常用抗生素对鸭疫里默氏杆菌MIC最佳试验条件的确立

为了研究常用抗生素对临床分离到的鸭疫里默氏杆菌(riemerella anatipestifer,RA)的抑菌效果,试验首先绘制RA的生长曲线,确定其对数生长期,以对数生长期的细菌作为受试菌,测定6种常用抗生素对4株RA菌株在不同稀释度时的最小抑菌浓度(MIC),确定最佳接菌量,进而确定测定MIC的最佳时间。结果表明:新鲜培养的RA菌液的OD600值为0.8~1.2时,细菌达到对数生长期,菌落形成单位达到1×10^(11)~1×10^(12)cfu/m L。对数生长期细菌稀释至1×10^(-5)为最佳接菌量,将上述菌液接种到96孔板后,在37℃培养22~24 h为检测MIC的最佳时间。

Antimicrobial activities of the rhizome extract of Zingiber zerumbet Linn

Objective:To investigate antimicrobial effects of ethanolic extract of Zingiber zerumbet(Z.zerumbet)(L.)Smith and its chloroform and petroleum ether soluble fractions against pathogenic bacteria and fungi.Methods:The fresh rhizomes of Zingiber zerumbet were extracted in cold with ethanol(4.0 L)after concentration.The crude ethanol extract was fractionated by petroleum ether and chloroform to form a suspension of ethanol extract(15.0 g),petroleum ether fraction(6.6 g)and chloroform soluble fraction(5.0 g).The crude ethanol extract and its petroleum ether and chloroform fractions were evaluated for antibacterial and antifungal activity against thirteen pathogenic bacteria and three fungi by the disc diffusion method.Commercially available kanamycin(30μg/disc)was used as standard disc and blank discs impregnated with the respective solvents were used as negative control.Results:At a concentration of 400μg/disc,all the samples showed mild to moderate antibacterial and antifungal activity and produced the zone of inhibition ranging from 6 mm to 10 mm.Among the tested samples,the crude ethanol extract showed the highest activity against Vibrio parahemolyticus(V.parahemolyticus).The minimum inhibitory concentration(MIC)of the crude ethanol extract and its fractions were within the value of 128-256μg/mL against two Gram positive and four Gram negative bacteria and all the samples showed the lowest MIC value against V.parahemolyticus(128μg/mL).Conclusions:It can be concluded that,potent antibacterial and antifungal phytochemicals are present in ethanol extract of Z.zerumbet(L.).

Synergistic Effect between Fucoidan and Antibiotics against Clinic Methicillin-Resistant <i>Staphylococcus aureus</i>

Fucoidan is a sulfated polysaccharide that is primarily extracted from brown seaweeds which has been broadly studied in recent years due to its numerous biological properties, including anticoagulant, antithrombotic, antitumor, and antiviral activities. In this study, fucoidan was evaluated against clinic isolated methicillin-resistant Staphylococcus aureus (MRSA) 1 - 20, either alone or with antibiotics, via broth dilution method and checkerboard and time kill assay. Minimum inhibitory concentrations (MICs)/Minimum bactericidal concentrations (MBCs) values for the fucoidan against all the tested bacteria ranged between 64 - 512/256 - 2048 microg/mL, for ampicillin 32 - 1024/64 - 1024 microg/mL and for oxacillin 8 - 64/16 - 256 microg/mL respectively. Furthermore, the MIC and MBC were reduced to one half-eighth as a result of the combination of the fucoidan with antibiotics. 2 - 6 hours of treatment with 1/2 MIC of fucoidan with 1/2 MIC of antibiotics resulted from an increase of the rate of killing in units of CFU/mL to a greater degree than was observed with alone. These results suggest that fucoidan could be employed as a natural antibacterial agent against multi-drug bacteria.

全国1200例VVC致病菌的常见抗真菌药物MIC分析

目的了解全国外阴阴道假丝酵母菌病(VVC)致病菌株的分布及其对常见抗真菌药物的敏感性。方法复苏2015年全国45家医院于妇科门诊就诊的VVC患者的VVC菌株1200例。用科玛嘉假丝酵母菌显色培养基进行培养鉴定。参照美国临床实验室标准化协会(CLSI)M27-A3方案,测定其对氟康唑、克霉唑、咪康唑、伊曲康唑及制霉菌素5种抗真菌药物的最低抑菌浓度(MIC)值情况。结果(1)在培养的1200例VVC致病菌株中,白假丝酵母菌占81.17%(974/1200),非白假丝酵母菌占18.83%(226/1200)。在非白假丝酵母菌中,光滑假丝酵母菌最多,占13.25%(159/1200)。(2)白假丝酵母菌与非白假丝酵母菌的氟康唑、克霉唑、咪康唑、伊曲康唑及制霉菌素不同MIC值分布比较差异均有统计学意义(χ^(2)值分别为175.220、66.912、217.150、281.004、21.175,P<0.0001)。(3)对于克霉唑,白假丝酵母菌的MIC低值比例更低,而非白假丝酵母菌的MIC高值比例更高。对于咪康唑,非白假丝酵母菌的MIC低值比例更低,而白假丝酵母菌的MIC高值比例更高。(4)白假丝酵母菌和非白假丝酵母菌对氟康唑的耐药性均较高,MIC≥64μg/mL比例分别为73.41%和50.88%;而白假丝酵母菌和非白假丝酵母菌对于制霉菌素MIC低值比例均较高,MIC≤1μg/mL比例分别为79.67%和76.11%。(5)白假丝酵母菌对于伊曲康唑耐药性高于非白假丝酵母菌,MIC≥16μg/mL比例分别为43.12%和25.66%。结论VVC的主要致病菌仍是白假丝酵母菌,光滑假丝酵母菌已成为白假丝酵母菌以外的VVC第2大致病菌。白假丝酵母菌和非白假丝酵母菌对5种抗真菌药物的MIC值分布具有明显差异。全国VVC患者对氟康唑耐药性较高,白假丝酵母菌致VVC患者对克霉唑和制霉菌素敏感度较高,非白假丝酵母菌致VVC患者对咪康唑和制霉菌素的敏感度较高。

Antimicrobial Effects of Berries on Listeria monocytogenes

The purpose of this study was to first evaluate the antimicrobial effects of powder and extracts of berries (rose-hip, aronia, sea buckthorn and hawthorn) on the development of antibiotic-resistant L. monocitogenes. Listeria monocytogenes is considered one of the most important pathogens responsible for food-borne infection. Antimicrobial properties were evaluated using the standard Kirby-Bauer disk diffusion method. Bacterial inactivation networks were determined and compared, as well as the possibility of using powders and extracts of berries to control the risk of Listeria monocytogees infestation in the milk and dairy industry as well as in the meat industry. The effect of pH (4.78 - 4.43) and water activity (0.90 - 0.80) on the relationship between optical density (OD) at 600 nm and the plate count (CFU ml-1) was investigated for Listeria monocytogenes. It was determined Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) of berries for L. monocytogenes. The most relevant bacteriostatic and bactericidal effect on L. monocytogenes in the tested berries demonstrated sea buckthorn and rosehip.

Antimicrobial activity of PVP from an Antarctic bacterium, Janthinobacterium sp. Ant5-2, on multi-drug and methicillin resistant Staphylococcus aureus

Multiple drug resistant(MDR)and methicillin-resistant Staphylococcus aureus(MRSA)have become increasingly prevalent as a community acquired infection.As a result limited treatment options are available with conventional synthetic antibiotics.Bioprospecting natural products with potent antimicrobial activity show promise for developing new drugs against this pathogen.In this study,we have investigated the antimicrobial activity of a purple violet pigment(PVP)from an Antarctic bacterium,Janthinobacterium sp.Ant5-2 on 15 clinical MDR and MRSA strains.The colorimetric resazurin assay was employed to determine the minimum inhibitory concentration(MIC90)of PVP against MDR and MRSA.The MIC90 ranged between 1.57μg/mL and 3.13μg/mL,which are significantly lower than many antimicrobials tested from natural sources against this pathogen.The spectrophotometrically determined growth analysis and total microscopic counts using Live/dead®BacLight™fluorescent stain exhibited a steady decrease in viability of both MDR and MRSA cultures following treatment with PVP at the MIC levels.In silico predictive molecular docking study revealed that PVP could be a DNA-targeting minor groove binding antimicrobial compound.The continued development of novel antimicrobials derived from natural sources with the combination of a suite of conventional antibiotics could stem the rising pandemic of MDR and MRSA along with other deadly microbial pathogens.

Enhancing Accumulation and Penetration Efficiency of Next-Generation Antibiotics to Mitigate Antibiotic Resistance in Pseudomonas aeruginosa PAO1

This study explores the efficacy of advanced antibiotic compounds against P. aeruginosa, focusing on Antibiotic B, an enhanced derivative of Ceftriaxone. The study measured the intracellular uptake of Antibiotic B and introduced a novel adjuvant, Influximax, which augmented its antibacterial activity. Results showed a diminished potential for resistance emergence with Antibiotic B, particularly when used in combination with Influximax. The study suggests that optimizing antibiotic delivery into bacterial cells and leveraging syner-gistic adjuvant combinations can enhance drug resistance combat. .

氮杂尿苷对三株腐败菌抑菌活性的测定

目的:以二酮哌嗪为母核,对其结构修饰得到的30种化合物进行抑菌活性筛选,找到对大肠杆菌(E.coli)、腐败希瓦氏菌(Shewanella spp.)和铜绿假单胞菌(P.aeruginosa)抑菌效果理想的化合物。方法:首先采用紫外吸收光谱法定期测定放入光照振荡培养箱中菌悬液和营养肉汤的吸光度,得到三株腐败菌的生长曲线。其次采用纸片琼脂扩散法对药物的抑菌活性进行筛选,从30种化合物中筛出有抑菌效果的化合物。最后采用肉汤稀释法结合紫外分光光度计测定最低抑菌浓度(Minimum Inhibitory Concentration, MIC)。结果:氮杂尿苷对三株腐败菌的MIC均为3.42 mg/mL,且抑菌效果随着药物浓度的增大而增大。结论:氮杂尿苷对三种腐败菌具有较为显著的抑菌作用,这为后期防腐保鲜剂的研发提供了一定数据参考和理论支持。

大蒜蒜瓣中细菌多样性分析及抑菌剂筛选

微生物的生长会限制大蒜蒜瓣的贮藏期。通过分离纯化,结合菌落形态、菌体形态和PCR序列比对,分析大蒜蒜瓣中细菌多样性;测定抑菌圈直径、最小抑菌浓度和最小杀菌浓度,比较常用生物抑菌剂和化学防腐剂对大蒜蒜瓣中常见细菌的抑菌能力。结果表明,从大蒜蒜瓣中分离得到的菌株主要有水生拉恩菌、土生拉乌尔菌、表皮葡萄球菌、肠膜明串珠菌、乳酸明串珠菌、苏云金芽孢杆菌、成团泛菌、柠檬酸杆菌。生物抑菌剂肉桂醛和化学防腐剂双乙酸钠对4种指示菌(大肠杆菌、金黄色葡萄球菌、土生拉乌尔菌和水生拉恩菌)的抑菌效果最好,肉桂醛和双乙酸钠联用对大蒜蒜瓣中菌落总数的抑菌率达到98.4%,对大肠菌群的抑菌率达到100%。

基于cBD3的衍生肽对犬皮肤源多药耐药菌的抑菌活性

[目的]筛选犬皮肤源多药耐药菌,同时基于犬防御素设计衍生肽并探究其抗菌作用。[方法]通过K-B药敏纸片法对临床分离的菌株进行筛选,随后以犬β-防御素3(cBD3)的氨基酸序列为模板,采用氨基酸替换的方式对序列进行设计,选取优化肽cBD3-ABU进行化学合成,利用微量肉汤稀释法检测cBD3-ABU对多药耐药菌的抑菌活性。[结果]筛选获得8株犬皮肤源多药耐药菌;通过固相合成法获得纯度达95.61%的cBD3-ABU;cBD3对大肠杆菌、表皮葡萄球菌、伪中间型葡萄球菌和金黄色葡萄球菌的最小抑菌浓度分别为32、64、64、128μg/mL,高浓度cBD3-ABU对犬皮肤源大肠杆菌、表皮葡萄球菌、伪中间型葡萄球菌、金黄色葡萄球菌的抑菌率分别为96.02%、81.85%、87.25%、98.91%。[结论]cBD3-ABU在体外具有良好的抑菌活性,具有进一步开发为治疗性药物的潜力。

16种岭南特色道地药材对肺炎链球菌的抑菌作用研究

研究16种岭南特色道地药材对肺炎链球菌的体外抑菌活性。以肺炎链球菌为受试菌,采用24孔板培养法测定16种岭南特色道地药材醇提物的最低抑菌浓度(MIC)和最低杀菌浓度(MBC)。结果显示,16种岭南特色药材中有11种对肺炎链球菌有抑菌性,分别为:火炭母、桂枝、长萼堇菜、岗梅、广藿香、扁桃斑鸠菊、破布叶、一点红、狗肝菜、三桠苦、地胆草。其中,长萼堇菜、广藿香、扁桃斑鸠菊、狗肝菜、三桠苦、地胆草的醇提物表现出较强的抑菌活性。部分岭南特色道地药材的乙醇提取物对肺炎链球菌具有良好的抑菌作用。

酮康唑-甲基-β-环糊精包合物的表征及抑菌活性研究

[目的]为了提高低水溶性抗真菌药物酮康唑(ketoconazole,KCZ)的水溶性及抑菌活性,减少临床应用限制。[方法]采用饱和溶液法制备酮康唑-甲基-β-环糊精包合物,高效液相色谱法(HPLC)检测其溶解度,通过傅里叶变换红外光谱(IR)法对其结构进行表征,用纸片扩散法(K-B法)和最小抑菌浓度(MIC)方法对比检验酮康唑原药与酮康唑-甲基-β-环糊精包合物对白色假丝酵母菌的体外抗菌活性。[结果]通过甲基-β-环糊精包合,酮康唑在包合物中的水溶性比单一酮康唑增加了约2 941倍,通过傅里叶变换红外光谱(IR)法证实了有新物相形成。酮康唑原药的抑菌圈为(22.00±1.63) mm,酮康唑-甲基-β-环糊精包合物的抑菌圈则提升至(28.00±1.63) mm。最低抑菌浓度结果显示,酮康唑原药的最低抑菌浓度为(0.125±0.029)μg/mL,酮康唑-甲基-β-环糊精包合物的最低抑菌浓度为(0.062 5±0.015 0)μg/mL。[结论]酮康唑-甲基-β-环糊精包合物不仅没有破坏酮康唑原药对白色假丝酵母菌原有的抑菌能力,还提高了其抑菌效果。

泰宁等7种抗菌药物对临床常见致病菌抗菌活性的比较

用琼脂平板稀释法测定泰宁等７种抗菌药物对５种２１５株临床常见致病菌的最低抑菌浓度（ＭＩＣ），井统计敏感率。结果表明７种抗菌药物对大多数受试菌均显示较高的抗菌活性，其中泰宁的抗菌活性最强。金葡球菌、变形杆菌、大肠埃希氏菌、肺炎克雷白氏菌对泰宁的敏感率达９７．６～１００％；绿脓假单胞菌１７．０２％耐药，绿脓假单胞菌４．２６～１２．７７％和肺炎克雷白氏菌１株对泰宁和其他抗菌药物呈现部分交叉耐药性，而ＣＰＬＸ与其他抗菌药物对不同受试菌呈现２．３８～１９．０５％的交叉耐药率。该结果提示对其他β－内酰胺类抗菌药物耐药的致病引起的严重感染，可考虑选用泰宁，但ＣＰＬＸ的选用还应根据药敏试验决定。

苦豆子生物碱抗菌活性的测定

采用抑菌圈法测定了槐定碱、苦参碱、氧化苦参碱、氧化槐果碱、苦豆子总碱对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、番茄早疫、番茄灰霉和辣椒炭疽的抗菌活性。试验结果表明,5种生物碱对3种细菌生长均具有显著的抑制作用,其中槐定碱和苦参碱对大肠杆菌、枯草芽孢杆菌和番茄早疫的抗菌效果明显优于其他3种生物碱,苦参碱对大肠杆菌和枯草芽孢杆菌的最小抑菌浓度(MIC)达到12.5μg/mL。5种生物碱对3种真菌的抗菌效果弱于对3种细菌的抗菌效果,5种生物碱对3种真菌的MIC大于等于100μg/mL,氧化苦参碱、氧化槐果碱和苦豆子总碱对番茄灰霉菌的MIC均达400μg/mL。在质量浓度为100μg/mL时,5种生物碱中仅槐定碱表现出对辣椒炭疽菌的抑制作用。苦豆子总碱抗菌活性影响因素的试验结果表明,苦豆子总碱具有良好的热稳定性,在弱碱性条件下(pH8左右)具有更好的抑菌活性,在至少12 h内能够持续、稳定的对供试菌产生抑制作用。

瑞香狼毒根中抑菌活性成分的研究

研究了瑞香狼毒(Stellera chamaejasmeL.)对病原真菌石膏样毛癣菌的抑制作用,并对其活性成分进行了分离纯化.采用无水乙醇浸提瑞香狼毒根粉,并用不同极性溶剂进行依次萃取,结果表明乙酸乙酯萃取物具有较强的抑菌活性,其最低抑菌浓度(MIC)为312.5mg.L-1.然后采用硅胶柱对乙酸乙酯萃取物进行分段柱层析,并结合活性跟踪获得一高活性化合物,其最低抑菌浓度(MIC)为9.8mg.L-1.

仿刺参水溶性海参皂苷的分离制备及抗真菌活性的研究

利用海洋生物资源进行天然抗真菌新药的开发，从冻干海参加工废液中提取了水溶性海参皂苷，并对其抗真菌活性进行了研究。采用大孔吸附树脂法提取水溶性海参皂苷，经Libermann Burchard反应等对提取物的性质进行鉴定后，利用管碟法对所得提取物的抗菌活性进行了测定，并利用琼脂稀释法测定了所得水溶性海参皂苷对6株供试真菌的最低抑菌浓度（MIC）。提取物在Molish反应、沉淀反应和泡沫实验中均为阳性，说明提取物中确含有皂苷类成分；在Libermann Burchard反应中，液体的颜色处在红色与紫色之间，显示提取物可能是1种三萜类皂苷。水溶性海参皂苷对6株供试真菌均具有显著的抑制作用，且在浓度为0．5～4mg／mL的范围内，其抑菌活性与所用浓度之间呈明显的正相关性；在浓度为4mg／mL时，水溶性海参皂苷对6株供试真菌抑制活性的大小依次为裂殖酵母菌、啤酒酵母菌、白色念珠菌、葡萄炭疽病原菌、黄瓜枯萎病原菌和黑曲霉，海参皂苷对6株真菌的MIC值依次分别为0．002，0．016，0．063，0．063，0．125．0．250mg／mL。

泰宁等7种抗菌药物对临床常见致病菌抗菌活性的比较

采取琼脂平板稀释法测定了泰宁等7种抗菌药物对5种215株临床常见致病菌的最低抑菌浓度(MIC),并统计了敏感率。结果表明7种抗菌药物对大多数受试菌均显示了较高的抗菌活性,其中泰宁的抗菌活性最强,金葡菌、变形杆菌属、大肠埃希氏菌、肺炎克雷伯氏菌对泰宁的敏感率达97.6％～100％;17.02％的绿脓假单胞菌对泰宁耐药,2～6株绿脓假单胞菌和1株肺炎克雷伯氏菌对泰宁和其他抗菌药物呈现部分交叉耐药性。而CPFX与其他抗菌药物对不同受试菌呈现2.38％～19.05％的交叉耐药率。该结果提示对其他β-内酰胺类抗菌药物耐药的致病菌引起的严重感染,可首先考虑选用泰宁;但对CPFX还应根据药敏试验决定是否可以选用。

苍术挥发油的提取及其抑菌活性研究

采用水蒸气蒸馏法、微波萃取法和索氏提取法3种方法提取苍术挥发油。平板法涂布研究了3种苍术挥发油对3种细菌和4种真菌的最低抑菌浓度(MIC),滤纸片固相扩散法研究了苍术挥发油对供试菌体的抑菌活性。结果表明,3种方法提取的苍术挥发油对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、酵母、青霉、黑曲霉、黄曲霉的MIC分别为:水蒸气蒸馏法为5.00、150.00、150.00、5.00、5.00、5.00、20.00 mL/L;索氏提取法的为10.00、150.00、200.00、20.00、5.00、60.00、40.00 mL/L;微波萃取法的为10.00、150.00、150.00、20.00、20.00、20.00、20.00 mL/L。3种苍术挥发油对供试细菌和真菌都具有相当强的抑菌活性,且浓度越高效果越好。抑菌实验表明3种方法提取的苍术挥发油对金黄色葡萄球菌、酵母、青霉、黑曲霉、黄曲霉的抑菌圈直径都比对大肠杆菌、枯草芽孢杆菌的抑菌圈直径大。不同提取方法得到的苍术挥发油对同一种菌的最低抑制浓度和抑菌效果不相同,同一种方法提取的苍术挥发油对不同菌的最低抑制浓度和抑菌效果也不相同。

MTT法在抗真菌药敏实验中的应用

目的:研究MTT法在抗真菌药敏实验中的应用。方法:采用美国临床实验室标准化委员会(NCCLS)推荐方案测定两性霉素B和伊曲康唑对5种常见真菌(白色念珠菌、光滑念珠菌、季也蒙念珠菌、申克孢子丝菌和石膏样小孢子癣菌)的最低抑菌浓度(MIC),终点判定分别采用NC CLS推荐的直接观察法和MTT法,对两法进行比较。结果:MTT法与常规直接观察法进行MIC终点判定所得结果具有很好的一致性。MTT法测得的A值与接种菌量具有正相关性。两性霉素B与伊曲康唑对丝状真菌和念珠菌都具有很好的抑制作用,MTT法测得的A值随药物浓度的增加而显著降低。结论:MTT法较之常规直接观察法结果更为客观、准确,且可量化,因而可以很好的替代肉眼观察法来判定真菌药敏试验的终点。

解脲脲原体对氟喹诺酮类药物耐药性研究

目的探讨解脲脲原体对氟喹诺酮类药物的耐药状况与gyrA基因突变之间的关系。方法对鉴定确认的解脲脲原体临床分离株,采用微量肉汤稀释法检测其环丙沙星、氧氟沙星和左旋氧氟沙星的最小抑菌浓度(MIC),随机抽取28株菌株,PCR扩增gyrA基因并测序,采用Blast比对法分析临床菌株与标准菌株的序列差异。结果解脲脲原体的环丙沙星、氧氟沙星和左旋氧氟沙星MIC50分别为8,4和2 mg/L;MIC90分别为64,16和8 mg/L;在28株解脲脲原体菌株中,经测序分析发现gyrA基因3种突变形式:(1)101位丙氨酸改变为缬氨酸;(2)112位天冬氨酸改变为谷氨酸;(3)267位碱基T缺失。具有基因突变的菌株其MIC明显高于没有突变的菌株。结论江苏省部分地区解脲脲原体对第1、2代氟喹诺酮类药物耐药严重,此类药物不再适用于治疗解脲脲原体感染;解脲脲原体对氟喹诺酮类药物的耐药主要是由于gyrA基因突变导致相应氨基酸改变所介导。