• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.542-551
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• 2017

Small phytochemicals have been successfully adopted as antibacterial chemotherapies and are being increasingly viewed as potential antibiofilm agents. Some of these molecules are known to repress biofilm and toxin production by certain bacterial and yeast pathogens, but information is lacking with regard to the genes allied with biofilm formation. The present study was performed to investigate the inhibitory effect of burdock root extract (BRE) and of chlorogenic acid (CGA; a component of BRE) on clinical isolates of Klebsiella pneumoniae. BRE and CGA exhibited significant antibiofilm activity against K. pneumoniae without inflicting any harm to its planktonic counterparts. In vitro assays supported the ${\beta}$-lactamase inhibitory effect of CGA and BRE while in silico docking showed that CGA bound strongly with the active sites of sulfhydryl-variable-1 ${\beta}$-lactamase. Furthermore, the mRNA transcript levels of two biofilm-associated genes (type 3 fimbriae mrkD and trehalose-6-phosphate hydrolase treC) were significantly downregulated in CGA- and BRE-treated samples. In addition, CGA inhibited biofilm formation by Escherichia coli and Candida albicans without affecting their planktonic cell growth. These findings show that BRE and its component CGA have potential use in antibiofilm strategies against persistent K. pneumoniae infections.

• 대한두개안면성형외과학회지
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• 제21권2호
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• pp.127-131
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• 2020

A 60-year-old woman with a history of diabetes mellitus and chronic renal failure was admitted to the hospital with severe pain in the upper lip, which began 4 days prior to admission, accompanied by a bullous lesion and suspected cellulitis in the upper lip. Immediately after admission, as the patient's general condition worsened, tests revealed a non-ST elevated myocardial infarction, septic embolism of the lung, as well as septic shock. Her upper lip suddenly presented a gangrenous and necrotic change, which the tissue and blood culture confirmed to be a Klebsiella pneumoniae infection. After a quick response, the patient's general condition improved. Subsequently, serial debridement was performed to effectively clear away the purulent discharge. While under general anesthesia, the process confirmed full-layer necrosis of the upper lip including the orbicularis oris muscle. Almost half of the entire upper lip sustained a full-layer skin and soft tissue defect, with scar contracture. Six months later, to correct the drooling and lip sealing following the defects, a scar release and an Abbe flap coverage were performed considering both functional and aesthetic aspects. The follow-up revealed a favorable corrective result of the upper lip drooling, and the patient was satisfied from a functional perspective.

• Journal of Microbiology and Biotechnology
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• 제19권9호
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• pp.1065-1069
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• 2009

Of 143 clinical isolates of Klebsiella pneumoniae collected from Korean non-tertiary hospitals, 24 (16.8%) showed an extended-spectrum ${\beta}$-lactamase-positive phenotype. PCR and sequence analysis revealed the presence of TEM-116 (n=13), CTX-M-3 (n=5), CTX-M-14 (n=2), CTX-M-15 (n=3), and SHV-12 (n=16). Each of the 24 isolates encoded more than one ${\beta}$-lactamase, and seven isolates (29%) harbored two different SHV-type ${\beta}$-lactamase genes ($bla_{SHV-11}$ and $bla_{SHV-12}$) bounded by insertion sequence IS26 in a single transferable plasmid.

• 대한본초학회지
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• 제20권2호
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• pp.171-179
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• 2005

Objectives & Methods : In order to evaluate the in vivo synergic effect of Mawhangyounpye-tang which was a traditional poly-herbal formula has been used in the treatment of respiratory diseases in Korea, with quinolone antibiotic, ciprofloxacin (CPFX), the viable bacterial number and histopathological changes were monitored after experimental respiratory infection with Klebsiella peumoniae NCTC 9632. Results : The obtained results were as follows : 1. In CPFX group, the viable bacterial numbers were significantly decreased compared to that of control group and these were more dramatically decreased compared to that of single treatment with CPFX, respectively in concomitant treated groups with Mawhangyounpye-tang. 2. In control group, severe infiltration of inflammatory cells, hemorrhage and hypertrophy of alveolar linings were demonstrated at microscopical levels. However, these abnormal histopathological changes were significantly decreased compared to that of control group in CPFX group, and these were more dramatically decreased compared to that of single treatment with CPFX, respectively in concomitant treated groups with Mawhangyounpye-tang. 3. In CPFX group, the LSA (luminal surface of alveoli %) were significantly increased compared to that of control group and these were more dramatically decreased compared to that of single treatment with CPFX, respectively in concomitant treated groups with Mawhangyounpye-tang. Conclusions : It is considered that in vivo antibacterial activity of CPFX was dramatically increased by concomitant use of Mawhangyounpye-tang against Kebsiella pneumoniae NCTC 9632 infection of respiratory tract.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1699-1707
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• 2013

During the fermentative production of 1,3-propanediol under high substrate concentrations, accumulation of intracellular 3-hydroxypropionaldehyde will cause premature cessation of cell growth and glycerol consumption. Discovery of oxidoreductases that can convert 3-hydroxypropionaldehyde to 1,3-propanediol using NADPH as cofactor could serve as a solution to this problem. In this paper, the yqhD gene from Klebsiella pneumoniae DSM2026, which was found encoding an aldehyde reductase (KpAR), was cloned and characterized. KpAR showed broad substrate specificity under physiological direction, whereas no catalytic activity was detected in the oxidation direction, and both NADPH and NADH can be utilized as cofactors. The cofactor binding mechanism was then investigated employing homology modeling and molecular dynamics simulations. Hydrogen-bond analysis showed that the hydrogen-bond interactions between KpAR and NADPH are much stronger than that for NADH. Free-energy decomposition dedicated that residues Gly37 to Val41 contribute most to the cofactor preference through polar interactions. In conclusion, this work provides a novel aldehyde reductase that has potential applications in the development of novel genetically engineered strains in the 1,3-propanediol industry, and gives a better understanding of the mechanisms involved in cofactor binding.

• Journal of Microbiology and Biotechnology
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• 제31권10호
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• pp.1383-1392
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• 2021

Carbapenem-resistant Enterobacteriaceae (CRE) that produce Klebsiella pneumoniae carbapenemase are increasingly reported worldwide and have become more and more resistant to nearly all antibiotics during the past decade. The emergence of K. pneumoniae strains with decreased susceptibility to carbapenems, which are used as a last resort treatment option, is a significant threat to hospitalized patients worldwide as K. pneumoniae infection is responsible for a high mortality rate in the elderly and immunodeficient individuals. This study used Lactobacillus fermentum as a candidate probiotic for treating CRE-related infections and investigated its effectiveness. We treated mice with L. fermentum originating from the vaginal fluid of a healthy Korean woman and evaluated the Lactobacilli's efficacy in preventive, treatment, nonestablishment, and colonization mouse model experiments. Compared to the control, pre-treatment with L. fermentum significantly reduced body weight loss in the mouse models, and all mice survived until the end of the study. The oral administration of L. fermentum after carbapenem-resistant Klebsiella (CRK) infection decreased mortality and illness severity during a 2-week observation period and showed that it affects other strains of CRK bacteria. Also, the number of Klebsiella bacteria was decreased to below 5.5 log₁₀ CFU/ml following oral administration of L. fermentum in the colonization model. These findings demonstrate L. fermentum's antibacterial activity and its potential to treat CRE infection in the future.

• 대한영상의학회지
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• 제81권3호
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• pp.733-738
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• 2020

Klebsiella pneumoniae에 의해 발생하는 감염성 대동맥류는 드문 것으로 알려져 있다. 저자들은 감염성 대동맥류가 발생한 50세 남성에 대해 성공적으로 이루어진 혈관 내 치료를 보고하고자 한다. 진단은 혈액 배양 검사와 전산화단층촬영을 통해 이루어졌다. 시술 전 투여된 항생제로 인해 임상증상과 혈액 배양이 개선되었다. 시술 후 24개월 동안 환자는 안정된 상태였으며 감염성 대동맥류의 감소가 일련의 전산화단층촬영을 통해 확인되었다. 따라서 기저 질환으로 인해 외과적 치료를 할 수 없는 환자에서 혈관 내 치료는 선택적 항생제 사용 후 균혈증과 열이 조절되는 경우 감염성 대동맥류에 대한 치료 방법이 될 수 있다.

• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1252-1258
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• 2016

1,3-Propanediol (1,3-PD) is a valuable platform compound. Many studies have shown that the supplement of NADH plays a key role in the bioproduction of 1,3-PD from Klebsiella pneumoniae. In this study, the xylA and xylB genes from Escherichia coli were overexpressed individually or simultaneously in K. pneumoniae to improve the production of 1,3-PD by cofermentation of glycerol and xylose. Compared with the parent strain, the xylose consumption was significantly increased by the introduction of these two genes. The 1,3-PD titers were raised from 17.9 g/l to 23.5, 23.9, and 24.4 g/l, respectively, by the overexpression of xylA and xylB as well as their coexpression. The glycerol conversion rate (mol/mol) was enhanced from 54.1% to 73.8%. The concentration of 2,3-butanediol was increased by 50% at the middle stage but drastically decreased after that. The NADH and NADH/NAD⁺ ratio were improved. This report suggests that overexpression of xylA or xylB is an effective strategy to improve the xylose assimilation rate to provide abundant reducing power for the biosynthesis of 1,3-PD in K. pneumoniae.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.753-761
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• 2020

To determine the role of pyruvate dehydrogenase complex (PDHC) in Klebsiella pneumoniae, the growth and metabolism of PDHC-deficient mutant in glycerol-based medium were analyzed and compared with those of other strains. Under aerobic conditions, the PDHC activity was fourfold higher than that of pyruvate formate lyase (PFL), and blocking of PDHC caused severe growth defect and pyruvate accumulation, indicating that the carbon flux through pyruvate to acetyl coenzyme A mainly depended on PDHC. Under anaerobic conditions, although the PDHC activity was only 50% of that of PFL, blocking of PDHC resulted in more growth defect than blocking of PFL. Subsequently, combined with the requirement of CO₂ and intracellular redox status, it was presumed that the critical role of PDHC was to provide NADH for the anaerobic growth of K. pneumoniae. This presumption was confirmed in the PDHC-deficient mutant by further blocking one of the formate dehydrogenases, FdnGHI. Besides, based on our data, it can also be suggested that an improvement in the carbon flux in the PFL-deficient mutant could be an effective strategy to construct high-yielding 1,3-propanediol-producing K. pneumoniae strain.

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.872-881
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• 2012

The inhibitory effect of the Klebsiella pneumoniae ATCC 13883 strain caused by the hexane extract of Halimeda discoidea (Nor Afifah et al., 2010) was further evaluated by means of the microscopy view and its growth curves. The morphological changes of the K. pneumoniae ATCC 13883 cells were observed under the scanning electron microscope (SEM) and transmission electron microscope (TEM) after they were treated at minimum inhibitory concentration (MIC; 0.50 mg/ml) (Nor Afifah et al., 2010) for 12, 24, and 36 h. The results showed the severity of the morphological deteriorations experienced by the treated cells. The killing curve assay was performed for 48 h at three different extract concentrations (1/2 MIC, MIC, and 2 MIC). An increase in the extract concentration of up to 2 MIC value did significantly reduce the number of cells by approximately 1.9 $log_{10}$, as compared with the control. Identification of the potential compounds of the extract responsible for the antibacterial activity was carried out through the gas chromatography-mass spectrum (GC-MS) analysis of the active subfraction, and the compound E-15-heptadecenal was identified and suggested as the most potential antibacterial compound of this extract. The subsequent cellular degenerations showed by the data might well explain the inhibitory mechanisms of the suggested antibacterial compound. All of these inhibitory effects have further proven the presence of an antibacterial compound within H. discoidea that can inhibit the growth of K. pneumoniae ATCC 13883.