• Korean Journal of Veterinary Research
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• v.45 no.1
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• pp.75-83
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• 2005

The purpose of this study was to investigate the antibiotic resistance pattern of E. coli and Salmonella spp. isolated from chicken feces. One hundred and forty-seven E. coli isolates showed resistance to tetracycline (95.2%), erythromycin (89.2%), ampicillin (70.1%), streptomycin (59.2%), cephalothin (56.5%), sulfamethoxazole/trimethoprim (53.7%), ciprofloxacin (57.1%), enrofloxacin (59.2%) and norfloxacin (57.1%). The multiple resistance was seen in 144 isolates (97.9%) and the rate of five, six and seven drugs resistance pattern were 20.4%, 18.4% and 16.3%, respectively. Also, the multiple resistance of E. coli to twelve drugs were seen in 1 isolates (0.7%). Fourteen Salmonella spp. showed resistance to ampicillin (50.0%), streptomycin (57.1%), erythromycin (64.3%) and tetracycline (57.1%) and the rate of two and three drugs resistance pattern were 4 isolates (28.6%), respectively. The prevalence of resistant organisms in Korea probably reflects lack of proper antibiotic policy resulting in prolonged and indiscriminate use of antimicrobial agents.

• Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.97-100
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• 2006

To determine whether the tetracycline resistance genes tet (34), tet (M), and tet (S) can be transferred among bacteria, we used a filter mating experiment allowing intimate cell-cell contact between donor and recipient. The tet(34) gene, conveyed on a chromosome of Vibrio species (No. 6 and SW-42) was not transferred to Escherichia coli JM109, suggesting that it is not transferred among bacterial species. The tet (M) gene was transferred from three Vibrio strains (4-E, SW-18, and SW-38) to E. coli at frequencies of $8.5{\times}10^{-5}\;to\;2.1{\times}10^{-6}$. The tet(S) gene was transferred from Lactococcus garvieae KHS98032 to E. coli at a frequency of $1.8{\times}10^{-6}$. Transconjugated recipients showed increased minimum inhibitory concentrations against oxytetracycline. Although the donors possess the Tn916-Tn1545 transposons, they were not detected in transformed recipients, suggesting that the transfer of tet(M) and tet(S) is mediated by elements or mechanisms. Two ribosomal protect protein genes were also transmissible from marine bacteria to E. coli, suggesting gene hopping among marine, terrestrial, and human environments.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.118-125
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• 2013

Antibiotic susceptibility was examined for 596 Salmonella isolates from patients with acute gastroenteritis during 2000-2009 in Gwangju area in South Korea. Of 16 antibiotics tested, ampicillin resistance (43%) was the most commonly observed resistance among the 596 Salmonella sp. isolates, followed by tetracycline (35.9%), nalidixic acid (31.5%), and chloramphenicol (26.2%). Antibiotic resistance varied among serotypes: The highest resistance of S. Enteritidis and S. Typhimurium was to ampicillin (51.1%) and tetracycline (77.9%), respectively. A total of 89 resistance patterns were observed, and 26% (155/596) of Salmonella isolates were susceptible to all antibiotics tested in this study. About 21% (127/596) and 15% (87/596) of the isolates were resistant to one and two antibiotics, respectively. The rest of Salmonella isolates (227/596, 38%) were resistant to three or more antibiotic agents. The highest multi-drug resistance (MDR) was observed in serotype S. Paratyphi B (76.5%), followed by S. Typhimurium (58.2%), and S. Enteritidis (40.2%). The most common resistance pattern of MDR isolates was ampicillin-chloramphenicol-nalidixic acid-ticarcillin (36/227, 15.8%), most of which (35/36, 97.2%) were S. Enteritidis.

• Journal of Microbiology
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• v.43 no.3
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• pp.251-256
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• 2005

In this study, we assessed the susceptibility of 12 Lactobacillus strains, all of which had been isolated from the gastrointestinal tracts of chicken, to three antibiotics (chloramphenicol, erythromycin and tetracycline) used commonly as selective markers in transformation studies of lactic acid bacteria. Among these strains, $17\%,\;58\%,\;and\;25\%$ were found to exhibit a high degree of resistance to $200\;{\mu}g/ml$ of tetracycline, erythromycin, and chloramphenicol, respectively. Seven of the 12 Lactobacillus strains exhibiting resistance to at least $50\;{\mu}g/ml$ of chloramphenicol or erythromycin, and five strains exhibiting resistance to at least $50\;{\mu}g/ml$ of tetracycline, were subsequently subjected to plasmid curing with chemical curing agents, such as novobiocin, acriflavin, SDS, and ethidium bromide. In no cases did the antibiotic resistance of these strains prove to be curable, with the exception of the erythromycin resistance exhibited by five Lactobacillus strains (L. acidophilus I16 and I26, L. fermentum I24 and C17, and L. brevis C10). Analysis of the plasmid profiles of these five cured derivatives revealed that all of the derivatives, except for L. acidophilus I16, possessed profiles similar to those of wild-type strains. The curing of L. acidophilus I16 was accompanied by the loss of 4.4 kb, 6.1 kb, and 11.5 kb plasmids.

• Journal of Life Science
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• v.21 no.2
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• pp.257-264
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• 2011

Seventy five methicillin- resistant Staphylococcus aureus (MRSA) strains and 24 methicillin- susceptible S. aureus (MSSA) were isolated from clinical specimens obtained from a hospital in Suncheon, Jeonnam province, Korea, from July to December, 2009. Antibiotic resistance was determined using the disc diffusion method. Genes encoding enterotoxin (SE), toxic shock syndrome toxin-1 (TSST-1), exfoliative toxin (ET) and Panton-Valentine leukocidin (PVL) were detected by multiplex PCR-mediated amplification using specific primers. Sixty (80%) MRSA isolates possessed either one or more toxin genes and the most common pattern that coexisted in MRSA was seb, sec, seg, sei and tst (22.7%) followed by coexistence of sec, seg, sei and tst genes (18.7%). Gene pvl encoding leukocidin was not found. Significant correlation between the production of sec, seg, sei and tst genes was found. MRSAs were resistant to erythromycin (89% of the isolates), gentamicin (70.7%), ciprofloxacin (69.3%), clindamycin (61.3%) and tetracycline (58.7%), while MSSAs were susceptible to the antibiotics with the exception of erythromycin. Toxin genes seb, sec and tst were related to the tetracycline resistance of MRSA.

• Korean Journal of Veterinary Research
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• v.12 no.1
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• pp.85-89
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• 1972

The minimum inhibitory concentration (MIC) of five chemotherapeutic agents (penicillin, streptomycin, tetracycline, oxytetracycline and furazolidone) was measured for 126 strains of Staphylococcus aureus isolated from the udder of dairy cattle. The results obtained were as follows: 1. The MIC of penicillin, streptomycin, tetracycline, oxytetracycline and furazolidone ranged from 0.03 to 32 ug/ml, 0.06 to 128 ug/ml, 0.06 to 128 ug/ml, 1.0 to 512 ug/ml, and 0.06 to 32 ug/ml, respectively. The most frequent MIC of the above drugs were; penicillin 0.5ug/ml, streptomycin 1.0ug/ml, tetracycline 0.5ug/ml, oxytetracycline 4.0ug/ml, and furazolidone 2.0ug/ml. 2. The number of strains resistant to penicillin. streptomycin, tetracycline and oxytetracycline were 89(70.6), 9(7.1%), 10(7.9%), and 26(20.6%), respectively. Twenty-eight (29.2%) strains showed multiple resistance to more than two antibiotics tested.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.834-846
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• 2017

Aquaculture practices to ensure greater production, such as high density breeding and excessive feeding, are become stressors that raise the prevalence of diseases. Accordingly, increasingly large volumes of antibiotics are used more frequently each year. Long term use antibiotics can generate resistant bacteria, which interrupt treatments and cause a potential transfer to human bodies. Thus, antibiotic resistance is of importance in public health. Tetracycline (Tc) is one of the typical medicines used in the aquaculture drugs, which has a wide range of application including gram-positive and gram-negative bacteria. In the examination of 153 strains isolated from olive flounder (Paralichthys olivaceus) farms located in Jeju in 2016, it turned out that a total of 84 strains were resistant to Tc or oxytetracycline (OTC). The extent to which the strains are resistant to Tc and OTC was confirmed through MIC test, mostly within the range of 25 to $100{\mu}g/m{\ell}$. Twelve different types of tet genes were detected using single and multiplex PCR in the 84 Tc-resistant strains. The PCR was used to find tet(K), tet(M), tet(O), and tet(S), which are known to exist primarily in gram positive strains. According to the results, - tet(S) is the most dominant gene in 49 strains of Streptococcus parauberis, accounting for 63.2%. And there were two strains that have two different types of resistant genes. The multiplex PCR was used to detect tet(A), tet(B), tet(C), tet(D), tet(E), and tet(G), which are commonly found in gram-negative strains. Each of tet(B), tet(D), and tet(B)&(M) was found in a strain presumed to be Vibrio sp., and only tet(D) was found in 10 Edwardsiella tarda strains.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.299-305
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• 2002

Clinically isolated Salmonella Enteritidis strain has a multi drug resistance plasmid, which confers ampicillin, chloramphe-nicol, sulfonamide, streptomycin and tetracycline, named pCAST2. We cloned a 7 kb Sacl fragment of pCAST2 which has sulfonamide, streptomycin and tetracycline resistance genes. The 7 kb SacI fragment showed the organization of sulII-strA-strB-tetR-tetA gene cluster which is different from the other clusters reported previously. In this study, we presented the method to detect this cluster by PCR analysis and showed that this cluster was found in Salmonella strains occurred sporadically at Kyungpook province in 2002.

• Korean Journal of Veterinary Research
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• v.17 no.1
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• pp.1-4
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• 1977

Two hundred and twenty-seven strains of Escherichia coli isolated from 25 hens (12 hens received tetracycline neomycin and sulfadimethoxine, and 13 hens not received antibiotics) were studied for the drug resistance and distribution of R factors. About 74 per cent of E. coli strains isolated from hens of a herd received antibiotics were resistance to tetracycline (TC) streptomycin (SM), chloramphenicol (CM), kanamycin (KM), ampicillin (AP) and sulfisomidine (Su), alone or in combination thereof, but only a hen among a herd not received antibiotics excreted E. coli resistant to TC and SM. Among resistant strains, about 7% were found to be resistant to TC and SM, whereas 93% were resistant to three or more antibiotics. The most common pattern was the quadruple resistant to SM, TC, KM and Su (28.7%), and followed by triple ones to SM, TC and Su (25.3%), and SM, TC and KM (24.7%). About 84% of resistant strains carried R factors which were transferable to the recipient by conjugation.

• YAKHAK HOEJI
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• v.33 no.2
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• pp.73-79
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• 1989

One hundred and sixteen strains of E. coli isolated from drainage in Seoul city in 1987 and 104 strains of E. coli isolated from stools of domestic animals in suburb of Seoul in 1987 were examined for susceptibilities to 10 antimicrobial agents by the agar dilution method. The susceptibilities of the two groups to each antimicrobial agent were compared and correlations in the antimicrobial susceptibility of the 220 strains of E. coli among the 10 antimicrobial agents were also analyzed. The frequency of resistance strains was highest to tetracycline with 77%, and followed by chloramphenicol, streptomycin, ampicillin, kanamycin and cephalosporin in the descreasing order, tanging from 62% to 10%. Strains resistant to tobramycin, nalidixic acid, gentamicin and amikacin occupied 3 strains, 2 strains, 2 strains and 1 strain respectively.