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Pediatric Infectious Disease 1985Pseudomonas fluorescens was recovered from 62 of 22,270 (0.26%) blood cultures, from 57 patients, over a 22-month period at a pediatric hospital. No illness was...
Pseudomonas fluorescens was recovered from 62 of 22,270 (0.26%) blood cultures, from 57 patients, over a 22-month period at a pediatric hospital. No illness was attributable to the blood culture isolate. A case-control study identified a significant correlation between the recovery of P. fluorescens in blood culture and concomitant coagulation studies (p less than 0.0001). In all cases blood for coagulation studies had been obtained at the same time as the blood culture. A review of venipuncture technique revealed that occasionally the coagulation study tubes (containing 3.8% sodium citrate) were being inoculated before blood culture bottles. P. fluorescens was subsequently isolated from coagulation tubes and from sodium citrate solutions prepared and dispensed in the hospital for use in coagulation studies. In vitro studies confirmed that sodium citrate solutions supported the growth of P. fluorescens, with preferential growth at 25 degrees C and 4 degrees C. This is the first description of P. fluorescens as a cause of pseudobacteremia. Pseudobacteremia was attributed to cross-contamination of blood cultures following inoculation of contaminated citrated collection tubes.
Topics: Adolescent; Adult; Blood; Child; Child, Preschool; Female; Humans; Infant; Infant, Newborn; Male; Microbiological Techniques; Pseudomonas Infections; Pseudomonas fluorescens; Sepsis
PubMed: 3931059
DOI: 10.1097/00006454-198509000-00014 -
Microbiological Research Jun 2021Microbial co-inoculation strategy utilizes a combination of microbes to stimulate plant growth concomitant with an increased phytopathogen tolerance. In the present...
Chickpea (Cicer arietinum L.) as model legume for decoding the co-existence of Pseudomonas fluorescens and Mesorhizobium sp. as bio-fertilizer under diverse agro-climatic zones.
Microbial co-inoculation strategy utilizes a combination of microbes to stimulate plant growth concomitant with an increased phytopathogen tolerance. In the present study, 15 endophytic bacterial isolates from rhizosphere and roots of wild chickpea accessions (Cicer pinnatifidum, C. judiacum, C. bijugum and C. reticulatum) were characterized for morphological, biochemical and physiological traits. Two promising isolates were identified as Pseudomonas fluorescens strain LRE-2 (KR303708.1) and Pseudomonas argentinensis LPGPR-1 (JX239745.1) based on 16S rRNA gene sequencing. Biocompatibility of selected endophytes with Mesorhizobium sp. CH1233, a standard isolate used as a national check in All India Coordinated Research Project (AICRP) was assessed to develop functional combinations capable of producing Indole acetic acid, gibberellins, siderophores and improving seed vigour (in vitro). In vivo synergistic effect of promising combinations was further evaluated under national AICRP, (Chickpea) at two different agro-climatic zones [North-West plain (Ludhiana and Hisar) and Central zones (Sehore)] for three consecutive Rabi seasons (2015-18) to elucidate their effect on symbiotic, soil quality and yield parameters. On the pooled mean basis across locations over the years, combination of Mrh+LRE-2 significantly enhanced symbiotic, soil quality traits and grain yield over Mrh alone and highly positive correlation was obtained between the nodulation traits and grain yield. Superior B: C ratio (1.12) and additional income of Rs 6,505.18 ha was obtained by application of Mrh+LRE-2 over Mrh alone and un-inoculated control. The results demonstrate that dual combination of Mrh and Pseudomonas sp. from wild Cicer relatives can be exploited as a potential bio-fertilizer for increasing soil fertility and improving chickpea productivity under sustainable agriculture.
Topics: Agriculture; Cicer; Endophytes; Fabaceae; Fertilizers; Indoleacetic Acids; Mesorhizobium; Phylogeny; Plant Development; Plant Roots; Pseudomonas; Pseudomonas fluorescens; RNA, Ribosomal, 16S; Rhizosphere; Seeds; Soil; Soil Microbiology; Symbiosis
PubMed: 33592359
DOI: 10.1016/j.micres.2021.126720 -
Canadian Journal of Microbiology Dec 1987In this study, the adhesive exopolysaccharides of strains of Pseudomonas putida and P. fluorescens, both isolated from freshwater epilithic communities, were examined... (Comparative Study)
Comparative Study
In this study, the adhesive exopolysaccharides of strains of Pseudomonas putida and P. fluorescens, both isolated from freshwater epilithic communities, were examined with regard to their chemical composition, biosynthesis, and their role in adhesion. Electron microscopy showed that both strains were enrobed in fibrous glycocalyces and that these structures were involved in attachment of the cells to a solid surface and as structural matrices in the microcolony mode of growth. In batch culture experiments most of the extracellular polysaccharide of both strains was found to be soluble in the growth medium rather than being associated with bacterial cells. Exopolysaccharide was synthesized during all phases of growth, but when growth was limited by exhaustion of the carbon source, exopolysaccharide synthesis ceased whereas exopolysaccharide synthesis continued for some time after cessation of growth in nitrogen-limited cultures. Exopolysaccharide from both strains was isolated and purified. Pseudomonas putida synthesized an exopolysaccharide composed of glucose, galactose, and pyruvate in a ratio of 1:1:1; the P. fluorescens polymer contained glucose, galactose, and pyruvate in a ratio of 1:1:0.5, respectively. Polymers from both strains were acetylated to a variable degree.
Topics: Carbohydrates; Kinetics; Microscopy, Electron; Polysaccharides, Bacterial; Pseudomonas; Pseudomonas fluorescens; Ruthenium Red; Species Specificity
PubMed: 2451553
DOI: 10.1139/m87-189 -
FEMS Microbiology Ecology Oct 2013Motility is an important trait for some bacteria living in nature and the analyses of it can provide important information on bacterial ecology. While the swimming...
Motility is an important trait for some bacteria living in nature and the analyses of it can provide important information on bacterial ecology. While the swimming behavior of peritrichous bacteria such as Escherichia coli has been extensively studied, the monotrichous bacteria such as the soil inhabiting and plant growth promoting bacterium Pseudmonas fluorescens is not very well characterized. Unlike E. coli that is propelled by a left-handed flagella bundle, P. fluorescens SBW25 swims several times faster by rotating a right-handed flagellum. Its swimming pattern is the most sophisticated known so far: it swims forward (run) and backward (backup); it can swiftly 'turn' the run directions or 'reorient' at run-backup transitions; it can 'flip' the cell body continuously or 'hover' in the milieu without translocation. The bacteria swam in circles near flat surfaces with reduced velocity and increased turn frequency. The viscous drag load due to wall effect potentially accounts for the circular motion and velocity change, but not the turn frequency. The flagellation and swimming behavior of P. fluorescens SBW25 show some similarity to Caulobacter, a fresh-water inhabitant, while the complex swimming pattern might be an adaptation to the geometrically restricted rhizo- and phyllospheres.
Topics: Flagella; Locomotion; Pseudomonas fluorescens; Viscosity
PubMed: 23346905
DOI: 10.1111/1574-6941.12076 -
Research in Microbiology Jun 2009Pseudomonas fluorescens is a highly heterogeneous species and includes both avirulent strains and clinical strains involved in nosocomial infections. We previously...
Pseudomonas fluorescens is a highly heterogeneous species and includes both avirulent strains and clinical strains involved in nosocomial infections. We previously demonstrated that clinical strain MFN1032 has hemolytic activity involving phospholipase C (PlcC) and biosurfactants (BSs), similar to that of the opportunistic pathogen Pseudomonas aeruginosa. When incubated under specific conditions, MFN1032 forms translucent phenotypic variant colonies defective in hemolysis, but not necessarily in PlcC. We analyzed eight variants of the original strain MFN1032 and found that they clustered into two groups. Mutations of genes encoding the two-component regulatory system GacS/GacA are responsible for phenotypic variation in the first group of variants. These group 1 variants did not produce secondary metabolites and had impaired biofilm formation. The second group was composed of hyperflagellated cells with enhanced biofilm capacity: they did not produce BSs and were thus unable to swarm. Artificial reduction of the intracellular level of c-di-GMP restored the ability to form biofilm to levels shown by the wild type, but production of BSs was still repressed. Phenotypic variation might increase the virulence potential of this strain.
Topics: Bacterial Proteins; Biofilms; Humans; Mutation; Phenotype; Pseudomonas Infections; Pseudomonas fluorescens; Surface-Active Agents; Transcription Factors
PubMed: 19409488
DOI: 10.1016/j.resmic.2009.04.004 -
Antonie Van Leeuwenhoek Sep 2014Although nitrosative stress is known to severely impede the ability of living systems to generate adenosine triphosphate (ATP) via oxidative phosphorylation, there is...
Although nitrosative stress is known to severely impede the ability of living systems to generate adenosine triphosphate (ATP) via oxidative phosphorylation, there is limited information on how microorganisms fulfill their energy needs in order to survive reactive nitrogen species (RNS). In this study we demonstrate an elaborate strategy involving substrate-level phosphorylation that enables the soil microbe Pseudomonas fluorescens to synthesize ATP in a defined medium with fumarate as the sole carbon source. The enhanced activities of such enzymes as phosphoenolpyruvate carboxylase and pyruvate phosphate dikinase coupled with the increased activities of phospho-transfer enzymes like adenylate kinase and nucleoside diphophate kinase provide an effective strategy to produce high energy nucleosides in an O2-independent manner. The alternate ATP producing machinery is fuelled by the precursors derived from fumarate with the aid of fumarase C and fumarate reductase. This metabolic reconfiguration is key to the survival of P. fluorescens and reveals potential targets against RNS-resistant organisms.
Topics: Adenosine Triphosphate; Carbon; Culture Media; Fumarates; Nitroso Compounds; Pseudomonas fluorescens
PubMed: 24923559
DOI: 10.1007/s10482-014-0211-7 -
Environmental Microbiology Apr 2010The GacS/GacA signal transduction system is a central regulator in Pseudomonas spp., including the biological control strain P. fluorescens Pf-5, in which GacS/GacA...
The GacS/GacA signal transduction system is a central regulator in Pseudomonas spp., including the biological control strain P. fluorescens Pf-5, in which GacS/GacA controls the production of secondary metabolites and exoenzymes that suppress plant pathogens. A whole genome oligonucleotide microarray was developed for Pf-5 and used to assess the global transcriptomic consequences of a gacA mutation in P. fluorescens Pf-5. In cultures at the transition from exponential to stationary growth phase, GacA significantly influenced transcript levels of 635 genes, representing more than 10% of the 6147 annotated genes in the Pf-5 genome. Transcripts of genes involved in the production of hydrogen cyanide, the antibiotic pyoluteorin and the extracellular protease AprA were at a low level in the gacA mutant, whereas those functioning in siderophore production and other aspects of iron homeostasis were significantly higher in the gacA mutant than in wild-type Pf-5. Notable effects of gacA inactivation were also observed in the transcription of genes encoding components of a type VI secretion system and cytochrome c oxidase subunits. Two novel gene clusters expressed under the control of gacA were identified from transcriptome analysis, and we propose global-regulator-based genome mining as an approach to decipher the secondary metabolome of Pseudomonas spp.
Topics: Bacterial Proteins; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Genome, Bacterial; Multigene Family; Mutation; Oligonucleotide Array Sequence Analysis; Pseudomonas fluorescens; RNA, Bacterial; Sequence Deletion
PubMed: 20089046
DOI: 10.1111/j.1462-2920.2009.02134.x -
Natural Product Communications Jun 2014An antibiotic substance isolated from Pseudomonas fluorescens strain G308 was earlier assigned the structure of N-mercapto-4-formylcarbostyril, but computational...
An antibiotic substance isolated from Pseudomonas fluorescens strain G308 was earlier assigned the structure of N-mercapto-4-formylcarbostyril, but computational predictions of the 1H and 13C NMR magnetic shielding tensors show this structure to be incompatible with the published spectroscopic data. The same is true for six quinoline derivatives related to N-mercapto-4-formylcarbostyril by permutation of the O and S atoms. In contrast, 2-(2-hydroxyphenyl)thiazole-4-carbaldehyde [aeruginaldehyde], isolated from Pseudomonas protegens Pf-5, together with the reduced derivative aeruginol, displays spectroscopic data identical with those of the alleged carbostyril derivative. In addition, the published 1H and 13C NMR data are in agreement with those calculated for aeruginaldehyde. We propose that aeruginaldehyde and aeruginol originate from the non-ribosomal peptide synthetase enzymes involved in the siderophores enantio-pyochelin (or pyochelin) biosynthetic pathways.
Topics: Computational Biology; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Molecular Structure; Phenols; Pseudomonas fluorescens; Quinolones; Sulfhydryl Compounds; Thiazoles
PubMed: 25115080
DOI: No ID Found -
BMC Microbiology Jul 2013The emergence of colony morphology variants in structured environments is being recognized as important to both niche specialization and stress tolerance. Pseudomonas...
BACKGROUND
The emergence of colony morphology variants in structured environments is being recognized as important to both niche specialization and stress tolerance. Pseudomonas fluorescens demonstrates diversity in both its natural environment, the rhizosphere, and in laboratory grown biofilms. Sub-populations of these variants within a biofilm have been suggested as important contributors to antimicrobial stress tolerance given their altered susceptibility to various agents. As such it is of interest to determine how these variants might be distributed in the biofilm environment.
RESULTS
Here we present an analysis of the spatial distribution of Pseudomonas fluorescens colony morphology variants in mixed-culture biofilms with the wildtype phenotype. These findings reveal that two variant colony morphotypes demonstrate a significant growth advantage over the wildtype morphotype in the biofilm environment. The two variant morphotypes out-grew the wildtype across the entire biofilm and this occurred within 24 h and was maintained through to 96 h. This competitive advantage was not observed in homogeneous broth culture.
CONCLUSIONS
The significant advantage that the variants demonstrate in biofilm colonization over the wildtype denotes the importance of this phenotype in structured environments.
Topics: Biofilms; Genetic Variation; Humans; Microbial Interactions; Pseudomonas fluorescens; Time Factors
PubMed: 23890016
DOI: 10.1186/1471-2180-13-175 -
Journal of Food Protection Oct 1998The relationship between bacterial growth and oxymyoglobin oxidation in vitro and in meat was studied. In the in vitro study, oxymyoglobin was combined with Pseudomonas...
The relationship between bacterial growth and oxymyoglobin oxidation in vitro and in meat was studied. In the in vitro study, oxymyoglobin was combined with Pseudomonas fluorescens or sterile nutrient broth (control) in an airtight vessel. P. fluorescens samples showed greater metmyoglobin formation and oxygen consumption than controls. The P. fluorescens population in the reaction vessels was correlated with metmyoglobin formation (r = 0.85, P < 0.05) and oxygen consumption (r = 0.91, P < 0.05). When P. fluorescens and oxymyoglobin were combined in an airtight vessel, reducing the headspace from 13 ml and 9 ml to 3 ml resulted in greater metmyoglobin formation (P < 0.05). In the meat study, beef cores prepared from longissimus lumborum were inoculated with P. fluorescens (10(7) CFU/cm2) or sterile peptone water (control), packaged under 1% O2 (+99% N2), air, or 100% O2 and stored at 4 degrees C. Inoculated beef cores showed higher bacterial loads and metmyoglobin formation than their respective controls during 10 h storage in 1% O2, 3 days in air, and 7 days in 100% O2 (P < 0.05). This finding indicated that P. fluorescens could accelerate beef discoloration. Overall, studies demonstrated that oxygen consumption concomitant with P. fluorescens growth decreased partial oxygen pressure, which accelerated oxymyoglobin oxidation.
Topics: Animals; Cattle; Culture Media; Meat; Metmyoglobin; Myoglobin; Oxidation-Reduction; Oxygen Consumption; Pseudomonas fluorescens
PubMed: 9798152
DOI: 10.4315/0362-028x-61.10.1341