The worldwide use of antimicrobials in different fields has created enormous pressure for the selection of resistance among opportunistic bacterial pathogen. One hundred four E. coli isolates were collected and identified from swine with diarrhea in Korea during the period of 2002. The isolates showed highly resistant to streptomycin (99. 0%), tetracycline (97. 1%), neomycin (91. 3%)and carbenicillin (84. 6%)in antimicrobial susceptibility test. Moreover, all of the isolates showed multiple antimicrobial resistant to more than 3, and 85%of them were resistant to more than 7 of total 14 antimicrobial agents. In comparison with isolates in 1998, resistance to antimicrobials was more frequent among the isolates in 2002. Presence of class 1 integrons was investigated through amplification of the gene with PCR, and could be classified 8 groups by pattern of 4 different amplicons. Class 1 integrons were observed in 67 strains (64. 2%)of E. coli from swine in Korea. One and 1. 6 kbp of amplicons were revealed to contain aadA1 and aadB-aadA1 gene cassettes respectively. Two kbp of amplicon had three different gene cassettes, dhfrXII-orfF-aadA2, and 3. 0 kbp of amplicon includes aadB-cmlA1 gene cassettes.
Animals ; Anti-Bacterial Agents ; Diarrhea/microbiology/veterinary ; Drug Resistance, Multiple, Bacterial/*genetics ; Escherichia coli/*drug effects/genetics ; Escherichia coli Infections/microbiology/*veterinary ; Integrons/*genetics ; Swine ; Swine Diseases/*microbiology

Enterohemorrhagic Escherichia coli serotype O157:H7 is a pathotype of diarrheagenic E. coli that produces one or more Shiga toxins, forms a characteristic histopathology described as attaching and effacing lesions, and possesses the large virulence plasmid pO157. The bacterium is recognized worldwide, especially in developed countries, as an emerging food-borne bacterial pathogen, which causes disease in humans and in some animals. Healthy cattle are the principal and natural reservoir of E. coli O157:H7, and most disease outbreaks are, therefore, due to consumption of fecally contaminated bovine foods or dairy products. In this review, we provide a general overview of E. coli O157:H7 infection, especially focusing on the bacterial characteristics rather than on the host responses during infection.
Animals ; Cattle ; Cattle Diseases/blood/epidemiology ; Developing Countries ; *Enterohemorrhagic Escherichia coli ; Escherichia coli Infections/blood/*epidemiology/veterinary ; *Escherichia coli O157/genetics/pathogenicity ; Feces/microbiology ; Hemolytic-Uremic Syndrome/blood/epidemiology/veterinary ; Operon ; Shiga Toxins/analysis ; Shigella dysenteriae ; Virulence

Iro system and temperature-sensitive hemagglutinin (Tsh) genes were identified by suppression subtractive hybridization (SSH) and selective capture of transcribed sequences (SCOTS). To get more insights in the distribution and the occurrence of the iroC and tsh genes, we examined 243 avian E. coli strains for the presences of the these genes. Among 243 avian E. coli isolates, iroC gene was present in 84.4% strains (205/243). Of the 205 iroC-positive isolates, iroC gene was found in 184 (89.8%), 18(8.8%) and 3 (1.5%) isolates with high, intermediate and low pathogenicity, respectively. Of the 167 tsh-positive isolates, tsh gene was detected in 146 (87.4%), 21 (12.6%) and 0 (0%) isolates with high, intermediate and low pathogenicity, respectively. Among tsh-positive isolates, 89.5 to 100% of the highly pathogenic isolates of O1, O2 or O78 serogroups had the tsh gene, while 53.3% of the highly pathogenic isolates of non-O1, O2 and O78 serogroups had the tsh gene (P<0.01). Suicide vectors for deletion of the iroBCDEN or tsh genes were constructed as follows. The 715-bp fragments of iroB and 603-bp fragment of the iroN were generated by PCR respectively. Both of these two fragments together with EGFP gene were cloned into pUC18, termed pUC18-iroBNEGFP. A resultant suicide vector containing the iroB-EGFP-iroN fragment was obtained and named pMEG375-iroBNEGFP. Similarly, both of the 685-bp fragment of tshF and the 692-bp fragment of the tshR together with gentamycin gene were cloned into pUC18, resulting in pUC18-tshFRGm. A resultant suicide vector containing the tshF-Gm-tshR fragment was named pMEG375-tshFRGm. Mutant derivatives of strain E037 were generated by allelic replacements and were named E037(Deltairo), E037(Deltatsh) and E037(DeltairoDeltatsh). The 50% lethal dose (LD50) of E037, E037(Deltairo), E037(Deltatsh) and E037(DeltairoDeltatsh) in commercial day-old chickens experimentally inoculated via intratrachea were determined to be 10(5.6), 10(8.4), 10(9.0) and 10(9.5)CFU, respectively. In the chicken challenging model, the mutants were tested to determine the individual role of this system for virulence and persistence in chickens. The result suggested that Iro system and Tsh were important in the pathogenicity of APEC.
Adhesins, Escherichia coli ; genetics ; Animals ; Chickens ; Escherichia coli ; genetics ; pathogenicity ; Escherichia coli Infections ; microbiology ; veterinary ; Genes, Bacterial ; genetics ; Mutation ; Nucleic Acid Hybridization ; methods ; Organisms, Genetically Modified ; Poultry Diseases ; microbiology ; Transformation, Genetic ; Virulence Factors ; genetics

Escherichia coli (E. coli) strains were collected from young diarrheic calves in farms and field. Strains that expressed the K99 (F5) antigen were identified by agglutination tests using reference antibodies to K99 antigen and electron microscopy. The K99 antigen from a selected field strain (SAR-14) was heat-extracted and fractionated on a Sepharose CL-4B column. Further purification was carried out by sodium deoxycholate treatment and/or ion-exchange chromatography. Monoclonal antibodies to purified K99 antigen were produced by the hybridoma technique, and a specific clone, NEK99-5.6.12, was selected for propagation in tissue culture. The antibodies, thus obtained, were affinity-purified, characterized and coated onto Giemsastained Cowan-I strain of Staphylococcus aureus (S. aureus). The antibody-coated S. aureus were used in a coagglutination test to detect K99+ E. coli isolated from feces of diarrheic calves. The specificity of the test was validated against reference monoclonal antibodies used in co-agglutination tests, as well as in ELISA. Specificity of the monoclonal antibodies was also tested against various Gram negative bacteria. The developed antibodies specifically detected purified K99 antigen in immunoblots, as well as K99+ E. coli in ELISA and co-agglutination tests. The co-agglutination test was specific and convenient for large-scale screening of K99+ E. coli isolates.
Agglutination Tests/methods/*veterinary ; Animals ; *Animals, Newborn ; Antibodies, Monoclonal/*immunology ; Antigens, Surface/immunology/isolation & purification ; Bacterial Toxins/immunology/isolation & purification ; Cattle ; Cattle Diseases/*immunology/*microbiology ; Chromatography, Gel/veterinary ; Chromatography, Ion Exchange/veterinary ; Chromatography, Liquid/veterinary ; Diarrhea/immunology/*veterinary ; Electrophoresis, Polyacrylamide Gel/veterinary ; Enzyme-Linked Immunosorbent Assay/veterinary ; Escherichia coli/*immunology ; Escherichia coli Infections/immunology/*veterinary ; Immunoblotting/veterinary ; Staphylococcus aureus

Cows infected with Escherichia (E.) coli usually experience severe clinical symptoms, including damage to mammary tissues, reduced milk yield, and altered milk composition. In order to investigate the host response to E. coli infection and discover novel markers for mastitis treatment, mammary tissue samples were collected from healthy cows and bovines with naturally occurring severe E. coli mastitis. Changes of mammary tissue proteins were examined using two-dimensional gel electrophoresis and label-free proteomic approaches. A total of 95 differentially expressed proteins were identified. Of these, 56 proteins were categorized according to molecular function, cellular component, and biological processes. The most frequent biological processes influenced by the proteins were response to stress, transport, and establishment of localization. Furthermore, a network analysis of the proteins with altered expression in mammary tissues demonstrated that these factors are predominantly involved with binding and structural molecule activities. Vimentin and alpha-enolase were central "functional hubs" in the network. Based on results from the present study, disease-induced alterations of protein expression in mammary glands and potential markers for the effective treatment of E. coli mastitis were identified. These data have also helped elucidate defense mechanisms that protect the mammary glands and promote the pathogenesis of E. coli mastitis.
Animals ; Cattle ; Electrophoresis, Gel, Two-Dimensional/veterinary ; Escherichia coli/*physiology ; Escherichia coli Infections/genetics/immunology/microbiology/*veterinary ; Female ; Mammary Glands, Animal/*immunology/pathology ; Mastitis, Bovine/*genetics/immunology/microbiology ; Proteome/*genetics/metabolism ; *Proteomics

In the event of an infectious disease outbreak in cattle, carcasses must be disposed of in a rapid and contained manner. This brief communication details injection of a barbiturate to euthanize cattle inoculated with Escherichia coli O157:H7 followed by carcass composting in a manner that prevents the spread of infectious agents.
Animals ; Cattle ; Cattle Diseases/*microbiology ; Disease Outbreaks/*veterinary ; Escherichia coli Infections/microbiology/*veterinary ; *Escherichia coli O157 ; Euthanasia, Animal/*methods ; Hypnotics and Sedatives/administration & dosage/pharmacology ; Male ; Pentobarbital/administration & dosage/*pharmacology ; Soil

Healthy ruminants carry intestinal Shiga toxin (Stx)-producing Escherichia coli (STEC). Stx has antiviral activities in vitro and STEC numbers correlate with reduced early viremia in sheep experimentally infected with bovine leukemia virus (BLV). This study assessed the impact of intestinal STEC on BLV-induced disease for one year post-BLV-challenge. High STEC scores (CFU/g feces x frequency of STEC-positive samples) correlated with good health, whereas poor weight gain, distress, and tumor development occurred only among animals with low STEC scores. STEC carriage was associated with increased percentages of B cells in peripheral blood.
Animals ; Deltaretrovirus Infections/microbiology/*veterinary ; Intestines/*microbiology ; Leukemia Virus, Bovine/*physiology ; Male ; Sheep ; Sheep Diseases/*microbiology ; Shiga-Toxigenic Escherichia coli/*physiology

Enterotoxigenic Escherichia coli (ETEC) causes neonatal and post-weaning diarrhea in pigs. In order to determine the risk factors, rectal/fecal swabs and visceral organs obtained from pig farms in two regions of South Africa were analyzed microbiologically against risk variables. Seventy-two percent of young pigs were found to be positive for ETEC toxin genes; estB (38.9%), estB/STAP (25%), and estB/LT (13.9%) were dominant. Risk factors for ETEC-diarrhea in pigs include: leaving sick piglets in a pen with healthy piglets [odds ratio (OR) = 33.52; P < 0.0001]; water spillage in pen (OR = 42.87; P < 0.0001); hypothermic piglets (OR = 7.29; P < 0.0001); runt piglets in pen with healthy littermates (OR = 3.65; P < 0.0001); and prolonged use of antibiotics (OR = 3.05; P = 0.05).
Animals ; Animals, Newborn ; Diarrhea ; epidemiology ; microbiology ; Escherichia coli ; genetics ; isolation & purification ; Escherichia coli Infections ; epidemiology ; microbiology ; veterinary ; Genes, Bacterial ; Prevalence ; Rectum ; microbiology ; Risk Factors ; South Africa ; Swine ; Swine Diseases ; epidemiology ; microbiology ; Weaning

The effect of acupuncture in the treatment of young pigs with induced enteropathogenic Escherichia coli diarrhea was histopathologically evaluated by routine hematoxylin and eosin stain. Thirty two pigs weighed 4-5kg and aged 21days old were used in this study. The animals with diarrhea were treated with traditional acupuncture, or enrofloxacin. In the group treated with traditional acupuncture, acupoint GV1 (Jiaochao) was used and in the group treated with antibiotics, enrofloxacin was injected intramuscularly. Ten pigs were inoculated with E. coli, but were not treated and served as nontreated control group. At postinoculation day 6, all pigs of the acupuncture and antibiotic treated groups recovered from diarrhea. In the ascending and descending colons of the nontreated control group, severe infiltration of inflammatory cells in the lamina propria was observed and in the fundic stomach, destruction of the fundic gland architecture and necrotic lesions were observed, however, in the same sites of the acupuncture and antibiotics treated groups, the mucosae of the colon and stomach were relatively similar to those of the normal group. These results indicate that acupuncture treatment is effective in controlling induced E. coli diarrhea in pigs at its early stage.
Acupuncture ; Animals ; Colon/cytology/microbiology/pathology ; Diarrhea/therapy/*veterinary ; Escherichia coli Infections/therapy/*veterinary ; Gastric Mucosa/cytology/microbiology/pathology ; Intestinal Mucosa/cytology/microbiology/pathology ; Male ; Stomach/cytology/microbiology/pathology ; Swine ; Swine Diseases/*microbiology/therapy

A total of 156 Shiga-like toxin producing Escherichia coli (STEC) were isolated from fecal samples of Korean native (100/568, 18%) and Holstein dairy cattle (56/524, 11%) in Korea between September 2010 and July 2011. Fifty-two STEC isolates (33%) harbored both of shiga toxin1 (stx1) and shiga toxin2 (stx2) genes encoding enterohemolysin (EhxA) and autoagglutinating adhesion (Saa) were detected by PCR in 83 (53%) and 65 (42%) isolates, respectively. By serotyping, six STEC from native cattle and four STEC from dairy cattle were identified as O-serotypes (O26, O111, O104, and O157) that can cause human disease. Multilocus sequence typing and pulsed-field gel electrophoresis patterns highlighted the genetic diversity of the STEC strains and difference between strains collected during different years. Antimicrobial susceptibility tests showed that the multidrug resistance rate increased from 12% in 2010 to 42% in 2011. Differences between isolates collected in 2010 and 2011 may have resulted from seasonal variations or large-scale slaughtering in Korea performed to control a foot and mouth disease outbreak that occurred in early 2011. However, continuous epidemiologic studies will be needed to understand mechanisms. More public health efforts are required to minimize STEC infection transmitted via dairy products and the prevalence of these bacteria in dairy cattle.
Animals ; Anti-Bacterial Agents/pharmacology ; Cattle/microbiology ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field/veterinary ; Escherichia coli Infections/epidemiology/microbiology/*veterinary ; Female ; Genes, Bacterial/genetics ; Latex Fixation Tests/veterinary ; Microbial Sensitivity Tests/veterinary ; Multilocus Sequence Typing/veterinary ; Prevalence ; Republic of Korea/epidemiology ; Shiga Toxin 1/genetics ; Shiga Toxin 2/genetics ; *Shiga-Toxigenic Escherichia coli/drug effects/genetics