INTRODUCTION: To prevent hemodialysis-related infections, it is important to maintain hemodialysis system without microbial contamination. In May 2003, routine surveillance showed that dialysis water from dialysis port was contaminated with bacteria. To identify the causes of the contamination, we conducted an investigation as follows. METHODS: Patients undergoing dialysis were carefully monitored to see whether evidences of pyrogenic reactions or infections were present. Factors that could have influence on bacterial contamination in hemodialysis systems were thoroughly examined. In addition, microbiologic surveillances were done 7 times in 1 month. RESULTS: Although pyrogenic reactions or bacteremia did not occur, R. pickettii was repeatedly isolated above the Association for the Advancement of Medical Instrumentation (AAMI) standards from almost all dialysis units. Bacterial counts of specimens were higher in the proximal part of the water supply tube than the other parts in all dialysis machines. The colony count of R. pickettii exceeded the maximum level of technical limit in the specimens collected from the dialysis machines in the early morning after intermission of 48 hours. The structure of the supply tube was suspected as the origin of the colonization because stagnant water is a reservoir for bacterial multiplication. After remodeling the structure of the water supply tube, neither R. pickettii nor any other bacteria were isolated. CONCLUSION: Our investigation successfully identified the source of R. pickettii contamination of reverse osmosis water. Appropriate corrective measures for water distribution systems of hemodialysis center could prevent outbreak of dialysis-associated illnesses.
Bacteremia ; Bacteria ; Bacterial Load ; Colon ; Dialysis ; Humans ; Osmosis ; Ralstonia ; Ralstonia pickettii ; Renal Dialysis ; Water ; Water Supply

Ralstonia solanacearum strain PRS-84 used in this study was isolated from diseased Pogostemon cablin plants in our previous study.The competent cells of R.solanacearum strain PRS-84 were transformed by electroporation with Tn5 transposon and then were plated on TTC agar plates containing kanamycin to select for kanamycin-resistant colonies.The detection of kanamycin-resistant gene in kanamycin-resistant colonies was performed by PCR.Further,the flanking fragments of Tn5 transposon insertion site in the mutants were amplified by inverse PCR,and the flanking fragments were sequenced and analyzed.The results indicated that the kanamycin-resistant colonies were obtained in the transformation experiment of R.solanacearum strain PRS-84 by electroporation with Tn5 transposon.A specific band of approximately 700 bp was amplified by PCR from kanamycin-resistant colonies.The flanking sequences of Tn5 transposon insertion site in the transformants were obtained by inverse PCR.After sequencing and sequence analysis of Tn5 transposon insertion site in mutants,we preliminarily speculated that the Tn5 transposon inserted in the typ A gene,rec O gene and gid A gene in three mutants,respectively.A random mutagenesis system of R.solanacearum strain PRS-84 by electroporation with Tn5 transposon has been established,and the Tn5 insertion mutants have been obtained.This study might facilitate the creation of mutant library and the discovery of the virulence gene of R.solanacearum isolated from P.cablin.
DNA Transposable Elements ; Electroporation ; Genes, Bacterial ; Mutagenesis, Insertional ; Pogostemon ; microbiology ; Ralstonia solanacearum ; genetics ; Virulence

The culture filtrate of Lentinula edodes shows potent antimicrobial activity against the plant pathogenic bacteria Ralstonia solanacearum. Bioassay-guided fractionation was conducted using Diaion HP-20 column chromatography, and the insoluble active compound was not adsorbed on the resin. Further fractionation by high-performance liquid chromatography (HPLC) suggested that the active compounds were organic acids. Nine organic acids were detected in the culture filtrate of L. edodes; oxalic acid was the major component and exhibited antibacterial activity against nine different phytopathogenic bacteria. Quantitative analysis by HPLC revealed that the content of oxalic acid was higher in the water extract from spent mushroom substrate than in liquid culture. This suggests that the water extract of spent L. edodes substrate is an eco-friendly control agent for plant diseases.
Agaricales ; Bacteria* ; Chromatography ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Lentinula* ; Oxalic Acid* ; Plant Diseases ; Plants ; Ralstonia solanacearum ; Shiitake Mushrooms* ; Water

Culture filtrates of six different edible mushroom species were screened for antimicrobial activity against tomato wilt bacteria Ralstonia solanacearum B3. Hericium erinaceus, Lentinula edodes (Sanjo 701), Grifola frondosa, and Hypsizygus marmoreus showed antibacterial activity against the bacteria. Water, n-butanol, and ethyl acetate extracts of spent mushroom substrate (SMS) of H. erinaceus exhibited high antibacterial activity against different phytopathogenic bacteria: Pectobacterium carotovorum subsp. carotovorum, Agrobacterium tumefaciens, R. solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, X. axonopodis pv. vesicatoria, X. axonopodis pv. citiri, and X. axonopodis pv. glycine. Quantitative real-time PCR revealed that water extracts of SMS (WESMS) of H. erinaceus induced expressions of plant defense genes encoding beta-1,3-glucanase (GluA) and pathogenesis-related protein-1a (PR-1a), associated with systemic acquired resistance. Furthermore, WESMS also suppressed tomato wilt disease caused by R. solanacearum by 85% in seedlings and promoted growth (height, leaf number, and fresh weight of the root and shoot) of tomato plants. These findings suggest the WESMS of H. erinaceus has the potential to suppress bacterial wilt disease of tomato through multiple effects including antibacterial activity, plant growth promotion, and defense gene induction.
1-Butanol ; Agaricales* ; Agrobacterium tumefaciens ; Bacteria ; Glycine ; Grifola ; Lycopersicon esculentum* ; Oryza ; Pectobacterium carotovorum ; Plants ; Ralstonia solanacearum ; Real-Time Polymerase Chain Reaction ; Seedlings ; Shiitake Mushrooms ; Water* ; Xanthomonas

Fourteen compounds were isolated from Dalbergia odoriferae and purified by repeated column chromatography on silica and sephadex LH-20 gel and structurally identified by spectral analysis. These compounds were identified as 4, 9-dimethoxy-3-hydroxypterocarpan (1), medicarpin (2), 2', 4', 5-trihydroxy-7-methoxyisoflavone (3), 2', 3', 7-trihydroxy-4'-methoxyisoflavan (4), formononetin (5), 3, 8-dihydroxy-9-methoxypterocarpan (6), koparin (7), 3-hydroxy-9-methoxypterocarp-6a-ene (8), 2'-hydroxyformononetin (9), stevenin (10), 2', 7-dihydroxy-4', 5'-dimethoxyisoflavone (11), lyoniresinol (12), 2, 4-dihydroxy-5-methoxy-benzophenone (13) and neokhriol A (14). Compounds 1, 3, 4, 6, 8, 12 and 14 were isolated from this plant for the first time. Antibacterial activity assay showed that compound 4 had inhibitory effect on Ralstonia solanacearum.
Anisoles ; chemistry ; isolation & purification ; pharmacology ; Anti-Bacterial Agents ; chemistry ; isolation & purification ; pharmacology ; Benzophenones ; chemistry ; isolation & purification ; pharmacology ; Chromatography ; methods ; Dalbergia ; chemistry ; Dextrans ; Gels ; Isoflavones ; chemistry ; isolation & purification ; pharmacology ; Microbial Sensitivity Tests ; Naphthalenes ; chemistry ; isolation & purification ; pharmacology ; Plant Extracts ; chemistry ; isolation & purification ; pharmacology ; Pterocarpans ; chemistry ; isolation & purification ; pharmacology ; Ralstonia solanacearum ; drug effects ; growth & development ; Silica Gel

PURPOSE: There has not been any reports of Ralstonia paucula causing any ophthalmologic disease. However, we have detected Ralstonia paucula in the lens washing agents of a corneal ulcer patient wearing contact lens. METHODS: A 26-years-old female patient was admitted to our hospital complaining of loss of visual acuity and hyperemia. Slit lamp biomicroscopy and smear culture was done to the anterior segment of the eye and the lens cleansing agent. The patient was treated with antibiotic eye drop and intravenous antibiotic medication. RESULTS: The results of both smear and culture showed the presence of Ralstonia pacula and responded well to antibiotics treatment with ceftazidime.
Anti-Bacterial Agents ; Ceftazidime ; Corneal Ulcer* ; Detergents ; Female ; Humans ; Hyperemia ; Ralstonia* ; Visual Acuity

In this study, fosmid cloning strategies were used to assess the microbial populations in water from the International Space Station (ISS) drinking water system (henceforth referred to as Prebiocide and Tank A water samples). The goals of this study were: to compare the sensitivity of the fosmid cloning strategy with that of traditional culture-based and 16S rRNA-based approaches and to detect the widest possible spectrum of microbial populations during the water purification process. Initially, microbes could not be cultivated, and conventional PCR failed to amplify 16S rDNA fragments from these low biomass samples. Therefore, randomly primed rolling-circle amplification was used to amplify any DNA that might be present in the samples, followed by size selection by using pulsed-field gel electrophoresis. The amplified high-molecular-weight DNA from both samples was cloned into fosmid vectors. Several hundred clones were randomly selected for sequencing, followed by Blastn/Blastx searches. Sequences encoding specific genes from Burkholderia, a species abundant in the soil and groundwater, were found in both samples. Bradyrhizobium and Mesorhizobium, which belong to rhizobia, a large community of nitrogen fixers often found in association with plant roots, were present in the Prebiocide samples. Ralstonia, which is prevalent in soils with a high heavy metal content, was detected in the Tank A samples. The detection of many unidentified sequences suggests the presence of potentially novel microbial fingerprints. The bacterial diversity detected in this pilot study using a fosmid vector approach was higher than that detected by conventional 16S rRNA gene sequencing.
Biomass ; Bradyrhizobium ; Burkholderia ; Clone Cells ; Cloning, Organism ; Dermatoglyphics ; DNA ; DNA, Ribosomal ; Drinking ; Drinking Water ; Electrophoresis, Gel, Pulsed-Field ; Genes, rRNA ; Groundwater ; Mesorhizobium ; Nitrogen ; Pilot Projects ; Plant Roots ; Polymerase Chain Reaction ; Ralstonia ; Soil ; Water ; Water Purification