• 한국환경농학회지
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• 제33권4호
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• pp.409-413
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• 2014

BACKGROUND: Large amount of veterinary antibiotics have been used in the livestock industry to prevent diseases and promote growth. These antibiotics are excreted through feces and urine in unchanged form and reach to agricultural fields via application of the livestock manure based composts. The purpose of this study was to evaluate the occurrence of tetracyclines-resistant bacteria in the soil received livestock manure compost for a long term. METHODS AND RESULTS: Tetracyclines (tetracycline TC, chlortetracycline CTC, and oxytetracycline OTC) resistance bacteria in the soil of rice-onion field applied pig manure compost (PM), in the soil of grass-rye field received cow manure compost (CM), and in the soil of rice field applied inorganic fertilizer (NPK) were determined. The soil received livestock manure composts clearly showed higher number of TC, CTC, and OTC resistance bacteria compared with the soil treated with inorganic fertilizer. The antibiotic resistant bacteria recovered appeared at 80 mg/L of tetracyclines was identified 1 specie, 6 genera 7 species, and 6 genera 7species in the soils received CM, PM, and NPK, respectively. The dominant resistant bacteria with the CM and PM application were Ochrobactrum and Rhodococcus. CONCLUSION: The application of livestock manure compost in the agricultural field is likely to contribute the occurrence of antibiotic resistance bacteria in the agricultural environment.

• Asian-Australasian Journal of Animal Sciences
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• 제14권3호
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• pp.414-422
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• 2001

Antibiotic resistance in human pathogens is a major public health issue. Some of the resistance problem can be attributed to the transfer of resistant bacteria from animals to people and the transfer of resistance genes from animal pathogens and commensal bacteria to human pathogens. Control measures include improvements in food hygiene to reduce the spread of zoonotic bacteria to people via the food chain. However, to specifically address the issue, the medical profession must control misuse and overuse of antibiotics in hospitals and community practice. In addition, the livestock industries and their advisors must reduce and refine the use of antibiotics in animal production and replace antibiotics with alternative disease control measures as much as possible.

• 한국임상수의학회지
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• 제25권4호
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• pp.231-235
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• 2008

Various kinds of antibiotic intramammary infusions are used for treatment of bovine mastitis. As antibiotic-resistant bacteria are increased, the therapeutic rate for bovine mastitis is decreased. The goal of this research is to detect significant synergic effects of combination of antibiotics with sulbactam, $\beta$-lactamase inhibitor, on methicilin-resistant Staphylococcus aureus (MRSA). We used 5 strains of MRSA isolated from bovine mastitis with clinical and subclinical signs. All of the bacteria isolated had resistance to oxacillin and showed multi-resistant patterns in the antimicrobial susceptibility tests. Minimal bactericidal concentrations of ampicillin, amoxicillin, cephalexin, ampicillin/sulbactam(2:1), amoxicillin/sulbactam (2:1), and cephalexin/sulbactam (1:1) were measured according to broth microdilution method suggested by National Committee for Clinical Laboratory Standards (NCCLS, M31-A2) to compare the synergic effects of sulbactam combination with each antibiotic alone. Ampicillin and amoxicillin showed synergic antibacterial activity to 4 and 3 respectively in 5 strains of MRSA in combination with sulbactam. This study demonstrates that ampicillin/sulbactam and amoxicillin/sulbactam can be therapeutic choices for mastitis associated with MRSA.

• 생명과학회지
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• 제8권6호
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• pp.723-728
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• 1998

$\beta$-lactam계 항생물질에 강한 내성을 가지는 세균 Bacillus subtilis J105는 항생물질 존재 하에서 $\beta$-lactamase를 유도생산하여 내성이 더 강해진다. 배지에 항생물질이 존재하지 않을 때는 내성을 유도하는 $\beta$-lactamase의 생산은 15시간 만에 plateau에 달했다. 그러나 배지 중에 ampicillin(500$\mu\textrm{g}$/$m\ell$)이 존재할 때는 배양 25시간 만에 효소 생산이 plateau에 달하나 항생물질 비존재시와 비교하면 효소 활성은 약 20배인 2,900 units/$m\ell$나 많이 생산하는 것을 알 수 있었다. 또한, ampicillin 처리한 것과 무처리 균주를 여러 $\beta$-lactam계 항생물질에 적용하여 MIC를 비교해 본 결과 ampicillin 처리 균주의 MIC가 2~27배 가량 높은 것을 알 수 있었다. 이것은 본 균주가 ampicillin 처리함으로서 $\beta$-lactamase 생산을 유도하여 내성을 증가시킨 것으로 사료된다. 본 내성균주는 penicillin뿐만 아니라 cephalosporin계 항생물질에 대해서도 $\beta$-lactamase 생산을 유도하는 것을 알았다. 그 중에서도 300$\mu\textrm{g}$/$m\ell$의 cloxacillin이 효소생산유도에 가장 최적 농도였다. 항생물질 첨가 시기를 균의 생육시 기별로 조사한 결과 대수증식기가 가장 효과적인 결론을 얻었다. 이상의 결과로 본 내성균주는 다양한 $\beta$-lactam계 항생물질에 의하여 내성이 강하게 유도되는 특이적인 균주임을 시사한다.

• Archives of Pharmacal Research
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• 제26권8호
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• pp.638-643
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• 2003

Raw milk samples, and cow and chicken intestines were tested to isolate vancomycin-resistant, gram-positive bacteria. From these samples, we isolated seven vancomycin-resistant Streptococcus equinus, two vancomycin-resistant viridans Streptococcus and two vancomycin-resistant Enterococcus faecium. The MICs of several antibiotics, including vancomycin, against these strains were tested. Seven isolates of S. equinus showed high level resistance to vancomycin and teicoplanin (＞100 $\mu$ g/mL). The cell wall thickness of these strains was compared with that of the sensitive strain by TEM and no differences were obserbed between these strains. We compared the strains of vancomycin-resistant Streptococcus equinus using PCR with Microbial Uniprimer Kit. We concluded that it is necessary to combine other methods in order to cluster and identify all isolates of S. equinus.

• 한국환경농학회지
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• 제42권4호
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• pp.269-278
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• 2023

Antibiotics either kill or inhibit the growth of bacteria. However, antibiotic-resistant bacteria are difficult to treat with antibiotics. Infections caused by such bacteria often lead to severe diseases. Antibiotic resistance genes (ARG) can be horizontally transmitted across different bacterial species, necessitating a comprehensive understanding of how ARGs spread across various environments. In this study, we analyzed the plasmid sequences of 33 extended-spectrum beta-lactamases (ESBL) producing Escherichia coli isolated from pigs, farms, and their owners. We conducted an antibiotic susceptibility test (AST) with aztreonam and seven other antibiotics, as well as whole genome sequencing (WGS) of the strains using MinION. Our results demonstrated that the plasmids that did not harbor ARGs were mostly non-conjugative, whereas the plasmids that harbored ARGs were conjugative. The arrangement of these ARGs exhibited a pattern of organization featuring a series of ARG cassettes, some of which were identical across the isolates collected from different sources. Therefore, this study suggests that the sets of ARG cassettes on plasmids were mostly shared between pigs and their owners. Hence, enhanced surveillance of ARG should be implemented in farm environments to proactively mitigate the risk of antibiotic-resistant bacterial infections.

• 대한환경공학회지
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• 제33권7호
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• pp.492-500
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• 2011

육상양식장에서 항생제에 대한 내성을 가진 균을 분리하여 다양한 항생제에 대한 내성특성을 확인하고, 전자빔의 조사에 따른 내성균의 항생제 내성 특성변화와 살균효능에 관한 연구를 수행하였다. 메기, 송어, 뱀장어, 미꾸라지양식장의 배출수에서 분리된 균주 중 Aeromonas sp., Citrobacter sp., Bacillus sp., Marinobacter sp., Pantoea sp., Pseudomonas sp., Enterobacter sp.가 다제내성균으로 확인되었다. 양식장 배출수에서 분리한 균주 중 한가지의 항생제 내성을 가지고 있는 균은 41.7%이며, 2가지 이상의 항생제 내성을 가지고 있는 균은 58.3%로 나타났다. Quantitative Structure Analysis Relationship (QSAR) model에 의한 평가는 실험값과 매우 유사하여 독성 평가의 간접적인 지표로 이용될 수 있음을 알 수 있었다. 항생제 내성균에 대해 전자빔을 조사한 결과 1 kGy 이내의 선량에서 살균효율이 99.9%로 강한 살균력을 확인할 수 있었다.

• 약학회지
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• 제30권1호
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• pp.51-54
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• 1986

Fecal samples from Kim-Hae farm animals were examined for the frequency of gram-negative enteric organisms resistant to tetracycline, streptomycin, or penicillin. The propertions of antibiotic resistant to total organisms in fecal specimens of poultry, swine and cow were as follows: 95%, 92%, 70% for tetracycline, 100%, 27%, 9% for streptomycin, 18%, 1%, 1% for penicillin, respectively. The bacteria had multiresistance to antibiotics. These strains had more than one plasmid. From the transformation study, it was concluded that the resistance to streptomycin was attributed to one of these plasmids.

• Natural Product Sciences
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• 제14권2호
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• pp.138-142
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• 2008

The composition of essential oils from Chrysanthemum zawadskii var. latilobum and C. indicum were analyzed and compared. The results of gas chromatography-mass spectrometry revealed there were distinctly different compositional patterns between C. zawadskii var. latilobum and C. indicum essential oils. The combinatorial effect of the oil of C. zawadskii var. latilobum and C. indicum, with various antibiotics was assessed against antibiotic-susceptible and -resistant strains of Staphylococcus aureus and Streptococcus pneumoniae. The essential oil fraction significantly inhibited most of the tested antibiotic-susceptible and -resistant strains of S. pneumoniae, with minimum inhibiting concentrations (MICs) ranging from 0.5 to 4.0 mg/ml. The fractional inhibiting concentration indices (FICIs) of the oils when combined with antibiotics against S. aureus and S. pneumoniae ranged from 0.26 to 0.75, and showed synergistic or additive effects.

• 대한족부족관절학회지
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• 제25권2호
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• pp.100-107
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• 2021

Purpose: The present study aimed to develop guidelines regarding initial choice of antibiotics for diabetic foot ulcers (DFU) by investigating bacterial isolates. Materials and Methods: This study included 223 DFU patients that visited a single tertiary hospital and underwent bacterial culture between January 2016 and February 2020. The study was conducted in two parts: 1) to compare bacterial isolates and wound healing according to comorbidities such as chronic kidney disease (CKD) and peripheral artery disease (PAD), and 2) to compare bacterial isolates according to wound depth using the Wagner classification. Results: Of the 223 patients, 43 had CKD (group A), 56 had PAD (group B), 30 had CKD and PAD (group C), and 94 had none of these comorbidities (group D). The isolation rate for multidrug-resistant gram-negative bacteria (MRGNB) and gram-negative to gram-positive bacteria ratio were highest in group C (p=0.018, p=0.038), and the proportion that achieved wound healing was lowest in group C (p<0.001). In the second part of the study, subjects were classified into 5 grades by wound depth using the Wagner classification; 13 grade I, 62 grade II, 60 grade III, 70 grade IV, and 17 grade V. No significant difference was observed between these grades in terms of isolation rates or gram-negative to gram-positive bacteria ratios. Conclusion: This study suggests antibiotics that cover gram-negative bacteria including MRGNB produces better results in the presence of CKD and PAD and that initial antibiotic choice should be based on the presence of CKD and PAD rather than wound depth.