水土比、pH和有机质对沉积物吸附四环素的复合影响

为更深入了解抗生素在水环境迁移过程中受沉积物吸附影响的特征和规律,选取典型抗生素之四环素(TC)为代表,研究了不同水土比、pH及有机质对九龙江沉积物吸附TC的复合影响。通过在不同水土比条件下进行改变pH的吸附实验考察水土比和pH的复合影响,又以去除有机质前后的沉积物为吸附剂,在不同水土比、pH条件下对初始浓度范围为20~100 mg·L~(-1)的TC溶液进行等温平衡吸附试验,研究有机质在不同环境条件下对沉积物吸附TC的影响。结果显示pH的影响规律为:沉积物对TC的吸附率总是在酸性条件(pH=3~5)下出现最大值,并且吸附率总体上会随着pH的升高而降低。水土比的影响规律为:水土比的变化会使达到最大吸附率的pH位点和最大吸附率值都发生改变,如:水土比为0.125和0.25时,吸附率在pH=3时达到最大,分别是96.8%和95.3%;水土比0.5时,达到最大吸附率的pH值为5,且最大吸附率值降低至82.82%。这可能是吸附方式由阳离子交换转变为离子交换和配位络合的综合作用导致的。沉积物中有机质的影响研究发现,有机质不是单一的促进或抑制作用,而是在TC形态和沉积物的主要吸附方式发生变化的时候,其促进和抑制作用发生转换。     

Sensitivity of Certain Porcine and Bovine Mycoplasmas to Antimicrobial Agents in a Liquid Medium Test Compared to a Disc Assay

The sensitivity of some porcine and bovine mycoplasmas to potent antimicrobial agents was examined. Minimal inhibitory concentration (MIC) values were estimated for M. hyosynoviae, M. hyopneumoniae, M. dispar and M. bovis against enrofloxacin, lincomycin, tetracycline, tiamulin and tylosin, in a liquid medium test and in a disc assay. All 6 examined strains of each species and the respective type strains were significantly inhibited. The greatest sensitivity was noted for tiamulin against strains of M. hyosynoviae with a final MIC₅₀ broth value of 0.025 µg ml⁻¹ and disc value of 0.03 µg per disc. Enrofloxacin was found very potent against M. hyopneumoniae with a final MIC₅₀ of 0.025 µg ml⁻¹ and 0.1 µg per disc, and for M. dispar with 0.05 µg ml⁻¹ and 0.03 µg per disc.Most disc assay estimates in ug per disc were similar to or moderately greater than corresponding final broth figures in µg ml⁻¹. It may be possible to convert observed disc assay values into representative final broth MIC values for use in the clinic.     

牛奶中四环素类药物残留的确证方法--液质联用法

为了确证牛奶中土霉素、四环素、金霉素的残留，建立了电喷雾高效液相色谱／串联质谱法，采用正离子检测，选择离子方式扫描。牛奶样品经Mcllvaine-EDTA缓冲溶液提取离心后，上清液过C18小柱净化后甲醇洗脱，然后氮气吹干，甲醇-水（30：70）溶解（以去甲金霉素为内标）后进行分析。结果表明，牛奶中土霉素、四环素和金霉素的检测限（LODs）为0．01mg／L，定量限（LOQs）为0．025mg／L。3种药物在0．05～0．5mg／L范围内均呈良好线性关系，并且3个添加浓度的平均回收率范围为70．0％～87．6％，批内变异系数不大于10％，以最大残留限量浓度添加后所测得回收率的批间变异系数小于15％。本方法特异性强、灵敏度高、准确可靠，可作为牛奶及其他动物组织中四环素类药物残留的确证方法。     

Pemphigus: current therapy

Pemphigus is an autoimmune skin disease that can present in a variety of forms and can be a challenging disease to manage and treat. An overview of the different forms of pemphigus and diagnostics are discussed including pemphigus foliaceus (PF), pemphigus erythematosus (PE), panepidermal pustular pemphigus (PPP), pemphigus vulgaris (PV) and paraneoplastic pemphigus (PNP). Emphasis on therapy is presented. Included are the most current commonly used therapeutics (glucocorticoids, azathioprine, chlorambucil and tetracycline and niacinamide); current alternative therapeutics (cyclosporin and tacrolimus and mycophenolate mofetil) and additional alternative therapeutics (cyclophosphamide, chrysotherapy, dapsone, sulfasalazine and intravenous immunoglobulin (IVIG) therapy).     

重金属与四环素类抗生素对发光菌的毒性研究

本研究以发光细菌Photobacterium kishitanii为模式生物,通过发光抑制试验研究了5种重金属与四环素类抗生素对发光细菌的急性单一毒性与联合毒性。利用毒性单位法（TU法）表征联合毒性,并采用浓度加和模型（Concentration addtion,CA模型）与独立作用模型（Independent action,IA模型）预测二元混合体系对发光细菌的联合急性毒性。研究表明：单一毒性大小排序为硝酸铅>七水硫酸锌>氯化镉>盐酸土霉素>盐酸金霉素>盐酸强力霉素>盐酸四环素>五水硫酸铜>重铬酸钾。重金属之间的联合毒性主要表现为协同作用,重金属与四环素类抗生素的联合毒性主要表现为相加作用和拮抗作用,四环素类抗生素之间的联合毒性主要表现为拮抗作用。研究表明,重金属与四环素类抗生素共存会对发光细菌产生不同的毒性效应,因此在评价环境复合污染时应考虑联合毒性效应。     

施用猪粪对蔬菜生长及土壤抗生素、重金属含量的影响

为研究施用含有多种抗生素和重金属元素残留的猪粪有机肥对土壤和作物的影响，采用1年大田试验比较腐熟猪粪和新鲜猪粪对土壤中四环素类抗生素[四环素(TC)、土霉素(OTC)、金霉素(CTC)]、抗性菌和重金属(Cu、Cd、Ni、Pb、Zn、Cr)的残留量及对土壤抗性菌数量及蔬菜产量的影响。结果表明，水白菜、菜心、莴苣、青梗菜4种蔬菜新鲜猪粪处理（FPM处理）的产量较腐熟猪粪处理（CPM处理）分别增加了11.3%、3.2%、75.0%和6.8%，施用CPM 1年后的土壤anti-OTC和anti-TC比FPM高73.07%和40.89%，其anti-OTC抗性菌占细菌总数的比例分别比FPM和CK（不施用猪粪的对照处理）显著高163.10%和307.10%，anti-CTC显著高于对照52.3%。施用CPM和FPM的土壤四环素类抗生素TC、OTC、CTC含量及总量显著增加，土壤Cd、Cu、Zn含量分别较对照土壤增加52.7%、33.7%和29.8%(CPM)，8.7%、24.1%和16.9%(FPM)。土壤中Cd、Cu、Zn含量CPM>FPM>CK。施用猪粪会造成土壤中四环素和重金属的累积。     

东方蜜蜂采集的野坝子蜂蜜分析研究

 在冬季野坝子花期,研究了云南武定、姚安、大姚、祥云和永胜等5个野坝子主要分布地区15个不同海拔点东方蜜蜂(Apis cerana F．)采集的野坝子蜂蜜,根据国家标准GB18796—2005,对其进行了花粉、感官指标和理化指标、四环素族抗生素残留量分析。各采样点东方蜜蜂采集的野坝子蜂蜜中均含有野坝子花粉,且数量均大于50%;感官分析表明：各个蜂蜜样品色泽均一相近,气味较浓郁,滋味上没有明显区别。理化分析表明：各个蜂蜜样品的水分、还原糖、蔗糖含量、灰分、羟甲基糠醛、酸度、淀粉酶活性的指标均符合国家标准GB18796—2005;四环素族抗生素残留量分析：结果显示所有被检蜂蜜样品,均未检出四环素族抗生素残留。     

胸膜肺炎放线杆菌对四环素类抗生素的耐药分析及相关基因检测

四环素类药物是在兽医临床中常用的一类抗生素,为了解胸膜肺炎放线杆菌(Actinobacillus pleuropneumoniae,APP)对四环素类抗生素的耐药情况,本研究对从临床分离鉴定的85株APP进行了四环素类抗生素临床耐药情况和相关基因的分析和检测。应用药敏纸片法进行药敏试验,结果:APP对四环素的耐药率较高为76.5%,其次为金霉素54.1%、美他环素48.2%、多西环素45.9%、土霉素28.2%、米诺霉素25.9%、替加环素22.3%。采用PCR方法对四环素类10种耐药基因tetA、tetB、tetC、tetD、tetE、tetG、tetH、tet1、tetL1和tetL2进行检测,结果:tetA、tetB、tetC、tetD、tetE、tetG、tetH、tet1、tetL2、tetL1耐药基因的扩增阳性率分别为78.8%、41.2%、15.3%、8.2%、21.2%、15.3%、43.5%、24.7%和30.6%,而tetL1扩增则全部阴性,未检出其耐药基因。本研究结果为四环素类抗生素在猪传染性胸膜肺炎临床上的应用和新药研发提供了一定的理论依据。     

Assessing Bioactive Tetracycline in Soil Samples. Application of a German-Standard-Bioassay DIN 58940 Part 1–3 (5 pp)

Background   Tetracycline (TC) is one of the most common antibiotics in animal husbandry. Concentrations of up to 200 µg TC kg–1 have been found in soils, which have repeatedly received pig manure, and it can be assumed that there is an accumulation in soil. Methods   The established methods for chemical analysis of extractable TC in soil employ HPLC-UV or HPLC-MS-MS. These methods are quite expensive and require well-trained laboratory personnel and sophisticated high-technology equipment. For this reason, a German Standard Bioassay (DIN 58940 Part 1–3) was adjusted and validated in order to establish an alternative low-priced method for monitoring TC contents in soil samples. The tests were conducted with two soils (sand and loamy sand) spiked with TC at 6 concentrations. With this bioassay, TC in soils was analyzed and a simple quantification procedure was established. It will be demonstrated that sand and loamy sand soil properties have an influence on the recoveries of extractable, bioactive TC. Results   In the loamy sand soil, less bioactive TC was extracted (15–25%) than in the sandy soil (30–55%), when tested against the aqueous TC-solution (100%) as a control. These results were confirmed by HPLC- MS-MS analyses. The bioassay was successfully employed in a degradation study in a greenhouse pot experiment.Recommendation   It could prove to be expedient to use this bioassay in the assessment of other antibiotics as well.