• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.201-210
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• 2017

BACKGROUND: The current study was to monitor of 9 veterinary antibiotics (ceftiofur, clopidol, florfenicol, sulfamethazine, sulfamethoxazole, sulfathiazole, tetracycline, tiamulin, and tylosin) in manure using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive and negative electrospray ionization mode. METHODS AND RESULTS: Sample preparation was carried out using Mcllvaine buffer and citrate salts to adjust the pH of the sample followed by purification with dispersive solid phase extraction (d-SPE). Separation of analytes during LC-MS/MS analysis was conducted using an Eclipse Plus $C_{18}$ column and the mobile phase was in gradient mode with, 0.1% formic acid and 5 mM ammonium formate in methanol (A) and 0.1% formic acid and 5 mM ammonium formate in distilled water (B). The linearity of the matrix-matched calibrations of all tested antibiotics was good, with $R^2$ determination coefficients ${\geq}0.9920$. The limit of detection (LOD) and quantifications (LOQ) were $0.1-67.0{\mu}g/kg$ and $0.4-200.0{\mu}g/kg$, respectively. Analysis of 13 solid and liquid manure samples taken from the Republic of Korea revealed concentrations less than $0.7{\mu}g/kg$ for tiamulin, $1497.6{\mu}g/kg$ for sulfamethazine. CONCLUSION: To monitor 9 veterinary antibiotics from manure samples in 13 provincial areas throughout the Republic of Korea, an analytical method was developed. The developed method was fully validated and successfully applied for monitoring various veterinary antibiotics in manure samples.

• Journal of Life Science
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• v.22 no.8
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• pp.1114-1119
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• 2012

Bacteria are frequently contaminated during the collection and processing procedures of boar semen. Of the contaminants, Stenotrophomonas (S.) maltophilia is a Gram-negative bacterium that is widely distributed in a variety of habitats. Although PCR assays have been developed for the detection of S. maltophilia, they cross-react with some species of Xanthomonas. In this study, we designed a primer set for the detection of S. maltophilia in order to target the chiA (GenBank accession no. NC_010943) gene. The specific PCR products were amplified from S. maltophilia only, not from other tested strains that are frequently found in semen. The detection limit of the PCR was $1.5{\times}10^3$ CFU/ml with pure-cultured S. maltophilia and $1.5{\times}10^4$ CFU/ml with S. maltophilia spiked in semen. Twenty-six (5.9%) S. maltophilia were isolated from 440 semen samples. The PCR results exhibited 98.9% agreement with a comparison of S. maltophilia isolation. Also, the sensitivity and specificity of the PCR were 100% and 98.7%, respectively. In the antimicrobial susceptibility test, S. maltophilia isolates were highly susceptible to enrofloxacin and florfenicol, while the majority of them were resistant to amoxicillin/clavulanic acid, apramycin, ceftiofur, penicillin, and spectinomycin. These results indicated that the PCR using the chiA gene was proven to be reliable and effective for the detection of S. maltophilia with high levels of sensitivity and specificity.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.241-248
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• 2010

The present study was conducted to investigate isolation and antimicrobial resistance ratio of E. coli, E. faecium and E. faecalis from feces(l50 samples) and carcasses (150 samples) on slaughtered pigs from 6 slaughterhouse of 13 cities in the Gyeongnam during the period from January 2009 to December 2009. Isolation ratio of E. coli from feces and carcasses were 98 (65.3%) and 110(73.3%), respectively, and simultaneously, E. faecalis and E. faecium from feces and carcasses were isolated 21 (14%), 52(34.7%) and 18(12%), 14 (9.3%), respectively. All E. coli isolated from feces and carcasses except cefepime (0%) and ceftiofur (0%) were exhibited 2.4~83.6% of resistance to teteracycline (83.6%), ampicillin (68.2%), streptomycin (60%), chloram-phenicol (53.8%) and cephalothin (2.4%). All E. faecalis isolated from feces and carcasses except penicillin(0%) and vancomycin (0%) were exhibited 2.7~80.8% of resistance to teteracycline (80.8%), quinupristin/dalfopristin (78%), erythromycin (56.1%), streptomycin (43.8%) and bacitracin (2.7%). All E. faecium isolated from feces and carcasses except gentamicin (0%), vancomycin (0%), florfenicol (0%), linezloid (0%) and bacitracin (0%) were exhibited 3.1~53.1% of resistance to rifampin (53.1%), erythromycin and tetracycline (25%), penicillin (15.6%), ciprofloxacin (9.3%), and streptomycin, chloramphenicol, and quinupristin/dalfopristin (3.1%). According to the heard size, resistance ratio of E. coli strains isolated from feces and carcasses in slaughtered pigs-breeding farms over 1,500 heard to tetracycline, ampicillin, streptomycin and chloramphenicol showed higher resistance ratio (1.0~16.8%) than those of farms-breeding under 1,500 heard. From the our results, we suggest that a few of antimicrobials were used in the Gyeongnam than the other cities.

• Journal of Life Science
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• v.20 no.5
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• pp.649-654
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• 2010

A total of 68 samples were collected including vaginal mucosa (n=66) from Jangsu stud farm, an equine aborted fetus (n=1), and uterine contents (n=1) from Jeju island. Seventeen Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) strains isolated from horses in Korea were identified as S. zooepidemicus by biochemical tests and sodA.seeI specific multiplex PCR. All isolated strains were divided into 4 clusters: group 1 (No. 2, 3, 5, 6, 7, 11, 12, 13, 14, 15), group 2 (No. 4, 9), group 3 (No. 10, 16, 17), and group 4 (No. 1, 8) by RAPD typing. In group 3, No. 10 isolate that was isolated from vaginal mucosa was indistinguishable from No. 16 and 17 isolates, which were isolated from the equine uterine contents and the equine aborted fetus, respectively. The results of this study suggest that a limited epidemiological relationship exists between the strains from Jangsu (No. 10) and Jeju (No. 16 and No. 17). All isolates showed a high susceptibility to ampicillin, cefoxitin, ceftiofur, cephalothin, florofenicol, gentamicin, nalidixic acid, oxacillin, penicillin, tiamulin, tylosin and vancomycin in antimicrobial susceptibility tests. These results may provide the basic information needed to establish strategies for the treatment and prevention of reproductive diseases in mares in Korea.

• Journal of Veterinary Clinics
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• v.35 no.6
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• pp.258-265
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• 2018

We aimed to identify the relationships between puerperal metritis (PM) and serum metabolites, uterine health, milk yield, and reproductive performance in dairy cows. Blood samples from 150 Holstein dairy cows were collected just after calving, and at 1, 2, and 4 weeks postpartum to measure serum concentrations of ${\beta}$-hydroxybutyrate (BHBA), urea nitrogen, total cholesterol (TCH), albumin, aspartate aminotransferase (AST), calcium, and magnesium. PM was diagnosed by the presence of fever (${\geq}39.5^{\circ}C$) and a watery, fetid uterine discharge during the first 14 days after calving. Cows were divided into two groups on the basis of the presence or absence of the disease: a control group (n = 83) and a PM group (n = 67). The cows diagnosed with PM were subcutaneously administered with 2.2 mg/kg ceftiofur for 3-5 days. The serum concentrations of BHBA tended to be higher (P = 0.06) and AST was higher (P < 0.05) in the PM group than in the control group 1 week after calving, whereas serum concentrations of urea nitrogen, TCH, albumin, calcium, and magnesium were lower (P < 0.05-0.0001) after calving in the PM group than in the control group. The probability of clinical endometritis was higher (odds ratio = 5.40, P < 0.001) in the PM group than in the control group. Moreover, the proportion of neutrophils in the uterus was also higher in the PM group than in the control group 4, 6, and 8 weeks after calving (P < 0.001). The mean milk yield 1 and 2 months after calving was lower (P = 0.05) in the PM group than in the control group. The hazard of pregnancy by 180 days after calving tended to be lower (hazard ratio = 0.60, P = 0.07) in the PM group than in the control group, which led to an extended mean interval between calving and pregnancy (19 days) in the PM group (P < 0.01). In conclusion, PM is associated with higher postpartum concentrations of BHBA and AST, and lower concentrations of urea nitrogen, TCH, albumin, calcium, and magnesium. Moreover, PM is associated with subsequent poor uterine health, lower milk yield, and poorer reproductive performance in dairy cows.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.271-281
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• 2021

Pathogenic Escherichia coli (E. coli) is one among the most important agents of diarrhea in calves. From January to December 2021, 108 isolates from feces of calves with diarrhea were investigated for enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), shiga toxin-producing E. coli (STEC), enteroaggregative E. coli (EAEC), and enteroinvasive E. coli (EIEC) using real-time PCR. In addition, the genes for F5, F17 and F41 fimbriae were detected by PCR. The most frequently isolated pathotypes were EPEC/STEC (29 isolates), and ETEC/EPEC/STEC (29 isolates). ETEC/EPEC, and ETEC/STEC were also found in 10 isolates. EPEC, STEC, and ETEC were detected in 13, 11, and 6 respectively. EAEC, and EIEC was not detected. Antimicrobial resistance test was carried out by agar disc diffusion method with 14 antimicrobials. Among 108 pathogenic E. coli isolates, 107 isolates were resistant to at least one of 14 antibiotics used in this study, 99 (91.7%) were resistant to two or more antimicrobials, and a single remarkable isolate was resistant to 14 antimicrobials. The isolates were primarily resistant to penicillins, streptomycin, tetracycline, ceftiofur, Trimethoprim/sulfamethoxazole, Kanamycin, and Ciprofloxacin. The high rate of resistance in pathogenic E. coli, sometimes to multiple drugs, may complicate future options for treating human infections. These results may bu used for diagnosis and therpeitic purposes in calves with diarrhea.