青蒿琥酯对痤疮丙酸杆菌的体外抑菌作用及机制研究

目的探究青蒿琥酯对痤疮丙酸杆菌的体外抑菌作用及相关机制。方法采用微量肉汤稀释法检测痤疮丙酸杆菌标准株和临床株,观测青蒿琥酯联合盐酸多西环素的最小抑菌浓度(MIC),并观察2种药物对痤疮丙酸杆菌生长的动态影响。采用扫描电镜观察青蒿琥酯作用后痤疮丙酸杆菌的形态学变化。结果青蒿琥酯MIC为0.750~3.000 mg/mL,盐酸多西环素MIC为0.040~0.160μg/mL,两药联合使用呈相加或协同抑菌作用。两药在单药和联合使用时的MIC差异有统计学意义(P<0.05)。细菌生长动态观察结果显示两药联合使用可降低药物浓度,且抑菌作用起效快、持续时间长。扫描电镜观察结果显示青蒿琥酯作用后菌体变短,表面有皱瘪、凹陷、弯折等改变。结论青蒿琥酯对痤疮丙酸杆菌有一定抑菌作用,与盐酸多西环素联合使用抑菌效果优于单独使用,且对痤疮丙酸杆菌形态有影响。     

烧伤方剂对金黄色葡萄球菌的体外抑制实验研究

目的 探讨烧伤方剂对金黄色葡萄球菌体外的抑菌作用.方法 采用打孔法和稀释法检测烧伤方剂和万古霉素对金黄色葡萄球菌(SA)的抑菌圈和最小抑菌浓度(MIC).结果 烧伤方剂和万古霉素对金黄色葡萄球菌的抑菌圈直径分别为21.0 mm和22.3,MIC分别为28.2 mg/mL和32.0 μg/mL.结论 烧伤方对金黄色葡萄球菌有较强的抑制作用,具有较高的临床应用价值.     

芦荟苷对金黄色葡萄球菌生长抑制作用及对溶血毒素表达的影响

目的研究芦荟苷体外对金黄色葡萄球菌生长抑制作用以及对溶血素表达的影响。方法采用肉汤倍比稀释法检测芦荟苷水溶物对金黄色葡萄球菌最低抑菌浓度(MIC);琼脂打孔法观察芦荟苷对金黄色葡萄球菌的抑菌圈大小;试管法检测芦荟苷作用下金黄色葡萄球菌凝固酶的产生变化;检测芦荟苷作用下金黄色葡萄球菌溶血素活性变化;采用实时荧光定量PCR检测芦荟苷水溶物作用于金黄色葡萄球菌后对hla和agr A基因表达的影响。结果芦荟苷水溶物可抑制金黄色葡萄球菌生长并呈现浓度依赖性,作用于ATCC 25923和临床菌株SA1.5后的抑菌圈直径和MIC分别为21.5 mm、12.5 mg/m L和17mm、15 mg/m L;与对照组凝固酶效价32比较,1/2MIC组、MIC和2MIC组芦荟苷作用ATCC 25923后的凝固酶效价分别降为16、4和2;与对照组相比,1/2MIC组、MIC组及2MIC组芦荟苷水溶物降低ATCC 25923溶血活性,溶血率分别为(77.4±3.41)%、(42.2±2.4)%和(38.7±2.4)%;1/2MIC组、MIC组和2MIC组芦荟苷作用ATCC 25923后hla表达量分别为0.020 3(0.019 6,0.028 8)、0.011 6(0.010 6,0.013 1)和0.033 7(0.020 2,0.042 9),3组间差异有统计学意义(H=16.807,P0.05);agr A表达量分别为0.074 6(0.066 2,0.098 2)、0.020 8(0.012 2,0.032 6)和0.021 3(0.010 2,0.029 6),3组间差异有统计学意义(H=16.320,P0.05)。结论芦荟苷可抑制金黄色葡萄球菌生长,并对α-溶血素表达有抑制作用。     

什么是VISA?

问:什么是VISA? 答:VISA是英文vancomycin intermediate S.aureus的缩写,中文译为万古霉素中度耐药金黄色葡萄球菌.细菌对万古霉素敏感度的判断标准,美国临床实验室标准化委员北会的规定是最低抑菌浓度(MIC)≤4 μg/ml为敏感,MIC≥32 μg/ml为耐药,MIC=8～16 μg/ml为中度耐药.所以,将万古霉素MIC在8～16 μg/ml的金黄色葡萄球菌称为VISA.VISA名称的产生源于1996年和1997年分别在日本和美国发现的万古霉素MIC=8 μg/ml的耐甲氧苯西林金黄色葡萄球菌.这种菌株没有万古霉素耐药基因,不表现高度耐药(MIC＞32 μg/ml).VISA的发现提示万古霉素高度耐药葡萄球菌可能会出现.检测VISA,实验室须做稀释法药敏试验,纸片扩散法可能会漏检.     

复方三黄液对60株骨科分离金黄色葡萄球菌体外抑菌效果研究

目的：了解复方三黄液对金黄色葡萄球菌的体外抑菌效果,为临床应用提供实验室依据。方法采用肉汤稀释法,以复方三黄液为抑菌药,观察其对骨科感染分离出的60株金黄色葡萄球菌的最小抑菌浓度（MIC）和最小杀菌浓度（MBC）。结果42株 MSSA 中32株 MIC 为7．8μg/mL,10株 MIC 为15．6μg/mL;18株 MRSA 中14株 MIC 为7．8μg/mL,4株 MIC为15．6μg/mL。MRSA 组均值为9．6μg/mL,MSSA 均值为9．5μg/mL。结论复方三黄液对金黄色葡萄球菌体外抑菌效果明显,并能避免耐药菌的产生。     

土槿乙酸体外抗(抑)菌作用的研究

目的观察土槿乙酸对常见致病菌体外抑制效果,为实际应用研究提供依据。方法采用微量稀释法进行了实验室试验和皮肤抗菌试验。结果土槿乙酸溶液对大肠杆菌和福志贺杆菌MIC值为0.5 g/L,对奇异变形杆菌和表皮葡萄球菌的MIC值为1.0 g/L,对金黄色葡萄球菌的MIC值为2.0 g/L。用2.0 g/L土槿乙酸溶液涂擦人体前臂皮肤作用2 min,可使皮肤上自然菌由处理前的226 cfu/cm2降低到11 cfu/cm2。结论土槿乙酸对细菌繁殖体有明显抑菌作用,金黄色葡萄球菌对其抗力比其他细菌繁殖体强。     

复方牛苓颗粒体外抑菌实验研究

目的:观察复方牛苓颗粒体外对大肠杆菌、金黄色葡萄球菌、解脲支原体的体外抑制作用.方法:将阳性药复方牛苓颗粒和对照药前列安通片分别制成药液,连续2倍比稀释,观察2组药对大肠杆菌、金黄色葡萄球菌、解脲支原体的体外抑制情况.结果:复方牛苓颗粒对大肠杆菌的抑菌作用,MIC50为50mg/ml、MIC90为50mg/ml,对解脲支原体抑制作用,MIC50为0.78mg/ml、MIC90为3.12mg/ml;前列安通片对大肠杆菌的抑制作用,MIC50为50mg/ml、MIC90为200mg/ml,对解脲支原体抑制作用,MIC50、MIC90都为6.25mg/ml;2组药对金黄色葡萄球菌的抑菌作用,MIC50、MIC90都为6.25mg/ml.结论:复方牛苓颗粒对金黄色葡萄球菌、大肠杆菌、解脲支原体有一定的抑制作用.     

异质性万古霉素中介金黄色葡萄球菌的分离及检测方法的建立

目的 了解异质性万古霉素中介金黄色葡萄球菌(h-VISA)的分离情况,并筛选简便可行的h-VISA的检测方法.方法 采用琼脂稀释法和E-test法对分离出的113株金黄色葡萄球菌进行检测,筛选出的可疑h-VISA用菌谱分析法进行确认,并对文献推荐的几种方法的筛选效果进行比较.结果 检测到1株万古霉素的MIC为3 μg/mL和2株MIC为4 μg/mL的MRSA,为万古霉素敏感性减低的金黄色葡萄球菌,其中1株MIC为4 μg/mL的MRSA经菌谱分析法证实为h-VISA,本次113株实验菌株h-VISA的检出率为0.88%.结论 通过实验证实K-B法并不是检测h-VISA的理想方法,而菌谱分析法则较为有效,分离率为8.3%,且在本实验中灵敏度可达10-8.本院分离的MRSA中已出现万古霉素敏感性减低菌株,并分离出1株h-VISA,可见,MRSA对万古霉素的异质性中介耐药不容忽视,应引起国内医学界的广泛重视.     

特地唑胺对利奈唑胺不敏感革兰阳性球菌的体外抗菌活性研究

摘要:目的检测利奈唑胺不敏感革兰阳性球菌对新型噫唑烷酮类抗菌药物特地唑胺的敏感性，并探讨特地唑胺不敏感菌株 的耐药机制。方法收集临床分离非重复革兰阳性球菌 170株,包括利奈唑胺耐药头状葡萄球菌46株、利奈唑胺敏感头状葡 萄球菌19株、利奈唑胺不敏感肠球菌55株、利奈唑胺敏感肠球菌12株、甲氧西林耐药金黄色葡萄球菌19株、甲氧西林敏感 金黄色葡萄球菌18株、利奈唑胺耐药金黄色葡萄球菌1株。采用微量肉汤稀释法检测所有菌株对特地唑胺和利奈唑胺的最 小抑茵浓度(MIC),并比较两种药物的抗菌活性。采用PCR结合Sanger测序技术分析特地唑胺不敏感革兰阳性球茵fr、optrA 基因携带情况及23S rRNA V区突变。结果利奈唑胺耐药头状葡萄球茵(MICg0>256 μg/mL)对特地唑胺的MIC 值为4~ 32 ug/mL; 利奈唑胺不敏感肠球菌(MIC值4~ 16 μg/mL)中,特地唑胺的敏感率为10.% ,其MIC值为0.5~2 μg/mL;1株利奈 唑胺耐药金黄色葡萄球菌对特地唑胺敏感，MIC值为0.5μg/mL。特地唑胺对利奈唑胺敏感的金黄色葡萄球茵和肠球茵的 MIC值均为0.5 μg/mL,对利奈唑胺敏感头状葡萄球菌的MIC值为0. 125 μg/mL。耐药基因分析显示，特地唑胺耐药头状葡萄 球菌gfr基因携带率为87.0%(40/46) ,23S rRNA V区G2576T的突变率为100% ;特地唑胺不敏感肠球菌optrA 基因携带率为 85.7% (42/49) ,显著高于特地唑胺敏感株的22.2%( P<0.001);1株利奈唑胺耐药特地唑胺敏感的金黄色葡萄球菌携帶cfr基 因。结论对于利奈唑胺不敏感的革兰阳性球菌,特地唑胺的抗茵活性是利奈唑胺的8~32倍,其耐药机制可能与携带optrA 基因及23S rRNA V区G2576T突变有关。     

万古霉素及利奈唑胺对体内不同部位金黄色葡萄球菌感染的抑菌效果研究

[目的]比较万古霉素及利奈唑胺在体内不同部位金黄色葡萄球菌（SA）感染取样的最小抑菌浓度（MIC）及抑菌效果.[方法]检测万古霉素和利奈唑胺对115株不同部位（痰、血及伤口渗出液）分离出的SA包括耐甲氧西林金黄色葡萄球菌（MRSA）的MIC值.[结果]MRSA检出率为64.3%.万古霉素及利奈唑胺对所有SA敏感.万古霉素在痰、血及伤口渗出液中的SA的MIC ≤0.5 μg/mL的比例分别为77.8%、51.5%及40.5%.利奈唑胺在痰、血及伤口渗出液中的SAMIC ≤2 μg/mL的比例分别为82.2%、87.9%及91.9%.[结论]万古霉素在治疗呼吸道SA感染较血行及皮肤软组织SA感染的效果好,利奈唑胺组在治疗皮肤软组织SA感染优于呼吸道及血行SA感染,在皮肤软组织SA感染中利奈唑胺可作为临床的首选.     

In vitro activity of ceftobiprole against frequently encountered aerobic and facultative Gram-positive and Gram-negative bacterial pathogens: results of the CANWARD 2007-2009 study

The in vitro activity of ceftobiprole was evaluated against 15 011 clinical isolates obtained from patients in Canadian hospitals between 2007 and 2009. All Staphylococcus aureus were susceptible to ceftobiprole (MIC(90)'s for methicillin-susceptible Staphylococcus aureus and methicillin-resistant Staphylococcus aureus of ≤ 1 μg/mL and 2 μg/mL, respectively). Ceftobiprole was active against penicillin-susceptible Streptococcus pneumoniae (MIC(90), ≤ 0.06 μg/mL), penicillin-resistant Streptococcus pneumoniae (MIC(90), 0.5 μg/mL), Streptococcus pyogenes (MIC(90), ≤ 0.06 μg/mL), Staphylococcus epidermidis (MIC(90), ≤ 1 μg/mL), and Enterococcus faecalis (MIC(90), ≤ 1 μg/mL). Over 90% of Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Citrobacter freundii, Proteus mirabilis, and Serratia marcescens isolates were inhibited by a ceftobiprole concentration of ≤ 1 μg/mL. Ceftobiprole was not active against extended-spectrum β-lactamase-producing Escherichia coli and K. pneumoniae. The in vitro activity of ceftobiprole versus Pseudomonas aeruginosa was similar to that of cefepime (MIC(90), 16 μg/mL). The broad spectrum of activity by ceftobiprole would support further study of this agent in the treatment of hospital-acquired infections.     

In vitro activity of telavancin and comparator antimicrobial agents against a panel of genetically defined staphylococci

The in vitro activity of telavancin was determined for 94 diverse Staphylococcus spp. Telavancin had MIC(90) values of 0.5 μg/mL for methicillin-susceptible, methicillin-resistant, and vancomycin-susceptible Staphylococcus aureus, and coagulase-negative staphylococci isolates. Telavancin MICs were 0.5-1 μg/mL for vancomycin-intermediate S. aureus isolates and 2-4 μg/mL for vancomycin-resistant S. aureus strains.     

In vitro activity of dalbavancin and telavancin against staphylococci and streptococci isolated from patients in Canadian hospitals: results of the CANWARD 2007-2009 study

Two novel lipoglycopeptides, dalbavancin and telavancin, and relevant comparative agents were tested for in vitro activity against clinical isolates of staphylococci and streptococci collected in the cross-Canada surveillance study, CANWARD, in 2007-2009. The rank order of potency (based on MIC(90) [μg/mL], i.e., the concentration of antimicrobial agent required to inhibit the growth of 90% of isolates tested) of glycopeptides against both Staphylococcus aureus and Staphylococcus epidermidis was dalbavancin (0.06 μg/mL) >telavancin (0.5 μg/mL) > vancomycin (1-2 μg/mL); concurrent susceptibility or resistance to oxacillin in staphylococci did not affect potency of glycopeptides. Dalbavancin and telavancin also demonstrated potent activity against Streptococcus pneumoniae, including penicillin-resistant isolates (MIC(90), ≤ 0.03 μg/mL; ≤ 0.06 μg/mL), and Streptococcus pyogenes (≤ 0.03 μg/mL; 0.06 μg/mL). Based on their robust in vitro activities, dalbavancin and telavancin have the potential to treat Gram-positive infections caused by methicillin-resistant Staphylococcus aureus and penicillin-resistant Streptococcus pneumoniae.     

战创伤涂膜剂对常见化脓菌的抗菌活性研究

目的测定战创伤涂膜剂对常见化脓菌的最低抑菌浓度（minimum inhibitory concentration,MIC）和最低杀菌浓度（minimum bactericidal concentration,MBC）。方法以培养基稀释战创伤涂膜剂、氯己定甲硝唑乳膏至不同浓度,分别加入化脓菌标准菌株大肠埃希菌、金黄色葡萄球菌、铜绿假单胞菌、奇异变形杆菌悬液,菌液浓度为10^5cfu／ml,培养后观察细菌生长情况,确定两药的MIC和MBC并进行比较。结果战创伤涂膜剂对大肠埃希菌、金黄色葡萄球菌、铜绿假单胞菌、奇异变形杆菌的MIC分别为0．0625μg／ml、2μg／ml、4μg／ml、8μg／ml,MBC分别为0．125μg／ml、4μg／ml、4μg／ml、8μg／ml。氯己定甲硝唑乳膏对大肠埃希菌、金黄色葡萄球菌、铜绿假单胞菌、奇异变形杆菌的MIC分别为1μg／ml、8μg／ml、〉32μg／ml、〉32μg／ml,MBC分别为2μg／ml、16μg／ml、〉32μg／ml、〉32μg／ml。两药对金黄色葡萄球菌的杀菌率均达到99％以上。结论战创伤涂膜剂对常见化脓菌有良好的抑菌、杀菌作用。     

Surveillance of JNJ-Q2 activity tested against Staphylococcus aureus and beta-hemolytic streptococci as a component of the 2010 SENTRY Antimicrobial Surveillance Program

JNJ-Q2 is a novel broad-spectrum bactericidal fluorinated 4-quinolone with potent activity against Gram-positive and -negative pathogens with a balanced potency against both DNA gyrase and topoisomerase IV targets. JNJ-Q2 is in clinical development for the treatment of acute bacterial skin and skin-structure infections (ABSSSIs) and community-acquired bacterial pneumonia. With the use of reference broth microdilution methods in a central reference laboratory design, MIC values were obtained for 3650 pathogens (44.4% were from patients diagnosed with ABSSSI) obtained during the 2010 SENTRY antimicrobial surveillance program. Isolates were collected from patients in 96 medical centers in 26 countries in North America, Europe, Latin America, and Asia Pacific. JNJ-Q2 demonstrated good activity overall (MIC(50/90), 0.015/0.5 μg/mL) and against 3081 Staphylococcus aureus with >95% of the isolates inhibited at a MIC of ≤0.5 μg/mL; against 1410 levofloxacin-resistant Staphylococcus aureus isolates, >90% were inhibited by MIC ≤0.5 μg/mL. All isolates were inhibited at a MIC of ≤2 μg/mL. In addition, JNJ-Q2 demonstrated excellent activity (MIC(90), 0.015 μg/mL) against 569 isolates of beta-hemolytic streptococci (including 278 Streptococcus pyogenes and 161 Streptococcus agalactiae). JNJ-Q2 was the most potent fluoroquinolone tested overall and against all pathogens when compared directly to moxifloxacin, levofloxacin, and ciprofloxacin.     

Activity of JNJ-Q2 against Staphylococcus aureus isolated from patients with acute bacterial skin and skin-structure infection obtained during a Phase 2 clinical trial

JNJ-Q2, a fluorinated 4-quinolone, was very active against both methicillin-susceptible Staphylococcus aureus (n = 42; MIC(50/90), 0.008/0.12 μg/mL) and methicillin-resistant S. aureus (n = 69; MIC(50/90), 0.12/0.12 μg/mL) obtained from patients with acute bacterial skin and skin-structure infection (ABSSSI). Overall moxifloxacin and levofloxacin resistance rates were 31.5% and 46.9%, respectively. These favorable results support the continued clinical development of JNJ-Q2 to treat ABSSSI.     

European glycopeptide susceptibility survey of Gram-positive bacteria for 1995

In the European Glycopeptide Susceptibility Survey 7078 Gram-positive isolates collected in 1995 from 70 centers in 9 countries of Western Europe were examined, using a standardized, quantitative susceptibility testing method. Of the 7078 isolates, 6824 (96.4%) were tested by the national coordinating centers. Teicoplanin (mode MIC 0.5 μg/mL) was generally twice as active as vancomycin (mode MIC 1 μg/mL) against Staphylococcus aureus (n = 2852). All isolates were susceptible to vancomycin (MIC ≤4 μg/mL) and all but four to teicoplanin (MIC ≤8 μg/mL); these four isolates were of intermediate susceptibility (MIC 16 μg/mL). With coagulase-negative staphylococci (n = 1444), the distribution of MIC of teicoplanin was wider than for vancomycin. Two and two-tenths percent of coagulase-negative staphylococci excluding Staphylococcus haemolyticus required 16 μg/mL teicoplanin for inhibition (intermediate) and 0.4% ≥32 μg/mL (resistant). Among isolates of S. haemolyticus, 4.4% were of intermediate susceptibility (MIC 16 μg/mL) and 3.3% were resistant (MIC ≥32 μg/mL) to teicoplanin. However, this species represented only 6.3% of the isolates of coagulase-negative Staphylococcus spp. Generally, teicoplanin (mode MIC ≤0.12 μg/mL) was four to eight times more active than vancomycin (mode MIC ≤0.5 μg/mL) against the 770 streptococcal isolates. Glycopeptide-susceptible Enterococcus spp. (n = 1695) were generally four times more susceptible to teicoplanin (mode MIC 0.25 μg/mL) than to vancomycin (mode MIC 1 μg/mL). Combined vancomycin and teicoplanin (VanA phenotype) resistance was observed more frequently (9.3%) in isolates of Enterococcus faecium than in Enterococcus faecalis (0.8%). Four isolates of unspeciated enterococci (1.4%) also expressed this resistance phenotype. Four isolates of E. faecium and four of E. faecalis expressed the VanB-type (low-level, vancomycin only) resistance. Spain was the only country not to submit resistant E. faecium strains while resistant E. faecalis isolates came only from Spain and Italy.     

Antimicrobial susceptibility and molecular characteristics of 857 methicillin-resistant Staphylococcus aureus isolates from 16 medical centers in Japan (2008-2009): nationwide survey of community-acquired and nosocomial MRSA

This study is a nationwide survey of all clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates, including community-acquired MRSA (CA-MRSA), in Japan. A total of 857 MRSA clinical isolates were collected from the 16 institutions throughout Japan that participated in the survey (2008-2009). The drug susceptibility and staphylococcal cassette chromosome mec (SCCmec) typing and the presence of specific pathogenic genes were evaluated. The isolates comprised SCCmec type II (73.6%), type IV (20%), and type I (6%). The percentage of SCCmec type IV isolates was significantly higher in outpatients than in inpatients. Most of the isolated strains were sensitive to vancomycin (VCM, MIC ≤2 μg/mL), linezolid (MIC ≤4 μg/mL), and teicoplanin (MIC ≤8 μg/mL). Although most strains were sensitive to VCM, the MIC value of VCM for SCCmec type II strains was higher than that for SCCmec type IV strains. Only 4 (2.3%) of 171 SCCmec type IV strains were Panton-Valentine leukocidin (lukS/F-PV)-positive. Thus, this result indicates a unique feature of SCCmec type IV strains in Japan. The information in this study not only is important in terms of local public health but will also contribute to an understanding of epidemic clones of CA-MRSA.     

In vitro activity against Staphylococcus aureus of a novel antimicrobial agent, PRF-119, a recombinant chimeric bacteriophage endolysin

Antistaphylococcal activity of the novel chimeric endolysin PRF-119 was evaluated with the microdilution method. The MIC(50) and MIC(90) of 398 methicillin-susceptible Staphylococcus aureus isolates were 0.098 μg/ml and 0.391 μg/ml, respectively (range, 0.024 to 0.780 μg/ml). Both the MIC(50) and MIC(90) values of 776 methicillin-resistant S. aureus isolates were 0.391 μg/ml (range, 0.024 to 1.563 μg/ml). All 192 clinical isolates of coagulase-negative staphylococci exhibited MIC values of >50 μg/ml. In conclusion, PRF-119 exhibited very good activity specifically against S. aureus.