PURPOSE: To report a case of a Comamonas acidovarans corneal ulcer treated with antibiotics in Korea. Comamonas acidovarans corneal ulcer has not been previously reported to our knowledge. METHODS: A 70-year-old woman visited our clinic complaining of left ocular pain and decreased visual acuity for six days. We performed a smear and culture on the corneal lesion and treated it with topical and systemic antibiotics. RESULTS: Comamonas acidovorans was cultured from ulcer lesion. Corneal ulcer improved with the administration of ciprofloxacin and tobramycin.
Aged ; Anti-Bacterial Agents ; Ciprofloxacin ; Comamonas* ; Corneal Ulcer* ; Delftia acidovorans* ; Female ; Humans ; Korea ; Tobramycin ; Ulcer ; Visual Acuity

To date, only one case of peritonitis with exit site infection in peritoneal dialysis caused by this micro- organism has been reported. In spite of its apparently benign clinical course, which distinguished it from peritonitis caused by Pseudomonas, this peritonitis relapsed and Comamonas could not be eliminated from the peritoneal liquid, probably due to the persistence of the micro-organism in the exit site. Consequently, peritoneal catheter was removed. In this case, a 68-year-old man was admitted with fever, abdominal tenderness and cloudy peritoneal effluent and empirically treated with antibiotics(cefazolin, tobramycin), intraperitoneally(IP) for 7 days. The first culture was positive for Comamonas acidovorans, sensitive to ceftazidime, cefotetan, ceftriaxone, ciprofloxaxin and imipenem and the perotoneal effluent remained cloudy after 7 days. He was treated with ceftazidime IP, oral ciprofloxacin and nystatin for 26 days. 4 days after the antibiotics treatment, the patient was asymptomatic and the cell count of peritoneal effluent was 50 WBC/mm3 with negative culture. 25 days after the treatment, the patient remained asymptomatic and with 5 WBC/mm3 in peritoneal effluent. Consequently, We experienced a case of peritonitis due to Comamonas acidovorans in a patient on CAPD without exit site infection and managed with preservation of the catheter.
Aged ; Anti-Bacterial Agents ; Catheters* ; Cefotetan ; Ceftazidime ; Ceftriaxone ; Cell Count ; Ciprofloxacin ; Comamonas* ; Delftia acidovorans* ; Fever ; Humans ; Imipenem ; Nystatin ; Peritoneal Dialysis ; Peritoneal Dialysis, Continuous Ambulatory* ; Peritonitis* ; Pseudomonas

Dissimilatory Metal Reduction Bacteria play an important role in the anaerobic environment. This kind of bacteria gains energy by coupling the oxidation of organic acid or sugars to the reduction of metal oxides. The graphite electrode rode can also be used as the final electron acceptor due to its similarity to solid metal oxides. Based on this biological mechanism, Dissimilatory Metal Reduction Bacteria Rhodoferaxferrireducens was used to construct a suit of microbial fuel cells with sugars as fuel, and the process and mechanism of electricity generation was studied. Rhodoferax ferrireducens was inoculated into the anode chamber in which a graphite electrode served as the final electron acceptor and glucose as the sole electron donor. It was showed that current density was up to 158mA/m2 with the resistance of 510omega at the normal temperature (platform voltage was around 0.46V, the effectual electrode surface was 57cm2). Following 20days' growth a large amount of bacteria cells attached to the electrode surface had been observed through the SEM images. The plandtonic cell protein concentration was 140mg/L and the attached biomass of electrode surface was 1180mg/m2 determined by the Bradford method, which indicated quite a few bacteria attached to the electrode. By analyzing the voltage value measured by the data acquisition system, it was proved that microbial electricity generation attributed mainly to the electrochemically and biologically active cells attached to the electrode, while the planktonic cells had no ability to catalyze electricity generation and almost had not electrochemically and biologically active. Furthermore, this kind of microbial fuel cells exhibited a good electrochemical cycle property and proved to be efficient in biomass utilization and energy restore since other sugars like fructose, sucrose, even xylose, could be oxidized and finally decomposed. Vast waste biomass in the form of carbohydrates is discarded in the environment. Not only is contamination of the environment caused by the discarded biomass, but also abundant energy stored in the biomass is drained away in vain. The sugar-based microbial fuel cells constructed by Rhodoferax ferrireducens could effectively transform the energy stored in sugars into electricity. Meanwhile, the microbial fuel cells presented in this paper, which could work cleanly at normal temperature with a good cycle property, showed a promising future application in this field.
Bioelectric Energy Sources ; microbiology ; Comamonadaceae ; metabolism ; Electricity ; Electron Transport ; Equipment Failure ; Glucose ; metabolism ; Oxidation-Reduction

Cytochrome P450 monooxygenases as powerful biocatalysts catalyze a wide range of chemical reactions to facilitate exogenous substances metabolism and biosynthesis of natural products. In order to explore new catalytic reactions and increase the number of P450 biocatalysts used in synthetic biology, a new self-sufficient cytochrome P450 monooxygenase (P450(VpMO)), belongs to CYP116B class, was mined from Variovorax paradoxus S110 genome and expressed in Escherichia coli. Based on characterization of the enzymatic properties, it shows that the optimal pH and temperature for P450(VpMO) reaction activity are 8.0 and 45 °C, respectively. P450(VpMO) is relatively stable at temperatures below 35 °C. The Km and kcat of P450(VpMO) toward 4-Methoxyacetophenone are 0.458 mmol/L and 2.438 min⁻¹, respectively. Importantly, P450(VpMO) was able to catalyze the demethylation reaction for a range of substrates containing methoxy group. Its demethylation reactivity is reasonably better than other P450s belongs to CYP116B class, particularly, for 4-methoxyacetophenone with a great conversion efficiency at 91%, showing that P450(VpMO) could be used as a great biocatalyst candidate for further analysis.
Catalysis ; Comamonadaceae ; enzymology ; genetics ; Cytochrome P-450 Enzyme System ; genetics ; metabolism ; Gene Expression ; Synthetic Biology

Delftia acidovorans is a gram-negative motile rod found ubiquitously in soil and in water. Confirmed isolation from clinical infections is rare, and has been documented mostly in immunocompromised patients or those with indwelling catheters. A 53-year-old man was referred for the evaluation of a huge mass-like lesion found incidentally by chest X-ray. The lesion occupied more than half of the right lung and was diagnosed as a large loculated pleural effusion by CT scan. Bloody pus was drained through a percutaneous catheter, and D. acidovorans, identified by the Vitek GN card and confirmed by amplification of 16S ribosomal RNA and sequencing analysis, was isolated repeatedly from the drained pus. The patient was treated with imipenem/cilastatin to which the organism was sensitive. This is a rare report of chronic empyema associated with D. acidovorans in the respiratory system of an immunocompetent patient.
Catheters ; Catheters, Indwelling ; Delftia ; Delftia acidovorans ; Drainage ; Empyema ; Empyema, Pleural ; Humans ; Immunocompetence ; Immunocompromised Host ; Lung ; Middle Aged ; Pleural Effusion ; Respiratory System ; RNA, Ribosomal, 16S ; Soil ; Suppuration ; Thorax

Delftia acidovarans is aerobic, nonfermentative Gram-negative rod commonly found in soil and water. Generally it is nonpathogenic but it unusually can cause bacteremia in immunocompromised patients. We present a case of peritonitis due to D. acidovorans in a patient on continuous ambulatory peritoneal dialysis. A 75-year-old woman was admitted with abdominal pain and cloudy peritoneal effluent. She was empirically treated with intraperitoneal (IP) cefazolin and ceftazidime, and then IP ceftazidime and oral ciprofloxacin, but peritonitis did not improve. Seven days after admission, D. acidovorans was identified from the peritoneal effluent, which was sensitive to amikacin, ceftazidime, ciprofloxacin and imipenem. Catheter removal was considered with regard to poor response to adequate antibiotics; however, 4 days after changing to IP imipenem/cilastatin, abdominal pain, the leukocyte count of peritoneal effluent and C-reactive protein decreased. She was treated with imipenem/cilastatin for two weeks and discharged with the dialysis catheter intact.
Abdominal Pain ; Aged ; Amikacin ; Bacteremia ; C-Reactive Protein ; Catheters ; Cefazolin ; Ceftazidime ; Ciprofloxacin ; Delftia ; Delftia acidovorans ; Dialysis ; Female ; Humans ; Imipenem ; Immunocompromised Host ; Leukocyte Count ; Peritoneal Dialysis ; Peritoneal Dialysis, Continuous Ambulatory ; Peritonitis ; Soil

Delftia acidovorans (earlier known as Comamonas acidovorans) is an aerobic, non-fermentative, Gram negative rod, classified in the Pseudomonas rRNA homology Group III. Reports of isolation of the organism from serious infections like central venous catheter associated bacteremia, corneal ulcers, otitis media exist. The microbiologists can identify this organism based on an orange indole reaction. This reaction demonstrates the organism's ability to produce anthranilic acid from tryptophan on addition of Kovac's reagent; which gives the media its characteristic "pumpkin orange" colour. Here we report the isolation of this organism from the Endotracheal tube aspirate of a 4 year old child. With the increasing use of invasive devices, it has become important to recognize these non fermentative gram negative bacilli as emerging source of infection even in immunocompetent individuals.
Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Child, Preschool ; Delftia acidovorans ; Drug Resistance, Bacterial ; Empyema ; Fatal Outcome ; Gram-Negative Bacterial Infections ; Humans ; Shock, Septic

PURPOSE: To report 2 cases of Comamonas acidovorans keratitis in immunocompromised cornea. METHODS: A complete review of the medical records of the two cases of Comamonas acidovorans keratitis. RESULTS: We found some similarities in clinical courses of two cases. Both of them showed development of keratitis during the management with corticosteroids, delayed onset, slow response to antibiotics, and relatively less affected corneal epithelium. CONCLUSIONS: Comamonas acidovorans is known as a less virulent organism. However it can cause an indolent infection that responds slowly even to adequate antibiotics therapy in immunocompromised corneas.
Amikacin/therapeutic use ; Anti-Bacterial Agents/therapeutic use ; Ceftazidime/therapeutic use ; Ciprofloxacin/therapeutic use ; Corneal Ulcer/diagnosis/drug therapy/*microbiology ; Delftia acidovorans/*isolation & purification ; Drug Therapy, Combination ; Eye Infections, Bacterial/diagnosis/drug therapy/*microbiology ; Gram-Negative Bacterial Infections/diagnosis/drug therapy/*microbiology ; Humans ; *Immunocompromised Host ; Male ; Microbial Sensitivity Tests ; Middle Aged

PURPOSE: To report 2 cases of Comamonas acidovorans keratitis in immunocompromised cornea. METHODS: A complete review of the medical records of the two cases of Comamonas acidovorans keratitis. RESULTS: We found some similarities in clinical courses of two cases. Both of them showed development of keratitis during the management with corticosteroids, delayed onset, slow response to antibiotics, and relatively less affected corneal epithelium. CONCLUSIONS: Comamonas acidovorans is known as a less virulent organism. However it can cause an indolent infection that responds slowly even to adequate antibiotics therapy in immunocompromised corneas.
Amikacin/therapeutic use ; Anti-Bacterial Agents/therapeutic use ; Ceftazidime/therapeutic use ; Ciprofloxacin/therapeutic use ; Corneal Ulcer/diagnosis/drug therapy/*microbiology ; Delftia acidovorans/*isolation & purification ; Drug Therapy, Combination ; Eye Infections, Bacterial/diagnosis/drug therapy/*microbiology ; Gram-Negative Bacterial Infections/diagnosis/drug therapy/*microbiology ; Humans ; *Immunocompromised Host ; Male ; Microbial Sensitivity Tests ; Middle Aged

To investigate the degradation of polycyclic aromatic hydrocarbons (PAHs) and the changes of rhizosphere microorganisms in the rhizosphere soil of Leymus chinensis during the remediation of PAHs contaminated soil by Comamonas testosteroni (C.t)-assisted Leymus chinensis, we evaluated the removal of PAHs in the rhizosphere of Leymus chinensis using gas chromatography-mass spectrometry (GC-MS), analyzed the bacterial community and the diversity in Leymus chinensis rhizosphere soil by high-throughput sequencing technology, characterized the correlation among PAHs degradation and bacterial community components performing redundancy analysis (RDA) and network analysis, and predicted PAHs degradation potential via PICRUSt software in this paper. The degradation of PAHs in the rhizosphere of Leymus chinensis was promoted, the abundance and diversity of bacteria and the correlation among bacteria and PAHs were changed, and the degradation potential of PAHs in Leymus chinensis rhizosphere soil was enhanced in the later stage of phytoremediation (60-120 d) due to the incorporation of C.t. The accelerated degradation of three PAHs (Nap, Phe, BaP) was accompanied by the differ abundance and correlation of Proteobacteria (Sphingomonas, MND1, Nordella), Actinomycetes (Rubrobacter, Gaiella), Acidobacteria (RB41) and Bacteroides (Flavobacterium) affected by C.t. The results provide new insight into the microorganism choices for microbial assisted plant remediation of soil PAHs and the mechanisms of enhanced PAHs degradation via the combination of Comamonas testosteroni engineering bacteria and plants.
Biodegradation, Environmental ; Comamonas testosteroni/genetics* ; Polycyclic Aromatic Hydrocarbons/analysis* ; Rhizosphere ; Soil ; Soil Microbiology ; Soil Pollutants