ε-聚赖氨酸对白念珠菌抑菌活性及机制研究

目的 研究ε-多聚赖氨酸(ε-poly-L-lysine, ε-PL)对白念珠菌(Candida albicans)的抑菌活性及抑菌机制。方法 以白念珠菌的标准菌株ATCC64548(氟康唑敏感株)、ATCC64550(氟康唑耐药株)以及临床收集的50株菌为实验菌株,按照CLISI- M27文件中的微量稀释法测定ε-多聚赖氨酸的MIC、MFC和SMIC50值;绘制48h内的浮游菌株时间-生长曲线和生物膜抑制-时间曲线;连续观测并记录4h内的芽管形成率和芽管长度;测定药物处理前后白念珠菌的丙二醛和活性氧(ROS)含量。结果 ε-PL对白念珠的最低抑菌浓度(MIC)为512μg/mL,最低杀菌浓度(MFC)为1024μg/mL,SMIC50为512μg/mL,ε-PL对白念珠菌浮游菌及生物膜的抑菌作用随着浓度的升高作用愈明显。抑菌-时间曲线结果表明ε-PL对白念珠菌的浮游菌和生物膜在12h左右即产生明显抑制作用。芽管实验的结果表明高浓度的ε-PL对白念珠菌的芽管形成率及芽管长度具有明显抑制作用。ε-PL作用于白念珠菌后MDA和ROS含量呈现上升趋势,并且与药物浓度大小成正相关。结论 ε-PL对白念珠菌浮游菌株及生物膜均有良好的抑制作用,高浓度ε-PL对白念珠菌主要毒力菌丝有明显抑制作用,ε-PL作用导致白念珠菌内产生大量的活性氧(ROS)以及产生一定程度的脂质氧化,提示ε-PL可能通过氧化作用发挥抑菌效果。     

In vitro analysis of flufenamic acid activity against Candida albicans biofilms

In a recent high-throughput screen against specific Candida albicans drug targets, several compounds that exhibited non-specific antifungal activity were identified, including the non-steroidal anti-inflammatory drug flufenamic acid (FFA). This study sought to determine the effect of different doses of FFA, alone or in combination with fixed concentrations of the standard antifungal agents amphotericin B (AmB), caspofungin (CAS) or fluconazole (FLU), for the prevention and treatment of C. albicans biofilms. Biofilms were formed in a 96-well microplate followed by evaluation of antifungal activity using the XTT assay. FFA concentrations of ≥512 mg/L demonstrated >80% prevention of biofilm formation. FFA concentrations of 1024 mg/L demonstrated >85% reduction of mature biofilms. When FFA (≥8 mg/L) was used in combination with FLU (32 mg/L), antifungal activity increased to 99% for the prevention of biofilm formation. Similarly, when a FFA concentration of ≥8 mg/L was used in combination with either AmB (0.25 mg/L) or CAS (0.125 mg/L), antifungal activity also increased up to 99% for the prevention of biofilm formation. The inhibitory effect of FFA on C. albicans biofilms has not been reported previously, therefore these findings suggest that FFA in combination with traditional antifungals might be useful for the treatment and prevention of C. albicans biofilms.     

不同标本类型中分离出白念珠菌对抗真菌药物敏感性分析

目的 探讨从不同类型标本中分离的白念珠菌菌株对常用抗真菌药物的耐药谱，为临床白念珠菌感染性疾病诊断和治疗提供理论和实验依据。方法 用真菌鉴定卡及Rosco真菌药敏纸片对分离出的所有白念珠菌作菌种鉴定和药敏实验，采用μ检验分析从男性生殖道分泌物、女性生殖道分泌物和痰液中分离出白念珠菌的药物敏感特点。结果 从痰液中分离出的白念珠菌对5-氟胞嘧啶、两性霉素B、咪康唑、酮康唑和制霉菌素敏感率分别为97．8％、98．9％、83．1％、87．6％和99．9％；男性尿道分泌物中自念珠菌的敏感率分别是76．1％、81．1％、65．3％、71．6％和86．0％；女性生殖道分泌物中菌株分别是58．4％、71．3％、61．4％、62.4％和86.1％，三组之间具有统计学意义（P〈0．01）。结论 不同标本中分离出的白念珠菌对抗真菌的敏感性有显著性差异。     

Antifungal potential of Sideroxylon obtusifolium and Syzygium cumini and their mode of action against Candida albicans

Context The emergence of resistant pathogens and toxicity of antifungals have encouraged an active search for novel candidates to manage Candida biofilms.

Objective In this study, the little known species Sideroxylon obtusifolium T.D. Penn (Sapotacea) and Syzygium cumini (L.) Skeels (Myrtaceae), from the Caatinga biome in Brazil were chemically characterized and explored for their antifungal potential against C. albicans.

Materials and methods We determined the effects of hydroalcoholic extracts/fractions upon fungal growth (minimum inhibitory and fungicidal concentrations, MIC/MFC), biofilm morphology (scanning electron microscopy) and viability (confocal laser scanning microscopy), proposed their mode of action (sorbitol and ergosterol assays), and finally investigated their effects against macrophage and keratinocyte cells in a cell-based assay. Data were analysed using one-way analysis of variance with Tukey-Kramer post-test (α?=?0.05).

Results The n-butanol (Nb) fraction from S. obtusifolium and S. cumini extract (Sc) showed flavonoids (39.11?±?6.62?mg/g) and saponins (820.35?±?225.38?mg/g), respectively, in their chemical composition and demonstrated antifungal activity, with MICs of 62.5 and 125?μg/mL, respectively. Nb and Sc may complex with ergosterol as there was a 4–16-fold increase in MICs in the presence of exogenous ergosterol, leading to disrupted permeability of cell membrane. Deleterious effects were observed on morphology and viability of treated biofilms from concentrations as low as their MICs and higher. Sc was not toxic to macrophages and keratinocytes at these concentrations (p?> 0.05), unlike Nb.

Conclusions Nb and Sc demonstrated considerable antifungal activity and should be further investigated as potential alternative candidates to treat Candida biofilms.     

A representative of arylcyanomethylenequinone oximes effectively inhibits growth and formation of hyphae in Candida albicans and influences the activity of protein kinases in vitro

In this study, we applied various assays to reveal new activities of phenylcyanomethylenequinone oxime-4-(hydroxyimino) cyclohexa-2,5-dien-1-ylidene](phenyl)ethanenitrile (4-AN) for potential anti-microbial applications. These assays demonstrated (a) the antimicrobial effect on bacterial and fungal cultures, (b) the effect on the in vitro activity of the kinase CK2, (c) toxicity towards human erythrocytes, the Caco-2 cancer cell line, and embryonic development of Zebrafish. We demonstrated the activity of 4-AN against selected bacteria and Candida spp. The MIC ranging from 4?µg/ml to 125?µg/ml proved effective in inhibition of formation of hyphae and cell aggregation in Candida, which was demonstrated at the cytological level. Noteworthy, 4-AN was found to inhibit the CK2 kinase with moderate potency. Moreover, at low concentrations, it did not exert any evident toxic effects on human erythrocytes, Caco-2 cells, or Zebrafish embryos. 4-AN can be a potential candidate as a novel drug against Candida infections.     

卡泊芬净对生物膜态白色念珠菌体外抑菌作用的试验研究

目的:检测卡泊芬净对生物膜态白色念珠菌分离株的抑菌作用,探讨临床治疗其相关感染的最适治疗剂量。方法:分别测定卡泊芬净对10株白色念珠菌临床株游离态及生物膜态的半数抑菌浓度(MIC50),并对比观察不同浓度卡泊芬净作用下白色念珠菌的增殖活性。结果:卡泊芬净对游离态白色念珠菌的MIC50为0.125～0.5mg.L-1,对生物膜态白色念珠菌的MIC50为0.25～256mg.L-1,当卡泊芬净浓度高于白色念珠菌MIC50时,全部游离态白色念珠菌的增殖活性几乎完全受到抑制,但有7株生物膜态白色念珠菌的增殖活性再次增强,且大于阳性对照的50%。结论:卡泊芬净对生物膜态白色念珠菌有抑菌作用,但并不呈浓度依赖性,当其用于治疗生物膜态白色念珠菌相关感染时的最适治疗剂量有待临床研究验证。     

Antimicrobial activity of cefetamet against clinically isolated microbial strains collected from urban RTI patients]

The authors studied antimicrobial activities of cefetamet (CFMT) and other leading oral antimicrobials of beta-lactam class against clinically isolated strains from urban respiratory tract infection (RTI) patients from January to March, 1992. 1. CFMT showed potent antimicrobial activities against "3 primary pathogens" of RTIs i.e., Streptococcus pyogenes, Streptococcus pneumoniae, and Haemophilus influenzae, but the drug had a slightly higher MIC than those of a few oxime-type cephems already on the market. 2. CFMT was as stable as cefixime to beta-lactamase, generated by Moraxella subgenus Branhamella catarrhalis, which reduces the antimicrobial activity of cephems. 3. Blood concentrations of CFMT after administering cefetamet pivoxil (CFMT-PI), an oral form of the drug, exceeded the MIC80 against the "3 primary pathogens" as well as M. (B) catarrhalis and Klebsiella pneumoniae, for a duration of approximately 9 and 11 hours, respectively, after single doses of 250 and 500 mg. This suggests that CFMT could remain above the MICs for a sufficient time period with twice daily dosages of normal dose levels. 4. It is concluded that CFMT-PI will be useful for treating urban RTIs.     

侵袭性白念珠菌感染的危险因素及耐药性变迁

目的 分析四川大学华西医院住院患者侵袭性白念珠菌感染的分布情况、可能的危险因素以及真菌耐药性变化,为临床预防和合理用药提供依据.方法 对四川大学华西医院2010年1月到2012年12月100例侵袭性白念珠菌感染患者的临床资料进行回顾性分析,分析并总结其标本来源、科室分布、年龄分布、感染的危险因素、抗菌药物使用情况以及真菌耐药率的变迁.结果 在侵袭性白念珠菌感染中,血流感染最为多见,占55％,感染患者多为ICU重症患者,占35％.年龄分布中位数为53.5岁.可能相关危险因素中外科手术和气管插管/切开、机械通气分别占74.6％和46.5％,有94例(82.5％)使用过抗菌药物.3年来我院白念珠菌对氟康唑、伏立康唑、两性霉素B耐药率为0％,对5-氟胞嘧啶和伊曲康唑的耐药率分别保持在4.1％和27.7％以下.结论 白念珠菌是ICU重症患者的血流侵袭性真菌感染中重要的病原菌,外科手术和气管插管/切开及呼吸机的使用是最显著侵袭性白念感染的两大危险因素.虽然目前临床常用抗真菌药物能覆盖侵袭性白念珠菌的治疗,但仍应加强对重点科室以及有相关危险因素患者的监测,重视培养鉴定与药敏结果对临床用药的指导,以减少耐药菌的出现与流行.     

Antimicrobial and antibiofilm activity of Baccharis psiadioides essential oil against antibiotic-resistant Enterococcus faecalis strains

Context: Baccharis psiadioides (Less.) Joch. Müller (Asteraceae) is considered as a producer of bioactive essential oils and is used in south Brazilian folk medicine for its proprieties as stimulant, antipyretic, anti-inflammatory and as an antidote for snake bites.

Objective: To verify the antimicrobial and antibiofilm activities of the essential oil of B. psiadioides (EOBP) against antibiotic-resistant Enterococcus faecalis.

Materials and methods: The initial evaluation of EOBP activity was conducted by the agar and microdilution methods against 13 antibiotic-resistant E. faecalis strains. The antibiofilm effect was determined by the application of EOBP in the earlier adherent cells or to the stabilized biofilm for 24?h and was evaluated by crystal violet, viability and scanning electron microscopy (SEM) assays. Chemical composition of EOBP was determined by gas chromatography (GC/FID – GC/MS).

Results: The MIC values for EOBP were at least 1.25% and 4–16% for agar and microdilution assays, respectively. The EOBP reduced the microbial adherence and the viability of the cells, but did not cause the complete disruption of biofilms. SEM images indicate that EOBP influences the adherence of cells to a surface. The monoterpene β-pinene was the major constituent identified in EOBP.

Conclusion: This research shows the ability of EOBP to control resistant E. faecalis strains and to reduce the biofilm amount attached to abiotic surfaces, indicating its role as a promising new natural antimicrobial agent. Moreover, these results further contribute to the growing number of studies of plant natural products which suggest that these compounds can combat resistant microorganisms.     

白色念珠菌酮康唑抗药株的筛选

目的获得白色念珠菌的酮康唑抗药株。方法采用美国国家临床实验标准化委员会 (NC CLS)推荐的最小抑菌浓度 (MIC)测定法 ,从 8株不同来源的白色念珠菌中筛选出YS2 0 1 (MIC为0 0 62 μg/mL)作为出发菌株 ,分别利用紫外线 (UV)和亚硝基胍 (NTG)对其原生质体进行诱变。结果经大量筛选 ,得到抗药突变株UP1 1及NP2 9,其MIC分别达到 3 5 μg/mL和 75 μg/mL。结论获得酮康唑抗药株 ,突变株的抗药特性稳定。     

五倍子鞣质提取物对白假丝酵母的抗菌活性研究

目的 研究五倍子鞣质提取物对白假丝酵母的体外抗茵活性.方法 通过超声波提取五倍子有效成分鞣质,福林-酚比色法检测鞣质含量,采用微量稀释法检测五倍子鞣质提取物对白假丝酵母的最低抑菌浓度(MIC)和最低杀菌浓度(MFC),以最低抑茵浓度药物作用白假丝酵母6、12、24h,通过普通光学显微镜直接观察白假丝酵母形态结构的变化,并用吖啶橙/溴化乙锭染色,通过荧光显微镜观察白假丝酵母的死亡方式.结果 五倍子鞣质提取物对白假丝酵母的最低抑菌浓度为10.76 mg/mL,最低杀菌浓度为21.52mg/mL;五倍子鞣质提取物可导致白假丝酵母细胞变形,形态结构改变,最终导致其死亡;同时抑制细胞发芽和假菌丝的形成.结论 五倍子鞣质提取物对白假丝酵母有抑制和杀灭作用.     

Antifungal Activity of Plant Extracts against Candida Species from Oral Lesions

Seventy five patients with oral lesions attending the different departments of Rajah Muthiah Medical College and Hospital, Annamalai University were screened for Candida. Forty six (61.3%) Candida strains were isolated from the oral lesions. Of the 46 Candida strains, Candida albicans accounted for 35 (76.08%), Candida glabrata for 5 (10.86%), Candida tropicalis and Candida krusei for 2 (4.34%) each and Candida parapsilosis and Candida guilliermondii for one (2.17%) each. Antifungal activity of ethanol extracts of five plant species that included Syzygium jambolanum, Cassia siamea, Odina wodier, Momordica charantia and Melia azedarach and two algal species, Sargassum wightii and Caulerpa scalpelliformis were tested against 25 isolated strains by disc diffusion method. Antifungal activity was observed at 100 mg/ml for Syzygium jambolanum, Cassia siamea and Caulerpa scalpelliformis and at 10 mg/ml for Sargassum wightii.     

Antimicrobial activity of ethanol extracts of Agaricus brasiliensis against mutans streptococci

This study evaluated the antimicrobial activity of three different ethanol extracts of Agaricus brasiliensis S. Wasser et al. (Agaricaceae) on the growth and cell adherence of mutans streptococci. Crude ethanol extracts (100% EtOH, 75% EtOH, and 50% EtOH, v/v) obtained from dried basidiomes of A. brasiliensis were assessed against Streptococcus mutans UA159 and Streptococcus sobrinus 6715 by the agar diffusion method, determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and inhibition of cell adherence to a glass surface. In the agar diffusion method, only the 100% ethanol extract revealed inhibition of bacterial growth. Yet, in MIC and MBC tests, the three extracts presented antimicrobial properties and MIC and MBC values between 87.4 and 444.5 μg mL^?1. The MBC was predominantly similar to MIC against S. mutans, but only the 75% ethanol extract was bactericidal against S. sobrinus. Among the ethanol extracts tested, the 100% ethanol extract was the most active (MIC 87.4 μg mL^?1). The cellular adherence also was inhibited at concentrations from 100 to 400 μg mL^?1 of 50% and 75% ethanol extracts. These results provide promising baseline formation for the potential use of A. brasiliensis against mutans streptococci. These findings warrant more in-depth studies of the active principles of this mushroom ethanol extract.     

Investigation of the antifungal activity of carvacrol against strains of Cryptococcus neoformans

Background: Cryptococcus neoformans is the etiologic agent of opportunistic systemic fungal infection cryptococcosis, which affects individuals with compromised immune systems. Thus, natural products research has become important, since monoterpenes such as carvacrol, a promising molecule in the search antifungal agents, have shown significant biological activity.

Objective: The study aimed to investigate the antifungal activity and mode of action of carvacrol against strains of C. neoformans.

Methods: The minimum inhibitory concentration (MIC) was determined by microdilution method. Minimum fungicidal concentration (MFC) was performed by seeding technique on solid media. Studying the mode of action was performed using broth microdilution.

Results: The MIC ranged from 25 to 81?μg/mL and the MFC ranged from 25 to 102?μg/mL. Carvacrol bonded to exogenous ergosterol and cholesterol.

Discussion: The results suggest that carvacrol has antifungal activity against C. neoformans and its mode of action is related to fungal membrane instability.

Conclusions: The phytoconstituent carvacrol may eventually become a drug; however, further studies are needed to elucidate its mechanism.     

Antimicrobial activity of dequalinium chloride against leading germs of vaginal infections

Dequalinium chloride (CAS 522-51-0) and povidone iodine (CAS 25655-41-8) are known as antiseptic agents and used in the local treatment of vaginal infections. Clotrimazole (CAS 23593-75-1) is an anti-fungal drug and applied primarily in the therapy of vulvo-vaginal candidiasis and to a lesser extent in bacterial vaginosis and trichomoniasis. However, antimicrobial activities of those three agents in comparison to each other have not been reported so far. To address this issue the antimicrobial activities of these agents against 18 germs relevant to vaginal infections were determined. The tested species are representatives of the genera Staphylococcus, Streptococcus, Enterococcus, Listeria, Escherichia, Proteus, Gardnerella, Bacteroides, Prevotella, Porphyromonas, Candida, and Trichomonas. All micro-organisms were susceptible to dequalinium chloride with the exception of Proteus mirabilis. At a given dose, the activity of dequalinium chloride was higher as compared to the other substances. In view of its wide antimicrobial spectrum dequalinium chloride is an efficient alternative in the local therapy of vaginal infections such as fluor vaginalis, bacterial vaginosis, aerobic vaginitis, vulvo-vaginal candidiasis and trichomoniasis.     

Antimicrobial activities of meropenem against clinically isolated strains in 1999]

We determined the antibacterial activity of meropenem (MEPM) and control drugs against clinical isolates of 310 strains of Gram-positive bacteria (14 species), 590 strains of Gram-positive bacteria (21 species), and 120 strains of anaerobic bacteria (10 species) in 1999. We compared the results thus obtained with those in 1993 and 1997. The results were as follows; 1. MEPM showed excellent antibacterial activities against most of the species tested, except for MRSA, E. faecium, E. avium, and methicillin-resistant S. epidermidis (MRSE). 2. MEPM had much higher activity than IPM and PAPM against Gram-negative bacteria including S. marcescens and P. aeruginosa, part of which have been reported to produce metallo-beta-lactamase. 3. There was little difference in the susceptibility of clinical isolates to MEPM between 1993 and 1999. Thus MEPM was shown to retain its potent and broad antibacterial activity now at the same level as before available for use in 1995.     

聚乙烯亚胺单独及与三种抗菌药物联用对白念珠菌的体外抗菌活性

目的评估多支链的阳离子高分子聚合物——聚乙烯亚胺(PEI)单独及与三种不同类别的常规抗菌药物(两性霉素B、氟康唑和多黏菌素B)联合使用对白念珠菌(MY7245和MY7238)的两种临床分离物的抗真菌活性。方法通过体外实验测定不同分子质量聚乙烯亚胺单独及与三种不同类别的常规抗菌药物联合使用对两株白念珠菌的最小抑菌浓度和杀灭时间,确定PEI单独及联合使用的体外抗真菌活性。结果分子量在2～745ku范围内的PEI均对这两种白念珠菌产生很好的抗真菌活性,且分子量小的PEI比分子量大的PEI的抗菌作用更显著。与单独作用的PEI相比,分子量较大的PEI与常规药物联合使用时可产生较强的协同作用。在体外致死研究实验中可以看到,PEI-两性霉素B和PEI-氟康唑结合物可以提高抑菌作用,但PEI-多黏菌素B结合物却拮抗抑菌作用。结论PEI单独与联合使用均对白念珠菌产生很好的抗菌效果。     

Antimicrobial activity of dactimicin against aerobic and anaerobic bacteria isolated from intra-abdominal infections

The in vitro antimicrobial activity of dactimicin against aerobic and anaerobic bacteria isolated from intra-abdominal infections was compared to those of gentamicin and metronidazole. The data obtained show that dactimicin is a promising new aminoglycoside covering aerobic bacteria and that it may be used together with an antianaerobic agent in the treatment of these infections.