Effects of Fe₃O₄ on the denitrification performance of Pseudomonas stutzeri / 生物工程学报

Biological denitrification is the most widely used technology for nitrate removal in wastewater treatment. Conventional denitrification requires long hydraulic retention time, and the nitrate removal efficiency in winter is low due to the low temperature. Therefore, it is expected to develop new approaches to enhance the denitrification process. In this paper, the effect of adding different concentrations of Fe₃O₄ nanoparticles on the denitrification catalyzed by Pseudomonas stutzeri was investigated. The maximum specific degradation rate of nitrate nitrogen improved from 18.0 h⁻¹ to 23.7 h⁻¹ when the concentration of Fe₃O₄ increased from 0 mg/L to 4 000 mg/L. Total proteins and intracellular iron content also increased along with increasing the concentration of Fe₃O₄. RT-qPCR and label-free proteomics analyses showed that the relative expression level of denitrifying genes napA, narJ, nirB, norR, nosZ of P. stutzeri increased by 55.7%, 24.9%, 24.5%, 36.5%, 120% upon addition of Fe₃O₄, and that of denitrifying reductase Nap, Nar, Nir, Nor, Nos increased by 85.0%, 147%, 16.5%, 47.1%, 95.9%, respectively. No significant difference was observed on the relative expression level of denitrifying genes and denitrifying reductases between the bacteria suspended and the bacteria adhered to Fe₃O₄. Interestingly, the relative expression level of electron transfer proteins of bacteria adhered to Fe₃O₄ was higher than that of the bacteria suspended. The results indicated that Fe₃O₄ promoted cell growth and metabolism through direct contact with bacteria, thereby improving the denitrification. These findings may provide theoretical support for the development of enhanced denitrification.

A propósito de un caso: Pseudomonas stutzeri, una causa inusual de artritis séptica / A Case Report: Pseudomonas Stutzeri, An Unusual Cause Of Septic Arthritis

RESUMEN Se presenta un caso de artritis séptica de rodilla por Pseudomonas stutzeri, bacilo gramnegativo aerobio ampliamente distribuido en la naturaleza y que rara vez ocasiona infecciones graves en el ser humano. Se trata de una mujer de 84 arios, hemodializada, que desarrolla una artritis séptica de rodilla derecha tras una inflitración con ácido hialurónico y que evoluciona favorablemente tras terapia antibiótica. Se debe tener en cuenta esta etiología cuando hay antecedentes de invasión local de la articulación y en estados de inmunosupresión tal y como sucede en nuestra paciente.

A B S T R A C T A case is presented of septic knee arthritis caused by Pseudomonas stutzeri, which is an aerobic gram-negative bacillus widely distributed in nature and rarely causes serious infections in humans. The patient is an 84-year-old woman on haemodialysis, who developed a septic arthritis of the right knee after a hyaluronic acid injection. There was a favourable outcome after antibiotic therapy. This aetiology should be taken into account when there is a history of local invasion of the joint and in states of immunosuppression, as occurred in this patient.

Simultaneous biodegradation of phenol and cyanide present in coke-oven effluent using immobilized Pseudomonas putida and Pseudomonas stutzeri

ABSTRACT Discharge of coke-oven wastewater to the environment may cause severe contamination to it and also threaten the flora and fauna, including human beings. Hence before dumping it is necessary to treat this dangerous effluent in order to minimize the damage to the environment. Conventional technologies have inherent drawbacks however, biological treatment is an advantageous alternative method. In the present study, bacteria were isolated from the soil collected from the sites contaminated by coke-oven effluent rich in phenol and cyanide. Nucleotides sequence alignment and phylogenetic analysis showed the identity of the selected phenol and cyanide degrading isolates NAUN-16 and NAUN-1B as Pseudomonas putida and Pseudomonas stutzeri, respectively. These two isolates tolerated phenol up to 1800 mg L-1 and cyanide up to 340 mg L-1 concentrations. The isolates were immobilized on activated charcoal, saw dust and fly ash. The effluent was passed through the column packed with immobilized cells with a flow rate of 5 mL min-1. The isolates showed degradation of phenol up to 80.5% and cyanide up to 80.6% and also had the ability to reduce biological oxygen demand, chemical oxygen demand and lower the pH of effluent from alkaline to near neutral. The study suggests the utilization of such potential bacterial strains in treating industrial effluent containing phenol and cyanide, before being thrown in any ecosystem.

Quiste odontogénico inflamatorio: aislamiento de Pseudomonas stutzeri. Relevancia diagnóstica / Isolation of Pseudomonas stutzeri from an odontogenic inflammatory cyst: Diagnostic relevance

Pseudomonas stutzeri se encuentra ampliamente distribuido en el medio ambiente, ocupando diversos nichos ecológicos; pero su aparición en procesos infecciosos de interés clínico es el de patógeno oportunista. El aislamiento de P. stutzeri en un quiste inflamatorio odontogénico es un verdadero hallazgo microbiológico que no presenta antecedentes en la bibliografía científica odontológica. En este caso particular, el aislamiento se obtuvo a partir de material quirúrgico proveniente de un quiste odontogénico inflamatorio ubicado en la pieza dentaria 1.2 con necrosis pulpar concomitante. Se emplearon técnicas diagnósticas complementarias como radiografías, tomografías, estudios anatomopatológicos y microbiológicos. Los resultados permitieron clasificar el proceso como quiste inflamatorio infectado con P. stutzeri. La tipificación y la caracterización del perfil de sensibilidad de la cepa aislada permitieron adecuar la terapéutica antibiótica de manera específica. El análisis microbiológico permitió establecer la etiología del proceso infeccioso, la adecuación del tratamiento y el restablecimiento de los tejidos comprometidos.

Pseudomonas stutzeri is distributed widely in the environment, and occupies different ecological niches. However, it is found in clinically relevant infections as an opportunistic pathogen. Isolation of P. stutzeri from an odontogenic inflammatory cyst is an uncommon microbiological finding that has not been reported to date. In the case presented here, the bacterium was isolated from surgical material obtained from excision of an inflammatory odontogenic cyst located in the tooth 1.2, and presenting with concomitant pulp necrosis. Complementary techniques such as radiographs, CAT scans, and histopathological and microbiological studies were used to establish definitive diagnosis. The obtained results allowed classifying the process as an inflammatory cyst infected by P. stutzeri. Biotyping and characterization of the susceptibility profile of the isolated strain allowed adjusting the antibiotic therapy more specifically. The microbiological studies allowed establishing the etiology of the infectious process, adjusting the treatment plan, and re-establishing tissue integrity.

Biodegradation of crude oil by individual bacterial strains and a mixed bacterial consortium

Three bacterial isolates identified as Alcanivorax borkumensis SK2, Rhodococcus erythropolis HS4 and Pseudomonas stutzeri SDM, based on 16S rRNA gene sequences, were isolated from crude oil enrichments of natural seawater. Single strains and four bacterial consortia designed by mixing the single bacterial cultures respectively in the following ratios: (Alcanivorax: Pseudomonas, 1:1), (Alcanivorax: Rhodococcus, 1:1), (Pseudomonas: Rhodococcus, 1:1), and (Alcanivorax: Pseudomonas: Rhodococcus, 1:1:1), were analyzed in order to evaluate their oil degrading capability. All experiments were carried out in microcosms systems containing seawater (with and without addition of inorganic nutrients) and crude oil (unique carbon source). Measures of total and live bacterial abundance, Card-FISH and quali-, quantitative analysis of hydrocarbons (GC-FID) were carried out in order to elucidate the co-operative action of mixed microbial populations in the process of biodegradation of crude oil. All data obtained confirmed the fundamental role of bacteria belonging to Alcanivorax genus in the degradation of linear hydrocarbons in oil polluted environments.

Biotransformation of Tributyltin chloride by Pseudomonas stutzeri strain DN2

A bacterial isolate capable of utilizing tributyltin chloride (TBTCl) as sole carbon source was isolated from estuarine sediments of west coast of India and identified as Pseudomonas stutzeri based on biochemical tests and Fatty acid methyl ester (FAME) analysis. This isolate was designated as strain DN2. Although this bacterial isolate could resist up to 3 mM TBTCl level, it showed maximum growth at 2 mM TBTCl in mineral salt medium (MSM). Pseudomonas stutzeri DN2 exposed to 2 mM TBTCl revealed significant alteration in cell morphology as elongation and shrinkage in cell size along with roughness of cell surface. FTIR and NMR analysis of TBTCl degradation product extracted using chloroform and purified using column chromatography clearly revealed biotransformation of TBTCl into Dibutyltin dichloride (DBTCl2) through debutylation process. Therefore, Pseudomonas stutzeri strain DN2 may be used as a potential bacterial strain for bioremediation of TBTCl contaminated aquatic environmental sites.

Successful antibiotic treatment of Pseudomonas stutzeri-induced peritonitis without peritoneal dialysis catheter removal in continuous ambulatory peritoneal dialysis

Pseudomonas stutzeri is a Gram-negative, rod-shaped, motile, single polar-flagellated, soil bacterium that was first isolated from human spinal fluid and is widely distributed in the environment. It was isolated as an uncommon opportunistic pathogen from humans, and a few cases of P. stutzeri-induced peritonitis have been reported in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Catheter removal with antibiotic treatment is generally recommended because peritonitis by Pseudomonas species is commonly associated with catheter-related infection. Here, we describe the first case of P. stutzeri-induced peritonitis in an 82-year-old woman in Korea. She had received two antipseudomonal antibiotics, an aminoglycoside (isepamicin, Yuhan corporation, Seoul, Korea) and a fluoroquinolone (ciprofloxacin), and was successfully treated without removal of the CAPD catheter.

Úlcera de córnea por Pseudomonas stutzeri / Pseudomonas stutzeri corneal ulcer

Este relato aborda um caso atípico de úlcera de córnea em uma criança de 09 anos, causado pela bactéria Pseudomonas stutzeri, um micro-organismo oportunista cujo isolamento em olhos é extremamente raro.

This report discusses an unusual case of corneal ulcer in a child of 09 years old, caused by the bacteria Pseudomonas stutzeri, an opportunistic organism whose isolation in the eyes is extremely rare.

Use of Pseudomonas stutzeri and Candida utilis in the improvement of the conditions of Artemia culture and protection against pathogens

To evaluate the effect of two bacterial strains isolated from Artemia cysts and yeast (Candida utilis) on the survival, growth and total biomass production of its larvae, challenge tests were performed with Candida utilis, Pseudomonas stutzeri and Pasteurella haemolityca. In addition, a pathogenic strain of Vibrio alginolyticus was tested for comparative purposes. Pseudomonas stutzeri and Candida utilis have no impact on survival, but enhance growth and total biomass production of the larvae. However, we noted that Pasteurella haemolityca affect negatively Artemia larvae. The adhesion and antagonism assay demonstrates that Candida utilis and Pseudomonas stutzeri are fairly adherent and play an important role in the enhancement of the protection of Artemia culture against pathogens. On the basis of these results, it's suggested that it's possible to use Candida utilis and Pseudomonas stutzeri, potential candidates, as probiotic for the culture of Artemia larvae.

Enhanced crude oil biodegradation and rhamnolipid production by Pseudomonas stutzeri strain G11 in the presence of Tween-80 and Triton X-100.

In this study, the growth of sixty-one bacterial strains in crude oil were determined spectrophotometrically at 620 nm. Pseudomonas aeruginosa G1, Pseudomonas fluorescens G6, Pseudomonas stutzeri G11 and Pseudomonas putida G15 were chosen for the study based on the efficiency of crude oil utilisation. At 1% (v/v) crude oil concentration, P. stutzeri G11 strain degraded a maximum of 69%. The percentage of degradation by the P. stutzeri G11 strain decreased from 69% to 59% as the concentration of crude oil was increased from 1% (v/v) to 2.5% (v/v). Strain G11 was selected to determine the effects of surfactants (Tween-80 and TritonX-100) on the biodegradation of crude oil. While strain G11 showed 76% degradation at mineral salts medium (MSM) containing 1% (v/v) crude oil + 1% (v/v) TritonX-100, it showed 61% degradation at MSM containing 2.5% (v/v) crude oil + 2.5% (v/v) TritonX-100. Also, degradation rate of this strain was 96% in the presence of 1% (v/v) crude oil + 1% (v/v) Tween-80, while degradation rate was 48% in the presence of 25% (v/v) crude oil+ 2.5% (v/v) Tween-80. Additionally, we investigated the rhamnolipid production of P. stutzeri G11 strain both in crude oil and in crude oil + two different surfactants (TritonX-100 and Tween-80, separately). These results suggest that surfactants have improved both crude oil degradation and rhamnolipid production and the degradation rates have depended very much on the chemical structure of surfactants.

[Comparison of ethanol, methanol and succinate effects as carbon sources on effluent biological denitrification]

Increase of nitrate concentration in water sources is becoming a serious problem in many parts of the world. Nitrogen containing compounds released into environment can create serious problems, such as eutrophication of water sources and hazard potential to human health, because it has potency of causing methemoglubinemia disease and cancer. Between recommended methods, biological denitrification is an effective method to remove nitrate from water and wastewater. In this study, biological nitrogen removal process was evaluated using ethanol, methanol and succinate as different organic carbon sources in batch scale. The different parameters, carbon source, initial nitrate concentration, pH, and inoculated of bacteria were evaluated. The experimental results were showed that bacteria can not use methanol as carbon source. The dinitrifyers bacteria can dissimilate 200 mg/L No3-N, in the optimum condition: 28 °C, pH 7.2 and initial inoculation of 3x 10[8] CFU/ml, respectively. In the process, produced nitrate-N was less than 1 mg/I. The bacterium Pseudomonas stuizeri can use ethanol as carbon source for biological denitrification, but efficiency of succinate was better than ethanol

Improvement of water quality through biological denitrification.

The present study was undertaken to observe the effect of biological denitrification process on water quality parameters. The results obtained in the present investigations show that the value of pH and alkalinity was increased due to generation of alkalinity during biological denitrification process. The obtained value of the DO in the treated water was found lower than the supplied water, which indicates, DO was consumed by the bacterium. The COD of the treated water was nil, which shows that the organics have been consumed by the bacterium during the denitrification process. The biological reduction of nitrate-nitrogen (from 50.79 mg/L to 0.57 mg/L) was found to be lower than the tolerance limit prescribed by WHO without changing the water quality.

The effect of carbon as an energy source for biological denitrification through Pseudomonas stutzeri.

The biological denitrification processes possess many advantages in comparison to other denitrification processes. The present study was undertaken to observe the effect of quantity of carbon on biological denitrification with Pseudomonas stutzeri at different C/N ratios. The results obtained in the present investigations show that the pH and alkalinity of the effluent increased with increase in C/N ratio due to alkalinity generated during denitrification. The COD of the influent was increased with increase in C/N ratio. The effluent COD was nil under pseudo-steady state condition up to the C/N ratio of 2.5. Above this C/N ratio, the organics started entering in the treated water. The maximum feasible economic reduction of NO(3-)N from 51.6 mg/l to 1.2 mg/l occurred at C/N ratio of 2.5 and the obtained concentration of NO(3-)N was found to be lower than the tolerance limit (10 mg/l) prescribed by the WHO. The present work provides a feasible approach for a more efficient NO(3-)N removal process.

A case of entrapped temporal horn of lateral ventricle caused by Pseudomonas stutzeri choroid plexitis

Focal ventricular dilatation of the temporal horn caused by an occlusion of the cerebrospinal fluid pathway at the atrium of the lateral ventricle is a form of non communicating hydrocephalus, and this condition is termed as "entrapment of the temporal horn". The choroid plexus is important central nervous system(CNS) structure, but it is often neglected in pathologic and clinical studies of intracranial diseases. Even though choroid plexitis is very rare, it may be occurred as the resultant of CNS infections and primary choroid plexitis can be associated with bacterial, viral, and parasitic etiologies. Some aspects of the neuroimaging findings of this infection mimick those of a intraventricular neoplasms. The most important neoplasms which should be differentiated, are choroid plexus papilloma and carcinoma. Wherem primary neoplasms of the choroid plexus are well known, but primary infections of the choroid plexus (such as choroid plexitis) are not commonly encountered. Pseudomonas stutzeri infections are especially rare as the causative organism of the choroid plexitis and often have serious underlying disease but generally respond well to treatment with antibiotics. We report a 65-year-old female patient with primary choroid plexitis due to Pseudomonas stutzeri and the findings of her brain computerized tomography and magnetic resonance imaging. In conclusion, our case revealed that choroid plexitis may result in ventricular entrapment and mimick intraventricular tumors. Although it is very rare, when a intraventricular mass was observed in imaging studies and combined with signs and symptoms suggesting CNS infection, choroid plexitis should be considered.