中美动物源微生物耐药性监测对比研究

抗微生物药物在保障动物健康和食品安全方面发挥了重要作用,为了应对日益严峻的微生物耐药性问题,动物源微生物耐药性监测是应对微生物耐药性风险的重要防控策略。在“同一健康体系”工作框架下,中国和美国积极进行动物源微生物耐药性监测。本文通过对比研究中美动物源微生物耐药性系统的监测设计、监测对象和监测数据应用情况,结合我国畜牧兽医行业现状,立足我国动物源微生物耐药性监测客观需求,旨在为我国动物源微生物耐药性监测工作提供参考。     

Susceptibility pattern of bacterial isolates in equine ulcerative keratitis: Implications for empirical treatment at a university teaching hospital in Sydney

Corneal ulceration is a common ophthalmic condition in horses. It is frequently caused by trauma to the corneal surface, followed by secondary infection by commensal or pathogenic organisms including Streptococcus equi subspecies zooepidemicus, Pseudomonas aeruginosa and Staphylococcus spp. Emerging antimicrobial resistance amongst these organisms has raised the need for appropriate antimicrobial therapy selection, to optimise treatment efficacy while minimising further antimicrobial resistance. Medical records of 38 horses presented at the University Veterinary Teaching Hospital Camden for ulcerative keratitis between 2010 and 2020 were reviewed to identify those with positive bacterial cultures and antimicrobial susceptibility profiles (13/38). Common susceptibility patterns were identified and used to guide the empirical treatment of equine bacterial corneal ulcers. Pseudomonas spp. (64.3%), Streptococcus equi subspecies zooepidemicus (14.3%) and Actinobacillus spp. (14.3%) were most commonly identified. Susceptibility to amikacin, gentamicin and ciprofloxacin was observed in 100%, 66.7% and 85.7% Pseudomonas spp. isolates respectively. Resistance to polymyxin B and neomycin occurred in 85.7% and 71.4% of Pseudomonas spp., respectively. All Streptococcus equi subspecies zooepidemicus organisms in this study were susceptible to ceftiofur, cephalexin, penicillin and ampicillin, while they were all resistant to gentamicin, neomycin, enrofloxacin and marbofloxacin. Predominating in this study, Pseudomonas spp. maintained overall aminoglycoside susceptibility despite some emerging resistance, and good fluoroquinolone susceptibility. High resistance to Polymyxin B could have arisen from its common use as first-line therapy for bacterial corneal ulcers. Although further research is required, these new findings about predominant bacteria in equine corneal ulceration in the Camden region and their antimicrobial susceptibility patterns can be used to guide the empirical treatment of bacterial corneal ulcers in horses.     

添加纳米粒子的塑料包装材料在杨梅保鲜中的作用

纳米技术应用在杨梅保鲜包装上是一个新的尝试,它采用了交互性实验设计方案,将银纳米材料添加进塑料制成包装材料,可观测其保鲜效果.结果表明,纳米塑料包装材料和纳米奇冰石在提高杨梅好果率和延长货架期方面有正面效果;同时,在抑制VC分解方面具有一定的作用.     

抗菌肽的作用机制、应用及改良策略

抗菌肽是一类具有抑菌活性的多肽物质,具有多种优点,包括安全无毒、抗菌谱广、稳定性好、杀菌浓度低、分子质量小、致敏性弱等,成为了生物领域的研究热点之一。本文介绍了抗菌肽的研究现状以及应用情况,分析了目前抗菌肽存在的问题及改良策略,并对应用前景进行了展望。     

皂荚提取物对植物病原菌的抑制作用

 豆科植物皂荚是一种传统药用植物,为我国特有种。本文在室内测定了皂荚叶和棘刺乙醇提取物对枯草芽孢杆菌、胡萝卜软腐欧文氏杆菌、番茄疮痂病菌、番茄灰霉病菌、番茄叶霉病菌、棉花枯萎病菌、瓜果腐霉的抑制作用。叶提取物未检测出抗菌活性。棘刺提取物对枯草芽孢杆菌和番茄疮痂病菌都表现出一定的抗菌活性,最低抑菌浓度(MIC)分别为2.5 mg/mL和10 mg/mL。棘刺乙醇提取物在浓度为1 mg/mL时,对4种植物病原真菌的生长都表现出抑制活性,其中对瓜果腐霉生长的抑制率为28.4%。将棘刺乙醇提取物分为石油醚等5个极性不同的萃取部分,其中乙酸乙酯部分对枯草芽孢杆菌、番茄疮痂病菌、欧文氏杆菌都具有明显的抑制作用,且活性强于其它的极性段,对枯草芽孢杆菌和番茄疮痂病菌的MIC分别为1.25 mg/mL和5 mg/mL。乙酸乙酯部分对瓜果腐霉和棉花枯萎病菌的生长也有较强的抑制作用,在1mg/mL时抑制率分别为45.8%和23.9%。研究结果表明,皂英抗菌活性成分主要存在于棘刺中的乙酸乙酯极性段和正丁醇极性段中。     

Evaluation of treatment and prophylaxis with nitrofurans and comparison with alternative antimicrobial agents in experimental Salmonella enterica Serovar enteritidis infection in chicks

The ability of the nitrofuran antimicrobial agents furazolidone and furaltadone to prevent, reduce or eliminate Salmonella enterica serovar enteritidis PT4 infection in artificially challenged day-old chicks was evaluated. Treating the birds with the nitrofurans failed to eliminate established infections with either furazolidone-resistant (Fz^R) or furazolidone-sensitive (Fz^S) strains. Simultaneous administration of the nitrofurans to day-old chicks challenged with Fz^S failed to prevent infection but reduced colonization significantly (p<0.05) compared to unmedicated controls. No reduction of colonization occurred with Fz^R. Challenging birds with Fz^S and simultaneous dosing with nitrofurans for 1 week, followed by a second week of continued treatment, resulted in an increase in the level of colonization in the second week rather than a decrease. Dosing with the nitrofurans (200 ppm) for 1 week prior to challenge with Fz and continued medication for a further week prevented colonization of the caecum, liver and spleen. However, cessation of dosing at the time of challenge with salmonella resulted in colonization. Chloramphenicol and tetracycline at concentrations of 200 ppm were both independently capable of preventing colonization by salmonella. Sulphadiazine initially reduced colonization but failed to eliminate the infection. Only when furazolidone was combined with chloramphenicol or when sulphadiazine was combined with trimethoprim, and the combined drugs were administered concurrently with the challenge, was colonization prevented.     

猪源致病性沙门氏菌耐药基因的分析

采用平板稀释法，选用氨基糖苷类、四环素类、磺胺类和氯霉素类4大类抗生素的11种药物，对30株猪源致病性沙门氏菌进行了药敏试验，结果有28株菌（93．3％）至少对一种药物有耐药性；对四环素、强力霉素、磺胺甲基异口恶唑、复方新诺明、链霉素、卡那霉索和氯霉素有耐药性的菌株较普遍，在所有菌株中占比例分别为83．3％、80％、80％、76．7％、60％、56．7％和56．7％。设计了25对引物，对耐药基因进行了扩增及序列测定，结果扩增到13种耐药基因，与GenBank中的相应基因有很高的同源性（≥98．1％）。30株猪源致病性沙门氏菌中至少含有一种耐药基因的菌株有28株（93．3％），sul1、aph（3′）-Ⅱa、tetC、Catl、tetA和aadAl耐药基因较为普遍，检出率分别为76．7％、60％、60％、43．3％、40％和36．7％。药敏试验结果与耐药基因检测结果有很高的一致性（≥88％）。     

乳中黄嘌呤氧化还原酶的研究进展

黄嘌呤氧化还原酶属于含钼脱氢酶黄素蛋白家族，是组成乳脂肪球膜的主要蛋白，通过硫酸胺分级沉淀和DEAE-Sepharose柱可从乳脂肪球膜中纯化。XOR作为乳脂肪球膜的膜结合蛋白，在脂肪滴的包裹和分泌中起到重要的结构作用，并且在肠道能够起到一定的抗菌作用。