Isolation and Identification of a Pathogenic E.coli Strain Causing Diarrhea in Foxes

[Objectives] The study aimed to identify the pathogenic E. coli strain that caused diarrhea in foxes and to analyze its drug sensitivity.[Methods] A pathogenic E. coli strain was isolated from dead foxes with diarrhea. By conventional bacterial isolation and culture, morphological observation, pathogenicity test and K-B disc method, the isolated strain was identified as pathogenic E. coli .[Results] The isolated pathogen was highly sensitive to ceftriaxone, cefotaxime, ciprofloxacin and lincomycin, moderately sensitive to enrofloxacin, neomycin, gentamycin, spectinomycin, florfenicol, amikacin and polymyxin, and resistant to ampicillin, amoxicillin and doxycycline.[Conclusions] This study provided reference for the prevention and control of diarrheal diseases in foxes in Qinhuangdao region.

Frequency of E.coli pathotypes in acute diarrhea of children and its related factorsat Beassat hospital,Sanandaj

Objective:Diarrhea is a leading cause of morbidity and mortality among children in developing countries.The bacterial pathogen most commonly associated with childhood diarrhea is Escherichia coli.A one-year prospective study was carried out in Sanandaj to determine the prevalence and roles of the different E.coli pathotypes in children less than five years of age with acute diarrhea.Methods:Rectal swab were collected prospectively from children with acute diarrhea and transported to the Department of Microbiology,School of Medicine, KUMS,Sanandaj during 2008.The study was approved by the institutional ethics committee.Results:During this study period,rectal swabs were investigated from a total of 466 children 1 to 144 months of age(mean, 29.97 months±S.D) with diarrhea.Among the children,191(41%,191/466) were girls,and 275 (59%,275/466) were boys.The age-specific incidence rates of acute diarrhea among children 13-24 and 1 - 12 months of age were 37.37%(37/99) and 26.26%(26/99),respectively,during the study period.A total of 99 strains of E.coli were detected.EPEC 59(59.59%) and EIEC 22(22.22%),were the most commonly found Escherichia coli strains detected in stools from children.Disk diffusion testing showed E.coli strains resistance to tetracycline(89.89%),chloramphenicol(88.88%),Ampicillin(79.79%),Amoxicillin (75.75%) and Ceficime(75.75%).Among risk factors like age,sex,haemoglubin,fathers and mothers education,food and weight of children only mother's education was significant(P =0.018).Conclusion: In most of the clinical laboratories in Iran,E.coli does not considered as an etiologic agent responsible for diarrhea. Results in this study revealed that E.coli should be considered as an etiologic agent causing acute diarrhea among children.We therefore,recommend the routine isolation and identification of E.coli strains in all the clinical laboratories in Sanandaj.Guidelines for appropriate use of antibiotics in Sanandaj need updating.

Screening of Traditional Chinese Medicine Prescription for Treating Damp-heat Diarrhea of Piglets

[Objective] The paper was to explore the therapeutic effect of traditional Chinese medicine on damp-heat diarrhea of piglets in summer.[Method] Three prescriptions were developed with a dozen of traditional Chinese medicines,and in vitro antibacterial test against swine standard Escherichia coli [O149：K91,K88 ac（C83907）] was conducted.Moreover,106 natural cases of diarrhea piglets caused by coinfection of damp-heat and E.coli through clinical and laboratory diagnosis were then treated.[Result] The oral liquids prepared by three traditional Chinese medicine prescriptions had certain antibacterial effect on standard pathogenic E.coli.Prescription 2 presented the strongest inhibitory effects on swine E.coli in vitro,with the MIC of 31.25 mg/m L.It had better therapeutic effect,and the effective rate reached 94.74%.[Conclusion] The prescription 2 mainly consisted of Coptis chinensis and Prunus mume might be effective in treatment of piglet diarrhea caused by damp heat and E.coli in clinic.

Effects of Bio-probiotic Betel Bokashi on Raising Pigs and Preventing Diarrhea in Young Piglets in Central Vietnam

Infection of Escherichia coli in piglets is identified as one of major problems in pig husbandry.Data were collected from different experiments conducted at farm levels and results showed that the percentage of piglets infected with E.coli was very high.E.coli infected healthy piglets were up to 48.9%and E.coli infected diarrhea piglets accounted for 88.3%.Using Betel Bokashi and antibiotics in treatment brings about different results.Out of 48 infected piglets,15 piglets were selected for three groups treatment with five each group.Results showed that 92.3%diarrhea piglets treated with Betel Bokashi recovered in 3.85 d,while 100%and 88.23%treated with antibiotics were cured in 4 d and 4.01 d,respectively.Post-treatment piglets in group 3 grew up faster than group 1 and group 2,with gains 231,218 and 212 g,respectively.

Molecular Prevalence and Epidemiological Characteristics of Diarrheagenic <i>E. coli</i>in Children under 5 Years Old in the City of Koula-Moutou, East-Central Gabon

Background and Purpose: Diarrhoeagenic E. coli (DEC) is one of the germs responsible for childhood diarrhea in developing countries. This study aims at determining the prevalence of the five main pathotypes of DEC isolated from faeces of children under five years old with diarrhea or not, living in the city of Koula-Moutou. Methodology: Isolates of E. coli were phenotypically screened on chromIDTM agar and molecularly by multiplex PCR to detect the presence of enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enterohemorragic E. coli (EHEC) and enteroinvasive E. coli (EIEC). The evaluation of their sensitivity to 12 β-lactam antibiotic molecules was carried out by Kirby Bauer method. This method has also made it possible to characterize phenotypically the different β-lactamases produced. Results and Conclusion: Overall, at least one DEC pathovar was detected in the 63 E. coli strains with phenotypic and molecular frequencies of 63.5% and 68.5% respectively. Thus, ETEC (28.3%) and EHEC (28.3%) were the most frequent DEC in diarrheal isolates. ETEC/EHEC hybrid was recorded in both groups with rates of 7.5% in diarrheal cases and 10.0% for controls. The results showed produced carbapenemase type β-lactamases (31.7%), followed by ESBL (24.4%) and few produced high level penicillinases (4.9%). The DEC, in particular ETEC and EHEC are most likely the epidemiological agents responsible for childhood diarrhea in this study.

Characterization of Virulence Factors in Enteroaggregative and Atypical Enteropathogenic Escherichia coli Strains Isolated from Children with Diarrhea

Enteroaggregative (EAEC) and atypical enteropathogenic (EPEC) Escherichia coli are important bacterial etiologic agents causing diarrhea among children. The aim of the present study was to examine the impact of virulence factors predisposes to diarrhea. In this study some virulence properties were examined on 11 EAEC and 8 EPEC strains identified by Polymerase Chain Reaction (PCR), isolated from stool samples of children were analyzed genotypically and phenoltypically for the prevalence of virulence factors. The most frequently detected factor was resistance to serum (94%), followed by curli fimbriae (78%), biofilm production (73%), and gene coding for Extended-Spectrum Beta-Lactamase (ESBL) (68%). EPEC isolates showed at least three of the evaluated properties, while EAEC isolates showed at least two. The prevalence of these virulence factors between the two strains showed no statistical difference. This study showed the heterogeneity of the virulence profile of the isolates of EAEC and atypical EPEC strains and suggests that this diversity may influence in the disease severity.

基于微生物组和宿主转录组整合分析香砂六君子汤对ETEC诱导断奶腹泻仔猪回肠损伤的调控机制

本研究旨在探讨香砂六君子汤对产肠毒素大肠杆菌(entexotoxigenic Escherichia coli,ETEC)诱导的断奶仔猪腹泻的干预作用及其机制。将24头21日龄断奶仔猪随机分为空白组(CON)、模型组(MOD)和香砂六君子汤组(XS),连续14 d给XS组灌服香砂六君子汤(1 mL·kg^(-1),1 g·mL^(-1)),其余组灌服等量无菌水,第15天给MOD组、XS组仔猪按1 mL·kg^(-1)连续3 d灌服1011 CFU·mL^(-1) ETEC菌液,XS组继续灌服香砂六君子汤。分别记录各组仔猪腹泻评分,HE法检测回肠组织病理学变化,实时荧光定量PCR检测回肠组织IL-1β、IL-6、IL-8 mRNA水平,转录组学分析回肠组织RNA差异表达情况,微生物宏基因组学分析回肠菌群变化情况,Western blot检测回肠组织p-p38/p38、p-ERK/ERK、p-JNK/JNK蛋白水平。结果表明,灌服ETEC后,MOD组腹泻评分极显著高于CON组(P<0.01),回肠组织结构破坏,V/C值极显著下降(P<0.01),且IL-1β、IL-6和IL-8 mRNA表达量极显著升高(P<0.01),肠道菌群门水平上变形菌门极显著上调(P<0.01),厚壁菌门极显著下调(P<0.01),属水平上乳酸菌属下调,志贺菌属上调,回肠组织p-p38/p38和p-JNK/JNK比值显著或极显著升高(P<0.05或P<0.01)。与MOD组相比,XS组腹泻评分极显著下降(P<0.01),回肠组织结构完整,V/C值极显著升高(P<0.01),回肠组织IL-1β、IL-6和IL-8 mRNA表达量显著或极显著降低(P<0.05或P<0.01),肠道菌群门水平上变形菌门极显著下调(P<0.01),厚壁菌门极显著上调(P<0.01),属水平上乳酸菌属上调,志贺菌属下调,回肠组织p-p38/p38和p-ERK/ERK比值极显著降低(P<0.01)。肠道组织基因转录组学筛选出与炎症免疫相关的差异显著的10个基因,分别为TNFAIP8L2、TRIM67、CXCL2、EGF、NOX1、CCL28、FABP2、FABP6、IL1RAP和CEBPB。微生物组学筛选出各组可能的标志物种分别为CON组的Lactobacillaceae,MOD组的Shigella,XS组的Deinococcus和Eubacterium。综上所述,香砂六君子汤可有效缓解ETEC诱导的断奶仔猪腹泻,提高肠道菌群中有益菌的丰度,逆转ETEC诱发的菌群结构的改变,并可通过抑制MAPK信号通路的激活,从而缓解ETEC诱导的肠道炎性损伤。

Therapeutic effects of Byrsocarpus coccineus root bark extract on bacterially and chemically induced diarrhea in the Wistar albino rat(Rattus norvegicus domestica)

Background : Diarrhea can be caused by pathogenic microorganisms and chemicals. In view of this, Byrsocarpus coccineus Schum and Thonn(Connaraceae) was used to treat diarrhea induced by castor oil or bacteria in Wistar albino rats. Methods : Qualitative and quantitative analyses of an aqueous root back extract of B. coccineus were made and the acute toxicity, antidiarrhea properties, and in vitro and in vivo antimicrobial activities of the extract were investigated in rats. Results : The phytochemical analysis of the root bark extract revealed the presence of flavonoids, alkaloid, saponins, tannins, and phenols. The quantitative analysis showed that saponins formed 10.6% of the extract, tannins 7.6%, flavonoids 6.2%, phenol 5.8% and alkaloids 4.4%. A dose limit of 5000 mg/kg was safe to use in the rats. At a dose of 100 mg/kg, the extract decreased distance travelled by activated charcoal in the gastrointestinal tract, frequency of defecation, and number of unformed faeces caused by castor oil-induced diarrhea, and led to 74.96% inhibition of the diarrhea effects. Escherichia coli and Salmonella pullorum were susceptible to higher concentrations of the extract with a minimum inhibitory concentration of 0.3125 mg/m L. E. coli-infected rats showed depression, weight loss, anorexia, diarrhea, and weakness, which was ameliorated by the extract on day 2 post treatment. Observed congestion, cellular infiltration and necrosis of the liver, intestine and kidney following infection were improved by the extract. Conclusion : B. coccineus extract can be used in the treatment of anaemia, and castor oil-and E. coli-induced diarrhea in rats.

复方银花口服液防治仔猪细菌性腹泻效果

为评估复方银花口服液对仔猪细菌性腹泻的防治效果,选取新生健康仔猪和哺乳腹泻仔猪,开展复方银花口服液对新生仔猪腹泻的预防效果及其联用四黄止痢颗粒治疗哺乳仔猪腹泻的疗效试验。结果显示:复方银花口服液对新生仔猪腹泻预防保护率为91.1%,较恩诺沙星注射液高30.6%;联用四黄止痢颗粒对哺乳仔猪细菌性腹泻的总有效率为88.2%,较恩诺沙星注射液高35.9%。研究表明:复方银花口服液对新生仔猪腹泻有较好预防效果,与四黄止痢颗粒联用可用于临床耐药细菌性腹泻的治疗。

Combined effects of chitosan and microencapsulated Enterococcus faecalis CG1.0007 probiotic supplementation on performance and diarrhea incidences in enterotoxigenic Escherichia coli K88^+ challenged piglets

The aim of this study was to investigate the combined effects of chitosan oligosaccharide(COS) and a microencapsulated Enterococcus faecalis CG1.0007 probiotic(PRO) on growth performance and diarrhea incidences in enterotoxigenic Escherichia coli(ETEC) K88^+ challenged piglets in a 14-d study. Thirty piglets,7.19 ± 0.52 kg initial BW weaned at 21 ± 1 d.were allotted to 5 treatment groups(n = 6)consisting of a corn-soybean meal diet with no additive(negative control, NC), NC + 0.25% chlortetracycline(positive control, PC), NC + 400 mg/kg COS(COS), NC + 100 mg/kg PRO(PRO) and NC + a combination of COS and PRO(CPRO). Pigs were individually housed in cages, acclimated to treatments for a 7-d period and had ad libitum access to feed and water throughout the study, On d 8, pigs were weighed, blood samples were collected, and then orally challenged with 6 mL(1 ×10^(11) cfu/mL) of freshly grown ETEC inoculum. During post-challenge period, blood was sampled at 24 and 48 h to determine plasma urea nitrogen(PUN), and diarrhea incidences and fecal consistency scores were recorded from d 9 to 12. On d 14, all pigs were weighed and then euthanized to obtain intestinal tissue samples for histomorphometric measurements. Growth performance responses were similar among treatments during the pre-and post-challenge periods. There were no significant differences in PUN content, incidences of diarrhea, and fecal consistency scores among treatments. The intestinal histomorphology results did not differ significantly among treatments except for PC with increased(P = 0.0001) villus:crypt ratio compared with the NC. Under the conditions of the present study, it can be concluded that supplementation of piglet diets with 400 mg/kg COS, 100 mg/kg microencapsulated PRO or their combination did not significantly improve piglet growth performance both during the pre-and post-ETEC K88+ oral inoculation. Also, there were no significant reduction of incidences and severity of diarrhea after challenge compared with the control group.

猪源大肠杆菌(ETEC、STEC、AEEC)毒力基因及其与O抗原型的关系

【目的】揭示从我国部分地区仔猪腹泻或水肿病病猪体内分离到的300个大肠杆菌分离株所属病原型(pathotype)、毒力基因及其与O血清型的关系。【方法】O血清型采用常规的凝集试验进行测定,毒力基因采用PCR方法检测。【结果】通过对这300个分离株的O血清型及其毒素、紧密素和黏附素基因进行鉴定,结果显示除50株未定型、17株自凝外,测定出233个分离株的血清型,这些分离株覆盖了45个血清型,其中以O149、O107、O139、O93和O91为主,共133株,占定型菌株的57.1%;拥有estⅠ、estⅡ、elt、stx2e和eaeA基因的菌株分别为102(34.0%)、190(63.3%)、81(27.0%)、57(19.0%)和54(18.0%)株;分离株中有51株K88基因阳性(其中菌毛表达率为100%),75株F18基因阳性(其中菌毛表达率为50.7%),在K88菌株中,O149血清型与estⅠ或estⅡ+elt密切相关,在F18菌株中,O107血清型与estⅠ或estⅡ、O139血清型与stx2e紧密相关。依其毒力特征可将这些分离株分为以下6种类型:ETEC、STEC、AEEC、ETEC/STEC、AEEC/ETEC和AEEC/ETEC/STEC,分别拥有190、24、36、32、17和1个菌株,占分离株的63.3%、8.0%、12.0%、10.7%、5.7%和0.3%。通过分析这些分离株的O血清型、毒素类型和黏附素型之间的相关性:猪源ETEC以O149、O107、O93和O98等血清型为主,O149:K88菌株主要与estⅡ或estⅡ+elt肠毒素相关,O107:F18菌株主要与estⅡ相关,O93和O98血清型菌株主要与estⅡ肠毒素相关;STEC菌株以O139:F18血清型为主,拥有stx2e;AEEC菌株拥有紧密素,无明显优势血清型;ETEC/STEC菌株以O107:F18和O116:F18血清型为主,主要与estⅠ+stx2e或estⅡ+stx2e密切相关,ETEC/AEEC菌株以O91和O107血清型为主,全部拥有肠毒素estⅠ和紧密素基因。【结论】我国至少存在6种病原型的猪肠道致病性大肠杆菌,其中ETEC为我国部分地区猪大肠杆菌病的主要病原,同时其病原型日益复杂。

舍饲条件下藏仔猪腹泻源大肠杆菌毒力和粘附因子基因检测与耐药性分析

为有效预防和治疗藏仔猪腹泻,采用PCR和Kirby-Bauer纸片扩散法对西藏林芝市舍饲藏仔猪分离的102株腹泻源大肠杆菌(Escherichia coli)毒力基因、粘附因子基因和耐药性进行检测。大肠杆菌毒力基因和菌毛粘附因子基因检测结果表明,检出率最高的菌毛粘附因子基因是F18(45.10%),其次是F4(15.69%),所有菌株均未检出F41基因;102株菌株中有37株菌株未检出菌毛粘附因子基因。毒力基因中检出率最高的是Stx2e基因(25.49%),其次为STb:EAST-1基因(21.57%)和STa:STb基因(17.65%)。大肠杆菌菌毛粘附因子基因和非菌毛粘附因子基因检测结果表明,在检出AIDA-1基因的菌株中菌毛粘附因子基因(F18、F4)的菌株占比为44.73%,在检出paa基因的菌株中菌毛粘附因子基因(F18、F4)的菌株占比为54.17%;在检出eae基因的菌株中没有检测到F4基因。大肠杆菌对氯霉素、四环素、氨苄西林和链霉素表现出高的耐药性,对3种及以上抗生素产生耐药性的大肠杆菌菌株数占总菌株数的86.27%。

维生素E和富铁力对仔猪腹泻疗效的影响

在３７５头１５～２５日龄腹泻仔猪中，研究维生素Ｅ和富铁力处理对仔猪腹泻疗效的影响。试验仔猪分为传统治疗、富铁力加传统治疗以及富铁力和维生素Ｅ加传统治疗三组。结果表明，富铁力和维生素Ｅ加传统治疗组的治愈率达到９４．１７％，极显著地高于传统治疗组（５８．７６％）和富铁力加传统治疗组（７２．５０％）（Ｐ＜０．０１）。同时，用富铁力、富铁力加维生素Ｅ两种方法对１４３头１～２周龄临床健康仔猪进行预防腹泻试验。结果表明，富铁力加维生素Ｅ预防组及富铁力预防组的发病率比原发病率分别降低８４．３和２７．４个百分点。

新疆地区腹泻仔猪源大肠杆菌的分群、血清型鉴定及耐药性分析

旨在了解新疆地区腹泻仔猪源大肠杆菌的系统进化分群、血清型及耐药性。本研究对154份腹泻仔猪粪便样品进行大肠杆菌的分离鉴定,采用多重PCR方法对分离株进行系统进化分群和O血清型鉴定,通过K-B纸片法对其进行药物敏感性检测并通过PCR方法进行耐药基因检测。结果显示:共分离到154株大肠杆菌,包括ETEC(n=24)、STEC(n=21)、EPEC(n=1)、EPEC/STEC(n=2)、ETEC/STEC(n=1)和ETEC/EPEC(n=1),其他104株。系统进化分群显示,多数菌株属于B1(37%)和A群(31%)。定型菌株44株,分别属于10种血清型,以O154、O12、O8、O141和O175为主要流行血清型。151株(98%)为多重耐药菌,对复方新诺明、四环素、氨苄西林、链霉素和氯霉素的耐药率为81%~100%,对阿莫西林/克拉维酸、头孢噻肟、庆大霉素、头孢曲松、环丙沙星和阿米卡星的耐药率为31%~66%,对左氧氟沙星、多黏菌素B、头孢他啶、头孢吡肟、氨苄西林-舒巴坦、哌拉西林-他唑巴坦和亚胺培南的耐药率为1%~19%。耐药基因tetA(88%)、tetG(60%)和cmlA(45%)的携带率较高,而blaCTX-M-1G、aadA1、sul1、aac和blaCTX-M-9G均低于30%,未检测出blaCTX-M-2G、blaTEM、blaSHV和tetE。研究结果表明,新疆腹泻仔猪源大肠杆菌类型复杂,多重耐药形势严峻,耐药基因多样化,且检测出人医临床重要的抗生素耐药表型,应加强对猪场大肠杆菌的耐药性监测。

博落回水提取物对大肠杆菌攻毒断奶仔猪生长性能、腹泻指数和肠道健康的影响

本试验旨在探究饲粮添加博落回水提取物对产肠毒素大肠杆菌(ETEC)攻毒断奶仔猪生长性能、腹泻指数和肠道健康的影响。试验选取30头28日龄健康“杜×长×大”三元杂交断奶仔猪[体重(8.22±0.98)kg],随机分为3个组,每组10个重复,每个重复1头猪。对照组和模型组饲喂基础饲粮,试验组在基础饲粮的基础上添加1 mL/kg的博落回水提取物。预试期3 d,正试期18 d。在正试期第15天,模型组和试验组每只试验猪灌胃10 mL浓度为2×109CFU/mL的ETEC K88菌液,对照组灌胃同一剂量的无菌LB培养液。结果表明:1)第1~14天(攻毒前),与对照组相比,试验组断奶仔猪平均日增重显著提高(P<0.05),料重比显著降低(P<0.05)。第15~18天(攻毒后)和整个试验期(第1~18天),各组断奶仔猪生长性能无显著差异(P>0.05)。2)攻毒后24 h,与对照组相比,模型组断奶仔猪腹泻指数显著提高(P<0.05);与模型组相比,试验组腹泻指数略有降低,但差异不显著(P>0.05)。攻毒后48 h,与对照组相比,模型组断奶仔猪腹泻指数显著提高(P<0.05);与模型组相比,试验组腹泻指数显著降低(P<0.05)。3)与对照组相比,模型组断奶仔猪空肠隐窝深度显著提高(P<0.05),空肠绒隐比显著降低(P<0.05);与模型组相比,试验组断奶仔猪空肠绒隐比、回肠绒毛高度和绒隐比显著提高(P<0.05),空肠隐窝深度显著降低(P<0.05)。4)与对照组相比,模型组断奶仔猪空肠白细胞介素-1β(IL-1β)以及回肠白细胞介素-17(IL-17)、IL-1β、肿瘤坏死因子-α(TNF-α)和白细胞介素-8(IL-8)的mRNA相对表达量显著提高(P<0.05);与模型组相比,试验组断奶仔猪空肠白细胞介素-18(IL-18)、IL-8和IL-1β以及回肠IL-17、IL-1β、TNF-α和IL-8的mRNA相对表达量显著降低(P<0.05)。综上所述,饲粮添加1 mL/kg的博落回水提取物能够改善断奶仔猪生长性能,缓解大肠杆菌感染造成的腹泻、生长性能下降、肠道绒毛高度下降和隐窝深度增加以及肠道炎症等问题。

中草药有效成分酶解法提取工艺优化及其不同配方对引起仔猪腹泻细菌的抑制作用

【目的】探明中草药有效活性成分的提取条件,并筛选抑制仔猪腹泻细菌的高效中药方剂,为生猪养殖过程中绿色防治断奶仔猪腹泻提供理论依据。【方法】采用酶解法提取中草药的有效成分,通过单因素试验研究有效成分提取的温度、时间、pH、酶用量、料液比和处理方式对提取效果的影响,从而确定酶解的最佳条件;利用抑菌圈法测定不同中草药对肠产毒性大肠埃希氏菌、猪霍乱沙门氏菌和绿脓杆菌的抑菌情况,筛选具有较好抑菌效果的中药方剂。【结果】酶解法提取中草药有效成分的最佳工艺为提取温度55℃+提取时间2 h+酶添加量为3%+料液比为1∶25,pH 10,提取前对中草药进行研磨处理。肠产毒性大肠埃希氏菌对单味中草药连翘表现极敏〔抑菌圈直径(Φ)22.2 mm〕,对石榴皮(Φ15.7 mm)和山楂(Φ19.4 mm)表现高敏,优化配方为山楂+虎杖+石榴皮+苦参(Φ18.4 mm);猪霍乱沙门氏菌对单味中草药黄芪(Φ19.2 mm)和川黄柏(Φ15.5 mm)表现高敏,优化配方为黄芪+川黄柏+石榴皮(Φ24.4 mm);绿脓杆菌对单味中草药板蓝根(Φ11.5 mm)和党参(Φ12.1 mm)表现高敏,优化配方为党参+鱼腥草+甘草+龙胆草(Φ15.0 mm)。【结论】中药方剂山楂+虎杖+石榴皮+苦参、黄芪+川黄柏+石榴皮和党参+鱼腥草+甘草+龙胆草分别对引起仔猪腹泻的肠产毒性大肠埃希氏菌、猪霍乱沙门氏菌和绿脓杆菌具有高效抑制作用。

Enterohemorrhagic E.coli effector NleL disrupts host NF-κB signaling by targeting multiple host proteins

Dear Editor,Enterohemorrhagic Escherichia coli(EHEC)0157:H7,a major diarrheagenic pathogen,can cause bloody diarrhea,hemorrhagic colitis,and>90%of hemolytic uremic syndrome in humans(Mead and Griffin,1998).Many previous studies have demonstrated that 0157:H7 could disrupt host ubiquitin(Ub)system by delivering virulence effectors into host cells with the type III secretion system(T3SS).NleL(also named EspX7)emerged as one of such effectors,whose E3-like activity was first identified in vitro in 2011(Lin et al.,2011).

甘草多糖对ETEC诱导断奶腹泻仔猪肠道损伤及肠道菌群的调控机制

将24头21日龄断奶仔猪随机分为空白组(Con)、模型组(Mod)和甘草多糖组(GP),连续14d给GP组灌服甘草多糖水溶液(1mL/kg,10g/L),其余组灌服等量无菌水,第15天给Mod组、GP组仔猪按1mL/kg连续3d灌服1011 CFU/mL的产肠毒素大肠杆菌(enterotoxigenic Escherichia coli,ETEC)菌液,GP组继续灌服甘草多糖水溶液。分别记录各组仔猪腹泻评分、HE法检测肠道组织病理学变化、实时荧光定量PCR检测肠道组织IL-1β、IL-6、IL-8 mRNA水平、微生物宏基因组学分析肠道菌群变化情况、Western blot检测肠道组织NF-κB/MAPK信号通路相关蛋白水平。结果显示,与Con组相比,ETEC感染后Mod组腹泻评分极显著升高(P<0.01),肠道组织结构破坏,大量肠绒毛脱落,V/C值极显著下降(P<0.01),炎性因子IL-1β、IL-6和IL-8mRNA水平极显著升高(P<0.01),变形菌门极显著上调(P<0.01),厚壁菌门极显著下调(P<0.01),乳酸菌属下调,梭菌属上调,肠道组织p-JNK/JNK、p-ERK/ERK、p-p38/p38、p-p65/p65和p-IκBα/IκBα比值极显著升高(P<0.01);与Mod组相比,GP组仔猪腹泻评分极显著降低(P<0.01),肠道结构较完整,仅有少量肠绒毛脱落,V/C值极显著升高(P<0.01),炎性因子IL-6和IL-8 mRNA水平显著或极显著降低(P<0.05或P<0.01),变形菌门极显著下调(P<0.01),厚壁菌门极显著上调(P<0.01),乳酸菌属上调,梭菌属下调,肠道组织p-JNK/JNK、p-ERK/ERK、p-p38/p38、p-p65/p65和p-IκBα/IκBα比值显著或极显著降低(P<0.05或P<0.01)。微生物组学筛选出各组可能的标记物种分别为Con组的Lactobacillus、Mod组的Fusobacterium、GP组的Rothia和Eubacterium。结果表明,甘草多糖可有效缓解ETEC诱导的断奶仔猪腹泻,改善ETEC感染引起的肠道菌群紊乱,提高有益菌丰度,降低有害菌丰度,并通过抑制NF-κB/MAPK信号通路的激活,缓解ETEC诱导的肠道炎性损伤。

华东地区致初生仔猪腹泻大肠杆菌的O血清型和毒力因子

从江苏、江西、安徽等 7个省疑似黄、白痢直肠棉拭及病死猪的十二指肠和肠系膜淋巴结中分离鉴定出 339株病原性大肠杆菌。经O血清型鉴定 ,除 77株未能定型、4 1株自凝外 ,测定出 2 2 1个分离株的O血清型 ,这些分离株覆盖了 6 4个血清型 ,以O1 0 7、O1 0 1 、O2 0 、O93、O1 1 和O1 49为主 ,共 99株 ,占定型菌株的 4 4 80 %。这些血清型与已报道的常见血清型间存在一定差异。运用黏附素单抗对以上菌株进行F4、F5、F6、F1 8、F4 1 5种黏附素检测 ,共 97个分离株表达黏附素 (2 8 6 1 % ) ,而表达两种和 3种黏附素的菌株分别有 2 2株和 8株 ,它们分别占表达黏附素菌株的2 2 6 8%和 8 2 5 % ,其中单独表达F4、F6、F5 +F4 1黏附素菌株分别有 1 8、30、1 5株 ,分别占表达黏附素菌株的1 8 5 6 %、30 93%和 1 5 4 6 % ;同时运用多重PCR对其中 1 4 5个分离株进行毒素基因 (STa、STb、LT、SLT 2e)的检测 ,拥有STa和STb毒素基因的菌株分别占检测菌株的 5 1 72 %和 37 2 4 %。F6、F4、F5 +F4 1和STa。