耐甲氧西林金黄色葡萄球菌及其肠毒素的检测和耐药性分析

目的评价乳胶结合试验检测耐甲氧西林金黄色葡萄球菌(MRSA)及其肠毒素(SE),并进行耐药性分析.方法收集130株金黄色葡萄球菌临床分离株,通过药敏试验将其分为耐甲氧西林金黄色葡萄球菌和甲氧西林敏感金黄色葡萄球菌(MSSA),用反向间接血凝试验(RPHA)检测金黄色葡萄球菌肠毒素.结果67株MR-SA产肠毒素,19株MSSA产肠毒素,MRSA产肠毒素率为100%,MSSA产肠毒素率为30%.结论实验室应重视金黄色葡萄球菌肠毒素的检测.     

2008-2010年舟山某院金黄色葡萄球菌的分布及耐药性变迁

目的 分析舟山医院三年来金黄色葡萄球菌分布及耐药性变迁,并对耐甲氧西林金黄色葡萄球菌(MRSA)与甲氧西林敏感金黄色葡萄球菌(MSSA)的耐药性差异做对比.方法 用ATB Expression半自动微生物分析仪进行菌株鉴定及药敏试验,用K-B法测红霉素、克林霉素、头孢西丁、苯唑西林直径,比较耐甲氧西林金黄色葡萄球菌(MRSA)与甲氧西林敏感金黄色葡萄球菌(MSSA)的耐药性差异.结果 金黄色葡萄球菌对苯唑西林、庆大霉素、红霉素、四环素和克林霉素的耐药率有上升的趋势;MRSA对苯唑西林、庆大霉素、复方新诺明、克林霉素、红霉素、青霉素、喹奴普汀-达福普汀、利福平和四环素的耐药率都明显高于MSSA的耐药率,二者间差异有统计学意义(P＜0.01),D-试验阳性71株,占72.45％.结论 金黄色葡萄球菌的耐药性逐渐升高,特别是对MRSA应引起临床的重视,检测克林霉素诱导型耐药具有重要的临床应用价值.     

男性泌尿生殖道感染标本葡萄球菌分离及抗菌谱分析

目的了解男性尿生殖道感染患者尿道分泌物和前列腺液葡萄球菌的分离及时抗菌药物的敏感情况.方法用法国生物梅里埃VITEK32型细菌鉴定分析鉴定分离自尿道分泌物和前列腺液的葡萄球菌及药敏试验,计算6种葡萄球以及耐甲氧西林(MRS)和甲氧西林敏感葡萄球菌(MSS)的分离率及构成比,以x2检验统计分析其差异.结果尿道分泌物葡萄球菌分离率(7.17%)明显低于前列腺液(22.16%)(P＜0.005).二者无论以溶血性葡萄球菌的分离率和构成比最高,其次为表皮葡萄球菌、金黄色葡萄球菌等4种葡萄球菌分离率及构成比较低,其分离情况也存在差异.2种标本各型MRS都有很高的阳性率,各种葡萄球菌对万古霉素100%敏感,MRS对多种抗菌药敏感率明显低于MSS(P＜0.005);各型MRS除万古霉素、呋喃妥因、利福平和林可霉素,对其余药物敏感率(S I)%较低;与总MRS比较,对利福平、复方新诺明、庆大霉素和呋喃妥因中1种或3种药物的敏感率(S I)%,耐甲氧西林的金黄色葡萄球菌、溶血葡萄球菌、模仿葡萄球菌或赛氏葡萄球菌差异有显著性(P＜0.025);其余差异无显著性(P＞0.05).结论凝固酶阴性的MRS为泌尿生殖道感染的重要病原菌,对多种抗菌药物敏感性显著降低且不同种存在差异,应重视各种MRS的分离和药敏试验,有助于指导临床合理用药,达到满意的疗效.     

公共场所物体表面葡萄球菌分布及耐药性调查

目的了解城市公共场所物体表面葡萄球菌的分布及耐药特征。方法培养法分离公共场所物体表面葡萄球菌,质谱法鉴定所属种,K-B法检测对抗菌药物的敏感性。结果从14个公共场所分离葡萄球菌219株,其中184株经鉴定分别属于金黄色葡萄球菌(14株,7.6%)和13种凝固酶阴性葡萄球菌(CoNS,170株,92.4%),最常见CoNS有表皮葡萄球菌(63株)、腐生葡萄球菌(29株)、人葡萄球菌(19株)、溶血葡萄球菌(16株)。分离的葡萄球菌对青霉素和红霉素的耐药率最高,分别为77.7%(143/184)和64.7%(119/184);仅20株(20/184,10.9%)对受试抗生素全部敏感。14株金黄色葡萄球菌均为甲氧西林敏感菌(MSSA),40.0%(68/170)CoNS为耐甲氧西林菌株(MRCoNS),60.0%(102/170)CoNS为甲氧西林敏感株(MSCoNS),未见对丁胺卡那、万古霉素和利奈唑胺耐药菌株。结论城市公共场所物体表面葡萄球菌存在种的多样性,以CoNS为主,耐甲氧西林葡萄球菌比例较高,耐药现象普遍。     

医院感染葡萄球菌的耐药性及D-试验研究分析

目的了解医院感染葡萄球菌的耐药性及克林霉素诱导试验（D-试验）临床意义。方法从住院患者标本中分离到的539株葡萄球菌进行药敏试验和D-试验,所得结果进行统计分析。结果葡萄球菌中耐甲氧西林金黄色葡萄球菌（MRSA）和耐甲氧西林凝固酶阴性葡萄球菌（MPSE）的检出率高,分别为65．1％和83．6％,各种葡萄球菌对万古霉素敏感率为100％,对阿奠西林头孢菌素在内的各种β-内酰胺酶类抗生素敏感率低于35％,对红霉素耐克林霉素敏感的D-试验阳性率为57．O％。结论葡萄球菌耐甲氧西林检出率,呈多重耐药,在选用大环内酯类,克林霉素类抗生素时要注意D试验,合理用药,提高疗效。     

六种微藻的抗MRSA活性筛选

本文以琼脂扩散法为体外抗菌活性测定方法,研究了六种微藻(两种绿藻,三种硅藻和一种蓝藻)的不同溶剂提取物对耐甲氧西林金黄色葡萄球菌的抑制活性.结果表明,每种微藻的提取物对耐甲氧西林金黄色葡萄球菌具有不同程度的抑制活性.其中,蓝隐藻、牟氏角毛藻和青岛大扁藻的提取物具有良好的抗菌活性.结论:微藻是一种新的开发抗耐甲氧西林金黄色葡萄球菌物质的潜在资源.     

葡萄球菌耐药性的监测分析

目的：研究葡萄球菌的感染及耐药性状况,指导临床合理用药。方法：常规方法及阳光微生物鉴定仪鉴定菌株。药敏试验用革兰阳性需氧球菌药敏检测卡,检测耐甲氧西林金黄色葡萄球菌（MRSA）和耐甲氧西林凝固酶阴性葡萄球菌（MRCNS）,金黄色葡萄球菌（SA）和凝固酶阴性葡萄球菌（CNS）对12种抗生素的耐药率。结果：158株葡萄球菌中,MRSA占47.5%（78/158）,MRCNS占21.5%(34/158),SA占70.9%（112/158）,CNS占29.1%(46/158)。耐甲氧西林葡萄球菌（MRS）对12种抗生素的耐药率均高于甲氧西林敏感葡萄球菌（MSSA）。结论：MRSA的耐药性较高,需加强其抗生素的耐药性检测。     

血培养中病原菌分布及药敏调查分析

目的了解血培养中病原菌的分布及药敏情况,供临床借鉴。方法对中山大学附属第三医院血培养标本中所分离到的细菌及药敏结果进行统计分析。结果从血培养标本中分离到细菌239株,其中其中革兰阴性杆菌(G-b)131株,占52.6%,革兰阳性球菌(G+c)99株,占39.8%(99/236),真菌占6.8%,大肠埃希菌和肺炎克雷伯菌产ESBLs菌检出率分别是54.2%和48.6%,只对亚胺培南、特治星和阿米卡星敏感,敏感率超过85%,G+c中,耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)的检出率分别是42.9%和89.2%,只对万古霉素敏感(100%),检出的肠球菌已出现对万古霉素耐药。结论血培养分离的病原菌分布复杂,产ESBLs菌和MRS菌株检出率高,临床应重视血培养检测结果.合理用药。     

葡萄球菌下呼吸道感染的细菌学分类及抗生素敏感性分析

目的：探讨葡萄球菌下呼吸道感染的细菌学分类情况及抗生素耐药性特点。方法：利用复星公司FOUTUNE IMS细菌鉴定药敏分析系统,凝固酶试验用试管法。结果：47株菌株分离到6种葡萄球菌,排在前3位的是施氏葡萄球菌、金黄色葡萄球菌、木糖葡萄球菌,其中金黄色葡萄球菌占29．8％。耐甲氧西林葡萄球菌（MRS）占78．7％,耐甲氧西林凝固酶阴性葡萄球菌（MRCNS）占凝固酶阴性葡萄球菌（CNS）78．8％;MRS对万古霉素敏感率为81．1％。MRS建议用药依次为万古霉素、呋喃妥因、氯霉素、四环素和喹诺酮类,未发现对万古霉素耐药的耐甲氧西林金黄色葡萄球菌（MRSA）。结论：凝固酶阴性、耐甲氧西林葡萄球菌成为下呼吸道球菌感染的主要菌株,MRS比例上升,MRS治疗首选万古霉素。     

耐甲氧西林葡萄球菌和肠球菌blaTEM及tetM基因检测

目的了解临床分离的耐甲氧西林葡萄球菌(MRS)和肠球菌中blaTEM及tetM基因存在状况。方法分离50株耐甲氧西林金黄色葡萄球菌(MRSA),7株耐甲氧西林表皮葡萄球菌(MRSE)、5株耐甲氧西林溶血葡萄球菌(MRSH)、15株粪肠球菌和9株屎肠球菌,采用PCR技术检测耐药基因。结果MRSA、MRSE、MRSH、粪肠球菌和屎肠球菌中blaTEM基因阳性率分别为40.0%、57.1%、60.0%、6.7%和88.9%,tetM基因阳性率分别为100%、0%、0%、66.7%、0%。结论blaTEM基因阳性率在MRS中较高,在屎肠球菌中则很高;携带tetM基因是MRSA和粪肠球菌对四环素耐药的主要原因。     

Extracellular superoxide dismutase

The extracellular space is protected from oxidant stress by the antioxidant enzyme extracellular superoxide dismutase (EC-SOD), which is highly expressed in selected tissues including blood vessels, heart, lungs, kidney and placenta. EC-SOD contains a unique heparin-binding domain at its carboxy-terminus that establishes localization to the extracellular matrix where the enzyme scavenges superoxide anion. The EC-SOD heparin-binding domain can be removed by proteolytic cleavage, releasing active enzyme into the extracellular fluid. In addition to protecting against extracellular oxidative damage, EC-SOD, by scavenging superoxide, preserves nitric oxide bioactivity and facilitates hypoxia-induced gene expression. Loss of EC-SOD activity contributes to the pathogenesis of a number of diseases involving tissues with high levels of constitutive extracellular superoxide dismutase expression. A thorough understanding of the biological role of EC-SOD will be invaluable for developing novel therapies to prevent stress by extracellular oxidants.     

Porcine superoxide dismutase

Summary A cuprozinc superoxide dismutase has been isolated from pig liver. The enzyme is similar to previously described cuprozinc superoxide dismutases in that it is a dimer of about 32 000 molecular weight consisting of approximately two equally sized subunits, and 2 atoms of copper and two atoms of zinc per molecule. It differs, however, from previously described cuprozinc superoxide dismutases because of its higher isoelectric point; pI 6.8 vs 4.9 for bovine enzyme. The diffusion coefficient for the porcine enzyme was determined to be 7.53×10⁻⁷ cm²s⁻¹, while the equivalent spherical hydrodynamic radius was computed as 28.5 ?. The enzyme was observed to undergo self-association with time. Sulfhydryl interaction is postulated to be involved.     

Reversal of the superoxide dismutase reaction

The superoxide dismutase from bovine erythrocytes has been shown to catalyze the reduction of oxygen by H₂O₂. This reversal of the spontaneous disproportionation of superoxide radicals was made feasible through the use of tetranitromethane as an effective scavenger for the superoxide radicals.     

Phenotypes of mice lacking extracellular superoxide dismutase and copper- and zinc-containing superoxide dismutase

Mice lacking the secreted extracellular superoxide dismutase (EC-SOD) or the cytosolic copper- and zinc-containing SOD (CuZn-SOD) show relatively mild phenotypes. To explore the possibility that the isoenzymes have partly overlapping functions, single and double knockout mice were examined. The absence of EC-SOD was found to be without effect on the lifespan of mice, and the reduced lifespan of CuZn-SOD knockouts was not further shortened by EC-SOD deficiency. The urinary excretion of isoprostanes was increased in CuZn-SOD knockout mice, and plasma thiobarbituric acid-reactive substances levels were elevated in EC-SOD knockout mice. These oxidant stress markers showed potentiated increases in the absence of both isoenzymes. Other alterations were mainly found in CuZn-SOD knockout mice, such as halved glutathione peroxidase activity in the tissues examined and increased glutathione and iron in the liver. There were no changes in tissue content of the alternative superoxide scavenger ascorbate, but there was a 25% reduction in ascorbate in blood plasma in mice lacking CuZn-SOD. No increase was found in the urinary excretion of the terminal metabolites of NO, nitrite, and nitrate in any of the genotypes. In conclusion, apart from the increases in the global urinary and plasma oxidant stress markers, our phenotype studies revealed no other evidence that the copper- and zinc-containing SOD isoenzymes have overlapping roles.     

Inactive extracellular superoxide dismutase disrupts secretion and function of active extracellular superoxide dismutase

Extracellular superoxide dismutase (EC-SOD) is an antioxidant enzyme that protects cells and tissues from extracellular damage by eliminating superoxide anion radicals produced during metabolism. Two different forms of EC-SOD exist, and their different enzyme activities are a result of different disulfide bond patterns. Although only two folding variants have been discovered so far, five folding variants are theoretically possible. Therefore, we constructed five different mutant EC-SOD expression vectors by substituting cysteine residues with serine residues and evaluated their expression levels and enzyme activities. The mutant EC-SODs were expressed at lower levels than that of wild-type EC-SOD, and all of the mutants exhibited inhibited extracellular secretion, except for C195S ECSOD. Finally, we demonstrated that co-expression of wild-type EC-SOD and any one of the mutant EC-SODs resulted in reduced secretion of wild-type EC-SOD. We speculate that mutant EC-SOD causes malfunctions in systems such as antioxidant systems and sensitizes tissues to ROS-mediated diseases.     

Anticonvulsive effect of superoxide dismutase

The influence of superoxide dismutase (SOD) on the development of focal epileptic activity (EpA) in the rat brain cortex has been investigated. Intraperitoneal administration of SOD to rats (1 mg/kg) 30 minutes before penicillin application to the sensorimotor cortex led to marked relaxation of EpA and a decrease in the concentration of lipid peroxidation (LPO) products in EpA focus. The results corroborate our earlier assumption on an important pathogenetic role of LPO disturbances in epileptogenesis and make reasonable the combination of the traditional anticonvulsive therapy with the agents activating the oxidative system.     

Effect of superoxide dismutase on the autoxidation of various hydroquinones--a possible role of superoxide dismutase as a superoxide:semiquinone oxidoreductase

The autoxidation of DT-diaphorase-reduced 1,4-naphthoquinone, 2-OH-1,4-naphthoquinone, and 2-OH-p-benzoquinone is efficiently prevented by superoxide dismutase. This effect was assessed in terms of an inhibition of NADPH oxidation (over the amount required to reduce the available quinone), O2 consumption, and H2O2 formation. Superoxide dismutase also affects the distribution of molecular products -hydroquinone/quinone-involved in autoxidation, by favoring the accumulation of the reduced form of the above quinones. In contrast, the rate of autoxidation of DT-diaphorase-reduced 1,2-naphthoquinone is enhanced by superoxide dismutase, as shown by increased rates of NADPH oxidation, O2 consumption, and H2O2 formation and by an enhanced accumulation of the oxidized product, 1,2-naphthoquinone. These findings suggest that superoxide dismutase can either prevent or enhance hydroquinone autoxidation. The former process would imply a possible new activity displayed by superoxide dismutase involving the reduction of a semiquinone by O2-.. This activity is probably restricted to the redox properties of the semiquinones under study, as indicated by the failure of superoxide dismutase to prevent autoxidation of 1,2-naphthohydroquinone.