Response of nursery pigs to a synbiotic preparation of starch and an anti-Escherichia coli K88 probiotic

Postweaning diarrhea in pigs is frequently caused by enterotoxigenic Escherichia coli K88 (ETEC). The aim of this study was to test the efficacy of E. coli probiotics (PRO) in young pigs challenged with E. coli K88. We also tested the synbiotic interaction with raw potato starch (RPS), which can be used as a prebiotic. Forty 17-day-old weaned piglets were randomly assigned to four treatments: treatment 1, positive-control diet (C), no probiotics or RPS but containing in-feed antibiotics; treatment 2, probiotic (PRO), no feed antibiotics plus a 50:50 mixture of probiotic E. coli strains UM-2 and UM-7; treatment 3, 14% RPS, no antibiotics (RPS); treatment 4, 14% RPS plus a 50:50 mixture of probiotic E. coli strains UM-2 and UM-7, no antibiotics (PRO-RPS). The pigs were challenged with pathogenic E. coli K88 strains on day 7 of the experiment (24-day-old pigs) and euthanized on day 10 of the experiment (35-day-old pigs). Probiotic and pathogenic E. coli strains were enumerated by selective enrichment on antibiotics, and microbial community analysis was conducted using terminal restriction length polymorphism analysis (T-RFLP) of 16S rRNA genes. The combination of raw potato starch and the probiotic had a beneficial effect on piglet growth performance and resulted in a reduction of diarrhea and increased microbial diversity in the gut. We conclude that the use of E. coli probiotic strains against E. coli K88 in the presence of raw potato starch is effective in reducing the negative effects of ETEC in a piglet challenge model.     

Modulatory Effects of Vasoactive Intestinal Peptide on Intestinal Mucosal Immunity and Microbial Community of Weaned Piglets Challenged by an Enterotoxigenic Escherichia coli (K88)

Toll-like receptors (TLRs) recognize microbial pathogens and trigger immune response, but their regulation by neuropeptide-vasoactive intestinal peptide (VIP) in weaned piglets infected by enterotoxigenic Escherichia coli (ETEC) K88 remains unexplored. Therefore, the study was conducted to investigate its role using a model of early weaned piglets infected by ETEC K88. Male Duroc×Landrace×Yorkshire piglets (n = 24) were randomly divided into control, ETEC K88, VIP, and ETEC K88+VIP groups. On the first three days, ETEC K88 and ETEC K88+VIP groups were orally administrated with ETEC K88, other two groups were given sterile medium. Then each piglet from VIP and ETEC K88+VIP group received 10 nmol VIP intraperitoneally (i.p.) once daily, on day four and six. On the seventh day, the piglets were sacrificed. The results indicated that administration of VIP improved the growth performance, reduced diarrhea incidence of ETEC K88 challenged pigs, and mitigated the histopathological changes of intestine. Serum levels of IL-2, IL-6, IL-12p40, IFN-γ and TNF-α in the ETEC K88+ VIP group were significantly reduced compared with those in the ETEC group. VIP significantly increased IL-4, IL-10, TGF-β and S-IgA production compared with the ETEC K88 group. Besides, VIP could inhibit the expression of TLR2, TLR4, MyD88, NF-κB p65 and the phosphorylation of IκB-α, p-ERK, p-JNK, and p-38 induced by ETEC K88. Moreover, VIP could upregulate the expression of occludin in the ileum mucosa compared with the ETEC K88 group. Colon and caecum content bacterial richness and diversity were lower for pigs in the ETEC group than the unchallenged groups. These results demonstrate that VIP is beneficial for the maturation of the intestinal mucosal immune system and elicited local immunomodulatory activities. The TLR2/4-MyD88 mediated NF-κB and MAPK signaling pathway may be critical to the mechanism underlying the modulatory effect of VIP on intestinal mucosal immune function and bacterial community.     

Inhibition of adhesion of enterotoxigenic Escherichia coli K88 by soya bean tempe

AIMS: Tempe is a traditional fungal fermented food made from soaked and cooked soya beans. It has been associated with antidiarrhoeal characteristics. This study investigated potential inhibitory effects of tempe on enterotoxigenic Escherichia coli (ETEC) K88. METHODS AND RESULTS: Soya beans were soaked, cooked and subsequently fermented using several Rhizopus spp. Water-soluble filter-sterile extracts were tested for their ability to inhibit growth of E. coli and several indicator microorganisms and to inhibit adhesion of ETEC K88. Antimicrobial activity was found against Bacillus stearothermophilus only. ETEC K88-induced haemagglutination of hamster red blood cells was strongly inhibited by a number of tempe extracts and hardly by the cooked soya bean extract. Furthermore, several tempe extracts were able to inhibit adhesion of ETEC K88 to piglet small intestinal brush-border membranes. CONCLUSIONS: Tempe appeared to interfere with ETEC K88 adhesion rather than showing growth inhibitory properties. SIGNIFICANCE AND IMPACT OF THE STUDY: The results indicate that tempe could exert an antagonistic effect against ETEC through inhibition of adhesion and might therefore have a protective effect against ETEC K88 infection in pigs. Hence, tempe could have potential to use as a feed supplement in the diet of weaned piglets.     

大肠杆菌F18菌毛及其亚型的PCR鉴定

F18菌毛是产肠毒素大肠杆菌 (ETEC)与产vero细胞毒素大肠杆菌 (VTEC)的重要致病因子 ,可介导细菌对小肠细胞的黏附 ,并具有F18ab和F18ac 2个抗原亚型。根据已发表的F18ab菌毛A亚单位 (FedA ab)的基因 (fedA ab)设计 3条引物 ,建立了 2种聚合酶链式反应 (PCR)扩增方法。通过对F18ab 大肠杆菌、F18ac 大肠杆菌、K88 大肠杆菌、K99 大肠杆菌、987P 大肠杆菌、F4 1 大肠杆菌的试验 ,结果表明所建立的PCR方法可特异性鉴定F18 大肠杆菌并区别其亚型F18ab与F18ac     

Protective immune response of bacterially-derived recombinant FaeG in piglets

FaeG is the key factor in the infection process of K88ad enterotoxigenic Escherichia coli(ETEC) fimbrial adhesin. In an attempt to determine the possibility of expressing recombinant FaeG with immunogenicity for a new safe and high-production vaccine in E. coli, we constructed the recombinant strain, BL21 (DE3+K88), which harbors an expression vector with a DNA fragment of faeG, without a signal peptide. Results of 15% SDS-polyacrylamide slab gel analysis showed that FaeG can be stably over-expressed in BL21 (DE3+K88) as inclusion bodies without FaeE. Immunoglobulin G (IgG) and M (IgM) responses in pregnant pigs, with boost injections of the purified recombinant FaeG, were detected 4 weeks later in the sera and colostrum. An in vitro villius-adhesion assay verified that the elicited antibodies in the sera of vaccinated pigs were capable of preventing the adhesion of K88ad ETEC to porcine intestinal receptors. The protective effect on the mortality rates of suckling piglets born to vaccinated mothers was also observed one week after oral challenge with the virulent ETEC strain, C83907 (K88ad, CT+, ST+). The results of this study proved that the adhesin of proteinaceous bacterial fimbriae or pili could be overexpressed in engineered E. coli strains, with protective immune responses to the pathogen.     

Fimbriae in Escherichia Coli Isolated from the Small Intestine of Piglets

Ninety E. coli strains, isolated from piglets which had died from neonatal diarrhea, were tested for the presence of K88, K99, 987P and type 1 fimbriae. Two or more types of fimbriae were demonstrated in 14 of the strains, a single fimbria! type in 44 strains while in 32 strains no fimbriae were detected. Of the 14 E. coli strains with more than 1 type of fimbriae, 12;, 10, 8 and 4 strains showed K88, K99, 987P and type 1, respectively. Twelve E. coli strains were isolated from piglets which had died in the neonatal period without showing signs of neonatal diarrhea at necropsy. One strain showed 987P and 3 strains showed type 1 fimbriae, while the remaining 8 strains were unfimbriated. Sixteen fimbriated E. coli strains were subcultured in order to examine the stability of fimbrial expression in the strains. The K88 and the type 1 fimbriae were regularly expressed, while the K99 and 987P were inconsistently demonstrated.     

Exopolysaccharides Synthesized by Lactobacillus reuteri Protect against Enterotoxigenic Escherichia coli in Piglets

Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in piglets; ETEC cells colonize the intestinal mucosa with adhesins and deliver toxins that cause fluid loss. This study determined the antiadhesive properties of bacterial exopolysaccharides (reuteran and levan) and related glycans (dextran and inulin) in a small intestinal segment perfusion (SISP) model. The SISP model used 10 jejunal segments from 5-week-old piglets. Five segments were infected with ETEC expressing K88 fimbriae (ETEC K88), while five segments were treated with saline. Every two segments (ETEC and non-ETEC infected) were infused with 65 ml of 10 g liter⁻¹ of glycans or saline (control) for 8 h. High-resolution melting-curve (HRM) quantitative PCR (qPCR) indicated that E. coli is the dominant bacterium in infected segments, while other bacteria were predominant in noninfected segments. Infection by ETEC K88 was also verified by qPCR; gene copy numbers of K88 fimbriae and the heat-labile toxin (LT) in mucosal scrapings and outflow fluid of infected segments were significantly higher than those in noninfected segments. Genes coding for K88 fimbriae and LT were also detected in noninfected segments. LT amplicons from infected and noninfected segments were 99% identical over 481 bp, demonstrating the presence of autochthonous ETEC K88. All glycans reduced fluid loss caused by ETEC K88 infection. Reuteran tended (P = 0.06) to decrease ETEC K88 levels in mucosal scraping sample, as judged by qPCR. Fluorescent in situ hybridization analysis demonstrated that reuteran significantly (P = 0.012) decreased levels of adherent ETEC K88. Overall, reuteran may prevent piglet diarrhea by reducing adhesion of ETEC K88.     

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0149、0107、0139、093和091为主,共133株,占定型菌株的57.1%;拥有est Ⅰ、estⅡ、elt、stx2e和eae A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,0149血清型与est Ⅰ或estⅡ elt密切相关,在F18菌株中,0107血清型与est Ⅰ或estⅡ、0139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0149、0107、093和098等血清型为主,0149:K88菌株主要与estⅡ或estⅡ elt肠毒素相关,0107:F18菌株主要与estⅡ相关,093和098血清型菌株主要与estⅡ肠毒素相关;STEC菌株以0139: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0107:F18和0116:F18血清型为主,主要与est Ⅰ stx2e或estⅡ stx2e密切相关,ETEC/AEEC菌株以091和0107血清型为主,全部拥有肠毒素est Ⅰ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.     

Effects of the antimicrobial peptide cecropin AD on performance and intestinal health in weaned piglets challenged with Escherichia coli

This study was conducted to determine the effects of the antimicrobial peptide cecropin on performance and intestinal health in piglets. Newly weaned barrows were randomly assigned to one of three treatments (n=8), including a corn-soybean basal diet or similar diets supplemented with antibiotics (100 mg/kg kitasamycin plus 800 mg/kg colistin sulfate) or 400 mg/kg cecropin AD. On day 13, all piglets were orally challenged with 10(9)CFU/mL of Escherichia coli K88. On day 19, all piglets were euthanized and sampled. Before challenge, piglets fed antibiotics had greater weight gain, feed efficiency, nitrogen and energy retention than the control (P<0.05). E. coli challenge decreased weight gain, feed intake and feed efficiency for the control piglets (P<0.05) but not for the antibiotic or cecropin AD treated piglets. The incidence of diarrhea post-challenge in the antibiotic and cecropin AD treatments decreased compared with the control piglets. The total viable counts of cecal E. coli were lower while the Lactobacilli counts were higher in the antibiotic and cecropin AD treatments compared with the control (P<0.05). Cecropin AD treatment decreased total aerobes while increasing total anaerobes in the ileum (P<0.05). A higher villus height to crypt depth ratio in the jejunum and ileum as well as a deeper crypt depth in the jejunum and higher villus height in the ileum were observed in piglets fed antibiotics or cecropin AD compared with control piglets (P<0.05). Piglets fed the control diet had lower levels of secretory IgA in their jejunum and lower serum IgA, IgG, interleukin-1β and interleukin-6 compared with the other treatments (P<0.05). Overall, these data suggest that cecropin AD enhances pig performance through increasing immune status and nitrogen and energy retention as well as reducing intestinal pathogens in weaned piglets.     

粘杆菌素对断奶仔猪血液电解质稳态的影响

本试验选用21日龄断奶的三元杂交仔猪40头,按单因子设计分为2组,处理1饲喂添加0．02％粘杆菌素日粮,处理2饲喂基础日粮,试验期28d。观察并记录每天的腹泻情况,计算各周的腹泻指数;并分别于试验的第7、14和28d考察仔猪前腔静脉血中电解质水平的变化以及各肠段大肠埃希氏菌和乳酸杆菌的数量。结果表明粘杆菌素能显著抑制各肠段大肠埃希氏菌的繁殖,防治仔猪腹泻（P〈0．05）,显著提高血清磷、镁和亚铁离子含量（P〈0．05）。结果提示粘杆菌素可增强仔猪抗应激能力,降低腹泻导致的水和电解质损失,维持血液内环境的平衡。     

Appearance of enterotoxigenic Escherichia coli in piglets with diarrhea in connection with feed changes

Twelve weaned piglet (3-week-old) were divided into three groups according to time of feed change and observed for diarrhea during the time they were 3 to 8 weeks of age. A total of 553 strains of Escherichia coli were isolated from rectal fecal samples and examined for heat-labile (LT) and heat-stable (ST) enterotoxins, pilus antigens (K88, K99, and 987P), hemolysin (Hly), raffinose utilization (Raf) and drug resistance. Enterotoxins and/or hemolytic E. coli strains appeared in the rectal feces of 5- to 6-week-old piglets with diarrhea in connection with feed change and changing temperatures. Most of the isolates showed multiple drug resistance to sulfonamides (Sa), streptomycin (Sp), ampicillin, and/or mercury. Enterotoxigenic E. coli isolates represented four phenotypes: K88+.LT+.Hly+.Raf+.(SaSmCpTcKmSp) (12 strains), K99+.ST+.Raf+.(TcKm) (7 strains), ST+.Raf+.(TcKm) (7 strains), and ST.+(SaSmKm) (25 strains). The drug resistance determinants were transferable concurrently and some of them mobilized the determinants for K88, LT, Hly, and Raf to an E. coli C strain.     

刺五加提取物对早期断奶仔猪肠道微生物多态性的影响

选用21日龄断奶的三元杂交仔猪60头,随机分为3个处理,处理1饲喂添加0.1%刺五加提取物日粮,处理2饲喂添加0.02%硫酸粘杆菌素日粮,处理3饲喂基础日粮。分别于添加后第7、14和28 d从各处理随机取5头试猪,处死后无菌采集空肠、回肠和盲肠内容物,采用体外培养计数法和PCR/DGGE技术,测定其中乳酸杆菌和大肠杆菌的数量及细菌菌群的变化。结果表明,第7 d时,提取物组回肠内容物大肠杆菌数量显著低于对照组;各肠段内容物乳酸杆菌数量均显著高于其它2组。第14 d时,提取物组各肠段内容物大肠杆菌数量均显著低于其它2组;空肠和回肠内容物乳酸杆菌数量显著高于其它2组,且盲肠内容物乳酸杆菌数量显著高于对照组。第28 d时,提取物组空肠和回肠内容物大肠杆菌数量显著低于其它2组,盲肠内容物大肠杆菌数量也显著低于对照组;回肠内容物乳酸杆菌数量显著高于其它2组。各时间点提取物组盲肠内容物细菌DGGE条带数较对照组多,第28 d时空肠内容物细菌DGGE条带数比对照组多;3个处理间各肠段内容物DGGE图谱间的相似性均达56.9%以上。提示刺五加提取物有助于提高肠道内容物乳酸杆菌的数量,抑制大肠杆菌增殖,显著增加肠道微生物的多样性,这可能是其防治断奶仔猪腹泻、促进生长的机理之一。     

Response of piglets weaned from sows fed diets supplemented with conjugated linoleic acid (CLA) to an Escherichia coli K88+ oral challenge

Seventy-eight Cotswold piglets weaned from sows receiving 0% or 2% conjugated linoleic acid (CLA)-supplemented rations from day 85 of gestation through lactation were allocated to nursery diets (ND) according to their dam's lactation ration (LR) as follows (1) 0%-0% (0% CLA LR: 0% CLA ND, n = 17); (2) 0%-2% (0% CLA LR: 2% CLA ND, n = 17); (3) 2%-0% (2% CLA LR: 0% CLA ND, n = 23); and (4) 2%-2% (2% CLA LR: 2% CLA ND, n = 21). At 28 ± 2 days of age all piglets received an oral Escherichia coli K88+ (enterotoxigenic Escherichia coli, ETEC) challenge and were subsequently monitored for scour development and overall health until 36 ± 2 days of age, after which blood and tissue samples were collected. Piglet BW was not affected by dietary CLA supplementation to LR (P > 0.05). However, by day 36 piglets receiving 2% CLA-supplemented ND were significantly lighter (P < 0.05) than piglets receiving control diets. Average daily gain and feed efficiency were not affected by CLA supplementation. Average daily feed intake (ADFI) was greater for piglets weaned from 2% CLA-supplemented sows from day 17 to 28 (P < 0.05), otherwise ADFI was unaffected by dietary CLA supplementation (P > 0.05). The development of scours was less severe in piglets weaned from 2% CLA-supplemented sows at 8, 24, 48 and 56 h after ETEC challenge (P < 0.05). Intestinal coliform and lactic acid bacteria populations post challenge were not affected by CLA supplementation. However, cecal ammonia-N was numerically greatest in 0%-0% piglets compared to the other treatment groups, and the total volatile fatty acid production was numerically lower in 0%-0% and 0%-2% piglets compared to 2%-0% and 2%-2% piglets. In addition, piglets weaned from 2% CLA-supplemented sows had increased serum immunoglobulin A (P < 0.001) and G (P < 0.05) levels and reduced (P < 0.05) intestinal mucosal inflammation compared to piglets weaned from control sows. Although there were no obvious additional health effects observed when CLA was provided in ND, supplementing sow rations with 2% CLA from mid-gestation through weaning appears to have immune-stimulating carry-over effects post weaning. Thus, supplementing sow rations with CLA may be a practical strategy for enhancing passive immune transfer and improving the immune status and overall gut health of nursery piglets.     

Diarrhea in neonatal piglets caused by K99+ST+ enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli strains were isolated from the feces of 34.4% of 64 diarrheaic neonatal piglets on seven farms. Of a total of 518 isolates, 86 (16.6%) were enterotoxigenic and grouped into four phenotypes: K99+ST+ (K99 pilus antigen and heat-stable enterotoxin producing, 36 strains), ST+ (37 strains), K88+LT+ (K88 pilus antigen and heat-labile enterotoxin producing, 11 strains), and K88+ST+ (2 strains). K99+ST+ and ST+ isolates showed multiple drug resistance and most of those (58.3% and 56.8%, respectively) belonged to O serogroup 101. A K99+ST+ isolate proved to be capable of inducing diarrhea and death in hysterectomy-produced colostrum-deprived piglets when orally inoculated.     

Passive immunization of piglets against enterotoxigenic colibacillosis by vaccinating dams with K88ac pili bearing bacterins

Day-old-piglets were passively immunized by vaccinating the pregnant sows with K88ac enterotoxigenic Escherichia coli (ETEC) vaccine. High level of ETEC specific antibodies was excreted in colostrum (3733.33 +/- 1152.13) and maintained a detectable level (100.00 +/- 0.00) up to 21 day post partum (DPP). The IgG was the predominant immunoglobulin followed by IgA and IgM. Piglets born of vaccinated dam (group A) and unvaccinated dam (group B) were challenged in 7 day of age. Clinical and faecal scores were significantly (P < 0.01) low in group A than that of group B. Piglets of group A developed mild diarrhoea (33.33%), while all the control piglets developed profuse diarrhoea and 3 of these died before 14 day of challenge infection.     

Oral immunization of mice with plant-derived fimbrial adhesin FaeG induces systemic and mucosal K88ad enterotoxigenic Escherichia coli-specific immune responses

The importance of adhesins in pathogenicity has resulted in them being useful targets in the defense against bacterial infections. To produce edible vaccines against piglet diarrhea caused by enterotoxigenic Escherichia coli (ETEC), plants were genetically engineered to produce recombinant fimbrial adhesin FaeG. To evaluate the efficacy of the edible vaccine FaeG in mice, the soluble protein extracts were examined by about 15 microg recombinant FaeG for each oral immunization dose per mouse. After four doses of vaccination, both IgG and IgA antibodies specific to K88ad fimbriae were elicited in serum, and specific IgA antibodies were also evoked in feces of the immunized mice. Moreover, visible K88ad ETEC agglutination by the specific serum from the immunized mice was observed, implying the antibody was highly specific and effective. Results from an in vitro villous-adhesion assay further confirmed that serum antibodies of the immunized mice could inhibit K88ad ETEC from adhering to pig intestinal receptors, further demonstrating the oral immune efficacy of the plant-derived FaeG. This study provides a promising, noninvasive method for vaccinating swine by feeding supplements of transgenic plant. Moreover, the low cost and ease of delivery of this edible ETEC vaccine will facilitate its application in economically disadvantaged regions.     

刺五加提取物对早期断奶仔猪生长性能和血清生化参数的影响

早期断奶会使仔猪产生心理、环境和营养应激反应,引起仔猪腹泻、营养不良和生长迟滞等。本试验通过在日粮中添加刺五加提取物,饲喂21日龄断奶仔猪,观察其生长性能、腹泻指数、器官指数和血清生化参数等指标的变化,为开发绿色防病促生长剂提供理论依据。结果表明,刺五加提取物能够显著提高早期断奶仔猪的平均日采食量和平均日增重(P<0.05),降低料肉比,显著防治早期断奶仔猪腹泻(P<0.05),其作用强于粘杆菌素;刺五加提取物组第1周的α-淀粉酶、谷草转氨酶和谷丙转氨酶活性均大于对照组(P>0.05),第2周的尿素氮含量极显著大于抗生素组和对照组(P<0.01),碱性磷酸酶活性显著小于对照组(P<0.05),第4周的α-淀粉酶和脂肪酶活性显著大于对照组(P<0.05)。上述结果提示,刺五加提取物能够缓解仔猪的早期断奶应激,增强机体抵抗力,促进生长。     

A probable new adhesive factor (F42) produced by enterotoxigenic Escherichia coli isolated from pigs

Three enterotoxigenic Escherichia coli (ETEC) strains (coded 62, 104, and 567/7) isolated from piglets with neonatal diarrhea produced only a thermostable enterotoxin. Although these strains showed mannose-resistant microhemagglutination (MRMH), the responsible factor was serologically different from the known hemagglutinating colonization factors from porcine strains (K88, K99, and F41). Bacterial cells from these strains adhered to HeLa cells and pig brush borders. Electron microscope studies revealed the presence of fimbria-like structures on bacterial cells grown at 37 C but not on cells grown at 18 C. The antiserum prepared from partially purified fimbrial antigen (provisionally called F42) inhibited chicken erythrocyte MRMH caused by these strains as well as adherence of strain 567/7 to HeLa cells and to pig brush borders. These data taken together suggest the existence of a new hemagglutinating adhesin that is different from those so far described for porcine ETEC.     

Intestinal receptors for adhesive fimbriae of enterotoxigenic Escherichia coli (ETEC) K88 in swine – a review

Determining the structure of the intestinal receptor for enterotoxigenic Escherichia coli (ETEC) K88 fimbriae will make it possible to develop new strategies to prevent K88+ ETEC-induced disease in pigs. Putative K88 adhesin receptors have been identified in both intestinal brush border and mucus preparations as either glycoproteins or glycolipids. Proteins with sizes of 25, 35, 40–42, 60, and 80 kDa in the intestinal mucus and 16, 23, 35, 40–70, 74, 210, and 240 kDa in brush border membranes were reported to bind specifically to K88ab and K88ac fimbriae. The factors accounting for these variable results may include the variants of K88, ages, breeds, and phenotypes of pigs, and even the sampling sites in the small intestine. Of the reported K88 receptors, only three brush border receptors, i.e., a pair of mucin-type sialoglycoproteins (210 kDa or 240 kDa), an intestinal neutral glycosphingolipid (IGLad), and a 74-kDa transferrin glycoprotein (GP74), have fulfilled the criteria as phenotype-specific K88 fimbrial receptors. Inhibiting the attachment of ETEC to intestine by modifying the receptor attachment sites has been the key for developing novel approaches to preventing ETEC-induced diarrhea in pigs. These include: (1) receptor analogs from a variety of biological sources, (2) an enteric protected protease, (3) chicken egg-yolk containing anti-K88 fimbrial antibodies, and (4) some Lactobacillus isolates producing proteinaceous components or carbohydrates interacting with mucus components. Future studies should be directed to further characterize the carbohydrate and protein moieties of receptors recognized by the K88 adhesin variants and to identify the genes responsible for susceptibility to K88+ infections. Received: 29 February 2000 / Received revision: 4 May 2000 / Accepted: 5 May 2000     

Acid-Base and Electrolyte Changes in 1–3 Days Old Piglets Infected with Enteropathogenic Escherichia Coli and in Spontaneous Cases of Piglet Diarrhoea

Infection perorally with enteropathogenic E. coli (ST +LT) bacteria in 57 newborn piglets gave rise to watery diarrhoea in 50 (88%) piglets and was lethal in 17 (34 %) cases. The diarrhoea was associated with a progressing partially compensated metabolic acidosis indicated by significantly decreased pH, pCO2 and RE values. The acidosis (BE-values) was significantly correlated with increased blood LA and serum K+ values. The dehydration during the disease was confirmed by increased Hb, Hct, serum protein and urea values as well as loss of weight. The changes were most pronounced in piglets that died and a BE value of —10 mmol/1 seemed to be a critical limit at which the prognosis could be considered poor. The changes in acid-base status and water balance was confirmed in 64 piglets with spontaneous cases of E. coli diarrhoea.