外科加强医疗病区耐甲氧西林金黄色葡萄球菌感染的分析

通过分析我院外科加强医疗病区(SICU)感染耐甲氧西林金黄色葡萄球菌(MRSA)患者的资料,总结引起MRSA感染的危险因素。方法:回顾性调查1996年1月～1998年12月入SICU的1069例患者资料,按感染细菌分为MRSA组和非MRSA组,比较两组的发病率及病死率;比较两组患者在ICU住院时间、广谱抗生素应用、血清白蛋白含量的差异,计算各因素的优势比(OR)。结果:MRSA20例,非MRSA57例,MRSA感染患者病死率为非MRSA的1.9倍,P<0.05;MRSA感染相关因素有ICU住院时间(P=003,OR=252)、广谱抗生素的应用(P=004,OR=16.10)、低白蛋白血症(P=0.01,OR=234)。结论:MRSA感染病死率高,ICU住院时间长、应用广谱抗生素、低白蛋白血症是引起MRSA感染的危险因素。     

Conservative management of a methicillin-resistantStaphylococcus aureus (MRSA)-infected aortobifemoral graft: Report of a case

A 63-year-old man was referred to our department for treatment of intermittent claudication in the right lower limb. The preoperative angiogram showed severe stenosis extending from the terminal aorta to the bilateral common femoral arteries, with occlusion of the right superficial femoral artery and the left popliteal artery. He underwent aortobifemoral bypass with thromboendarterectomy of the left common femoral artery, and right graft-popliteal artery bypass. The patient had an uneventful postoperative course; however, 14 days after the operation, a pulsatile mass suddenly appeared in the left groin. Emergency surgery revealed disruption of the left distal anastomosis of the aortobifemoral bypass and therefore, revision, in the form of graft-profunda femoris artery interposition with graft-superficial femoral artery bypass, was performed. Microscopic examination showed colonies of bacteria in the host artery adventitia adjacent to the anastomosis. Culture of the discharge from the right groin operative scar revealed methicillin-resistantStaphylococcus aureus (MRSA). The discharge resolved following the intravenous administration of vancomycin and the local application of vancomycin ointment. There were no operative complications other than the MRSA infection, and the patient was discharged 20 days after revision surgery. In the 14 months since the revision, all grafts have remained patent and there have been no further symptoms of graft infection.     

不同温度诱导细菌L型的实验观察

目的：观察不同温度诱导细菌形成Ｌ型。方法：抗生素纸片诱导。以苯唑青霉素（每片４０μｇ）、羧苄青霉素（每片５００μｇ）在３７℃、３２℃及２８℃分别诱导金黄色葡萄球菌和福氏痢疾杆菌Ｌ型。结果：三种不同温度诱导细菌形成Ｌ型,其菌落特征、形态及染色性等均无差别。结论：抗生素诱导Ｌ型除３７℃外,３２℃和２８℃均可形成。为探讨Ｌ型可在自然界产生和存在是否与某些传染病流行和传播有关提供依据。     

Genetic basis of neonatal methicillin-resistant Staphylococcus aureus in Japan

Methicillin-resistant Staphylococcus aureus (MRSA) is still one of major problems of drug-resistant microorganisms and healthcare-acquired infections. Methicillin-resistant Staphylococcus aureus is highly prevalent in patients in neonatal intensive care units (NICU) in Japan. The most predominant MRSA in NICU is multidrug resistant and produces superantigenic exotoxin, toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin C (SEC). These predominant MRSA strains belong to coagulase type II, SCCmec type II, mecA-Tn554 polymorph type I-A and show closely related pulse field gel electrophoresis types. The dissemination of MRSA is wide, and there is a pandemic distribution of a single MRSA clone in the NICU of Japan. Since 1992, the nationwide spread of this clone has also led to the development of a new neonatal disease known as neonatal toxic shock-like exanthematous disease (NTED), which is caused by overactivation of vbeta2+ T cells induced by TSST-1. The spread of MRSA in NICU in Japan has been attributed to overcrowding, high rates of extremely low birthweight babies, understaffing, low control measures of infection and overuse of antibiotics. The environment of NICU and infection control intervention should be improved and a new strategy for control like vaccination or probiotics is required.     

耐万古霉素微生物筛选模型

为获得耐万古霉素的肠球菌和金葡球菌，利用紫外线对Enterococcus faecalis458和Staphylococcus aureus9918进行诱变，确定在不同处理中以紫外线照射30s为最佳。最后获得对万古霉素中敏的E．faecalis458 V20和S．aureus9918 V16，药物敏感性试验表明前者对青霉素G钾和红霉素耐药，而后者对青霉素G钾、红霉素、苯唑青霉素钠和氨苄青霉素钠耐药。两者对万古霉素的耐药性在无药培养基上传10代后略微下降。     

头孢硫脒等6种抗菌药物对革兰氏阳性球菌体外抗菌活性研究

目的 对比研究头孢硫脒(CTM)、头孢唑林(CEZ)、头孢映辛(CXM)、头孢曲松(CRO)、苯唑西林(MPIPC)、万古霉素(VCM)对99株临床分离革兰氏阳性球菌的抗菌活性。方法采用琼脂平板稀释法测定最低抑菌浓度(MIC)。结果 CTM对32株金黄色葡萄球菌的MIC50、MIC90均为0．5mg/L，低于CRO，CTM对29株表皮葡萄球菌的MIC50、MIC90分别为0．125和8mg/L，是CRO的l／16，对9株甲氧西林耐药的葡萄球菌(MRS)的范围与CXM相近；CTM对粪肠球菌的抗菌活性与万古霉家相仿，强于CEZ、CXM、CRO、LGIPC。结论头孢硫腺对葡萄球菌和粪肠球菌具有很强的体外抗菌活性。     

Molekulare und phänotypische Charakterisierung von Methicillin-resistenten Staphylococcus-aureus-Isolaten Untersuchungen an einer Unfallchirurgischen Klinik von 1994–1997

Methicillin resistant Staphylococcus aureus-strains, isolated from 1994 to 1997 from patients of the traumatic surgery hospital Tübingen, were compared using lysotyping and pulsed-field gel electrophoresis. Both typing methods detected two clones causing an outbreak 1994 in 6 patients and a third endemic clone of MRSA, which was isolated from 5 patients (1995), 4 patients (1996), and 6 patients (1997). Additionally other MRSA-types were found in 6 cases of which transmissions occurred in up to three patients. An epidemiological connection to MRSA isolated from patients of the university hospital of Tübingen was made. Possible consequences for patient management and antibiotic strategies in MRSA-infections were discussed.     

头孢硫脒与6种抗菌药物联用对金葡球菌的体外抗菌活性

目的:评价头孢硫脒分别与万古霉素、奈替米星、阿米卡星、环丙沙星、左氧氟沙星和加替沙星6种抗菌药物联合用药,对于临床分离的金葡球菌(SA)的体外联合抗菌效应.方法:经VITEK鉴定临床分离致病菌,采用棋盘法设计,微量肉汤稀释法测定6组抗菌药物对SA及耐甲氧西林金葡球菌(MRSA)的最低抑菌浓度,并计算部分抑菌指数(FIC指数). 结果:头孢硫脒与万古霉素、奈替米星、阿米卡星、环丙沙星、左氧氟沙星、加替沙星联合应用后,MIC50,MIC90明显降低,FIC指数<0.5占60%～90%,0.5～1占10%～30%,1～2占0～13.3%,>2为0.结论:头孢硫脒与6种抗菌药物联合应用后,对SA基本表现为协同和相加作用,说明联合用药的疗效要高于两药单独使用.     

黄连与黄芩、甘草配伍前后对金黄色葡萄球菌生长抑制作用的观察

以ＭＩＣ相对值为指标，观察黄连、黄芩、甘草煎液单味或不同比例配伍后对金黄色葡萄球菌生长的抑制作用。结果显示：黄连与黄芩配伍，黄芩的抑菌作用有所降低，但黄连则未见降低；黄芩多于黄连时，黄连的抑菌作用似有增强。黄连与甘草配伍，无论比例如何，配伍后的抑菌作用均呈降低趋势。当三药同时配伍时，黄连、甘草的抑菌作用不变，或反增强，只有黄芩的抑菌作用有减弱趋势。黄连与黄芩、甘草两两配伍，单独使用时，其抑菌作用似不如组成三药配伍。其机制值得进一步研究。     

金黄色葡萄球菌norA基因的研究

目的 研究norA基因介导的金葡菌对氟喹诺酮类药物的耐药机制。方法PCR法制备DIG-norA基因探针；点杂交及狭线杂交检测细菌nor4基因及其转录水平。结果所有实验菌株均检测到norA基因；诱导耐药菌SA2-16的norA基因转录水平明显高于其亲代株，临床分离耐药菌norA基因转录水平略高于敏感菌，但统计学分析无显著性差异，细菌在环丙沙星1／10MIC浓度中生长，未见norA基因转录增加。结论 norA基因可能为金葡菌的结构基因，诱导耐药菌药物泵出增加的原因在于norA基因转录的增加，norA基因介导的耐药在不同的耐药菌株中所起的作用并不相同。