Bacterial resistance to quinolone antibiotics in Poland

The resistance of 167 pathogenic bacteria of animal origin to quinolones was determined by the disc diffusion method, and by the minimum inhibitory concentration (MIC) test. The highest resistance of Escherichia coli was found to be against nalidixic acid (NA), 49.1% and flumequine (FLU), 38.2%. The sensitivity of the strains were: ciprofloxacin (CIP; 81.8%); enrofloxacin (ENR; 81.8%); norfloxacin (NOR; 80.0%); and pefloxacin (PE; 76.4%). Salmonella spp. showed 100% sensitivity to CIP, ENR, NOR and PE. A high resistance percentage in the cases of: FLU (86.7%); PE (50.0%); and CIP (26.65%) distinguished the Streptococcus spp. The highest percentage sensitivity of Staphylococci was found with three fluoroquinolones: CIP, ENR and NOR, 94.3% each (66 strains). The studies did not indicate that a total cross-resistance might occur between the examined quinolones.     

植物对重金属镉的响应及其耐受机理

重金属Cd作为非必需微量元素,经根系吸收并累积时对植物具有很强的毒性,因而开展植物对Cd的响应途径及其调控机理研究,对改良植物对Cd的耐受性以及开发超累积植物均具有重要意义.植物硫代谢、抗氧化系统和Cdz2 跨膜运输是植物对重金属镉响应的主要途径,本研究综述了以上3种耐受机制的研究进展,包括Cd2 诱导植物硫转运蛋白、硫还原相关酶类以及半胱氮酸、谷胱廿肽和植物螯合肽合成及其基因表达调控,Cd2 诱发的植物抗氧化反应及其基因表达,质膜和液泡转运蛋白促进Cd2 运输和隔离的基因调控.     

喹/诺/酮/类/抗/菌/药/耐/药/新/机/制

近年来喹诺酮类的耐药性问题备受关注。细菌对喹诺酮类的耐药机制过去普遍认为主要起因于染色体基因突变(靶位改变、主动外排和膜孔蛋白缺失),而不存在水平传播的可转移基因。近年来开始出现一些新的喹诺酮耐药机制,包括qnr、mfpA和氨基糖苷乙酰转移酶的变异基因(aac(6’)-Ib-c     

截短侧耳类药物耐药机制研究进展

截短侧耳类抗菌药物泰妙菌素和沃尼妙林是兽医专用药。随着病原菌对现有药物的耐药性在全球范围蔓延,现在兴起了开发新的截短侧耳衍生物用于治疗人类细菌感染。瑞他帕林(Rapamulin)是第一个用于人医的截短侧耳类药物,2007年被批准用于由金黄色葡萄球菌(Staphylococcus aureus)和酿脓葡萄球菌(Staphylococcus pyogenes)引起的皮肤感染。截短侧耳衍生物在人医上的开发应用使其耐药机制成为国际上的研究热点。本文就截短侧耳类药物耐药机制及其传播机理的研究进展进行综述。     

Identification of mechanisms of natural resistance to African trypanosomiasis in cattle

Natural resistance to African trypanosomiasis in certain Bos taurus cattle in West Africa, called trypanotolerance, may hold solutions for control of this economically crippling disease. Comparison of immune responses between trypanotolerant and trypanosusceptible cattle have shown some differences in antibody response, complement level and cytokine expression, but it is not known whether these differences are the cause of resistance.Two experiments were carried out to assess the contribution of the immune and haemopoietic systems to trypanotolerance. The production of haemopoietic chimaeras from trypanotolerant and susceptible twin calves and comparison of their responses after infection with singleton calves, allowed an assessment of the role of the haemopoietic system in trypanotolerance. An in vivo depletion of CD4 cells in the two breeds allowed an appraisal of the role of T and B lymphocytes in trypanotolerance. The results of the two experiments suggest that natural resistance comprises at least two mechanisms, an innate mechanism that controls parasite growth, and another, involving the haemopoietic system, that is able to limit anaemia. This supports the hypothesis that innate mechanisms in trypanotolerant cattle are more efficient in controlling disease, making them less reliant on antibody responses.     

Chlortetracycline residues in the meat of slaughter calves in relation to transmissible microbial resistance to antibiotics

The occurrence of chlortetracycline residues in the meat of slaughter calves in 62% herds under study (the additive of the medicated premix AUREOVIT to feed without observing the withdrawal times) did not influence significantly the Gram-negative resistant and R+ microflora isolated from the same material, in comparison with control herds that were administered no antibiotics. Neither was the spectrum of donors and transferring R plasmids influenced significantly nor the incidence of different resistance determinants. The effect of chlortetracycline addition to feed was negative (at P = 0.05) only in the occurrence of R+ microflora isolated from stable environment where the slaughtered calves had been housed.     

动物源细菌耐药性评估在兽用抗菌药使用减量化行动中的应用

动物源细菌耐药性已引起广泛关注,全国正在逐步推进兽用抗菌药使用减量化行动。为更好地推动减量化行动的实施,浙江省在耐药性的评估及应用方面进行探索。研究分析了耐药性评估在减量化行动中的作用,建立了耐药系数评估模型与应用方法,研判了目前耐药性监测可能存在的问题,以期更好地推进兽用抗菌药使用减量化行动。     

沙门氏菌对喹诺酮类药物耐药性的分子机制

沙门氏菌属(Salmonella)是肠杆菌科中的一个重要菌属。1880年Eberth首先发现伤寒沙门氏菌，1885年Salmon与Smith又分离出猪霍乱沙门氏菌，以后取名Salmon氏之名为本菌属属名。已发现近2000个血清型，我国已发现近200个血清型。沙门氏菌病是主要的消化道传染病之一，仍严重危害人民身体健康，阻碍畜牧业的发展壮大，并带来了巨大的经济损失。     

细菌耐药性产生的分子机制与耐药基因的快速检测方法

细菌产生耐药性成为临床治疗感染性疾病失败的主要原因.本文综述了由自发基因突变和获得性细菌耐药性产生的分子机制,及目前常用的快速检测细菌耐药基因的方法,包括聚合酶链反应-单链构象多态性分析(PCR-SSCP)、质粒指纹图谱分析和PCR-限制性片段长度多肽性分析(PCR-RFLP).     

Prevalence of Campylobacter jejuni and its resistance to antibiotics in poultry in the Czech Republic

Thermotolerant Campylobacter spp., in particular Campylobacter jejuni, are among the most frequently identified pathogens, found to be causing human gastrointestinal infections in Europe, with the Czech Republic being no exception. The presented work aimed at assessing results of the first nationwide monitoring of prevalence and antibiotic resistance of Campylobacter spp. in broiler flocks in the Czech Republic, including a comparison of antibiotic resistance of C. jejuni isolates collected from poultry and the human community. The monitoring was carried out in poultry slaughterhouses in 2006 and 2007. From broilers, cloacal swabs were collected and examined. The human isolates of C. jejuni were acquired from rectal swabs in community patients with diarrhoeal diseases. Suspected isolates of both animal and human origin were confirmed by the PCR methods. Antibiotic resistance to selected anti-microbial agents was tested by the microdilution method. In the monitored period, the prevalence of thermotolerant Campylobacter spp. in broilers in the Czech Republic reached almost 50%. In 2006, C. jejuni was detected in 46% and Campylobacter coli in 3% of the tested samples. In 2007, C. jejuni was found in 43% and C. coli in 2% of the samples. The results of anti-microbial susceptibility testing of C. jejuni showed higher resistance in animals when compared with humans. The only exception was tetracycline with higher resistance in isolates of human origin. The highest resistance detected was to quinolone antibiotics. Resistance to oxolinic acid was 77% in animal and 60% in human isolates, to ciprofloxacin 72% in isolates from poultry and 55% in those from humans. In ampicillin, 26% of poultry isolates and 16% of human isolates were resistant. Moreover, 9% of animal isolates demonstrated resistance to streptomycin, undetected in human isolates. In erythromycin, resistance was found in 6% of poultry and 1% of human isolates.     

猪链球菌的分离鉴定及对常用抗菌药物的耐药性

本试验对某猪场采集的猪鼻腔棉拭子进行猪链球菌的分离纯化及鉴定,采用琼脂扩散法和微量稀释法对鉴定出的猪链球菌进行药敏试验,以美国临床检验标准委员会(NCCLS)的抑菌圈直径和临界浓度做为判断标准。试验结果表明,通过培养特性、染色特点、形态观察、生化试验及PCR鉴定,分离到10株猪链球菌。10株猪链球菌对青霉素G(PEN)、阿莫西林(AMO)的耐药率最低,为0%,对头孢西丁(FOX)、红霉素(ERY)、氧氟沙星(OF)、磺胺甲口恶唑(SMZ)则表现出明显的耐药性,耐药率均达100%,对头孢唑啉(CEZ)、头孢噻呋(CEF)的耐药率在20%～60%之间。