• 한국연초학회지
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• 제28권2호
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• pp.158-161
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• 2006

Main tobacco diseases were surveyed on major flue-cured leaf tobacco fields throughout South Korea in 2006. Mosaic caused by potato virus Y and bacterial wilt caused by Ralstonia solanacearum were most severe during harvest season. During last ten years, the damage by tobacco mosaic virus was reduced but the incidence of bacterial wilt increased. These changes of the disease incidences coincide with release time of the tobacco cultivar resistant to the tobacco mosaic virus but susceptible to bacterial wilt pathogen. Wild fire(Pseudomonas syringae pv. tabaci strain ungulate) occurred severely at Kangwon province, though the symptom of wild fire with yellow halo was not observed.

• 한국환경성돌연변이발암원학회지
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• 제19권1호
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• pp.34-38
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• 1999

Fumonisin B1 is a secondary metabolite of Fusarium moniliforme, a contaminant of corn and corn product. Fumonisin B1 has been shown to be responsible for major toxicological effects of the fungus in rats, horses, and pigs. Fumonisin B1 induced λ DNA fragmentation, which was increased with incubation time, reducing agent NADPH and metal ion (Cu2+). The DNA damage was inhibited by dimethyl sulfoxide (DMSO) or mannitol as radical scavenger for free radicals. DNA fragmentation, induced by fumonisin B1 in the presence of 1 mM NADPH and 0.1 mM CuCl2, was inhibited by 100 mM DMSO. By the in vitro reaction of fumonisin B1 with supercoiled plasmid pBR322 DNA, plasmid DNA was relaxed, eventually linearized in the agarose gel electrphoresis. From rifampicin sensitive E. coli CSH138 in bacterial mutagenesis system, the rifampicin resistant E. coli mutants were obtained by fumonisin B1. These results suggest that fumonisin B1 may be a possible environmental mutagen in bacterial mutagen assay system.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권6호
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• pp.324-331
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• 2019

Objectives: This study investigated the types and antibiotic sensitivity of bacteria in odontogenic abscesses. Materials and Methods: Pus specimens from 1,772 patients were collected from affected areas during incision and drainage, and bacterial cultures and antibiotic sensitivity tests were performed. The number of antibiotic-resistant bacteria was analyzed relative to the total number of bacteria that were tested for antibiotic susceptibility. Results: Bacterial cultures from 1,772 patients showed a total of 2,489 bacterial species, 2,101 gram-positive and 388 gram-negative. For penicillin G susceptibility tests, 2 out of 31 Staphylococcus aureus strains tested showed sensitivity and 29 showed resistance. For ampicillin susceptibility tests, all 11 S. aureus strains tested showed resistance. In ampicillin susceptibility tests, 46 out of 50 Klebsiella pneumoniae subsp. pneumoniae strains tested showed resistance. Conclusion: When treating odontogenic maxillofacial abscesses, it is appropriate to use antibiotics other than penicillin G and ampicillin as the first-line treatment.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.1-7
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• 2021

Bacterial biofilm is a community of bacteria that are embedded and structured in a self-secreted extracellular matrix. An important clinical-related characteristic of bacterial biofilms is that they are much more resistant to antimicrobial agents than the planktonic cells (up to 1,000 times), which is one of the main causes of antibiotic resistance in clinics. Therefore, infections caused by biofilms are notoriously difficult to eradicate, such as lung infection caused by Pseudomonas aeruginosa in cystic fibrosis patients. Understanding the resistance mechanisms of biofilms will provide direct insights into how we overcome such resistance. In this review, we summarize the characteristics of biofilms and chronic infections associated with bacterial biofilms. We examine the current understanding and research progress on the major mechanisms of antibiotic resistance in biofilms, including quorum sensing. We also discuss the potential strategies that may overcome biofilm-related antibiotic resistance, focusing on targeting biofilm EPSs, blocking quorum sensing signaling, and using recombinant phages.

• 식물병연구
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• 제8권2호
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• pp.78-83
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• 2002

Tobacco diseases have not been recorded until 1900s in Korea, where tobacco plants were introduced at early 1700s. Practical researches on the disease have been conducted since mid 1960s. Major ten tobacco diseases were mosaic caused by tobacco mosaic virus·potato virus Y·cucumber mosaic virus, bacterial wilt, hollow stalk, wild fire caused by angular leaf spot strain, black shank, brown spot, powdery mildew and fusarium wilt. But their annual occurrences were varied according to changes of tobacco varieties and their cultivating practices. As no useful chemicals, several biological tactics have been developed to control the viral or bacterial diseases that give significant economic damages on sustainable crop yield, but not practicable to field farming condition yet. Transgenic tobacco plants containing foreign disease resistant genes have been developed by current bio-technology, but not released to farmers yet. Though some disease-resistant tobacco varieties have been developed by the conventional breeding technology and currently used by farmers, their disease controlling efficacy have been diminished by occurrence of the new strain or race. Future research on tobacco diseases has been focused on technical development to produce high quality tobacco with less production cost, which leads Korean tobacco industry to keep its competence against foreign industry and decreasing overall market.

• The Plant Pathology Journal
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• 제19권5호
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• pp.253-256
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• 2003

Citrus canker disease is caused by bacteria Xanthomonas axonopodis .pv. Citri. Shiranuhi cultivar, a hybrid of Kiyomi tangor and Nakano No.3 ponkan was evaluated for resistance to citrus canker based on initiation of disease, percent area of lesion infected and growth rate of bacteria in the leaf under growth chamber condition. Significant differences between susceptible plant and resistant plants were observed in these assays. Resistant plants showed delayed disease symptoms compared to the susceptible plants after spray inoculation of the pathogen. The resistant verities, satsuma, yuzu, and Shiranuhi showed symptoms after six days where as susceptible, mexican lime showed the symptoms just after three days of inoculation. 18 days after inoculation, percent area of lesions developed on leaf and disease severity differed significantly in susceptible and resistant plants, and were ranked as follows: mexican lime > early satsuma =Shiranuhi =yuzu (P <, 0.01). However, 30 days after inoculation, percent area of lesion was further differentiated into resistant and highly resistant plants. That was ranked as follows: sweet orange> early satsuma =Shiranuhi =Kiyomi > yuzu (P < 0.01). These results indicate that host reaction to the bacterial was more distinct when the disease developed for a longer period. Growth rates of a citrus canker bacterium during 16 40 h also were distinct after infiltration into leaves of susceptible and resistant plants, and were ranked as follows: sweet orange> early satsuma =Shiranuhi =Kiyomi =yuzu (P < 0.01). Based on these results, we concluded that Shiranuhi is resistant to citrus canker as compared to Kiyomi, early satsuma, and yuzu.

• 한방안이비인후피부과학회지
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• 제16권1호
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• pp.94-99
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• 2003

Objectives : Gram-positive bacteria have became increasing resistant to antibacterial agents, and hence multi-drug-resistant bacterial pathogens are now a major problem in clinical medicine. There is, therefore, a need for new antibacterial agents. In the course of our screening program for potent antibacterial agent from medicinal plants, the extract of Salvia miltiorrhiza (S. miltiorrhiza) showed antibacterial activity against methcillin resistant Staphylococcus aureus (MRSA) and antibiotic-resistant S. aureus. Methods : S. miltiorrhiza was extracted with 80$\%$ EtOH. The extract was suspended in H2O and fractionated successively with hexane chloroform, ethyl acetate, and n-buthanol. The chloroform fraction, which showed the highest antibacterial activity(MICs, 78㎍/ml) against MRSA, was chromatographed on a silica gel column and recycling prep-LC to give the pure antibacterial component. Results and Conclusions : The second fraction among the chloroform soluble portion of an aqueous EtOH extract of S. miltiorrhiza root showed outstanding antibacterial activity against MRSA and antibiotic-resistant S. aureus compared to the other fraction. An active compound was isolated from the second fraction using silica gel column chromatoraphy and recycling prep-LC. Based on these data together with the IH-, 13C-NMR, mass and mp, the active compounds were identified tanshinone Ⅰ, dehydrotanshinone Ⅰ and cryptotanshinone. Among tanshinones, cryptotanshinone and dihydrotanshinone Ⅰ MICs against MRSA and antibiotics-resistant S. aureus were 12.5, 12.5 and 6.3㎍/ml, respectively.

• 한국어병학회지
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• 제13권2호
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• pp.111-119
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• 2000

군산내만에서 분리한 미생물총 Vibrio spp.(44균주), Pseudomonas spp.(42균주), Aeromonas spp.(26균주), Moraxella spp.(9균주), Enterobacteria spp.(6균주), Bordetella spp.(3균주), Alkaligenesis spp.(3균주), Staphylococcus spp.(3균주), Flavobacterium spp.(2균주)를 총 123주를 대상으로 Ampicillin(AM), Penicillin-G(PM), Rifampicin(RF), Streptomycin(SM), Oxolinic acid(OA), Nalidixic acid(NA), Oxytetracycline(OT), Amikacin(AK), 및 Enorfloxacin(EF)등의 약제에 대해서 감수성검사를 실시하였다. 공시약제에 대한 감수성균주는 42균주(34.1%)이었으며, 내성균주는 81균주(65.9%)로서 약제 내성율은 AM(54균주/43.9%), PM(47균주/38.2%) 및 RF(35균주/28.4%) 등에는 고빈도의 내성을 보였으며, SM(9균주/7.3%), OA(5균주/4.06%) 및 NA(1균주/0.8%)등에는 저빈도의 내성을 보였다. 그렇지만 OT, AK 및 NF에는 내성을 보이지 않았다. 내성 유형은 총 15유형(1-4제)으로서 이중 단일약제 내성 균주는 모두 35균주(28.4%)로서 AM(20균주/16.3%), PM(10균주/16.3%)및 RF(10균주/8.1%)약제에 내성 출현율이 높았다. 한편, 다제내성은 12유형을 나타내었으며, AM-PM-RF(16균주/13.4%), AM-PM(8균주/6.5%) 및 PM-RF(7균주/5.6%)유형이 비교적 출현빈도가 높았다. 따라서 본 해역은 다양한 약제에 내성을 나타내는 미생물총이 서식하고 있어서 향후 다제내성균이 빠르게 확산 되어 어류질병의 치료에 많은 어려움이 예상된다.

• 한국잠사곤충학회지
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• 제37권1호
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• pp.86-91
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• 1995

축엽세균병으로 알려진 피해뽕나무에서 진균인 Fusarium spp. 균이 분리되어 이를 구명하고 그 피해정도를 조사한 결과 1. 신소썩음증상은 세로로 긴 갈색의 병무늬가 시간이 경과할 수록 암갈색으로 변하고 흰곰팡이가 생기며, 축엽세균병증상은 잎이 말리고 신소에 수침상의 병반과 bacterial ooze가 보인다. 그러나 시간이 경과하면 구분이 어렵다. 2. 신소썩음증상의 피해율은 7.5%, 축엽세균병의 피해율은 4.4%였다. 3. Fusarium spp. 균의 분리는 신소썩음증상에서 높았고, Pseudomonas균의 분리는 축엽세균병 증상에서 많았다. 또한 병원성도 같은 경향을 보였다. 4. 수원 등 3지역 모두에서 부위별 병원성 Fusarium spp. 균의 분리율은 병반에서 30cm 부위에서 보다 병진전부위에서 더 높았다. 5. 수원 등 3지역 모두에서 개량뽕의 신소썩음증상 피해가 가장 많았다. 그러나 청올뽕의 신소썩음증상 피해는 조사 품종중에 가장 적었다.

• Pediatric Infection and Vaccine
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• 제12권2호
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• pp.157-165
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• 2005

목 적 : 화상의 병태 생리에 대한 지식 증가와 효과적인 항균제의 이용 및 상처의 괴사조직을 조기에 제거하는 수술 방법의 도입으로 최근 사망률이 감소하고 있으나, 아직도 세균 감염으로 인한 패혈증과 폐렴 등의 합병증이 사망의 가장 큰 원인이 되고 있다. 최근 내성균주의 증가로 적절하고도 제한적인 항균제 선택의 중요성이 증대되고 있다. 특히 Acinetobacter의 multi-drug resistant 균주는 최근 들어 관심의 대상이다. 중환자실의 MRSA, VRE 등의 균주가 증가되고 있는 우리나라의 실정에서 소아 연령의 화상부위 세균 감염 양상을 파악하고 각 균주에 따른 항균제 내성의 추이를 파악하여 적절한 항균제 선택으로 소아 화상 부위의 치료에 도움이 되고자 한다. 방 법 : 1999년 1월부터 2002년 12월까지 4년간 한림대학교 의료원 한강성심병원 화상 센터에 입원한 만 15세 이하 환아 중, 화상 부위 세균 배양 검사 양성으로 나타난 213명, 406검체를 대상으로, 의무기록의 후향적 고찰을 통하여 감염세균 및 항균제 감수성 양상을 조사, 분석하였다. 결 과 : 1) 총 213명의 환아 중 남아 127명(59.6%), 여아 86명(40.4%)이었다. 나이별로는 1~5세까지의 학령 전기에서 132명(62.0%)으로 가장 많았고, 1개월~1세의 영아기 45명(21.1%), 6~10세의 학령기 24명(11.3%) 순이었다. 2) 화상의 종류로는 열탕 화상이 167명(78.4%)으로 가장 많았고, 다음으로 화염 화상이 35명(16.4%), 접촉 열화상 6명(2.8%) 순이었다. 3) 총 213명 406검체 중 64검체(15.8%)에서 두 종류 이상의 균주가 분리되었다. P. aeruginosa가 236검체(58.1%)에서 분리되어 가장 흔한 원인균이었다. Enterococcus species가 73검체(18.0%), S. aureus가 51검체(12.6%), S. epidermidis가 48검체(11.8%)에서 분리되었다. 그 다음으로 Streptococcus species, Acinetobacter species, E. coli 순이었다. 4) P. aeruginosa의 경우 항균제에 대한 내성률은 trimethoprim-sulfamethoxazole 100%, cephalothin 98.1%, ampicillin-sulbactam 96.2%, ampicillin 95.3%, ceftriaxone 95.2%, tobramycin 93.7%, cefoperazone 68.9%, ceftazidime 67.7%이었다. 5) Enterococcus species는 tetracycline 63.9%, streptomycin 45.5%, gentamicin 36.1%, penicillin G 13.7%의 내성을 보였다. 6) S. aureus는 gentamicin 89.7%, tetracycline 86.2%, ciprofloxacin 86.2%, penicillin G 84.3%, oxacillin 78.4%, erythromycin 76.5%의 내성을 보였다. 7) S. epidermidis는 oxacillin 81.2%, erythromycin 79.2%, gentamicin 76.2%, penicillin G 70.8%, fusidic acid 70.3%, tetracycline 61.9%의 내성을 보였다. 8) Acinetobacter species는 ampicillin-sulbactam 100%, gentamicin 85.7%, ampicillin 83.3%, piperacillin 61.5%, aztreonam 53.3%의 내성을 보였다. 결 론 : P. aeruginosa의 선택적 항생제 중 cefoperazone 68.9%, ceftazidime 67.7% 등 높은 내성을 보였고, imipenem 역시 25.9%의 내성을 나타냈다. 현재 P. aeruginosa에 대한 백신이 개발 중이나 효과에 대해선 더 많은 연구가 필요할 것이다. S. aureus는 penicillin G 84.3%, oxacillin 78.4% 등의 높은 내성을 보였으나, vancomycin 0%, teicoplanin 2.2%로 아직 낮은 내성률을 보였다. Acinetobacter species는 최근 계속 증가하는 multi-resistant drug 양상을 보이고 있어 향후 항균제 선택에 있어 신중한 주의가 필요하다.