细菌对四环素类抗生素的耐药机制研究进展

四环素类药物为广谱抗生素,广泛用于临床治疗,并常被用做动物促生长剂,但耐药性的出现限制了该类药物的使用.四环素类药物产生耐药性的机制主要有核糖体保护作用、外输泵作用及产生钝化酶等.本文详细综述了其耐药机制的研究进展及耐药基因的发生率.     

牛奶中四环素类抗生素放射免疫检测方法验证分析

验证了牛奶中四环素类抗生素残留检测的放射免疫方法。该法检测牛奶中四环素、土霉素、金霉素3种四环素类药物的最低浓度可分别达到30、100、50μg/L,RSD(n=6)均小于3.9%。该方法特异性强,与环丙沙星、链霉素、青霉素G、阿莫西林、磺胺嘧啶、磺胺甲基嘧啶、红霉素、螺旋霉素无交叉反应。因此,该法能达到检测牛奶中四环素类抗生素残留的要求。     

猪肉组织中四环素类药物残留检测——高效液相色谱-串联质谱法研究

建立了猪肉组织中四环素类药物残留检测的高效液相色谱-串联质谱方法.色谱条件为色谱柱为XBridge C18柱(150 mm×2.1 mm,5 μm),流动相为0.3%甲酸乙腈溶液 0.3%甲酸水溶液;柱温 20 ℃,流速0.2 mL/min;进样量20 μL.质谱条件为电喷雾离子源(ESI );多反应监测(MRM)方式采集.外标法定量.结果表明,四环素、土霉素和金霉素在10～400 ng/mL浓度范围内呈现良好线性,相关指数R2均大于0.999;方法检测限为5 ng/g,定量限为10 ng/g.50、100和200 ng/g三个添加浓度的平均回收率为72.3%～94.6%,批内批间RSD均小于20%.     

Survey of Tetracyclines, Sulfonamides, Sulfamethazine, and Quinolones in UHT Milk in China Market

This study surveyed 180 samples of ultra high temperature (UHT) milk of four top Chinese dairy brands collected in the 25 cities in China in June 2011, and assessed their contamination with antibiotics, using the ELISA method. The percentages of tetracyclines, sulfonamides, sulfamethazine, and quinolones detected in the samples were 0, 16.7, 40.6, and 100%, respectively. The maximum concentrations of the tetracyclines, sulfonamides, sulfamethazine and quinolones in UHT milk samples were <1.5, 26.2, 22.6, and 58.8 μg kg-1, respectively. None of the samples exceeded the maximum residue levels (MRLs) for these four veterinary drugs, according to the regulations set by China, the European Union (EU) and the Codex Alimentarius Commission (CAC).     

Use of veterinary drugs in intensive animal production

Background. Veterinary drugs are widely used in animal production and possibly reach soil and water through the excreta. There is only limited information concerning the environmental persistence of these substances. Tetracyclines represent the most frequently used antibiotics and accounted for more than 50% of the total amount of veterinary drugs employed through veterinary purchase orders in the Weser-Ems district in 1997. Objectives. It was therefore the objective of the present study to investigate the excretion patterns of tetracycline hydrochloride in pigs after oral application and to study the stability of tetracycline in pig slurry under different storage conditions. Methods 6 individually kept pigs were orally treated with two doses of tetracycline for 5 days and pooled excreta were regularly sampled. Stability testing was performed using 300 1 tanks which were spiked with 20 and 100 μg ml^-1 tetracycline and stored at different ambient temperatures for seven weeks. 181 random pig slurry samples were obtained from commercial farms. Tetracycline and its epimer 4-epi-tetracycline were detected using HPLC. Results Orally applied tetracyclines were rapidly excreted via feces and urine, and significant amounts (up to 72%) of the active ingredient which had initially been dispensed were recovered until the second day after the end of application. Individual animals continued to excrete tetracyclines over a longer period of time. Tetracycline hydrochloride demonstrated a distinct stability in slurry which was not significantly influenced by the initial concentration of the antibiotic, ambient temperature or aeration through repeated stirring. Half-lives ranged between 55 and 105 days. Conclusion Significant amounts of tetracycline are transferred to soil via manure application. There is considerable need for further research into environmental effects such as sorption and mobility, and microbiological changes. This is also the case for other substances which have not undergone valid environmental risk assessment.     

超高效液相色谱-串联质谱法测定牛乳、发酵乳和乳粉中四环素类药物残留

建立超高效液相色谱-串联质谱法同时检测牛乳、发酵乳和乳粉3 种基质中4 种四环素类药物残留的检测方法。对前处理方法和仪器上机条件进行研究。以EDTA-Mcllvaine缓冲液进行提取,经HLB固相萃取柱净化,甲醇-乙酸乙酯（1∶9,V/V）洗脱,氮吹后复溶,采用电喷雾离子源正离子模式、多反应监测模式进行检测。结果表明：乳粉中四环素、土霉素、金霉素和强力霉素的定量限均为10 μg/kg;液态乳和发酵乳中4 种药物的定量限均为2 μg/kg;四环素类药物添加量为2～100 μg/kg时,回收率为63.1%～1     

四环素类抗生素降解菌的分离与鉴定

为了获得四环素类抗生素的高效降解菌,从长期受四环素类抗生素污染的土壤中分离、重复驯化筛选得到6株对四环素类抗生素具有降解能力的菌株;采用高效液相色谱法研究了6株降解菌的降解效果,并通过形态、生理生化特征及16S rDNA序列分析对其进行鉴定。结果表明,菌株TJ-2#对土霉素、四环素和金霉素3种四环素类抗生素的降解效果最好,降解率分别为58.3%、63.9%和65.5%,TJ-6#其次;6株降解菌均能以四环素类抗生素作为唯一碳源生长。经形态、生理生化特征及16S rDNA鉴定,菌株TJ-2#为木糖氧化无色杆菌(Achromobacter sp.),TJ-6#为枯草芽胞杆菌(Bacillus sp.)。本研究结果对四环素类抗生素的生物降解具有一定的现实意义。     

抗感染药在抗支原体上的应用与进展

综述了替米考星和罗红霉素等大环内酯类抗生素，沙拉沙星和二氟沙星等氟喹诺酮类抗菌药以及多西环素等四环素类抗生素在抗支原体上的应用与进展。     

高效液相色谱法检测饲料中四环素类药物含量研究进展

对饲料中4种四环素类药物(土霉素、四环素、金霉素、强力霉素)的高效液相色谱检测方法进行了分析和总结,并探讨了不同流动相、提取溶剂、净化方式的优点和缺点。