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重组体pET-28a-alkB/E.coli降解页岩油泥石油烃的功能研究
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作者 李雪菲 句泽林 +3 位作者 齐婷婷 郑乾璐 李喜梅 余丽芸 《山东化工》 CAS 2024年第19期239-243,共5页
为了降解页岩油泥中的石油烃,构建基因工程菌,表达石油烃降解关键酶以提高油泥的降解效果。以Pseudomonas qingdaonensis基因组为模板扩增alkB基因,连接至载体pET-28a,转化至E.coli BL21(DE3)中,SDS-PAGE和Western-blot鉴定表达的外源... 为了降解页岩油泥中的石油烃,构建基因工程菌,表达石油烃降解关键酶以提高油泥的降解效果。以Pseudomonas qingdaonensis基因组为模板扩增alkB基因,连接至载体pET-28a,转化至E.coli BL21(DE3)中,SDS-PAGE和Western-blot鉴定表达的外源蛋白。pET-28a-alkB/E.coli处理原油和页岩油泥,采用气相色谱法评估降解效果。发现alkB基因在大肠杆菌中能表达外源蛋白,且14 d原油及页岩油泥的降解率分别为47.5%和47.1%,表明重组体pET-28a-alkB/E.coli具备降解页岩油泥石油烃的功能。 展开更多
关键词 烷烃单加氧酶alkB 生物降解 e.coli BL21(DE3) 页岩油污泥 气相色谱法
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Exploring the modulatory role of bovine lactoferrin on the microbiome and the immune response in healthy and Shiga toxin‑producing E.coli challenged weaned piglets
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作者 Matthias Dierick Ruben Ongena +2 位作者 Daisy Vanrompay Bert Devriendt Eric Cox 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第3期1278-1291,共14页
Background Post-weaned piglets suffer from F18+Escherichia coli(E.coli)infections resulting in post-weaning diar-rhoea or oedema disease.Frequently used management strategies,including colistin and zinc oxide,have con... Background Post-weaned piglets suffer from F18+Escherichia coli(E.coli)infections resulting in post-weaning diar-rhoea or oedema disease.Frequently used management strategies,including colistin and zinc oxide,have contrib-uted to the emergence and spread of antimicrobial resistance.Novel antimicrobials capable of directly interacting with pathogens and modulating the host immune responses are being investigated.Lactoferrin has shown promising results against porcine enterotoxigenic E.coli strains,both in vitro and in vivo.Results We investigated the influence of bovine lactoferrin(bLF)on the microbiome of healthy and infected weaned piglets.Additionally,we assessed whether bLF influenced the immune responses upon Shiga toxin-producing E.coli(STEC)infection.Therefore,2 in vivo trials were conducted:a microbiome trial and a challenge infection trial,using an F18+STEC strain.BLF did not affect theα-andβ-diversity.However,bLF groups showed a higher relative abundance(RA)for the Actinobacteria phylum and the Bifidobacterium genus in the ileal mucosa.When analysing the immune response upon infection,the STEC group exhibited a significant increase in F18-specific IgG serum levels,whereas this response was absent in the bLF group.Conclusion Taken together,the oral administration of bLF did not have a notable impact on theα-andβ-diversity of the gut microbiome in weaned piglets.Nevertheless,it did increase the RA of the Actinobacteria phylum and Bifi-dobacterium genus,which have previously been shown to play an important role in maintaining gut homeostasis.Furthermore,bLF administration during STEC infection resulted in the absence of F18-specific serum IgG responses. 展开更多
关键词 e.coli Immune modulation LACTOFERRIN MICROBIOME
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Impact of an oligosaccharide-based polymer on the metabolic profiles and microbial ecology of weanling pigs experimentally infected with a pathogenic E.coli
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作者 Kwangwook Kim Cynthia Jinno +4 位作者 Xunde Li David Bravo Eric Cox Peng Ji Yanhong Liu 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第2期749-764,共16页
Background Our previous study has reported that supplementation of oligosaccharide-based polymer enhances gut health and disease resistance of pigs infected with enterotoxigenic E.coli(ETEC)F18 in a manner similar to ... Background Our previous study has reported that supplementation of oligosaccharide-based polymer enhances gut health and disease resistance of pigs infected with enterotoxigenic E.coli(ETEC)F18 in a manner similar to carbadox.The objective of this study was to investigate the impacts of oligosaccharide-based polymer or antibiotic on the host metabolic profiles and colon microbiota of weaned pigs experimentally infected with ETEC F18.Results Multivariate analysis highlighted the differences in the metabolic profiles of serum and colon digesta which were predominantly found between pigs supplemented with oligosaccharide-based polymer and antibiotic.The relative abundance of metabolic markers of immune responses and nutrient metabolisms,such as amino acids and carbohydrates,were significantly differentiated between the oligosaccharide-based polymer and antibiotic groups(q<0.2 and fold change>2.0).In addition,pigs in antibiotic had a reduced(P<0.05)relative abundance of Lachnospiraceae and Lactobacillaceae,whereas had greater(P<0.05)Clostridiaceae and Streptococcaceae in the colon digesta on d 11 post-inoculation(PI)compared with d 5 PI.Conclusions The impact of oligosaccharide-based polymer on the metabolic and microbial profiles of pigs is not fully understood,and further exploration is needed.However,current research suggest that various mechanisms are involved in the enhanced disease resistance and performance in ETEC-challenged pigs by supplementing this polymer. 展开更多
关键词 CARBADOX Colon microbiota Enterotoxigenic e.coli F18 Metabolomics Oligosaccharide-based polymer Weaned pigs
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Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso
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作者 Stéphanie Lynseh Carine Sita Bénao Dabiré Amana Métuor +7 位作者 Abdoul Karim Ouattara Rahimatou Yasmine Wendkouni Tiemtoré Nicolas Ouédraogo Blandine Ouédraogo Rhaina Olivia Badini Lionel Eliada Benoit Bambara Serge Sougué Jacques Simporé 《Open Journal of Applied Sciences》 2024年第4期881-892,共12页
Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales site... Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections. 展开更多
关键词 MULTIDRUG-RESISTANT CHICKEN OUAGADOUGOU Escherichia coli salmonella spp. Antibiotic
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Evaluating the Potential of Nitrofurantoin and Fosfomycin for E.coli UTIs: A Susceptibility Study
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作者 Usama Ahmed Muhammad Zubair +1 位作者 Baqaur Rehman Hafiz Muhammad Sultan 《Journal of Clinical and Nursing Research》 2024年第6期351-358,共8页
This study was designed to find the susceptibility of Nitrofurantoin and Fosfomycin among urinary isolates of Escherichia.coli.Four hundred(400)urine samples were collected for susceptibility of nitrofurantoin and fos... This study was designed to find the susceptibility of Nitrofurantoin and Fosfomycin among urinary isolates of Escherichia.coli.Four hundred(400)urine samples were collected for susceptibility of nitrofurantoin and fosfomycin among urinary isolates of E.coli.All indoor and outdoor patients'urinary samples yielded growth of E.coli.Mid-stream urine specimens were inoculated on blood agar and CLED agar and incubated at 35±2°C.Growth was observed,and Escherichia coli was identified by Gram staining,Catalase,Motility test and API 20E(Bio murex)as per standard procedure.Antimicrobial susceptibility testing of isolates for nitrofurantoin and fosfomycin was carried out by the modified Kirby-Bauer disc diffusion method according to CLSI guidelines ATCC 25922.E.coli was used as a quality control strain.A total of 400 samples were tested susceptibility of nitrofurantoin and fosfomycin among urinary isolates of E.coli during this period.A total of 400 samples yielded the growth of E.coli,out of which 178(44.5%)were male and 222(55.5%)were female samples.Among males,18(10%)were tolerant to nitrofurantoin,and 2(1.1%)were tolerant to fosfomycin.Among females,9(4.09%)were susceptible to nitrofurantoin while 6(2.72%)were susceptible to fosfomycin.Among age groups below 45 years old,6(4.76%)were tolerant to nitrofurantoin,and 2(1.58%)were sensitive to fosfomycin.Between 46-66 years old,4(2.81%)were sensitive to nitrofurantoin,and 3(2.11%)were sensitive to fosfomycin.Between 67-90 years old,17(12.87%)were sensitive to nitrofurantoin,and 4(3.03%)were tolerant to fosfomycin.Fosfomycin and nitrofurantoin showed good susceptibility in urinary isolates of E.coli and can be used empirically in our setup. 展开更多
关键词 e.coli FOSFOMYCIN NITROFURANTOIN SUSCEPTIBILITY Urinary isolates
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Effect of dietary fiber and threonine content on intestinal barrier function in pigs challenged with either systemic E.coli lipopolysaccharide or enteric Salmonella Typhimurium 被引量:4
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作者 Michael O.Wellington Kimberley Hamonic +3 位作者 Jack E.C.Krone John K.Htoo Andrew G.Van Kessel Daniel A.Columbus 《Journal of Animal Science and Biotechnology》 CAS CSCD 2020年第3期724-735,共12页
Background:The independent and interactive effects of dietary fiber(DF)and threonine(Thr)were investigated in growing pigs challenged with either systemic E.coli lipopolysaccharide(LPS)or enteric Salmonella Typhimuriu... Background:The independent and interactive effects of dietary fiber(DF)and threonine(Thr)were investigated in growing pigs challenged with either systemic E.coli lipopolysaccharide(LPS)or enteric Salmonella Typhimurium(ST)to characterise their effect on intestinal barrier function.Results:In experiment 1,intestinal barrier function was assessed via oral lactulose and mannitol(L:M)gavage and fecal mucin analysis in pigs challenged with E.coli LPS and fed low fiber(LF)or high fiber(HF)diets with graded dietary Thr.Urinary lactulose recovery and L:M ratio increased(P<0.05)during the LPS inoculation period in LF fed pigs but not in HF fed pigs.Fecal mucin output was increased(P<0.05)in pigs fed HF compared to LF fed pigs.In experiment 2,RT-qPCR,ileal morphology,digesta volatile fatty acid(VFA)content,and fecal mucin output were measured in Salmonella Typhimurium challenged pigs,fed LF or HF diets with standard or supplemented dietary Thr.Salmonella inoculation increased(P<0.05)fecal mucin output compared to the unchallenged period.Supplemental Thr increased fecal mucin output in the HF-fed pigs(Fib×Thr;P<0.05).Feeding HF increased(P<0.05)VFA concentration in cecum and colon.No effect of either Thr or fiber on expression of gene markers was observed except a tendency(P=0.06)for increased MUC2 expression with the HF diet.Feeding HF increased goblet cell numbers(P<0.05).Conclusion:Dietary fiber appears to improve barrier function through increased mucin production capacity(i.e.,goblet cell numbers,MUC2 gene expression)and secretion(i.e.,fecal mucin output).The lack of effect of dietary Thr in Salmonella-challenged pigs provides further evidence that mucin secretion in the gut is conserved and,therefore,Thr may be limiting for growth under conditions of increased mucin production. 展开更多
关键词 Barrier function e.coli lipopolysaccharide Fiber Goblet cells MUCIN salmonella Swine THREONINE
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Prevalence and Antimicrobial Susceptibility Patterns of Escherichia Coli and Salmonella Typhi Isolated from Meat and Fish Samples from Selected Markets in a Metropolis and District in Ghana
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作者 John Antwi Apenteng Nicholas Agyepong +6 位作者 Raymond Ashalley Tetteh Jonathan Asante Esther Eyram Asare Yeboah Tracy Turkson Emmanuel Sarpong Vera Ampomabea Akoto Theodora Sefa Danquah 《Advances in Infectious Diseases》 2023年第4期675-691,共17页
Antimicrobial resistance has become a major challenge to the treatment and prevention of infections resulted in high morbidity and mortality globally. The inappropriate or abuse of antibiotics in animal farming is a k... Antimicrobial resistance has become a major challenge to the treatment and prevention of infections resulted in high morbidity and mortality globally. The inappropriate or abuse of antibiotics in animal farming is a key factor and thus led to the emergence of bacteria resistance and subsequent transfer of resistance genes to humans through the food chain. This study was to determine the prevalence of Salmonella typhi (S. typhi) and Escherichia coli (E. coli) isolated from various meat and fish samples and their susceptibility patterns against five commonly used antibiotics in Ghana (Ciprofloxacin 5 μg, Amoxicillin-clavulanic acid 20/10 μg, Imipenem 10 μg, Tetracycline 30 μg and Ceftazidime 30 μg). A total of 105 meat and fish samples were obtained from Tema and Prampram markets and bacteria isolation was carried out using appropriate selective microbial culture media and various biochemical methods for identification. The susceptibility patterns were determined using the Kirby-Bauer disk diffusion method and the results were interpreted using the CLSI 2020 guidelines. The results revealed a total of 56 bacterial isolates comprising 14 E. coli (25%) and 42 S. typhi (75%) isolated from the meat and fish samples. The antibiogram study showed a high resistance rate (88.64%) of S. typhi isolates to amoxicillin-clavulanic acid and tetracycline (97.73%). A moderate susceptibility of the isolates was obtained with imipenem (53.27%). All the E. coli isolates were resistant to tetracycline (100%) and demonstrated 78.57% and 50% resistance to amoxicillin-clavulanic acid and ceftazidime respectively. A total of 78.57% of the E. coli isolates and 68.18% of S. typhi isolates showed multidrug resistance. The multiple antibiotic resistance (MAR) index for all the isolates ranged from 0.2 to 1.00 with two S. typhi isolates and one E. coli isolate having a MAR index of 1.00 signifying total resistance to all the 5 antibiotics tested. In conclusion, E. coli and S. typhi isolated from the meat samples exhibited high rate of resistance against the antibiotics tested and thus possesses a major health risk due to inappropriate use of antibiotics in animal and fish farming and possible transfer of resistant strains to humans. 展开更多
关键词 Antibiotic Resistance Escherichia coli salmonella typhi MEAT Fish
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Potential Risk of Transmission of Escherichia coli and Salmonella spp. Infections by the Musca domestica Fly and the Periplaneta americana Cockroach in the City of Cotonou (South Benin)
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作者 Tatcheme Filemon TatTokponnon Bidossessi Brunelle Ella Agassounon +8 位作者 Daton Sylvain Kougblenou Razak Osse Victorien Dougnon Calmette Nouwagbe Daga Justin Kossou Idayath Joachelle Gounou Yerima Festus Houessinon Sare Dabou Zoulkifilou Martin Akogbeto 《Advances in Microbiology》 2023年第9期448-461,共14页
Background: The occurrence of bacterial infections sometimes involves synanthropic flies and cockroaches, as mechanical vectors of pathogenic microorganisms. The aim of this study was to identify the different species... Background: The occurrence of bacterial infections sometimes involves synanthropic flies and cockroaches, as mechanical vectors of pathogenic microorganisms. The aim of this study was to identify the different species of flies and cockroaches that cohabit with humans in the city of Cotonou and determine the contribution of Musca domestica and Periplaneta americana in the transmission of bacteria responsible for infections in humans. Methods: Capture sessions during the day for flies and at night for cockroaches were carried out in 4 arrondissements of the city of Cotonou. The insects collected were transported to the Center of Research Entomological of Cotonou for identification, then sent to the Section Hygiene of Water and Food for microbiological analysis, enumeration and testing for human pathogenic bacteria. Results: A total of 351 flies and 26 cockroaches were collected at the sites, including two synanthropic species belonging to two families each. Musca domestica and Periplaneta americana were the most abundant species found after identification in the city of Cotonou. Thermo-tolerant coliforms and Escherichia coli were found on all specimens at varying concentrations. Salmonella spp. bacteria were identified in the fly population from the Dantokpa dump. Conclusion: Flies and cockroaches can transmit microorganisms to humans. The presence of Salmonella spp. among the specimens revealed that infections frequently caused by contaminated food or water are also transmitted to humans by flies. The presence of these germs on flies and cockroaches represents a potential risk of mechanical transmission to humans. It is, therefore, essential to continue investigations in order to assess the species of bacteria propagated, improve control strategies against these troublesome insects and adopt better hygiene conditions for better living. 展开更多
关键词 Musca domestica Periplaneta americana Mechanical Transmission salmonella spp. and Escherichia coli Infections Cotonou
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2种氟喹诺酮类抗生素与群体感应抑制剂对E.coli的联合毒性效应
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作者 赵远帆 张瑾 +2 位作者 曾健平 张静 张颖 《生态毒理学报》 CAS CSCD 北大核心 2023年第6期27-38,共12页
抗生素滥用带来严重的细菌耐药性,威胁生态环境和人体健康。群体感应抑制剂(quorum sensing inhibitors,QSIs)作为一种理论上难以引发细菌耐药性的新型潜在抗生素替代品,被建议单独使用或与传统抗生素联合使用。因此,考察抗生素与QSIs... 抗生素滥用带来严重的细菌耐药性,威胁生态环境和人体健康。群体感应抑制剂(quorum sensing inhibitors,QSIs)作为一种理论上难以引发细菌耐药性的新型潜在抗生素替代品,被建议单独使用或与传统抗生素联合使用。因此,考察抗生素与QSIs联合作用效应及其作用机理对其在环境中可能产生的联合暴露风险评估具有重要的参考意义。以应用较广泛的2种氟喹诺酮类药物氧氟沙星(ofloxacin,OFL)、左氧氟沙星(levofloxacin,LEV)和1种新型抗菌剂群体感应抑制剂4-羟基-2,5-二甲基-3(2H)呋喃酮(4-hydroxy-2,5-dimethyl-3(2H)-furanone,HDMF)为研究对象,运用直接均分法和均匀设计射线法分别设计3个二元和1个三元混合物体系,每个体系包含5条具有不同组分浓度比的射线。应用时间毒性微板分析法测定3种药物及其混合物体系对大肠杆菌(Escherichia coli,E.coli)的毒性,应用拟合归零法分析混合物的毒性相互作用及相互作用强度,采用分子间对接技术来探讨可能存在的作用机理。结果表明,HDMF、OFL、LEV对E.coli均具有浓度、时间依赖毒性,以半数效应浓度负对数为毒性指标,3种药物在同一暴露时间毒性顺序:LEV>OFL>HDMF。3种药物的二元混合物体系相互作用类型有拮抗/协同作用,而三元混合物体系的作用类型为协同作用,且作用类型和强度受混合物组分、暴露时间和浓度影响。氟喹诺酮类药物混合物体系中,因药物竞争结合蛋白点位而呈现出拮抗作用。在氟喹诺酮类药物和QSIs混合体系中,QSIs会破坏细菌的生物膜,使氟喹诺酮类药物更容易接触细菌造成损伤,从而呈现协同作用。但随着暴露时间的延长,氟喹诺酮类药物会对DNA造成损伤进而减少QSIs作用蛋白的产生,呈现出拮抗作用。 展开更多
关键词 氟喹诺酮类抗生素 群体感应抑制剂 e.coli 联合毒性 分子对接
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胶冻样芽孢杆菌对革兰氏阴性菌的抑菌活性及其抗菌次级代谢产物分析
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作者 李海利 徐引弟 +8 位作者 王治方 朱文豪 陈建豪 李斌 段进刚 冯丽丽 杨帆 马春江 闫祥洲 《河南农业科学》 北大核心 2024年第10期159-169,共11页
为筛选对革兰氏阴性菌抑菌活性较好的药用植物芍药的内生菌,采用表面消毒法和平板对峙法分离筛选对大肠杆菌和沙门氏菌有拮抗作用的芍药内生菌,对其进行形态学和分子生物学鉴定,并通过全基因组学分析探究其抗菌活性物质。结果表明,从芍... 为筛选对革兰氏阴性菌抑菌活性较好的药用植物芍药的内生菌,采用表面消毒法和平板对峙法分离筛选对大肠杆菌和沙门氏菌有拮抗作用的芍药内生菌,对其进行形态学和分子生物学鉴定,并通过全基因组学分析探究其抗菌活性物质。结果表明,从芍药根、茎、叶等不同组织分离得到20株内生菌。采用平板对峙法抑菌试验,从20株内生菌中获得1株抗菌效果较好的革兰氏阴性内生菌HNYJ291,经形态学和分子方法鉴定为胶冻样芽孢杆菌(Paenibacillus kribbensis),该菌能有效抑制大肠杆菌和沙门氏菌。对该菌进行全基因组测序分析,HNYJ291的基因组大小为5609136 bp,G+C含量为45.48%,预测其编码基因个数为4805个。分别有4779、3678、4027、3941、2994、2700个基因被NR、Swiss-Prot、Pfam、COG、GO、KEGG数据库注释,通过antiSMASH预测到与次级代谢产物合成相关的10个基因簇,主要次级代谢产物有环脂肽类抗生素(Fusaricidin B)、细菌素(Paenilan)、抗菌脂肽(Tridecaptin)、多黏菌素(Polymyxin)和抗菌肽(Paenicidin A)等。从其基因组中含有的抗菌活性物质相关基因簇可以预测出,该菌株具有开发新药和作为可饲用微生物的潜力。 展开更多
关键词 胶冻样芽孢杆菌 芍药 内生菌 沙门氏菌 大肠杆菌 抑菌效果 抗菌活性物质
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基于紫胶红素的靶标有色化免疫层析试纸条联检大肠杆菌O157∶H7和沙门氏菌
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作者 刘坤 王英林 +1 位作者 黄志强 刘箐 《工业微生物》 CAS 2024年第3期104-110,共7页
为摆脱免疫层析试纸条对配对抗体的依赖,文章设计了一种新型靶标有色化免疫层析试纸条,使用紫胶红素和十二合水硫酸铝钾媒染剂,通过先媒后染的方法,实现了免疫层析试纸条的“可视化”。验证结果显示,该试纸条对大肠杆菌O157∶H7和沙门... 为摆脱免疫层析试纸条对配对抗体的依赖,文章设计了一种新型靶标有色化免疫层析试纸条,使用紫胶红素和十二合水硫酸铝钾媒染剂,通过先媒后染的方法,实现了免疫层析试纸条的“可视化”。验证结果显示,该试纸条对大肠杆菌O157∶H7和沙门氏菌的检测限均达到了106 CFU/mL;同时,与常见食源性致病菌间不存在交叉反应,在鸡胸肉、鸡蛋、牛奶等食品基质中能够在增菌9 h内检出。文章成功设计了一种操作简单、检测成本低,更易国产化的快速检测免疫层析试纸条,为后续免疫层析试纸条的设计提供了新思路。 展开更多
关键词 大肠杆菌O157∶H7 沙门氏菌 紫胶红素 靶标有色化 免疫层析试纸条
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4种常见食源性病原菌多重PCR检测技术研究
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作者 王珊 王雁伟 +1 位作者 高辉明 艾鹏飞 《河北工业科技》 CAS 2024年第2期133-140,共8页
为了解决常规方法检测食源性病原菌存在操作繁琐、周期长的问题,基于4种常见食源性病原菌特异基因序列扩增提出了一种快速、高效的多重PCR(multiplex polymerase chain reaction, MPCR)检测方法。根据单增李斯特菌iap基因、蜡样芽孢杆菌... 为了解决常规方法检测食源性病原菌存在操作繁琐、周期长的问题,基于4种常见食源性病原菌特异基因序列扩增提出了一种快速、高效的多重PCR(multiplex polymerase chain reaction, MPCR)检测方法。根据单增李斯特菌iap基因、蜡样芽孢杆菌gyrB基因、产志贺毒素大肠埃希氏菌stxⅠ基因、肠炎沙门氏菌invA基因的特异序列分别设计引物后建立MPCR反应体系,测试其特异性、敏感性和可行性,并与国标培养法进行比较。结果表明:MPCR扩增出4个目标基因的特异性条带大小依次为371、221、432、171 bp;在58℃的退火温度下,MPCR扩增表现出良好的特异性,无非特异性扩增,4种病原菌最低检出限达到102CFU/mL;MPCR方法和国标培养法对多种食源性病原菌感染的牛奶样品的检测结果完全一致,检测周期由原来的5~7 d缩减到8~9 h。所建立的MPCR技术作为一种快速、高效的检测方法,可为食品安全生产提供保障。 展开更多
关键词 食品检验学 多重PCR(MPCR) 单增李斯特菌 蜡样芽孢杆菌 产志贺毒素大肠埃希氏菌 肠炎沙门氏菌
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重组E.coli工程菌高密度培养生产人源型胶原蛋白 被引量:66
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作者 范代娣 段明瑞 +4 位作者 米钰 宋纪蓉 惠俊峰 王德伟 王国柱 《化工学报》 EI CAS CSCD 北大核心 2002年第7期752-754,共3页
Several technical parameters were studied during the fermentation of recombinant E.coli for the production of collagen-like biopolymer.The effects of dissolved oxygen as well as glucose concentration on fermentation w... Several technical parameters were studied during the fermentation of recombinant E.coli for the production of collagen-like biopolymer.The effects of dissolved oxygen as well as glucose concentration on fermentation were observed.The OD 600 value could reach 98 when dissolved oxygen was controlled at 50% and glucose around 1%.The production of human-like collagen with a yield of 29.4% was obtained. 展开更多
关键词 重组e.coli工程菌 高密度发酵 类人胶原蛋白 培养工艺 发酵
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养殖场空气中E.coli磺胺类抗生素的抗性 被引量:14
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作者 金明兰 孟庆玲 +7 位作者 赵玉鑫 徐莹莹 薛洪海 齐子姝 李娜 沈梦楠 孙世梅 金宁一 《环境化学》 CAS CSCD 北大核心 2017年第3期472-479,共8页
本文从养殖场空气中分离出360株E.coli(大肠杆菌,Escherichia coli),应用肉汤微量稀释法和PCR方法,分离磺胺甲唑敏感菌株,检测抗生素抗性和抗性基因.在分离的E.coli中,对磺胺甲唑敏感菌株为95株(26.4%),有48株含有青霉素、氯霉素、四环... 本文从养殖场空气中分离出360株E.coli(大肠杆菌,Escherichia coli),应用肉汤微量稀释法和PCR方法,分离磺胺甲唑敏感菌株,检测抗生素抗性和抗性基因.在分离的E.coli中,对磺胺甲唑敏感菌株为95株(26.4%),有48株含有青霉素、氯霉素、四环素、环丙沙星、庆大霉素和利福平的抗性,而47株未含有抗性.其中,7株菌株含有1种抗生素抗性、11株菌株含有2种抗生素抗性、17株菌株含有3种抗生素抗性、6株菌株含有4种抗生素抗性、4株菌株含有5种抗生素抗性、3株菌株含有6种抗生素抗性.对抗生素的耐受能力依次为:氯霉素、青霉素、四环素、环丙沙星、庆大霉素、利福平.磺胺甲唑敏感菌株共检出163个抗性基因,sul1、int1、sul2、Int2、sul3检出数量依次为49、44、29、20和19;含一种、二种、三种、四种、五种抗性基因菌株分别为45、22、10、7、2;但有6株未检测出抗性基因.结果表明养殖场建场时间、抗生素使用、养殖规模等与抗生素抗性菌的抗性呈正相关;养殖场空气中分离的E.coli抗生素抗性较高,且具有多重抗性;抗生素抗性的表现型与其基因型之间出现不完全吻合现象. 展开更多
关键词 磺胺类抗性菌 抗性基因 e.coli 养殖场空气
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秦皇岛地区狐源致病性E.coli对四环素类药物耐药性和耐药基因的检测 被引量:7
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作者 张召兴 李蕴玉 +4 位作者 贾青辉 张香斋 张艳英 耿田田 李佩国 《河北科技师范学院学报》 CAS 2016年第2期55-58,共4页
为了确定秦皇岛地区狐源大肠杆菌(E.coli)对四环素类药物的耐药性和耐药基因分布,采用常规的鉴定方法,从不同养狐场送检的腹泻的狐狸体内分离鉴定出20株E.coli。致病性试验表明,该菌为致病性E.coli。药敏试验结果表明:分离菌株对四环素... 为了确定秦皇岛地区狐源大肠杆菌(E.coli)对四环素类药物的耐药性和耐药基因分布,采用常规的鉴定方法,从不同养狐场送检的腹泻的狐狸体内分离鉴定出20株E.coli。致病性试验表明,该菌为致病性E.coli。药敏试验结果表明:分离菌株对四环素和强力霉素药率分别达到95%和90%。通过PCR方法检测分离菌株四环素类药物的耐药基因,结果显示,tet A和tet B基因的检出率分别为100%和95%。本研究为秦皇岛地区防治狐源致病性大肠杆菌病提供实验基础。 展开更多
关键词 狐狸 e.coli 四环素 PCR 耐药基因 秦皇岛地区
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中药三黄汤、小檗碱对E.coli生长抑制作用与庆大霉素的比较 被引量:13
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作者 刘玉庆 张玉忠 +2 位作者 刘胜贵 金建玲 高培基 《应用与环境生物学报》 CAS CSCD 2003年第3期302-306,共5页
庆大霉素对E .coli的抑菌作用强 ,试管稀释法、琼脂稀释法和平板抑菌圈法抑菌试验得到一致的MIC(3~5 μg/mL) ;三黄汤、小檗碱抑菌作用弱而稳定 ,试管稀释法测得的MIC分别为 5 0 0mg/mL和 2 .5mg/mL ,而用平板抑菌圈法得不到明显的抑菌... 庆大霉素对E .coli的抑菌作用强 ,试管稀释法、琼脂稀释法和平板抑菌圈法抑菌试验得到一致的MIC(3~5 μg/mL) ;三黄汤、小檗碱抑菌作用弱而稳定 ,试管稀释法测得的MIC分别为 5 0 0mg/mL和 2 .5mg/mL ,而用平板抑菌圈法得不到明显的抑菌圈 .在亚MIC药物液体分批培养时 ,庆大霉素抑菌曲线起初 2h迅速下降 ,而后回升到初始浓度 ,而三黄汤抑菌曲线平缓稳定 ,说明中药和抗生素的抑菌机制明显不同 .庆大霉素与小檗碱混合使用时 ,与庆大霉素单独使用相近 ,而与三黄混合使用时 ,则主要表现三黄汤的抑菌作用 .因此中西药结合时需要慎用 .在接近MIC药物培养基中连续传代 2 0次后 ,庆大霉素MIC提高 8倍多 ,而三黄汤和小檗碱MIC无显著变化 ,无抗药性产生 ,也不产生对庆大霉素的交叉抗药性 .研究结果还表明 ,在 1/ 4MIC三黄汤中连续传代 2 0次 ,能消除E .coli已形成的庆大霉素抗性 ,这为解决抗生素抗药性提供了线索 .图 4参 2 展开更多
关键词 中药 三黄汤 小檗碱 e.coli 生长抑制作用 庆大霉素 抑菌作用 抗药性
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4种鸭源细菌的分离鉴定及耐药性分析
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作者 李悦林 肖奇奇 +5 位作者 罗丽娜 杨婧婧 丁鸿飞 黄涵 刘辉鑫 李德龙 《动物医学进展》 北大核心 2024年第9期123-126,共4页
为了解重庆市潼南区鸭场细菌性感染情况,从不同鸭场收集15只病鸭,剖检并无菌取其大脑进行细菌分离,对分离的细菌进行体外培养、革兰氏染色、16S rDNA鉴定以及耐药性分析。结果显示,剖检可见鸭体腔内有严重黄白色纤维素性渗出,心脏与肝... 为了解重庆市潼南区鸭场细菌性感染情况,从不同鸭场收集15只病鸭,剖检并无菌取其大脑进行细菌分离,对分离的细菌进行体外培养、革兰氏染色、16S rDNA鉴定以及耐药性分析。结果显示,剖检可见鸭体腔内有严重黄白色纤维素性渗出,心脏与肝脏表面均有一层黄白色纤维素性假膜;从15只病鸭中共分离出4种5株细菌,1株沙门氏菌、1株奇异变形杆菌、1株葡萄球菌和2株大肠埃希氏菌;4种细菌均表现出了不同程度的多重耐药性,其中沙门氏菌多重耐药现象最为严重,表现为11重耐药性。说明实际临床中养鸭场细菌性感染情况复杂,应加强鸭细菌性疾病相关防治措施。 展开更多
关键词 大肠埃希氏菌 沙门氏菌 奇异变形杆菌 葡萄球菌 分离鉴定
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来自腹泻合并急性肾衰病人疫区的99株E.coli O157∶H7的鉴定结果分析 被引量:3
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作者 夏胜利 张锦 +1 位作者 陈振东 郭秋生 《疾病监测》 CAS 2002年第12期448-452,共5页
目的调查研究河南省2000年3月17日-7月6日发生的腹泻合并急性肾衰病人的致病菌。方法采集病人、外环境、家畜和家禽标本620份,采用免疫磁珠集菌法、CHROMAGAR-O157∶H7显色培养基分离及营养肉汤增菌、rfbO157、rfbO111引物多重PCR扩增... 目的调查研究河南省2000年3月17日-7月6日发生的腹泻合并急性肾衰病人的致病菌。方法采集病人、外环境、家畜和家禽标本620份,采用免疫磁珠集菌法、CHROMAGAR-O157∶H7显色培养基分离及营养肉汤增菌、rfbO157、rfbO111引物多重PCR扩增等方法进行病原菌的检测。结果分离出99份E.coli O157∶H7菌株,其中rfbO157、志贺氏样毒素2(stx2)、溶血素(hlyA)、肠上皮细胞纤毛消除素(eaeA)基因和vero细胞毒性试验均阳性的有56株,其它基因组合7株,36株无毒力基因。结论99株E.coli O157∶H7在CHROMAGAR-O157∶H7显色培养基生长形态、颜色,生化反应及毒力基因表现等方面出现多样化,对于今后在制定对该菌的诊断标准、传染源的控制及细菌毒力学等方面的研究提供了依据。 展开更多
关键词 腹泻 急性肾衰 合并症 致病菌 e.coli O157:H7 免疫磁珠 多重PCR 毒力基因
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低能离子注入E.coli K12的HRS/IRR效应及recA基因在其诱发中的作用 被引量:4
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作者 杨天佑 李培睿 +2 位作者 田静 李宗伟 秦广雍 《原子核物理评论》 CAS CSCD 北大核心 2008年第4期397-401,共5页
以MG1655(野生型),LE392(recA-)和DH5α(recA-)3株E.coliK12菌株为材料,研究了30keVN+离子注入E.coliK12时HRS/IRR效应的诱发情况及recA基因在其诱发中的作用。结果显示:小于10×1014ions/cm2低剂量离子注入大肠杆菌可诱发HRS/IRR效... 以MG1655(野生型),LE392(recA-)和DH5α(recA-)3株E.coliK12菌株为材料,研究了30keVN+离子注入E.coliK12时HRS/IRR效应的诱发情况及recA基因在其诱发中的作用。结果显示:小于10×1014ions/cm2低剂量离子注入大肠杆菌可诱发HRS/IRR效应;30keVN+离子注入MG1655,LE392菌株都可诱发HRS/IRR效应,而在DH5α菌株中无法诱导IRR效应。recA-与HRS/IRR效应相斥性表明recA基因在HRS/IRR效应的诱发中发挥了重要作用。 展开更多
关键词 HRS/IRR N^+ 注入 e.coli K12 RECA
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过量表达苹果酸酶对E.coli FMJ39厌氧混合酸发酵的影响 被引量:7
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作者 姜岷 谢鑫 +1 位作者 许琳 严明 《中国生物工程杂志》 CAS CSCD 北大核心 2007年第1期69-74,共6页
为了考察苹果酸酶对厌氧混合酸发酵的影响,从E.coliDH5α中PCR扩增苹果酸酶(NAD+-dependent,E.C1.1.1.38)基因sfcA,插入质粒pTrc99a构建了表达质粒pTrc99a-sfcA,有氧和厌氧的条件下,IPTG诱导在E.coliFMJ39(ldh,pfl)中均获得大量表达。... 为了考察苹果酸酶对厌氧混合酸发酵的影响,从E.coliDH5α中PCR扩增苹果酸酶(NAD+-dependent,E.C1.1.1.38)基因sfcA,插入质粒pTrc99a构建了表达质粒pTrc99a-sfcA,有氧和厌氧的条件下,IPTG诱导在E.coliFMJ39(ldh,pfl)中均获得大量表达。厌氧发酵结果表明,过量表达苹果酸酶会影响混合酸发酵中甲酸、乙酸、丁二酸途径。重组菌甲酸和乙酸的量分别比受体菌提高了17.58%和15.27%,丁二酸的量降低了26.87%,柠檬酸的量变化不大。实验证实即使pfl基因缺陷,高浓度的L-Thr和L-Ser也会诱导Tdc操纵元把丙酮酸转化为甲酸和乙酸。 展开更多
关键词 苹果酸酶 e.coli FMJ39 厌氧发酵 混合酸发酵 有机酸
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