Enzyme immunoassay for the rapid detection of Escherichia coli O157

An enzyme immunoassay(EIA) to detect Escherichia(E.) coli 0157 in pork was developed by using a sandwich-type assay on the 96-well microplates. All E. coli O157 strains and Citrobacter amalonaticus reacted strongly, however 29 E. coli serotypes and 15 non-E. coli bacterial strains showed negative in E. coli O157 EIA. E. coli 0157 in pork could be detected with in 13 h including 10 h in enrichment broth and 3 h in EIA. As few as 1.8 CFU of E. coli O157 per g of pork could be detected after enrichment, whereas above 1.8 \u3e. 1 o5 CFU of E. coli O157 per g of pork could be detected without enrichment. The E. coli 0157 EIA was a sensitive, easy-to-perform and efficient method for the screening of E. coliO 157 in pork

Seroprevalence and risk factors of Besnoitia besnoiti infection in Korean cattle – short communication

Besnoitia besnoiti is an obligate intracellular parasite that is transmitted by direct contact or via mechanical transmission by flies as vectors. Besnoitiosis causes economic losses in the cattle industry and is regarded as a re-emerging disease in Europe. This study evaluated the seroprevalence of B. besnoiti in Korean cattle using a commercial ELISA kit. Among 558 serum samples, 19 (3.4%) tested seropositive for B. besnoiti. The statistically significant risk factors included age (≥ 2 years), sex (castrated males), and region (lower latitudes) (P < 0.05). The overall seroprevalence suggested a wide distribution of B. besnoiti infection in cattle reared in Korea. Thus, the practice of intensive cattle husbandry and the regionally different seroprevalence of B. besnoiti infection in cattle in Korea warrant routine monitoring and vector control to reduce economical losses due to bovine besnoitiosis in the country

Prevalence of Salmonella in Slaughter Pigs in South Korea

A total of 177(11.9 %) Salmonella was isolated from 1,483 slaughtered pig samples (784 lymph nodes and 699 caecal contents) in Korea. One hundred forty (17.9 %) and 37 (5.3 %) Salmonella were isolated from lymph nodes and caecal contents, respectively. The major serotypes were as follows; S. Typhimurium (28.2 %), S. Derby (17.5 %), S. Schwarzengrund (15.3 %) and S. Mbandaka (11.9 %). None of the 50 S. Typhimurium isolates were detected the ampicillin or chloramphenicol resistance genes in multipex PCR

Antimicrobial Susceptibility-and-Serotypes-of Salmonella Organisms Recovered from Korean Swine

The present study was carried out to investigate serotype prevalence and antimicrobial susceptibility of Salmonella organisms isolated from slaughter pigs in the republic during 3 years periods from 1998 to 2000. A total of 226 cultures of Salmonella spp. were isolated from ileocecal lymph nodes of 1,403 slaughter pigs from 50 farms, of which 42 farms were infected with the organisms. Among 17 serotypes identified the most prevalent serotypes in order of prevalence were S. Typhimurium, S. Reading, S. Derby, S. Agona, S. Enteritidis, S. Schwarzengrund. Other minor serotypes identified were S. Worthington, S. Senftenberg, S. Saintpaul, S. Bolton and S. Mealegridis

Bacteriology division, Animal and Plant Quarantine Agency

ABSTRACT Background: Haemophilus parasuis is the etiological agent responsible for causing Glässer&apos;s disease in pigs, which are major respiratory pathogens that cause large economic losses in the pig industry worldwide. H. parasuis obtains transferrinbound iron by expressing two surface receptors, transferrin-binding protein A and B (TbpA and B). The TbpA and B are capable of binding to transferrin, and an impairment of iron uptake mechanisms is likely to induce virulence. For this reason, these proteins can be useful as a candidate target for H. parasuis vaccination. Also, the live attenuated Salmonella Typhimurium expressing recombinant antigens from other pathogens are attractive vaccine vectors. Materials, Methods &amp; Results: In this study, we constructed attenuated S. Typhimurium vaccine strain by porcine neurtophil passage method. By the passage, the ability of the neutrophil-adapted isolate to utilize d-xylose was lost, while the ability of the strain to ferment trehalose was delayed after 2 or more days of the culture. The aspartate β-semialdehyde dehydrogenase (asd) gene was eliminated from S. Typhimurium by one-step PCR. Deletion of asd region was confirmed by PCR using primers specific to the endpoints of the targeted region. TbpA fragment was amplified by PCR from genomic DNA of H. parasuis serotype 5. To construct TbpA expression plasmids, tbpA was subcloned downstream from the β-lactamase signal sequence in the multicopy asd + pYA3493 vector. This plasmid was subsequently electrotransformed into attenuated S. Typhimurium. The 636bp fragment of the tbpA gene of H. parasuis in attenuated S. Typhimurium was amplified by PCR and the in-frame fusion of the tbpA was confirmed by nucleotide sequencing. The used this strain with Asd + balanced-lethal plasmid pYA3493 vector to specify recombinant TbpA antigen, conserved immunogenic region of H. parasuis. Expression of the TbpA protein was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. The size of TbpA protein was estimated at about 30kDa. Mice were administered orally in order to evaluate protective efficacy of this vaccine strain against H. parasuis serotype 5. For efficacy test, female ICR mice (5 weeks old) were orally injected, intraperitoneally challenged with a lethal dose (4X10 5 CFU/mouse) of H. parasuis serotype 5, and examined the survival rates compared with vaccination and non-vaccination group. The experiment was terminated two weeks post-challenge. The live attenuated S. Typhimurium conserved pYA3493-TbpA antigen vaccine protected 40% of immunized mice against challenge of H. parasuis serotype 5. This result suggested that the live attenuated Salmonella Typhimurium vaccine expressing TbpA might be protection for Glässer&apos;s disease outbreaks caused by H. parasuis. Discussion: This paper has shown protected mice that attenuated S. Typhimurium strain using pYA3493 expresses TbpA antigen against H. parasuis. Vaccination using bacterins is an efficient way to control outbreaks of Glässers disease, but significant variability has been reported. Therefore, the development of a new vaccine system to prevent Glässers disease using pYA3493-TbpA will avoid the disadvantages of the currently used vaccines. We need further works to enhance protection rate and to determine the potential of the vaccine in pigs

An outbreak of fatal hemorrhagic pneumonia caused by Streptococcus equi subsp. zooepidemicus in shelter dogs

An outbreak of fatal hemorrhagic pneumonia with 70~90% morbidity and 50% mortality occurred in an animal shelter in Yangju, Gyeonggi Province, Korea. Clinically, the affected dogs showed severe respiratory distress within 48 h after arriving in the shelter. The dead were found mainly with nasal bleeding and hematemesis. At necropsy, hemothorax and hemorrhagic pneumonia along with severe pulmonary consolidation was observed, though histopathological analysis showed mainly hemorrhagic bronchopneumonia. Lymphoid depletion was inconsistently seen in the spleen, tonsil and bronchial lymph node. Gram-positive colonies were shown in blood vessels or parenchyma of cerebrum, lung, liver, spleen, and kidney. Also, Streptococcus (S.) equi subsp. zooepidemicus was isolated from the various organs in which the bacterium was microscopically and histologically detected. In addition, approximately 0.9 Kb specific amplicon, antiphagocytic factor H binding protein, was amplified in the bacterial isolates. In this study, we reported an outbreak of canine hemorrhagic bronchopneumonia caused by S. equi subsp. zooepidemicus in an animal shelter in Yangju, Korea

Evaluation of a competitive ELISA for antibody detection against avian influenza virus

Active serologic surveillance is necessary to control the spread of the avian influenza virus (AIV). In this study, we evaluated a commercially-available cELISA in terms of its ability to detect AIV antibodies in the sera of 3,358 animals from twelve species. cELISA detected antibodies against reference H1- through H15-subtype AIV strains without cross reactivity. Furthermore, the cELISA was able to detect antibodies produced following a challenge of the AIV H9N2 subtype in chickens, or following vaccination of the AIV H9 or H5 subtypes in chickens, ducks and geese. Next, we tested the sensitivity and specificity of the cELISA with sera from twelve different animal species, and compared these results with those obtained by the hemagglutination-inhibition (HI) test, the "gold standard" in AIV sera surveillance, a second commercially-available cELISA (IZS ELISA), or the agar gel precipitation (AGP) test. Compared with the HI test, the sensitivities and specificities of cELISA were 95% and 96% in chicken, 86% and 88% in duck, 97% and 100% in turkey, 100% and 87% in goose, and 91% and 97% in swine, respectively. The sensitivities and specificities of the cELISA in this study were higher than those of IZS ELISA for the duck, turkey, goose, and grey partridge sera samples. The results of AGP test against duck and turkey sera also showed significant correlation with the results of cELISA (R-value >0.9). In terms of flock sensitivity, the cELISA correlated better with the HI test than with commercially-available indirect ELISAs, with 100% flock sensitivity

A multiplex real-time PCR for differential detection and quantification of Salmonella spp., Salmonella enterica serovar Typhimurium and Enteritidis in meats

Salmonella (S.) Typhimurium and S. Enteritidis are the major causative agents of food-borne illnesses worldwide. Currently, a rapid detection system using multiplex real-time polymerase chain reaction (PCR) has been applied for other food-borne pathogens such as Escherichia coli, Staphylococcus aureus and Streptococcus spp. A multiplex real-time PCR was developed for the simultaneous detection of Salmonella spp., especially S. Typhimurium and S. Enteritidis, in beef and pork. For the specific and sensitive multiplex real-time PCR, three representative primers and probes were designed based on sequence data from Genbank. Among the three DNA extraction methods (boiling, alkaline lysis, and QIAamp DNA Mini Kit), the QIAamp DNA Mini Kit was the most sensitive in this study. The optimized multiplex real-time PCR was applied to artificially inoculated beef or pork. The detection sensitivity of the multiplex real-time PCR was increased. The specificity of the multiplex real-time PCR assay, using 128 pure-cultured bacteria including 110 Salmonella isolates and 18 non-Salmonella isolates, was 100%, 100% and 99.1% for Salmonella spp., S. Typhimurium and S. Enteritidis, respectively. The sensitivity was 100%, 100% and 91.7% for Salmonella spp., S. Typhimurium and S. Enteritidis, respectively. The multiplex real-time PCR assay developed in this study could detect up to 0.54 ± 0.09 and 0.65 ± 0.07 log10 CFU/ml for S. Typhimurium and S. Enteritidis for beef, 1.45 ± 0.21 and 1.65 ± 0.07 log10 CFU/ml for S. Typhimurium and S. Enteritidis for pork, respectively, with all conditions optimized. Our results indicated that the multiplex real-time PCR assay developed in this study could sensitively detect Salmonella spp. and specifically differentiate S. Typhimurium from S. Enteritidis in meats

Enzyme immunoassay for the rapid detection of Escherichia coli O157

An enzyme immunoassay(EIA) to detect Escherichia(E.) coli 0157 in pork was developed by using a sandwich-type assay on the 96-well microplates. All E. coli O157 strains and Citrobacter amalonaticus reacted strongly, however 29 E. coli serotypes and 15 non-E. coli bacterial strains showed negative in E. coli O157 EIA. E. coli 0157 in pork could be detected with in 13 h including 10 h in enrichment broth and 3 h in EIA. As few as 1.8 CFU of E. coli O157 per g of pork could be detected after enrichment, whereas above 1.8 >. 1 o5 CFU of E. coli O157 per g of pork could be detected without enrichment. The E. coli 0157 EIA was a sensitive, easy-to-perform and efficient method for the screening of E. coliO 157 in pork.</p

Prevalence of Salmonella in Slaughter Pigs in South Korea

A total of 177(11.9 %) Salmonella was isolated from 1,483 slaughtered pig samples (784 lymph nodes and 699 caecal contents) in Korea. One hundred forty (17.9 %) and 37 (5.3 %) Salmonella were isolated from lymph nodes and caecal contents, respectively. The major serotypes were as follows; S. Typhimurium (28.2 %), S. Derby (17.5 %), S. Schwarzengrund (15.3 %) and S. Mbandaka (11.9 %). None of the 50 S. Typhimurium isolates were detected the ampicillin or chloramphenicol resistance genes in multipex PCR.</p