• The Korean Journal of Ecology
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• 제17권2호
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• pp.223-235
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• 1994

The transfer of plasmid-borne genes coding for resistance to antibiotics (Ampicillin, Carbenicillin, and tetracycline) among 16 strains isolated from Mankyong River was examined. The survival of donors, recipient, and transformants in sterile and nonsterile soil (the soil was amended with 12% vol/vol with the clay mineral, montmorillonite) was also studied. In sterile soil, the survival was prolonged in the order of donors, transformants, and recipient. The survival of donors, transformants, and recipient increased when the soil was amended with 12% montmorillonite, but not in nonsterile soil. In nonsterile soil, donors survived longer than transformants and recipient, but the survival of transformants and recipient showed no significant differences. The results of these studies suggest that genes can be transferred by transformation, and transferred genes can survive in soil for a considerable time.

• 대한수의학회지
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• 제37권4호
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• pp.773-777
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• 1997

A retrospective study of 132 cases of natural Escherichia coli infection in preweaning piglets with diarrhea submitted to the Department of Veterinary Pathology in Seoul National University from 1995 to 1996 was performed to determine the biochemical characteristics and antibiotics susceptibility. Most field isolates were lysine decarboxylase-positive (99.2%), phenylalanine decarboxylase-negative (100%), and fermented sorbitol (91.7%). Antibiotic susceptibilities will be determined by agar diffusion method. A large percentage of isolates were resistant to many antibiotics in common usage. Most isolates were susceptible to colistin (98.8%), gentamycin (64.3%), amikacin (100%), and ceftiour sodium (64.2%), whereas most isolates were notably resistant to ampicillin (86.9%), neomycin (66.7%), streptomycin (84.5%), tetracycline (98.8%), penicillin (98.8%), and amoxacillin (58.3%).

• 약학회지
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• 제34권1호
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• pp.54-63
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• 1990

These studies were made to assess the present stage of resistance of Shigella species to antibiotics and to find characteristics of R-plasmid of these bacteria. From 1986 to 1988, 125 strains of Shigella species were isolated from patients specimens collected in Chung Cheong-do Hospital, Kyunghee Medical Center, city an provincial health & environmental institutes. These specimens were tested for resistance to 12 kinds of antimicrobial agents by agar dilution method. Using Muller-Hinton agar for the assay of drug resistance and Trypticane Soy Broth as propagating medium for conjugation. All the strains (100%) were resistant to one or more antibiotics. Drug resistance patterns of isolated strains were found as the highest resistance to ampicillin (98%) in 1986, to tetracycline (98%) in 1987, to tetracycline (100%) in 1988, all strains were sensitive to gentamicin, amikacin, tobramycin. Chronologically, resistance decreased gradually as it was shown in relation to kanamycin, rifampicin in 1986, 1987 and 1988, (4%, 2%) (4%, 2%) (0%, 0%) respectively. But, resistance was increased year by year as it was shown in relation to tetracycline, nalidixic acid, streptomycin in 1986, 1987, 1988 (89%, 19%, 45%) (98%, 46%, 71%) and (100%, 58%, 88%). The resistance in correlation to more than 5 drugs, which was 13 strains among 47 strains in 1986, 38 strains among 87 strains in 1987, 23 strains among 26 strains in 1988, was increased gradually. In the transfer test of drug resistance by conjugation methods, the rate which was 3 strains (50%) in 1986, 8 strains (62%) in 1987, 3 strains (100%) in 1988, was increased gradually. When the donor strains were conjugated with the recipient strains, the conjugation rate was high in the multiple resistant strains. The relationships of transferring patterns of drug resistance and molecular weight of R-plasmid were variable. However, only a plasmid which has more than 35 Mgd was transferred.

• 공업화학
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• 제34권3호
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• pp.318-325
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• 2023

The detection of antibiotics in treated wastewater is a global concern as it enters water bodies and causes the development of antibiotic resistance genes in humans and marine life. The study specifically aims to explore the potential of ferrate (VI) in eliminating tetracycline (TCL). The degradation of TCL is optimized with parametric studies, viz., the effect of pH and concentration, which provide insights into TCL elimination. The increase in pH (from 7.0 to 10.0) favors the percentage removal of TCL; however, the increase in TCL concentrations from 0.02 to 0.3 mmol/L caused a decrease in percentage TCL removal from 97.4 to 29.1%, respectively, at pH 10.0. The time-dependent elimination of TCL using ferrate (VI) followed pseudosecond-order rate kinetics, and an apparent rate constant (kapp) was found at 1978.8 L² /mol² /min. Coexisting ions, i.e., NaNO₃, Na₂HPO₄, NaCl, and oxalic acid, negligibly affect the oxidation of TCL by ferrate (VI). However, EDTA and glycine significantly inhibited the elimination of TCL using ferrate (VI). The mineralization of TCL using ferrate (VI) was favored at higher pH, and it increased from 18.57 to 32.52% when the solution pH increased from pH 7.0 to 10.0. Additionally, the real water samples containing a relatively high level of inorganic carbon spiked with TCL revealed that ferrate (VI) performance in the removal of TCL was unaffected, which further inferred the potential of ferrate (VI) in real implications.

• International Journal of Oral Biology
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• 제40권4호
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• pp.189-196
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• 2015

Minimal inhibitory concentration (MIC) is the lowest antibiotic concentration that inhibits the visible growth of bacteria. Sub-minimal inhibitory concentration (Sub-MIC) is defined as the concentration of an antimicrobial agent that does not have an effect on bacterial growth but can alter bacterial biochemistry, thus reducing bacterial virulence. Many studies have confirmed that sub-MICs of antibiotics can inhibit bacterial virulence factors. However, most studies were focused on Gram-negative bacteria, while few studies on the effect of sub-MICs of antibiotics on Gram-positive bacteria. In this study, we examined the influence of sub-MICs of doxycycline, tetracycline, penicillin and amoxicillin on biofilm formation and coaggregation of Streptococcus gordonii, Streptococcus mutans, Actinomyces naeslundii, and Actinomyces odontolyticus. In this study, incubation with sub-MIC of antibiotics had no effect on the biofilm formation of S. gordonii and A. naeslundii. However, S. mutans showed increased biofilm formation after incubation with sub-MIC amoxicillin and penicillin. Also, the biofilm formation of A. odontolyticus was increased after incubating with sub-MIC penicillin. Coaggregation of A. naeslundii with S. gordonii and A. odontolyticus was diminished by sub-MIC amoxicillin. These observations indicated that sub-MICs of antibiotics could affect variable virulence properties such as biofilm formation and coaggregation in Gram-positive oral bacteria.

• 대한수의학회지
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• 제39권6호
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• pp.1106-1111
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• 1999

In a kenel of 62 dogs, 33 were diagnosed as infected dogs Brucella canis by serological test and blood cultures in a large kennel in Chonnam area. Twenty eight of 33 dogs were treated with combined antibiotics therapy consisting of tetracycline and dihydrostregtomycin. After the first treatment, all dogs became abacteremic and serologic titers declined. Abortion due to B canis infection could be prevented by antibiotic therapy during pregnancy. However, sequential antibiotics therapy for 4 weeks did not eradicate B canis from affected bitch. According to results of serological and blood culture tests, effect of antibiotics treatment respectively revealed that 17 of the originally infected dogs were cure with second therapy schedule at 2 months and 27 of that with 6 months after second therapy.

• 미생물학회지
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• 제49권2호
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• pp.146-149
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• 2013

비브리오균은 해양 및 하구 환경에서 상재하는 균으로 그람 음성 간균, 호염성, 비포자형성의 특징을 가지고 있다. 질병과 관련된 균주로는 Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio cholera 등이 있다. 매년 어패류의 섭취 등을 통해 식중독 사고가 빈번하게 발생하고 있으며, 이에 본 연구에서는 서해안 6곳에서 패류를 채취하여 비브리오균의 분포도를 모니터링하고, 이들의 항생제 내성을 분석하였다. 총 120건의 패류를 TCBS 평판배지와 API 20E kit 기법으로 동정하였을 때 23.3%의 시료에서 비브리오균이 검출되었다. 이들 분리균주들의 항생제 내성을 16종의 항생제에 대해 분석한 결과 82.1%가 각각 vancomycin과 ampicillin에 대해 내성을 보였고, rifampin (71.4%)과 cephalothin (53.6%)에 대한 내성비율도 다른 항생제들에 비해 상대적으로 높은 것으로 나타났다. 분리균주들의 항생제 감수성은 chloramphenicol (92.9%), sulfamethoxazole/trimethoprim (92.9%)과 tetracycline (96.4%)에 대해 가장 높았다. 분리균주들의 약 71.4%가 vancomycin과 ampicillin을 포함하여 3개 이상의 항생제에 대해 다중내성을 보였다.

• 한국식품위생안전성학회지
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• 제29권3호
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• pp.228-233
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• 2014

This study was performed to examine antimicrobial resistance of Enterococcus spp. strains from retail raw meat and fish products purchased in 2012. 43 Enterococcus spp. strains were isolated from a total of 207 samples (beef, pork, chicken, fish) with contamination rate of 20.8%. The isolated strains were identified as E. faecalis (22 strains), E. gallinarum, E. hirae (5 strains), E. avium (4 strains), E. faecium (3 strains), E. duram, E. casseliflavus (2 strains). Susceptibility to 10 antibiotics was tested, and the highest resistance was observed to tetracycline. And antimicrobial resistance rates were presented below 20% with most of the other antimicrobial agents. The isolated Enterococci from chicken showed higher resistance also to ciprofloxacin and erythromycin, not only to tetracycline, compared to the isolated Enterococci from beef, pork and fish. Sixteen isolates (37.2%) were sensitive to all antibiotics. Four isolates (9.3%) were resistant to 3 or more antibiotics. Vancomycin-resistant enterococci (VRE) was not identified. According to the results of genetic similarity pattern analysis via PFGE and rep-PCR, Enterococci strains showed different patterns from these collected in 2011. This indicates that there is no genetic similarity among all the strains.

• Food Science and Biotechnology
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• 제16권6호
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• pp.868-872
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• 2007

The microbiological and chemical identification of antibiotic residues was attempted for livestock and seafood products including pork (n=34), beef (n=34), chicken (n=32), flatfish (n=37), armorclad rockfish (n=36), and sea bream (n=27). The meat (n=100) and seafood (n=100) samples were collected from 9 markets in 5 major Korean cities. Antibiotic substances were identified from the classes of tetracyclines, macrolides, penicillins, aminoglycosides, polyethers, peptides, sulfonamides, quinolones, chlorampenicols, and novobiocins using a microbiological assay, the Charm II test and high performance liquid chromatography (HPLC) with ultra violet (UV) and fluorescence detectors. The results showed that 2 tetracyclines (oxytetracycline and tetracycline) and 3 quinolones (ciprofloxacin, norfloxacin, and enrofloxacin) were detected in 4 samples of flatfish among all 100 seafood samples tested. No antibiotic residues were detected in the 100 livestock product samples tested. The amounts (min-max, mg/kg) of the residual antibiotics were as follows; tetracycline 0.78-0.85, oxytetracycline 0.49-0.74, ciprofloxacin 0.09-0.83, norfloxacin 0.01-0.21, enrofloxacin 0.12-2.98. These data indicate that the total detection rate of antibiotics in livestock and seafood products was approximately 2%.

• 한국토양비료학회지
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• 제49권3호
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• pp.242-250
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• 2016

Veterinary antibiotics (VAs) has been used to treat animal disease and to increase animal weight as growth promoter. However, abused usage of VAs can cause production of antibiotic resistance genes (ARGs) in the environment and additionally, residual of VAs in soil can be transferred into crops. Therefore, main objective of this research was to examine bioaccumulation of VAs in sprouts (red cabbage, Brassica Olearacea L. var. Capitata f. rubra and red radish, Raphanus sativus) with hydroponic method. Total of 7 VAs in 2 different classes of VAs (tetracyclcines: tetracycline, oxytetracycline, chlortetracycline, sulfonamides: sulfamethoxazole, sulfamethazine, sulfamethiazole, macrolides: tylosin) were evaluated and experiment was conducted with solid phase extraction (SPE)/high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS). Initial spiked concentration of 7 VAs was $5mg\;L^{-1}$ and cultivation period was 8 days. Result showed that growth of sprouts was inhibited about 23-27% when VAs was introduced. Amount of bioaccumulated VAs was also differed depending on class of VAs. The highest amount of bioaccmulated VAs was tetracycline and sulfamethoxazole in each class with a concentration of 4.05, $7.73mg\;kg^{-1}$ respectively. Calculated transfer ratio of VAs into crops was also ranged 0.38-54.27%. Overall, bioaccumulation of VAs in crops can be varied depending on crop species and class of VAs. However, further research should be conducted to verify bioaccumulation of VAs in crops in the soil environment.