• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.287-295
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• 1990

The purpose of this study was the examination for presence of pilus antigen, O serogroups, colicin production, antibiotic susceptibility and plasmid profiles among E coli isolated from diarrheal piglets and fattening pigs in Taegu province. Of 145 E coli isolated, 98 strains (67.4%) possesed pilus antigens which belonged to either K88 (47.6%), K99 (11.7%) or 987P (8.3%) types. Fifty-nine strains (40.7%) were classified into tenO serogroups and their types were O8 (22.0%), O20(16.9%), O141(15.3%), O9(10.2%), O45(10.2%), O139(8.5%), O064(6.8%), O149(5.0%), O157(3.4%), and O115(1.7%). Thirty-three strains (22.8%) were colicinogenic and 6 strains (4.1%) were hemolytic. One hundred and thirty-nine strains (95.9%) of 145 E coli isolates were resistant to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, tetracycline, rifampicin and nalidixic acid, alone or in combination thereof. Ninety strains (64.7%) of 139 drug resistant strains carried R factor (R) which were transferable to the recipient by conjugation. In gel electrophoresis for the isolation of plasmid DNA, the number of plasmid DNA band varied from 2 to 11 in 16 E coli with pilus antigen. It's molecular weight ranged from 1.0 to 60.0 megadalton.

• KSBB Journal
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• v.32 no.3
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• pp.199-205
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• 2017

The aim of this study was to investigate probiotic characteristics and fermentation profile of selected lactic acid bacteria (LAB) isolated from traditional fermented foods. Antibacterial activity against various pathogens, acid and bile salt tolerance, cell hydrophobicity, and antibiotic resistance were examined. 16S rRNA sequencing was carried out to identify eight presumptive LAB isolates. In general, all identified LAB (Enterococcus faecium MG89-2, Lactobacillus plantarum MG207, L. paracasei MG310, L. casei MG311, Streptococcus thermophilus MG510, L. bulgaricus MG515, L. helveticus MG585, and L. fermentum MG590) showed strong antimicrobial activity. Also, the selected strains were resistant to bile acid up to 3% and their autoaggregation rates were as high as 60%. All selected strains tested were sensitive to chloramphenicol, tetracycline, and ampicillin, whereas resistant to nalidixic acid and kanamycin.

• Journal of Veterinary Clinics
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• v.22 no.1
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• pp.50-55
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• 2005

We investigated the contamination of animal hospital floor, beauty table, computer keyboard, exam table, operation table and forcep handle by isolations of aerobic bacteria in small animal hospitals in Gwangju. The total number of aerobic bacteria was 52 isolates and Staphylococcus spp. (38 isolates) were the predominant isolates (69.71 %) of them. The prevalent contaminated areas were floor (17 isolates), beauty table (13 isolates) and computer keyboard (9 isolates). The detection of methicillin-resistant (mecA) gene, determined by PCR, showed that 3 of the 17 coagulase-negative Staphylococcus spp. (CNS) isolates possessed the mecA gene. For evaluating the antibiotic susceptibility patterns of the isolates, disk diffusion method was used. The majority of isolates showed high susceptibility to amoxicillin (92.1 %), ceftiofur (84.2%) and polymixin B (73.7%). Also they showed the high resistant to ampicilline (66.7%), penicillin (65%) and kanamycin (56.5%). These results suggest extensive contamination of aerobic bacteria in animal hospital environment.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2004.10a
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• pp.62-65
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• 2004

To protect the watermelon against soil-borne pathogens, we are currently producing disease-resistant transgenic root stock for the growth of watermelon, A defensin gene (J1-1) from Capsicum annum, a ACC deaminase gene from Pseudomonas syringae, a galactinol synthase (CsGolS) gene from Cucumis sativus, and a WRKY (CvWRKY2) gene from Citullus vulgaris were used as transgenes for disease resistance. The gene were transformed into a inbred line (6-2-2) of watermelon, Kong-dae watermelon and a inbred line (GO702S) of gourd, respectively, by Agrobacterium-mediated transformation. Putative transgenic plants were selected in medium containing 100mg/L kanamycin, and then integration of the genes into the genomic DNA were demonstrated by PCR analysis. Successful integration of the gene in regenerated plants was also confirmed by PCR (Figf 1), genomic Southern blot (Fig 2), RT-PCR (Fig 3), and Northern blot analysis(Fig 4). Several T1 lines having different transgene were produced, and disease resistance of the T1 lines are under estimation.

• Korean Journal of Veterinary Research
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• v.23 no.2
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• pp.173-178
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• 1983

This paper deals with the isolation of citrate-utilizing variants of Escherichia coli ($Cit^+$ E. coli) from the animals, their biochemical reactivity and antibiotic susceptibility, and whether the citrate utilizing ability is transmissible. One hundred arid twenty-three isolates of $Cit^+$ E. coli were obtained from cattle and pigs. but from other animals, no isolates were obtaied. Antibiotic susceptibility testing of $Cit^+$ E. coli was performed by the agar dilution method, using the following 9 antibiotics, chloramphenicol(CP), tetracycline(TC), streptomycine(SM), kanamycin(KM), colistin(CL), gentamicin(GM), cephaloridine(CR), aminobenzycillin and nalidixic acid(NA). All the variants tested were susceptible to KM, CL, GM, CR and NA. Of all the variants, 80(65%) were resistant to the drugs tested and resistance to TC and SM was most frequent. The transmission of the ability to utilize citrate on Simmons citrate agar at $37^{\circ}C$ was demonstrated in 78(67.8%) out of the 115 $Cit^+$ E. coli. There were no significant difference in the transfer rates of citrate utilizing ability between resistant and susceptible variants to above 9 drugs. Of 123 isolates, 8 were lost their citrate utilizing ability, spontaneously.

• Korean Journal of Veterinary Research
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• v.32 no.1
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• pp.63-76
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• 1992

A study on the isolation of Yersinia from the feces of healthy pigs and the biotype and serotype and susceptibility to 16 antimicrobials was carried. Out of 853 pigs, Yersiniae were isolated from 349 pigs(40.9%). Of 349 isolates, 289 isolates(82.8%) were Yersinia enterocolitica and 54(15.5%) were Y kristensenii, 3(0.9%) were Y pesudotuberculosis and the rest 3(0.9%) were Y prederiksenii. Out of 289 isolates of Y enterocolitica, the predominants biotype was 3B comprising of 165 isolates(57.1%) and followed by biotype 2, comprising of 49 isolates(17.0%), bioptype 3A, comprising of 41 isolates(14.2%) and biotype 4 comprising of 23 isolates(8.0%). And the predominant serotype was 0 : 3 comprising of 231 isolates(79.9%) and followed by serotype 0 : 9 comprising of 42 isolates(14.5%) and 0 : 21 comprising of 10 isolates(3.5%). Y. enterocolitica were resistant to cephalothin(99%), novobiocin(99%), erythromycine(83%), ampicillin(83%) and carbenicillin(81%) and susceptible to amikacin(100%), colistin(100%), gentamicin(100%), kanamycin(100%), polymyxin B(100%), tobramycin(100%), chloramphenicol(99%), nalidixic acid(99%), neomycin(99%), streptomycin(99%) and tetracycline(99%). Most strains of biotype 2/serotype 0 : 9 were susceptible to carbenicillin(100%) and ampicillin(61%) but the other biotype/serotypes were resistant to these antibiotic.

• Korean Journal of Microbiology
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• v.23 no.2
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• pp.107-114
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• 1985

In order to use for recipient strains of RP4:Mu cts, 5 strainsof Rhizobium were selected among 32 strains, which were isolated and identified in this study. Hybrid plasmin RP4::Mu cts, which, is temperature sensitive and confers resistance to ampicillin, kanamycin and tetracycline was transfered by conjugation from E. coli to other atrains of C. coli and the symbiotic nitrogen fixer, Rhizobium leguminosarum. Transfer frequencies of RP4::Mu cts plasmid from E. coli to Rhizobium were about $10^{-8}-10^{-7}$ in LB agar and YMA media. The transconjugants were confirmed by demonstrating that the drug-resistant and temperature-sensitive clones isolated were drug-resistant and temperature-sensitive clones isolated were capable of releasing phage and forming plaques. The plaque-forming units of transconjugants were about $10^2\;to\;10^3$. Stability test of RP4::Mucts in Rhizobium represented that most of the transconjugants had drug resistance and produce phage Mu cts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1237-1245
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• 1997

Interspecific fusants were made from the cells of two strains of Lactobacillus genus, a streptomycin resistant Lactobacillus sp. JC-7 and a kanamycin resistant L. acidophilus 88. The morphological and physiological properties of the fusants were examined by determining bacteriocin productivity, acid-producing activity, ability of carbohydrates utilization and three important enzyme activities. The fusants produced a bacteriocin against indicator strains and fusant No. 1, 4 exhibited a larger inhibition zone compared to that of L. acidophilus 88. $\beta$-Galactosidase, phospho-$\beta$-galactosidase, lipase activities and resistance to NaCl of Lactobacillus sp. JC-7 were better than those of L. acidophilus 88. Fusant No. 3 and 7 exhibited excellent lipase activities. Protease activity and acid productivity of L. acidophilus 88 were better than those of Lactobacillus sp. JC-7. Proteasse activities of all fusants were higher than those of parental strains, and expecially fusant No. 5 and 7 exhibited excellent proteolysis ability.

• The Journal of the Korean Society for Microbiology
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• v.5 no.1
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• pp.27-31
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• 1970

Nalidixic acid and six other drugs were studied for in vitro effectiveness against 200 strains of Escherichia coli isolated recently from healthy persons and bactericidal activity of ampicillin against one respective strain of Escherichia coli and Salmonella typhi isolated were also studied. The resutlts obtained by the plate dilution method showed the following percentage of resistance: kanamycin, 2.5%; streptomycin, 12.0%; ampicillin, 13.5%; tetracyclin, 15.5%; chloramphenicol, 17.5%; colistin sulfate, 19.5%. No strains were resistant to nalidixic acid, clearly indicating that nalidixic acid is the most effective drug tested. Ampicillin, measured by test-tube diltion method, was highly bactericidal against Salmonella typhi at the concentration of 2.5mcg/ml and against Escherichia coli at 5mcg/ml.

• Korean Journal of Veterinary Research
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• v.15 no.1
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• pp.109-114
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• 1975

A total of 2,065 quarter milk samples of 534 dair cows from 35 herds were examined for mastis and the results obtained were as follows: 1. 654 quarters (31.6%) of 301 dairy cows (56.3%) from 34 herds (97.1%) were infected with mastitis. It was found that 8 cows (1.5%) showed clinical mastitis and other cows were subclinical. 2. Low infection rate of mastis was shown in first delivery cattle and higher infection rate in more deliverable of cattle. 3. The main causative organisms of the matitis were Staphylococcus aureus (19.4%), Streptococcus agalactiae (11.3%) and Streptococcus dysgalatiae (5%). 4. The majority of causative organisms were very resistant to colistin and highly sensitive to tetracycline. Especially Streptococcus strains were highly sensitive to leukomycin, and Staphylococcus aureus were highly sensitive to tetracycline and the other bacteria were highly sensitive to tetracycline and kanamycin.