• 식물병연구
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• 제21권4호
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• pp.255-260
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• 2015

We investigated influence of three commercial antibiotics viz., oxolinic acid, streptomycin, and validamycin A, on biocontrol and plant growth promoting activities of Bacillus vallismortis EXTN-1 and BS07M in Chinese cabbage. Plants were pre-drenched with these strains followed by antibiotics application at recommended and ten-fold diluted concentration to test the effect on biocontrol ability against soft rot caused by Pectobacterium carotovorum SCC1. The viability of the two biocontrol strains and bacterial pathogen SCC1 was significantly reduced by oxolinic acid and streptomycin in vitro assay, but not by validamycin A. In plant trials, strains EXTN-1 and BS07M controlled soft rot in Chinese cabbage, and there was a significant difference in disease severity when the antibiotics were applied to the plants drenched with the two biocontrol agents. Additional foliar applications of oxolinic acid and streptomycin reduced the disease irrespective of pre-drench treatment of the PGPRs. However, when the plants were pre-drenched with EXTN-1 followed by spray of validamycin A at recommended concentration, soft rot significantly reduced compared to untreated control. Similarly, strains EXTN-1 and BS07M significantly enhanced plant growth, but it did not show synergistic effect with additional spray of antibiotics. Populations of the EXTN-1 or BS07M in the rhizosphere of plants sprayed with antibiotics were significantly affected as compared to control. Taken together, our results suggest that the three antibiotics used for soft rot control in Chinese cabbage could affect bacterial mediated biocontrol and plant growth promoting activities. Therefore, combined treatment of the PGPRs and the commercial antibiotics should be carefully applied to sustain environmental friendly disease management.

• 한국토양비료학회지
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• 제51권1호
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• pp.8-15
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• 2018

A portion of the veterinary antibiotics administrated to livestock are generally excreted via feces and urine. Tetracyclines and tylosin have a greater priority of environmental risk in Korea based on the consumption and the potential to reach soil and water environment. The antibiotics in animal byproducts need to be reduced or eliminated before they are applied to agricultural lands through composting or other agricultural practices. The objective of the study was to investigate the effect of aeration on degradation of antibiotics during storage of swine slurry. Two antibiotics, tetracycline (TC) and tylosin (TYL), were detected from the swine slurry used in the study. One hour aeration per day for 62 days reduced TC concentration from 199 to $43ng\;L^{-1}$ compared with $104ng\;L^{-1}$ without aeration. Aeration for three and six hours decreased TC level to 30 and $23ng\;L^{-1}$, respectively. The dissipation of TC was fitted with a first-order kinetic model. Aeration for 1, 3, and 6 hours every day increased the first-order rate constant, k, from $0.011day^{-1}$ under anaerobic condition to 0.022, 0.026, and $0.037day^{-1}$, respectively. For TYL, aeration during storage of swine slurry enhanced k from $0.0074day^{-1}$ to 0.014, 0.018, and $0.031day^{-1}$ for 1, 3, and 6 hours per day, respectively. For liquid swine slurry, biotic processes can be more effective for dissipation of antibiotics than abiotic processes because of low organic matter and high water content. These results suggest that aeration can increase the degradation rate of antibiotics during storage of swine slurry.

• Journal of Animal Science and Technology
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• 제66권1호
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• pp.57-78
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• 2024

In a global context, bacterial diseases caused by pathogenic bacteria have inflicted sustained damage on both humans and animals. Although antibiotics initially appeared to offer an easy treatment for most bacterial infections, the recent rise of multidrug-resistant bacteria, stemming from antibiotic misuse, has prompted regulatory measures to control antibiotic usage. Consequently, various alternatives to antibiotics are being explored, with a particular focus on bacteriophage (phage) therapy for treating bacterial diseases in animals. Animals are broadly categorized into livestock, closely associated with human dietary habits, and companion animals, which have attracted increasing attention. This study highlights phage therapy cases targeting prominent bacterial strains in various animals. In recent years, research on bacteriophages has gained considerable attention, suggesting a promising avenue for developing alternative substances to antibiotics, particularly crucial for addressing challenging bacterial diseases in the future.

• 한국환경농학회지
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• 제42권1호
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• pp.8-13
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• 2023

Biodegradation of antibiotics in soil can be affected by various environmental factors. This study was set to investigate the effect of environmental conditions such as soil pH and temperature on the degradation of oxolinic acid (OA), one of the agricultural antibiotics used in South Korea, in soil. Rice paddy soil (RS) and field soil (FS) were contaminated with OA and the soil pH was adjusted to 5.7±0.2, 6.8±0.2, and 7.6±0.1. The soil samples were kept at different temperatures (2.3±0.2, 23.0±0.6, 30.5± 0.3℃) for 30 d. The changes in the OA concentrations were determined at selected times. With the RS and FS, the OA removal was not affected by the soil pH used in this study; however, at pH 7.6, the OA removal in the RS was greater than that in the FS, which can be attributed to the different soil properties. The OA removal was similar at 23.0 and 30.5℃ in both soils, but was lower at 2.3℃. The information on the effect of different environmental conditions on the degradation of antibiotics in soil is very limited. Therefore, further studies are needed to better manage the residual antibiotics in the agricultural environment.

• 한국토양비료학회지
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• 제40권1호
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• pp.43-50
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• 2007

가축 질병의 예방 및 치료뿐만 아니라 사료 이용효율 증대와 생장 촉진을 위하여 축산용 항생제가 쓰여져 왔으며, 이 항생제는 가축분뇨를 통해 배출되어 농경지에 유입될 가능성이 있다. 나아가 용탈과 표면 유거를 거쳐 수계에 도달할 수 있으나, 모든 항생제의 환경 유출 가능성을 검토하는 데에는 많은 시간과 노동력, 예산이 필요하다. 본 연구는 축산용 항생제의 사용량과 잠재적 환경 유출 가능성을 기준으로 우선 순위를 결정하고자 수행되었다. 2004년에 우리 나라에서 판매된 항생제는 83종으로 약 1,400 톤에 달하였으며, 이 가운데 25 톤 이상 사용된 항생제는 10종이었다. 3 톤 이상 쓰인 36 종의 항생제를 대상으로, 가축의 배출율과 토양 흡착 정도를 가지고 잠재적 환경 유출 가능성을 판단하여 17 종을 선발하였다. 축산용 항생제의 사용량과 잠재적 환경 유출 가능성을 종합하여 검토한 결과, amoxicillin과 carbadox, chlortetracycline, neomycin, oxytetracycline, sulfamethazine, sulfathiazole, tylosin 등 8종이 상대적으로 환경으로의 유출 가능성이 높아 금후 정밀한 평가가 요구되었다. 비록 항생제의 가축분뇨로의 배출율과 토양내 동태에 대한 정보가 제한적일지라도, 본 연구에서는 한국에서 쓰이고 있는 축산용 항생제의 사용량과 알려진 항생제의 배출율과 토양 흡착 정도를 바탕으로 환경으로의 유출 가능성이 큰 항생제를 결정하였다.

• Journal of Applied Biological Chemistry
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• 제64권2호
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• pp.177-184
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• 2021

축산용 항생제는 투여된 양의 일부만이 체내에서 사용되며 나머지는 분뇨로 배출되며 이를 활용한 퇴비를 농경지에 살포함으로써 농업환경에 유입되어 2차 오염 등을 초래하고 있다. 따라서, 농업환경 중 항생제 관리기준 설정 등 사후 관리 기술이 필요하다. 본 연구는 국내 사용빈도가 높은 것으로 알려진 tetracycline 및 sulfonamide 계열 등의 항생제를 대상으로 매체별 잔류량을 비교하고 퇴비 시용 전·후 농경지 토양 중 잔류항생제의 위해성을 평가하기 위하여 수행되었다. Buffer 및 SPE를 사용한 전처리 방법은 ppb 수준에서 70% 이상의 회수율을 나타냈으며, 검출한계(LOD)의 범위는 퇴비와 토양에서 각각 0.13-0.46 ㎍/kg과 0.05-0.25 ㎍/kg이었다. 잔류 항생제 분석결과 퇴비 중 tetracycline 계열 항생제의 잔류 농도는 5.38-196.0 ㎍/kg, sulfonamide 계열은 below the detection of limit (BDL)-259.0 ㎍/kg 수준으로 검출되었다. 농경지 토양의 경우 각각 0.30-53.3 ㎍/kg, BDL-4.16 ㎍/kg의 잔류 수준을 나타냈으며 토양분배계수(Kd) 값이 높은 tetracycline 계열 항생제의 잔류 농도가 sulfonamide 계열보다 높았다. 퇴비 시용 전후의 농경지 토양의 항생제에 대한 인체위해도는 항생제 종류에 따른 차이가 있었으나, 전체 HQ가 1 이하에서 안전하다는 기준에 의하면 조사된 항생제 5종 모두 인체 위해성이 매우 낮았으며 시용 전·후의 영향이 전체 위해도에 미치는 비율을 고려하면, 퇴비시용이 토양의 항생제에 대한 인체위해성에 미치는 영향은 미비한 것으로 판단되었다.

• 한국환경과학회지
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• 제28권11호
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• pp.983-991
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• 2019

This study investigated the use of a hydroxyl-radicals-generated microbubble/catalyst (MB/Cat) system for removing organic pollutants, nitrogen, and phosphorous from liquid fertilizer produced by livestock wastewater treatment. Use of the MB/Cat system aims to improve the quality of liquid fertilizer by removing pollutants originally found in the wastewater. In addition, a reduction effect has been reported for antibiotics classified as representative non-biodegradable matter. Samples of liquid fertilizer produced by an aerobic biological reactor for swine wastewater treatment were first analyzed for initial concentrations of pollutants and antibiotics. When the MB/Cat system was applied to the liquid fertilizer, TCOD, TOC, $BOD_5$, and $NH_3-N$, and $PO_4-P$ removal efficiencies were found to be approximately 52%, 51%, 30%, 21%, and 66%, respectively. Additionally, Amoxicillin hydrate was removed by 10%, and Chlortetracycline HCl and Florfenicol were not present at detectable levels These findings confirm that the MB/Cat system can be used with livestock wastewater treatment to improve liquid fertilizer quality and to process wastewater that is safe for agricultural re-use.

• 한국토양비료학회지
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• 제51권1호
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• pp.1-7
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• 2018

The veterinary antibiotics treated to livestock have a potential risk to reach to soil and water environment, and eventually be taken up by plants. The objective of the study was to investigate the effect of zeolite and shell meal fertilizer amendment on antibiotic uptake by plant when veterinary antibiotics in chicken manure compost were applied to agricultural land. Model antibiotics used in the study were chlortetracycline (CTC), tylosin (TYL), and sulfamethazine (SMT). Chlortetracycline level in lettuce was decreased to less than $0.08ug\;kg^{-1}$ by application of zeolite as compared with about $0.26ug\;kg^{-1}$ for control without amendment on 33 days after transplanting. Tylosin was not detected for all the treatment. Sulfamethazine levels in lettuce ranged from 11 to $19{\mu}g\;kg^{-1}$ on a fresh weight basis and gradually decreased with time. Zeolite application decreased the SMT levels in lettuce by greater extent than shell meal fertilizer amendments. Results from the 61-d greenhouse experiment imply that application of zeolite at a rate of $1.5Mg\;ha^{-1}$ or shell meal fertilizer at a rate of $2.0Mg\;ha^{-1}$ can reduce CTC and SMT concentration in lettuce cultivated in soil fertilized with antibiotic-contaminated chicken manure compost.

• Journal of Microbiology and Biotechnology
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• 제5권6호
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• pp.324-334
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• 1995

The actinomycete strain A 11 was antagonistic to plant pathogenic fungi Phytophthora capsid and Magnaporthe grisea. Based on the diaminopimelic acid (DAP) type and morphological characteristics examined by scanning electron microscopy, the strain A 11 was confirmed to belong to the genus Streptomyces. Based on Willcox probability and similarity level, the strain A 11 was numerically identified as Streptomyces flaveus using TAXON program of Ward and Goodfellow. Antibiotic production of S. flaveus strain A 11 was most favorable when cultured on glycerol yeast extract peptone (GYP) agar for 20 days at $28^{\circ}C$. The crude antibiotics from solid GYP agar cultures of the strain A 11 were most effective against Phytophthora capsici and Sclerotinia sclerotiorum among the fungi tested. Antifungal activity of the antibiotics against Alternaria solani, Botryosphaeria dothidea, Cercospora capsici, Magnaporthe grisea, and Rhizoctonia solani was somewhat high, whereas Colletotrichum gloeosporioides and Fusarium oxysporum f. sp. cucumerinum were rarely inhibited even at high concentrations.

• Asian-Australasian Journal of Animal Sciences
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• 제24권5호
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• pp.643-649
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• 2011

The objective of this study was to determine the effect of feeding direct-fed microbials (DFM) on the growth performance and prophylaxis of calf diarrhea during the pre-weaning period as an alternative to antibiotics. A multi-species DFM was formulated including three lactic acid bacteria (Lactobacillus salivarius Ls29, Pediococcus acidilactia Pa175, and L. plantarum Lp177), three Bacillus strains (B. subtilis T4, B. polymyxa T1 and SM2), one yeast, Saccharomyces boulardii, and a nonpathogenic E. coli Nissle 1917. Lactic acid bacteria and Bacillus strains were selected based on the antibacterial activity against various animal pathogens, especially pathogenic E. coli using agar diffusion methods in vitro. Test and control groups were fed milk replacer and calf starter supplemented with DFM ($10^9$ cfu each of eight species/d/head, n = 29) or with antibiotics (0.1% neomycin sulfate in milk replacer and Colistin 0.08% and Oxyneo 110/110 0.1% in calf starter, n = 15), respectively. Overall fecal score and the incidence rate of diarrhea were reduced in the DFM group compared to the antibiotics one. About 40% of calves in antibiotic group suffered from diarrhea while in DFM group only 14% showed diarrhea. There was no difference in the average daily gain and feed efficiency of two groups. The hematological levels of calves were all within the normal range with no significant difference. In conclusion, the feeding of multispecies DFM during the pre-weaning period could reduce calf diarrhea and there was no difference in the growth performance between the groups, thus showing the potential as an alternative to antibiotics.