Postovulatory Effect of Intravenous Administration of Lipopolysaccharide (E. coli,O55:B5) on the Contractile Activity of the Oviduct,Ova Transport,Binding of Accessory Spermatozoa to the Zona Pellucida and Embryo Development in Sows

The effect of lipopolysaccharide (LPS) (E. coli, O55:B5), administered 18 h after ovulation in the second oestrus after weaning, on the contractile activity of the oviduct, ova transport, sperm binding to zona pellucida (ZP) and embryo development, was studied in 14 Swedish crossbred (Landrace Yorkshire) multiparous sows. The endotoxin group (E‐group) sows were administered with 300 ng/kg of LPS while the control group (C‐group) sows were administered with 5 ml of saline i.v. via an indwelling jugular cannula. Immediately after evidence of standing oestrus, a Millar^® pressure transducer was placed intraluminally about 3 cm into the mid‐isthmus, via laparotomy. Pressure recordings of the oviduct were collected from all conscious sows until slaughter. After slaughter, the genital tract opposite to the side with the transducer was retrieved, and three equal isthmic segments and the first third of the uterine horn part adjacent to the utero‐tubal‐junction (UTJ) were flushed separately to recover the ova. The intervals (mean±SD) from ovulation to slaughter (OS) and insemination to ovulation (IO) were not different between the E‐group (44.5±5.7 h; 13.3±6.5 h) and the C‐group (42.7±5.9 h; 14.8±4.1 h), respectively. Ova recovery rate (RR) in the E‐group (80.2±22.9%) did not differ from that in the C‐group (85.2±4.5%). The frequency distribution of ova recovered in the different segments did not significantly (p>0.05) differ between the groups. The E‐group showed higher cleavage rate than controls. A higher proportion of spermatozoa bound to the ZP was also found in the E‐group compared with controls. The isthmic intraluminal pressure slightly increased (p=0.07) 18 h after ovulation and immediately following LPS in the E‐group, compared with the C‐group. The frequencies of phasic pressure fluctuations were significantly (p<0.05) lower at 30 and 38 h after ovulation in the E‐ than in the C‐group. It can be concluded from the present study that a single i.v. administration of LPS (300 ng/kg body weight) to sows, 18 h after ovulation might be associated with changes in isthmic pressure and the frequency of phasic pressure fluctuations, increased numbers of spermatozoa attached to the ZP and an enhanced embryo development but not with ova transport rates.     

Antimicrobial,immunological and biochemical effects of florfenicol and garlic (Allium sativum) on rabbits infected with Escherichia coli serotype O55: H7

Veterinary Research Communications - Florfenicol (FFC) is a synthetic broad-spectrum antibiotic and garlic has a bactericidal action against coliforms. This study was carried out to compare the...     

大肠杆菌O111:B4内毒素对大鼠肝脏Fas蛋白表达的影响

为探讨大肠杆菌O111:B4内毒素(ET)对大鼠肝脏Fas蛋白表达的影响,本研究将48只SD大鼠随机分为试验组和对照组,试验组尾静脉注射ET,对照组尾静脉注射等体积无热源生理盐水;两组大鼠分别于注射后3h、4h、8h、12 h各迫杀6只,采集肝脏分别用于Fas蛋白表达的western blot检测和流式细胞术(FCM)检测.结果显示,试验组大鼠Fas蛋白的表达明显高于对照组(p＜0.01),并且呈上升趋势.该结果表明,ET能够有效上调大鼠肝细胞Fas蛋白的表达.     

大肠埃希菌O111∶B4内毒素对大鼠肝脏表达HSP70的影响

应用免疫组织化学技术研究了HSP70在内毒素损伤大鼠肝脏中表达的影响。将48只SD大鼠随机分为对照组(Ⅰ组)和内毒素(ET)组(Ⅱ组),每组各24只。两组大鼠分别经尾静脉注射等量无热源生理盐水和内毒素5 mg/kg体重后,分别在3、4、8、12 h采集肝脏作为检测样本,应用HE染色和免疫组织化学染色技术进行检测。结果表明,肝脏的病理变化在内毒素攻击3 h后明显增多,4 h达到峰值,而在8 h后逐渐下降;在对照组和ET组中均有HSP70表达,但ET组的表达极显著明显高于对照组(P0.01),且ET组HSP70表达量随时间的延长而下降。说明在体内内毒素可诱导HSP70在肝脏中的表达。     

Absorption of horseradish peroxidase by neonatal pig intestinal epithelium: effect of Escherichia coli (055B5) on absorption.

The pathway of macromolecular transport through the neonatal pig small intestinal epithelium was examined, utilizing the cytochemical marker horseradish peroxidase (HRP). The marker was found adsorbed to the apical microvillous of the enterocytes, within apical tubules, and cytoplasmic vacuoles. Extracellular absorbed marker assumed a spherical appearance within the subepithelial spaces but was dispersed within the capillary lumens. Uptake of HRP into the enterocyte occurred in 48-hour old neonatal pigs, but transport into the circulation was not observed. Adherence of Escherichia coli to the surface of the ileal enterocyte did not totally inhibit HRP uptake. The E coli adhered to the surface of the enterocyte or within intercellular vacuoles appeared to be static in as much as they were not involved in the transepithelial migration of envacuolated HRP.     

Relationship between serologic recognition of Escherichia coli 0111:B4 (J5) and clinical coliform mastitis in cattle

Serum IgG1 ELISA titers recognizing gram-negative core antigens (Escherichia coli [J5]) were studied at a large dairy in central California. Population mean log10 titer was 2.7357 (equivalent to 1:544) with a SE of 0.03843. Titers increased with increased lactation number (unstandardized regression coefficient = 0.06733). Changes in lactation number accounted for only 6.77% of titer variation. Titers less than 1:240 were associated with 5.33 times the risk of clinical coliform mastitis. Also, older cattle were at greater risk to develop clinical coliform mastitis. These factors apparently affect incidence in a nonlinear fashion, with greatly increased risk associated with titers less than 1:240 and with fourth or greater lactations.     

Effect of vaccination with the R mutant Escherichia coli (J5) antigen on morbidity and mortality of dairy calves

A prospective cohort study was undertaken to determine the efficacy of Escherichia coli 0111:B4 (J5) vaccination in dairy calves. Calves on 2 units were vaccinated when they were 2 to 3 days old and 2 weeks later with the J5 antigen or they were left unvaccinated, and were observed during the first 60 days of age for morbidity and mortality. Events recorded were death, the first case of illness, the first sign of a respiratory tract condition, the first sign of diarrhea, and the first treatment. The time to death or to a morbid event was examined as a function of vaccination status, using the Cox model of survival analysis, where serum IgG concentration at 2 to 3 days of age and gender of the calf were included to control confounding. Signs of morbidity in 517 calves were followed, 189 from unit 1 and 328 from unit 2. Vaccination was associated with a 2.15-fold reduction in risk of death on unit 2 (P = 0.042), but with a 2.43-fold increase in risk of death on unit 1 (P = 0.0035). The only association found between vaccination and morbidity was a 1.34-fold reduction in risk of respiratory tract signs for vaccinated calves on unit 2 (P = 0.055). Necropsy results and clinical investigations indicated that calves on unit 1 were poorly nourished and emaciated. Antibodies to J5 2 weeks after vaccination were significantly (P = 0.0002) lower in calves on unit 1 than in calves on unit 2. The findings offered a possible explanation for the adverse vaccination effect in calves on unit 1.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of passive transfer status and vaccination with Escherichia coli (J5) on mortality in comingled dairy calves

The effect of vaccination with a commercially available R-mutant coliform mastitis vaccine on the survival of comingled dairy calves on a farm with endemic salmonellosis was examined. A total of 864 calves were randomly assigned to either vaccine (n = 435) or control (n = 429) groups. Passive transfer status of each calf was determined using refractometer determination of serum total protein concentration. Logistic models were developed to determine the effects of vaccine group and passive transfer status on calf survival to 100 days of age. In a model in which serum protein concentration was treated as a categorical variable, increasing serum total protein concentrations were associated with decreased mortality until these concentrations exceeded 6.0 g/dL. Calves with serum protein concentrations > 6.0 g/dL had increased risk for mortality compared with calves with serum protein concentrations > 5.5 g/dL but < or = 6.0 g/dL. This increased risk for mortality was supported by the results of a logistic model in which serum protein concentration was treated as a continuous variable. The increased risks associated with high serum protein concentration probably reflect the effect of dehydration in calves with occult disease. Neither model demonstrated any significant association between vaccination status and survival to 100 days of age. Based on these results, the routine immunization of calves cannot be recommended as a strategy to prevent mortality on farms with endemic salmonellosis.     

Adhesive fimbriae produced in vivo by Escherichia coli O139:K12(B):H1 associated with enterotoxaemia in pigs

Two strains of E. coli O139:K12 (B):H1 were compared in vitro and in the intestinal environment. Both strains colonized the small intestines of experimentally inoculated pigs and exhibited in vivo a similar relationship to the microvillus border as enterotoxigenic E. coli (ETEC). Strain 107/86 grown on blood agar expressed numerous long flexible non-haemagglutinating fimbriae which were antigenically distinct from the known fimbriae of porcine ETEC. It adhered in vitro to porcine enterocyte brush border fragments. Strain 124/76 grown on blood agar was devoid of fimbriae and did not adhere to brush border fragments. However, fimbriae morphologically and antigenically indistinguishable from those of strain 107/86 were detected in the intestinal environment by direct immunofluorescence and by immuno electron microscopy.     

Immunogenicity of an Escherichia coli (serotype O1) pili vaccine in chickens

Immunogenicity of an oil-emulsified Escherichia coli (serotype O1) pili vaccine was evaluated in chickens. Chickens were vaccinated with 116 micrograms or 29 micrograms of pili protein and challenged with the homologous E. coli via the posterior thoracic air sac. Unvaccinated chickens were challenged to serve as positive controls or left unchallenged to serve as negative controls. Vaccinated chickens were protected against challenge because they suffered low or no mortality; had mild gross lesions in air sacs, pericardial sacs, and livers, and the scored values were significantly (P less than or equal to 0.05) lower than those in the positive controls; and eliminated E. coli from tissues more efficiently than the positive controls.     

A systemic vaccine based on Escherichia coli O157:H7 bacterial ghosts (BGs) reduces the excretion of E. coli O157:H7 in calves

Cattle are the main reservoir of enterohemorrhagic Escherichia coli O157:H7, a bacterium that, in humans, causes hemorrhagic colitis and hemolytic uremic syndrome (HUS), a life-threatening disease, especially in children and older people. Therefore, the development of vaccines preventing colonization of cattle by E. coli O157:H7 could be a main tool for an HUS control program. In the present study, we evaluated bacterial ghosts (BGs) of E. coli O157:H7 as an experimental vaccine against this pathogen. BGs are empty envelopes of Gram-negative bacteria, which retain the morphological surface make-up of their living counterparts and are produced by controlled expression of the cloned protein E, which causes loss of all the cytoplasm content. In this work, E. coli O157:H7 BGs were used for subcutaneous immunization of calves. The vaccinated animals elicited significant levels of BG-specific IgG but not IgA antibodies in serum. Low levels of IgA and IgG antibodies against BGs were detected in saliva from vaccinated animals. Following oral challenge with E. coli O157:H7, a significant reduction in both the duration and total bacterial shedding was observed in vaccinated calves compared to the nonimmunized group. We demonstrated that systemic vaccination with E. coli O157 BGs provides protection in a bovine experimental model. Further research is needed to reach a higher mucosal immune response leading to an optimal vaccine.     

Effect of Bacteriophage in Enterotoxigenic Escherichia coli (ETEC) Infected Pigs

We evaluated effect of enterotoxigenic Escherichia coli (ETEC) specific lytic phage CJ12 in ETEC infected pigs. Phage was mixed with feed at a ratio of 1:1,000 (0.1%). One week after initially providing phage mixed feed, pigs were challenged orally with 10(11) CFU of ETEC and body weight, diarrhea score, bacterial CFU and phage PFU in the feces were measured. Pigs of phage treated groups C (10(6) PFU/g) and D (10(8) PFU/g) showed more resistance to diarrhea due to ETEC infection compared to positive control group B on the third day after the initial challenge. Moreover, during the quantitation of ETEC in feces, both groups C and D showed approximately 63.92 and 60.73% reduced ETEC compared to positive control group B. Phages were successfully isolated from feces in both groups C and D during the experiment without any adverse effects, suggesting the possibility of using CJ12 as a feed additive.     

Sows Intramammarily Inoculated with Escherichia coli: Influence of Time of Infection,Hormone Concentrations and Leucocyte Numbers on Development of Disease

The aim of this study was to identify factors that influence the development of disease in sows inoculated with Escherichia coli in the mammary gland. Ten cross‐bred primiparous sows were intramammarily inoculated with living E. coli bacteria at different time points before parturition: seven sows within 48 h before parturition and three sows approximately 96 h before parturition. Before and after inoculation, blood samples and mammary gland biopsy specimens were collected and clinical observations were made. All seven sows inoculated close to parturition developed a rectal temperature of >39.5°C during the first 48 h post‐partum and two of them also showed other signs of clinical disease. In the sows inoculated 4 days before parturition, the rectal temperature never exceeded 39.5°C during the first 48 h post‐partum and none of them showed any other sign of clinical disease. There was a tendency (P < 0.1) that histological signs of mastitis were more frequent in the sows inoculated close to parturition. There were no overall differences between the two groups of sows in plasma concentrations of cortisol, oestradiol‐17β and 15‐ketodihydro‐PGF_2α before inoculation. Before inoculation, the number of neutrophils in the blood was overall higher (P < 0.05) in the group of sows that were inoculated close to parturition. In comparison, the number of lymphocytes before inoculation had a tendency (P < 0.1) to be lower in that group. The data suggest that the time of infection of the mammary gland relative to parturition and the number of circulating neutrophils at the time of infection influence the development of clinical coliform mastitis in the sow.     

The Effect of Dose and Route of Administration of R-cloprostenol on the Parturient Response of Sows

The aims of the present study were to further examine the efficacy of different doses and routes of R-cloprostenol administration on the parturition response in sows. Fifty crossbred multiparous sows (Landrace x Yorkshire) with an average parity number of 4.7 +/- 2.4 were allocated to induce farrowing by one of the following treatments: Group I (control, n = 10) injection with normal saline 2 ml administered intramuscularly (i.m.); Group II (n = 10) injection with 75 microg of R-cloprostenol administered i.m. (at 7 AM); Group III (n = 10) injection with 75 microg of R-cloprostenol (at 7 AM) together with 10 IU of oxytocin (24 h after injection of R-cloprostenol) administered i.m.; Group IV (n = 10) injection with 37.5 microg of R-cloprostenol (at 7 AM) administered into perivulva region; Group V (n = 10) injection with 37.5 microg of R-cloprostenol (at 7 AM) administered into perivulva region together with 10 IU of oxytocin (24 h after injection of R-cloprostenol) administered i.m. The following parameters: pre-farrowing maternal behaviour, restless behaviour, R-cloprostenol or oxytocin injection to farrowing interval, expulsion intervals, duration of farrowing, total number of piglets born, litter birthweight, umbilical cord morphology and the degree of meconium staining were record. There were no significant differences among groups for the pre-farrowing maternal behaviours. In all the sows, the restless behaviour was not observed. There were no significant effect of oxytocin administration (10 IU, i.m.) on the percentage of umbilical cord morphology and the degree of meconium staining in different groups. There were no significant effect of route and dose of administration on the number of total piglet born, piglet born alive, stillbirth, mummy and litter birthweight. No significant effects of the different groups were found on the R-cloprostenol and oxytocin injection to farrowing interval, expulsion interval and farrowing duration. In conclusion, the present results demonstrated that a half dose (37.5 microg) of R-cloprostenol administered into the perivulva region was effective for inducing farrowing as the full recommended dose (75 microg) administered into the neck region (i.m.) and with no restless behaviour.     

A preliminary study of Salmonella, verocytotoxigenic Escherichia coli/Escherichia coli O157 and Campylobacter on four mixed farms

The aims of this study were to investigate the incidence of Salmonella, verocytotoxigenic Escherichia coli (VTEC)/Escherichia coli O157 and Campylobacter on four mixed farms and to characterize the isolates in terms of a range of virulence factors. Eighty-nine composite (five different samples from the same animal species combined) faecal [cattle (24), pigs (14), sheep (4), poultry (4), horses (7), deer (4), dogs (9), rodents (2) and wild birds (20)] samples, 16 composite soil samples plus 35 individual water samples were screened using culture-based, immunomagnetic separation and molecular methods. Salmonella was detected in bovine faeces, cattle and poultry house water. Salmonella serotypes/phage types included Dublin, Kiel and Typhimurium DT193, and most isolates were spvC, invA and rck positive. The pefA and rck genes were found exclusively in the non-Typhimurium strains, while Salmonella Dublin and Salmonella Kiel strains carried Salmonella genomic island I marker(s). VTEC/E. coli O157 were found in deer and dog faeces only. The E. coli O157 isolate was an enteroinvasive E. coli, while the VTEC isolate was untypable but carried the vt1, eaeA, hlyA, tir and eptD genes. This article reports the first confirmed carriage of E. coli O157 in Irish deer. Campylobacter species were not detected over the course of this study. It was concluded that [1] Salmonella, VTEC and Campylobacter have low (<5%) prevalence or are absent on the farms in this study; [2] water was an important source of bacterial pathogens; [3] both dogs and deer may act as a source of pathogenic E. coli and [4] key virulence and resistance determinants are widespread in farm Salmonella strains. This study highlights the need to control water as a source of pathogens and suggests that the domestic pets and deer should be considered in any farm risk assessment.