• 한국환경농학회지
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• 제29권4호
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• pp.315-327
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• 2010

A vast increase of antibiotics usage in concentrated animal feeding operations (CAFOs) over the last few decades has led to an environmental risk due to the presence of antibiotic residuals in different environmental compartments. Especially in Korea, the use of antibiotics in CAFOs is much greater than in other developed countries. One of the primary adverse impacts of antibiotic residuals in the environment is that they readily produce antibiotic resistant bacteria (ARB), which exert detrimental effects on the ecosystem as well as human health. In this article, the impacts of veterinary antibiotic residuals with regard to their quantification and management, and desirable remediation technologies have been widely reviewed. This review article concluded that the continuous monitoring should be required to ensure the safety of antibiotic residuals in the surrounding environments. Furthermore, the management guidelines of antibiotic residuals need to be developed in the future.

• 한국동물위생학회지
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• 제37권1호
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• pp.35-43
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• 2014

Salmonellosis has caused heavy losses in swine industry and implications for public health. Recently, the urgent problem of antibiotic resistance due to multidrug-resistant Salmonella spp. has been on the rise. The use of host-specific bateriophages as a biocontrol is one possible alternative. In this study, clinical signs, growth performance, quantification and detection of antigen, histopathological changes of gastrointestinal tracts were analyzed comparatively in weaned piglets according to administration of bacteriophages and challenge with Salmonella (S.) Typhimurium. Piglets challenged with S. Typhimurium after administered with bacteriophages showed reduced clinical signs, higher growth performance, lower bacterial shedding, lower quantificational value of antigens in intestines, higher V/C ratio and higher the number of goblet cells in intestines than piglets administered without bacteriophage and challenged with S. Typhimurium. These results indicate that feeding contained with bacteriophages has effect to prevent infection of S. Typhimurium in weaned piglets and suggest that a use of bacteriophage can be considered a valid antibiotic alternative.

• 한국수산과학회지
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• 제42권1호
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• pp.15-19
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• 2009

A simple and sensitive method for erythromycin quantification by liquid chromatography electrospray mass spectrometry (LC-MS/MS) in fishery products was developed. Samples were extracted by liquid-liquid extraction using 70% acetonitrile. Lipids were removed by acetonitrile saturated hexane. LC separation was performed on a Shiseido UG C-18 column ($150\;mm{\times}2.0\;mm$ internal diameter.) with a gradient system of 0.2% acetic acid-acetonitrile containing 0.2% acetic acid as a mobile phase at flow rate of 0.2 mL/min. The mass spectrometer was operated in selected reaction monitoring with positive electro-spray interface. Transitions were monitored a m/z $734{\to}577$ and $734{\to}158$, with m/z $734{\to}577$ chosen for quantification. Recovery of erythromycin from fish and shrimp fortified at the 10 ng/mL, 50 ng/mL and 100 ng/mL were 91.6-109.4%, 84.4-111.2% and 98.8-109.6% with high precision, respectively. Limits of quantification and limits of detection of erythromycin in both fish and shrimp were 10.0 ng/mL and 1.0 ng/mL, respectively. This analysis method for erythromycin has been proposed for registration in the Korean Official Methods of Food Analysis and has been utilized for fishery products analysis by the Korea Food and Drug Adminstration and the National Fisheries Products Quality Inspection Service.

• 대한수의학회지
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• 제56권4호
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• pp.233-239
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• 2016

This study was conducted to analyze penicillin G (PEG), streptomycin (STR) and neomycin (NEO) residues in milk of healthy lactating cows. Milk samples were collected from all four quarters of 12 dairy cows 2−7 days after intramammary infusions of an ointment containing PEG, STR and NEO once (n = 4; group I) or twice (n = 4, group II) daily. Ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry was used to determine the antibiotic residues in the samples. The correlation coefficient ($r^2$) of the calibration curves for all antibiotics was > 0.999 and the limits of detection and quantification were $0.002-0.005{\mu}g/mL$ and $0.007-0.02{\mu}g/mL$, respectively. Recovery rates were ranged from 75.5 to 92.3%. In group I, PEG, STR and NEO residues were detected in milk at 2, 3 and 2 days post-treatment, respectively, which were below the maximum residue limit (MRL). In group II, PEG, STR and NEO residues were detected in milk at 2, 3 and 3 days post-treatment, respectively, which were bellow the MRL. These results suggest that a 3-day for milk withdrawal period after the ointment treatment might be sufficient for reduction of the antibiotic residues below the MRL.

• 한국식품과학회지
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• 제54권2호
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• pp.241-246
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• 2022

본 연구는 S. aureus에 대한 tuberostemonine의 항균 및 항생물막 효과에 대하여 확인하였다. S. aureus에 대한 tuberostemonine의 생장 저해 효과가 없음을 확인하였으나, crystal violet 염색법과 CLSM 이미지 측정을 통해 tuberostemonine이 유의한 S. aureus 항생물막 효과 가지는 것을 알 수 있었다. S. aureus의 생물막 형성과 분해 관련 유전자인 icaA와 agrA의 발현은 tuberostemonine를 처리하였을 때 유의미하게 각각 감소 또는 증가하는 것으로 나타났다. 따라서 본 연구에서 생물막 형성 저해 및 분해 효과가 확인된 천연화합물인 tuberostemonine은 S. aureus의 내성 발생 위험이 적은 새로운 항생물막제제로서 사용가능 할 것으로 사료된다.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.367-373
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• 2021

The antimicrobial resistance of Staphylococcus spp. and Gram negative strains present in air samples from waste sorting facilities was assessed. Phenotypic studies have revealed a high percentage of strains of Staphylococcus spp. resistant to methicillin. Genotypically and by RT-PCR, it was found that the mecA gene usually associated with methicillin resistance was present in 8% of the Staphylococcus strains isolated. About 30% of the Gram negative strains from the same samples also displayed resistance to meropenem and 79% of these were resistant to multiple antibiotics from different classes, namely cephalosporins and β-lactams. The results suggest that in professional activities with high levels of exposure to biological agents, the quantification and identification of the microbial flora in the work environment, with the determination of the presence of potential agents displaying multi-resistances is of relevance to the risk assessment. The personal protection of workers is particularly important relevance in these cases, since many of the strains that exhibit multi-resistance are potential opportunistic agents.

• 농업과학연구
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• 제49권4호
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• pp.795-807
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• 2022

The development and commercialization of industrial genetically modified (GM) organisms is actively progressing worldwide, highlighting an increased need for improved safety management protocols. We sought to establish an environmental monitoring method, using real-time polymerase chain reaction (PCR) and propidium monoazide (PMA) treatment to develop a quantitative detection protocol for living GM microorganisms. We developed a duplex TaqMan quantitative PCR (qPCR) assay to simultaneously detect the selectable antibiotic gene, ampicillin (AmpR), and the single-copy Escherichia coli taxon-specific gene, D-1-deoxyxylulose 5-phosphate synthase (dxs), using a direct cell suspension culture. We identified viable engineered E. coli cells by performing qPCR on PMA-treated cells. The theoretical cell density (true copy numbers) calculated from mean quantification cycle (Cq) values of PMA-qPCR showed a bias of 7.71% from the colony-forming unit (CFU), which was within ±25% of the acceptance criteria of the European Network of GMO Laboratories (ENGL). PMA-qPCR to detect AmpR and dxs was highly sensitive and was able to detect target genes from a 10,000-fold (10^-4) diluted cell suspension, with a limit of detection at 95% confidence (LOD_95%) of 134 viable E. coli cells. Compared to DNA-based qPCR methods, the cell suspension direct PMA-qPCR analysis provides reliable results and is a quick and accurate method to monitor living GM E. coli cells that can potentially be released into the environment.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.258-265
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• 2023

축산용 항생제는 투여된 양의 일부만이 체내에서 사용되며 나머지는 모화합물 형태나 대사체로서 분뇨를 통하여 배출된다. 이러한 분뇨는 자원화 시설로부터 퇴액비로 생산되어 농경지에 살포됨으로써 농업환경에 유입되어 2차 오염 등을 초래하고 있다. 본 연구는 국내 가축분뇨 자원화 시설의 액비 생산단계별로 6종 축산용 항생제의 잔류 농도를 비교하고 액비 성분 질소 함량과의 상관성을 평가하기 위해 수행되었다. Buffer 및 SPE를 사용한 전처리 방법은 ppb 수준에서 63.4-106.7%의 회수율을 나타냈으며, 정량한계의 범위는 0.009-0.037 ㎍/L이었다. 공동자원화 시설 생산 액비의 생산단계별 잔류 항생제 농도와 규격함량 N 성분 함량과의 상관성 평가를 분석한 결과 액비화 과정 중 부숙 기간이 경과함에 따라 N 성분 및 항생제 잔류 농도가 감소하는 경향을 보여 주었다. 액비 원료, 중기 및 제품 중 SMZ의 평균 잔류 항생제는 40.85, 26.17, 3.54 ㎍/L이었으며 CTC의 경우 2.32에서 1.25 ㎍/L 수준으로 감소하였다. 다른 4종 항생제 역시 생산단계별로 잔류 농도가 감소하는 경향을 보여주었으며 액비 규격성분 N은 생산단계별 함량이 0.21에서 0.096%로 감소하였다. 액비 생산단계별 잔류 항생제 농도와 규격 성분 N 함량과의 상관성 평가는 항생제 저감화 지표 설정의 기초자료로 활용 가능할 것으로 판단된다.

• 한국물환경학회지
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• 제32권6호
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• pp.670-699
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• 2016

In this study, 16 antibiotics were selected from among the top 30 veterinary antibiotics sold in South Korea in 2014, as well as from among the pharmaceuticals targeted by EPA method 1694, in order to review analytical methods for the detection of trace levels of antibiotics in environmental samples: surface water, soils, animal origin foods, and manures. LC-MS/MS was heavily used. In the chromatography for the detection of the selected antibiotics, the $C_{18}$ column was mostly used at the temperature of $30{\sim}40^{\circ}C$. Water and methanol/acetonitrile were commonly chosen as a nonpolar and a polar mobile phase, respectively. Gradient elution was applied to separate multiclass antibiotics. Volatile additives, such as formic acid, acetic acid, and ammonium acetate were mixed with the mobile phase to improve the ionization efficiency of analytes and the sensitivity in MS detection. Electrospray ionization (ESI) was widely used in the LC-MS/MS and positive ionization was preferred to determine the selected antibiotics. A protonated $[M+H]^+$ molecule was selected as a precursor ion, and its two transitions were analyzed, one for quantitative measurement and the other for confirmation. This study reviewed linearity of the calibration curve, recovery, repeatability, method detection limits (MDLs), and method quantification limits (MQLs) for each target compound used to validate the developed analytical methods.

• 한국물환경학회지
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• 제32권6호
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• pp.649-669
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• 2016

This study explored the analytical conditions for 21 veterinary antibiotics which have been popularly sold in South Korea in 2014 but have not yet been targeted in EPA method 1694. Most of the selected antibiotics were separated by a reverse-phase C18 column with a combination of (buffered) water and organic polar solvent, which was commonly methanol and acetonitrile in the gradient elution mode. Volatile additives such as formic acid, ammonium acetate and ammonium formate were usually added to the mobile phases to minimize asymmetrical and tailing of antibiotics' peaks and to increase their ionization in mass spectrometry. The analytical methods of aminoglycoside antibiotics were distinct from those of the other antibiotics in terms of adoption of ion-pair chromatography (IPC) and hydrophilic interaction liquid chromatography (HILIC) capable of retaining and separating extremely polar compounds due to their hydrophilicity. Trifluoroacetic acid or heptafluorobutyric acid was frequently added to the mobile phase as an ion-pair reagent for the IPC. Tandem mass spectrometry was numerously applied to the detection of antibiotics using positive electrospray ionization (ESI) and the selected reaction monitoring (SRM) mode. All reviewed analytical methods had been/were validated by evaluating recovery, limits of detection and quantification, decision limit or detection capability of the methods.