金黄色葡萄球菌食物中毒株遗传特征分析

目的对石家庄市2007-2013年金黄色葡萄球菌食物中毒株进行分子分型、肠毒素检测和耐药性分析,了解金黄色葡萄球菌食物中毒株的遗传学特征。方法利用多位点序列分型(MLST)技术对食物中毒事件中检出的金黄色葡萄球菌进行分子分型,采用金黄色葡萄球菌肠毒素ABCDE分型检测试剂盒对分离的金黄色葡萄球菌进行葡萄球菌肠毒素分型,采用BD Phoenix?生化药敏鉴定仪对分离株进行药敏检测。结果 47株食物中毒株金黄色葡萄球菌分14个MLST型,分别为:ST15、ST59、ST5、ST398、ST6、ST1003、ST88、ST30、ST338、ST464、ST7、ST72、ST804和ST9。葡萄球菌肠毒素类型分别为SEE,SEA-SEB-SEC,SEA-SED-SEE,SEB-SEC,SEC-SED-SEE,SEA-SEE和SEASEB-SED-SEE。93.6%(44/47)的食物中毒株产β-内酰胺酶,97.9%(46/47)的分离菌株对青霉素耐药,对其他11种受试药物表现出不同程度的敏感,少数菌株表现为耐药。结论多个MLST型的金黄色葡萄球菌均可引起食物中毒,食物中毒株可产多种葡萄球菌肠毒素,对多种抗菌药物敏感。     

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。     

耐甲氧西林金黄色葡萄球菌SCCmec分型的研究

目的探究我院耐甲氧西林金黄色葡萄球菌的SCCmec基因的分型情况。方法选取我院2009年1月～12月收集的108株金黄色葡萄球菌,采取琼脂筛选法进行检测mecA基因,然后采取多重PCR方法对耐甲氧西林金黄色葡萄球菌的SC-Cmec基因进行分型,并采取K-B纸片扩散法进行药敏实验。结果有32株金黄色葡萄球菌检查为阳性,均为耐甲氧西林金黄色葡萄球菌(阳性率为29.6%)。而SCCmec基因分型主要表现2株为SCCmecⅡ型菌株(6.3%),26株为SCCmecⅢ型菌株(81.3%),2株为SCCmecⅣ型菌株(6.3%),出现有2株菌株未分型(6.3%)。结论分离我院耐甲氧西林金黄色葡萄球菌的SCCmec基因分型主要以SCCmecⅢ型菌株为主,多重PCR方法检查具有较高的准确性。     

金黄色葡萄球菌医院感染及耐药分析

目的了解金黄色葡萄球菌感染的特点及其对抗菌药物的耐药性,为临床治疗金黄色葡萄球菌感染提供选药依据。方法对2012-01~2014-06该院临床分离出的196株金黄色葡萄球菌进行常规培养分离鉴定,药敏试验应用K-B纸片扩散法,按国家临床实验室标准委员会/美国临床实验室准化委员会(CLSI/NCCLS)规定的标准进行细菌鉴定和药敏检测。结果共分离出耐甲氧西林金黄色葡萄球菌(MRSA)91株(46.4%),甲氧西林敏感金黄色葡萄球菌(MSSA)105株(53.6%)。其中MRSA主要来源于呼吸内科,以老年患者为主。MRSA及MSSA对万古霉素、利奈唑胺、替考拉宁均敏感。MRSA对氨苄西林、苯唑西林、青霉素G、头孢唑林、头孢西丁的耐药率为100%,MSSA耐药率由高至低依次为青霉素G、氨苄西林、红霉素。MRSA对各种抗菌药物的耐药率均高于MSSA,差异有统计学意义(P0.01)。结论 MSSA和MRSA对抗菌药物耐药率不同,须重视金黄色葡萄球菌的耐药监测,控制耐药菌株,更好地指导临床合理选用抗生素。     

生猪养殖环境及猪肉中金黄色葡萄菌肠毒素基因分布研究

目的 了解猪养殖场和市售生鲜猪肉分离的金黄色葡萄球菌的肠毒素基因携带情况。方法 采用PCR方法检测sea、seb、sec、sed、see、seg、seh、sei、sej、sek、sel、sem、sen、seo、sep、seq、ser、seu 18个肠毒素基因在金黄色葡萄球菌中的分布状况。结果从130株金黄色葡萄球菌中,共检测到94.6%(123/130)的菌株携带有肠毒素基因,以seb的检出率最高,占60.8%,其中养殖场分离的金黄色葡萄球菌55%(55/100)、市售生鲜猪肉分离的金黄色葡萄球菌80%(24/30);养殖场分离株中检测到的肠毒素基因型主要有seb+seg+sem+sen、 seg+sem、seg+sei+sem+sen、seg+sem+sen 和seb+seg+sei+sem+sen,其检出率分别为8.0%(8/100)、7.0%(7/100)、7.0%(7/100)和6.0%(6/100);市售生鲜猪肉分离株中检测到的肠毒素基因型主要有sea+seb+see、sea+seb 、seb+see和sea+see+sem,其检出率分别为30%(9/30)、10%(3/30)、10%(3/30)和6.7%(2/30)。养殖场和市售生鲜猪肉分离株中均未检测到sed、sej、seo、sep、seq、ser和seu基因。结论 猪养殖场和市售生鲜猪肉分离的金黄色葡萄球菌均有携带肠毒素基因,且在型别上有一定的差异,可能存在不同的污染来源,这对监控猪养殖场和市售生鲜猪肉中金黄色葡萄球菌的污染及肠毒素基因的携带状况具有一定意义。     

2012～2013年金黄色葡萄球菌临床分布及耐药性

目的了解该院金黄色葡萄球菌的临床分布及耐药性变迁。方法 2012~2013年临床分离的金黄色葡萄球菌,采用美国临床实验室标准化委员会(CLSI)推荐的方法(K-B法)进行药敏试验和结果判断。结果 2012年分离的226株金黄色葡萄球菌主要来源于重症医学科(24.34%)和康复医学科(16.37%),耐甲氧西林金黄色葡萄球菌(MRSA)检出率为23.45%;2013年分离的244株金黄色葡萄球菌主要来源于重症医学科(32.79%)和神经外科(13.52%),MRSA检出率为33.20%。感染标本来源最多的是呼吸道标本,2012年占69.03%,2013年占59.43%;金黄色葡萄球菌对青霉素G、红霉素、克林霉素耐药率较高,2012~2013年均未发现对万古霉素、替考拉宁、利奈唑胺、替加环素耐药株。结论金黄色葡萄球菌是呼吸道感染最常见的病原菌之一,主要来源于重症医学科。临床医师应依据细菌药敏结果,合理选择抗菌药物,预防和控制耐药菌的发生。     

社区获得性耐甲氧西林金黄色葡萄球菌

社区获得性耐甲氧西林金黄色葡萄球菌是社区感染中重要的致病菌之一,以往由其所致感染多发生在医院环境,如今其引起的社区感染的比例不断上升.自1961年发现第1株耐甲氧西林金黄色葡萄球菌以来,耐甲氧西林金黄色葡萄球菌在世界各地流行并引起暴发流行,耐药程度不断加重.尤其1996年万古霉素不敏感金黄色葡萄球菌及2002年耐万古霉素金黄色葡萄球菌的出现,显示其对人类的威胁愈趋严重,已成为当今感染医学一个难题.本文介绍社区获得性耐甲氧西林金黄色葡萄球菌的流行情况及防治措施.     

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%,15/24)和CC59(70.8%,17/24)为主。pvl⁺-CA-MRSA菌株中,SCCmec III和IVa型分别为54.2%和33.3%,agrI(87.5%,21/24)为最常见的agr等位基因,其余为agr III;检出8种spa型,其中以t437型最为常见(66.7%,16/24)。pvl⁺-CA- MRSA菌株对红霉素、克林霉素、四环素耐药率较高(均>50%),对复方新诺明、环丙沙星、庆大霉素的耐药率较低(8.3%~16.7%),未发现万古霉素、利福平、莫西沙星和利奈唑啶耐药菌株。与pvl⁺-CA-MRSA相比,pvl^--CA-MRSA对四环素耐药率较低(P<0.05),对其它抗菌药物耐药率差异无统计学意义(P>0.05)。结论 引起SSTIs的CA-MRSA中有较高的pvl基因阳性率,pvlH2、ST59/CC59、SCCmec III/IVa、agrI和t437是引起SSTIs CA-MRSA的优势克隆。     

流感后CA-MRSA肺炎6例分子流行病学及临床特征分析

目的分析流感后社区获得性耐甲氧西林金黄色葡萄球菌(CA-MRSA)感染病例的分子流行病学及临床特征。方法回顾性分析2014—2022年6例流感后CA-MRSA肺炎的病例, 分离培养6株CA-MRSA, 进行3种分子流行病学分型(SCCmec分型、MLST分型及spa分型)、检测其毒力因子并进行药物敏感性实验;总结病例临床特征及诊疗过程。结果 6株CA-MRSA中ST59-t437-Ⅳ型为主要分型(2/6);杀白细胞素(PVL)检出5例, 溶血素α(HLAα)及酚溶性调节蛋白α(PSMα)检出6例。6例患者中5例为重症肺炎;治疗上, 4例接受过抗病毒治疗, 5例重症肺炎患者均首选万古霉素抗感染治疗且病情好转出院。结论流感后的CA-MRSA分子分型及携带的毒力因子多样;流感后继发CA-MRSA感染更常见于年轻、既往无基础疾病人群, 可引起重症肺炎。流感后合并重症肺炎患者需要及时送病原学检测明确是否为CA-MRSA感染, 给予抗流感病毒及抗CA-MRSA感染治疗。     

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...     

宁波副溶血性弧菌临床株毒力基因与多位点序列分型研究

目的 了解宁波地区副溶血性弧菌临床分离株毒力基因分布以及分子分型特征。方法 收集来源于食物中毒和散发腹泻患者副溶血弧菌菌株,利用聚合酶链式反应(polymerase chain reaction,PCR)检测耐热直接溶血素基因(tdh)和耐热直接溶血素相关溶血素基因(trh),利用多位点序列分型(multi-locus sequence typing, MLST)进行分子分型。结果 2006—2012年共分离临床株248株,选择48株进行毒力基因和MLST分型研究。42株tdh+,为93.75%;11株trh+,为22.92%。48株菌株可分为9个ST型和一个未分型,ST3有32株,占66.67%; ST265有5株,占10.42%;ST120有3株,占6.25%。ST3克隆群中tdh+/trh-菌株有25株,占78.16%。与全国其他地区比较,在宁波临床株中发现ST262。结论 tdh+型是宁波地区副溶血性弧菌优势菌株。有9种ST型,以ST3克隆为主,其次为ST265和ST120。ST3克隆中以tdh+/trh-型为主。另发现1个独特的ST262菌株。     

Comparison of both clinical features and mortality risk associated with bacteremia due to community-acquired methicillin-resistant Staphylococcus aureus and methicillin-susceptible S. aureus.

BACKGROUND: The majority of research about community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection has focused on skin and soft-tissue infections. No literature has been published on the clinical features and outcomes of adult patients with CA-MRSA bacteremia in comparison with patients with community-acquired methicillin-susceptible S. aureus (CA-MSSA) bacteremia. METHODS: From 1 January 2001 through 31 December 2006, the demographic data and outcome of 215 consecutive adult patients admitted to a tertiary care center in Taiwan with S. aureus bacteremia (age, >16 years) who fulfilled the criteria for community-acquired S. aureus bacteremia were collected for analysis. RESULTS: The mean age (+/-SD) was 56.8+/-20.5 years. There were 30 patients (14%) with CA-MRSA bacteremia and 185 (86%) patients with CA-MSSA bacteremia. Cutaneous abscess (odds ratio, 5.46; 95% confidence interval, 1.66-17.94) and necrotizing pneumonia (odds ratio, 24.81; 95% confidence interval, 2.63-234.03) were the independent predictors of CA-MRSA bacteremia; endovascular infection was the only independent predictor of CA-MSSA bacteremia. After Cox regression analysis, the independent significant risk factors for 30-day mortality included increased age, shock, and thrombocytopenia (<100,000 cells/microL). After adjustment, the day 30 mortality of patients with CA-MRSA bacteremia was not significantly higher than that of patients with CA-MSSA bacteremia (adjusted hazard ratio, 1.01; 95% confidence interval, 0.30-3.39; P = .986). Most (92%) of 25 available CA-MRSA isolates were multilocus sequence typing 59. CONCLUSIONS: The number of adult patients with CA-MRSA bacteremia increased with time, and the disease was associated with more necrotizing pneumonia and cutaneous abscess but less endovascular infection than was CA-MSSA bacteremia. Patients with CA-MRSA bacteremia did not have higher mortality than did patients with CA-MSSA, even though most of the patients with CA-MRSA bacteremia did not receive empirical glycopeptide therapy.     

福建省2012-2018年布鲁氏菌分离株的MLST分型

目的 探讨2012-2018年福建省布鲁氏菌分离株种群结构及遗传进化关系。方法 采用多位点序列分型(Multilocus sequence typing,MLST)对43 株布鲁氏菌分离株的9 个基因位点的序列进行测定,与标准序列比对后确定菌株ST型,通过Bionumerics 6.6软件对其进行聚类分析。结果 43 株布鲁氏菌分离株中,38 株为ST8型,5 株为ST17型。结论 福建省布鲁氏菌主要流行株为ST8型。MLST是研究布鲁氏菌遗传特征的重要方法。     

Usefulness of the restriction-modification test plus staphylococcal cassette chromosome mec types and Panton-Valentine leukocidin encoding phages to identify Staphylococcus aureus methicillin-resistant clones

We studied the usefulness of the restriction-modification (RM) test, staphylococcal cassette chromosome (SCC) mec types, and Panton-Valentine leukocidin (PVL)-encoding phages to identify Staphylococcus aureus methicillin-resistant lineages and to differentiate clones that belong to the same lineage. A total of 108 methicillin-resistant S. aureus (MRSA) strains were characterized by pulsed-field gel electrophoresis (PFGE)--multi-locus sequence typing (MLST)--spa-typing. The RM correctly identified the lineages CC5, CC8, CC30, and CC398, but not CC25 and CC72. The SCCmec and RM combined analysis allowed differentiation between MLST types within the same lineage. Only 5 MRSA strains were PVL-positive. Four PVL-positive USA300 isolates carried elongated-head type PVL-encoding phages, while the sequence type (ST)-30 strain carried an icosahedral-head phage. The combination of the RM test method, SCCmec types, and PVL phage identification could be useful for MRSA typing purposes.     

非O157产志贺毒素大肠杆菌分离株的多位点序列分型研究

目的 对国内部分地区非O157产志贺毒素大肠杆菌分离株进行分子分型分析,了解菌株间的遗传进化关系。 方法 根据mlst.ucc.ie数据库提供的大肠杆菌多位点序列分型（Multilocus Sequence Typing, MLST）方案,对来自我国河南、黑龙江2省的29株产志贺毒素大肠杆菌分离株的7个管家基因进行PCR扩增并测序,通过序列比对确定其等位基因谱及菌株序列型（Sequence type, ST）,使用MEGA、eBURST生物信息软件分析不同ST序列群及菌株间的进化关系。结果 29株非O157产志贺毒素大肠杆菌呈现较大的遗传多态性,可分为13个ST型别,其中ST155为优势型别（34.48%）。同时研究发现2个新等位基因型（fumC376、recA214）和3个新序列型（ST2460、ST2467、ST2468）。结论 29株非O157产志贺毒素大肠杆菌菌株之间具有分子多态性,与国际流行菌株具有一定的亲缘关系。加强我国对这一类菌株的检测和监测具有重要的公共卫生意义。     

杭州地区单核细胞增生李斯特菌食品分离株分子型别研究

目的研究杭州地区单核细胞增生李斯特菌(Listeria monocytogenes)食品分离株的分子分型情况,了解当地流行株的型别特征。方法用脉冲场凝胶电泳(PFGE)和多位点序列分型(MLST)的方法对单核细胞增生李斯特菌进行分子分型。PFGE结果进行聚类分析,并绘制MLST数据的最小生成树。结果 6个血清型组成的133株杭州食品分离株共获得19个MLST型别,并发现1个新的ST型ST767。ST9和ST121是数量最多的型别。用AscI和ApaI酶切分别获得33和45个PFGE带型。结论杭州地区单核细胞增生李斯特菌食品分离株分子型别分布广泛,大部分菌株是可引起人李斯特菌病的Lineage I和Lineage II菌株。食品中单核细胞增生李斯特菌的污染比较严重,应加强监测与管理以防食源性疾病的发生。     

Development of antistaphylococcal vaccines

Staphylococcus aureus is frequently isolated from both hospital-acquired and community-acquired infections, and the emergence of antibiotic resistance among clinical isolates has made treatment of staphylococcal infections difficult. This scenario has sparked renewed interest in the development of a vaccine for individuals at high risk for staphylococcal infections. As part of the effort to develop a multicomponent vaccine against S. aureus, several vaccine candidates are currently being evaluated in animal models of staphylococcal infection or in human clinical trials. The most promising candidates to date include adhesins (fibronectinbinding protein, collagen-binding protein, and fibrinogenbinding protein [clumping factor]), a nontoxic alpha toxin mutant, and capsular polysaccharides type 5 and 8.     

Methicillin-resistant Staphylococcus aureus: a new community-acquired pathogen?

PURPOSE OF REVIEW: The main goal of this review is to describe the emergence of methicillin-resistant Staphylococcus aureus (MRSA) as a community pathogen. RECENT FINDINGS: Community-acquired MRSA has emerged as an important infection in the community setting. It has primarily been associated with skin and soft-tissue infections, but can also cause severe pulmonary infections, including pneumonia and empyema. Community-acquired MRSA is typically more susceptible to a wider class of antibiotics than healthcare-associated MRSA. Community-acquired MRSA is also more virulent compared with healthcare-associated MRSA isolates. Community-acquired MRSA usually contains the gene encoding Panton-Valentive leukocidin, which is a toxin that creates lytic pores in the cell membranes of neutrophils and induces the release of neutrophil chemotactic factors that promote inflammation and tissue destruction. The optimal antibiotic treatment for Panton-Valentive leukocidin-positive community-acquired MRSA is unknown; however, antibiotics with activity against MRSA and the ability to inhibit toxin production may be optimal (linezolid or clindamycin for susceptible isolates). SUMMARY: Clinicians should be aware of the emergence of community-acquired MRSA as an important cause of serious infections arising in the community setting. Appropriate antibiotic therapy should be initiated as soon as infection with this pathogen is suspected.     

Emergence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infection in Queensland, Australia.

OBJECTIVES: To investigate the incidence and epidemiology of non-multiresistant methicillin-resistant Staphylococcus aureus (nmMRSA) infection in south-east Queensland, Australia. STUDY DESIGN: A retrospective survey was done of hospital records of all patients who had non-multiresistant MRSA isolated at Ipswich Hospital (a 250-bed general hospital, 40 km south-west of Brisbane, Queensland, Australia) between March 2000 and June 2001. Laboratory typing of these isolates was done with antibiogram, pulsed-field gel electrophoresis, bacteriophage typing and coagulase gene typing. RESULTS: There were 44 infections caused by nmMRSA. Seventeen infections (39%) occurred in patients from the south-west Pacific Islands (predominantly Samoa, Tonga and New Zealand). Laboratory typing showed that the isolates in Pacific Islanders were Pacific Island strains, and 16/17 of these infections were community acquired. Twenty-three infections (52%) occurred in Caucasians. Eleven of the isolates from Caucasians (48%) were a new predominantly community-acquired strain that we have termed the 'R' pulsotype, nine (39%) were Pacific Island strains, and three (13%) were health care institution-associated strains. Four infections occurred in patients who were not Caucasians or Pacific Islanders. Overall, 34 of all 44 infections (77%) were community acquired. Conclusions: Non-multiresistant MRSA infection, relatively frequently observed in Pacific Islanders in south-east Queensland, is now a risk for Caucasians as well, and is usually community acquired. Clinicians should consider taking microbiological specimens for culture and antimicrobial susceptibility testing in patients with suspected staphylococcal infections who are not responding to empirical therapy with beta-lactam antibiotics.     

Genotypic analysis of serogroups other than A, B or C of Neisseria meningitidis in China

To serologically and genetically characterize other serogroups (except A, B, and C) of Neisseria meningitidis isolates in China, we collected 56 strains of other serogroups, identified by serogroup typing and multilocus sequence typing (MLST). All of them are non-invasive isolates. The serogroups of the 56 Chinese isolates were W135 (11 isolates), Y (4), X (15), 29E (15), D (1), H (4), I (3), K (2), and non-groupable (1). By MLST, 34 different sequence types (STs) were identified, 28 of which were not found in the MLST database as of July 2006 and seemed to be unique to China. Statistical analysis of the MLST results revealed that, although the Chinese isolates seemed to be genetically divergent, they could be classified into 5 major clonal groups and other minor groups. Among these isolates, none of the well-documented ST complexes found worldwide was present.