金黄色葡萄球耐药性的研究及其防制策略

金黄色葡萄球菌是临床上最常见的致病菌之一,可引起鼻腔、口腔黏膜及皮肤和上皮组织的感染,严重的可导致肺炎、败血症甚至死亡。现今金黄色葡萄球菌已经对大部分常用抗生素有耐药性,作者综述了金黄葡萄球菌对抗生素的耐药发展史、耐药机制及对其使用的治疗策略。     

γ-干扰素对金黄色葡萄球菌性临床型乳房炎的疗效研究

本试验选取32只3~4 kg健康泌乳家兔,通过人工造模的方法诱发其乳腺发炎,建立金黄色葡萄球菌性临床型乳腺炎模型。然后随机分为A(γ-干扰素)、B(乳酸环丙沙星)、C(γ-干扰素和乳酸环丙沙星)、D (生理盐水)4个治疗组,每组8只,于造模后6、18 h各投药一次。各组分别在造模前1 h和造模后4、12、24、36、48、72 h采集血液0.5 mL、血清1 mL,进行白细胞总数、血清钙离子含量和炎性细胞因子测定(ELISA),研究其治疗效果。结果显示:①外周血白细胞总数组间对比,A、B组在造模后12~48 h内极显著高于C组(P<0.01),72 h时显著高于C组(P<0.05),但两组间无显著差异(P>0.05);D组在造模后12~72 h内均极显著高于其他3组(P<0.01)。②血清钙离子含量组间对比,A、B组在造模后12~48 h内极显著低于C组(P<0.01),72 h时显著低于C组(P<0.05),但两组间差异不显著(P>0.05);D组在造模后12~72 h内均极显著低于其他3组(P<0.01)。③血清中TNF-α和IL-6含量组间对比,A、B组在与C组造模后12~24 h内差异显著(P<0.05),36~48 h内差异极显著(P<0.01),72 h后差异显著(P<0.05),A、B两组间无显著差异(P>0.05);D组在造模后12~72 h内均极显著高于其他3组(P<0.01)。结果表明,γ-干扰素配合乳酸环丙沙星治疗金黄色葡萄球菌性临床型乳房炎具有一定的协同作用。     

山羊金黄色葡萄球菌健康带菌情况的调查及耐药性分析

金黄色葡萄球菌是引起人和动物感染及食物中毒的重要病原体之一。为了解四川省山羊金黄色葡萄球菌的健康带菌情况及其耐药性,采集了省内4个养殖场共32只山羊的鼻腔棉拭子样本,进行金黄色葡萄球菌的分离、鉴定及药敏试验。共从11只羊的鼻腔棉拭子样本中分离出金黄色葡萄球菌,检出率为34.4％。对临床分离株进行了苯唑西林、头孢西丁、万古霉素等11种抗菌药物的药敏试验,结果表明,分离株对氨苄西林的耐药率为72.7％,对其它抗菌药物没有耐药性,未发现耐甲氧西林金黄色葡萄球菌（MRSA）。本研究结果表明,四川地区山羊的金黄色葡萄球菌的带菌情况较普遍,因此,应该规范屠宰过程的卫生操作,并进行严格监控,减少金黄色葡萄球菌的污染。     

金黄色葡萄球菌烈性噬菌体的分离鉴定和最佳保存方法研究

基于细菌rRNA区域序列的PCR技术,通过设计特异性引物从奶样中快速、准确地鉴定奶牛乳房炎主要致病菌金黄色葡萄球菌。采用金黄色葡萄球菌与挤奶前从奶牛乳房上洗刷下来的污水经过3次富集的方法,通过双层琼脂平板法,分离纯化得到了强裂解性的奶牛乳房炎主要致病菌金黄色葡萄球菌的噬菌体。本试验分离的是可收缩尾的噬菌体,其头部为二十面体,约50 nm×62.5 nm,尾部长约187.5 nm,尾宽约37.5 nm,有尾鞘、基板等结构。纯化后在双层琼脂平板上形成的噬菌斑大而整齐,边缘光滑,透明,直径约2 mm,具有明显的强裂解性噬菌体特性,通过测定,该噬菌体的最佳感染复数为0.01,效价大于10⁹ PFU/mL。对噬菌体的不同保存方法进行比较,结果表明,将噬菌体置于-80 ℃加入7% DMSO冷藏是较好的保存方法。     

泰安郊区肉鸡金黄色葡萄球菌耐药性分析

对肉鸡金黄色葡萄球菌耐药性进行分析,结果表明,该菌株对中药黄连和抗生素头孢唑啉、替米考星药敏纸片表现为极度敏感;对中药黄芩、大青叶和抗生素恩诺沙星、氯雾素、卡那霉素、痢特灵药敏纸片高度敏感;对链霉素和环丙沙星药敏纸片中度敏感;对板蓝根、四环素、庆大霉素以及白头翁、红霉素、青霉素等表现为低度敏感或耐药。     

Comparison of bioactive compounds content, free radical scavenging and anti-acne inducing bacteria activities of extracts from the mangosteen fruit rind at two stages of maturity

Contents of bioactive components, free radical scavenging and anti-acne producing bacteria activities of young and mature fruit rind extracts of mangosteen were compared. The young fruit rind extract contained significantly higher contents of phenolics and tannins and promoted higher free radical scavenging activity than the mature fruit rind extract, while the later extract contained higher contents of flavonoids and α-mangostin xanthone and gave higher anti-acne producing bacteria activity than the young fruit rind extract. Thus, the young and mature stages of mangosteen fruit rind should be beneficial for further development of antioxidant and anti-acne pharmaceutical preparations, respectively.     

金黄色葡萄球菌FnBP配体结合区基因的克隆及其原核表达(英文)

[Objective] The study aimed to clone the FnBP ligand binding gene of Staphylococcus aureus and run prokaryotic expression by constructing a prokaryotic expression vector. [Method] The gene encoding FnBP ligand binding gene was amplified from S.aureus chromosomal DNA by PCR technique. After T-A cloning, plasmid pMD18- FnBP was constructed. pMD18- FnBP and pET28a(+)were digested by BamH Ⅰ and EcoR Ⅰ double enzymes, then the purified FnBP ligand binding gene was subcloned into the expression vector pET28a(+), and the prokaryotic expression vector pET28a-FnBP was thus constructed. The constructed plasmid pET28a-FnBP was transformed into Escherichia coli BL21(DE3) competent cells. The bacterium was induced by IPTG and the expressed products were analyzed by SDS-PAGE and Western blot. [Result] The gene fragment with the length of 370 bp was amplified by PCR approach. One approximately 30 kD exogenous protein was observed in SDS-PAGE analysis. Western blot analysis indicates the protein has antigenicity of S.aureus. [Conclusion] The FnBP ligand binding gene of S.aureus was successfully cloned and expressed in prokaryotic cells.     

金黄色葡萄球菌粘附素Fnbp A功能区基因的克隆和原核表达

【目的】克隆和表达奶牛乳腺炎金黄色葡萄球菌纤连蛋白连接蛋白A(Fnbp A)的功能基因。【方法】采集奶牛急性乳腺炎乳样,分离金黄色葡萄球菌,提取其DNA作为模板,利用设计合成的特异性引物,对金黄色葡萄球菌进行FnbpA功能基因的PCR扩增。回收目的基因并连接到T载体,鉴定后进行测序,然后将FnbpA基因连接到pET-32a(+)质粒中,经鉴定后转化大肠杆菌BL21感受态细胞,IPTG诱导后采用SDS-PAGE分析蛋白质的表达情况。【结果】PCR产物经电泳成像,仅金黄色葡萄球菌在1.7 kb处出现特异性条带,测序发现其与GenBank公布的FnbpA序列的同源性为98%;蛋白诱导表达SDS-PAGE分析发现,在80 ku处出现特异性条带。【结论】试验成功地克隆到FnbpA基因,并在大肠杆菌中获得高效表达,蛋白量为33.4%,为进一步研究金黄色葡萄球菌粘附素基因工程疫苗奠定了基础。     

金黄色葡萄球菌诱发小鼠实验性乳腺炎研究

为建立小鼠乳腺炎模型,本试验选用35只泌乳期BALB/C雌鼠随机分成7组,其中6组于产后8~10 d分别用灭菌生理盐水和不同浓度的金黄色葡萄球菌悬液50μL经乳头管注入到小鼠的第4对(腹部)乳腺内,观察小鼠体温、组织病理学、间质宽度、腺泡壁厚度的变化以及乳腺组织中CFU、TNF-α和IFN-γ含量变化。结果表明:试验组小鼠体温呈现先下降后上升的趋势,以T3组明显;组织病理学显示乳腺上皮脱落,腺泡腔内大量炎性细胞浸润,以嗜中性粒细胞为主,腺泡内空泡减少,间隔增宽,炎症明显。而随着金黄色葡萄球菌用量的加大,乳腺组织的炎症程度加剧。T3组间质宽度高于其他组。与对照组相比,T3组小鼠乳腺组织中腺泡壁厚度、CFU、TNF-α及IFN-γ含量极显著升高(P<0.01)。结果表明金黄色葡萄球菌诱发小鼠试验性乳腺炎模型与炎症的免疫病理过程和炎性反应一致,可用作病理模型使用。     

Methanol extract of Black soldier fly (Hermetia illucens) prepupae against Aeromonas and Staphylococcus aureus bacteria in vitro and in silico

Background:Staphylococcus and Aeromonas bacteria are pathogens in humans and animals. The therapy disrupts the virulence structure of the bacteria, resulting in bacterial death. Currently, chemical drugs have resulted in many resistant bacteria, so it is necessary to find alternative natural materials that are not toxic and do not quickly induce resistance.Aims:This study aimed to analyze the potential of methanol extract from Black soldier fly (BSF) prepupae as an antibacterial agent against Staphylococcus aureus and Aeromonas through in silico and in vitro tests. Methods:The BSF prepupae methanol extract was analyzed for protein and fatty acid contents. Disc diffusion method, minimal inhibitory concentration, and minimum bactericidal concentration test were used for in vitro tests against Staphylococcis and Aeromonas. Molecular docking of the active ingredients (defensin, chitin, and chitosan as well as fatty acids) in BSF was downloaded from the NCBI database and docked by the Hex Cuda version 8.0 program with Correlation type parameters Shape + Electro and Grid Dimension version 0.6. Docking results were analyzed using the Discovery Studio program version 21.1.1.Results:The highest fatty acid contents in the extract were palmitic acid and myristic acid. Methanol extract from BSF prepupae acted as a bactericidal agent against S. aureus at a concentration of 320 mg/ml, in contrast to Aeromonas, which still showed bacterial growth. The results of the in silico test showed that defensin–aerolysin and defensin–hemolysin was bound to the same active site area. However, the amount of binding energy produced by 69-Defensin-83-aerolysin was higher than all defensin types in BSF against Aeromonas. Chitin and chitosan showed a bond on the active site of aerolysin and hemolysin, but chitosan had a stronger bond than chitin. In silico study also showed the strongest binding affinity of BSF fatty acids to isoleucyl-tRNA synthetase of S. aureus.Conclusion:The study showed that methanol extract from BSF prepupae had potential capability as an antibacterial agent against S. aureus than Aeromonas in vitro and in silico.