优化提取裸花紫珠总黄酮含量及对表皮伤口易感染菌抑菌性的研究

为了选出裸花紫珠总黄酮提取的最优方法,比较了ASE、超声、微波萃取和多功能浓缩4种提取方法在裸花紫珠总黄酮提取率上的差异,并利用微孔刃天青法测定总黄酮对表皮易感染菌的MIC值。结果发现ASE法总黄酮提取率最高,约为1.26%,其次为超声和微波萃取法,总黄酮提取率分别约为1.03%和0.98%,多功能浓缩法提取率最低,约为0.36%,且耗时最长。而且研究发现,ASE的MIC值最低。最终得出ASE提取效率最高,且提取物有较好的抑菌性,是裸花紫珠总黄酮提取的最优方法。     

In vitro susceptibility of Brachyspira hyodysenteriae to organic acids and essential oil components

The antibacterial potential of organic acids and essential oil components against Brachyspira hyodysenteriae, the causative pathogen of swine dysentery, was evaluated. Minimum inhibitory concentrations (MIC) of 15 compounds were determined at pH 7.2 and pH 6.0, using a broth microdilution assay. In addition, possible synergism was determined. MIC values for the three tested strains were similar. For organic acids, MIC values at pH 6.0 were lower than at pH 7.2. B. hyodysenteriae was most sensitive to cinnamaldehyde and lauric acid, with MIC values <1.5 mM. Most antibacterial effects of binary combinations were additive, however, for thymol and carvacrol, synergism could be observed. In vitro results demonstrate the antibacterial action of certain essential oil components and organic acids against B. hyodysenteriae.     

豫北地区临床分离鸡大肠杆菌的体外抑菌作用测定

为了有效地治疗鸡大肠杆菌病,采用微量倍比稀释方法测定了17种抗菌药物对临床分离的豫北地区15株鸡大肠杆菌的体外最小抑菌浓度（MIC）,并根据其MIC及MIC范围（MICRange）使用SPSS 13.0中Probit过程计算出17种抗菌药物的MIC50和MIC90。结果表明：多粘菌素B的抑菌作用最强,MIC50、MIC90分别为0.11、0.87μg/mL;加替沙星的抑菌作用次之,MIC50、MIC90分别为2.53、3.88μg/mL,其它3种药物恩诺沙星、左氧氟沙星、环丙沙星的抑菌作用相当,但不及加替沙星,MIC50、MIC90分别为10.11-11.79μg/mL、15.16-21.13μg/mL;多西环素和阿莫西林等12种抗菌药物的抑菌作用较小,MIC50、MIC90分别为18.53-388.50μg/mL和30.59-713.42μg/mL。     

阿莫西林和硫酸粘菌素对猪鸡大肠杆菌和沙门氏菌的体外联合抗菌作用

探讨了阿莫西林与硫酸粘菌素对猪鸡的大肠杆菌和沙门氏菌的联合抗菌效果。采用微量稀释法分别测定阿莫西林与硫酸粘菌素单药对大肠杆菌和沙门氏菌的最低抑菌浓度（MIC）,采用棋盘稀释法测定阿莫西林与硫酸粘菌素联用对大肠杆菌和沙门氏菌的MIC并计算联合指数（FIC）。试验结果显示,对14株试验菌株体外联合抗菌呈协同与相加作用的占78.6%,呈无关作用的占21.4%,无拮抗作用,表明阿莫西林和硫酸粘菌素可联合应用于治疗猪鸡大肠杆菌和沙门氏菌感染。     

复方恩诺沙星可溶性粉对畜禽主要致病菌的体外抑菌效果

采用纸片扩散法(K-B法)测定复方恩诺沙星可溶性粉对畜禽主要致病菌的敏感性,采用试管倍比稀释法测定复方恩诺沙星可溶性粉对畜禽主要致病菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)。结果表明,病原性大肠埃希菌、绿脓杆菌、金黄色葡萄球菌、鸡巴氏杆菌、猪巴氏杆菌和链球菌对复方恩诺沙星可溶性粉敏感,复方恩诺沙星可溶性粉对畜禽主要致病菌的MIC为0.0279μg/mL~3.575μg/mL,MBC为0.055μg/mL~7.11μg/mL。     

盐酸小檗碱与左氧氟沙星联合抑制MRSA及其机制研究

养殖场抗生素滥用造成多种耐药性细菌的产生,从奶肉类制品中分离出耐甲氧西林金黄色葡萄球菌（MRSA）的案例逐年增长,对养殖业食品安全造成巨大威胁。本研究筛选出与左氧氟沙星具有联合抑制MRSA效果的天然产物盐酸小檗碱（BBR）,探究BBR与其对MRSA的协同抑菌效果和联合抑菌机制。结果表明,BBR能有效抑制MRSA生长,提高MRSA对左氧氟沙星的敏感度,两者联用后,MRSA对左氧氟沙星的MIC降为之前的1/16。协同作用机制主要为上调ribA及下调mec A和msc L表达水平,破坏细胞壁、增加细胞膜的通透性,从而达到协同抑菌的目的。本研究有助于降低畜牧养殖中抗生素的使用,为提高肉奶类食品安全奠定基础。     

Epidemiological Cut-off Values (ECOFFs) of Salmonella from Chicken Intestinal Tract for Three Animal-specific Antibiotics

In order to establish epidemiological cut-off values (ECOFFs) of Salmonella for three animal-specific antibiotics (florfenicol,apramycin and danofloxacin) in Guangdong province.A total of 166 strains of Salmonella isolates from chicken intestinal tract from veterinary clinics and farms in Guangdong province in 2017 were recruited in this study,the minimum inhibitory concentrations (MIC) of florfenicol,apramycin and danofloxacin were determined in triplicate for each bacterial strain using the agar dilution method on Mueller-Hinton agar plates according to the CLSI reference method (CLSI-M100-S26).ECOFFs were calculated for the MIC data sets by application of nonlinear regression analysis,NRI(normalized resistance interpretation) and ECOFFinder software.MIC distribution of florfenicol,apramycin and danofloxacin against Salmonella from 2 to >512,4 to >512 and 0.015 to 64 μg/mL,respectively.MIC₅₀ and MIC₉₀ for apramycin,florfenicol and danofloxacin were 256 and >512,16 and >512,0.5 and 16 μg/mL,respectively.MIC distribution of apramycin and florfenicol presented obvious unimodal shape,while that of danofloxacin was a discontinuous multi-peak.The ECOFFs of florfenicol,apramycin and danofloxacin were recommended to be 16,16 and 0.125 μg/mL,respectively.In present study,the ECOFFs of Salmonella from chicken intestinal tract for apramycin,florfenicol and danofloxacin were determined,which provided scientific basis for resistance surveillance.     

水溶性甲壳胺体外抑菌活性的试验研究

用二倍稀释法测定 6种甲壳胺样品的最低抑菌浓度 (MIC) ,并根据MIC制作含有甲壳胺的普通琼脂培养基和药敏试纸片。结果表明 :编号为 1 #、 3 #、 4 #、 6 #甲壳胺在一定浓度时对大肠杆菌、金黄色葡萄球菌、沙门氏菌、巴氏杆菌均有不同的抑制作用 ;2 #、 5 #在试验所用浓度下抑菌效果不明显。用与MIC相同浓度配制的甲壳胺琼脂的抑菌作用与试管MIC法相同 ,而甲壳胺试纸片则需要 8个MIC才有抑菌作用。     

二氢杨梅树皮素的抑菌作用研究

采用二倍稀释法对显齿蛇葡萄中主要成分二氢杨梅树皮素的体外抗菌活性进行测定，并与相同实验条件下盐酸黄连素的抑菌活性相比较；同时还研究了培养基不同pH及药物pH对二氢杨梅树皮素抑菌效果的影响。结果表明：二氢杨梅树皮素对动物的7种致病菌株均有较强的抑菌作用，与盐酸黄连素的抑菌效果相当或略强。培养基在酸性、碱性条件下，二氢杨梅树皮素的抑菌作用显著增强，酸性二氢杨梅树皮素和碱性二氢杨梅树皮素的抑菌效果比中性二氢杨梅树皮素的抑菌效果显著增强。