• Journal of Microbiology and Biotechnology
• /
• 제28권12호
• /
• pp.2064-2070
• /
• 2018

Pseudomonas tolaasii 6264 is a representative strain that causes bacterial blotch disease on the cultivated oyster mushroom, Pleurotus ostreatus. Bacteriophages are able to sterilize the pathogenic P. tolaasii strains, and therefore, they can be applied in creating disease-free mushroom cultivation farms, through a method known as "phage therapy". For successful phage therapy, the characterization of phage-resistant strains is necessary, since they are frequently induced from the original pathogenic bacteria in the presence of phages. When 10 different phages were incubated with P. tolaasii 6264, their corresponding phage-resistant strains were obtained. In this study, changes in pathogenic, genetic, and biochemical characteristics as well as the acquired phage resistance of these strains were investigated. In the phylogenetic analyses, all phage-resistant strains were identical to the original parent strain based on the sequence comparison of 16S rRNA genes. When various phage-resistant strains were examined by three different methods, pitting test, white line test, and hemolytic activity, they were divided into three groups: strains showing all positive results in three tests, two positive in the first two tests, and all negative. Nevertheless, all phage-resistant strains showed that their pathogenic activities were reduced or completely lost.

• Journal of Dairy Science and Biotechnology
• /
• 제39권1호
• /
• pp.1-8
• /
• 2021

The surroundings of livestock farms, including dairy farms, are known to be a major source of development and transmission of antibiotic-resistant bacteria. To control antibioticresistant bacteria in the livestock breeding environment, farms have installed livestock wastewater treatment facilities to treat wastewater before discharging the final effluent in nearby rivers or streams. These facilities have been known to serve as hotspots for inter-bacterial antibiotic-resistance gene transfer and extensively antibiotic-resistant bacteria, owing to the accumulation of various antibiotic-resistant bacteria from the livestock breeding environment. This review discusses antibiotic usage in livestock farming, including dairy farms, livestock wastewater treatment plants as hotspots for antibiotic resistant bacteria, and nonenteric gram-negative bacteria from wastewater treatment plants, and previous findings in literature.

• 한국작물학회지
• /
• 제50권3호
• /
• pp.151-155
• /
• 2005

1970년대 이후 육성된 우리나라 벼품종들에 대하여 벼흰잎마름병 레이스 K1, K2, K3 및 K3a에 대한 반응을 검토한 결과를 요약하면 다음과 같다. 1. 통일형인 51품종의 저항성 정도를 검정한 결과, 레이스 K1에 저항성 13품종, 레이스 K1과 K2에 저항성 9품종, 레이스 K1, K2, 및 K3에 저항성 1품종, 레이스 K1, K2, K3 및 K3a모두에 저항성을 보인 것은 14품종이었다. 2. 자포니카형인 158품종의 저항성 반응을 살펴 본 결과, 레이스 K1 저항성 31품종, 레이스 K1과 K2에 저항성 1품종, 레이스 K1, K2 및 K3에 저항성 28품종, 레이스 K1, K2, K3 및 K3a모두에 저항성 1품종이었다. 3. 레이스 K1, K2, K3 및 K3a에 저항성인 품종은 통일형 품종이 자포니카형 품종 보다 훨씬 많았다.

• 한국육종학회지
• /
• 제43권4호
• /
• pp.282-287
• /
• 2011

본 연구는 최근 콩 재배에서 심각한 병으로 대두된 콩 불마름병에 대한 저항성 유전자인 rxp 근접분자표지를 개발하고자 수행하였다. 콩 불마름병은 국내에서 전국적으로 발생하는 심각한 세균병으로 이에 관련하여 세균병 접종을 이용한 저항성 품종과 감수성 품종에 대한 연구가 많이 진행되고 있지만 정확한 유전자의 염기서열이 밝혀져 있지 않고 있다. 본 연구는 콩 불마름병에 저항성 품종 8개체와 감수성 품종 8개체를 이용하여 rxp 유전자 근접분자표지를 확인하기 위하여 수행하였다. 콩 불마름병 저항성 유전자로 알려진 rxp 유전자는 chromosome 17의 Satt486과 Satt372 사이에 있다고 알려져 있으며, 최근 연구결과로 chromosome 17의 7.27-7.30 Mbp 사이에 있다. 연구진은 chromosome 17의 6.6-7.3 Mbp 사이에 random으로 분자표지를 제작하여 저항성과 감수성 품종에서 다형성을 알아보았다. 실험결과로 콩 불마름병관련 근접분자표지 3점을 개발하였고, Rxp17-700 분자표지는 흥미로운 rxp 근접분자표지 임을 확인하였다. 이러한 콩 불마름병 저항성관련 근접분자표지는 앞으로 저항성 품종을 선발하는데 도움이 될 것이다.

• 대한임상검사과학회지
• /
• 제54권1호
• /
• pp.23-27
• /
• 2022

제주특별자치도에 위치한 대중음식점에서 제공하는 일회용 물티슈를 대상으로 식품의약품안전처장이 정하는 표시사항을 준수하는지 여부와 세균의 오염도를 평가하였다. 일회용 물티슈 32종류 중 5 종류의 일회용 물티슈는 영업소의 명칭 및 소재지가 표기되어 있지 않았다. 제조연월일과 유통기한은 12 종류의 물티슈만 표시 되어있었다. 일회용 물티슈 32종류 중 9종류의 물티슈에서 세균 집락이 배양되었으며, 23종류(71.9%)의 물티슈에서는 세균이 배양되지 않았다. 세균을 동정한 결과 그람양성알균은 Staphylococcus haemolyticus 4균주, Staphylococcus hominis 1균주, Staphylococcus warneri 3균주, 그람음성막대균은 Pseudomonas fluorescens 1균주로 동정되었다. 동정된 그람양성알균 8균주에 대한 항균제감수성검사를 시행한 결과 oxacillin, vancomycin 감수성으로 MRCNS(methicillin resistant coagulase-negative Staphylococci)는 발견되지 않았으며, 동정된 그람음성막대균 1균주에 대한 항균제감수성검사 결과는 imipenem, meropenem에 모두 감수성으로 다약제내성균은 아니었다. 본 연구를 통해 위생용품으로 지정된 일회용 물티슈 개별 포장지 겉면에 반드시 제조년월일과 유통기한을 표기하고, 보관기준을 준수하여 오염되지 않은 깨끗한 물티슈를 사용해야 한다고 사료된다. 또한 위생관리 감독 강화와 개선방안 및 개인 위생관리 및 국민보건 수준향상에 기여하고자 한다.

• 식물병과 농업
• /
• 제5권2호
• /
• pp.95-99
• /
• 1999

Chemical control of bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae was attempted by spraying of streptomycin sulfate ·oxytetracycline WP streptomycin WP streptomycin ·copper hydroxide WP kasugamycin SL kasugamycin·copper oxychloride WP and copper hydroxide WP. The control efficacies of the bactericides were variable depending upon the spraying schedule,. Application of streptomycin WP and streptomycin sulfate·oxytetracycline WP from middle April to early May was found to be the most effective in controlling the bacterial canker. For copper hydroxide WP the spraying from middle January to early February showed the highest control efficacy. Kasugamycin SL was the most effective in controlling the disease by spraying from middle April to early May but it was still relatibvely effective during other spray periods. Foliar application of copper hydroxide WP and copper-antibiotic formulaions after middle April caused severe phytotoxicity. Kasgamycil SL streptomycin WP streptomycin·copper hydroxide WP and copper hydroxide WP were potential bactericides which could substitute streptomycin sulfate·oxytetracycline WP. Selective applications of the bactericides according to their optimum spray time can enhance the control efficacies against bacterial canker of kiwifruit and retard the emergency of resistant strains of P. syringae pv. actinidiae to the bactericides. The optimum spray number of streptomycin sulfate·oxytetracycline WP was 3 times with 15-day-intervals or 4 times with 10-day-intervals. The result suggested that the potential bactericides to bacterial canker of kiwifruit should be also used according to their optimum spray schedules in order to get their highest control efficacies.

• Membrane and Water Treatment
• /
• 제10권6호
• /
• pp.395-404
• /
• 2019

The influence of chlorine on marine bacterial communities was examined in this study. A non-chlorine-adapted marine bacterial community (NCAM) and a chlorine-adapted bacterial community (CAM, bacterial community treated with $0.2mg-Cl_2/L$ chlorine) were cultivated for 1 month. A distinct difference was observed between the NCAM and CAM, which shared only eight operational taxonomic units (OTUs), corresponding to 13.1% of the total number of identified OTUs. This result suggested that chlorine was responsible for the changes in the marine bacterial communities. Kordiimonas aquimaris was found to be a chlorine-resistant marine bacterium. The effect of intermittent chlorination on the two marine biofilm communities formed on the reverse osmosis (RO) membrane surface was investigated using various chlorine concentrations (0, 0.2, 0.4, 0.6 and 0.8 mg $Cl_2/L$). Although the average number of adherent marine bacteria on the RO membrane over a period of 7 weeks decreased with increasing chlorine concentration, disinfection efficiencies showed substantial fluctuations throughout the experiment. This is due to chlorine depletion that occurs during intermittent chlorination. These results suggest that intermittent chlorination is not an effective disinfection strategy to control biofilm formation.

• Archives of Pharmacal Research
• /
• 제28권6호
• /
• pp.660-666
• /
• 2005

The intestinal microbiota are important to the host with regard to resistance they impart against bacterial infections and their involvement in mediating metabolic functions. Lactic acid producing bacteria such as Lactobacillus play an important physiological role in these matters. The aim of the present study was to isolate Lactobacillus sp. that inhibits enteric pathogens. Initially, 17 isolates from healthy Koreans were collected on Lactobacillus selective medium. Resistance of the isolates to antibiotics including rifampicin, streptomycin, clindamycin and vancomycin was measured. One of the isolate was identified as Lactobacillus ruminus on the basis of bacterial cell morphology, cultural characteristic and biochemical characteristics, 16S rRNA sequence analysis and PCR-RAPD. Antimicrobial activity of the bacterium against Vancomycin Intermediate Resistant Staphylococcus aureus (VISA) and Vancomycin-Resistant Enterococci (VRE) was measured. About $10^4$ cells of VISA or VRE were mixed with 1, 5, and 9 mL of L. ruminus SPM 0211 and the final volume was adjusted to 10 mL with brain heart infusion (BHI) broth. The cell suspension was incubated for 3, 6, 9, and 24 h, serially diluted and then plated on BHI agar plates. As numbers of L. ruminus SPM 0211 were increased, viable cell count of VISA and VRE decreased. The strongest antimicrobial activity of SPM 0211 was observed after 9 h incubation in any mixture, almost completely inhibiting the growth of these two bacteria. The results suggest that the freshly isolated L. ruminus SPM 0211 may be used as a pro-biotic microbe that prevents the colonization of enteric pathogens and can thereby promote good gastrointestinal health.

• 식물병연구
• /
• 제13권2호
• /
• pp.88-92
• /
• 2007

우리나라 참다래 과수원에서 참다래 꽃썩음병을 일으키는 원인 세균인 Pseudomonas syringae pv. syringae를 분리하였다. 총 41개 균주 중 스트렙토마이신 저항성을 보이는 2개의 균주를 대상으로 PCR과 염기서열 결정을 통해 저항성 유전자 구조를 조사하였다. PCR결과 스트렙토마이신 저항성유전자는 Tn5359a에 들어 있는 strA-strB 구조인 것으로 밝혀졌다. Xanthomonas campestris와 Erwinia amylovora에서 알려진 IS6100과 IS1133은 발견되지 않았다. strA-strB의 염기서열은 이미 밝혀진 Tn5393a와 동일하였다. 두 스트렙토마이신 저항성 균주는 각각 3개의 플라스미드를 가지고 있었으며 저항성 유전자는 그 중 100kb의 플라스미드에 들어 있었다.

• Journal of Microbiology and Biotechnology
• /
• 제26권2호
• /
• pp.408-420
• /
• 2016

This study proposes an alternative approach for the use of chitosan silver-based dressing for the control of foot infection with multidrug-resistant bacteria. Sixty-five bacterial isolates were isolated from 40 diabetic patients. Staphylococcus aureus (37%) and Pseudomonas aeruginosa (18.5%) were the predominant isolates in the ulcer samples. Ten antibiotics were in vitro tested against diabetic foot clinical bacterial isolates. The most resistant S. aureus and P. aeruginosa isolates were then selected for further study. Three chitosan sources were tested individually for chelating silver nanoparticles. Squilla chitosan silver nanoparticles (Sq. Cs-Ag⁰) showed the maximum activity against the resistant bacteria when mixed with amikacin that showed the maximum synergetic index. This, in turn, resulted in the reduction of the amikacin MIC value by 95%. For evaluation of the effectiveness of the prepared dressing using Artemia salina as the toxicity biomarker, the LC₅₀ was found to be 549.5, 18,000, and 10,000 μg/ml for amikacin, Sq. Cs-Ag⁰, and dressing matrix, respectively. Loading the formula onto chitosan hydrogel dressing showed promising antibacterial activities, with responsive healing properties for the wounds in normal rats of those diabetic rats (polymicrobial infection). It is quite interesting to note that no emergence of any side effect on either kidney or liver biomedical functions was noticed.