• 대한수의학회지
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• 제24권1호
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• pp.40-49
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• 1984

To investigate the factors influencing the artifical transformation in Escherichia coli, E. coli C600 was transformed by pBR322 DNA with tetracycline and ampicillin resistant gene purified by CsCl-Etbr equilibrium density gradient centrifugation from E.coli HB 101. The influencing factors in the transformation such as concentration of calcium chloride, time of ice incubation, temperature and time of heat shock, time of gene expression, effects of plasmid DNA concentration and adding time were examined in these experiments. The results obtained were as follows; 1. The highest transformation frequency was observed in the treatments of 100 mM $CaCl_2$ before heat shock and the treatment of $CaCl_2$ was essential step in the process of E. coli transformation. 2. The highest transformation frequency was observed in the treatment of heat shock at $42^{\circ}C$ for 4 min. or $37^{\circ}C$ for 6 min., but the prolonged heat shock resulted a decreased transformation frequency. 3. Treatments of ice incubation at $0^{\circ}C$ for 45 min. before heat stocks or at $0^{\circ}C$ for 30min. after heat shock resulted an increased transformation frequency. 4. There was a linear relationship between DNA concentration and transformation frequency at the concentration of $8{\times}10^3$ recipient cells. The highest transformation frequency reached in carte of 7 mcg of donor DNA, but above 1 mcg of DNA concentration, transformation frequency was not remarkably increased. Addition of donor DNA just after the treatment of $CaCl_2$ was the best. 5. The best condition of gene expression at $37^{\circ}C$ were 40min. for TC-resistant gene and 100min. for AP-resistant gene. TC-resistant gene was higher in the transformation frequency and faster in the gene expression time than AP-resistant gene. In these results, the best conditions for the transformation of E. coli C 600 with pBR322 DNA were: treatment with 100mM $CaCl_2$, ice incubation at $0^{\circ}C$ for 45 min, heat shock at $42^{\circ}C$ for 4 min., 30 min. of ice incubation and incubation at $37^{\circ}C$ for 100min. for gene expression in that order.

• 대한미생물학회지
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• 제13권1호
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• pp.1-5
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• 1978

Listeria monocytogenes infection was considered a rather rare disease and occurs mostly either in newborn babies or in young children. However, there has been increasing reports of this infection in elderly person with various underlying disease. Recently we have experienced two cases of Listeria meningitis; one in a 4-year-old male with an acute lymphoblastic leukemia, and the other in a 43-year-old female with a breast cancer. Both were on various chemotherapeutic agents for their primary diseases when the organism, L. monocytogenes was found in their celebospinal fluid(CSF). The degree of CSF pleocytosis were quite different by cases. The former case showed a marked increase, $3,350/mm^3$, and the latter slight, $410/mm^3$, Both showed a slight decrease of CSF glucose ranging 39 to 43mg/100ml. It seems that a routine CSF analysis bears a limitted value in the diagnosis or Listeria meningitis. A direct smear of CSF with Gram's stain revealed gram-positive bacilli in one case, but none in the other. Bacterial culture of CSF yielded plenty colonies in one case, but a few in the other. It seems that isolation of L. monocytogenes must not be considered very easy, and a negative direct smear does not necessarily mean a negative culture. The two isolates we obtained showed the typical cultural and biochemical characteristics of L. monocytogenes and were found to belong to serotypes 1b and 4b. It was our experience that the identification of this organism was not very much matter because of its distinct characteristics, but the most important matter was how to think of the possibility of this organism at the begining. The two isolates were both susceptible to cephalothin, chloramphenicol, erythromycin, tetracycline and gentamicin; intermediate to ampicillin, penicillin and kanamycin; and resistant to cloxacillin.

• 한국어병학회지
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• 제7권1호
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• pp.37-46
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• 1994

서해안 일원의 가온 양만장 사육조로부터 분리한 E. tarda균에 대한 약제내성검사 및 내성균의 내성인자 전달 시험을 실시하였다. 공시한 항생제에 대한 내성률은 LM, PM, SD, SF 등에는 100%, AP, CH, SM, OT 및 CP 등에는 89% 이상, OA 및 KM에는 70% 정도 그리고 AK, GM 및 EF 등에는 30% 이하의 내성률을 보였으며, 이와같은 내성률은 각 양만장에서 분리한 균주간에 차이를 보이지 않았다. 내성유형은 총 34유형으로 모든 분리균주가 8~14제의 다제내성을 보였으며, 그 중 LM PM SD SF CP CH SM OT AP OA KM(22주, 21.4%) 및 LM PM SD SF CP CH SM OT AP OA(12주, 11.7%) 유형등이 고빈도로 출현하였다. 내성균의 내성인자 전달유형은 총 55형으로 단제에서 13제까지의 다양한 내성인자가 전달되었는데, 그 중 LM PM SD SF CP CH SM OT AP OA(10주. 10%), LM PM SD SF CP CH SM OT AP OA KM(7주, 7%) 및 LM PM SD SF CP CH AP OA(7주, 7%) 등의 다제내성유형이 고빈도의 전달률을 보였으며, 약재별로는 GM, EF 및 AK 등에는 저빈도(0~20%), OT, SM, KM 및 OA 등에는 중등도(49~62%), AP, PM, LM, SF, CP, CH 및 SD 등에는 고빈도(71~94%)로 내성인자를 전달하였다.

• 한국동물위생학회지
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• 제34권1호
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• pp.45-54
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• 2011

This study was conducted to investigate the distribution of Salmonella spp. from pigs and cattle in slaughterhouse, the antimicrobial resistance pattern and the prevalence of resistance genes of isolates. A total of 640 fecal samples from pigs and cattle in slaughterhouse were collected for isolation of Salmonella spp.. Isolation rate was revealed as 15% in pigs and 1.6% in cattle. As result of serotyping, group B (56.6%) were identified as most common in pigs and cattle isolates, in order of group C (24.5%) and group E (15.1%). S. Typhimurium (50.9%) was most common serotype. The major serotypes were in order of S. Rissen and S. London (11.3%) and S. Riggil (7.6%). In antimicrobial test, all isolates were demonstrates susceptibility to nitrofurantoin. But isolates were revealed resistance other antibiotics in order of tetracycline (64.6%), streptomycin (68.3%), ampicillin and amoxicillin (56.3%) and spectinomycin (47.9%). With polymerase chain reaction, antimicrobial resistance gene strA (75.0%) and aadA1 (3.1%) were detected in streptomycin resistance isolates and tetA (94.3%) and tetB (11.3%) gene were detected in tetracycline resistant isolates, but tetG was not detected. Class 1 integron gene was detected in all Salmonella isolates.

• 한국미생물·생명공학회지
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• 제33권3호
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• pp.169-177
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• 2005

본 연구는 어업이나 농업 등의 인간활동에 의하여 상당한 영향을 받고 있는 순천만 갈대의 근권에서 이루어지는 정화작용에 있어 미생물의 역할을 조사하는 것에 중점을 두었다. 일반적으로 만은 환경 스트레스로 인한 갑작스런 충격을 감소시키는 완충지역으로서의 역할을 하는 것으로 알려져 있다. 갈대근권에서 이루어지는 정화기능에 있어 미생물의 역할을 밝히기 위한 첫 번째 노력의 일환으로 벤젠, 톨루엔, 또는 자일렌이 단일 탄소 및 에너지원으로 첨가된 농화배양법을 사용하여 BTEX를 분해할 수 있는 두 종류의 그람양성 세균을 순수분리하였다. 다양한 온도조건의 BTEX배지에서 이들 세균을 배양하는 동안 BTEX의 분해율 및 성장률을 주기적으로 조사한 결과 $37^{\circ}C$에서 가장 빠른 기질 분해율을 보였고 $42^{\circ}C$의 고온에서도 두 균 모두 잘 성장하는 것으로 나타났다. 본 연구에서 시험한 수은, 카드뮴, 납, 바륨, 철 대부분의 중금속에 강한 내성뿐만 아니라 ampicillin을 비롯한 시험한 5종류의 항생제 모두에 강한 내성을 나타냈다. 16S rRNA 유전자 서열과 다양한 표현형 및 형태학적 특성을 기초로 한 동정의 결과 BTEX를 분해할 수 있는 두 균주는 $95{\%}$상의 신뢰도로 Microbacterium sp.와 Rhodococcus sp.로 나타났고, 각 균주는 Microbacterium sp. EMB-1과 Rhodococcus sp. EMB-2로 명명하였다. 이러한 결과는 주요한 염습지 식물중의 하나인 갈대의 근권에서 살아가는 이들 균주들이 BTEX와 같은 석유로 오염된 근권 환경의 정화작용에 중요한 역할을 할 수 있음을 제시해주었다.

• 대한미생물학회지
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• 제19권1호
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• pp.11-24
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• 1984

Shigella remains to be an important enteric pathogen in this country for the present. Moreover, most of the isolates have become multiple resistant to various antibiotics which used to be drugs of choice for shigellosis. This study was made as an attempt to assess the present stage of antibiotic resistance and the incidence and transferability of R factors of Shigella. A total of one hundred and seventeen strains of Shigella isolated from patients in Seoul and provincial area between 1982 and 1983 were tested for their resistant to antimicrobial agents and transmission of R-plasmid. Antibiotic susceptibilities were determined by an agar dilution method. Muller hinton agar were used for the assay of drug resistance and tryptic soy broth were used for propagating medium for conjugation. Shigella isolated found to be one or more antibiotics were considered potential donor of R-plasmid. The following results were obtained. 1. Among 117 strains of Shigella isolated, 111 strains(94.9%) were found to be resistant to one or more drugs tested and 97.3% of these resistant strains were multiply resistant, indicating the multiply resistant strains were more than the single resistant strains. Only six strains were susceptible to all drugs tested. 2. Among 117 strains of Shigella isolated, 107 strains(91.5%) were resistant to Tetracyclin(Tc), 106 strains(90.6%) to Chloramphenicol(Cp) and Streptomycin(Sm), 97 strains(82.9%) to Ampicillin(Ap), 68 strains(58.1%) to Cephaloridine(Cr), 10 strains(8.5%) to Nalidixic acid(Na), 5 strains(4.3%) to Kanamycin(Km) and 2 strains(1.7%) to Rifampicin. No strain was resisfant to Amikacin(Ak) and Gentamicin(Gm). 3. All drug-resistant Shigella strains, except three, were multiply resistant to two or more drugs. Fifty eight strains were resistant to five drugs, followed by 26 strains resistant to dour drugs, 12 strains resistant to three drugs and 11 strains resistant to six drugs. 4. The 73% of multiply drug-resistant Shigella transferred their resistance to E. coli by conjugation and the resistance was considered to be mediated by R-plasmid. Resistance to Nalidixic acid and Rifampicin were not transferred by conjugation to recipient. As for the transferability of resistance to each seperate drug, Ap resistance was transferred with 73.2% frequence and Cm and Tc resistance were transferred with approximately 50-60% frequence whereas Sm and Cr resistance were transferred in 19.1-21.4% The other four drugs resistant failed to transfer their resistance to recipient. 5. As for the incidence and transferability of resistance to each seperate drug, the strains resistant to Tc and Cm were encountered most frequently with the rate of 91-92%, whereas transfer of Tc and Cm were low, 51-52%. The incidence of Sm resistance was very high(90.6%) but transferability of drugs resistance was much lower(25.4%). Though the incidence of Km reristance was much lower(4.3%) transferability of Km resistance was considerably higher(60%). 6. The greater the multiplicity of resistance, the greater was the likelihood that part of all of the resistance markers would be transferable.

• 한국어병학회지
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• 제9권2호
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• pp.195-201
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• 1996

군산근교의 양만장에서 애드와드병에 이환된 뱀장어로부터 총 96균주의 E.tarda균을 분리한 후 이들 분리균의 약제감수성 검사를 실시하고 아울러 내성균의 내성인자 전달 시험을 실시하였다. 공시한 모든 균주는 SM, AK, NF 및 GM등에는 100% 감수성을 보였으나, 대부분의 균주가 SD(86균주), AM(84균주), PM(80균주), NA(67균주), OT(44균주) 및 OA(37균주) 등의 내성을 보였다. 내성유형은 20유형으로서 거의 모든 균주가 2제 이상의 다제내성을 보였으며, 그중 SD-AM-PM-NA-OA(16균주), SD-AM-PM-NA(14균주), SD-AM-PM-NA-OT-OA(12균주), SD-AM-PM-OT(10균주) 및 SD-AM-PM-NA-OT(8균주) 유형등이 고빈도로 출현하였다. 내성균주의 내성인자 전달 빈도는 94균주중에서 78균주가 단계에서 6제까지의 다제내성인자의 전달을 보였다. 그중 AM 및 AM-PM-NA유형(8균주), PM,SD 및 AM-SD유형(6균주), AM-PM, PM-SD 및 AM-SD-OT유형(4균주)등이 고빈도 출현을 보였다. 이러한 결과는 양만장에서 다양한 항균제를 사용하였기 때문에 다제내성현상이 확산되어진 것으로 사료된다.

• Fisheries and Aquatic Sciences
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• 제21권2호
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• pp.6.1-6.10
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• 2018

The intention of this study was to identify the bacterial pathogens infecting Oreochromis niloticus (Nile tilapia) and Clarias gariepinus (African catfish), and to establish the antibiotic susceptibility of fish bacteria in Uganda. A total of 288 fish samples from 40 fish farms (ponds, cages, and tanks) and 8 wild water sites were aseptically collected and bacteria isolated from the head kidney, liver, brain and spleen. The isolates were identified by their morphological characteristics, conventional biochemical tests and Analytical Profile Index test kits. Antibiotic susceptibility of selected bacteria was determined by the Kirby-Bauer disc diffusion method. The following well-known fish pathogens were identified at a farm prevalence of; Aeromonas hydrophila (43.8%), Aeromonas sobria (20.8%), Edwardsiella tarda (8.3%), Flavobacterium spp. (4.2%) and Streptococcus spp. (6.3%). Other bacteria with varying significance as fish pathogens were also identified including Plesiomonas shigelloides (25.0%), Chryseobacterium indoligenes (12.5%), Pseudomonas fluorescens (10.4%), Pseudomonas aeruginosa (4.2%), Pseudomonas stutzeri (2.1%), Vibrio cholerae (10.4%), Proteus spp. (6.3%), Citrobacter spp. (4.2%), Klebsiella spp. (4.2%) Serratia marcescens (4.2%), Burkholderia cepacia (2.1%), Comamonas testosteroni (8.3%) and Ralstonia picketti (2.1%). Aeromonas spp., Edwardsiella tarda and Streptococcus spp. were commonly isolated from diseased fish. Aeromonas spp. (n = 82) and Plesiomonas shigelloides (n = 73) were evaluated for antibiotic susceptibility. All isolates tested were susceptible to at-least ten (10) of the fourteen antibiotics evaluated. High levels of resistance were however expressed by all isolates to penicillin, oxacillin and ampicillin. This observed resistance is most probably intrinsic to those bacteria, suggesting minimal levels of acquired antibiotic resistance in fish bacteria from the study area. To our knowledge, this is the first study to establish the occurrence of several bacteria species infecting fish; and to determine antibiotic susceptibility of fish bacteria in Uganda. The current study provides baseline information for future reference and fish disease management in the country.

• 한방재활의학과학회지
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• 제25권2호
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• pp.1-13
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• 2015

Objectives Methicillin-Resistant Staphylococcus aureus (MRSA) is a human pathogen and a major cause of hospital-acquired infections. New antibacterial agents that have not been compromised by bacterial resistance are needed to treat MRSA-related infections. In this study, we investigated the antimicrobial activity ofethanol extract of Haedokgeumhwa-san (HGH) which prescription is composed of korean medicine against MRSA. Methods The antibacterial activity of HGH extract was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method (minimal inhibitory concentration; MIC), checkerboard dilution test, and time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors. The checkerboard dilution test was used to examined synergistic effect of ampicillin, oxacillin, ciprofloxacin, vancomycin, gentamicin and norfloxacin in combination with HGH ethanol extract. A time-kill assay was performed a survival curve which was obtained by plotting viable colony counts depending on time on bacterial growth. Results The minimum inhibitory concentration (MIC) of ethanol extract (HGH) ranged from 1,000 to $2,000{\mu}g/mL$ against all the tested bacterial strains, respectively. We are able to confirm that HGH extract has potentially strong antibacterial activity. In the checkerboard dilution test, fractional inhibitory concentration index of HGH in combination with antibiotics indicated synergy or partial synergism against S. aureus. A time-kill study showed that the growth of the tested bacteria was considerably inhibited after 8 hr of treatment with the combination of HGH with selected antibiotics. For measurement of cell membrane permeability, HGH $250{\sim}1,000{\mu}g/mL$ along with concentration of Triton X-100 (TX) and Tris-(hydroxymethyl) aminomethane (Tris) were used. In the other hand, N,N-dicyclohexylcarbodimide (DCCD) and Sodium azide ($NaN_3$) was used as an inhibitor of ATPase. TX, Tris, DCCD and $NaN_3$ cooperation against S. aureus showed synergistic action. Accordingly, antimicrobial activity of HGH was affected by cell membrane and inhibitor of ATPase. Conclusions These results suggest that Haedokgeumhwa-san extract has antibacterial activity, and that HGH extract offers a potential as a natural antibiotic against MRSA.

• 미생물학회지
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• 제46권3호
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• pp.303-307
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• 2010

임상분리 균주인 A. baumannii 1625는 imipenem (carbapenem 계열)을 포함한 대부분의 ${\beta}$-lactam계열의 항생제들과 kanamycin, gentamicin, tobramycin 및 제 3세대와 4세대 cephalosporin 계열의 항생제들에 광범위한 내성을 나타내었고, 한국에서는 드문 IMP-1형 metallo-${\beta}$-lactamase (MBL)를 생성하는 균주임이 확인되었다. A. baumannii 1625는 약 2.5 kb 크기의 class 1 integron을 갖고 있었으며, 이 integron내에 aminoglycoside계열 내성 유전자인 accA4, carbapenem 계열 내성 유전자인 $bla_{IMP-1}$, 광범위한 ${\beta}$-lactam 내성 유전자인 $bla_{OXA-2}$ 유전자 cassette들이 차례대로 위치해 있음을 확인하였는데, 이것은 IMP-1형과 OXA-2형 ${\beta}$-lactamase의 유전자를 같은 integron내에 동시에 갖는 새로운 배열 및 구조로서 이전에 국내에서 보고된 바 없는 것이다. 이 2.5 kb 크기의 integron을 항생제 내성이 없는 E. coli에 형질전환 시켰을 때, imipenem, ampicillin, piperacillin, cefazolin, cefoperazone, aztreonam 등의 항생제들에 대하여 8배 이상 증가된 내성정도를 보였다. 이는 A. baumannii 1625의 integron이 다제내성을 부여하는 기능을 하고 있음을 보여준다.