Mycosynthesis,characterization and antibacterial properties of AgNPs against multidrug resistant (MDR) bacterial pathogens of female infertility cases

Recently, biosynthesis of silver nanoparticles using bacteria, fungus and plants has emerged as a simple and viable alternative to more complex physical and chemical synthetic procedures. The present investigation explains rapid and extracellular synthesis of silver nanoparticles using fungus Fusarium oxysporum NGD and characterization of the synthesized silver nanoparticles using UV-Vis spectroscopy, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis. The size range of the synthesized silver nanoparticles was around 16.3–70 nm. The FTIR studies showed major peaks of proteins involved in the synthesis of silver nanoparticles. Further, antibacterial effect of the silver nanoparticles against multidrug resistant pathogens Enterobacter sp. ANT 02 [HM803168], Pseudomonas aeruginosa ANT 04 [HM803170], Klebsiella pneumoniae ANT 03 [HM803169] and Escherichia coli ANT 01 [HM803167] was tested using turbidometric assay at 10, 20, 30, 40 μg AgNPs/ml alone and in combination with ampicillin using agar well diffusion assay. All the resistant bacteria were found to be susceptible to the antibiotic in the presence of the silver nanoparticles.     

多重耐药铜绿假单胞菌的耐药性分析

目的分析2007年—2009年我院铜绿假单胞菌多重耐药(multidrug resistant,MDR)菌株对多种抗菌药物的耐药性变迁。方法收集2007年1月—2009年12月我院细菌室分离的铜绿假单胞菌,采用琼脂扩散法作敏感试验。结果 3年来共分离铜绿假单胞菌422株,其中MDR菌株100株,占23.70%。分离出的MDR菌株分布在呼吸科普通病房(13.00%)、呼吸重症监护病房(RICU)(29.00%)、外科病房(9.00%)、外科监护病房(SICU)(20.00%)、急诊科(5.00%)和其他内科病房(14.00%)。各科室中,分离出的MDR菌株数占所有标本分离的该菌株数的比例最高的是RICU(42.39%,39/92),其次为SICU(37.04%,20/54)。痰标本分离的MDR菌株占76.00%(76/100),其次为尿液(5.00%,5/100)。铜绿假单胞菌MDR菌株的分离率在3年期间无显著性差异。3年期间铜绿假单胞菌MDR菌株对头孢哌酮/舒巴坦耐药率最低(分别为25.00%、37.93%、40.48%);对所有检测的抗菌药物耐药率各年间无显著性差异。RICU与SICU分离的MDR菌株对亚胺培南、美罗培南耐药率显著高于其他普通病房,对其余检测的抗菌药物耐药率与其他病房无显著性差异。结论我院铜绿假单胞菌MDR菌株的耐药情况近年来十分严峻,在RICU与SICU,MDR菌株对碳青霉烯类耐药尤其严重,因此需严密监测细菌耐药性,指导合理使用抗菌药物。     

医院多药耐药菌感染的监测与分析

目的了解医院多药耐药菌（MDRO）感染分布情况和耐药性特点,为临床治疗多药耐药菌感染和预防控制提供依据。方法使用先德Sensititre全自动微生物分析仪及黑马D-96药敏板进行菌种鉴定和药敏试验,对多药耐药菌的分布进行调查分析。结果共分离多药耐药菌520株,多药耐药菌革兰阳性球菌占11.7%,革兰阴性杆菌占88.3%;前3位是大肠埃希菌、鲍曼不动杆菌、铜绿假单胞菌;主要分布在ICU、神经外科、呼吸科、神经内科,引起医院感染的部位主要是呼吸道、泌尿道及外科切口。结论多药耐药菌以革兰阴性菌为主,尤其是鲍曼不动杆菌,对常用抗菌药物几乎全部耐药,应加强多药耐药菌的监测,预防和控制多药耐药菌在院内感染中的传播与扩散。     

Antibacterial effects of antibiotics and cell-free preparations of probiotics against Staphylococcus aureus and Staphylococcus epidermidis associated with conjunctivitis

Conjunctivitis, caused by bacterial infections, represents health concern and diagnosis of the disease is pivotal for the proper selection of the treatment. The main causes of bacterial conjunctivitis vary in different countries. The current study investigated the common bacterial causes of bacterial conjunctivitis from eye clinics' attendants and evaluated the effectiveness of different therapeutic approaches. Eye swabs from patients, diagnosed with conjunctivitis, were assessed microbiologically and the isolated bacteria were identified using the standard biochemical identification and sequencing of the 16S rRNA gene. Antibiotics' susceptibility of the conjunctivitis-associated bacterial pathogens was evaluated against nineteen broad-spectrum antibiotics. In the meanwhile, cell-free preparations from probiotic Lactobacillus and Bifidobacterium strains were used to evaluate their antagonistic activities. Findings from this study showed that out of 52 specimen, 17 eye swabs from patients with conjunctivitis were bacterial culture-positive. The identity of the bacterial species, using the biochemical identification system, was Staphylococcus aureus (4 isolates) and S. epidermidis (13 isolates). Staphylococcus spp. showed susceptibility to linezolid, vancomycin, novobiocin, and fluoroquinolones (norfloxacin, ofloxacin, ciprofloxacin and levofloxacin). However, isolates from the two Staphylococcus spp. expressed resistance to penicillin G, oxacillin, and cephalexin. As alternatives to antibiotics, the growth of Staphylococcus spp., including isolates with antibiotic resistance, was inhibited by cell-free preparations of the 4 probiotic Lactobacillus and the 2 Bifidobacterium strains. These findings provide evidence that topical antibiotics such as fluoroquinolones are still effective antimicrobial agents against staphylococci associated with conjunctivitis whereas probiotic preparations could be promising for further research to pave the way for their therapeutic applications against ophthalmic diseases.     

Influence of serum protein binding on the uptake and retention of idarubicin by sensitive and multidrug resistant human leukemic cells

Objective: The objectives of the investigations were (1) to determine the binding characteristics of idarubicin (IDA) in human serum and cell culture solutions, (2) to determine the effect of protein binding on the uptake and retention of IDA by human leukemic cell lines in culture and the extent to which R-verapamil (R-VRP), an inhibitor of the P-glycoprotein (P-gp) transporter, can modulate these processes, and (3) to assess the importance of protein binding on cytostatic and chemosensitizer action in vivo. Methods: The protein binding of IDA was determined using equilibrium dialysis. Cell uptake of IDA was measured using sensitive and P-gp-containing resistant human leukemic cell lines (HL-60 and HL-60-Vinc) in vitro. IDA was assayed spectrophotofluorometrically. Results: In the incubation media examined, the free fraction of IDA varied more than seven-fold from approximately 60% in 15% fetal calf serum (FCS)/PBS to only 8% in human serum. Cellular uptake of IDA was approximately three times higher in medium containing low protein concentrations. R-VRP eliminated the difference in IDA uptake between resistant and sensitive cell lines and this was the case when the cells were incubated in solutions containing both high and low protein concentrations. However, R-VRP did not overcome the effect of high protein concentrations on IDA uptake. Conclusions: Plasma protein binding is an important determinant for cellular uptake of IDA in vitro. This should be taken into account when interpreting results of in vitro functional assays with patient material. Chemosensitizers such as R-VRP are effective in both high and low protein solutions. Investigations like these may be useful for evaluating cytostatic efficacy and chemosensitizer action in vivo. Received: 10 August 1998 / Accepted in revised form: 15 January 1999     

硝酸银使临床分离多重耐药革兰氏阳性菌和革兰氏阴性菌重新对阿米卡星敏感（英文）

高浓度的硝酸银可抑制所有检测的临床分离耐多重药菌株（最小抑菌浓度为32–64μM）。本研究报道了阿米卡星与亚致死量（15μM）的硝酸银在体外联用对临床分离多重耐药菌的作用。硝酸银可使原本已对阿米卡星耐药的泛耐药鲍曼不动杆菌和耐甲氧西林金黄色葡萄球菌重新变敏感（将原本都大于128μg/mL的最小抑菌浓度分别降低至2–16μg/mL和32μg/mL）。硝酸银同样可以将阿米卡星对能够产生超广谱β内酰胺酶的绿脓杆菌和大肠杆菌的最小抑菌浓度分别由16–32μg/mL和16μg/mL降至〈1–4μg/mL和〈1μg/mL。     

多重耐药肺炎克雷伯杆菌模型构建及外排抑制剂对其药物敏感性影响的研究

目的研究耐多药肺炎克雷伯杆菌模型的体外构建及泵抑制剂对其药物敏感性的影响。方法收集临床肺炎克雷伯杆菌,运用左旋氧氟沙星从低浓度至高浓度在体外诱导其成为对喹诺酮、头孢菌素、青霉素、氯霉素、四环素等多种抗生素的耐药株,并排除产ESBLs菌株。分别选用外排抑制剂(EPI)羰基氰氯苯腙(CCCP)及奥美拉唑在20μg/ml及40μg/ml两种不同浓度下与细菌共同培养后,运用琼脂稀释法测定细菌对左旋氧氟沙星敏感性的改变。同时运用纸片扩散法检测耐药株对多重抗生素的药物敏感性。结果起始运用亚抑菌浓度并逐步加大的梯度浓度法体外能成功构建多重耐药肺炎克雷伯杆菌模型,在CCCP耐药性逆转实验中,泵阳性株达53%,CCCP及奥美拉唑的抑制外排作用有统计学差异,尚不能认为外排抑制剂在高低两种浓度下对菌株的药物敏感性影响有统计学差异。运用外排抑制剂后菌株对多种抗生素的抑菌环直径有不同程度的增大。结论不规范长期低浓度应用喹诺酮类可以诱变出多重耐药菌株,外排机制在介导耐多药细菌形成中起着重要的作用,CCCP比奥美拉唑能更有效的抑制细菌主动外排,但是都不能完全逆转其耐药性。     

3-aminoquinazolinediones as a new class of antibacterial agents demonstrating excellent antibacterial activity against wild-type and multidrug resistant organisms

The 3-aminoquinzolinediones represent a new series of antibacterial agents structurally related to the fluoroquinolones. They are inhibitors of bacterial gyrase and topoisomerase IV and demonstrate clinically useful antibacterial activity against fastidious Gram-negative and Gram-positive organisms, including multidrug- and fluoroquinolone-resistant organisms. These agents also demonstrate in vivo efficacy in murine systemic infection models.     

盐酸小檗碱、黄芩苷与抗菌药物联用对多重耐药鲍曼不动杆菌作用研究

目的探讨盐酸小檗碱、黄芩苷与6种抗菌药物(头孢他啶、哌拉西林-他唑巴坦、亚胺培南西司他丁钠、氨曲南、左氧氟沙星、加替沙星)对多重耐药鲍曼不动杆菌的联合抑菌作用。方法根据临床药敏结果选取7株鲍曼不动杆菌多重耐药菌株作为实验对象。用微量稀释法测定盐酸小檗碱、黄芩苷分别与6种抗菌药物的联合抑菌效应。结果盐酸小檗碱与亚胺培南西司他丁钠、氨曲南联用表现为协同作用。黄芩苷与氨曲南表现为协同作用。结论盐酸小檗碱、黄芩苷与某些抗菌药物联用后对多重耐药鲍曼不动杆菌的抗菌活性有协同作用,可能对多重耐药鲍曼不动杆菌的治疗有所帮助。     

抗菌药物对耐甲氧西林凝固酶阴性葡萄球菌的体外抗菌活性研究

凝固酶阴性葡萄球菌已成为内感染的重要病原菌，并且其中有相当部分为耐甲氧西林凝固酶阴性葡萄球菌，这类菌株常同时对β－内酰胺类，大环内酯类抗生素等药物呈现高的耐药性。     

Collateral sensitivity of resistant MRP1-overexpressing cells to flavonoids and derivatives through GSH efflux

The multidrug resistance protein 1 (MRP1) is involved in multidrug resistance of cancer cells by mediating drug efflux out of cells, often in co-transport with glutathione (GSH). GSH efflux mediated by MRP1 can be stimulated by verapamil. In cells overexpressing MRP1, we have previously shown that verapamil induced a huge intracellular GSH depletion which triggered apoptosis of the cells. That phenomenon takes place in the more global anticancer strategy called “collateral sensitivity” and could be exploited to eradicate some chemoresistant cancer cells. Seeking alternative compounds to verapamil, we screened a library of natural flavonoids and synthetic derivatives. A large number of these compounds stimulate MRP1-mediated GSH efflux and the most active ones have been evaluated for their cytotoxic effect on MRP1-overexpressing cells versus parental cells. Interestingly, some are highly and selectively cytotoxic for MRP1-cells, leading them to apoptosis. However, some others do not exhibit any cytotoxicity while promoting a strong GSH efflux, indicating that GSH efflux is necessary but not sufficient for MRP1-cells apoptosis. In support to this hypothesis, structure activity relationships show that the absence of a hydroxyl group at position 3 of the flavonoid C ring is an absolute requirement for induction of MRP1-cells death, but is not for GSH efflux stimulation. Chrysin (compound 8) and its derivatives, compounds 11 and 22, exhibit a high selectivity toward MRP1-cells with a IC₅₀ value of 4.1 μM for compound 11 and 4.9 μM for chrysin and compound 22, making them among the best described selective killer compounds of multidrug ABC transporter-overexpressing cells.     

肺炎克雷伯菌和大肠埃希菌的分布与耐药性监测

目的了解我院肺炎克雷伯菌与大肠埃希菌在不同临床标本中的分布及耐药特点。方法采用K-B法药敏进行药敏试验并应用WHONET 5.4软件和SPSS 17.0对数据进行统计分析。结果医院产ESBLs大肠埃希菌和肺炎克雷伯菌总检出率分别为30.9%和22.7%,且对绝大多数抗菌药物的耐药率高于30%;产ESBLs大肠埃希菌和肺炎克雷伯菌在不同标本间对同一抗菌药物的耐药率有显著差别。结论肺炎克雷伯菌和大肠埃希菌在各类临床标本中的检出率和耐药率有差异,及时了解其耐药特点对合理应用抗菌药物十分重要。     

双氢杨梅树皮素与4种抗生素联合对多重耐药金黄色葡萄球菌体外抗菌作用研究

目的 研究双氢杨梅树皮素(ampelopsis, APS)与4种抗生素联合用药对多重耐药金黄色葡萄球菌(Staphylococcus aureus, SA)体外抗菌作用效果。方法 采用多步诱导法和琼脂平皿二倍稀释法，以青霉素为对照，通过测定诱导前后最低抑菌浓度(minimal inhibitory concentration, MIC)，评价标准SA是否容易对APS产生耐药；采用棋盘稀释法测定3个不同浓度的APS分别与4种抗生素联用对多重耐药SA的协同抗菌指数(FICI)。结果 敏感的标准SA体外诱导288h后，对32×MIC浓度下的青霉素产生耐药，对APS未产生耐药；15.625μg/mL APS分别与青霉素、四环素、庆大霉素、氯霉素联用对多重耐药SA的FICI分别为0.37、0.63、1.13和1.13；31.25μg/mL APS分别与4种抗生素联用FICI分别为0.50、0.38、1.25和0.75；62.5μg/mL APS分别与4种抗生素联用FICI分别为0.51、0.63、0.53和0.56。结论 APS不易诱导标准SA产生耐药，且APS与青霉素或四环素联用表现出协同效应，与庆大霉素或氯霉素联用表现出相加效应。     

耐头孢他啶大肠埃希氏菌超广谱β-内酰胺酶分析

目的　研究对头孢他啶耐药的大肠埃希氏菌产生的 β 内酰胺酶分子特性。方法　用平皿二倍稀释法挑选头孢他啶耐药的大肠埃希氏菌 ;用头孢他啶、头孢他啶 /克拉维酸、头孢噻肟、头孢噻肟 /克拉维酸纸片扩散法药物敏感实验确定超广谱 β 内酰胺酶产生菌 ;测定 β 内酰胺酶的分子量、等电点 ;提取质粒 ,基因组DNA进行PCR扩增测序。结果　共对 4株耐头孢他啶的大肠埃希氏菌产生的 β 内酰胺酶进行了分子特性研究 ,它们的MIC值 3 2～ 64mg/L ;纸片法联合药物敏感实验结果证明这 4株大肠埃希氏菌产超广谱 β 内酰胺酶 ;酶的分子量均是 2 8.10ku ;酶等电点测定结果显示有 2株大肠埃希氏菌各产生一种 β 内酰胺酶 ,它们的等电点是 6.8;另外 2株大肠埃希氏菌各产生 2种 β 内酰胺酶 ,它们的等电点分别是 6.8和 7.68。 4株大肠埃希氏菌都含有 1个质粒 ,PCR扩增结果为TEM型基因 ,其氨基酸序列与TEM 197%～ 98%等同 ,在 117位及 118位发生了氨基酸变异。结论　 4株耐头孢他啶的大肠埃希氏菌可能产生新的抑制剂敏感的TEM型超广谱酶     

In vitro pharmacokinetics and pharmacodynamics of levofloxacin against plasmid-mediated quinolone resistant Escherichia coli

AIM： Bacterial resistance to quinolones has traditionally mediated by alteration of the quinolone targets and/or overproduction of efflux pump. Recently, a new mechanism, the plasmid-mediated quinolone resistance named qnr, has been clarified. Qnr and its homologus are widely distributed among gram-negative bacteria. The presence of qnr only slightly elevates the resistance level, however it facilitates the selection of highly resistant strains. In our study, we examined the probable influence of such phenomenon to the clinical regimens of levofloxacin. METHODS： Invitro hollow fiber infection model simulating oral two-compartment pharmacokinetic model was established. In the model, bacteria was incubated in the peripheral compartment without ‘washout effect＇. We designed two therapeutic regimens of levofloxacin, including 500 mg qd （peak 5.12 mg/L; half-time 6.9 h） and 700 mg qd （peak 9.46 mg/L; half-time 6.9 h） for 3 days against E. coli J53 and E. coli 650 _ 3, which canting qnr positive plasmid.[第一段]