Antibacterial activity of leaves extracts of Trifolium alexandrinum Linn,against pathogenic bacteria causing tropical diseases

Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.Methods:Non-polar and polar extracts of the leaves of T.alexandrinum i.e.,hexane,dichloromethane(DCM),ethyl acetate(EtOAc), methanol(MeOH) and aqueous(AQ) extracts at five different concentrations(1,2,5,10 and 15 mg/ mL) were prepared to evaluate their antibacterial value.NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.Results:Polar extracts demonstrated significant antibacterial activity against tested pathogens.EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens.While AQ plant extract inhibited the growth of sixteen of the test strains.EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.Conclusions:The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases.Since Egyptian clover is used as a fodder plant,it could be helpful in controlling various infectious diseases associated with cattle as well.

Antibacterial activity of plant extracts in different solvents against pathogenic bacteria: An in vitro experiment

Objective:To assess the antibacterial activity of 5 selected plants against 4 pathogenic bacteria.Methods:Three solvents with different polarities were used to extract antimicrobial agents from the plants via maceration technique.The agar-disc diffusion technique was adopted to primarily screen antibacterial activities.Broth-dilution assay was employed to determine the minimum inhibitory concentration(MIC)and the minimum bactericidal concentration(MBC).Results:Among all extracts,the ethanol extract of Piper betle Linn showed the highest antibacterial activity against Gram-positive and the negative bacteria.MIC and MBC of the ethanol extract of Piper betle Linn against Salmonella typhimurium were the same(1?562.50 mg/L);while it showed the highest MIC and MBC against Pseudomonas aeruginosa of 6?250 mg/L and 12?500 mg/L,respectively.Conclusions:Salmonella typhimurium is the most susceptible bacteria while Pseudomonas aeruginosa is the most resistant bacteria towards the ethanol extract of Piper betle Linn.Piper betle possesses compounds with potential antibacterial activity and might be useful as an alternative to control infectious diseases.

In vitro antibacterial potential of some Vitex species against human pathogenic bacteria

Objective:To study the antibacterial activity of the leaf methanol extracts of five different species of Vitex namely,Vilex altissima(V.allissima),Vitex diversifolia(V.diversifolia),Vitex negundo(V.negundo),Vitex peduncularis(V.peduncularis) and Vitex trifolia(V.trifolia). Methods:Antibacterial assay was carried out by using disc diffusion method,determination of minimum inhibitory concentrations(MIC) and minimum bactericidal concentrations(MBC) against five strains of Gram-positive and seven strains of Gram-negative human pathogenic bacterial strains.Results:The results of antibacterial activity of Vitex species showed that the extracts possessed a broad spectrum of antibacterial activity.The V.peduncularis possessed the highest activity against all the microorganisms screened.It produced a zone of inhibition ranged between (11.000±0.577) and(22.670±0.667) mm and the MIC values were from 62.5 to I 000.0μg/mL and the MBC values were from 125.0 to 2 000.0μg/mL.Conclusions:Based on the present study, V.peduncularis is recommended for the isolation of antibacterial molecule responsible for the activity against the tested human pathogenic bacterial strains.

Evaluation of antibacterial activity of bioactive compounds obtained from the seaweed Chondrococcus hornemanni on ichthyopathogenic bacteria affecting marine ornamental fish

Objective:To investigate antibacterial effects of extracts from the seaweed Chondrococcushornemanni(C.hornemanni)on bacterial pathogens of marine ornamental fish.Method:Methanol extract obtained from C.hornemanni showed a broad and high antibacterial activity against four fish pathogens including Providencia rettgeri,Aeromonas hydrophila,Vibrioalginoticus and Vibrio parahaemolyticus.The crude extract obtained from the dried seaweeds was fractionated and purified using column chromatography.Purified extracts were analyzed with Fourier transform infrared spectroscopy(FTIR)for identifying the functional groups.Phytoconstituents of the active fraction were further identified by means of gas chromatography and mass spectrometric(GC-MS)analysis.Result:The first fraction of the extracts showed effective inhibitory activity against Aeromonashydrophila and Vibrio parahaemolyticus at a concentration of 100μL.However,Vibrio alginolyticus and Providencia rettgeri had shown a moderately lesser inhibitory response to the extract.Conclusion:Hence,it is concluded that extracts of seaweed C.hornemanni,contain potential bioactive compounds with a considerable antibiotic activity.

Combined antibacterial and antibiofilm activity of phenyllactic acid and bacteriocin XJS01 against Shigella flexneri

This study investigated antibacterial and antibiofilm activity of the combined use of phenyllactic acid(PLA)and bacteriocin XJS01 against Shigella flexneri_14.The minimum inhibitory concentration(MIC)of PLA and XJS01 against S.flexneri_14 was 2.45 mg/mL and 18.75μg/mL,respectively.Growth and kill kinetics assays showed that the combined use of 1/2MIC PLA plus 1/2MIC XJS01 had a better activity against planktonic S.flexneri_14 compared to treatment with PLA and XJS01 used singly(1/2MIC and 2MIC).Cellular biochemical and morphological analysis revealed the remarkable ability of the combination in disrupting cell appearance and promoting deformation of planktonic S.flexneri_14 compared to single use.Moreover,S.flexneri_14 biofilm formation was inhibited and degraded by the combination,which showed a more remarkable antibiofilm activity than PLA and XJS01 when used singly.This study demonstrates the synergistic antibacterial activity of PLA and XJS01 against S.flexneri_14 in either planktonic or biofilm states in foods.

食药用菌对鸡病原细菌的抑菌活性测定

为了测试食用和药用真菌的抗菌活性,以鸡病原细菌沙门氏菌(Salmonella sp.)、大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)3种共6株为指示菌,筛选具有抑菌活性的食药用菌菌株。结果表明,共获得木层孔菌(Phellinus sp.)、鲍姆桑黄(Sanghuangporus baumii)、粗毛纤孔菌(Inonotus hispidus)、榆黄蘑(Pleurotus citrinopileat)、红平菇(Pleurotus salmoneo-stramineus)、糙皮侧耳(Pleurotus ostreatus)、大球盖菇(Stropharia rugosoannulata)、姬菇(Pleurotus cornucopiae)、真姬菇(Hypsizygus marmoreus)、猴头菇(Hericium erinaceus)、杏鲍菇(Pleurotus eryngii)和香菇(Lentinus edodes)12种16株具有抑菌活性的菌株,其中大球盖菇1号和杏鲍菇5号对6个病原细菌均有抑菌活性。添加蚕蛹粉后,可不同程度促进食药用菌菌丝体生长,并进一步提高菌株抑菌活性。

植物提取物对动物腹泻致病菌的抑菌作用及机制研究进展

植物提取物中多种生物活性物质可抑制畜禽肠道腹泻致病菌,作为饲料添加剂已广泛应用于畜禽生产过程中。本文综述了近年来国内外学者有关植物提取物的来源、抑菌活性和作用机制及其对畜禽细菌性腹泻疾病的治疗和预防机制的研究进展,以期为植物提取物防治畜禽腹泻病提供参考。

海草床盐生植物根际土壤可培养细菌多样性及抑菌活性研究

为探究海草床盐生植物根际土壤可培养细菌的新颖性和独特性及其代谢产物粗提物抑菌活性,该文采集防城港市珍珠湾和渔洲坪海草床9份盐生植物根际土壤进行研究,使用5种分离培养基,并采用稀释涂布法分离纯化可培养细菌。通过PCR扩增和16S rRNA测序进行菌种鉴定并对其进行多样性分析。采用滤纸片法筛选可培养细菌发酵粗提物对耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus)、表皮葡萄球菌(S.epidermidis)、金黄色葡萄球菌(S.aureus)和鲍曼不动杆菌(Acinetobacter baumannii)4种人类致病菌的抑制活性。结果表明:(1)从9份样品中共分离获得可培养细菌42株,隶属13个科14个属,包括链霉菌属、弧菌属、芽孢杆菌属、希瓦氏菌属、微杆菌属、短杆菌属、葡萄球菌属、鞘氨醇单胞菌属、罗思氏菌属、嗜冷杆菌属、假诺卡氏菌属、发光菌属、氟单胞菌属和志贺菌属,其中链霉菌属为优势菌属。(2)抑菌活性初筛结果显示,6株可培养细菌至少对2种以上人类致病菌有较强的抑制活性,其中1株来自弧菌属,1株来自罗思氏菌属,其余4株均来自链霉菌属。综上所述,防城港海域海草床盐生植物根际土壤微生物资源较新颖独特,链霉菌属细菌具有较强的抑菌活性,为开发新型抗生素提供了潜在菌种资源。

喹赛多对鱼类常见致病菌的试管内抑菌作用

用试管法测定了喹赛多对 4种鱼类常见致病菌的 8个菌株的抑菌活性。结果表明 ,喹赛多对几种供试菌均显示出较强的抑菌活性 ,对柱状嗜纤维菌的最小抑菌浓度 (MIC)为 0 .39μg/ml,嗜水气单胞菌为 0 .78μg /ml,鳗弧菌为 0 .78～ 1.5 6 μg/ml,迟缓爱德华氏菌为 0 .39～ 0 .78μg/ml。喹赛多的抑菌活性较盐酸土霉素、磺胺二甲嘧啶和盐酸金霉素弱 ,而较喹乙醇强。因此 。

黄花夹竹桃内生真菌抗病原细菌的初步研究

从植物黄花夹竹桃 (Thevetiaperuviana)的根、茎、叶、果实中分离出内生真菌 10 1株。以鼠伤寒沙门氏菌 (Salmonellatyphimurium)、肺炎链球菌 (Streptococcuspneumoniae)、乙型溶血链球菌 (Streptococcushemolyticus)、金黄色葡萄球菌 (Staphyllococcusaureus) 4种人类病原菌为指示菌 ,对其进行抑菌活性筛选 ,结果有 17株内生真菌对 1株或 1株以上人类病原菌有抑菌活性 ,其中平板抑菌圈直径大于 2 0mm的菌株有9株。具有抗菌活性的内生真菌分别来自木霉属 (Trichoderma)、曲霉属 (Aspergillus)等 9个属。

黄芩苷注射液体外抗菌作用实验研究

目的探讨黄芩苷注射液的体外抗菌活性。方法采用液体倍比稀释法,测定黄芩苷注射液对临床分离的161株常见病原菌的最低抑菌浓度(MIC)及最低杀菌浓度(MBC)。结果黄芩苷对临床常见病原菌的MIC范围为0.1～50mg/ml,MBC范围0.2～50mg/ml,对葡萄球菌MIC及MBC明显低于其他细菌,MIC范围0.1～6.3mg/ml,MBC范围0.2～12.5,MIC50、MIC90分别为0.4mg/ml、0.8mg/ml。结论黄芩苷注射液对多种病原菌有不同程度的抑菌作用,其中对葡萄球菌抗菌作用最强。

天然发酵茯砖茶微生物菌群及抗菌特性研究(英文)

对天然发酵茯砖茶的微生物菌群以及抗菌活性进行研究。微生物分离和鉴定结果表明:曲霉、青霉和散囊菌是天然发酵茯砖茶的主要微生物,其中散囊菌是真菌发酵过程中的优势菌种。发酵茶水提物的抑菌实验显示,茯砖茶的浸提物对一些食品致病菌有抑制作用,尤其是对一些芽孢形成菌如蜡状芽孢杆菌、枯草芽孢杆菌、产气荚膜梭菌和生孢梭菌具有抑制作用,抑菌能力随发酵时间的延长而增强。提示在茶叶真菌发酵过程中,能够产生抑制食品致病菌和腐败菌的代谢物质。

12种中草药抑菌作用研究

筛选了乌梅、金银花、蒲公英、紫草、牡丹皮等12种可用于食品的中草药,采用水提或醇提法制备中药提取液,以大肠杆菌、金黄色葡萄球菌、沙门氏菌、枯草芽孢杆菌这4种常见食源性致病菌为供试菌,采用牛津杯法进行体外抑菌实验。结果表明:艾叶、牡丹皮以及乌梅对4种供试菌均有较强的抑制作用,采用正交试验对上述3种中草药进行复配,分析得出最佳配比为乌梅∶艾叶∶牡丹皮=8∶1∶1,在最佳配比条件下,复配抑菌剂对4种受试菌的最低抑菌浓度分别为7.81 mg/mL、3.91 mg/mL、15.62 mg/mL、7.81 mg/mL。扫描电镜的结果表明:中草药复配抑菌剂能够破坏大肠埃希氏菌细胞结构,导致细胞内容物外泄,细胞死亡。

中药对鳗鲡病原菌的体外抑制作用

研究虎杖、石榴皮、大黄、黄芩、五倍子、黄连、冬凌草、独活、贯众、木贼草等10种中药材单用和五倍子、大黄、石榴皮、虎杖、黄芩、黄连两两联用(15种配方)对从养殖病鳗中分离得到的12株常见病原菌的抑菌作用。结果表明:中药单用对病原菌均有不同程度的抑制作用,其中,五倍子的抑菌作用最强,其次是大黄和石榴皮,木贼草的抑菌作用最差;中药联用呈现协同效应(FIC<1)的占68.3%,其中有显著协同效应(FIC≤0.5)的占26.0%,与中药单用相比,中药联用对大多数病原菌的抑制作用增强,且可大大减少单一中药的给药浓度。

普洱茶与绿茶提取物体外抑菌效应的研究

采用滤纸片扩散法分别研究不同浓度的普洱茶和绿茶提取物对李斯特氏菌(L.monocytogenes)、猪粪链球菌(S.faecalis)、大肠杆菌(E.coli)、鼠伤寒沙门氏菌(S.typhimurium)、金黄色葡萄球菌(S.aureus)和炭疽杆菌(B.anthracis)6株食源性微生物和致病菌的抑制效果及其最小抑菌浓度(MIC)。结果表明:普洱茶提取物在1%～7%(m/V)范围内对李斯特氏菌(L.monocytogenes)有较强的抑制作用,其MIC为0.07mg/ml,在5%～7%范围内对所有供试菌种均有抑制作用,对炭疽杆菌的抑制效果最好。绿茶提取物在1%～2%(m/V)范围内仅对李斯特氏菌(L.monocytogenes)有抑制作用,其MIC为0.09mg/ml,在3%时仅对炭疽杆菌(B.anthracis)无抑制作用,在4%～7%范围内对所有供试菌种都有抑制作用,对猪粪链球菌抑制效果最好。

连翘-4味汤散不同提取物对临床常见致病菌体外抗菌作用研究

目的:检测连翘-4味汤散不同溶剂提取物对临床常见致病菌体外抗菌作用。方法:采用琼脂平板稀释法、微孔板TTC法,以连翘-4味汤散不同溶剂(石油醚、氯仿、乙酸乙酯、无水乙醇、75%乙醇、水)提取物为实验药物,选用临床分离鉴定的,耐药现象较普遍的11种常见致病菌株为供试菌,检测实验药物的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)。结果:实验所用6种药物提取物,对金黄色葡萄球菌、表皮葡萄球菌、肠球菌、枯草芽胞杆菌、炭疽芽胞杆菌、大肠埃希菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌、阴沟杆菌、白假丝酵母菌等11种供试菌种,表现出了较为普遍的抑菌作用和一定的杀菌作用。结论:体外抗菌实验结果显示,实验药物表现出了较高的抗菌效能,连翘-4味汤散做为传统方剂,具有一定的药剂学和药理学研发价值。

化香果提取物体外抑菌活性研究

研究了化香果提取物对水产常见9种致病菌嗜水气单胞菌(Aeromonas hydrophila)、温和气单胞菌(Aeromonas sobria)、豚鼠气单胞菌(Aeromonas caviae)、维氏气单胞菌(Aeromonas veronii)、迟钝爱德华菌(Edwardsiella tarda)、副溶血弧菌(Vibrio parahaemolyticus)、鼠疫耶尔森氏菌(Yersinia pestis)、大肠杆菌(Escherichia coli)和金黄色葡萄球菌(Staphylococcus aureus)的抑菌活性。研究结果表明:化香果提取物对9种细菌均具有抑制作用,最小抑菌浓度为4.50 g/L。对每种细菌而言,抑菌效果随化香果提取物质量浓度的增加而增强,其中对大肠杆菌的抑制能力最强,IC_(50)值为0.035 g/L;金黄色葡萄球菌次之,IC_(50)值为0.053 g/L。对雌雄小鼠急性经口毒性试验结果表明化香果提取物对小鼠的急性经口半数致死量(LD_(50)值)分别为5 010和7 940 mg/kg体质量,表明化香果提取物属于实际无毒级。

水产养殖中使用的抗菌药物及细菌耐药性

目前 ,抗菌药物在水产养殖动物疾病防治中占有重要地位 ,然而 ,在水产养殖中使用抗菌药物也可产生一系列的副作用 ,例如细菌耐药性的产生和药物在鱼体和环境中的残留。本文就水产药物使用的历史、现状、适应症、副作用 ,耐药性的现状、来源、产生机制 ,耐药菌判定的标准 ,以及该领域的研究现状等问题进行综述与分析 。

载铜蒙脱石对水产病原菌的抗菌活性及其机理

通过阳离子交换反应,合成载铜蒙脱石,并研究它对水产病原菌的抗菌效果。X射线衍射分析显示:载铜反应前后,蒙脱石的(001)面网间距从原先的1.544 nm增加到了1.588 nm,表明铜是以水合阳离子或复合阳离子形式进入蒙脱石晶格层间位置。体外抗菌试验表明:蒙脱石未显抗菌活性,而载铜蒙脱石对所试水产病原菌均有很强的抑制和杀灭作用,它对嗜水气单胞菌、荧光假单胞菌、副溶血弧菌的最小抑菌浓度分别为150,150,75 mg/L,最小杀菌浓度分别为600,600,300 mg/L。载铜蒙脱石的抗菌能力是两方面因素的协同作用:一方面是其表面剩余正电荷能从水介质中大量吸附表面带负电荷的细菌;另一方面是矿物释放的铜离子对细菌的抑制和杀灭作用。

几种放线菌处理后对猪粪中主要病原菌和恶臭产生菌的影响研究

采用室内培养方法,研究评估了细黄链霉菌(Streptomyces microflavus)、抗生链霉菌(Streptomyces antibioticus)、灰色链霉菌(Streptomyces griseus)三种放线菌及其组合对猪粪中主要病原菌的影响,并对其体外的抑菌作用机理进行了初步探讨。结果表明,接菌处理能有效减少猪粪中的沙门氏菌(Salmonella spp.)、病原性大肠埃希氏菌(Escherichia coli O157)、空肠弯曲杆菌(Campylobacter spp.)、单核细胞增生李斯特氏菌(Listeria monocytogenos)的数量。与对照组相比,单独添加细黄链霉菌组后猪粪中空肠弯曲杆菌的数量从3.1×101cfu·g-1降至不可检测。放线菌胞内外活性混合物质的体外抗菌试验的结果显示,不管是单独处理还是几种放线菌的复合处理都对供试的大肠杆菌、梭菌、优杆菌、沙门氏菌、病原性大肠埃希氏菌、空肠弯曲杆菌、单核细胞增生李斯特氏菌表现出一定程度的抑制作用,在抑菌能力方面,单独添加细黄链霉菌的效果优于其他各组。