• Mycobiology
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• v.30 no.1
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• pp.18-21
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• 2002

Four arbuscular mycorrhizal fungal(AMF) inocula collected from three arable sites in Korea were used to determine plant growth, mycorrhizal root colonization rate and spore production in three different host plant species; Sorghum bicolor, Allium fistulosum, Tagetes patula. Growth of plant treated with AMF differed from those without AMF. Different AMF inocula showed significantly different root colonization rates and spore production of AMF on the wild plants, A. fistulosum and T. patula, but did not on the cultivated plant, S. bicolor. Results suggested that indigenous mycorrhizal fungal community would be important factors in mycorrhizal symbiosis, and play important roles in the plant succession.

• Mycobiology
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• v.46 no.4
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• pp.388-395
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• 2018

Radionuclides were deposited at forest areas in eastern parts of Japan following the Fukushima Daiichi Nuclear Power Plant incident in March 2011. Ectomycorrhizal (EM) fungi have important effects on radiocaesium dynamics in forest ecosystems. We examined the effect of colonization by the EM fungus Astraeus hygrometricus on the uptake of cesium (Cs) and potassium (K) by Pinus densiflora seedlings. Pine seedlings exhibited enhanced growth after the EM formation due to the colonization by A. hygrometricus. Additionally, the shoot Cs concentration increased after the EM formation when Cs was not added to the medium. This suggests that A. hygrometricus might be able to solubilize Cs fixed to soil particles. Moreover, the shoot K concentration increased significantly after the EM formation when Cs was added. However, there were no significant differences in the root K concentration between EM and non-EM seedlings. These results suggest that different mechanisms control the transfer of Cs and K from the root to the shoot of pine seedlings.

• Clinical and Experimental Pediatrics
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• v.64 no.11
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• pp.543-551
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• 2021

The human microbiome, which consists of a collective cluster of commensal, symbiotic, and pathogenic microorganisms living in the human body, plays a key role in host health and immunity. The human nasal cavity harbors commensal bacteria that suppress the colonization of opportunistic pathogens. However, dysbiosis of the nasal microbial community is associated with many diseases, such as acute respiratory infections including otitis media, sinusitis and bronchitis and allergic respiratory diseases including asthma. The nasopharyngeal acquisition of pneumococcus, which exists as a pathobiont in the nasal cavity, is the initial step in virtually all pneumococcal diseases. Although the factors influencing nasal colonization and elimination are not fully understood, the adhesion of opportunistic pathogens to nasopharyngeal mucosa receptors and the eliciting of immune responses in the host are implicated in addition to bacterial microbiota properties and colonization resistance dynamics. Probiotics or synbiotic interventions may show promising and effective roles in the adjunctive treatment of dysbiosis; however, more studies are needed to characterize how these interventions can be applied in clinical practice in the future.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.540-549
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• 2016

Plant residues serve as substrates for the proliferation and overwintering of plant pathogenic fungi in soil. Effects of the biocontrol fungus Trichoderma harzianum on the colonization of wheat straw by the plant pathogenic fungus Fusarium solani were investigated under different soil moisture regimes (-50 vs. -500 kPa) in non-sterile soil. T. harzianum ThzID1-M3 and/or F. solani were added along with wheat straw to non-sterile soils. ThzID1-M3, other Trichoderma species, and F. solani were monitored for a 21-day period using quantitative PCR. ThzID1-M3 reduced the colonization of F. solani on wheat straw (p < 0.05) under both moisture regimes, and F. solani reduced the colonization by ThzID1-M3 and other Trichoderma species (p < 0.05), thus suggesting competitive inhibition between ThzID1-M3 and F. solani. Colonization by ThzID1-M3 and generic Trichoderma was improved in the wet soil (p < 0.05), but colonization by F. solani did not differ between the two moisture conditions. Thus, the inhibitory effect of ThzID1-M3 was greater in the wet soil (p < 0.05). The growth competition between ThzID1-M3 and F. solani to colonize plant debris suggests that the biocontrol fungus T. harzianum may reduce the potential of the plant pathogen, F. solani, to survive and proliferate on crops.

• Pediatric Infection and Vaccine
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• v.22 no.1
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• pp.16-22
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• 2015

Purpose: The aim of this study was to identify the factors influencing the spontaneous decolonization period of vancomycin resistant enterococcus (VRE) species in pediatric patients. Methods: The medical records of patients presenting positive VRE cultures between January 2005 and November 2010 at a tertiary hospital in Seoul, Korea, were reviewed retrospectively. The subjects were divided into two groups according to the average number of days for decolonization (325 days). Clinical characteristics were compared between shorter VRE colonization patients (<325 days, n=41) and prolonged VRE colonization patients (>325 days, n=110). Results: There were 151 patients who had more than 1 year of follow up period or confirmed of VRE decolonization among patients who were identified with VRE. The average age at the time of initial VRE colonization was significantly younger in shorter decolonization group than in prolonged decolonization group (44.9 months vs 40.9 months, P =0.040). The prolonged decolonization group received more vancomycin treatments after VRE colonization in comparison with patients in shorter decolonization group (7.0% vs 27.2%, P =0.008). Conclusion: For the duration of VRE colonization, it was found that the initial age of acquiring VRE and use of antibiotics were important factors. Antibiotics should be used properly and precisely in order to treat infectious diseases and to control the colonization of antibiotic resistant bacteria.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.1
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• pp.43-50
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• 2018

Purpose: Clostridium difficile colonization and infection are commonly associated with poor outcomes in patients with pediatric inflammatory bowel disease (PIBD). We aimed to investigate the prevalence of C. difficile colonization and infection at the time of diagnosis and to evaluate risk factors associated with the development of C. difficile infection during the course of PIBD treatment. Methods: We retrospectively enrolled a total of 59 children who were newly diagnosed with PIBD at the tertiary medical center. All patients underwent C. difficile toxin assays and cultures initially and at every follow-up during the disease course. Kaplan-Meier survival analysis and Cox regression test were used for statistical analysis. Results: Initial cultures for C. difficile were positive in 13 (22.0%) of 59 PIBD patients, whereas initial toxin assays were positive in 3 patients (5.1%). During treatment, C. difficile cultures converted to positive in 28 (47.5%) in addition to 13 patients who were initially culture-positive, and C. difficile toxins converted to positive in 13 (22.0%) in addition to 3 originally toxin-positive patients. Antibiotic usage alone was significantly associated with the development of C. difficile colonization (p=0.011), and the length of hospitalization was associated with the development of C. difficile infection (p=0.032). Conclusion: C. difficile colonization and infection occur frequently during the disease course of PIBD. Antibiotic usage and longer hospital stay were significant risks factors for the conversion of C. difficile status in PIBD patients undergoing treatment.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.333-343
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• 2009

Here, we show that an endophytic bacterial strain, Enterobacter asburiae B1 exhibits the ability to elicit ISR in cucumber, tobacco and Arabidopsis thaliana. This indicates that strain B1 has a widespread ability to elicit ISR on various host plants. In this study, E. asburiae strain B1 did not show antifungal activity against tested major fungal pathogens, Colletotrichum orbiculare, Botrytis cinerea, Phytophthora capsici, Rhizoctonia solani, and Fusarium oxysporum. Moreover, the siderophore production by E. asburiae strain B1 was observed under in vitro condition. In greenhouse experiments, the root treatment of strain B1 significantly reduced disease severity of cucumber anthracnose caused by fungal pathogen C. orbiculare compared to nontreated control plants. By root treatment of strain B1 more than 50% disease control against anthracnose on cucumber was observed in all greenhouse experiments. Simultaneously, under the greenhouse condition, the soil drench of strain B1 and a chemical inducer benzothiadiazole (BTH) to tobacco plants induced GUS activity which is linked with activation of PR promoter gene. Furthermore, in Arabidopsis thaliana plants the soil drench of strain B1 induced the defense gene expression of PR1 and PDF1.2 related to salicylic acid and jasmonic acid/ethylene signaling pathways, respectively. In this study, for the main focus on root colonization by strain B1 associated with defense responses, bacterial cells of strain B1 was tagged with the gfp gene encoding the green fluorescent protein in order to determine the colonization pattern of strain B1 in cucumber. The gfp-tagged B1 cells were found on root surface and internal colonization in root, stem, and leaf. In addition to this, the scanning electron microscopy observation showed that E. asburiae strain B1 was able to colonized cucumber root surface.

• Journal of Applied Biological Chemistry
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• v.54 no.2
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• pp.120-125
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• 2011

In order to exploit Methylobacterium oryzae CBMB20 as of plant growth promoting agent, different inoculation methods have been evaluated. The present study aimed to evaluate soil, foliar, and soil+foliar inoculations of M. oryzae CBMB20 to improve the growth, fruit yield, and nutrient uptake of red pepper (Capsicum annuum L.) under greenhouse conditions. The population range of green fluorescent protein (gfp)-tagged M. oryzae CBMB20 using the three inoculation methods was 2.5-2.9 ${\log}_{10}$ cfu/g in the rhizosphere and 4.5-6.0 ${\log}_{10}$ cfu/g in the phyllosphere of red pepper plants. Confocal laser scanning microscopy results confirmed the colonization of M. oryzae CBMB20 endophytically on leaf surface. Plant height, fruit dry weight, and total biomass were significantly higher ($p{\leq}0.05$) in all M. oryzae CBMB20 inoculation methods as compared to non-inoculated control. Furthermore, uptake of mineral nutrients such as N, P, K, Ca, and Mg in red pepper plants in all M. oryzae CBMB20 inoculation methods was higher than in non-inoculated control. Comparative results of inoculation methods clearly demonstrated that soil+foliar inoculation of M. oryzae CBMB20 lead to the highest biomass accumulation and nutrient uptake which may be due to its efficient colonization in the red pepper rhizosphere and phyllosphere.

• Journal of Korean Neurosurgical Society
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• v.46 no.2
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• pp.123-129
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• 2009

Objective: This study was aimed to identify the incidence and risk factors of vancomycin-resistant enterococcus (VRE) colonization in neurosurgical practice of field, with particular attention to intensive care unit (ICU). Methods: This retrospective study was carried out on the Neurosurgical ICU (NICU), during the period from January. 2005 to December. 2007, in 414 consecutive patients who had been admitted to the NICU. Demographics and known risk factors were retrieved and assessed by statistical methods. Results: A total of 52 patients had VRE colonization among 414 patients enrolled, with an overall prevalence rate of 6.1%. E. faecium was the most frequently isolated pathogen, and 92.3% of all VRE were isolated from urine specimen. Active infection was noticed only in 2 patients with bacteremia and meningitis. Relative antibiotic agents were third-generation cephalosporin in 40%, and vancomycin in 23%, and multiple antibiotic usages were also identified in 13% of all cases. Multivariate analyses showed Glasgow coma scale (GCS) score less than 8, placement of Foley catheter longer than 2 weeks, ICU stay over 2 weeks and presence of nearby VRE-positive patients had a significantly independent association with VRE infection. Conclusion: When managing the high-risk patients being prone to be infected VRE in the NICU, extreme caution should be paid upon. Because prevention and outbreak control is of ultimate importance, clinicians should be alert the possibility of impending colonization and infection by all means available. The most crucial interventions are careful hand washing, strict glove handling, meticulous and active screening, and complete segregation.

• Korean Journal of Adult Nursing
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• v.28 no.6
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• pp.628-636
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• 2016

Purpose: This study examined the effects of a program designed to prevent ventilator-associated pneumonia (VAP) on VAP rate and endotracheal colonization. The program focused on aspiration prevention and oral care. Methods: A nonequivalent control group post-test only design was utilized. One hundred patients admitted to a medical intensive care unit (MICU) or coronary care unit (CCU) were assigned to either a experimental group (n=50) or a control group (n=50). The participants were selected 48 hours following an endotracheal intubation. VAP prevention program given to the experimental group includes keeping the head of the bed to $30^{\circ}{\sim}45^{\circ}$ high, maintaining continuous endotracheal cuff pressure at 25 cm $H_2O$, performing endotracheal suction before change position, and providing oral care with 0.1% chlorhexidine every four hours. The control group received usual care. Data were analyzed using t-test, $x^2$ test, Mantel-Haenszel $x^2$ and Cox proportional harzard regression model. Results: The experimental group showed a lower VAP rate than the control group although the difference was not statistically significant ($x^2=0.79$, p=.375). The experimental group showed lower colonization in tracheal secretion than the control group ($x^2=14.59$, p<.001). Conclusion: Results showed that a VAP prevention program is effective in reducing colonization of tracheal secretion. Therefore, VAP prevention programs are recommended as an ICU nursing intervention.