• Korean Journal of Veterinary Research
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• v.63 no.2
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• pp.16.1-16.6
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• 2023

Salmonella spp. are pathogens involved in most salmonellosis in rabbits. This study examined Salmonella disease in rabbits raised in Thua Thien Hue, Vietnam. Two hundred and 56 rectal swabs of rabbits were taken, and a carrier rate of 33.98% was found. In addition, all the isolated Salmonella spp. strains were 100% motile; positive for H₂S, catalase, Voges Proskauer, coagulase, citrate, maltose, and dextrose; and negative for indole, methyl red, urease, oxidase, sucrose, and lactose. The Kirby-Bauer method showed that these Salmonella strains were susceptible to doxycycline (93.2%), tetracycline (84.1%), and levofloxacin (65.9%). On the other hand, they were highly resistant to streptomycin (95.5%), ampicillin (93.2%), colistin (40.9%), and gentamicin (34.1%). Furthermore, polymerase chain reaction used to screen for virulence and specific genes of Salmonella strains showed that all Salmonella strains isolated carried InvA, fimA, and Stn.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.542-544
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• 2023

Methicillin-resistant Staphylococcus pseudintermedius Z0118SP0130 was isolated from eye specimen of a companion dog in South Korea. The complete genome of Z0118SP0130 consisted of a 2,663,277 bp chromosome and there was no plasmid. The strain was identified as the sequence type 45 and contained a mecA gene which comprised of staphylococcal cassette chromosome mec type Vb (5C2&5). Antimicrobial resistance to erythromycin, clindamycin, quinupristin-dalfopristin, trimethoprim-sulfamethoxazole, mupirocin, oxacillin, streptomycin, and gentamicin was observed in the strain.

• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.243-247
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• 2005

Background : The prevalence of tuberculosis is slowly decreasing in Korea. However, the drug-resistance of pulmonary tuberculosis is a major risk factor of treatment failure. Moreover, the National Surveillance System has recently been discontinued. Therefore, a continuous survey is necessary for the exact detection of the rate of drug resistance. We studied the recent 4-year drug resistance rate of tuberculosis at a single University hospital in Seoul. Materials and Methods : The study included 239 pulmonary tuberculosis patients performed with a tuberculosis culture and a drug-sensitivity test at Hanyang University Medical Center from March 1999 to March 2003. Results : Of the 239 patients included in the study during the 4-year period, 52 patients showed resistance to one or more anti-tuberculosis drug (21.8%). The rate of multi-drug resistance was 12.6%. The resistance rates to isoniazid, rifampin, ethambutol, streptomycin and pyrazinamide were 18.4%, 13.8%, 11.7%, 6.7% and 8.4%, respectively. Ninety patients had a history of previous anti-tuberculosis treatment, and the rates of the overall drug resistance and multi-drug resistance of these patients were 36.7% and 25.6%, respectively. The patients with drug-resistance showed a higher rate of a previous tuberculosis treatment history (63.5%) than the drug-sensitive group patients (30.5%). Conclusion : The rate of drug resistant tuberculosis is 21.8%, and multi-drug resistant tuberculosis is 12.6%. The rate of drug resistance is higher in those previously treated for tuberculosis.

• Research in Plant Disease
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• v.24 no.1
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• pp.41-51
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• 2018

Since fire blight disease on apple and pear was produced in Korea in 2015, there were no registered chemicals to control against this disease. Instead, several antibacterial chemicals that were registered for other bacterial diseases such as soft rot and bacterial spot have been authorized by Rural Development Administration (RDA). However, these chemicals are not tested efficacy for fire blight disease except damage by those treatments on apple and pear in Korea. Thus, we evaluated efficiency using in vitro and in planta assays of antibacterial chemicals such as antibiotics and copper compounds including kasugamycin, oxytetracycline, oxolinic acid and streptomycin, and copper hydroxide, copper sulfate, oxine copper and tribasic copper sulfate, respectively. We also tested two kinds of biological agents. As expected, significant antibacterial effect was observed in vitro test of both antibiotics and copper-based chemicals. In planta test based on disease severity including ooze and water-soaked formation on immature pears, bacterial populations on blooms, and blight lesion formation in artificially inoculated shoots, kasugamycin, oxytetracycline and streptomycin have been shown the most efficiency among tested antibiotics. Four copper-based chemicals tested in this study, control effects are little bit lower than agricultural antibiotics but they seem to be available to use in terms of winter season. Biocontrol agents were also shown possibility to treat in eco-friendly farms. In addition, there are no antibiotic resistance genes in Korean isolates against antibiotics, which were selected for suppression of fire blight in this study.

• The Journal of the Korean Society for Microbiology
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• v.13 no.1
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• pp.63-73
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• 1978

28 strains of Enterococci isolated at doctorless areas in Korea from Oct. 1976 through Mar. 1977 and 30 strains of Enterococci isolated at Seoul National University Hospital from Sep. 1976 through Dec. 1976 were examined for susceptibilities to 14 antimicrobial agents by agar dilution method. The susceptibilities of two groups to each antimicrobial agent were compared and incidence of resistant strains in each antimicrobial agent, incidence of multiply resistant strains and correlations in the antimicrobial susceptibility of 58 strains of Enterococci among 14 antimicrobial agents were analyzed. 1. With Tetracycline, Oxytetracline, Doxycycline, Minocycline and Erythromycin, the mean MIC's of Enterococci isolated at Seoul National University Hospital were 1.9-2.5 times higher than those of Enterococci isolated at doctorless areas, though there were no statistical significance. 2. Frequency of resistant strains in Enterococci isolated at Seoul National University Hospital was the highest with Cephalexin(100%), Gentamicin(100%), and Streptomycin(100%), followed by Kanamycin(93.3%), Carbenicillin(90%), Tetracycline(26.7%), Oxytetracycline(26.7%), Doxycycline(26.7%), Minocycline(20%), Erythromycin(10%), Troleandomycin(10%), Penicillin(6.7%), Cotrimoxazole(6.7%) and Ampicillin(0%). 3. Frequency of resistant strains in Enterococci isolated at doctorless areas was the highest with Kanamycin(100%) and Streptomycin(100%), followed by Cephalexin(96.4%), Gentamicin(96.4%), Carbenicillin(92.9%), Tetracycline(10.7%), Oxytetracycline(10.7%), Doxycycline(10.7%), Minocycline(10.7%), Cotrimoxazole(10.7%), Penicillin(3.6%), Ampicillin(0%), Erythromycin(0%), and Troeandomycin(0%). 4. In study with Penicillin, Ampicillin, Tetracycline, Cotrimoxazole, Erythromycin and Troleandomycin, there were no multiply resistant strains in Enterococci isolated at doctorless areas, while 4 strains of Enterococci isolated at Seoul National University Hospital showed multiple resistance. 5. There were high correlation in susceptibility of 58 strains of Enterococci among Tetracycline, Oxytetracycline, Doxycycline and Minocycline(correlation coefficients 0.86-0.97). Correlation coefficients of susceptibility among penicillin analogues(Penicillin, Ampicillin, Carbenicillin and Cephalexin) ranged between 0.75-0.89. Correlation coefficients of susceptibility among aminoglycosides(Kanamycin, Gentamicin and Streptomycin) ranged between 0.09-0.51.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.320-327
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• 2004

Three hundreds thirty two bacterial colonies which were able to degrade crude oil were isolated from soil sam­ples that were contaminated with oil in Daejeon area. Among them, one bacterial strain was selected for this study based on its higher oil degrading ability, and this selected bacterial strain was identified as Acinetobactor sp. B2 through physiological-biochemical tests and analysis of its 16S rRNA sequence. Acinetobactor sp. B2 was able to utilize various carbohydrates but did not utilize trehalose and mannitol as a sole carbon source. Acinetobactor sp. B2 showed a weak resistance to antibiotics such as kanamycin, streptomycin, tetracycline and spectinomycin, but showed a high resistance up to mg/ml unit to heavy metals such as Ba, Li, Mn, AI, Cr and Pb. The optimal growth temperature of Acinetobactor sp. B2 was $30^{\circ}C.$ The lipase produced by Acinetobactor sp. B2 was purified by ammonium sulfate precipitation, DEAE-Toyopearl 650M ion exchange chromatography and Sephadex gel filtration chromatography. Its molecular mass was about 60 kDa and condition for the optimal activity was observed at $40^{\circ}C$ and pH 10, respectively. The activation energy of lipase for the hydrolysis of p­nitrophenyl palmitate was 2.7 kcal/mol in the temperature range of 4 to $37^{\circ}C,$ and the enzyme was unstable at the temperature higher than $60^{\circ}C.$ The Michaelis constant $(K_m)\;and\;V_{max}$ for p-nitrophenyl palmitate were 21.8 uM and $270.3\;{\mu}M\;min^{-1}mg^{-1},$ respectively. This enzyme was strongly inhibited by 10 mM $Cd^{2+},\;Co^{2+},\;Fe^{2+},\;Hg^{2+},$ EDTA and 2-Mercaptoethalol.

• Food Science of Animal Resources
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• v.31 no.1
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• pp.47-53
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• 2011

Salmonella enterica serovar Typhimurium (ST) is one of the most common serovars isolated from humans and animals. It has been suggested that ST infections in Koreans are largely due to the consumption of contaminated pork and beef. To investigate the genotypes, phage types, and antimicrobial resistance patterns for ST isolates of different origins, a total of 70 ST strains, including 19 isolates from humans, 44 isolates from pigs, and 6 isolates from cattle, were analyzed using pulsedfield gel electrophoresis (PFGE), phage typing, and antimicrobial susceptibility tests. Forty-three distinct PFGE patterns were generated from 70 ST isolates, which were grouped into 14 PFGE groups (from A to N) at the level of 75% similarity. The most prevalent group was the A (A1-A17 subtypes) group, encompassing 54.5% (38/70) of ST isolates. ST isolates from pigs and cattle mostly belong to groups A and L, whereas ST isolates from humans mostly belong to groups F and C. Antimicrobial susceptibility tests using 11 antimicrobial agents showed that resistance to tetracycline (TE) (81.4%) was highly prevalent, followed by streptomycin (S) (64.3%) and nalidixic acid (NA) (31.4%) resistance. A total of seventeen antimicrobial resistance patterns were observed. Only 8.6% of isolates, including a reference strain, were susceptible to all antimicrobial agents tested. The most prevalent resistance pattern was TE-S (37.1%), which was seen in 66.6% of bovine, 40.8% of swine and 21.1% of human isolates. Three ST isolates from humans (15.9%) showed resistance to 7-8 antimicrobials. The most predominant phage type (PT) was U302 (64.3%), followed by DT170 (10.0%). PFGE types did not coincide with antimicrobial resistance patterns and phage types; therefore, the combination of those types allowed for further differentiation between tested ST isolates.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.582-588
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• 2016

Seventy-nine Vibrio parahaemolyticus isolates from surface seawater from Gomso Bay, west coast of Korea, were analyzed for the presence of virulence genes and their susceptibility to 30 different antimicrobials. All 79 isolates were examined for the presence of two virulence genes (tdh or trh) using polymerase chain reaction (PCR); however, no isolates possessed either the tdh or trh gene. According to a disk diffusion susceptibility test, all of the strains studied were resistant to oxacillin, penicillin, and vancomycin, followed by ticarcillin (97.5%), ampicillin (96.2%), clindamycin (86.1%), erythromycin (10.1%), streptomycin (7.6%), cefoxitin (6.3%), amikacin (2.5%), and cephalothin (2.5%). However, all of the strains were susceptible to 19 other antimicrobials including cefepime, cefotaxime, chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. All 79 isolates (100%) were resistant to four or more classes of antimicrobials, and two strains exhibited resistance to eight antimicrobial agents. The average minimum inhibitory concentrations (MICs) for V. parahaemolyticus for ampicillin, penicillin, ticarcillin, and vacomycin were 946.5, 1,305.9, 1,032.3, and 45.0 µg/mL, respectively.

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.113-118
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• 1980

Total of 11 strains of Ldctobacillus isolated from lactobacillus-fermented milk and-beverage in March 1980 were examined for susceptibility to 8 drugs, and transferability and transfer frequency of R plasmids by conjugation. Of 11 isolates each 2 strains were classified as L. cellobiosus and L. helveticus, each 1 strain as L. plantarum, L. lactis, L. acidophilus, L. delbrueckii, L. casei subsp. casei, L. casei subsp, tolerans and L. salivarius subsp, salivarius by Bergey's manual. Resistance was the most active to na lidixic acid(NA), followed in decreasing order by chloramphenicol(CP), ampicillin(AP), kanamycin(KM) and streptomycin(SM). All of isolates were resistant to NA, each 10 strains to CP and AP, 7strains to KM and 6 strains to SM, indicating all of the isolates were resistant to two or more drugs in combination. No strain was resistant to erythromycin(EM), penicillin(PC) and tetracycline(TC). The most frequently encountered resistant patterns were CP NA AP SM KM, followed by CP NA AP KM, NA AP, CP NA, CP NA AP and CP NA AP SM in order. Transfer experiment of drug resistance showed that of 11 resistant strains, 9 strains transferred parts of their resistance to AP or AP CP or SM AP, indicating 9 strains carried R plasmids determining R(AP), R(AP CP) and R(SM AP). The conjugal frequency of R(AP) from Lactobacillus to E. coli ranged from 2.5{\times}10^{-1} to $5.6{\times}10^{-4}%$, that of R(CP) ranged from 5.0{\times}10^{-1} to 5.0{\times}10^{-3}% and that of R(SM) ranged from 6.0{\times}10^{-5} to 1.4{\times}10^{-5}%, at $37^{\circ}C$ for 18 hours of incubation.

• Korean Journal of Veterinary Service
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• v.40 no.2
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• pp.119-131
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• 2017

Among different types of spoilage, microbial contamination can cause feed decomposition, which results in decreases in feed intake and productivity, infection, and breeding disorder. During the storage time, various microbes have a chance to inoculate with depreciation of feed and to infect the animals. We investigated bacteria that inhabit diverse feed ingredients and complete feed which have been stored for a few months. We isolated and identified 30 genera and 62 species of bacteria. Among these 62 species, 21 species were of non-pathogenic bacteria, 18 species were of pathogenic bacteria, 9 species were of opportunistic pathogens, and 14 species were of unknown bacteria. Pantoea allii and 24 species showed proteolytic enzyme activity. We also confirmed that 6 species including Pseudomonas psychrotolerans showed ${\alpha}$-amylase activity, and 29 species including Burkholderia vietnamiensis showed cellulase activity. Microbacterium testaceum and 3 species showed resistance to Ampicillin, Kanamycin, Streptomycin, Gentamicin, Carbenicillin, and Erythromycin ($50{\mu}g/mL$). Using mealworm larvae (Tenebrio molitor L.) as a model for pathogenicity, we confirmed that 8 species including Staphylococcus xylosus had pathogenicity for mealworm larvae. Especially, Enterobacter hormaechei, Staphylococcus xylosus, and Staphylococcus hominis were reported as being pathogenic for humans. This research suggests that hygienic management of animal feed is essential because beneficial and harmful bacteria can inhabit animal feed differently during storage and distribution.