• Pediatric Infection and Vaccine
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• 제22권3호
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• pp.178-185
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• 2015

목적: 국내 소아 그람음성균혈증에서 항생제 내성변화 및 항생제 사용량과의 관계를 분석하였다. 방법: 최근 10년간 18세 이하 입원 환자의 혈액에서 분리된 그람음성균의 항생제 내성률 변화 및 항생제 사용량과의 관계를 분석하였다. 결과: 폐렴막대균, 대장균, 녹농균, 아시네토박터 바우마니의 분리율은 연간 혈액배양 1,000건당 각각 4.6례, 3.5례, 3.4례 및 2.2례였다. 폐렴막대균에서 광범위 세팔로스포린에 대한 내성변화는 없었으나 2010년부터 카바페넴 내성 폐렴막대균이 동정된 후 점차 빈도가 증가하였다. 대장균의 광범위 세팔로스포린 내성이 10%에서 50%로 아시네토박터 바우마니의 카바페넴 내성이 11%에서 71%로 크게 증가하였다(P for trend <0.01). 녹농균은 여러 항생제에 높은 내성을 보였으나 유의한 내성변화를 보이지 않았다. 대장균의 cefepime 내성과 cefepime 사용량 사이에 유의한 양의 상관관계를 보였다(r=0.900, P=0.037). 결론: 국내 소아에서 발생한 그람음성균 균혈증 분석시 카바페넴 및 광범위 세팔로스포린 내성이 증가하였고 일부에서 항생제 사용량과의 관련성을 확인하였다. 이는 원내 경험적 항생제 결정시 중요한 고려 사항이며 추후에도 지속적인 원내 항생제 사용량 및 내성률에 대한 감시가 필요하겠다.

• 미생물학회지
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• 제54권4호
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• pp.428-435
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• 2018

본 연구는 담수환경에서 항균활성을 보유한 미생물을 발굴하고, 활성 증진을 위해 배양조건을 최적화하는 것이다. 상주시 중동면 오상저수지에서 시료를 채취하여 38종의 미생물을 순수분리하였다. 16S rRNA 염기서열 분석에 근거하여 Proteobacteria강(22종), Actinobacteria강(7종), Bacteroidetes강(6종), Firmicutes강(3종)으로 구성되어있는 것을 확인하였다. 메티실린내성 황색포도상구군 등 10종의 유해미생물에 대한 항균활성을 보유한 Burkholderia sp. OS17 균주를 선발하였다. 항균활성 증진을 위한 상용배지, 온도, 초기 pH별 생육 및 항균활성 비교실험을 수행하였다. OS17 균주는 YPD 배지, $35^{\circ}C$, pH 6.5로 배양했을 때 가장 활성이 높았다. LB, NB, TSB, R2A 배지와 $20^{\circ}C$, $25^{\circ}C$ 배양했을 때는 생장은 가능하나 항균활성이 전혀 없었다. 이전결과를 바탕으로 YPD 배지, $35^{\circ}C$에서 배양하면서 5 L fermenter를 이용하여 생육, 항균활성, pH 확인을 통해 배양 48시간을 최적 배양시간으로 선정하였다. 항균활성을 보유한 미생물의 배양 최적화는 항균물질 생산에 영향을 미치고, 이는 상업적 응용에 이점으로 작용할 수 있다.

• 대한본초학회지
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• 제30권5호
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• pp.15-21
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• 2015

Objectives : Methicillin-resistantStaphylococcus aureus(MRSA) is a human pathogen. New antibacterial agents are needed to treat MRSA-related infections. This study investigated the antibacterial activity of EtOH 70% extracts ofTonghyeonipal-dan(THD) which prescription is composed of oriental medicine against MRSA.Methods : The antibacterial activity of THD was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method, Checkerboard dilution test, and Time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors were used.Results : The minimum inhibitory concentration (MIC) of THD is 1,000~2,000 μg/mL against MRSA. In the checkerboard dilution test, fractional inhibitory concentration index (FICI) of THD in combination with antibiotics indicated synergy or partial synergism againstS. aureus. Furthermore, a time-kill assay showed that the growth of the tasted bacteria was considerably inhibited after 24 h of treatment with the combination of THD with selected antibiotics. For measurement of cell membrane permeability, THD 500 μg/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 (NaN3) were used as an inhibitor of ATPase. TX, TRIS, DCCD and NaN3 cooperation againstS. aureusshowed synergistic action.Conclusions : Accordingly, antimicrobial activity of THD was affected by cell membrane and inhibitor of ATPase were assessed. These results suggest that THD has antibacterial activity, and that THD extract offers great potential as a natural antibiotic against MRSA.

• Journal of Dairy Science and Biotechnology
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• 제22권2호
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• pp.107-112
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• 2004

과산화수소 형태의 반응성 산소에 대한 Lactobacillus Spp., Bifidobacterium spp. 및 Bacillus coagulans의 저항성과 세포 내에서 생성능력을 측정하기 위하여 본 연구가 수행되었다. Lactobacillus spp. 중에서 높은 과산화수소 저항성을 나타낸 균주는 L. acidophilus CU4111와 L. casei Cu4114인 것으로 나타났고 가장 낮은 저항성을 보인 균주는 L. brevis Cu4206이었다. Bifidobacterium longum CU4131은 높은 수준의 저항성을 나타내며 Bacillus coagulans를 포함하는 포자형성유산균주들은 전반적으로 과산화수소에 대한 저항성 이 높은 것으로 나타났다. 세포질 추출액 중의 과산화수소 함유 농도는 Bifidobacterium bifidum CU 4134가 가장 높고 Lactobacilli spp.의 세포질 추출액 중의 과산화수소 함유 농도는 L. casei CU 4114가 가장 높은 것으로 나타났다.

• 대한의생명과학회지
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• 제21권2호
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• pp.84-91
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• 2015

To provide guidelines for the empirical treatment of urinary tract infections, we observed annual changes in the occurrence frequency and antimicrobial susceptibility of urinary isolates in a university hospital in the Chungbuk province, South Korea, over a period of 10 years (2004~2013). Escherichia coli (38.2%), Enterococcus faecalis (11.7%), Klebsiella pneumoniae (7.3%), Pseudomonas aeruginosa (4.3%), E. faecium (4.3%), and Staphylococcus aureus (4.1%) were commonly isolated urinary pathogens. The prevalence of E. coli, E. faecium and Streptococcus agalactiae were significantly higher in females (P < 0.001), whereas E. faecalis, P. aeruginosa and S. aureus were significantly more common in male patients (P < 0.001). E. coli mostly frequently showed resistance to ampicillin (67.94%), followed by trimethoprim/sulfamethoxazole (36.06%) and ciprofloxacin (26.84%). Over the studied time period, resistance rates of E. coli to ciprofloxacin significantly increased (20.44% to 33.55%). Moreover, extended-spectrum $\beta$-lactamase (ESBL) producing isolates also significantly increased in E. coli (4.2% to 18.3%) and K. pneumoniae (9.6% to 26.9%). In addition, the proportion of vancomycin-resistant Enterococcus facium (VRE) also increased (15.7% to 25.0%). In conclusion, over the last 10 years, the proportions of ciprofloxacin resistant E. coli and multidrug-resistant bacteria, such as ESBL and VRE have significantly increased. This trend must be strictly controlled and demonstrates the need for more updated guidelines for the treatment of urinary tract infections.

• Journal of Microbiology and Biotechnology
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• 제25권12호
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• pp.2100-2105
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• 2015

Probiotic bacteria must have not only tolerance against bile salt but also no genes for antibiotic resistance. Leuconostoc citreum is a dominant lactic acid bacterium in various fermented foods, but it is not regarded as a probiotic because it lacks bile salt resistance. Therefore, we aimed to construct a bile salt-resistant L. citreum strain by transforming it with a bile salt hydrolase gene (bsh). We obtained the 1,001 bp bsh gene from the chromosomal DNA of Lactobacillus plantarum and subcloned it into the pCB4170 vector under a constitutive P710 promoter. The resulting vector, pCB4170BSH was transformed into L. citreum CB2567 by electroporation, and bile salt-resistant transformants were selected. Upon incubation with glycodeoxycholic acid sodium salt (GDCA), the L. citreum transformants grew and formed colonies, successfully transcribed the bsh gene, and expressed the BSH enzyme. The recombinant strain grew in up to 0.3% (w/v) GDCA, conditions unsuitable for the host strain. In in vitro digestion conditions of 10 mM bile salt, the transformant was over 67.6% viable, whereas only 0.8% of the host strain survived.

• 한국환경보건학회지
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• 제24권1호
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• pp.141-150
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• 1998

This study was performed to investigate the distribution of Yersiniae and correlation between Yersiniae and indicator organism by time and area in spring water located in northern part of Seoul. Samples collected from 46 spring waters located in four mountains(Dobong, Bukhan, Surak, Bulam) were inspected to detect Yersiniae and indicator organisms. And also there were examined bioserological characteristics and resistance of ahtibiotics of the isolated Yersiniae.The result were as follows. 1. The isolation rate of Yersiniae was 22% in February and 20% in April. The isolated species were 6 strains of Y. enterocolitica, 6 strains of Y. aldova, 4 strains of Y. intermedia and 43 strains of Y. pseudotuberculosis. The serotype of Y. pseudotuberculosis isolated from was all O:5 and biotype of Y. enterocolitica isolated from was all O:3. 2. The Geometric mean of standard plate count, coliform, and psychrotrophilic bacteria were 3.4 CFU/ml, 1.2 MPN/100 ml and 33.0 CFU/ml in February and 3.1 CFU/ml, 1.5 MPN/100 ml and 20.5 CFU/ml in April respectively. There was no significant difference by time and area but the indicator organisms were correlated significantly with each other (p<0.05). 3. Because detection of Yersiniae was not statistically associated with indicator organism, Yersiniae can be detected in the spring water approved microbiologically (p<0.05). 4. The Yersiniae isolated were resistant to Ampicillin, Colistin, Carbenicillin and Coilstin. All isolaed Y. enterocolitica were resistant to Ampicillin (100%). In the case of Y. pseudotuberculosis, only 1 of 3 isolated was resistant to Colistin but susceptible to other antibiotics.

• 대한의생명과학회지
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• 제13권1호
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• pp.47-53
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• 2007

Due to wide abuse of antibiotics both in human and livestock use, the advent and spread of multidrug resistant (MDR) pathogens becomes a serious health problem all over the world. Since the development of new antibiotics is at a standstill in pharmaceutical industry, the choice of therapeutic antibiotics is getting narrower. In this study, in an effort to search new antibiotics, the antimicrobial activity of Paenibacillus DY1 isolated from Korean soil was characterized on its growth inhibition spectrum against various health threatening MDR strains, with its stability and chemical structure. Extracellular culture filtrate of Paenibacillus DY1 effectively inhibits the growth of all the tested MDR enteropathogenic Eshcherichia coli, enterohemolytic E. coli, and enterotoxigenic E. coli strains, at a similar level to that on the nonresistant control E. coli strains. It showed significant growth inhibition effect against the causative agents of class one legal communicable disease, MDR Salmonella typhi, MDR Salmonella paratyphi A, food poisoning bacteria, MDR Salmonella typhimurium, and other MDR Salmonella spp. The growth of all of 10 different MDR Shigella spp. strains and 6 different Vibrio spp. strains tested was also inhibited. The antimicrobial activity of Paenibacillus DY1 was well preserved after heat treatment, and was also stable in both alkaline and acidic environment. The antimicrobial activity was partially purified with Diaion HP20 column and TLC. By NMR study, the putative structure of the activity was postulated as an alkane having hydroxyl groups.

• 한국작물학회지
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• 제35권2호
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• pp.132-136
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• 1990

수도 흰잎마름병(Xanthomonas campestris pv. oryzae) 병원세균(K1)의 조직내에서의 증식과 이동 그리고 수공을 통해 추출되는 병원세균의 농도를 조사한 결과를 요약하면 다음과 같다. 1. 저항성 품종에서는 접종 3일후에 약 $10^3$cfu/$\textrm{cm}^2$로 12일까지 큰 변화가 없었으나 리병성 품종에서는 접종 6일에 약 $10^4$cfu/$\textrm{cm}^2$에서 접종 12일에는 약 $10^{8}$-$10^{9}$cfu/$\textrm{cm}^2$로 계속 증식하였다. 2. 병원세균의 접종부위로부터 상, 하향 이동속도 및 증식속도는 상향이동이 약간 빠른 경향이었으며 리병성 품종에서 빠른 증식과 이동속도를 보여 저항성과 밀접한 관계가 있었다. 3. 병원세균의 증식 및 이동은 생육시기에 따른 차이는 없었다. 4. 감염된 잎의 수공을 통해 나오는 병원세균의 농도는 조직내에서 병원세균의 증식 및 이동과 일치하였으며 저항성과도 밀접한 관계가 있었다.

• The Plant Pathology Journal
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• 제19권5호
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• pp.239-247
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• 2003

In Korea, a local soybean (Glycine max) genotype 56l. was found to be strongly resistant to a virulent bacterial strain of a Pseudomonas sp. SN239. Specific genes involved in the resistance of the soybean genotype 561 were identified and the pattern of gene expression against the Pseudomonas infection was analyzed using differential-display reverse transcription PCR (DDRT-PCR). More than 126 cDNA fragments representing mRNAs were induced within 48 hours of bacteria inoculation. Among them, 28 cDNA fragments were cloned and sequenced. Twelve differentially displayed clones with open reading frames had unknown functions. Sixteen selected cDNA clones were homologous to known genes of other organisms. Some of the identified cDNAs were pathogenesis-related (PR) genes and PR-like genes. These cDNAs included a putative calmodulin-binding protein; an endo-l,3-1,4-$\bate$-D-glucanase; a $\bate$-1,3-endoglucanase; a $\bate$-1,3-exoglucanase; a phytochelatin synthetase-like gene; a thiol protease; a cycloartenol synthase; and a putative receptor-like serine/threonine protein kinase. Among them, four genes were found to be putative PR genes induced significantly by the Pseudomonas infection. These included a calmodulin-binding protein gene, a $\bate$-1,3-endoglucanase gene, a receptor-like serine/threonine protein kinase gene, and pS321 (unknown function). These results suggest that the differentially expressed genes may mediate the strong resistance of soybean 561 to the strain SN239 of Pseudomonas sp.