• 한국동물위생학회지
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• 제34권1호
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• pp.37-43
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• 2011

This study was conducted to investigate the prevalence and genotypes of extended-spectrum ${\beta}$-lactamase (ESBL) in 377 Escherichia coli isolated from healthy and sick animals. Two isolates (0.5%), each of which were isolated from diseased swine and chicken, respectively, were confirmed as ESBL producing isolates by double disk synergy test, and showed a multidrug resistant phenotype. Minimum inhibitory concentration of cefotaxime for the two ESBL producing isolates were 3~4 times higher than those of ceftazidime, respectively. By PCR and sequencing, one isolate from swine have both $bla_{CTX-15}$ and $bla_{TEM-1}$, and one isolate from chicken have $bla_{CTX-15}$ and $bla_{TEM-116}$. Also, these genes were transferred to E. coli J53 by conjugation. These two isolates showed unrelated pulsed-field gel electrophoresis. To our knowledge, this is the first time that $bla_{TEM-116}$ gene was identified in E. coli isolated from animals in Korea. These results suggest more prudent use of third- generation cephalosporins, and surveillance and monitoring for ESBL producing E. coli in both animals and their environments should be necessary.

• 한국미생물·생명공학회지
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• 제49권2호
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• pp.239-248
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• 2021

The emergence of multidrug-resistant Acinetobacter baumannii has partly increased treatment failure and patient mortality. Class D β-lactamases is an important mechanism of resistance to beta-lactam antibiotics in this species. This study aimed to investigate the relationship between the presence oxacillinase gene and genetic fingerprints of A. baumannii isolates from the intensive care unit of an Egyptian tertiary care hospital. One hundred and twenty A. baumannii clinical isolates were collected. Multiplex PCR was performed to detect genes encoding oxacillinases (OXA-23, OXA-24, OXA-51, OXA-58 and OXA-143). Molecular typing of all collected isolates was performed using random amplified polymorphic DNA (RAPD)-PCR assay. Out of 120 examined isolates, 92, 88 and 84% were resistant to ertapenem, imipenem and meropenem, respectively. The species-specific, commonly present OXA-51 gene was found in all isolates while OXA-23 showed a high prevalence of 88% of isolates. OXA-24 and OXA-143 genes were detected in 3% and 1% of isolates, respectively. No OXA-58 gene was detected. Five clusters consisting of 19 genotypes were detected using RAPD-PCR. Genotype A was the most prevalent, it was observed in 62% of the isolates followed by genotype B (12%). These results revealed that genotypes A and B are common in the hospital. Results also demonstrate that RAPD-PCR is a rapid and reliable method for studying the clonal similarity among A. baumannii isolated from different clinical specimens.

• 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.

• 한국융합학회논문지
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• 제6권5호
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• pp.77-84
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• 2015

본 연구는 항균제에 내성을 보이는 대장균의 특성을 알아보기 위해 설사환자에서 분리된 대장균에 대한 항균제 감수성 및 병원성 인자의 상관성을 분자융합적 기술을 통해 조사하였다. 분리한 대장균의 항균제 내성은 60주에서 ESBL(extendede spectrum ${\beta}$-lactamase) positive균주가 8주이고, negative균주는 52주였다. ESBL 양성 8주 중 2주는 병원성 유전자가 검출되지 않았으며, stb(3주), flich7(1주), flich7-eae(2주)로 나타났다. ESBL 음성 52주 중 26주는 병원성 유전자가 검출되지 않았고, stx1(3주), stb(10주), flich7 및 eae(각 2주), stx1-flich7(2주), stx1-stb(4주), flich7-stb(2주), flich7-stb-eae(1주)이었다. 결론적으로 항균제 내성이 증가하는 시대에 분자 융합적 관점에서 독력 유전자의 분포와 항균제 내성과의 관계는 적게 나타났으나, 향후 다양한 독력 유전자의 분석을 통한 융합기술연구가 이루어진다면 보다 정확한 병원성 인자를 추정할 수 있을 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권3호
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• pp.402-413
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• 2001

Food safety is a term broadly applied to food quality that may adversely affect human health. These include zoonotic diseases and acute and chronic effects of ingesting natural and human-made xenobiotics. There are two major areas of concern over the presence of residues of antibiotics in animal-derived foodstuffs with regard to human health. The first is allergic reactions. Some antibiotics, such as penicillins can evoke allergic reactions even though small amounts of them are ingested or exposed by parenteral routes. The second is development of antibiotic resistance in gut bacteria of human. Recently multi-resistant pneumococcal, glycopeptide-resistant enterococci and gram negative bacteria with extended-spectrum $\beta$-lactamases have spread all over the world, and are now a serious therapeutic problem in human. Although it is evident that drugs are required in the efficient production of meat, milk and eggs, their indiscriminate use should never be substituted for hygienic management of farm. Drug should be used only when they are required. In addition to veterinary drugs, environmental contaminants that were contaminated in feed, water and air can make residues in animal products. Mycotoxins, heavy metals, pesticides, herbicides and other chemicals derived from industries can be harmful both to animal and human health. Most of organic contaminants, such as dioxin, PCBs and DDT, and metals are persistent in environment and biological organisms and can be accumulated in fat and hard tissues. Some of them are suspected to have endocrine disrupting, carcinogenic, teratogenic, immunodepressive and nervous effects. The governmental agencies concerned make efforts to prevent residue problems; approval of drugs including withdrawal times of each preparation of drugs, establishment of tolerances, guidelines regarding drug use and sanitation enforcement of livestock products. National residue program is conducted to audit the status of the chemical residues in foods. Recently HACCP has been introduced to promote food safety from farm to table by reducing hazardous biological, chemical and physical factors. Animal Production Food Safety Program, Quality Assurance Programs, Food Animal Residue Avoidance Databank are para- or non-governmental activities ensuring food safety. This topic will cover classification and usage or sources of chemical residues, their adverse effects, and chemical residue status of some countries. Issues are expanded to residue detection methodologies, toxicological and pharmacokinetic backgrounds of MRL and withdrawal time establishments, and the importance of non-governmental activities with regard to reducing chemical residues in food.

• 한국임상수의학회지
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• 제29권3호
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• pp.233-236
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• 2012

Cefquinome은 제4세대 cephalosporin으로 동물전용의약품으로 개발되었으며, ${\beta}$-lactamases에 대해서 매우 안정하고, 그람 음성 세균 및 양성 세균에 대한 광범위한 살균력을 가지고 있다. 본 연구는 현재 시판중인 cefquinome 주사제를 이유 자돈에 2 mg/kg 용량으로 근육 주사한 후 약물동태학적 특성을 파악하여 두 제제의 생물학적 동등성을 평가하였다. Cefquinome의 혈중 농도는 액체크로마토그래프/질량분석기를 이용하여 분석하였으며, 생물학적 동등성을 판정하기 위한 약물동태학적 인자로는 혈중 최고 농도 ($C_{max}$)와 혈장 농도 곡선하 면적 ($AUC_{0{\rightarrow}{\infty}}$)을 사용하였다. 시험약과 대조약의 혈중 최고 농도는 $4.34{\pm}0.58{\mu}g/mL$과 $4.22{\pm}0.47{\mu}g/mL$로 각각 나타났으며, 혈장 농도 곡선 하 면적은 $10.43{\pm}1.96{\mu}g{\cdot}h/mL$과 $10.25{\pm}2.98{\mu}g{\cdot}h/mL$로 관찰되었다. 로그변환한 약물동태학적 인자의 평균비율의 90% 신뢰 구간은 $C_{max}$의 경우 0.941-1.115이었고, $AUC_{0{\rightarrow}{\infty}}$의 경우 0.927-1.172로서 생물학적 동등성 기준인 0.8-1.25를 모두 만족시켰다. 이상의 결과로 시판중인 두 cefquinome 제제는 생물학적으로 동등하다고 판단된다.

• The Korean Journal of Medicine
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• 제99권3호
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• pp.149-157
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• 2024

목적: 장내세균에서 3세대 cephalosporin 계열 항생제에 내성을 나타내는 주된 내성 기전은 extended spectrum β-lactamase(ESBL)를 생성하는 것이다. ESBL 생성 장내세균은 ESBL 생성균이라고 하더라도 piperacillin/tazobactam 감수성 균인 경우 piperacillin/tazobactam을 사용해 볼 수 있으며 후향적 연구에서 carbapenem 계열 항생제를 투여한 경우에 비해 열등하지 않은 치료 효과가 보고된 바 있다. 하지만 미국감염학회 2023년 지침에서는 ESBL 생성 그람음성균 감염에서 carbapenem 계열 항생제를 권고하고 piperacillin/tazobactam 감수성인 그람음성균이더라도 carbapenem 계열 항생제를 투여하도록 하고 있다. 하지만 carbapenem 내성 장내세균의 증가 등으로 비 carbapenem 계열의 항생제들의 사용 필요성에 대한 평가는 아직도 필요한 상황이다. 이에 제주대학교병원의 ESBL 생성 장내세균속 균혈증 환자들의 carbapenem과 비 carbapenem 계열 항생제의 치료 효과를 보고한다. 방법: 2021년 1월부터 12월까지 527명의 성인 장내세균속 균혈증 환자들 중에서 ESBL 생성 장내세균속 환자 152명을 대상으로 후향적 자료를 수집하고 3개월 이내 장내세균 감염이 있었던 환자들과 30일 후 추적 관찰을 하지 못한 환자들을 제외하고 분석하였다. 결과: 총 118명의 ESBL 생성 장내세균속 균혈증 환자들중에서 54명의 환자가 확정적 항생제로 비 carbapenem 계열 항생제로 치료하였고 64명의 환자가 carbapenem 계열 항생제로 치료하였다. Kaplan-Meier 생존 분석 방법으로 30일 치료 실패율과 사망률을 분석한 결과 30일 치료 실패율은 비 carbapenem군이 16.7%, carbapenem군이 18.8%로 양 군 간의 유의한 차이는 없었다(p = 0.65). 30일 사망률은 비 carbapenem 계열군이 14.8%, carbapenem 계열군이 17.2%로 양 군 간의 유의한 차이는 없었다(p = 0.63). 전체 환자들 중에서 치료 실패한 환자들을 다변량 로지스틱 회귀 분석한 결과에서 요로 감염 외 감염과 이전 30일 이내 항생제 사용력이 있는 경우 치료 실패의 위험인자로 확인되었다. 결론: ESBL 생성 장내세균속 균혈증 환자들은 국내에서 확정적 항생제로 비 carbapenem 계열의 항생제를 사용해 볼수 있으나 중증 환자들을 포함한 다기관, 전향적 후속 연구들이 필요하다.