• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1308-1314
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• 2018

Objective: Gut health improvements were monitored with respect to growth performance, diarrhea incidence, fecal bacterial population and intestinal morphology of suckling pigs orally supplemented with live Lactobacillus salivarius (L. salivarius) oral suspensions and challenged with $F4^+$ enterotoxigenic Escherichia coli (ETEC). Methods: Two groups of newborn pigs from 18 multiparous sows were randomly designated as non-supplemented (control: n = 114 piglets) and L. salivarius supplemented groups (treatment: n = 87 piglets). Treatment pigs were orally administered with 2 mL of $10^9$ colony-forming unit (CFU)/mL L. salivarius on days 1 to 3, then they were orally administered with 5 mL of $10^9CFU/mL$ L. salivarius on days 4 to 10, while those in control group received an equal amount of phosphate buffered saline solution. On day 24 (2 weeks post supplementation), one pig per replicate of both groups was orally administered with $10^8CFU/mL$ $F4^+$ ETEC, then they were euthanized on day 29 of experiment. Results: Results revealed that pigs in treatment group had a statistically significant increase in average daily gain, body weight and weight gain, and tended to lower diarrhea throughout the study. Numbers of Lactobacillus population in feces of treatment pigs were higher than control pigs, especially on day 10 of study. Numbers of total bacteria in intestinal contents of control pigs were also increased, but not Coliform and Lactobacillus populations. Histological examination revealed statistically significant improvements of villous height and villous/crypt ratio of duodenum, proximal jejunum and distal jejunum parts of treatment pigs compared with controls. Duodenal pH of treatment group was significantly decreased. Conclusion: Oral supplementation of live L. salivarius during the first 10 days of suckling pig promoted growth performance and gut health, reduced diarrhea incidence, increased fecal Lactobacillus populations and improved intestinal morphology.

• Journal of Veterinary Science
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• v.23 no.1
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• pp.7.1-7.14
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• 2022

Background: Enterotoxigenic Escherichia coli (ETEC) infection is a primary cause of livestock diarrhea. Therefore, effective vaccines are needed to reduce the incidence of ETEC infection. Objectives: Our study aimed to develop a multivalent ETEC vaccine targeting major virulence factors of ETEC, including enterotoxins and fimbriae. Methods: SLS (STa-LTB-STb) recombinant enterotoxin and fimbriae proteins (F4, F5, F6, F18, and F41) were prepared to develop a multivalent vaccine. A total of 65 mice were immunized subcutaneously by vaccines and phosphate-buffered saline (PBS). The levels of specific immunoglobulin G (IgG) and pro-inflammatory cytokines were determined at 0, 7, 14 and 21 days post-vaccination (dpv). A challenge test with a lethal dose of ETEC was performed, and the survival rate of the mice in each group was recorded. Feces and intestine washes were collected to measure the concentrations of secretory immunoglobulin A (sIgA). Results: Anti-SLS and anti-fimbriae-specific IgG in serums of antigen-vaccinated mice were significantly higher than those of the control group. Immunization with the SLS enterotoxin and multivalent vaccine increased interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) concentrations. Compared to diarrheal symptoms and 100% death of mice in the control group, mice inoculated with the multivalent vaccine showed an 80% survival rate without any symptom of diarrhea, while SLS and fimbriae vaccinated groups showed 60 and 70% survival rates, respectively. Conclusions: Both SLS and fimbriae proteins can serve as vaccine antigens, and the combination of these two antigens can elicit stronger immune responses. The results suggest that the multivalent vaccine can be successfully used for preventing ETEC in important livestock.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.30-30
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• 2003

Escherichia coli strains associated with diarrhea have been divided into the following six major categories on the basis of pathogenic mechanisms: enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC), enteroaggregative E. coli (EAggEC) and diffusely adherent E. coli (DAEC).$\^$15,18/ EPEC, EAggEC, and DAEC strains were classified by their ability to produce distinct patterns of adherence to cultured epithelial cells in virto: localized (LA), aggregative (AA), and diffuse (DA) adherence. The objective of this study was to investigate the relationship of the adherence patterns with AIDA-positive E. coli isolated from diarrheic pigs. (omitted)

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.341-352
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• 2011

Colibacillosis in pigs remain a major swine industry bruden worldwide. Although some progress has been made in treating collibacillosis in pigs by using biosecurity and antimicrobials, it still remain a considerable problem. The use of host-specific bateriophages as a biocontrol is one possible alternative. The purpose of this study was to evaluate the effect of bacteriophage against enterotoxigenic Escherichia coli (ETEC) K88 infection in piglets. Twenty-eight piglets were randomly divided into four groups and each group was allocated with 7 pigs. Group B, C and D were inoculated with 5 ml of ETEC K88 ($1{\times}10^8$ CFU/ml) per head of piglet via oral. Group C and D were fed with bacteriophages (Group C, $1.0{\times}10^6$ PFU/g; Group D, $1.0{\times}10^8$ PFU/g; CJ CheilJedang Corp., Korea) orally as treatment. In piglets administrated bacteriophages and challenged with ETEC K88 (Group C and D), Clinical signs and the growth performance were improved and antibody titers were maintained low level compared with piglets challenged with ETEC K88 (Group B, P<0.05). Group B were shown high pH in the alimentary tracts compared with other piglets (P<0.05). In quantitative analysis by real-time PCR, the results of Group C and D were lower than those Group B in faecal and intestinal samples (P<0.05). Severe villus atrophy and crypt hyperplasia were observed in Group B consequently V/C ratio increased, compared with other piglets. These results indicate that feeding with bacteriophage has effect to prevent ETEC K88 infection in piglets and suggest that use of bacteriophage can be considered a valid antibiotic alternative.

• Korean Journal of Agricultural Science
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• v.41 no.2
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• pp.135-139
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• 2014

Pathogenic E. coli associated post-weaning diarrhea (PWD) and edema disease are common diseases in commercially-housed weanling pigs. An enterotoxigenic E. coli (ETEC) oral challenge model has been used to mimic the physiological responses observed in commercial conditions. However, an oral challenge procedure has two major limitations: (1) the ETEC cell density is unknown at the point of oral inoculation, and (2) blending ETEC with traditional TSB (trypticase soy broth) is not palatable and hence decreases acceptability by piglets. Therefore, the purposes of this study were to (1) establish a regression equation that can be used for estimation of ETEC concentration in dilution media using the spectrophotometric measurement of cell density; and (2) examine survival of ETEC after blending either with TSB, sweetener or dextrose. A strain of ETEC (serogroup beta-hemolytic E. coli O149; K91; F4; toxins LT, STa, STb) was grown in TSB for 3.5 hours, centrifuged, the supernatant was discarded, and the ETEC pellet was then blended either with TSB (100 mL), sweetener (60 mL TSB + 40 mL fruit flavored concentrate), or dextrose (50 mL TSB + 50 mL dextrose; 0.5g/mL dextrose). Cell density was measured using the colorimetric method and also plated on a 5% sheep blood agar for counting of ETEC colony forming units at 0, 5, 35, 65 and 125 min after blending. The optical density at 600 nm explained 83% of ETEC colony forming units, indicating that the established linear equation (y= 6E+08x - 4E+07, P<0.004) can be used for robust quantification of ETEC cell density in TSB, sweetener and dextrose media. When ETEC was blended with sweetener and dextrose, survival of ETEC was decreased by 45% and 72% within 5 min post-blending. Therefore, further research is required to find out the suitable medium that has potential to improve palatability without compromising survival of ETEC.

• Korean Journal of Veterinary Service
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• v.19 no.2
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• pp.139-153
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• 1996

Porcine E coli infection is a disease caused by Enterotoxin produced by Enterotoxigenic Escherichia coli(ETEC). Enteric colibacillosis has become an economically important disease in pigs as a result of increasing intensification of farrowing management. The present study undertaken to obtain the antibiotic sensitivity and distribution of serogroups and pili producibility test of ETEC from E. coli isolates in Chonnam. The results obtained were as follows. 1. A total of 71 isolates identified as E, coli employing IMViC system from rectal specimens of 54 piglets with diarrhea. 2. In antibiotic sensitivity test, isolates showed high sensitivity to AN, CM, Fox, GM, but resistance to EM, NA TC. 3. The distribution of 25 Isolates of serogroups were 0141:K85(11.3%), 08:K87(8.5%), 064:K (5.6%), 0138:K8l (4.2%), 0139 :K82(2.8%), 0157:K88ac(1.4%) and 0149:K9l (1.4%). 4. MRHA of guinea pig erythrocytes was detected in 8 out of 25OK serotypes and 9 out of 46 unidentified serotypes. MRHA titers of serotypes showed from 64 to 128 in 0141: K85, 2 in 0138:K8l and no titers in 0139:K82. 5. The production of heat labile enterotoxin of ETEC was detect 39 out of 52 isolates showed $\beta$-hemolysin, 7 out of 52 isolates showed ${\gamma}$-hemolysin and 6 out of 52 isolates showed ${\gamma}$-hemolysin by $GM_1$ganglioside ELISA. The distribution of LT toxin were in 12 isolate showed $\beta$-hemolysin, 2 isolates showed ${\alpha}$-hemolysin and 3 isolates showed ${\gamma}$-hemolysin in 25 OK serotypes.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.671-677
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• 1996

Erythrocytes from three different animal species were used to determine mannose-sensitive hemagglutination (MSHA) and mannose-resistant hemagglutination (MRHA) of 755 isolates obtained from rectal swabs of healthy pig. In addition, colony hybridization using digoxigenin-dUTP labeled polynucleotide probes was performed for the detection of heat-stable and heat-labile enterotoxin genes carried by MRHA positive isolates. Of 755 strains, 9, 4 and 28 strains gave a positive MRHA with bovine, equine and pig erythrocytes, respectively. Of these isolates, 28 (3.7%) were characterized for positive MRHA by at least one blood. Seven isolates gave a positive MRHA with two kinds of blood. Three gave a positive MRHA with three kinds of blood. Twenty-eight strains, while positive in MRHA, yielded negative signals in the colony hybridization assay for the detection of heat-stable (STaI and STaII) and heat-labile (LT) enterotoxin genes in E. coli.

• Korean Journal of Veterinary Service
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• v.43 no.2
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• pp.53-58
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• 2020

Enterovirulent Escherichia coli are among the most important causes of diarrhea in cattles. Between January and December, 2017, a total of 150 stool specimens from cattles were investigated for enterohaemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), enterotoxigenic E. coli (ETEC) and enteroinvasive E. coli (EIEC) using real-time PCR. 131 E. coli were isolated from feces. The most frequently isolated pathotype in feces was EHEC (37 isolates). EPEC, ETEC and EAEC were detected in feces with 14, 7 and 3 respectively. EIEC was not detected. Antimicrobial resistance test was performed by agar disc diffusion method with 14 antimicrobials. Enterovirulent E. coli isolates showed the highest antimicrobial resistance to ampicillin 61.3%, followed by tetracycline 54.5% and streptomycin 45.5%. They had low resistance to amikacin 11.4%. Of 44 isolates, 37 (84.1%) were resistant to more than 2 antimicrobials. futher study a highest antimicrobial susceptibility to trimethoprim/sulfamethoxazole 50.0% and florofenicol 47.7%.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.9
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• pp.1342-1346
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• 2006

Enterotoxigenic Escherichia coli is a major cause of diarrhea in neonatal and post-weaning piglets. To determine the most common fimbrial antigens of ETEC in piglets with diarrhea, two investigations were carried out on intensive pig farms in Hubei province, central China. In 2002-2003, 227 fecal samples from neonatal and post-weaning piglets with diarrhea were tested for the presence of the fimbrial antigen K88 and K99 of ETEC by the polymerase chain reaction (PCR). Twenty-three (10.1%) of 227 fecal samples were found to contain fimbrial antigen K88, which was identified as K88ac variant; and 13 (5.7%) samples containing K99. In 2004, another 179 fecal samples from diarrheic piglets, 1 day to 6 weeks of age, were tested for prevalence of fimbrial antigen K88, K99 and 987P. Forty-seven (26.3%) of the 179 samples carried at least one of the ETEC fimbrial antigens. K88 antigen was detected in 20.1%. In the 36 samples known to carry fimbrial antigen K88, 32 (88.9%) contained K88ad; and 4 (11.1%) contained K88ac; none of them carried K88ab. Fimbrial antigens K99 and 987P were detected in 1.1% and 6.1%, respectively. Our data indicate that K88 is the most common fimbrial antigen of ETEC associated with diarrhea in piglets in Central China.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.543-552
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• 2020

For efficient prevention and treatment of enteric colibacillosis, understanding about latest virulence factors and antimicrobial resistance of Escherichia coli is essentially needed. The aim of this study was to survey antimicrobial resistance and determine the prevalence of fimbriae and enterotoxin genes among 118 pathogenic E. coli isolates obtained from Korean pigs with diarrhea between 2016 and 2017. The genes for the toxins and adhesins were amplified by polymerase chain reaction (PCR). The susceptibility of the E. coli isolates to antimicrobials were tested using the standard Kirby-Bauer disk diffusion method. The most prevalent fimbrial antigen was F18 (40.7%), followed by F4 (16.9%), and the most prevalent combinations of toxin genes were Stx2e (21.2%), STb:EAST-1 (19.5%), and STa:STb (16.9%), respectively. Among the pathotypes, enterotoxigenic E. coli (ETEC) was the most predominant (67.8%), followed by Shiga-toxin producing E. coli (STEC, 23.7%). We confirmed high resistance rates to chloramphenicol (88.1%), tetracycline (86.4%), streptomycin (86.4%), and ampicillin (86.4%). And the majorities of isolates (90.7%) showed multi-drug resistance which means having resistance to 3 or more subclasses of antimicrobials. Results of this study can be a source of valuable data for investigating the epidemiology of and control measures for enteric colibacillosis in Korean piggeries.