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81.
ZHI Chan-ping GUO Xiao-ting YAO Xu GUO Ze-wen WU Sheng-jun YI Ling-xian CHENG Bang-zhao WANG Jun-jun LIU Jian-hua 《中国畜牧兽医》2015,42(12):3351-3357
To determine the drug resistance of E.coli strains from swine and chicken in organic farm,collection of stool specimens was conducted in one organic farm in Conghua city,Guangdong province in 2014,in which 118 E.coli strains were separated,including 55 from chicken and 63 from swine.The sensitivity of the E.coli strains from swine and chicken to 18 kinds of drugs was detected through agar dilution method.Similar properties in drug resistance were observed both in E.coli strains from swine and chicken in the same organic farm.In consideration of the resistance rate,samples were relatively sensitive to ceftazidime,cefquinome,cefoxitin,amikacin,apramycin,gentamicin,neomycin,florfenicol,chloramphenicol,imipenem,ciprofloxacin and olaquindox (chicken 0 to 21.8%;swine 0 to 14.3%).These isolates showed moderate resistance to ampicillin and streptomycin (chicken 29.1% to 38.2%;swine 23.8% to 27.0%).About 56.4% chicken isolates and 47.6% swine isolates showed resistant to more than 3 kinds of drugs.However,severe resistance was observed in trimethoprim-sulphamethoxazole,tetracyclineand and doxycycline (chicken 45.5%,76.4% and 72.7%;swine 50.8%,81.0% and 68.3%).The results also indicated that under organic farming mode,the drug resistance rates of E.coli strains from swine and chicken were relatively low in general.Multi-drug resistance existed but was relatively slight.Although the drug resistance rate to several specific antimicrobials was high,it was still lower than that in conventional farms.Since most studies focused on the drug resistance of the bacteria under conventional farming model,this study filled the blank of the research of drug resistance under organic farming model. 相似文献
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Gram-positive cocci were isolated from half a month diseased lambs with a fatal infection in a sheep farm in Minhe county, Qinghai province.The clinical symptoms observed were drooping, reduced feed intake, emaciated and fever.The infected lambs died several hours after the disease been observed.Necropsy of two dying lambs revealed that for one lamb, the liver was enlarged and capsule of the liver dropped, and other organs had no obvious changes;For the other one, the organs had no obvious changes.After gram staining, gram-positive cocci were observed from all the samples.Partial Tuf gene sequences of these isolates were amplified and sequenced for species identification, BLASTn conparison result revealed that they had the highest sequence similarity with that of Enterococcus faecium (E.faecium) AUS0085 (99.8%), we thus primarily confirmed that these strains belonged to E.faecium.Antimicrobial susceptibility test indicated that these strains could be divided into two classes.Class 1 was resistant to β-lactams, aminoglycosides, macrolides, tetracyclines, quinolones, rifamycins, lincomycin and clindamycin;Susceptible to chloromycetin and vancomycin.Class 2 was resistant to β-lactams, aminoglycosides, tetracyclines, quinolones, rifamycins;Intermediate resistance to erythromycin and roxithromycin;But susceptible to clarithromycin, azithromycin, clindamycin, lincomycin, chloromycetin and vancomycin.Multilocus sequence typing (MLST) based on seven housekeeping genes for E.faecium revealed that E.faecium lby1 strain in class 1 and E.faecium lbg3 strain in class 2 were defined as a new sequence type ST989.Phylogenetic tree analysis revealed the representative strain of these isolates, E.faecium lbg3, was clustered together with E.faecium ST468.The pathogenicity test revealed that E.faecium lby1 and lbg3 strains both had pathogenicity. 相似文献
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本文报道了按照森林土壤标准物质要求采集的二个土壤样品(碱性土-碱灰性褐土;酸性土-黄红壤)和一个植物样品(杉木叶)的制备过程,粒径2mm的土壤样品采用Y型混样,0.149mm的土壤和0.177mm的植物样品采用高铝瓷球磨制备,土壤样品用高湿灭活,植物样品用^60Co辐射灭活,在二年测定标准样品稳定性和同时进行标准样品中微生物类群和数量的分析。土壤、植物标准样品的均匀性和稳定性采用数理统计方法检验,其结果均达到标准物质要求。 相似文献
86.
本文依据美国白蛾发生、危害症状、寄主、虫态、特征、发生期、传播方式等方面的特点与规律,探讨了美国白蛾的监测检疫检验技术程序与方法。 相似文献
87.
本文运用协整理论中的E-G两步协整检验方法,研究了外商在中国的直接投资和中国外汇储备之间的相关关系,并根据Granger因果检验模型,考察了两者的因果关系,建立了误差修正模型.实证结果表明,外商在中国的直接投资与中国外汇储备之间具有长期均衡关系,且后者对前者存在单向因果关系. 相似文献
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多重集合的运算研究与应用 总被引:1,自引:1,他引:1
申初连 《中南林业科技大学学报(自然科学版)》2007,27(3):145-147
集合是现代数学中最基本的概念之一,并已深入到各种学科和技术领域中.而作为集合概念扩展的多重集合概念,却少有应用.通过对多重集合进行系统研究,提出了多重集合的包含、相等、多重幂集,以及多重集合补集等相关概念和运算,建立了多重集合完善的理论体系,并给出了多重集合在古典概率中的应用.为进一步研究多重集合在各种学科和技术领域中的应用打下了良好的基础. 相似文献
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