1517株金黄色葡萄球菌的临床分布及药敏结果分析

目的了解金黄色葡萄球菌(Staphylococcus aureus,S.aureus)的分布及耐药率,为临床合理用药提供参考。方法对2008年1月至2013年12月从各类临床标本中分离的S.aureus进行统计分析。判断标准均按CLSI 2013年规定标准判定结果,以WHONET 5.6统计软件进行数据分析。结果共检出1 517株S.aureus,其中耐甲氧西林金黄色葡萄球菌(MRSA)669株,占44.1%;构成比居前的标本来源是皮肤分泌物(693株)、痰液(487株)及血液(70株),MRSA在其中检出率分别为30.9%、71.0%和37.0%,痰液来源中的MRSA分离率比其余两者高,差别有统计学意义(P<0.05);科室分布居前的有皮肤科(440株)、重症监护室(156株)、肿瘤科(118株)、耳鼻喉科(114株)及神经科(101株),MRSA检出率分别是27.7%、75.9%、40.4%、27.2%和69.1%,重症监护室及神经科检出的MRSA比例比其他三个科高,差异有统计学意义(P<0.05)。S.aureus对青霉素耐药严重,高达94.6%,对大环内酯类、四环素耐药率较高,均为50%以上,对喹诺酮类、庆大霉素为35%以下,对利福平及复方新诺明较敏感,未达到20%,未发现对万古霉素、利奈唑胺和替考拉宁耐药的S.aureus。结论 S.aureus感染的标本来源与分离科室不同,MRSA检出率有差别,耐药率有较大差异,临床医师应根据药敏结果选择使用抗菌药物。     

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.     

临床分离金黄色葡萄球菌药物敏感性及其生物膜形成能力的研究CSCD

目的 初步探讨临床分离金黄色葡萄球菌药物敏感性与其生物膜形成的关系。方法 收集2020年1月至2022年1月大同市第二人民医院检验科临床送检的痰液、尿液、血液和伤口分泌物等样本。采用VITEK-2全自动微生物菌株鉴定系统分离出非重复致病性金黄色葡萄球菌60株;采用刚果红试验定性鉴定产膜菌株和非产膜菌株;采用VITEK-2全自动微生物药敏试验系统进行药敏分析;采用96微孔板试验半定量鉴定菌株产膜能力。结果 通过VITEK-2全自动微生物菌株鉴定系统检出耐甲氧西林金黄色葡萄球菌(MRSA)32例(53.3%),甲氧西林敏感型金黄色葡萄球菌(MSSA)28例(46.7%)。生物膜阳性菌30株(50.0%),生物膜阴性菌30株(50.0%)。其中,MRSA菌株产膜率53.1%,MSSA菌株产膜率46.4%,二者差异无统计学意义(P>0.05)。96微孔板试验筛选出强产膜菌株7株(23.3%),弱产膜菌株23株(76.7%)。强产膜菌株中,MRSA菌株6株,占85.7%,耐药5种以上占71.4%;弱产膜菌株中,MRSA菌株11株,占47.8%,耐药5种以上占26.1%;30株生物膜阴性菌,耐药5种以上占26.7%。结论 本研究临床分离的金黄色葡萄球菌中,MRSA菌株产膜能力强于MSSA菌株,产膜菌株耐药种类高于非产膜菌株。     

耐甲氧西林金黄色葡萄球菌的耐药及其检测方法

耐甲氧西林金黄色葡萄球菌（MRSA）是引起医院感染的多重耐药菌,其有效的治疗药物为万古霉素。近年已发现对万古霉素耐受的金黄色葡萄球菌,金黄色葡萄球菌一旦对万古霉素耐药,临床将面临无药可供选择的局面。由于其所造成治疗上的困难,对其耐药机制的深入研究和该菌准确、及时的检出对于寻找新的治疗靶位和防止其播散有着极其重要的意义。本文就mecA耐药决定子、调节基因、染色体上的辅助基因对耐甲氧西林金黄色葡萄球菌耐药表达的影响及其表型和基因检测方法作一综述。     

金黄色葡萄球菌对甲氧西林耐药的分子机制

耐甲氧西林金黄色葡萄球菌是医院内和社区感染的重要现菌,所致感染治疗困难,因此成为各国学者关注与研究的热点。本文就近几年国内外在ＭＲＳＡ耐药分子机制的研究中取得的成果,如ｍｅｃＡ基因以及其他与ＭＲＳＡ对甲西林抗性表达相关基因的定位,结构及功能等作一介绍。     

社区获得性和医院获得性耐甲氧西林金黄色葡萄球菌PVL基因检测

目的 调查本地区患者各种标本中分离耐甲氧西林金黄色葡萄球菌(MRSA)的杀白细胞素(PVL)基因携带情况,为临床MRSA的治疗及流行病学调查提供合理的依据.方法 对所分离的MRSA菌株进行药敏试验分析,同时采用PCR法检测mecA基因和PVL基因,比较社区获得性MRSA (CA-MRSA)和医院获得性MRSA (HA-MRSA)之间耐药性的比较及PVL基因携带率的比较.结果 对不同来源的9l株MRSA分离株耐药性分析,CA-MRSA对环丙沙星、利福平、庆大霉素和左旋氧氟沙星的敏感性明显高于HA-MRSA.经PCR检测发现,所有菌株均携带有mecA基因,21株携带有PVL基因,其中65株HA-MRSA有仅8株携带有PVL基因,而26株CA-MRSA中有13株携带有PVL基因,携带率差异有统计学意义.结论 本地区CA-MRSA是携带PVL基因的主要菌株,HA-MRSA对抗菌药物的耐药性明显高于CA-MRSA,尚未发现对万古霉素和替考拉宁的耐药菌株.     

携带杀白细胞素基因金黄色葡萄球菌的研究进展

杀白细胞素(Panton-Valentine leukocidin,PVL)是金葡菌产生的重要外毒素之一,PVL在其感染所致的坏死性皮肤损害和坏死性肺炎等疾病中起重要作用,并且能在社区和医院传播。现在国内外对PVL阳性金葡菌的研究日益重视,本文就其感染的致病机制、感染状况、检测方法和防治措施等问题研究作一陈述。     

74例金黄色葡萄球菌乳腺炎的耐药性分析

目的分析哺乳期乳房脓肿患者的金黄色葡萄球菌的耐药情况,指导临床合理使用抗菌药物。方法将厦门市妇幼保健院乳腺门诊及病房2009年2月至2011年1月抽取的128例哺乳期乳房脓肿患者的乳腺脓液接种于哥伦比亚血平板,置35℃培养箱,过夜孵育18~24 h。革兰阳性球菌,触酶阳性,血浆凝固酶试验(+),必要时采用ATB-Expression细菌鉴定系统确认。用K-B纸片法检测其对苯唑西林等10种抗菌药物的敏感度。结果 128例检出细菌86例,阳性率67.2%,其中检出74株金黄色葡萄球菌(86.0%),其对青霉素、红霉素和克林霉素有较强的耐药性,耐药率分别为94.6%、64.9%和59.5%;耐苯唑西林19株(25.7%),对复方新诺明、磷霉素和庆大霉素较为敏感,对万古霉素、替考拉宁和左旋氧氟沙星100%敏感。结论哺乳期乳房脓肿致病菌主要为金黄色葡萄球菌,耐甲氧西林金黄色葡萄球菌(MRSA)占25.7%,其耐药情况不容忽视,青霉素类、大环内酯类等耐药率较高不能作为经验用药。建议临床使用抗菌药物前及时送检乳腺脓液细菌培养,以药敏结果指导临床合理经济用药。     

Cloning and sequencing of the gene, fmtC, which affects oxacillin resistance in methicillin-resistant Staphylococcus aureus

Two Tn551 insertional mutants with reduced methicillin resistance were isolated from methicillin-resistant Staphylococcus aureus KSA8. These two mutants showed increased susceptibility to beta-lactam antibiotics and bacitracin, but not to fosfomycin and vancomycin. Tn551 in these mutants was inserted into the same gene, termed fmtC. The fmtC gene has an open reading frame of 840 amino acid residues with an estimated molecular mass of 96.9 kDa. The N-terminal half of the deduced FmtC protein is very hydrophobic, implying that this protein is a membrane-associated protein.     

Lead resistance and sensitivity in Staphylococcus aureus

Abstract Five lead-resistant strains of Staphylococcus aureus were isolated. Plasmid-free lead-sensitive variants were obtained from the three plasmid-bearing strains. Lead-resistant strains tolerated an approximately 600 × higher Pb(NO₃)₂ concentration than lead-sensitive strains. Both types of strains initially bound lead, but only the resistant strains accumulated the metal as an intracellular lead-phosphate.     

Conjugative trimethoprim resistance in Staphylococcus aureus

A multiply resistant Staphylococcus aureus isolate, WBG7410, harbours plasmids of 38, 26, 2.8, 2.4 and 1.9 kb and transfers trimethoprim and kanamycin resistance at high frequencies by conjugation. The transconjugants contained the 38-kb plasmid, pWBG707, and the 2.8-kb plasmid. Plasmid pWBG707 was shown to encode trimethoprim resistance, was conjugative and mobilised at high frequencies the 2.8-kb plasmid which presumably encodes kanamycin resistance. Plasmid pWBG707 was isolated mostly in the open circular form and analysis with EcoRI restriction endonuclease suggests that pWBG707 is a new conjugative plasmid distinct from the other conjugative plasmids reported in S. aureus.     

治疗耐甲氧西林金黄色葡萄球菌感染的抗体药物

耐甲氧西林金黄色葡萄球菌(methicillin-resistant staphylococcus aureus, MRSA) 作为超级细菌的典型代表,严重威胁人民群众的健康。目前经典的抗生素治疗和疫苗主动预防都无法有效控制MRSA的感染。近年来,随着抗体药物产业的兴起,诸多药物研发公司和研究人员致力于研究治疗性抗体,以期控制MRSA的感染并已经取得了很多突破。就治疗MRSA感染的抗体药物研究进展作一简要综述。     

Novel arbekacin- and amikacin-modifying enzyme of methicillin-resistant Staphylococcus aureus

An aminoglycoside-modifying enzyme in arbekacin-resistant methicillin-resistant Staphylococcus aureus (MRSA), exhibiting 4'-N-acetylation, was examined. Although the MRSA strain with AAC(4') had no AAC(6')-APH(2") activity, a DNA fragment of the AAC(6')-APH(2") gene was amplified by PCR and the purified N-terminal 30-amino acid sequence of this AAC(4') was identical to AAC(6')-APH(2"). Direct DNA sequencing of this 'silent' AAC(6')-APH(2") gene revealed a single point mutation leading to a substitution of Gly for Asp80, through which the secondary structure is affected. A change in protein conformation could lead to a cleavage and a change of the enzymatic activity. We propose a new aminoglycoside-resistance mediated by AAC(4') is caused by a mutation-modified AAC(6')-APH(2").     

Triton X-100-induced lipoteichoic acid release is correlated with the methicillin resistance in Staphylococcus aureus

We previously reported that Triton X-100 (TRX) reduced methicillin resistance in Staphylococcus aureus, although the degree of reduction varied among strains. One of the biological effects of TRX on S. aureus cells was enhancement of lipoteichoic acid (LTA) release. We investigated the correlation between the amount of LTA released and the degree of reduction in methicillin resistance induced by TRX. The strains showing the greatest reduction of methicillin resistance released the largest amount of LTA, compared to those showing slight or moderate reduction. A mutant whose resistance was not affected by TRX did not increase its release of LTA. These findings suggest that LTA release is associated with a reduction in methicillin resistance in the presence of TRX.     

Identification of a fmtA-like gene that has similarity to other PBPs and beta-lactamases in Staphylococcus aureus

We identified a gene from Staphylococcus aureus, flp (fmtA-like protein), encoding a protein of 489 amino acid residues with a molecular mass of 56.4 kDa. The deduced amino acid sequence shows similarity to previously characterized penicillin binding proteins (PBPs) and FmtA of S. aureus (one of the factors which affect methicillin resistance). FLP protein has three motifs, which are conserved in PBPs and beta-lactamases, suggesting that it might be associated with cell wall synthesis. Recombinant FLP protein, however, lacks penicillin binding activity, and the inactivation of flp in two methicillin-resistant S. aureus strains did not cause a reduction in the methicillin resistance.     

Effects of sarA inactivation on the intrinsic multidrug resistance mechanism of Staphylococcus aureus

The sarA locus of Staphylococccus aureus regulates the synthesis of over 100 genes on the S. aureus chromosome. We now report the effects of sarA inactivation on intrinsic multidrug resistance expression by S. aureus. In a strain-dependent fashion, sarA::kan mutants of three unrelated strains of S. aureus demonstrated significantly increased susceptibility to five or more of the following substances: the antibiotics ciprofloxacin, fusidic acid, and vancomycin; the DNA-intercalating agent ethidium; and four common household cleaner formulations. In addition, all three sarA::kan mutants demonstrated significantly increased accumulation of ciprofloxacin and one sarA::kan mutant demonstrated increased ethidium accumulation. Our data therefore indicate that sarA plays a role in the intrinsic multidrug resistance mechanism expressed by S. aureus, in part by regulating drug accumulation.