Pathogenic effects of biofilm with chronic pseudomonas aeruginosa lung infection in rats

Objective： To establish an animal model of P.aeruginosa biofilm associated with chronic pulmonary infection and investigate the pathogenic effects of biofilm. Methods： Experiments in vitro, measuring the MICS, MBCS of levofloxacin（LFX）, ceftazidime（CAZ） in PAO579 in alginate beads and planktonic PAO579. Rats were challenged with 0.1 ml of PAO579（109CFU/ml） in alginate beads or 0.1 ml of planktonic PAO579（109CFU/ml）, 3,7,14 days after challenging, bacteriological, pathological features were observed. Results： The MICS, MBCS of LFX, CAZ in PAO579 in alginate beads were higher than those in planktonic PAO579 in vitro. CFU/lung in alginate beads group was significantly higher than that in planktonic bacteria group（P = 0.002, P = 0.004, P = 0.002, respectively）; macroscopic lung pathology and the inflammation in alginate beads group were significantly more severe compared to those in planktonic bacteria group in vivo. Conclusion： P.aeruginosa biofilm protected bacterium from killing of antibiotics and might mediate the host immune damage in the lung tissue and made bacterium evade the host immune defense.

Tracking Survey of Immune Effects of Highly Pathogenic Porcine Reproductive and Respiratory Syndrome (HP-PRRS) in Changping District, Beijing City

The epidemiology of highly pathogenic porcine reproductive and respiratory syndrome( HP-PRRS) in Changping District,Beijing City was investigated from 2010 to 2015. Through statistics of vaccine,immune procedure and antibody levels,the epidemic prevention effect of HP-PRRS in Changping District was scientifically assessed.

Pathogenic effects of O-polysaccharide from Shigella flexneri strain

AIM To investigate the specific pathogenesis ofO-polysaccharide (O--PS) which is on the outermembrane of lipopolysaccharides (LPS) fromShigella fi^eri.METHODS The O--PS was isolated and purifiedfrom Shigella nexneri 5 MgoT by enzymatichydrolysis and gel chromatography. Effects ofO--PS were observed by in vitro experiment,(HeLa cell Culture ), and in vivo experiment(rabbit lieal loop assay).RESULTS ID vitro and in vivo e-cP6riments withthe purified O--PS from Shigells flexnefi revealedthat the O--PS alone was toxic to Hela cells andcaused mucosal inflammation and hemorrhagicexudation in lieal loop of rabbit.DISCUSSION O--PS might b6 one of the factorscausing diarrhea and its mechanism wasdifferent from endotoxin reaction of LPS. Themolecular mechanism of O-PS need furtherstudies.

Synergistic Effect of Combined Antibiotics against Some Selected Multidrug Resistant Human Pathogenic Bacteria Isolated from Poultry Droppings in Akure, Nigeria

Antibiotic resistant bacteria pass between humans, between animals and between humans and animals in both directions, the use of antibiotics in poultry has contributed to multiple antibiotic resistant in pathogenic bacteria and use of two antibiotics might prevent the emergence of resistance to either. In this study, synergistic effect of combined antibiotics against multidrug resistant human pathogenic bacterial isolates from poultry droppings in Akure, Nigeria was examined. Collection of samples, isolation and identification of bacteria were carried out using standard microbiological method, antibiotic sensitivity test was performed by disc diffusion method and zone of inhibition was used to interpret the sensitivity test as resistant, susceptible or intermediate while combined effects of two antibiotics were investigated by macrobroth dilution and checkerboard assay methods while the synergetic effects of combined antibiotics were calculated using Fractional Inhibitory Concentration (FIC) and percentage synergistic interaction was calculated. All the ten (10) species of bacterial isolates were multidrug resistant and are less resistant to ofloxacin. The highest percentage synergistic interactions observed were Ofloxacin + Amoxicillin (90%), Ciprofloxacin + Amoxicillin (90%), Tetracycline + Amoxicillin (70%), Tetracycline + Augmentin (80%), Cotrimoxazol + Amoxicillin (50%), Cotrimoxazol + Augmentin (70%), Chloramphenicol + Amoxicillin (70%) and Chloramphenicol + Augmentin (80%). Poultry droppings is a potential source of human pathogenic bacteria, high frequency of multiple antibiotic resistance bacteria observed in this study is of great treat to man as this may cause the treatment of infection caused by these bacteria to be difficult. Combination of beta-lactam antibiotic with fluoroqunolones, tetracycline, Chloramphenicol and Cotrimoxazole was synergetic and this will reduce dose related toxicity and prevent resistance to single antibiotic.

Development and evaluation of a herbal formulation with antipathogenic activities and probiotics stimulatory effects

Searching alternative feed antibiotics is always a study hotspot in the field of animal production. In this study, the antipathogenic activities and probiotics stimulatory effects of 30 kinds of herbs were screened through Oxford cup method and Hungate roll method. 15 herbs showed significantly antibacterial activities（P〈0.05） against Escherichia coli, Salmonella enteritidis, Salmonella typhimurium and Staphylococcus aureus. Seven herbs showed greatly stimulatory promoting effects on Lactobacillus acidophilus and Bifidobacterium longum. Finally, five herbs were combined for the developed formulation with selective antibacterial properties and they were Mume Fructus（35%）, Isatidis Folium（25%）, Moslae Herba（20%）, Chrysanthemi Indici Flos（13%） and Bupleuri Radix（7%）. The herbal formulation showed significantly antibacterial abilities against four pathogens and stimulatory promoting abilities on two probiotics in vitro and the equivalent activities in broiler chickens in vivo against E. coli and L. acidophilus. The toxicity study showed it had no toxicity, which indicated that it would be a kind of preferred candidate for an alternative antibiotic in future animal production.

Drug Sensitive Test on Main Pathogenic Bacteria of Cow Recessiveness Mastitis Using Traditional Chinese Medicine Preparation “Zengrujianniusan”

According to the theory of Chinese veterinary medicine and characteristics of Chinese herbal medicine, four different preparations of compound Chinese medicine ＂Zengrujianniusan＂ were composed, and the prepared water decoction was used to carry on the bacteriostatic test on main pathogens of cow recessiveness mastitis. The results showed that the four different prescriptions of water decoction all had antibacterial effects. The prescription 3 was sensitive to Staphylococcus aureus and Streptococcus agalactiae, while the other three prescriptions showed high sensitivity, and the prescription 3 had the strongest bacteriostatic effects.

Use of <i>Lactococcus lactis</i>Subsp. <i>Lactis</i>Strains to Inhibit the Development of Pathogens

Bovine mastitis affects the udder health and thus causing significant economic losses. Probiotic products based on the use of lactic acid bacteria (LAB) to limit pathogens multiplication and pre-infection risks can be an interesting alternative to post infection allopathic treatment with antibiotics. Lactococcus lactis is one of the most important bacteria used in dairy technology. In this work, a total of 21 Lactococcus lactis subsp. Lactis strains, 20 from goat milk whey and one strain from cow milk were used to evaluate their antibacterial activity against four pathogenic germs responsible for mastitis: Escherichia coli, Staphylococcus aureus, Streptococcus uberis and Streptococcus agalactiae. The nisin-producing cow milk strain was active against St. uberis and Str. Agalactiae using the well diffusion method. For the strains isolated from goat milk whey, no antimicrobial effect was observed against these pathogens. However, a different approach based on the growth of pathogenic bacteria interacting with the Lactococcus lactis strains in a minimum medium was used to study the barrier effect of LAB. The Lactococcus lactis strains S1 and S2 from goat milk whey depleted the growth of Sa. aureus, St. uberis and E. coli during 8 h and stopped the development of St. agalactiae.

Meta-analysis of clinical effect of clearing heat and cooling blood on psoriasis and its effect on inflammatory cytokines

Objective:To evaluate the effect of Qingreliangxue method compared with Acitretin Capsules on clinical efficacy of psoriasis and serum inflammatory cytokines.Methods:The computer searches databases such as CNKI,Wanfang,VIP,PubMed,Embase and Cochrane Library.The search time is from the time the library is built until December 2019.According to the criteria for screening and selection of studies,extract data,use risk assessment tools for quality evaluation,and use Revman 5.3 software to perform meta-analysis on the outcome indicators of the included studis.Results:Finally,20 studies were included,with a total of 1592 patients.The analysis results showed that the total effective rate(OR=3.70,95%CI[2.58,5.30],P<0.00001)and cure rate(OR=2.40,95%CI[1.86,3.10],P<0.00001),PASI score(OR=-2.65,95%CI[-3.60,-1.70],P<0.00001),serum inflammatory cytokines(OR=-8.84,95%CI[-10.52,-7.16],P<0.00001),adverse reactions(OR=0.25,95%CI[0.11,0.57],P=0.001)are superior to Acitretin Capsules.Statistics of the top 10 Chinese medicines in clinical used frequency are,in order,habitat,red peony root,paeonol,honeysuckle,comfrey,soil tuckahoe,salvia miltiorrhiza,buffalo horn,heliotrope,angelica.Conclusion:Based on the current evidence,the treatment of psoriasis with clearing heat and cooling blood as the mainstay of Chinese medicine alone or in combination with Acitretin Capsules can better improve the efficacy,and its mechanism may be related to reducing inflammation.Due to the limitation of the included literature,this conclusion needs to be further verified.

应用综合干预措施对促进住院患者抗菌药物治疗前病原学送检的效果评价

目的探讨应用综合干预措施对促进住院患者抗菌药物治疗前病原学送检的效果。方法选取2020年1月—2021年12月某三甲医院治疗性使用抗菌药物的住院患者为研究对象,2021年1月开始实施综合干预措施,比较干预前组(2020年1—12月)和干预后组(2021年1—12月)抗菌药物治疗前病原学送检率、送检分类和重点监管科室送检率。结果共纳入治疗性使用抗菌药物的住院患者10239例,其中干预前组4526例,干预后组5713例。干预后的抗菌药物治疗前、限制级抗菌药物治疗前、特殊级抗菌药物治疗前病原学送检率分别为94.56%、94.72%、96.03%,高于干预前的83.74%、84.47%、84.95%,差异均有统计学意义(均P<0.05)。干预后的指向性病原体送检率为64.87%,高于干预前的28.04%,差异均有统计学意义(均P<0.05)。干预后的重症医学科、呼吸与危重症医学科、儿科、神经外科和普通外科治疗性使用抗菌药物病原学送检率分别为93.20%、91.17%、92.20%、94.12%、91.15%,高于干预前的85.00%、82.19%、83.20%、83.33%、83.03%,差异均有统计学意义(均P<0.05)。结论应用综合干预措施可提高住院患者抗菌药物治疗前病原学送检率,应密切关注医院感染诊断相关病原学送检指标和无菌体液送检指标。

4种消毒剂对规模化奶牛场常见病原菌消毒效果的评价

试验旨在探讨常见消毒剂对规模化奶牛场环境气载和动物体表优势病原菌的杀灭效果,为进一步制定科学合理的消毒技术规范提供参考。研究以优势病原菌(金黄色葡萄球菌、大肠杆菌、产气荚膜梭菌)为指示菌,通过悬液定性和定量试验探讨常见消毒剂(安灭杀、辉胜-30、过硫酸氢钾、聚维酮碘)对细菌繁殖体的杀灭效果。结果显示,1∶100倍稀释的安灭杀消毒液作用1、20及5 min能够有效杀灭金黄色葡萄球菌、产气荚膜梭菌和大肠杆菌;1∶200倍稀释的辉胜-30消毒液作用10、20及15 min能够有效杀灭金黄色葡萄球菌、产气荚膜梭菌和大肠杆菌;1∶200倍稀释的过硫酸氢钾消毒液作用3、5、5 min能够有效杀灭金黄色葡萄球菌、产气荚膜梭菌和大肠杆菌;1∶400倍稀释的聚维酮碘消毒液作用15、20、20 min能够有效杀灭金黄色葡萄球菌、产气荚膜梭菌和大肠杆菌。研究表明,金黄色葡萄球菌和大肠杆菌对安灭杀消毒液敏感,产气荚膜梭菌对过硫酸氢钾复合物粉较敏感,4种消毒剂宜交替使用可避免耐药性菌株的产生。

精氨酸对引起采后蓝莓腐烂的链格孢靶标菌的抑制效果研究

目的旨在筛选引起蓝莓采后腐烂的链格孢靶标菌株,并比较L-精氨酸和山梨酸钾对其抑制效果,为蓝莓采后链格孢腐烂病的防控提供前期基础。方法通过组织分离法结合单孢分离法进行致腐菌的分离,采用ITS序列分析进行属水平鉴定,采用ATP序列分析结合形态学观察进行种水平鉴定,采用平板抑菌法比较L-精氨酸和山梨酸钾的抑菌效果。结果本研究分离获得的链格孢菌均有致病性,分别属于3个不同种群,分别为细极链格孢(Alternaria tenuissima)、互隔交链孢(A.alternata)和云南铁杉链格孢(A.dumosa)。以菌株B20190623E3(A.tenuissima代表菌株)、菌株B20190623B1(A.alternata代表菌株)、菌株B20190623C1(A.dumosa代表菌株)为靶标菌,发现L-精氨酸对供试3株靶标菌的EC50值均低于山梨酸钾。结论供试链格菌株均有致病性,其中引起蓝莓采后腐烂的优势链格孢种群为细极链格孢。云南铁杉链格孢为引起蓝莓果实腐烂的新纪录种。筛选获得了3株链格孢代表靶标菌。L-精氨酸对引起蓝莓采后腐烂的链格孢菌具有较好的抑制效果。

维氏气单胞菌弱毒株FS12001及其疫苗对异育银鲫的免疫效果

为探究由维氏气单胞菌(Av)弱毒株FS12001制备的疫苗免疫效果,将Av弱毒株FS12001制备活疫苗、灭活疫苗、ISA763A-灭活疫苗和蜂胶-灭活疫苗,腹腔注射免疫异育银鲫,同时设ISA763A佐剂、蜂胶佐剂及0.65%NaCl作为对照组。于免疫后1、3、5、7和14 d经实时荧光定量PCR(qRT-PCR)检测脾脏组织中IgM、IL-1β及LZM的基因表达量;于免疫后7、14、21、28、42和48 d尾静脉采血分离血清,检测IgM抗体水平,测定SOD和LZM酶活性;于免疫28 d后用2株Av强毒株分别攻毒各组实验鱼,连续观察记录7 d,计算各免疫组的相对保护率。结果显示,各免疫组脾脏组织中IgM、IL-1β及LZM的基因表达量高于对照组,且ISA763A-灭活疫苗组和蜂胶-灭活疫苗组的表达量显著高于其他各实验组。各疫苗免疫组血清特异性抗体水平均显著高于0.65%NaCl对照组和佐剂对照组。各疫苗免疫组的LZM活性均在28 d最高,灭活疫苗组、ISA763A-灭活疫苗组及蜂胶-灭活疫苗组SOD活性均在7 d最高。菌株AVCA07攻毒后,活疫苗组、灭活疫苗组、ISA763A-灭活疫苗组和蜂胶-灭活疫苗组的RPS分别为63%、56%、100%和56%;菌株YC170511攻毒后,以上4个免疫组RPS分别为59%、55%、93%和72%。研究表明,用弱毒株FS12001制备疫苗,注射免疫异育银鲫后均可增加脾脏中IgM、IL-1β及LZM的基因表达量,提高血清抗体水平,增强SOD和LZM酶活性,增强其抵抗Av感染的能力。

12种中药材浸提物对苹果主要病害病原的毒力及防效

为探索中药材防治5种苹果主要真菌病害的应用价值,采用菌丝生长速率法,对供试的12种中药材浸提物进行室内毒力测定,并开展强抑菌作用的中药材浸提物的病害田间防治试验。结果表明,土荆皮Pseudolarix amabilis浸提物对苹果轮纹病菌Botryosphaeria dothidea、霉心病菌Trichothecium roseum、炭疽病菌Glomerella ciningularia、斑点落叶病菌Alternaria alternata、苹果树腐烂病菌Valsa mali的抑菌活性较强,EC_(50)分别为0.91、1.98、0.65、0.81、0.95 g/L。混配后,12种中药材等量混配浸提物对苹果树腐烂病菌、轮纹病菌、霉心病菌增效作用最强,增效系数分别为2.71、4.43、16.21。田间防治试验中,土荆皮浸提物对苹果斑点落叶病防效为54.10%;刮除苹果枝干轮纹病瘤后,土荆皮浸提物对苹果轮纹病防效达54.78%。本研究明确了土荆皮及其与其他中药材混配的浸提物对苹果主要病害病原具有良好的室内抑菌作用,土荆皮浸提物在田间也表现出进一步开发为植物源杀菌剂的潜力。

莱氏绿僵菌Mr006鉴定及对草地贪夜蛾致病力

收集草地贪夜蛾致病性莱氏绿僵菌,丰富昆虫病原真菌资源,为草地贪夜蛾绿色防控生防制剂开发提供依据。采用形态学和ITS-r DNA序列分析相结合的方法对菌株Mr006进行了鉴定,以浸渍法生物测定了该菌株对草地贪夜蛾幼虫和蛹的致病力,并进行了田间应用效果评价。结果表明,分离的Mr006菌株鉴定为莱氏绿僵菌;该菌株对草地贪夜蛾幼虫、蛹均有致病力,用孢子浓度为1×10^(7)孢子/mL接种后,1~5龄幼虫的校正死亡率分别为91.16%、88.38%、70.71%、53.03%和22.73%,蛹的校正死亡率为76.26%;对草地贪夜蛾1~5龄幼虫和蛹的LC50分别为3.55×10^(4)、8.23×10^(4)、3.63×106、4.16×10^(7)、4.23×10^(8)和2.57×10^(5)孢子/mL;用孢子浓度为1×10^(8)孢子/mL接种后,1~5龄幼虫和蛹的LT50值分别缩短至3.47、3.94、4.90、6.73、9.01 d和4.02 d。田间喷施莱氏绿僵菌Mr006分生孢子悬浮液后20 d,对草地贪夜蛾田间防治效果可达64%以上,持效性较好。莱氏绿僵菌Mr006对草地贪夜蛾致病力强,具有较好的生防潜力。

鳄梨采前果实黑褐色病斑病原鉴定及田间药剂防治

为明确位于广东省湛江市的中国热带农业科学院南亚热带作物研究所种质资源圃采前油梨果实表皮黑褐色病斑病原菌,采用组织分离法从病果上分离病原菌,采用形态学结合分子生物学方法鉴定病原菌,选取代表菌株进行油梨果实、叶片、茎干等部位致病性测定,并进行40%多菌灵悬浮液和25%嘧菌酯悬浮液对该病害的田间防治试验。结果表明,从15个油梨病果分离获得病原菌36株,根据形态学观察结合分子鉴定,将36株病原菌划分为刺盘孢属(Colletotrichum)的两个种,对两个种的代表菌株YLQ5-2和FNYG1进行多基因(ITS、GAPDH、CAL、TUB和ACT)系统发育分析,菌株YLQ5-2和菌株FNYG1分别与暹罗刺盘孢(Colletotrichum siamense)和果生刺盘孢(C.fructicola)聚为一支。致病性测定发现,刺伤状态下可引起油梨果实产生黑斑,无伤条件下即可导致油梨叶部发病,刺伤也无法使油梨茎干发病,表现出致病组织特异性。在油梨果实膨大期(7—9月)连续喷施25%嘧菌酯悬浮剂1500倍液和40%多菌灵悬浮剂500倍液3次防治该病害,防效均超过50%以上,其中,25%嘧菌酯的防效较高,达到87.1%。

贝莱斯芽孢杆菌BQ对党参根腐病病原菌抑制效应初探

将贝莱斯芽孢杆菌(Bacillus velezensis)BQ作为最新发现的潜力生防菌。通过平板对峙、孢子萌发、生防机制和离体防治试验检测该菌株对党参根腐病的防治效果。平板对峙试验表明,贝莱斯芽孢杆菌BQ可明显抑制党参根腐病病原菌尖孢镰孢菌DS的生长,菌丝生长抑制率达50.55%,对峙区菌丝发生明显形变;孢子萌发结果表示,贝莱斯芽孢杆菌BQ的代谢产物能有效抑制病原菌DS的孢子萌发;对贝莱斯芽孢杆菌的生防机制进行初探,贝莱斯芽孢杆菌BQ的代谢产物能引起病原菌DS的细胞膜通透性增加,从而导致核酸内容物释放量增加,细胞破裂至死亡。离体防治结果显示,贝莱斯芽孢杆菌BQ对党参根腐病的治疗效果达到46.13%,预防效果达到了63.62%。可见,贝莱斯芽孢杆菌BQ有防治党参根腐病的潜力,可作为生物防治剂进行开发。

10种杀菌剂对德国鸢尾茎腐病菌的室内毒力测定

为筛选适宜的杀菌剂防控德国鸢尾茎腐病,测试亮盾、噁霉灵、瑞至等10种杀菌剂对德国鸢尾茎腐病菌木贼镰刀菌和尖孢镰刀菌的防控效果。结果表明,10种药剂对德国鸢尾茎基腐病病原菌菌丝的生长均有不同程度的抑制作用。其中,抑制效果最好的是解淀粉芽孢杆菌;较好的4种药剂分别为精甲·咯菌腈、噁霉灵、唑醚·甲菌灵、双炔酰菌胺·百菌清,它们对木贼镰刀菌的EC_(50)分别为1.809、61.210、55.570、17.408mg/L,对尖孢镰刀菌的EC_(50)分别为141.9、13.572、39.186、71.251mg/L。

基于伏邪的多囊卵巢综合征代际效应中医理论内涵探讨

多囊卵巢综合征(PCOS)是一种复杂的生殖代谢紊乱性疾病,具有一定的遗传倾向性,其相关症状可在代际间传递。中医所言的伏邪乃藏伏于体内而不立即发病的病邪,其致病模式与PCOS代际效应的病理机制具有相似性。将中医学伏邪理论与现代医学PCOS代际效应机制相结合,可为中医临床早期识别及治疗PCOS提供新思路。

磁弹性生物传感器在食品检测中的研究进展

对引起食品安全问题的主要污染物,如食源性病原体、重金属残留、农药/兽药残留等进行快速而有效的检测是减少食品安全事故发生的重要监控点,高效、灵敏和准确的检测方法对食品检测领域意义重大。近年来,磁弹性生物传感器由于其无毒、低成本、便携、高灵敏度、高准确性和特异性以及可与无线网络连接等特点逐渐成为研究热点。该文主要介绍磁弹性生物传感器的工作原理及其在食品检测应用中的研究进展,以期为食品检测领域提供新思路。

氯化-N-十二烷基吡啶-1-乙酰胺杀灭或抑制病原体的活性研究

季铵盐类表面活性剂是一类低毒、高效的广谱消毒剂,能杀灭多种细菌和病毒,在养殖业和医学等领域的消毒中应用前景广阔。研究旨在明确自主合成的季铵盐类表面活性剂氯化-N-十二烷基吡啶-1-乙酰胺(C12cmpC)对禽源致病菌和牛病毒性腹泻病毒(BVDV)的抗菌抗病毒活性。通过MIC、MBC和时间杀菌试验,明确C12cmpC的体外杀灭、抑制革兰阴性和阳性细菌的效果。通过细胞形态观察、细胞活性检测和BVDV m RNA的qRT-PCR检测,初步明确C12cmpC的抗病毒活性。结果表明,C12cmpC对鹅大肠杆菌(QS195313)的MIC为250 mg·L^(-1),MBC为500 mg·L^(-1)。C12cmpC对大肠杆菌和金黄色葡萄球菌标准株的MIC为31.25 mg·L^(-1),MBC为62.5 mg·L^(-1)。此外,C12cmpC对MDBK细胞的最大安全浓度为5 mg·L^(-1)。其与BVDV作用1、5、30、60 min后,MDBK细胞中病毒m RNA水平均显著降低。研究表明新型季铵盐类表面活性剂氯化-N-十二烷基吡啶-1-乙酰胺具有较好的抗菌抗病毒活性,研究为新型消毒剂的开发提供了理论依据。