• Childhood Kidney Diseases
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• 제19권2호
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• pp.148-153
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• 2015

Purpose: We investigated trends in antibiotic resistance for gram-negative bacteria in infants with a urinary tract infection (UTI) over 15 years at a single institution. Methods: A retrospective chart review was conducted for children younger than 24 months who visited the emergency room and were diagnosed with a UTI between January 2000 and December 2014. We selected urine culture data that grew Escherichia coli and Klebsiella pneumoniae. Baseline clinical information and results of antimicrobial susceptibility tests were analyzed by dividing the 15-year study time frame into three periods (A: 2000-2004, B: 2005-2009, and C: 2010-2014). Results: During the study period, 478 applicable children were identified (E. coli, 89.7% and K. pneumoniae, 10.3%). Antibiotic resistance to third-generation cephalosporins was increased from period A to period C (A, 2.1%; B, 8.3%; C, 8.8%; P=0.025). Resistance to quinolones also showed a steady pattern during periods A to C, although it was not statistically significant (A, 7.9%; B, 9.7%; C, 12.4%; P=0.221). The incidence of Extended-spectrum ${\beta}$-lactamase (ESBL)-producing gram-negative bacteria increased from period A to period C (A, 1.4%; B, 7.6%; C, 8.2%; P=0.012). Conclusion: This study revealed that the common uropathogens E. coli and K. pneumoniae experienced increasing resistance rates against third-generation cephalosporins and a constant antibiotic resistance to quinolones in children younger than 24 months. We also showed a recent increased incidence of ESBL-producing gram-negative bacteria in patients with community-acquired UTIs. Therefore, it is necessary to actively surveil resistance in order to properly select empirical antibiotics.

• 한국미생물·생명공학회지
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• 제36권4호
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• pp.360-365
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• 2008

식품 내의 잔류 항생물질의 검사는 주로 미생물의 생육 억제 여부를 통한 생물학적인 분석을 이용한다. 이러한 방법은 여러 가지 계열의 항생제들에 대한 미생물의 민감성을 토대로 이용되고 있다. 그러나 현재 사용하고 있는 미생물들로는 동물용의약품으로 허가되어 식용동물에 사용되고 있는 점점 다양해지는 항생제 및 합성항균제를 식품에서 모두 검출할 수는 없다는 한계가 있다. 그러므로 본 연구는 검출 가능한 항생제 및 합성항균제 계열의 범위를 확대하고, 각 약품별 감도를 증진시키기 위한 새로운 방법들을 조사하였다. B. megaterium ATCC 9885, B. subtilis ATCC 6633, B. cereus ATCC l1778 and Geobacillus stearothermophilus (B. stearothermophilus) ATCC 10149를 사용한 검사의 민감성은 macrolides, quinolones와 monensin, chloramphenicol에 대한 검출 감도가 낮았다. 반면에 M. luteus(K. rhizophila) ATCC 9341는 macrolides에 대한 높은 검출 감도를 나타냈고, E. coli ATCC l1303는 quinolones와 aminoglycosides에 대한 높은 민감성을 나타냈다. 결론적으로, 두 균주의 추가로 검출가능한 항생제 및 합성항균제의 범위를 확대하였으며, 검출감도를 높일 수 있게 되었다.

• 한국식품위생안전성학회지
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• 제38권4호
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• pp.193-201
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• 2023

WHO에서는 항생제 사용으로 인한 위해를 줄이고 사람의 건강을 지키기 위한 목적으로, 더욱 신중하게 사용해야 하는 항생제를 '중요 항생제'로 분류하였다. 중요 항생제 선정은 2가지 기준으로 분류하였는데, 기준 1은 사람에서 심각한 세균 감염을 치료하기 위하여 유일한 또는 치료제가 제한적인 항생제 계열, 기준 2는 세균이 비인체 유래로부터 사람으로 감염된 경우 또는 세균이 비인체로부터 내성유전자를 획득할 가능성이 있는 경우이다. 그 결과 '매우 중요한 항생제(Critically important antimicrobials, CIA)', '중요도 높은 항생제(Highly important antimicrobials, HIA)', '중요항생제(Important antimicrobials, IA)' 등 3개 그룹으로 분류되었다. 특히, 매우 중요한 항생제 중에서도 관리의 우선순위가 높은 항생제를 '최우선 중요 항생제(Highest priority critically important antimicrobials, HPCIA)'로 재분류하였는데, 여기에는 3세대 이상 Cephalosporins, Macrolides, Quinolones, Glycopeptides 및 Polymyxins가 속하였다. 중요 항생제 목록은 많은 국가에서 항생제의 올바른 사용과 내성 감소를 위한 위해평가 및 위해관리 정책 등 다양한 분야에 과학적 근거를 제공하며, McDonalds, KFC 등 식품산업 분야에서도 식품안전을 위하여 중요 항생제 목록이 활용되고 있다. 중요 항생제 목록(CIA list)는 앞으로도 새로운 연구 결과를 반영하여 지속적으로 보완될 것이다. 국내에서도 우리의 항생제 내성에 대한 조사결과 등을 신중하고 면밀하게 검토하여 우리 실정에 적합한 목록을 개발함으로써 식품안전성을 확보해 나가는 것이 필요할 것으로 생각된다.

• Archives of Pharmacal Research
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• 제21권6호
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• pp.671-676
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• 1998

Five hundred and seventy clinical strains of Pseudomonas aeruginosa were isolated from August 1993 to August 1994 in Korea and screened for their resistance to ciprofloxacin, norfloxacin, and ofloxacin. Among these, two P. aeruginosa strains (PA150 and PA300) were selected based on their strong resistance (MICs > 50mcg/ml) to all three quinolones. The susceptible strain as well as two resistant strains had proton gradient-dependent efflux system. Efflux system in PA300 showed different specificities to ofloxacin and ciprofloxacin while PA150 had less permeability for ofloxacin. Ofloxacin had a less inhibitory action on DNA synthesis in permeabilized cells of PA150 and PA300 than 1771M. When quinolone resistance determining region (QRDR) in gyrA was sequenced, PA300 had one missense mutation, Asn 116Tyr, which was newly reported in this work. The results showed that PA150 became ofloxacin resistant by reduced ofloxacin accumulation due to the existence of efflux system and low permeability, while resistance of PA300 was due to the efflux system and a mutation in QRDR of gyrA -the target site of quinolone.

• Biomolecules & Therapeutics
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• 제6권1호
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• pp.63-72
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• 1998

-4-Quinolone antibiotics (pefloxacin, ciprofloxacin, norfoxacin, ofloxacin and enoxacin) were tested for mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537, TA1538 and TA102, for chromosomal aberrations in cultured Chinese hamster lung (CHL) cells, and for wing somatic mutations and recombinations (wing spot) in Drosophila. Five 4-quinolones did not show any mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537 and TA1538. However, they were mutagenic inSalmonella typhimurium TA102 with and without metabolic activation in both plate incorporation method and preincubation method. Ciprofloxacin induced structural chromosome aberrations in CHL cells both with and without metabolic activation, and the frequencies were 6% and up to 28%, respectively. Pefloxacin showed equivocal evidence, however, norfloxacin, ofloxacin and enoxacin did not induce the structural chromosome aberrations both in the presence and absence of metabolic activation. In the wing spot assay in Drosophila, ofloxacin increased the frequency of small single spots significantly in a dose-dependent manner but there was no dose-dependent increase of single or twin spots in the others.

• 분석과학
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• 제12권1호
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• pp.22-27
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• 1999

Quinolone계 항균제의 일종인 pefloxacin을 넙치에 투여한 후, HPLC를 이용하여 약물의 분포도를 살펴보았다. 100 mg/kg의 pefloxacin을 넙치에 이틀 연속 경구투여한 후, 넙치의 혈액, 근육 및 간을 포함한 8개의 장기를 분석한 결과, pefloxacin은 장을 통하여 흡수되며 담낭에 축적됨을 알았다. 약물 투여 후 45분에 $4.70{\mu}g/ml$로 혈액내 농도가 최대치를 나타냈으며, 11일째에는 $0.31{\pm}0.01{\mu}g/ml$이 검출되었다. 근육조직에서는 10일째까지 $0.29{\pm}0.02{\mu}g/g$ tissue가 잔류하였다.

• 한국동물위생학회지
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• 제43권1호
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• pp.17-21
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• 2020

It was carried out to investigate the antibiotic residues detected by the residue tests for edible tissues of slaughtered livestock in Korea from January to November in 2019. Positive cases of qualitative test and analytical test for 11 months were 689 and 341, respectively. Positive cases of analytical test for cattle, pigs, horses and poultry were 164, 168, 2 and 7, respectively. Antibiotics were detected from 472 materials from 341 cases and classified as β-lactams 162 (37.9%), aminoglycosides 141 (33%), quinolones 69 (16.2%), sulfonamides 23 (5.4%), amphenicols 10 (2.3%), tetracyclines 9 (2.1%), macrolides 6 (1.4%) and the rest 7 (1.4%). Other materials were benzyl penicillin 119 (27.9%), (dihydro)streptomycin 105 (24.6%) and enrofloxacin (including ciprofloxacin) 39 (9.1%). In conclusion, strict management of benzyl penicillin and streptomycin in cattle and pigs should be implemented to reduce the positive cases of slaughtered livestock in Korea.

• 한국수의병리학회지
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• 제1권1호
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• pp.40-45
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• 1997

The phototoxic potentials of LB20304a a new quinolone compound being developed by LG Chemical Ltd, and reference compounds (Ciprofloxacin; CPFX, Enoxacin; ENX and Lomefloxacin; LFLX) were compared in a murine model. in addition photostability of these compunds was studied after irradiation with long-wave UV light(UVA, 0, 0.3 1 or 3 Joule/$Cm^2$) When hairless mice(9 to 11 weeks old 19-26g) were orally administered with different dose levels of test compunds and exposed to UVA(40J/$cm^2$) inflammatory reactions were observed in a dose dependent manner. Among the compounds tested, LB20304a demonstrated the least phototoxic effects and showed no inflammatroy lesions at a dose level of 100mg.kg (Low dose). ENX and LFLX demonstrated much greater phototoxic reactions while CPFX showed similar or slightly greater phototoxic reactions compared to LB20304a. Similar to the in-vivo results the solutions of LB20304a and CPFX irradiated with UVA demonstrated reduced spectral changes compared to those of ENX and LFLX. In conclusion these data suggest that phototoxic potencies of the quinolones tested were; LFLX > ENX > CPFX $\geq$ LB20304a. No phototoxic dose of LB20304a in mice was 100 mg/kg.

• 미생물학회지
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• 제38권4호
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• pp.265-265
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• 2002

Iron increased the susceptibilities of clinical isolates Pseudomonas aeruginosa to quinolones. In the presence of iron, increased susceptibilities to ofloxacin were observed in twenty-six out of thirty isolates and with no change in four isolates. In the case of norfloxacin, iran increased susceptibilities of twelve isolates but did not render any change in eighteen isolates. In the case of ciprofloxacin, iron decreased the MICs (Minimal Inhibitory Concentration) of twenty isolates, increased the MIC of one isolate, and did net change the MICs of nine isolates. To find out how iron increased susceptibility to ofloxacin, bacterial cells were grown in Muller Hinton (MH) media and succinate minimal media (SMM) to induce iran acquisition systems and the intracellular ofloxacin concentrations were assayed in the presence of iron. The addition of iron to the media decreased the MICs of cells whether they were grown in MH or SMM. Siderophores, carbonyl cyanide m-chlorophenylhydrazone (an inhibiter of proton motive force), and ouabain (an inhibitor of ATPase) did not decrease the effect of iron. Results suggested that the increase in the intracellular ofloxacin concentration by iron is accomplished not by decreasing the efflux but by increasing the of ofloxacin permeability.

• Archives of Pharmacal Research
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• 제19권5호
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• pp.353-358
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• 1996

E. coli 11 and E. coli 101, clinical isolates of Escherichia coli were resistant to various quinolones, especially MICs to norfloxacin of both strains were higher than 100 mg/ml. In the presence of carbonyl cyanide m-chlorophenylhydrazone, a proton gradient uncoupler, norfloxacin uptake in both strains was increased, suggesting that an efflux system play an important role in the norfloxacin resistance. Outer membrane proteins of the susceptible and resistant strains which could affect the route of norfloxacin entry into cells were different. When quinolone resistance determining region(QRDR) of gyrA was amplified using PCR and cut with Hinf I, QRDR in the susceptible strain yielded two fragments while QRDRs in E. coli 11 and E. coli 101 yielded only one uncut fragment. When DNA sequence of QRDR was analyzed, there were two mutations as Ser-83 and Asp-87 in both resistant strains. these residues were changed to Leu-83 and Asn-87, respectively. These results showed that the norfloxacin resistance of E. coli 11 and E. coli 101 was resulted from multiple changes-an altered DNA gyrase A subunit, a change in route of drug entry, and reduction in quinolone concentration inside cells due to an efflux system.