耐甲氧西林金黄色葡萄球菌杀白细胞素基因检测

目的 调查临床分离的耐甲氧西林金黄色葡萄球菌(MRSA)杀白细胞毒素基因携带率。方法 收集非重复MRSA菌株83株,按照美国疾病预防控制中心的CA-MRSA 定义分为HA-MRSA和CA-MRSA两组。采用多重PCR法进行SCCmec分型,普通PCR+测序法进行spa分型,普通PCR检测杀白细胞素(PVL)基因。结果 83株MRSA中HA-MRSA、CA-MRSA分别占47.0%、53.0%,SCCmec分型中SCCmecⅠ、Ⅱ、Ⅲ、Ⅳa型和未分型各占1.2%、3.6%、65.1%、28.9%、1.2%,spa分型中83株MRSA共检出15个型,主要分型为t437,t062,t015分别占39.8%, 21.7%,10.8%;PVL阳性的MRSA中HA-MRSA和CA-MRSA分别10.3%、36.4%,两者差异有显著性(P=0.006);33株spa t437中有18株携带PVL基因,阳性率54.5%,50株其他spa分型中仅2株携带PVL基因,阳性率4.0%,两者差异有显著性(P=0.000)。PVL基因阳性的MRSA特征CA-MRSA-Ⅳa-t437 9株,HA-MRSA-Ⅲ-t437 4株,HA-MRSA-Ⅳa-t437 3株;20株PVL基因阳性的MRSA中10株分离自皮肤软组织感染病例,6株分离于耳鼻喉科感染病例,3株分离于呼吸道感染病例,1株分离于败血症病例。结论 CA-MRSA菌株较HA-MRSA菌株的 PVL基因阳性率更高,同时也发现携带有更高毒力的CA-MRSA的克隆已经播散到医院的环境中,引起医院获得性相关感染。     

引起皮肤软组织感染的杀白细胞素阳性社区获得性耐甲氧西林金黄色葡萄球菌分子特征研究

目的 了解分离自临床皮肤和软组织感染(SSTIs)患者携带杀白细胞素基因(pvl)社区获得性耐甲氧西林金黄色葡萄球菌(pvl⁺-CA-MRSA)的分子特征。方法 从SSTIs患者中分离出92株CA-MRSA。采用聚合酶链反应(PCR)和测序检测pvl基因及其突变。pvl⁺-CA-MRSA菌株进行序列类型(STs)与克隆复合物(CCs)、葡萄球菌盒式染色体mec(SCCmec)、葡萄球菌蛋白基因(spa)多态性、辅助基因调控子(agr)位点、脉冲场凝胶电泳(PFGE)分型和多位点序列分型(MLST)。采用VITEK-2 Compact全自动微生物鉴定系统进行CA-MRSA药物敏感试验。结果 92株CA-MRSA中,24株(26.1%)为pvl⁺-CA-MRSA,其中91.7%(22/24)为pvl的H亚型,68株(73.9%)为未携带pvl基因CA-MRSA(pvl^--CA-MRSA)。24株pvl⁺-CA-MRSA中,共有8种STs和7种CCs,其中以ST59(62.5%,15...     

耐甲氧西林金黄色葡萄球菌杀白细胞素基因亚型的流行及MLST分子分型

目的 探讨临床分离的耐甲氧西林金黄色葡萄球菌(MRSA)杀白细胞素(pvl)基因亚型的流行及MLST分子分型特征.方法 收集非重复MRSA 287株,按照美国疾病预防控制中心的社区获得性耐甲氧西林金黄色葡萄球菌(CA-MR-SA)定义分为医院获得性耐甲氧西林金黄色葡萄球菌(HA-MRSA)和CA-MRSA两组.采用PC...     

重组金黄色葡萄球菌杀白细胞毒素对人肺泡巨噬细胞细胞因子表达的影响

目的 应用体外培养人肺泡巨噬细胞(AM),观察重组金黄色葡萄球菌杀白细胞毒素(rPVL)对AM的CD14白细胞介素(IL)-10及肿瘤坏死因子(TNF)-α表达的影响.方法 从患者BALF中分离纯化AM,根据作用时间及rPVL浓度不同分为T0N0组[T为时间(h),N为毒素浓度(nmol/L)]、T6N0组、T6N10组、T6N100组、T24N0组、T24N10组、T24N100组共7组.半定量逆转录PCR法测定AM的CD14mRNA水平,双抗夹心ELISA法测定AM培养液上清IL-10及TNF-α浓度.结果 rPVL作用后AM的CD14mRNA下降,降低幅度随时间延长和毒素浓度升高而增加.3组空白对照组间差异无统计学意义(F=1.708,P>0.05).T6N10、T6N100组均较T6 N0组低(t=4.132、6.818,均P<0.001);T6N10、T24N100组均较T24N0组低(t=7.401、11.415,均P<0.001),表明毒素作用后CD14表达量降低.T24N10组低于T6N10组、T24N100组低于T6N100组(t=4.692、6.019,均P<0.001),表明毒素作用后CD14mRNA随时间延长而降低.T6N100组低于T6N10组、T24N100组低于T24N10组(t=2.686、4.014,均P<0.05),表明CD14mRNA随毒素浓度升高而降低.IL-10浓度T24N10、T24N100组均高于T24N0组(t=4.036、3.941,均P<0.01),表明IL-10的释放随毒素浓度增加和作用时间延长而增加.TNF-α浓度T24N10组低于T24N0组,而T24N100组高于T24N0组(t=2.824、8.468,均P<0.01),表明低浓度毒素可抑制TNF-α释放而高浓度毒素诱导其大量释放.结论 rPVL致AM的CD14表达下降并致AM促炎和抗炎因子表达异常,可致AM功能缺陷引起宿主免疫抑制,不利于炎性细胞对病原菌的清除,可能是杀白细胞毒素金黄色葡萄球菌感染,尤其是重症坏死性肺炎病死率高的重要原因之一.     

金黄色葡萄球菌的粘附素

金黄色葡萄球菌的粘附素陈怀青综述陆承平审校金黄色葡萄球菌是创伤感染中最常见的病原菌，而且可引致败血症、疖、脓肿等。作为人兽共患病的重要病原菌，其致病性长期来为医学家所关注。但以往主要对凝固酶、葡激酶等胞外酶及肠毒素、杀白细胞毒、表皮剥脱毒素以及毒性休...     

多形核粒细胞在金黄色葡萄球菌杀白细胞素相关肺炎性损伤中的作用

目的 探讨多形核粒细胞(PMN)在金黄色葡萄球菌Panton Valentine杀白细胞素(PVL)介导的肺炎性损伤中的作用.方法 取15只新西兰大白兔均分为3组,构建肺炎性损伤模型.对照组使用PBS灌肺,粒细胞正常兔直接用重组PVL灌肺(rPVL组),粒细胞减少症兔先用长春新碱(VCR)处理,再用rPVL灌肺(VCR+rPVL组).造模后9h,计数外周血和支气管肺泡灌洗液(BALF)中PMN,同时检测BALF上清液中乳酸脱氢酶(LDH)含量、肺通透指数(LPI),BALF中PMN凋亡率、坏死率、活性氧自由基(ROS)释放量.取肺组织检测肺湿干比,并进行病理学检查.组间比较采用t检验.结果 rPVL组外周血PMN为(2.69±0.34)×106/mL,显著低于对照组的(3.63±0.38)×106/mL(t=4.12,P＜0.05).对照组、rPVL组和VCR+rPVL组BALF中PMN分别为(0.57±0.01)×106/mL、(3.01±0.02)×106/mL和(0.10±0.02)×106/mL,rPVL组显著高于对照组(t=254.39,P＜0.05).rPVL组兔LDH、LPI和肺湿重/干重比均显著高于对照组,但后者与VCR+rPVL组比较,差异无统计学意义.rPVL组BALF中PMN晚期凋亡率和坏死率分别为( 18.98±1.04)％、(63.56±3.53)％,对照组分别为(1.03±0.17)％、(0.95± 0.33)％(t=38.24,39.48;均P＜0.05),VCR+rPVL组凋亡率和坏死率分别为(1.17=0.24)％、(1.1 3±0.17)％.rPVL组、对照组和VCR+rPVL组ROS分别为1.56±0.39、0.41±0.03和0.39±0.02,rPVL组明显升高(t=6.58,P＜0.05).rPVL组肺组织有弥漫性炎性细胞浸润、出血、水肿,VCR+rPVL组仅见支气管周围与肺泡间隔极少量炎性细胞浸润.结论 rPVL可引起粒细胞正常兔肺炎性损伤,但对粒细胞减少症兔肺损伤极小.PVL引起肺炎性损伤可能是依赖PMN的招募和聚集,继而坏死和(或)激活,释放细胞毒素颗粒内容物和(或)活性氧代谢产物等.     

金黄色葡萄球菌肺部感染的临床分析

目的了解我院金黄色葡萄球菌肺部感染的耐药趋势及用药情况，供临床治疗参考。方法对临床分离出的金黄色葡萄球菌进行药物敏感试验，并统计临床用药情况、疗程及预后。结果金黄色葡萄球菌肺部感染多为老年发病、住院时间长、病死率高。659例肺部感染中检出金黄色葡萄球菌33例，耐甲氧西林金黄色葡萄球菌（MRSA）22例，万古霉素敏感率为71.4％、其次为头孢哌酮／舒巴坦、阿米卡星、头孢曲松敏感率／〉50％，氧氟沙星、环丙沙星其敏感性最低。而临床上敏感率最高的万古霉素用药频率却为最低。结论目前万古霉素仍然是耐甲氧西林金黄色葡萄球菌肺部感染的首选药物，但是临床的用药情并非如此，证明临床对耐甲氧西林金黄色葡萄球菌肺部感染重视程度不够，值得关注。     

血液透析患者金黄色葡萄球菌感染

金黄色葡萄球菌(staphylococcus aureus,SA)广泛存在于人体,侵袭力强,可以耐受各种极端环境,并以不同形式出现,可长期寄居于患者组织中而不引起临床症状,也可导致暴发性全身感染.血液透析(HD)患者存在局部或系统性易感因素,SA感染发生率高,本文将对HD患者SA感染的发生机制及防治作一简述.     

金黄色葡萄球菌医院内感染的危险因素

随着医疗技术水平的不断提高 ,免疫抑制剂的使用 ,肿瘤及危重患者的增加 ,不仅使金黄色葡萄球菌医院内感染的患者增加 ,而且耐甲氧西林金黄色葡萄球菌 (ＭＲＳＡ)的感染也逐渐增多。现将 3所综合性医院金黄色葡萄球菌医院内感染的临床流行病学调查情况报道如下。材料与方法一、研究对象病例组选择 :1997年 10月至 1999年 4月广州市 3所综合性医院住院患者 ,临床标本确定为金黄色葡萄球菌 ,根据标本确定为医院内感染病例 ,资料完整者共 10 8例。对照组选择 :配比条件为相同性别、民族、病区 ;住院时间前后不超过 1个月 ,无金黄色葡萄球菌感染…     

致皮肤软组织感染社区获得性金黄色葡萄球菌的分子生物特征分析

目的了解解放军总医院第一附属医院致皮肤软组织感染社区获得性金黄色葡萄球菌(CA-SA)的流行情况、耐药特点、毒力和致病因素信息。方法收集2009年1月至2010年8月皮肤科、门诊、急诊55例患者化脓性皮肤软组织感染检测标本,进行细菌鉴定和药敏试验,采用多位点序列分型(MIST)、金黄色葡萄球菌A蛋白(SPA)分型和毒素基因检测筛查。结果 55例中分离到社区获得性甲氧西林敏感的金黄色葡萄球菌(CA-MSSA)12株;药敏结果显示CA-MSSA除对红霉素、克林霉素、四环素、庆大霉素和左氧氟沙星耐药性较高(8.3%~50.0%),对其他抗菌药物均敏感。毒素基因检测显示杀白细胞素(pvl)、肠毒素C(sec)和毒性休克综合征毒素-1(tsst-1)在CA-MSSA中的阳性率分别为33.3%,25.0%和8.3%,未检测到葡萄球菌肠毒素H(seh)和葡萄球菌表皮剥脱毒素(et);结合MLST和SPA分型,发现CA-MSSA中的克隆有ST5-t002(2株)、ST22-t309(2株)及ST398-t034、ST15-t5864、ST7-t091、ST25-t078、ST30-t318、ST121-t1425、ST800-t1425、ST630-t377各1株。结论我院致皮肤软组织感染CA-MSSA菌株对抗菌药物的敏感性较高,分子分型具有多样性,携带多种毒素。     

Severe non-pneumonic necrotising infections in children caused by Panton-Valentine leukocidin producing Staphylococcus aureus strains

Two cases of infection with Panton-Valentine Leukocidin (PVL) producing strains of Staphylococcus aureus are reported. A 15-year-old insulin dependent diabetic developed toxic shock syndrome and an abscess in the deep tissue around his left hip. A 34-day-old infant presented with a right orbital cellulitis with an intra-orbital collection and septicaemia. In both cases PVL-producing strains of Staphylococcus aureus were isolated. Both surgery and prolonged antibiotic combination regimens were required to eradicate the infection. The cases reported here demonstrate the wide range of clinical presentations seen with PVL producing strains, which have so far been mainly associated with furuncles and necrotising pneumonia.     

Panton-Valentine leukocidin-producing Staphylococcus aureus infections: report of 4 French cases

We report 4 cases of community-acquired infections due to Staphylococcus aureus producing Panton-Valentin leukocidin (SA-PVL) with uncommon multivisceral localizations. These cases highlight the need to screen for PVL in patients with serious staphylococcal infections. All patients were cured. Two of them received intravenous immunoglobulins in addition to antibiotics.     

Involvement of Panton-Valentine leukocidin-producing Staphylococcus aureus in primary skin infections and pneumonia.

Panton-Valentine leukocidin (PVL) is a cytotoxin that causes leukocyte destruction and tissue necrosis. It is produced by fewer than 5% of Staphylococcus aureus strains. A collection of 172 S. aureus strains were screened for PVL genes by polymerase chain reaction amplification. PVL genes were detected in 93% of strains associated with furunculosis and in 85% of those associated with severe necrotic hemorrhagic pneumonia (all community-acquired). They were detected in 55% of cellulitis strains, 50% of cutaneous abscess strains, 23% of osteomyelitis strains, and 13% of finger-pulp-infection strains. PVL genes were not detected in strains responsible for other infections, such as infective endocarditis, mediastinitis, hospital-acquired pneumonia, urinary tract infection, and enterocolitis, or in those associated with toxic-shock syndrome. It thus appears that PVL is mainly associated with necrotic lesions involving the skin or mucosa.     

Treatment of methicillin-resistant Staphylococcus aureus infections:Importance of high vancomycin minumum inhibitory concentrations

Staphylococcus aureus(SA) infections remain a major cause of morbidity and mortality despite the availability of numerous effective anti-staphylococcal antibiotics.This organism is responsible for both nosocomial and community-acquired infections ranging from relatively minor skin and soft tissue infections to life-threateningsystemic infections.The increasing incidence of methicillin-resistant strains has granted an increasing use of vancomycin causing a covert progressive increase of its minimum inhibitory concentration(MIC)(dubbed the MIC "creep").In this way,the emergence of vancomycinintermediate SA(VISA) strains and heteroresistantVISA has raised concern for the scarcity of alternative treatment options.Equally alarming,though fortunately less frequent,is the emergence of vancomycin-resistant SA.These strains show different mechanisms of resistance but have similar problems in terms of therapeutic approach.Ultimately,various debate issues have arisen regarding the emergence of SA strains with a minimum inhibitory concentration sitting on the superior limit of the sensitivity range(i.e.,MIC = 2 μg/mL).These strains have shown certain resilience to vancomycin and a different clinical behaviour regardless of vancomycin use,both in methicillin-resistant SA and in methicillin-sensitive SA.The aim of this text is to revise the clinical impact and consequences of the emergence of reduced vancomycin susceptibility SA strains,and the different optimal treatment options known.     

Staphylococcus aureus bloodstream infections: the association between age and mortality and functional status

OBJECTIVES: To assess the association between Staphylococcus aureus (S. aureus) blood stream infections (BSIs) and morbidity and mortality in older adults. DESIGN: Retrospective review. SETTING: Veterans Affairs Ann Arbor Healthcare System. PARTICIPANTS: All patients with S. aureus BSI during 2004/05. MEASUREMENTS: Outcomes included in‐hospital and 6‐month mortality, as well as need for subacute care. RESULTS: Sixty‐eight patients with S. aureus BSI were identified (mean age 63.5±13.0). Outcomes of interest included in‐hospital mortality (19.1%), 6‐month mortality (33.8%), and need for subacute care (65.4%). Univariate analysis identified several predictors of death, including older age, chronic renal insufficiency, catheter‐related infection, Charlson weighted index of comorbidity score, and infection with methicillin‐resistant S. aureus (MRSA). Multivariable analysis demonstrated that older age (odds ratio (OR)=1.1, P<.01), chronic renal insufficiency (OR=16.6, P=.01), and MRSA infection (OR=5.1, P=.03) were independently associated with 6‐month mortality. These results suggest that, for every decade increase in age, the odds of death within 6 months of S. aureus BSI doubles (OR=1.1). Chronic renal insufficiency was also independently associated with in‐hospital mortality. Of the previously community‐dwelling patients (n=50), 41 survived hospitalization, of whom 22 (53.7%) required subacute care after discharge. CONCLUSION: Better understanding of the epidemiology of S. aureus BSI in older patients and validation of risk factors for poor functional outcomes and death should be the focus of future prospective studies.     

耐甲氧西林金黄色葡萄球菌（MRSA）感染机制研究进展

耐甲氧西林金黄色葡萄球菌（MRSA）是一种新型金黄色葡萄球菌,它会造成严重感染性疾病。MRSA对p内酰胺类抗生素耐药性的产生及毒力的加强使得它成为了临床治疗的-大痼疾。一些虽然低效但较少产生耐药的抗生素的出现使得MRSA治疗有了新的选择。同时,研究者正在逐渐阐明MRSA基因突变和病原学特征（耐药性、毒力等）的相关性。这些成果都将为今后MRSA的临床治疗以及新药和疫苗的开发提供宝贵的理论支持与指导。     

下呼吸道感染金葡菌耐药性分析

目的调查我院住院病人下呼吸道感染金黄色葡萄球菌（SA）的耐药现状。方法对101例下呼吸道感染sA的住院病人临床资料进行分析,并比较甲氧西林敏感金黄色葡萄球菌（MSSA）与耐甲氧西林金黄色葡萄球菌（MRSA）对抗生素的耐药性差异。结果共101例下呼吸道感染患者,分离出MRSA71例,分离率70．30％。下呼吸道sA感染发生于基础疾病较多,接受侵入性操作,长时间使用抗生素的患者;药敏结果显示,MRSA对多种抗菌药物的产生高度耐药,且耐药率明显高于MSSA（P〈0．01）,但对替加环素、万古霉素、利奈唑胺敏感率为100％。结论下呼吸道感染sA多发生于危险因素较多的患者;MRSA分离率高,对常用抗菌药物呈多重耐药。