Differential Expression Analysis of MUC4 and MUC13 Genes Between Resistant and Sensitive Weaned Meishan Piglets to ETEC F18

MUC4 and MUC13 genes as important candidate genes for enterotoxigenic Escherichia coil (ETEC) F4 resistance,may play an important role in the process of against ETEC F18 infection in weaned piglets. In this study,ETEC F18-resistant and -sensitive weaned Meishan piglets were used,and the expression levels of MUC4 and MUC13 genes in 11 tissues (heart,liver,spleen,lung,kidney,stomach,muscle,thymus,lymph nodes,duodenum and jejunum) were determined by quantitative Real-time PCR. The results showed that MUC4 and MUC13 genes were broadly expressed with different expression levels in all the 11 tissues. In the thymus and lymph tissues,the expression of MUC4 gene in resistant piglets was significantly higher than that in sensitive piglets (P<0.05);In the lung tissue,theMUC13 gene expression level in resistant individuals was significantly higher than that in sensitive individuals (P<0.05),and in the intestinal tissues of duodenum and jejunum, the expression level of MUC13 gene was relatively higher in resistant individuals. Thus we speculated that the high expression of MUC4 gene in immune tissues and MUC13 gene in intestinal tissues might improve the immune ability of piglets,protect and lubricate the intestinal tract, and resist ETEC F18 infection.     

Detection of Serotypes and Virulence Factors of Escherichia coli from Piglets in Beijing

To investigate the cause of piglets diarrhea, and the distribution of the serotype and virulence factors of swine Escherichia coli in Beijing, 400 diarrhea samples were collected. TSA serum agar culture method was used to isolate Escherichia coli, serotype identification test and virulence factor genes test were used to verify the presence of O-antigen. 64 strains of E.coli were isolated from 400 diarrhea samples, among which 42 strains of E.coli were classified as 8 serotypes:O101(18.7%),O64(12.5%),O8(10.9%),O20(10.9%),O45(4.7%),O149(4.7%),O2(1.6%) and O89(1.6%), and the major virulence factors were STa, Stx2e, astA and eaeA. There were 8 mainly serotypes that caused piglets diarrhea in Beijing area, among which O101 serotype accounted for the highest proportion. The major virulence factors were astA and eaeA, accounted for more than 50% of all strains, STa and Stx2e accounted for more than 30% of all strains. These data would provide effective data to support the prevention and control of piglet diarrhea in Beijing.     

犬源大肠杆菌分离株对四环素类药物耐药性的检测

用微量肉汤倍比稀释法测定四环素类等抗菌药物对53株犬源大肠杆菌分离株的最小抑菌浓度(MIC),用PCR和DNA测序方法检测犬源大肠杆菌中四环素耐药基因(tet基因),了解tet基因的流行情况、分析试验菌对四环素类药物的耐药机制。结果表明:25%的分离菌呈多重耐药现象,最多对8种药物耐药。分离菌对四环素类中的土霉素、四环素、多西环素耐药率高,耐药率介于69.8%~86.1%。基因检测结果显示,犬源大肠杆菌中共检测到5种tet基因,分别为tet A、tet B、tet C、tet G、tet L基因,都属于外排泵基因,未检测到核糖体保护基因。其中tet G基因的检出率最高,共检出39株(检出率达70%),有40个菌株同时检出2种或2种以上tet基因,有3株同时检测到4种tet基因,仅有4株未检测到任何tet基因。研究表明:犬源大肠杆菌对常用抗菌药物的耐药情况十分严重,tet基因的携带率高,主动外排是犬源大肠杆菌对四环素类耐药的主要机制。     

Extraction,Purification and Activity Analysis of Lipopolysaccharides from Escherichia coli Isolated from Swine

In order to obtain higher purity and high yield of LPS isolated from Escherichia coli, and evaluate its virulence,excrement of diarrhea piglet was collected as pathological samples, of which, some strains of Escherichia coli were isolated and identified. And furthermore, a strain of Escherichia coli was acquired by 16S rDNA identification. The LPS from this strain of Escherichia coli was isolated with the hot-phenol water method and purified by DNaseⅠ, RNaseA, proteinase K treatment and alcohol precipitation. The polysaccharide, protein and nucleic acid content of purified LPS were detected by phenol-sulfuric acid method, Bradford method and UV points spectrophotometric method. And its bioactivity and acute median lethal dose was determinated by tachypleus amebocyte lysate (TAL) method and acute toxicity experiment method, respectively. The results showed that a strain of highly pathogenic Escherichia coli was successfully isolated. The average yield of purified LPS was 3.74%, the proportion of the polysaccharide was 13.40%, the protein was 0.48%, and the nucleic acid was 0.06%. SDS-PAGE electrophoresis and silver stain showed that the bands were mainly concentrated in the range of 14 to 160 ku. The LAL bioactivity of the prepared LPS was 1.21×10⁷ EU/mg, LD₅₀ of the mouse abdominal cavity was 31.86 mg/kg. The results revealed that the diarrhea piglets in the farm was caused by pathogenic Escherichia coli,purified LPS from this strain of Escherichia coli had the advantages of higher purity, high yield and strong virulence, which would provide theoretical data for clinical prevention and treatment of diarrhea piglets.     

肉鸡舍不同位置和深度垫料细菌浓度不同

为研究鸡舍中不同垫料层中的细菌情况,美国奥本大学的研究人员测定了肉鸡舍垫料不同深度处细菌的浓度。分别对2栋2～5周龄肉鸡舍中比较凉爽处的垫料、鸡舍中间位置的垫料和排风扇附近的垫     

一起非典型鸡新城疫与大肠杆菌病混合感染的诊断与防控

非典型鸡新城疫与大肠杆菌是对养鸡业危害较严重的疾病.介绍了非典型鸡新城疫与大肠杆菌病混合感染的发病情况、临床症状、病理变化、实验室诊断以及防控措施,以供养殖者参考.     

一例蛋雏鸡弱毒禽流感（H9）感染的诊治

1发病情况2010年9月24日,河北省正定县某养殖户购进4000只雏鸡,饲养到25日龄时,鸡群中个别鸡出现甩鼻现象,病初鸡群饮水、吃料正常,4～5天后病鸡增多,有流鼻液现象。用泰乐菌素和磺胺药治疗后症状减轻,但大群鸡     

一例肉鸡支原体病与大肠杆菌病混感的治疗

<正>1发病情况山东省菏泽市曹县养殖户张某饲养肉鸡8000羽,19日龄时突然发病,主诉病鸡精神沉郁,食欲减退,羽毛松乱,面部和眼肿胀、流鼻涕、呼噜,严重的还伴有咳嗽,排白色或黄绿色稀便,每日伤亡20多只,经笔者询问已发病3~4天。曾有诊断为气囊炎,使用了主要成分为氟苯尼考的药物,但仍有鸡只伤亡,病情未得到有效地控制。2病理变化剖检8只病死鸡,病变大致相同。喉头、气管出血、增厚,气管内见腭裂和喉头有干酪样物,鼻腔内有黏液,眼眶     

败血性和肠毒性大肠杆菌引起犊牛腹泻的诊治

1败血性大肠杆菌病 犊牛舍或围产舍因消毒不及时，导致犊牛接触大量的败血性大肠杆菌。犊牛不能获得足量的高质量、高浓度的免疫球蛋白的初乳。环境条件恶劣，饲养密度过大，脐带消毒不严格，不及时，初乳温度不合理导致免疫球蛋白获取不足都可引起发病。