Thoracic spine infection caused by Pseudomonas fluorescens:A case report and review of literature

BACKGROUND The clinical incidence of spinal infection is gradually increasing,and its onset is insidious,easily leading to missed diagnosis and misdiagnosis,which may lead to serious complications such as nervous system dysfunction,spinal instability and/or deformity,and cause a huge burden on society and families.Early identification of the causative agent and precision medicine will greatly reduce the suffering of patients.At present,the main pathogenic bacteria that cause spinal infection are Staphylococcus aureus,Streptococcus,Pneumococcus,Escherichia coli,and Klebsiella.There are no reports of spinal infection caused by Pseudomonas fluorescens.CASE SUMMARY We report a 32-year-old female patient with spinal infection.She presented with flank pain,initially thought to be bone metastases or bone tuberculosis,and had a family background of tumors.Her clinical features and changes in imaging and laboratory tests led to the suspicion of thoracic spine infection.Histopathology of the lesion showed inflammation,tissue culture of the lesion was negative several times,and the possible pathogen-Pseudomonas fluorescens was found after gene sequencing of the lesion.The patient recovered completely after a full course of antibiotic treatment.CONCLUSION This report increases the range of pathogens involved in spinal infections,highlights the unique advantages of gene sequencing technology in difficult-todiagnose diseases,and validates conservative treatment with a full course of antibiotics for spinal infections without complications.

Bacteremia or pseudobacteremia?Review of pseudomonas fluorescens infections

INTRODUCTION P.fluorescens is an aerobic,Gram-negative bacillus related to Pseudomonas aeruginosa.Like other species of Pseudomonas,the organism is widespread in nature and is found in water,moist soil,and vegetation.Due to its low virulence,P.fluorescens is an infrequent cause of infections except for catheter-related bloodstream infections in cancer patients.From August 1,2003 to May 31,2016,Hyogo Emergency Medical Center and the Kobe Red Cross Hospital treated three cases of bloodstream infection

Improvement of Bio-Efficacy to Reduce Bacterial Wilt Complex Disease in Tomatoes through Bacillus amyloliquefaciens and Pseudomonas fluorescens under Field Conditions

Bacterial wilt complex disease of tomato(Solanum lycopersicum L.)was incited jointly by bacterial wilt pathogen Ralstonia solanacearum and Meloidogyne incognita worldwide.Bio-efficacy of bacterial antagonists i.e.B.amyloliquefaciens DSBA-11 and P.fluorescens DTPF-3 was studied against the wilt disease complex in tomato at National Phytotran facility Indian Agricultural Research Institute(IARI),New Delhi,at 26±2°C.Minimum wilt disease incidence(26.00%)with the highest bio-control efficacy(64.15%),less juvenile population(19.33 J2/g of soil)of M.incognita was recorded in the combined application of DTPF-3+DSBA-11 after 30 d of inoculation under glasshouse conditions.In a field study,minimum bacterial wilt disease incidences 19.0%and 20.4%were recorded in the bleaching powder treatment followed by mixed application of DSBA-11+DTPF-3,19.6%and 21.2%wilt incidence in 2014 and 2015 respectively.However,a reduction of root-knot gall index was recorded a maximum of 59.76%and 69.62%in DSBA-11+DTPF-3 treated plants followed by 54.88%and 60.13%over control in DTPF-3 treatment in 2014 and 2015 respectively.The yield of tomato fruit was increased over control by 17.48%and 16.97%in 2014 and 2015 respectively under field conditions.A combination of P.fluorescens DTPF-3+B.amyloliquefaciens DSBA-11 suppressed bacterial wilt and root-knot diseases and also increased the yield of the tomato fruit significantly(p<0.05)under field conditions.

Penetration and Post-infection Development of Meloidogyne Incognita on Tobacco as Treated by Rhizobacteria Pseudomonas Fluorescens Strain P-72-10

The bio-control potential of rhizospere bacteria Pseudomonas fluorescens against plant-parasite nematode had been demonstrated. P. fluorescens had shown the effect to enhance tobacco resistance to root-knot nematode Meloidogyne incognita. Inoculation with P. fluorescens in tobacco could lead to significant reductions in the number of juveniles that penetrated tobacco root and further life stage development of the juveniles. The number of juveniles penetrated into tobacco root in treatment with P. fluorescens is significantly different from CK at 2DAI,6DAI,8DAI and 10 DAI. Significant reduction and delayed development of juveniles that penetrated into tobacco root and treated were observed in treatment at14 DAI,21DAI,28 DAI and 35 DAI. In addition,P. fluorescens treatment leads to a significant reduction in the number of eggs per egg-mass at 35 DAI. The results show P. fluorescens induced a continuously suppression on root-knot nematode M. incognita throughout their entire early infection phase of root penetration,subsequent life stage development and reproduction.

Biosorption of cesium(Ⅰ) from aqueous solution by a novel exopolymers secreted from Pseudomonas fluorescens C-2: Equilibrium and kinetic studies

The biosorption characteristics of Cs（I） ions from aqueous solution using exopolymers （PFC02） produced from Pseudomonas fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and initial concentration. pH played a major role in the adsorption process, and the optimum pH for the removal of Cs（I） was 8.0. Langmuir, Freundlich and Dubinin-Radushkevich （D-R） models were applied to describe the biosorption isotherm of the Cs（I） ions by PFC02. The Lagergren first-order, pseudo second-order kinetic and intraparticle diffusion models were used to test the kinetic data. Langmuir model and D-R model fitted the equilibrium data better than the Freundlich isotherm. The monolayer adsorption capacities of PFC02 as obtained from Langmuir isotherm at 25°C was found to be 32.63 mg/g. From the D-R isotherm model, the mean free energy was calculated as 26.73 kJ/mol, indicating that the biosorption of cesium was chemisorption. The biosorption process was rapid, and the kinetic rates were best fitted to the pseudo second-order model, which indicated the biosorption process operated through chemisorption mechanism. FT-IR analysis of PFC02 showed the possible functional groups responsible for cesium adsorption were hydroxyl, carboxyl, carbonyl and sulphonate groups. SEM analysis showed the porous structure of the material while EDX analysis confirmed the adsorption of Cs（I） on PFC02. Cesium adsorbed onto the PFC02 could be desorbed efficiently using 1 mol/L HNO 3 , and the enrichment factor was 50.0. Furthermore, PFC02 could be reused five times with only about 8.25% regeneration loss. The developed method was successfully utilized for the removal of Cs（I） ions from aqueous solution.

一株草鱼源荧光假单胞菌的分离鉴定及其耐药特性分析

为探究临沂市某草鱼养殖场发生病害的原因,从患病的草鱼(Ctenopharyngodon idellus)肝脏和肾脏混合组织中分离得到一株优势致病菌G-13,通过细菌形态学观察、革兰氏染色、生理生化特征、16S rRNA基因测序,以及系统发育分析等完成菌株鉴定,并测定其耐药特性。形态特征显示G-13是一种短杆状的革兰氏阴性菌,在LB固体平板上形成乳白色、圆形、整体呈隆起状、边缘较为整齐、表面光滑湿润的菌落;16S rRNA系统发育进化分析发现G-13与荧光假单胞菌(Pseudomonas fluorescens)聚在一支,序列同源性高达100%;生理生化试验显示葡萄糖、精氨酸双水解酶、鸟氨酸脱羧酶、赖氨酸脱羧酶、氧化酶、无盐和3%NaCl胰胨水等7项指标为阳性,与假单胞菌属特征相近,确定分离株G-13为P.fluorescens。药敏试验结果显示菌株G-13对丁胺卡那、多西环素、四环素、新霉素、环丙沙星、氧氟沙星等13种抗生素敏感,对氨苄西林、头孢拉定、克林霉素、呋喃唑酮等7种抗生素耐药。

Rhizosphere Bacteria for Biocontrol of Bacterial Blight and Growth Promotion of Rice

Several bacterial strains were isolated from different rhizospheres. Among these, strain PDY7 exhibited strong antibacterial activity against the rice bacterial blight （BB） pathogen Xanthomonas oryzae pv. oryzae （Xoo） by the laboratory dual plate assays. The antibacterial property of the strain PDY7 was further investigated for the production of 2,4-diacetylphloroglucinol （DAPG）, which amplified a characteristic of 629-bp DNA fragment by PCR-based screening method using phlD primers. The application of phlD positive strains was carefully evaluated for disease control and growth promotion of rice plants under field conditions. The selected strain PDY7 suppressed the rice BB by 58.83% and 51.88% under glass house and field conditions, respectively. In addition, the strain PDY7 showed significant two-fold increase in root length （18.08 cm）, shoot length （29.81 cm）, and grain yield （96.07 g）. Strain PDY7 promoted the growth of rice plants by production of indole-3-acetic acid （IAA）, which was determined by high performance liquid chromatography （HPLC） analysis. Our findings suggest that PDY7 belongs to the P. fluorescens group and can serve as potential biocontrol of BB as well as biofertilizer agent for growth promotion of rice.

水蛭来源荧光假单胞菌的分离鉴定及系统发育树分析

为调查山东某水蛭养殖场病情暴发原因,从该场患病水蛭中分离得到优势菌株SZ-1,对其进行生理生化特性及分子生物学分析。形态学、生理生化分析显示,菌株SZ-1为革兰氏阴性菌,杆状,两端钝圆,有鞭毛;Biolog GenIII分析表明,该菌株生长代谢利用情况与假单胞菌属吻合,与荧光假单胞菌B特征相似。基于16S rRNA基因序列分析同源性,该菌株16S rRNA基因序列与荧光假单胞菌(Pseudomonas fluorescens)相聚类,聚合置信度可达99%。综合生物学及分子特征,判定SZ-1为荧光假单胞菌。

大蒜提取物对荧光假单胞菌生物膜形成的抑制作用

研究大蒜提取物对荧光假单胞菌(Pseudomonas fluorescens)生物膜形成的抑制作用。用结晶紫染色法以及光学显微镜对该菌产生的生物膜进行了研究,苯酚硫酸法测定其胞外多糖的产量,采用多孔板法研究了大蒜提取物与山梨酸钾的协同作用。结果表明,大蒜提取物浓度为100、150 mg/mL时,对生物膜的抑制率分别为27.6%和38.7%;对胞外多糖抑制率分别为4.5%和12.6%;100 mg/mL的提取物与山梨酸钾具有协同作用。因此,大蒜提取物对荧光假单胞菌生物膜的形成具有抑制作用。

Cell Surface Determinants Important for Biofilm-Based Solid Substrate Degradation

The study links targeted cell surface characterization to the quantified capacity of cellulose degrading Pseudomonas fluorescens cells to colonize a (similarly characterized) cellulosic carrier. The experiments were conducted to clarify the effect of cultivation conditions on the achieved state of this carrier colonization. The suggested approach seems to be sufficient to verify the right choice of cultivation medium as a major factor determining the binding complementarity between microbial cells and solid cellulose.

Characterization of 1-Aminocyclopropane-1-Carboxylate(ACC) Deaminase-Containing Pseudomonas spp.in the Rhizosphere of Salt-Stressed Canola

When exposed to biotic or abiotic stress conditions, plants produce ethylene from its immediate precursor 1-aminocyclopropane-1- carboxylate （ACC）, leading to retarded root growth and senescence. Many plant growth-promoting rhizobacteria contain the enzyme ACC deaminase and this enzyme can cleave ACC to form a-ketobutyrate and ammonium, thereby lowering levels of ethylene. The aim of this study was to isolate and characterize ACC deaminase-producing bacteria from the rhizosphere of salt-stressed canola （Brassica napus L.）. Out of 105 random bacterial isolates, 15 were able to utilize ACC as the sole source of nitrogen. These 15 isolates were also positive for indole acetic acid （IAA） production. Phylogenetic analysis based on partial 16S rDNA sequences showed that all isolates belonged to fluorescent Pseudomonas spp. In the canola rhizosphere investigated in this study, Pseudomonas fluorescens was the dominant ACC deaminase-producing species. Cluster analysis based on BOX-AIR-based repetitive extragenic palindromic-polymerase chain reaction （BOX-PCR） patterns suggested a high degree of genetic variability in ACC deaminase-producing P. fluorescens strains. The presence of indigenous ACC-degrading bacteria in the rhizosphere of canola grown in saline soils indicates that these bacteria may contribute to salinity tolerance.

Isolation and Identification of Phosphobacteria in PoplarRhizosphere from Different Regions of China

A few soil microorganisms can convert insoluble forms of phosphorus （P） to an accessible form to increase plant yields The objectives of this study were to isolate, screen and identify the phosphobacteria, i.e., phosphate-solubilizing bacteria （PSB） and phosphate-mineralizing bacteria （PMB）, in some poplar plantations and to select potential microbial inoculants that could increase the P uptake by plants. Seventy four PSB strains and 138 PMB strains were preliminarily screened from 797＂colonies isolated from the rhizosphere soil of poplar by the visible decolorization in the National Botanical Research Institute＇s phosphate growth medium （NBRIP） containing a pH indicator of bromophenol and by the clear/halo zone on yeast malt agar plate, respectively. Then, based on the solubilization of Ca3（PO4）2 in liquid NBRIP medium and the mineralization of lecithin in liquid Menkina medium, 15 PS1R strains and 7 PMB strains were further determined for their abilities to solubilize Ca3（PO4）2 and to mineralize lecithin. The results showed that the 15 PSB strains exhibited inorganic P-solubilizing abilities ranging between 376.62 and 669.56 mg L-1 and the 7 PMB strains exhibited organic P-mineralizing abilities vaxying from 0.32 to 1.56 mg L-1 three days after incubation. Three of PSB strains with the highest P-solubilizing ability, named JW-JS1, JW-JS2 and JW-SX2, were all preliminarily identified as Pseudomonas ftuorescens, while two of PMB strains with the highest P-mineralizing ability, named JYZ-SD1 and JYT-JS2, were preliminarily identified as Bacillus cereus and Bacillus subtilis, respectively. All the efficient PSB and PMB strains should be further studied under both pot culture and field conditions to test their beneficial effects on poplar.

Bacterial microcosms obey Taylor’s law:effects of abiotic and biotic stress and genetics on mean and variance of population density

Introduction:According to the empirical regularity called Taylor’s law,the variance of population density in samples of populations is a power of the mean population density.The exponent is often between 1 and 2.Our experiments investigated how genetics,evolution,and environment shape Taylor’s law.Methods:Genetically different strains(wild type and hypermutator)of the bacterium Pseudomonas fluorescens evolved and were assayed under different environmental conditions(with and without antibiotic rifampicin and bacteriophage SBW25
2,separately and in combination).Results:Experimental treatments altered the exponent b,but not the power law form,of the relation between variance and mean population density.Bacterial populations treated only with rifampicin had a narrow range of mean population densities and exponent b=5.43.Populations exposed to rifampicin plus phage had b=1.51.In ancestral,control,and phage-exposed populations,mean abundance varied widely and b was not significantly different from 2.Evolutionary factors(mutation rate,selection)and ecological factors(abiotic,biotic)jointly influenced b.Conclusions:Taylor’s power law relationship accurately and robustly described variance as a function of mean population density,with overall exponent b=1.89.These and other experiments with different factors acting on bacterial population size support the relevance of models that predict‘universal’patterns of fluctuation scaling.

The structure of natural microbial enemy-victim networks

Introduction:The persistence of generalists and specialists is a topical question in community ecology and results from both ecological and evolutionary processes.At fine taxonomical scales,ecological specialisation,i.e.organisms preferentially exploiting a subset of available habitats,is thought to be a driver promoting niche diversity.It is not clear,however,how different mechanisms interact to shape specialist-generalist coexistence.Methods:We reconstruct the structure of five bacteria-phage networks from soil isolates,and perform an analysis of the relationships between host phylogenetic diversity,parasite specialism,and parasite performance.Results:We show that the co-occurrence of species on a continuum of specialism/generalism is influenced by niche overlap,phage impact on bacterial hosts,and host phylogenetic structure.In addition,using a null-model analysis we show that infection strategies of the phages have more explanatory power than bacterial defenses on key structural features of these antagonistic communities.Conclusions:We report that generalists have more impact on their hosts than specialists,even when the phylogenetic heterogeneity of hosts is controlled for.We discuss our results in the light of their implications for the evolution of biotic interactions.

Benzaldehyde lyase-catalyzed enantioselective C-C bond formation and cleavage:A review

Benzaldehyde lyase(BAL)is an enzyme which was originally found from Pseudomonas fluorescens biovar I.It has long been used in the formation of a C-C bond.BAL can exclusively yield(R)-enantioselective products from the synthesis ofα-hydroxy ketones and has so far been explored as an important enzyme to prepare the corresponding intermediate of pharmaceuticals.Due to its substrate spectrum and stereospecificity,this enzyme extends the synthetic potential for carboligations appreciably.In this review,we highlight the biotransformation applications of BAL in recent years,some of which have achieved intriguing results and provided the theoretical basis for drug development and industrial purpose in the future.