葛根芩连口服液抗菌抗病毒作用

葛根芩连汤是张仲景的名方,本品是其改剂型。它具有清热、解毒功效,用于腹泄和痢疾的治疗。现将其抗菌抗病毒结果报告如下。 1.体外抗菌作用:采用试管二倍稀释法,测定本品的最小抑菌浓度。将测出最低抑菌浓度,依次将未见细菌生长的各培养物.分别吸取0.1ml倾倒于平皿上,37℃再培养18小时,平皿上菌落数少于5个的最小稀释度的药物浓度,即为该药的最低杀菌浓度。葛根芩连口服液的最低杀菌浓度:埃希氏大肠杆菌:62.5mg/ml;志贺氏痢疾杆菌:62.5mg/ml;肺炎克雷伯氏菌:62.5mg/ml;A群链球菌:62.5mg/ml;金黄色葡萄球菌:125mg/ml。对     

体外抑菌试验评价核糖体表达筛选的抗菌肽活性

目的 观察体外无细胞核糖体表达系统筛选得到的、能与细菌膜结合的多肽的体外抑菌活性变化,初步评价该筛选系统的可行性.方法 采用核糖体展示系统和细胞膜模型筛选可结合于细胞膜的多肽,对筛选的多肽进行结构预测分析.选择形成α-螺旋结构可能性大、溶解性尚可的多肽(C13)进行合成.利用改良的微量肉汤稀释法测定C13和硫酸庆大霉素对G+(金黄色葡萄球菌)和G-(大肠杆菌、伤寒杆菌)细菌的抗菌活性--最小抑菌浓度(MIC)和最小杀菌浓度(MBC).结果 C13对试验细菌的MIC均为400 mg/L,但在现有浓度范围对试验菌的MBC则未测得.结论 体外无细胞核糖体表达系统筛选的抗菌肽C13具有一定的抑菌活性,表明利用人工膜模型和核糖体表达进行抗菌肽筛选的方法是可行的,但有效抗菌肽的筛选需进一步的抑菌试验证实.     

负载抗菌药物的骨水泥的药物释放实验研究

目的 揭示负载抗菌药物的骨水泥的药物释放浓度、持续时间、药物残留程度及低于最小有效抑菌浓度的释放时间,为合理应用抗菌药物提供理论依据。方法 通过对负载盐酸万古霉素和亚胺培南西司他丁钠的骨水泥进行体外洗提实验,采用高效液相色谱法检测分析两种负载抗菌药物的骨水泥的药物释放浓度、释放持续时间和药物残留程度。结果 ①负载抗菌药物的骨水泥第一天药物释放量最大,后逐渐持平,且释放时间较长,释放浓度较低;②截止到第7周盐酸万古霉素、亚胺培南西司他丁释放量分别只占总负载量的15%、25%;③盐酸万古霉素第1周后释放浓度低于最小有效抑菌浓度,亚胺培南西司他丁钠第7周后释放浓度低于最小有效抑菌浓度。结论 载抗菌药物骨水泥存在长时间药物残留现象,是导致持续低于最小有效抑菌浓度的主要原因。此种现象不但对细菌起不到抑菌作用,而且是诱导细菌耐药性的危险因素。     

负载抗菌药物骨水泥的药物释放实验研究

目的揭示负载抗菌药物骨水泥的药物释放浓度、持续时间、药物残留程度及低于最小有效抑菌浓度的释放时间,为合理应用抗菌药物提供理论依据。方法通过对负载盐酸万古霉素和亚胺培南西司他丁钠的骨水泥进行体外洗提实验,采用高效液相色谱法检测分析两种负载抗菌药物的骨水泥的药物释放浓度、释放持续时间和药物残留程度。结果 (1)负载抗菌药物的骨水泥第一天药物释放量最大,后逐渐持平,且释放时间较长,释放浓度较低;(2)截止到第7周盐酸万古霉素、亚胺培南西司他丁释放量分别只占总负载量的15%、25%;(3)盐酸万古霉素第1周后释放浓度低于最小有效抑菌浓度,亚胺培南西司他丁钠第7周后释放浓度低于最小有效抑菌浓度。结论载抗菌药物骨水泥存在长时间药物残留现象,是导致持续低于最小有效抑菌浓度的主要原因。此种现象不但对细菌起不到抑菌作用,而且是诱导细菌耐药性的危险因素。     

金银花水煎液及联合头孢他啶对铜绿假单胞菌生物膜的体外影响

目的　通过在体外复制铜绿假单胞菌 (Pseudomonasaeruginosa ,P .a)的生物膜 (biofilm ,BF)模型 ,研究金银花水煎液对BF的影响及其与头孢他啶 (ceftazidime ,CAZ)的协同杀菌效果。方法　选取临床分离呼吸道P .a ,采用LB(Luria Bertanimedium)肉汤系统复制体外BF模型 ,扫描电子显微镜(scanningelectronmicroscopy ,SEM)观察BF ,连续稀释法进行活菌计数 ,试管二倍稀释法测定药物的最低抑菌浓度 (MIC)。结果　 37℃培养 2 4h ,P .a即表现出对固体表面的黏附性 ,3d形成早期BF ,7d形成成熟BF。金银花组P .a在固体表面的黏附数明显少于空白对照组。 6 2 .5mg/ml的金银花可以抑制和破坏早期及成熟BF ,并增强CAZ对BF内P .a的抗菌活性。结论　金银花水煎液在体外能抑制P .a对固体表面的黏附能力及BF形成能力 ,并能破坏P .a已形成的BF ,增强CAZ对BF内铜绿假单胞菌的清除作用。     

舒巴坦钠与第三代头孢菌素头孢噻肟钠联合用药的体内外抗菌作用

采用琼脂二倍稀释法比较头孢噻肟钠单用与头孢噻肟钠与舒巴坦钠分别以 1∶1、2∶1、4∶1、8∶1和 1 6∶1配比对临床分离 4 37株致病菌 (其中产 β 内酰胺酶30 9株 ,非产酶 1 0 0株 ,厌氧菌 2 8株 )的体外抗菌活性。采有试管二倍稀释法、活菌计数法测定最低杀菌浓度MBC值。用琼脂二倍稀释法测定头孢噻肟钠舒巴坦钠 ( 4∶1 )在不同PH值 ( pH5 .0、pH7.0、pH9.0 )不同接种菌量 ( 1 0 5、1 0 7、1 0 9CFU/ml) ,不同血清浓度( 2 5、5 0、75 % )中的MIC值。采用小鼠实验性感染产酶金葡菌、大肠埃希菌、肺炎克雷伯菌和铜绿假单胞菌的体内保护…     

国产美洛培南的体外抗菌活性试验

目的:测定国产美洛培南(MEPM)和其它5种药物对136株临床分离菌的体外抗菌活性。方法:1)最小抑菌浓度(MIC)的测定:用琼脂二倍稀释法测定。     

氟喹诺酮类药物对肺炎克雷伯杆菌体外防耐药突变浓度的研究

目的:测定氟喹诺酮类药物(FQNs)对肺炎克雷伯杆菌的防耐药突变浓度(MPC),比较其防耐药突变能力,了解细菌对FQNs的耐药性。方法:肉汤法富集1010CFU.ml-1的菌液接种于不同浓度环丙沙星及加替沙星琼脂平皿上,采用琼脂二倍稀释法测定环丙沙星、加替沙星对临床分离肺炎克雷伯杆菌、ATCC700603及耐药突变体的最低抑菌浓度(MIC)、防耐药突变浓度(MPC)。结果:环丙沙星、加替沙星对肺炎克雷伯杆菌ATCC700603的MPC分别为8与1.6mg/mL,细菌耐药选择指数(MPC/MIC)分别为16与4mg/mL。2种氟喹诺酮类药物的第一步耐药突变体对筛选药物的MIC较ATCC700603提高4～24倍,第二步突变体又较第一步突变体高2～6倍。结论:加替沙星限制肺炎克雷伯杆菌耐药突变株选择的能力强于环丙沙星,肺炎克雷伯杆菌对FQNs耐药是累积性的。     

体外抑菌试验评价核糖体表达筛选的抗菌肽活性

目的观察体外无细胞核糖体表达系统筛选得到的、能与细菌膜结合的多肽的体外抑菌活性变化,初步评价该筛选系统的可行性。方法采用核糖体展示系统和细胞膜模型筛选可结合于细胞膜的多肽,对筛选的多肽进行结构预测分析。选择形成α-螺旋结构可能性大、溶解性尚可的多肽(C13)进行合成。利用改良的微量肉汤稀释法测定C13和硫酸庆大霉素对G (金黄色葡萄球菌)和G-(大肠杆菌、伤寒杆菌)细菌的抗菌活性——最小抑菌浓度(MIC)和最小杀菌浓度(MBC)。结果C13对试验细菌的MIC均为400mg/L,但在现有浓度范围对试验菌的MBC则未测得。结论体外无细胞核糖体表达系统筛选的抗菌肽C13具有一定的抑菌活性,表明利用人工膜模型和核糖体表达进行抗菌肽筛选的方法是可行的,但有效抗菌肽的筛选需进一步的抑菌试验证实。     

纳米银/脱细胞真皮基质的制备及抗菌效果评价

目的探讨含纳米银的脱细胞真皮基质的制备方法,以解决脱细胞真皮基质无抗菌活性的缺点;通过各种方法评价新型复合敷料的抗菌效果。方法通过倍比稀释法和基内接种法测定纳米银溶液的最低抑菌浓度和最低杀菌浓度;将脱细胞真皮基质浸渍在不同浓度的纳米银溶液中一定时间,制备出含不同浓度纳米银的复合敷料;通过Kirby-Baucer方法比较不同浓度浸渍的脱细胞真皮基质的抑菌效果。结果纳米银溶液对金黄色葡萄球菌的最低抑菌浓度是8mg/L,最低杀菌浓度是64mg/L;纳米银溶液对铜绿假单胞菌的最低抑菌浓度8mg/L,最低杀菌浓度是32mg/L。浸渍吸附法制备出含有不同浓度纳米银的脱细胞真皮基质。纳米银/脱细胞真皮基质对金黄色葡萄球菌和铜绿假单胞菌的抑菌效果优于纳米银医用抗菌敷料。结论纳米银/脱细胞真皮基质拥有良好的抗菌和杀菌效果,可望成为具有抗菌活性的生物敷料。     

苯妥英钠的抑菌活性

背景：苯妥英钠在创面愈合过程中的抑菌作用仍不明确。 目的：通过体外及动物实验观察苯妥英钠在创面愈合过程中是否具有抑菌作用。 方法：①体外实验：采用水解酪蛋白肉汤稀释法检测苯妥英钠的最低抑菌浓度、琼脂扩散法观察1 024 mg/L的苯妥英钠的体外抑菌活性。②动物实验：将30只SD大鼠随机等分为3组,在大鼠背侧脊柱旁设计一2 cm×3 cm矩形创面,分别用10,20 mg/cm²苯妥英钠糊剂或单纯凡士林纱布进行处理,创面均外加凡士林油纱及干纱包扎固定。隔日换药,于第4,8,12,16天进行创面表面细菌定量培养。 结果与结论：①水解酪蛋白肉汤稀释法结果：应用质控菌株、临床菌株进行试验,不同苯妥英钠浓度的试管中均呈现浑浊状态。②琼脂扩散法结果：应用质控菌株进行试验,未发现抑菌圈的形成。③实验动物创面细菌定量培养结果：应用10,20 mg/cm²苯妥英钠糊剂处理的创面细菌定量略低于单纯凡士林纱布处理的创面,但各组之间差异均无显著性意义(P > 0.05)。表明苯妥英钠尚无明确的体外及体内抑菌活性,对创面细菌的清除无明显作用。     

Antibacterial activity in blood cultures.

A total of 2,010 blood samples inoculated into tryptic soy broth were examined for antibacterial activity by means of a bioassay plate seeded with Bacillus subtilis spores. The size of the zone of inhibition on this plate was indicative of the degree of antibacterial activity. Current antibiotic therapy was confirmed by examination of chart records. Of the 2,010 blood cultures tested, 147 (7.3%) contained detectable levels of antibiotics; of these 147, 14 (9.5%) yielded growth of bacteria, and 133 (90.5%) remained negative. When the Antibiotic Removal Device (Marion Scientific, Div. Marion Laboratories, Inc., Kansas City, Mo.) was used, it eliminated the antibacterial activity but did not improve the recovery of bacteria from these cultures. Only bacteria resistant to the respective antibiotic were recovered from blood cultures that showed high levels of antibacterial activity (beta-lactam antibiotics, greater than 0.60 micrograms/ml; aminoglycosides, greater than 2 micrograms/ml; and tetracycline, greater than 4 micrograms/ml). Blood cultures showing low levels of antibacterial activity yielded both resistant and susceptible bacteria.     

Influence of growth conditions on the production of a bacteriocin by Lactococcus lactis subsp. lactis ST34BR, a strain isolated from barley beer

Bacteriocin ST34BR, a small polypeptide of 2.9 kDa produced by Lactococcus lactis subsp. lactis ST34BR, inhibits the growth of Enterococcus faecalis, Escherichia coli, Lactobacillus plantarum, Lactobacillus casei, Pseudomonas aeruginosa and Staphylococcus aureus. MRS broth, adjusted to pH 6.0 yielded 6,400 AU/ml, compared to 400 AU/ml recorded in BHI broth, M17 broth, 10% (w/v) soy milk, and 8% and 10% (w/v) molasses. At pH of 4.5 only 800 AU/ml was produced. Based on comparative studies in MRS broth, without organic nitrogen, supplemented with different combinations of tryptone, meat extract and yeast extract, tryptone was identified as the stimulating nitrogen compound. Growth in the presence of 20 g/l glucose, maltose, mannose or sucrose yielded bacteriocin levels of 6,400 AU/ml, whereas the same concentration of lactose and fructose yielded 3,200 AU/ml and 1,600 AU/ml, respectively. No difference in bacteriocin ST34BR activity was recorded in MRS broth supplemented with 2 g/l K2HPO4 and 2 g/l, 5 g/l, 10 g/l or 50 g/l KH2PO4. However, 20 g/l KH2PO4 increased bacteriocin ST34BR production to 12,800 AU/ml. Glycerol at 1g/l to 10 g/l in MRS broth reduced bacteriocin activity to 3,200 AU/ml, whilst 20 g/l and 50 g/l yielded only 1,600 AU/ml. The presence of cyanocobalamin, L-ascorbic acid, thiamine and DL-6,8-thioctic acid in MRS broth at 1.0 ppm, respectively, did not result in increased activity levels.     

Antimicrobial Activity of Extracts and Topical Products of the Stem Bark of Spathodea Campanulata for Wound Healing

The antibacterial activity of the aqueous, ethanol, methanol and petroleum ether Soxhlet extracts of sundried stem bark of Spathodea campanulata P. Beauv. (Bignoniaceae) was investigated by testing the extracts against B. subtilis, E. coli, P. aeruginosa and S. aureus. The minimum inhibitory concentration (MIC) of the methanol extract was determined against the four bacteria strains and C. albicans using the broth dilution method. Four topical products were prepared by incorporating the methanol extract of S. campanulata (20 % w/w) into aqueous cream, soft paraffin, emulsifying ointment and simple ointment bases and evaluated for their in vitro antimicrobial efficacy. The effect of storage time on the activity of the methanol extract of S. campanulata and S. campanulata extract incorporated in aqueous cream base was also investigated. The methanol and ethanol extracts showed good activity while the aqueous and petroleum ether extracts exhibited little activity. The methanol extract showed the best antibacterial activity. The MIC of the methanol extract of S. campanulata was: C. albicans (45 – 50 mg/ml), B. subtilis and E. coli (50 – 55 mg/ml), P. aeruginosa (60 – 65 mg/ml), S. aureus (145 – 150 mg/ml). Antimicrobial activity of S. campanulata in the topical bases was in the order: aqueous cream > emulsifying ointment > simple ointment > white soft paraffin. Antimicrobial activity of S. campanulata in aqueous cream decreased (p < 0.05) upon storage at room temperature for 6-months. The antifungal activity of the methanol extract of S. campanulata was reduced (p < 0.05) upon storage while antibacterial activity was largely unaffected.     

In situ synthesis of bacterial cellulose/copper nanoparticles composite membranes with long-term antibacterial property

Abstract

Bacterial cellulose (BC), with unique structure and properties, has attracted much attention in the biomedical field, especially in using as wound dressing. However, pure BC lacks the antimicrobial activity, which limits its application in wound healing. To solve this problem, copper nanoparticles (Cu NPs) loaded BC membranes were fabricated by using in situ chemical reduction method. The morphology and chemical composition of the composite membranes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The results showed that Cu NPs evenly distributed and anchored in the three-dimensional (3-D) nanofiber network of BC through physical bonding. Traces of Cu₂O were observed on the membranes probably because the Cu²⁺ was incompletely reduced. The Cu NPs loaded BC membranes showed efficient long-term antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) even after immersion in deionized water for up to 90?days. The composite membranes kept sustained release of copper ion, which may contribute to the long-term antibacterial activity. Furthermore, with controlled Cu concentration, BC/Cu membranes did not show obvious cytotoxicity to normal human dermal fibroblasts (NHDF). In all, the present results reveal that BC/Cu membranes with efficient antibacterial activity are promising to be used as wound dressings.     

Significant antibacterial activity and synergistic effects of camel lactoferrin with antibiotics against methicillin-resistant Staphylococcus aureus (MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) causes major healthcare problems in many countries, as it is present as several hospital- and community-associated strains. Hospital-associated MRSA is one of the most prevalent nosocomial pathogens throughout the world and infections caused by community-acquired MRSA are rising. This emphasizes the need for new and efficient anti-MRSA agents. We evaluated the antibacterial effects of camel lactoferrin (cLf) and human lactoferrin (hLf) alone and in combination with several antibiotics against MRSA. Antimicrobials were tested against MRSA and an S. aureus control strain by the agar disc diffusion method. The minimum inhibitory concentration (MIC) was determined for antimicrobials by the broth microdilution method. Synergy between cLf or hLf and antibiotics was examined by checkerboard and time-kill assays. The agar disc diffusion assay showed that MRSA growth was inhibited by cLf at 0.25–3 mg/ml and hLf at 1–3 mg/ml. cLf demonstrated 3 times higher inhibitory activity against MRSA than hLf in terms of MIC values (250 vs. 750 μg/ml, respectively). Biotinylated cLf was recognized by two membrane proteins of MRSA, 66–67 KDa. Combinations of cLf or hLf and oxacillin or vancomycin at sub-MIC levels enhanced in vitro antibacterial activity against MRSA compared with each agent alone.     

Studies on the preparation and antibacterial properties of quaternized polyethyleneimine

Quaternized polyethyleneimine (QPEI) was prepared via two types of macromolecular reactions, tertiary amination reaction and quaterization, and its chemical structure was characterized using infrared and UV spectroscopy. In this paper, the antibacterial properties of QPEI were mainly investigated by using Escherichia coli as model bacterium and with the colony count method. The effects of the cationic degree and pH value of the medium on the antibacterial properties of QPEI were examined. The antibacterial mechanism of QPEI was also explored using enzyme activity measurement methods, in which the enzyme activity of two enzymes, beta-D-galactosidase and TTC-dehydrogenase, were measured. The experiments show that QPEI possesses outstanding antibacterial activity because of combination effect of the antibacterial groups on the macromolecular chains. The antibacterial ratio reached 100% for bacterium suspensions of 10(9) CFU/ml with a polymer concentration of 15 mg/l for a contact time of 4 min. The cationic degree influences the antibacterial ability of QPEI greatly, and the higher the cationic degree, the stronger the antibacterial activity. The experimental data indicated that the pI of the E. coli protein is probably 4.5. When pH > 4.5, the antibacterial activity of QPEI increases with increasing pH, and when pH > 6 the antibacterial ratio reaches a maximum and remain nearly constant. The enzyme activity measurement results reveal that the antibacterial action of QPEI is based on a sterilization process. Similar to the small molecular quaternary ammonium salt, QPEI causes cell death by disrupting cell membranes and releasing the intracellular contents.     

<Emphasis Type="Italic">Terminalia bellirica</Emphasis> fruit extracts: in-vitro antibacterial activity against selected multidrug-resistant bacteria,radical scavenging activity and cytotoxicity study on BHK-21 cells

Background

Identification of novel sources for developing new antibiotics is imperative with the emergence of antibiotic resistant bacteria. The fruits of Terminalia bellirica (Gaertn) Roxb., widely used in traditional medicine, were evaluated for antibacterial activity against multidrug-resistant (MDR) bacteria, antioxidant activity and cytotoxicity.

Methods

Twelve solvent extracts of T. bellirica fruits were prepared by direct aqueous extraction and sequential extraction with dichloromethane, methanol and water using Soxhlet, bottle-shaker and ultrasound sonicator methods. Antibacterial activity of the extracts was tested against 16 strains MDR bacteria—methicillin-resistant Staphylococcus aureus (MRSA), extended spectrum β-lactamase (ESBL) producing Escherichia coli and MDR Acinetobacter spp., Klebsiella pneumoniae and Pseudomonas aeruginosa—and 4 control organisms, using the cut-well diffusion method. The minimum inhibitory concentration (MIC) was determined using an agar dilution method. The radical scavenging activity of six antibacterial extracts was screened against 2,2′-diphenyl-2-picrylhydrazyl (DPPH) and correlation was established between EC₅₀ (50% effective concentration) values and the total phenolic content (TPC). Cytotoxicity was determined for the most potent antibacterial extract on baby hamster kidney (BHK-21) cells by Tryphan Blue exclusion method. Statistical analysis was carried out by one-way analysis of variance at significant level p?<?0.05 using “SigmaPlot 10” and “R 3.2.0” software.

Results

All aqueous and methanol extracts displayed antibacterial activity (MIC 0.25–4?mg/mL) against all strains of MRSA, MDR Acinetobacter spp. and MDR P. aeruginosa. The sequential aqueous extracts (MIC, 4?mg/mL) inhibited ESBL producing-E. coli. None of the extracts exhibited activity against MDR K. pneumoniae (MIC >?5?mg/mL). The sequential methanol extract (Soxhlet) recorded high antibacterial activity and the highest DPPH radical scavenging activity (EC₅₀, 6.99?±?0.15?ppm) and TPC content (188.71?±?2.12 GAE mg/g).The IC₅₀ (50% inhibition concentration) values of the most potent antibacterial extract—the direct aqueous extract from reflux method—on BHK-21 cells were 2.62?±?0.06 and 1.45?±?0.08?mg/ml with 24 and 48?h exposure, respectively.

Conclusions

Results indicate that T. bellirica fruit is a potential source for developing broad-spectrum antibacterial drugs against MDR bacteria, which are non-toxic to mammalian cells and impart health benefits by high antioxidant activity.