanB gene. The most active agents were linezolid, nitrofurantoin and chloramphenicol, with 0.3%, 0.6% and 2.4% resistance, respectively. The majority (77.8%) of vancomycin-resistant E. faecium isolates displayed the VanA phenotype, and 538 of these 616 (87.3%) isolates were PCR-positive for vanA; the vanB genotype was detected in 78 (12.7%) isolates. Resistance was lowest with linezolid, chloramphenicol and nitrofurantoin at 0.3%, 0.3% and 0.5%, respectively. Only three genetically indistinguishable vanA-positive E. faecium were isolated from the 10 Canadian medical centres. CONCLUSION: VRE urinary isolates are common in the United States, are primarily of the vanA genotype and are very susceptible to linezolid, nitrofurantoin and chloramphenicol. In Canada, VRE urinary isolates remain uncommon.     

Vancomycin pharmacokinetics in patients with peritonitis on peritoneal dialysis

Vancomycin pharmacokinetics were studied in four patients with peritonitis undergoing chronic intermittent peritoneal dialysis. Serum levels exceeding 4.0 micrograms/ml were maintained for 8 and 13 days after a single 1-g intravenous dose. Vancomycin serum concentrations measured before, during, and upon completion of dialysis revealed no appreciable decline. Peritoneal fluid concentrations in two patients exceeded 4.0 micrograms/ml for more than 12 days.