猪场及周边环境中大肠埃希菌对几种消毒剂及抗菌药的耐药性调查     

杨秋娥  李亮  廖晓萍  李幸萍  王明汝  方茜  刘雅红  孙坚 《华南农业大学学报》2015,36(6):15-22

【目的】调查猪场及周边环境中大肠埃希菌Escherichia coli对消毒剂和抗生素耐药情况,分析消毒剂抗性与抗菌药耐药之间的关系.【方法】从广东省某猪场采集130份样品,包括养殖场各阶段猪的粪便、猪场周边环境(猪舍空气、池塘水、周边土壤样品)以及猪场人员的粪便样品.采用选择性培养基分离鉴定大肠埃希菌,琼脂稀释法测定大肠埃希菌对4种消毒剂和10种抗菌药的MIC值,PCR法检测qac E、qac E△1、qac F、qac G、emr E、sug E(c)、sug E(p)、mdf A和ydg E/ydg F消毒剂抗性基因.【结果和结论】130份样品中共分离到97株大肠埃希菌,分离率达74.6%.受试菌株对4种消毒剂表现出不同程度的抗性,不同来源的菌株对季铵盐类消毒剂苯扎氯铵和十六烷基三甲基溴化铵都表现出较高的抗性水平,而对双胍类消毒剂三氯生和氯己定则较为敏感.87.6%(85/97)的大肠埃希菌菌株表现为多重耐药,68%~88%的菌株对磺胺甲恶唑/甲氧苄啶、多西环素、萘啶酸、头孢噻肟和氟苯尼考等抗菌药表现出耐药.消毒剂抗性基因的检出率不高(2.1%~20.6%),其中检出率最高的为qac E△1.大肠埃希菌对季铵盐类消毒剂的抗药性与抗菌药耐药性呈正相关,消毒剂抗性基因与一些特定的抗生素耐药表型也存在一定关联.在磺胺甲恶唑/甲氧苄啶、萘啶酸、环丙沙星、头孢西丁、阿米卡星和黏菌素耐药菌株中,消毒剂抗性基因检出率分别高于其敏感菌株的检测率.抗生素-消毒剂联合耐药给周边环境带来了风险,因此养殖场消毒剂和抗生素应规范使用,以减少细菌耐药性的产生.  相似文献   

一株抗菌活性物质产生细菌的分离及鉴定     

殷杰  王蒙  曾小波  马志勇  程国军 《湖北农业科学》2015,54(2):346-349

从根际土壤分离到一株细菌CY04,通过电镜观察和16S r DNA序列分析,发现该菌株同已知菌枯草芽孢杆菌(Bacillus subtilis)的相似度最高,为99%,初步认定为枯草芽孢杆菌。抑菌试验结果表明,该菌株对金黄色葡萄球菌(Staphylococcus aureus)有一定的抑菌活性,对大肠杆菌(Escherichia coli)和枯草芽孢杆菌没有抑菌活性。培养48 h左右是其产生抗菌活性物质的最佳时期。  相似文献   

S34-1细菌对致病疫霉的抑制作用及其抗菌物质的初步分析     

王翠翠  侯红霞  蒋继志 《河北农业大学学报》2015,(1)

为了明确S34-1细菌对致病疫霉不同生育阶段的影响以及对晚疫病的控制效果,并初步探究拮抗物质的来源。本试验分别以对峙培养法、菌液与孢子囊悬液混合法测试细菌活体和菌液对致病疫霉菌丝生长以及菌体形态的影响,以块茎切片法评价菌液的防病效果,采用排除法探究拮抗物质来源。结果表明,S34-1活体和菌液对致病疫霉菌丝生长有较强的抑制作用,抑菌率分别为89.32%和97.12%;菌液可使菌丝畸形、不规则膨大并释放内含物,明显抑制孢子囊释放游动孢子和游动孢子萌发;在马铃薯块茎切片上菌液对晚疫病有良好的预防效果,其抑菌物质是一种挥发性物质。试验表明利用S34-1菌株防治马铃薯晚疫病有较大潜力。  相似文献   

Identifying physiological traits associated with improved drought resistance in winter wheat   总被引：1，自引：0，他引：1  

M.J. Foulkes  R. Sylvester-Bradley  R. Weightman  J.W. Snape 《Field Crops Research》2007

The association of specific target traits for drought resistance (early flowering, high accumulation of stem water soluble carbohydrate (WSC) reserves, presence of awns and high green flag-leaf area persistence) with yield performance under late-season drought was analyzed utilizing two doubled-haploid (DH) populations derived from crosses between Beaver × Soissons and Rialto × Spark in two seasons 2000/2001 and 2001/2002. The aim was to quantify associations between target traits and yield responses to drought, and to prioritize traits for drought resistance. Flowering time variation had a neutral effect on the absolute yield loss under drought, suggesting there may be a trade-off between water-saving behaviour in the shorter pre-flowering period with early flowering and a reduced capacity to access water associated with a smaller rooting system. The presence of awns also had a neutral effect on yield loss under drought amongst lines of the Beaver × Soissons population. The potential advantages of awns for increasing water-use efficiency and sensible heat transfer responsible for a cooler canopy appeared to be of less significance under moderate droughts in the UK than under severe droughts in other regions worldwide. The value of large stem soluble carbohydrate reserves for drought environments alone could not be confirmed in the UK environment. Stem WSC was positively associated with grain yield under both irrigation and drought. The genetic trait which showed the clearest correlation with the ability to maintain yield under drought was green flag-leaf area persistence. Averaged across years, the positive phenotypic correlation of this trait with yield under drought amongst DH lines of the Beaver × Soissons population (r = 0.49; p ≤ 0.001) indicated the potential use of this trait as a selection criterion for yield under drought. It is suggested that screens for this trait including marker-assisted selection would have value in future breeding programmes aimed at improving yields in high yielding, rainfed environments, but where drought can also be a problem, such as the UK.  相似文献   

Inducible ASABF-type antimicrobial peptide from the sponge Suberites domuncula: microbicidal and hemolytic activity in vitro and toxic effect on molluscs in vivo     

Wiens M  Schröder HC  Korzhev M  Wang XH  Batel R  Müller WE 《Marine drugs》2011,9(10):1969-1994

Since sponges, as typical filter-feeders, are exposed to a high load of attacking prokaryotic and eukaryotic organisms, they are armed with a wide arsenal of antimicrobial/cytostatic low-molecular-weight, non-proteinaceous bioactive compounds. Here we present the first sponge agent belonging to the group of ASABF-type antimicrobial peptides. The ASABF gene was identified and cloned from the demosponge Suberites domuncula. The mature peptide, with a length of 64 aa residues has a predicted pI of 9.24, and comprises the characteristic CSα β structural motif. Consequently, the S. domuncula ASABF shares high similarity with the nematode ASABFs; it is distantly related to the defensins. The recombinant peptide was found to display besides microbicidal activity, anti-fungal activity. In addition, the peptide lyses human erythrocytes. The expression of ASABF is upregulated after exposure to the apoptosis-inducing agent 2,2'-dipyridyl. During the process of apoptosis of surface tissue of S. domuncula, grazing gastropods (Bittium sp.) are attracted by quinolinic acid which is synthesized through the kynurenine pathway by the enzyme 3-hydroxyanthranilate 3,4-dioxygenase (HAD). Finally, the gastropods are repelled from the sponge tissue by the ASABF. It is shown that the effector peptide ASABF is sequentially expressed after the induction of the HAD gene and a caspase, as a central enzyme executing apoptosis.  相似文献   

Anti-proliferative activity of meroditerpenoids isolated from the brown alga Stypopodium flabelliforme against several cancer cell lines     

Pereira DM  Cheel J  Areche C  San-Martin A  Rovirosa J  Silva LR  Valentao P  Andrade PB 《Marine drugs》2011,9(5):852-862

The sea constitutes one of the most promising sources of novel compounds with potential application in human therapeutics. In particular, algae have proved to be an interesting source of new bioactive compounds. In this work, six meroditerpenoids (epitaondiol, epitaondiol diacetate, epitaondiol monoacetate, stypotriol triacetate, 14-ketostypodiol diacetate and stypodiol) isolated from the brown alga Stypopodium flabelliforme were tested for their cell proliferation inhibitory activity in five cell lines. Cell lines tested included human colon adenocarcinoma (Caco-2), human neuroblastoma (SH-SY5Y), rat basophilic leukemia (RBL-2H3), murine macrophages (RAW.267) and Chinese hamster fibroblasts (V79). Antimicrobial activity of the compounds was also evaluated against Staphylococcus aureus, Salmonella typhimurium, Proteus mirabilis, Bacillus cereus, Enterococcus faecalis and Micrococcus luteus. Overall, the compounds showed good activity against all cell lines, with SH-SY5Y and RAW.267 being the most susceptible. Antimicrobial capacity was observed for epitaondiol monoacetate, stypotriol triacetate and stypodiol, with the first being the most active. The results suggest that these molecules deserve further studies in order to evaluate their potential as therapeutic agents.  相似文献   

Resistance to late blight in foliage (Phytophthora infestans) of potatoes assessed as true seedlings and as adult plants in the glasshouse     

Helen E. Stewart  K. Taylor  R. L. Wastie 《Potato Research》1983,26(4):363-366

Summary True seedlings from crosses designed to produce progenies having high levels of field resistance to late blight (Phytophthora infestans (Mont.) de Bary) were scored in lots of 25 in a glasshouse. The results agreed with assessments subsequently obtained from plants grown from tubers from the same progenies when screened as individual whole plants in the glasshouse. The resistance of seedlings of both resistant and susceptible progenies was assessed by inoculating them 3–8 weeks after sowing. All were highly susceptible when inoculated at 3 weeks but resistance increased from 3 to 6 weeks and differed little between 6 and 8 weeks. The seedling test appears to provide a valid screen for resistance at an early stage in a breeding programme.  相似文献   

Antibacterial activity of marine and black band disease cyanobacteria against coral-associated bacteria     

Gantar M  Kaczmarsky LT  Stanić D  Miller AW  Richardson LL 《Marine drugs》2011,9(10):2089-2105

Black band disease (BBD) of corals is a cyanobacteria-dominated polymicrobial disease that contains diverse populations of heterotrophic bacteria. It is one of the most destructive of coral diseases and is found globally on tropical and sub-tropical reefs. We assessed ten strains of BBD cyanobacteria, and ten strains of cyanobacteria isolated from other marine sources, for their antibacterial effect on growth of heterotrophic bacteria isolated from BBD, from the surface mucopolysaccharide layer (SML) of healthy corals, and three known bacterial coral pathogens. Assays were conducted using two methods: co-cultivation of cyanobacterial and bacterial isolates, and exposure of test bacteria to (hydrophilic and lipophilic) cyanobacterial cell extracts. During co-cultivation, 15 of the 20 cyanobacterial strains tested had antibacterial activity against at least one of the test bacterial strains. Inhibition was significantly higher for BBD cyanobacteria when compared to other marine cyanobacteria. Lipophilic extracts were more active than co-cultivation (extracts of 18 of the 20 strains were active) while hydrophilic extracts had very limited activity. In some cases co-cultivation resulted in stimulation of BBD and SML bacterial growth. Our results suggest that BBD cyanobacteria are involved in structuring the complex polymicrobial BBD microbial community by production of antimicrobial compounds.  相似文献   

牛乳酪蛋白酶解物的分离纯化及抗菌肽乳基料的制备研究     

熊清权  李志成  童伟 《西北农林科技大学学报(自然科学版)》2013,41(1):200-206

【目的】分离纯化牛乳酪蛋白酶解物,检测酶解物及其分离组分的抑菌活性,并制备抗菌肽乳基料。【方法】从中性蛋白酶、碱性蛋白酶、胰蛋白酶及木瓜蛋白酶中筛选一种蛋白酶水解牛乳酪蛋白,将其酶解产物经大孔吸附树脂和凝胶过滤色谱分离、纯化后,以对大肠杆菌、沙门氏菌和金黄色葡萄球菌的抑菌圈直径、最小抑菌浓度(MIC)、最小杀菌浓度(MBC)为指标,分析酶解物和分离组分的抑菌活性。【结果】(1)木瓜蛋白酶水解牛乳酪蛋白4.5h,其酶解物对大肠杆菌、沙门氏菌和金黄色葡萄球菌均有较好的抑制作用。(2)大孔吸附树脂将牛乳酪蛋白酶解物分离成4个组分,其中以体积分数75%乙醇洗脱组分的抑菌作用较强。(3)凝胶过滤色谱将体积分数75%乙醇洗脱组分分离成4个色谱峰,其中A峰对大肠杆菌和沙门氏菌抑制作用较强,B峰对金黄色葡萄球菌抑制作用较强,A峰和B峰经冷冻干燥后成功制备了2种抗菌肽乳基料。【结论】牛乳酪蛋白酶解物经大孔吸附树脂和凝胶过滤色谱分离、纯化后,其分离组分的抑菌活性逐步增强,能够用于抗菌肽乳基料的制备。  相似文献   

Antimicrobial‐associated diarrhoea in three equine referral practices     

B. S. BARR  B. M. WALDRIDGE  P. R. MORRESEY  S. M. REED  C. CLARK  R. BELGRAVE  J. M. DONECKER  D. J. WEIGEL 《Equine veterinary journal》2013,45(2):154-158

Reasons for performing study: Although antimicrobial‐associated diarrhoea (AAD) is the most frequently observed adverse effect of antimicrobial therapy in horses, few multicentred studies on the prevalence of AAD have been performed. Objectives: To determine the prevalence of AAD in horses that developed diarrhoea after antimicrobial treatment for nondiarrhoeic conditions and identify the antimicrobials used. Methods: The 2009 database of 3 referral hospitals was searched to identify nonhospitalised horses (weanling age or older) treated with antimicrobials for nongastrointestinal conditions. Horses with these criteria that presented with diarrhoea during 2009 were included in the study. Additional information, including antimicrobial administered and results of faecal pathogen testing, was gathered on each hospitalised case. Results: Of the 5251 horses treated with antimicrobials for nongastrointestinal signs, 32 were diagnosed with probable AAD, a prevalence of 0.6% (95% confidence interval: 0.43–0.86%). The AAD‐diagnosed horses had an 18.8% (6/32) mortality rate. Horses with AAD had been treated for an average of 4.2 days. The most frequently used antimicrobials in horses with AAD were gentamicin in combination with penicillin (n = 7), enrofloxacin (n = 7) and doxycycline (n = 4). Clostridium difficile was identified in faecal samples from 4 horses, 2 of which died and Salmonella from 3 horses. Conclusions: Results indicated that the prevalence of AAD is low. Any antimicrobial class commonly used in equine practice is a potential cause of equine AAD. Other risk factors, such as opportunistic enteropathogens, may play a part in the development of diarrhoea secondary to antimicrobial usage. Potential relevance: Although the risk of equine AAD is low, this sequela of antimicrobial treatment is possible especially when opportunistic enteropathogens or other risk factors are present. Because drugs from any antimicrobial class can be potentially involved in AAD, clinicians have additional incentive to ensure the judicious use of antimicrobial agents.  相似文献