猪鸡致病菌β-内酰胺酶、超广谱β-内酰胺酶检测与药敏试验

 对分离的猪鸡致病菌，分别进行了?－内酰胺酶、超广谱β-内酰胺酶(ESBLs)检测，并用试管二倍稀释法测定了β－内酰胺环类抗生素或β－内酰胺环类抗生素与抑制剂舒巴坦联用对非产酶菌、产?－内酰胺酶菌、产ESBLs菌的抗菌活性。结果表明，43株分离菌的大多数可产生?－内酰胺酶，3株鸡志贺氏菌为ESBLs阳性菌株。30株分离产酶菌均对阿莫西林、氨苄西林耐药（MIC≥32 ?g/ml），16株非产酶菌（标准菌株及分离株）中的15株对阿莫西林、氨苄西林敏感，只有一株非产酶分离菌耐药。氨苄西林与舒巴坦以2∶1、4∶1配比联用时，其对分离产酶菌的MIC值分别降低10~40倍、10~20倍。临床致病菌对三代头孢均敏感，与舒巴坦以2∶1、4∶1配比联用时，三代头孢的MIC值不变。当头孢噻呋、头孢曲松与舒巴坦以2∶1配比联用时，其对产ESBLs菌的MIC值降低2～4倍。     

福建省黄曲条跳甲药剂敏感性的地区差异

利用浸叶法对福建省不同地区黄曲条跳甲的药剂敏感性水平进行测定,结果表明不同地区的黄曲条跳甲对毒死蜱、丁硫克百威、敌敌畏的药剂敏感性普遍处于敏感性下降到低抗水平,少数菜区达到中等抗性水平;不同地区的黄曲条跳甲对氯氰菊酯的药剂敏感性差异较大,部分地区达到中抗或高抗水平.总体上,闽东南沿海地区的黄曲条跳甲药剂敏感性水平普遍低于闽西北地区.     

呼和浩特市地区桃粉蚜(Hyalopterus amygdali Blanchard)对七种杀虫剂的敏感性研究

桃粉蚜(Hyalopterus amygdali Blanchard)是农作物和果树重要害虫。本研究,为揭示呼和浩特市地区桃粉蚜对不同杀虫剂的敏感性。应用拟除虫菊酯类、新烟碱类、阿维菌素类等7种杀虫剂对其进行生物测定。试验结果：1.拟除虫菊酯类,SEQ品系对溴氰菊酯、氟氯氰菊酯和联苯菊酯的LC50值分别是395.20mg/L、29.90mg/L、86.40mg/L。IMAU品系对溴氰菊酯、氟氯氰菊酯和联苯菊酯的LC50值分别是591.29 mg/L、1219.30 mg/L、271.81 mg/L。SEQ品系对拟除虫菊酯类杀虫剂的敏感性比IMAU品系高。2.新烟碱类,SEQ品系对吡虫啉和啶虫脒的LC50值分别是400.23mg/L、395.80mg/L。IMAU品系对对吡虫啉和啶虫脒的LC50值分别是340.93mg/L、838.28mg/L。SEQ品系和IMAU品系对新烟碱类杀虫剂的敏感性差异不大。3.阿维菌素类,SEQ品系对阿维菌素和甲氨基阿维菌素苯甲酸盐的LC50值分别是166.40mg/L、1279.96mg/L。IMAU品系对阿维菌素和甲氨基阿维菌素苯甲酸盐的LC50值分别是878.73 mg/L、6716.83 mg/L。SEQ品系对新烟碱类杀虫剂的敏感性比IMAU品系高。本研究中的SEQ品系对拟除虫菊酯类、阿维菌素类杀虫剂的敏感性均比IMAU品系的高。SEQ和IMAU品系对拟除虫菊酯和阿维菌素类杀虫剂均有敏感性差异与不同生态环境中的种群受杀虫剂筛选频度有关。同类杀虫剂的靶标部位相同导致桃粉蚜均对3类杀虫剂产生交互抗性。本研究为农业生产当中防治桃粉蚜提供基础数据。     

Properties of Urbic Anthrosols from an abandoned shunting yard in the Ruhr area, Germany

The soil conditions of an abandoned shunting yard in the Ruhr area were studied to find the most important factors influencing plant growth and nutrient cycling. The chemical and physical conditions of five Urbic Anthrosols with different development histories were compared with those of a nearby Calcic Cambisol under agricultural use. In the second half of the 19th century, the ground level of the shunting yard site was raised about 2 m. The soils are now mainly Regosols, mostly well drained in the topsoil. The coarse material contents (>2 mm), which are up to 100% in base layers of railway tracks, and the quality of the man-made substrates (crushed rock, slags, ashes, coke) are the most important factors influencing plant growth. Poor physical structure and low contents of fine fraction (<2 mm) lead to low water storage. Together with a low available nutrient stock, these properties lead to poor establishment of vegetation. The burning of coal by steam engines produced highly polluted ashes that fill pore spaces in the railway ballast layers. All the investigated fine substrata of the shunting yard layers exhibit a higher magnetic susceptibility than the rural soil. The ashes still contain unburned coal so that, although the total organic C content of the man-made soils reaches 37%, the wide C:N ratio does not indicate the actual quality of humic substances. The acid neutralization potential of the topsoil layers of the shunting yard will be consumed by acidic atmospheric deposition within a few decades, whereas in the surrounding Calcic Cambisols, it will take more than a thousand years. This may cause further problems of groundwater quality, as the heavy metals will become more soluble. The low soil quality makes such sites suitable for vegetation species that cannot compete in the surrounding very eutrophic agricultural landscape.     

乌鲁木齐城市土壤磁化率特征及其环境意义

对乌鲁木齐市区及其周边地区45个地点的土壤样本进行磁化率测定。结果表明,乌鲁木齐城市土壤磁化率大都处于中低值区域,具有空间差异性的特征,进而结合采集点的土壤环境状况分析了乌鲁木齐城市土壤的环境特征,探讨乌鲁木齐城市土壤磁化率表征下土壤污染的影响机制。     

乳酸杆菌LH对水产常用药物的敏感性

采用试管法,以金黄色葡萄球菌ATCC25922为质控菌,研究乳酸杆菌LH菌株对氟苯尼考、土霉素、二氧化氯、二溴海因、强力碘的敏感性。结果显示,在5.0×105cfu/mL时,最小抑菌浓度分别为2μg/mL、4μg/mL、16μg/mL、32μg/mL、32μg/mL,最小杀菌浓度分别为16μg/mL、64μg/mL、128μg/mL、128μg/mL、128μg/mL;最小抑菌浓度随着菌悬液浓度(104~107cfu/mL)的增大而升高;在杀菌曲线中,药物对菌的抑制作用随着作用时间的延长而逐渐减弱。     

Prevalence,Serovars and Antimicrobial Susceptibility of Salmonella spp. from Wild and Domestic Green Iguanas (Iguana iguana) in Grenada,West Indies

Cloacal swabs from 62 green iguanas (Iguana iguana), including 47 wild and 15 domestic ones from five parishes of Grenada, were sampled during a 4‐month period of January to April 2013 and examined by enrichment and selective culture for the presence of Salmonella spp. Fifty‐five per cent of the animals were positive, and eight serovars of Salmonella were isolated. The most common serovar was Rubislaw (58.8%), a serovar found recently in many cane toads in Grenada, followed by Oranienburg (14.7%), a serovar that has been causing serious human disease outbreaks in Japan. Serovar IV:48:g,z₅₁:‐ (formerly, S. Marina) highly invasive and known for serious infections in children in the United States, constituted 11.8% of the isolates, all of them being from domestic green iguanas. Salmonella Newport, a serovar recently found in a blue land crab in Grenada, comprised 11.8% of the isolates from the green iguanas. The remaining four less frequent serovars included S. Javiana and S. Glostrup. Antimicrobial susceptibility tests conducted by a disc diffusion method against amoxicillin–clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, streptomycin, tetracycline and trimethoprim–sulfamethoxazole showed that drug resistance is minimal, with intermediate susceptibility, mainly to streptomycin, tetracycline and cefotaxime. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars from wild and domestic green iguanas in Grenada, West Indies.     

Tilapia Lake Virus was not detected in non-tilapine species within tilapia polyculture systems of Bangladesh

Sixteen countries, including Bangladesh, have reported the presence of tilapia lake virus (TiLV), an emerging tilapia pathogen. Fish polyculture is a common farming practice in Bangladesh. Some unusual mortalities reported in species co-cultivated with TiLV-infected tilapia led us to investigate whether any of the co-cultivated species would also test positive for TiLV and whether they were susceptible to TiLV infection under controlled laboratory experiments. Using 183 samples obtained from 15 farms in six districts across Bangladesh, we determined that 20% of the farms tested positive for TiLV in tilapia, while 15 co-cultivated fish species and seven other invertebrates (e.g. insects and crustaceans) considered potential carriers all tested negative. Of the six representative fish species experimentally infected with TiLV, only Nile tilapia showed the typical clinical signs of the disease, with 70% mortality within 12 days. By contrast, four carp species and one catfish species challenged with TiLV showed no signs of TiLV infection. Challenged tilapia were confirmed as TiLV-positive by RT-qPCR, while challenged carp and walking catfish all tested negative. Overall, our field and laboratory findings indicate that species used in polycultures are not susceptible to TiLV. Although current evidence suggests that TiLV is likely host-specific to tilapia, targeted surveillance for TiLV in other fish species in polyculture systems should continue, in order to prepare for a possible future scenario where TiLV mutates and/or adapts to new host(s).