耐甲氧西林金黄色葡萄球菌SCCmec分型研究

摘要： 目的 分析本地区分离的耐甲氧西林金黄色葡萄球菌（MRSA）葡萄球菌盒染色体mec（SCCmec）类型。 方法 利用3套多重PCR体系扩增耐甲氧西林金黄色葡萄球菌SCCmec型特异性位点、共同位点、鉴别位点、内参照位点以及mec基因复合物和ccr基因复合物进行SCCmec分型。 结果 分离的156株MRSA中,6株MRSA不能分型,可分型率为96.2%。其中,Ⅲ型SCCmec 125株,占83.3%,Ⅱ型SCCmec 11株,占7.3%,Ⅳ、Ⅴ型SCCmec 各7株,占4.7%。 结论 本地区分离的耐甲氧西林金黄色葡萄球菌流行携带最多耐药基因的Ⅲ型SCCmec。     

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。     

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...     

耐甲氧西林金黄色葡萄球菌MLVA分型研究

目的对部分2000~2005年北京分离株耐甲氧西林金黄色葡萄球菌(MRSA)进行多位点串联重复序列分析(MLVA),为探索易行的分型方法提供依据。方法对49株MRSA进行MLVA分型,并与PFGE分型结果进行比较,观察MLVA方法的分型效率和特征。结果49株MRSA在分析时的MLVA分辨系数为0.820,共产生12种条带类型,C、G、I为主要型别,分别占24.49%(12/49)、18.37%(9/49)和30.61%(15/49)。MLVA方法与PFGE方法cutoff值分别为80%与85%时的符合率为93.87%,cutoff值分别为90%与89%时的符合率有所下降。结论ML-VA方法具有较高的分型效率,与PFGE方法有较好的符合率,该方法在MRSA流行株初筛研究中具有推广价值。     

36株临床分离耐甲氧西林金黄色葡萄球菌的SCCmec基因分型及耐药性分析

目的探究临床分离耐甲氧西林金黄色葡萄球菌的SCCmec基因分型和耐药性。方法将选取的36株耐甲氧西林金黄色葡萄球菌采取多重PCR的方法进行SCCmec基因分型,并采取K-B纸片扩散法进行耐药性的分析。结果通过检测分析,SCCmecⅡ型菌株有2株(5.6%),SCCmecⅢ型菌株有30株(83.3%),SCCmecⅣ型菌株有4株(11.1%)。并且SCCmecⅡ型和SCCmecⅢ型的菌株均数均具有较高的耐药性。结论分离耐甲氧西林金黄色葡萄球菌的SCCmec的基因分型表现为SCC-mecⅡ型和SCCmecⅢ型以及SCCmecⅣ型菌株,其中SCCmecⅡ型和SCCmecⅢ型均表现为多重的耐药性。     

养殖源耐甲氧西林金黄色葡萄球菌的SCCmec耐药元件、毒力危害和流行性分析

金黄色葡萄球菌(Staphylococcus aureus)是一种常见的人兽共患病病原菌,其分泌的外毒素如溶血素、杀白细胞素、脱皮毒素、肠毒素等可引发人或养殖动物多种疾病。耐甲氧西林金黄色葡萄球菌(Methicillin-resistant Staphylococcus aureus, MRSA)是携带含mec基因簇的葡萄球菌盒氏染色体(Staphylococcal chromosome cassette mec, SCCmec)遗传元件的多重耐药菌。SCCmec对MRSA的多重耐药性起重要作用。SCCmec元件中mecA基因介导了MRSA对β-内酰胺类药物的耐药性,而SCCmec元件的可变区插入的耐药基因对MRSA的多重耐药性具有重要作用。近年来,欧洲、北美等国家陆续报道在养殖业环境及动物中检测到多重耐药的养殖源MRSA(Livestock-associated MRSA,LA-MRSA),且LA-MRSA可以通过养殖环境等途径传播到人,对人的健康和公共卫生安全构成潜在威胁。本文综述了S. aureus的耐药性变化、MRSA的SCCmec耐药元件和SCCmec型别变迁以及LA-MRSA的毒力危害和流行状况,对了解S. aureus耐药性和SCCmec分型以及控制和预防LA-MRSA在人兽间传播、感染具有一定的指导意义。     

非放射性DNA探针检测金黄色葡萄球菌耐甲氧西林基因

非放射性ＤＮＡ探针检测金黄色葡萄球菌耐甲氧西林基因莫岚王其南作者单位：４３００４２重庆医科大学附属第一医院用常规的药敏试验检测耐甲氧西林金黄色葡萄球菌（金葡菌，ＭＲ－ＳＡ），耗时较长，且结果不够准确。由于只有ＭＲＳＡ才含有ｍｅｃＡ基因，而甲氧西林敏感...     

临床分离耐甲氧西林金黄色葡萄球菌染色体mec盒基因的分型

目的分析我国临床分离的耐甲氧西林金黄色葡萄球菌（MRSA）葡萄球菌染色体mec盒（SCCmec）基因型。方法来源于全国17家医院分离的金黄色葡萄球菌共计266株，采用琼脂对倍稀释法测定23种抗菌药物最低抑菌浓度（MIC），并利用多重PCR方法对MRSA菌株进行SCCmec、基因分型。结果266株金黄色葡萄球菌对多种抗生素呈现不同程度的耐药，其中MRSA160株，占临床分离菌株的60．2％，PCR方法分型获得SCCmecⅡ型1株，占0．6％、Ⅱ型的亚型4株，占2．5％、Ⅲ型20株，占12．5％、含有342bp（dcs）额外扩增条带的Ⅲ型菌株108株，占67．5％、ⅢA型11株，占6．9％、16株细菌未能分型，占10％，未发现Ⅰ型和Ⅳ型。结论我国l临床分离的MRSA以SCCmec，Ⅲ-dcs型为主，该类型为多重耐药菌株，基因组成与SCCmecⅢ型及ⅢA型有差异。     

A nosocomial outbreak of community-associated methicillin-resistant Staphylococcus aureus among healthy newborns and postpartum mothers

BACKGROUND: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has increasingly been isolated from individuals with no predisposing risk factors; however, such strains have rarely been linked to outbreaks in the hospital setting. The present study describes the investigation of an outbreak of CA-MRSA that occurred in the maternal-newborn unit of a large community teaching hospital in Toronto, Ontario. METHODS: Screening and clinical specimens collected from mothers and newborns delivered during the outbreak period, as well as from staff on the affected unit, were submitted for microbiological testing. Computerized delivery logs and nursing notes were reviewed, and a case control study was conducted. RESULTS: Analysis by pulsed-field gel electrophoresis revealed 38 babies and seven mothers with MRSA colonization and/or infection by the same unique strain (Canadian MRSA-10-related) from September to December 2004. Isolates were characterized as having the staphylococcal chromosome cassette mec type IVa and were positive for the Panton-Valentine leukocidin gene. No one health care worker was associated with all cases; however, mothers and newborns exposed to one particular nurse (Nurse A) were almost 23 times (odds ratio 22.7, 95% CI 3.3 to 195.9) more likely to acquire MRSA than those with no such contact. MRSA was successfully isolated from Nurse A and from an environmental swab of a telephone recently used by Nurse A; both isolates matched the pulsed-field gel electrophoresis pattern of the outbreak strain. CONCLUSION: The first nosocomial outbreak of CA-MRSA among healthy newborns and postpartum mothers in Canada is described. Effective control of sustained MRSA transmission within an institution may require prompt identification, treatment and monitoring of colonized and/or infected staff.     

江苏地区金黄色葡萄球菌耐药及分子分型研究

目的 研究江苏省不同地区金葡菌的耐药性、耐药基因和分子分型的特征联系。方法 收集2017年全省各市哨点医院金黄色葡萄球菌227株,采用微量肉汤稀释法测定15种抗生素最小抑菌浓度, PCR方法检测7种不同的耐药基因,并用多位点序列分型(multilocus sequence typing MLST)进行分子分型。结果 本研究中金葡菌对青霉素、红霉素、头孢西丁、苯唑西林、克林霉素、左氧氟沙星、四环素、庆大霉素的耐药率较高,而对替考拉宁、利福平、复方新诺明、达托霉素、利奈唑胺以及呋喃妥因多呈敏感,耐药率均低于10%,且所有菌株均对万古霉素敏感。共计检出117株MRSA,MRSA平均耐药种数和平均耐药基因携带数高于MSSA(P< 0.05)。江苏省苏北地区的菌株耐药种数要高于苏中和苏南地区(P< 0.05),而苏中地区的耐药基因平均携带数高于苏南地区(P< 0.05)。在227株金葡菌中发现了60个ST型,以ST59和ST398分布数量最多,并有29个新ST型。成簇菌株中,CC59的平均耐药种数和MRSA检出率均高于其他克隆群。结论 江苏省内不同地区的金葡菌耐药率和耐药机制存在差异,且以CC59克隆群耐药情况最为严峻。     

Characterization of methicillin-resistant Staphylococcus aureus isolates from patients with persistent or recurrent bacteremia

BACKGROUND:

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are associated with considerable morbidity and mortality, especially with persistent (PB) or recurrent bacteremia (RB).

OBJECTIVE:

To determine the frequency of PB and RB in patients with MRSA BSI, and to characterize the isolates from these patients.

METHODS:

Surveillance for MRSA BSI was performed for one year in 13 Canadian hospitals. PB was defined as a positive blood culture that persisted for ≥7 days; RB was defined as the recurrence of a positive blood culture ≥14 days following a negative culture. Isolates were typed using pulsed-field gel electrophoresis (PFGE). Vancomycin susceptibility was determined using Etest.

RESULTS:

A total of 183 patients with MRSA BSI were identified; 14 (7.7%) had PB and five (2.7%) had RB. Ten (5.5%) patients were known to have infective endocarditis, and five of these patients had PB or RB. Initial and subsequent MRSA isolates from patients with PB and RB had the same PFGE type. There were no significant differences in the distribution of PFGE types in patients with PB or RB (37% CMRSA-2/USA100; 37% CMRSA-10/USA300) compared with that in other patients (56% CMRSA-2/USA100; 32% CMRSA-10/USA300). All isolates were susceptible to vancomycin, but patients with PB or RB were more likely to have initial isolates with vancomycin minimum inhibitory concentration = 2.0 μg/mL (26% versus 10%; P=0.06).

CONCLUSIONS:

Persistent or recurrent MRSA bacteremia occurred in 10.4% of patients with MRSA BSIs. Initial isolates from patients with persistent or recurrent MRSA BSIs were more likely to exhibit reduced susceptibility to vancomcyin, but were not associated with any genotype.     

In vitro susceptibility of methicillin-resistant Staphylococcus aureus isolates from skin and soft tissue infections to vancomycin,daptomycin, linezolid and tedizolid

Introduction

Treatment of multidrug-resistant Gram-positive infections caused by Staphylococcus aureus remains as a clinical challenge due to emergence of new resistance mechanisms. Tedizolid is a next-generation oxazolidinone, recently approved for skin and soft tissues infections. We conducted a study to determine in vitro susceptibility to vancomycin, daptomycin, linezolid and tedizolid in MRSA clinical isolates from adult patients with skin and soft tissue infections.

Control of methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of nosocomial infections worldwide. Different approaches to the control of this pathogen have met with varying degrees of success in different health care settings. Controversies exist with regards to various MRSA control strategies. The implementation and outcomes of control measures depend on several factors, including scientific, economic, administrative, governmental, and political influences. It is clear that flexibility to adapt and institute these measures in the context of local epidemiology and resources is required.